JP2006324537A - Display device - Google Patents

Abstract

【Task】
Provided is a display device with less image sticking, which is to provide a display device that suppresses an increase in drive voltage associated with the elapsed light emission time of an organic light emitting element and has less image sticking.
[Solution]
On the substrate, an anode layer as a lower electrode, a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode layer as an upper electrode are arranged in this order, and a display signal voltage is applied to these organic light-emitting elements. A display device including a plurality of pixels each including a signal line for inputting, wherein the hole transport layer is composed of a hole transport material and a metal oxide material or phthalocyanines.
[Selection] Figure 1

Description

  The present invention relates to a display device having an organic light emitting element.

  In recent years, display devices using organic light-emitting elements have attracted attention as next-generation flat display devices. A display device using the organic light emitting element has excellent characteristics such as white light, a wide viewing angle, and high-speed response.

  In this type of display device, an organic light emitting element is configured in the pixel portion, and the organic light emitting element is formed on an anode layer such as ITO, a hole transport layer, a light emitting layer, an electron transport layer, and the like on a glass substrate. This is a structure formed by an organic layer and a cathode layer such as Al.

  When a voltage of about several volts is applied between the above two electrode layers, holes are injected into the anode layer, electrons are injected into the cathode layer, and the holes and electrons emit light via the hole transport layer or the electron transport layer, respectively. Bonding in layers produces excitons. When the exciton returns to the ground state, the light emitting layer emits light. The emitted light is extracted through the transparent anode layer. A structure in which emitted light passes through the substrate and is extracted from the back surface of the substrate is referred to as bottom emission, and a structure in which the emitted light is extracted from the surface of the substrate without passing through the substrate is referred to as top emission.

  There are two types of display devices using organic light emitting elements for pixels: simple matrix type organic light emitting display devices and active matrix type organic light emitting display devices that use one or more thin film transistors in a pixel. There are a voltage driving method and a current driving method for driving each display device and displaying an arbitrary image.

  In the simple matrix organic light emitting display device, organic layers such as a hole transport layer, a light emitting layer, and an electron transport layer are formed at a position where a plurality of anode lines and cathode lines intersect, and each pixel is in one frame period. Lights only for the selected time.

  In an active matrix organic light emitting display device, a driving element including 1 to 4 or more thin film transistor switching elements and capacitors is connected to an organic EL (light emitting) element constituting each pixel. All lighting during the frame period is possible.

  In the current driving method, the luminance of a light emitting element is controlled by converting image signal information into a current value and transmitting the current signal to the light emitting element. At this time, the organic light emitting element emits light emission luminance according to the input current value.

  In the voltage driving method, the luminance of a light emitting element is controlled by converting image signal information into a voltage value and transmitting the voltage signal to the light emitting element. At this time, the organic light emitting element emits light emission luminance according to the input voltage value.

  An organic light emitting device has two types of deterioration: a decrease in current efficiency and an increase in driving voltage with the elapsed light emission time. This phenomenon is observed even when the organic material is replaced, and is considered to be caused by the organic light emitting device structure itself.

  In the organic light emitting device, for the purpose of lowering the driving voltage and improving the luminous efficiency, the following Patent Document 1 using a metal oxide thin material having a work function larger than that of indium tin oxide (ITO) of 5 nm to 30 nm is disclosed. However, there is no description about the increase of the drive voltage with the light emission elapsed time.

JP-A-9-63771

  An organic light emitting device has two types of deterioration: a decrease in current efficiency and an increase in driving voltage with the elapsed light emission time.

  In an organic light emitting device driven by a current driving method, a decrease in current efficiency of the organic light emitting device causes a decrease in luminance, but an increase in driving voltage of the organic light emitting device does not cause a decrease in luminance.

  In an organic light emitting device driven by a voltage driving method, both a decrease in current efficiency and an increase in driving voltage cause a decrease in luminance.

  Accordingly, a display device including an organic light emitting element driven by a voltage driving method is more likely to cause a reduction in luminance than a current driving type display device, and as a result, has a problem that image sticking is likely to occur.

  The display device driven by the voltage driving method here is a display device having a signal line for converting image signal information into a voltage value and transmitting the voltage signal to the light emitting element. The organic light emitting element emits light emission luminance according to the input voltage value.

  Since the organic light emitting element has a deterioration in that the driving voltage increases with the elapsed light emission time, there is a problem that image sticking is likely to occur in a display device including the organic light emitting element driven by the voltage driving method.

  An object of the present invention is to provide a display device that suppresses an increase in driving voltage associated with an elapsed light emission time of an organic light emitting element and that has less image sticking in a display device that is driven by a voltage driving method using the organic light emitting element. .

  In order to solve the above problems, the present invention provides a substrate, an organic light emitting layer having a hole transport layer, a light emitting layer, and an electron transport layer, a lower electrode disposed between the organic light emitting layer and the substrate, and a lower electrode. And an upper electrode disposed on the opposite side of the substrate, and the hole transport layer is composed of a hole transport material and a metal oxide material.

  As the hole transport material, a metal oxide material having a work function of 5.5 eV or more is used.

  The hole transport layer has a mixed layer composed of a hole transport material and a metal oxide material, or a two-layer structure composed of a layer composed of a hole transport material and a layer composed of a metal oxide material. And

  Also, a substrate, an organic light emitting layer having a hole transport layer, a light emitting layer, and an electron transport layer, a lower electrode disposed between the organic light emitting layer and the substrate, and disposed on the opposite side of the substrate with respect to the lower electrode. The hole transport layer is composed of a hole transport material and a phthalocyanine material.

  The hole transport layer is a mixed layer composed of a hole transport material and a phthalocyanine material, or a two-layer structure composed of a layer composed of a hole transport material and a layer composed of a phthalocyanine material. The configuration is as follows.

  A liquid crystal display element having a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and a pair of polarizing plates; and an illumination unit for irradiating the liquid crystal display element with light. The illumination unit includes a substrate, an organic light emitting layer having a hole transport layer, a light emitting layer, and an electron transport layer, a lower electrode disposed between the organic light emitting layer and the substrate, and the opposite side of the substrate from the lower electrode. The hole transport layer has a structure composed of a hole transport material and a metal oxide material.

  A liquid crystal display element having a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and a pair of polarizing plates; and an illumination unit for irradiating the liquid crystal display element with light. The illumination unit includes a substrate, an organic light emitting layer having a hole transport layer, a light emitting layer, and an electron transport layer, a lower electrode disposed between the organic light emitting layer and the substrate, and the opposite side of the substrate from the lower electrode. And the hole transport layer is composed of a hole transport material and a phthalocyanine material.

  The present invention can provide a display device with less image sticking in a display device driven by a voltage driving method using an organic light emitting element by suppressing an increase in driving voltage with the elapsed light emission time of the organic light emitting element.

  Embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, the structure of the organic light emitting element 12 in a display device driven by a voltage driving method will be described with reference to FIGS.

  The organic light-emitting element 12 described in this embodiment is an organic light-emitting element having a structure in which emitted light is extracted from the substrate 1 side.

  FIG. 1 is a cross-sectional view showing the organic light emitting device of this example. In FIG. 1, an organic light emitting device 12 has an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, which is an upper electrode, arranged in this order on a substrate 1. As shown in FIG. 2, the hole transport layer 3 is composed of a mixed layer 7 of a hole transport material 8 and a metal oxide material 9.

  Here, when the hole transport layer 3, the light emitting layer 4, and the electron transport layer 5 are organic light emitting layers, the lower electrode is disposed between the substrate 1 and the organic light emitting layer, and the upper electrode is a substrate with respect to the lower electrode. It is arrange | positioned on the opposite side to the position where 1 is arrange | positioned.

  The substrate 1 is made of, for example, a transparent material such as quartz, glass plate, polyester, polymethyl methacrylate, polycarbonate, polysulfone, or other plastic film or sheet.

The anode layer 2 of the organic light emitting device 12 formed on the substrate 1 is preferably a conductive film having a large work function that increases the hole injection efficiency. In this embodiment, for example, indium tin oxide (ITO), SnO ₂ , which is a transparent conductive material, or gold (Au) with a film thickness of about 50 nm is formed on one surface of the substrate 1 by sputtering, vacuum deposition or the like. .

  A mixed layer 7 shown in FIG. 2 is formed on the anode layer 2 as the hole transport layer 3. The mixed layer 7 is formed by mixing the hole transport material 8 and the metal oxide material 9.

  The mixed layer 7 forms a co-deposited film of a hole transport material 8 and a metal oxide material 9 having a film thickness of 50 nm by a binary simultaneous vacuum deposition method.

The hole transport material 8 refers to a material that transports holes. In this embodiment, 4,4-bis [N-
A (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as α-NPD film) was used. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the vapor deposition rate to 0.15 ± 0.05 nm / sec.

As a material for transporting holes, specifically, N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′diamine (TPD) , 4,
4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD), 4,4 ′, 4 ″ -tri (N-carbazolyl) triphenylamine (TCTA), 1,3, 5-tris [N- (4-diphenylaminophenyl) phenylamino] benzene (p-
DPA-TDAB) is preferred. Of course, the material is not limited to these materials, and two or more of these materials may be used in combination.

The metal oxide material 9 refers to a material that forms a stable interface with the anode layer and, as a result, can suppress an increase in drive voltage with the light emission elapsed time of the organic light emitting device. In this embodiment, V ₂ O ₅ ( Vanadium pentoxide) was used. The work function of V ₂ O ₅ is 5.5 eV. At this time, about 40 mg of V ₂ O ₅ is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec.

  Besides, for example, molybdenum oxide, ruthenium oxide, aluminum oxide, bismuth oxide, gallium oxide, germanium oxide, magnesium oxide, antimony oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, zirconium oxide, iridium oxide, rhenium oxide, oxidation An oxide having a work function of 5.5 eV or more such as vanadium is used.

  The pattern of the mixed layer 7 was formed using a shadow mask. In forming the mixed layer 7, the vapor deposition rate of the hole transport material 8 and the metal oxide material 9 was 1: 1, but the present invention is not limited to this. Further, the deposition rate of the hole transport material 8 and the metal oxide material 9 is not limited to a constant value. For example, the metal deposition on the anode layer 2 side can be performed by changing the deposition rate in the course of forming the film thickness of the arbitrary mixed layer 7. The concentration of the material 9 is high and the concentration of the metal oxide material 9 on the light emitting layer 4 side may be low. Conversely, the concentration of the metal oxide material 9 on the anode layer 2 side may be low and the concentration of the metal oxide material 9 on the light emitting layer 4 side may be high. Further, the concentration distribution of the metal oxide material 9 or the concentration distribution of the hole transport material 8 in the mixed layer 7 is not constant and may be arbitrarily changed. The film thickness of the mixed layer 7 is not limited to 50 nm shown in this embodiment.

  Here, the light emitting layer 4 includes red, green and blue light emitting materials. In this embodiment, any light emitting material may be used. A triplet material may be used.

  When a light emitting material emitting blue light was used as the light emitting layer 4, a 40 nm thick distyrylarylene derivative film (hereinafter abbreviated as DPVBi) was formed by vacuum deposition. About 40 mg of each DPVBi raw material was put into a Mo sublimation boat, and the vapor deposition rate was controlled to 0.40 ± 0.05 nm / sec. The pattern at this time is formed using a shadow mask.

When a light emitting material that emits green light is used as the light emitting layer 4, a co-deposited film of tris (8-quinolinol) aluminum and quinacridone having a film thickness of 20 nm (hereinafter referred to as Alq and Qc, respectively) by a binary simultaneous vacuum deposition method. .). Alq on two Mo sublimation boards
About 40 mg and about 10 mg of Qc raw materials are added, respectively, and the deposition rate is 0.40 ±.
Vapor deposition was controlled at 0.05 nm / sec and 0.01 ± 0.005 nm / sec. The pattern at this time is formed using a shadow mask. The Alq + Qc co-evaporated film functions as a green light emitting layer.

  When a light emitting material that emits red light is used as the light emitting layer 4, a 40 nm-thick Alq and Nile Red co-deposited film (hereinafter abbreviated as Nr) was formed by a binary simultaneous vacuum deposition method. About 10 mg and about 5 mg of Alq and Nr raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. Vapor deposited. The pattern at this time is formed using a shadow mask.

  When a triplet (phosphorescent) material that emits green light is used as the light-emitting layer 4, a 40 nm-thick CBP and iridium complex (Ir (ppy) 3) co-deposited film is formed by a binary simultaneous vacuum deposition method. . Two Mo sublimation boards were charged with about 40 mg and about 10 mg of CBP and Ir (ppy) 3 raw materials, respectively, and the deposition rates were 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm, respectively. Vapor deposition was controlled at / sec. The pattern at this time was formed using a shadow mask. The CBP + Ir (ppy) 3 co-deposited film functions as a green light emitting layer.

  When a triplet (phosphorescent) material that emits red light is used as the light emitting layer 4, a CBP and PtOEP co-deposited film having a film thickness of 40 nm is formed by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of CBP and PtOEP materials are put on two Mo sublimation boards, respectively, and the deposition rate is controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And evaporated. The pattern at this time was formed using a shadow mask. The CBP + PtOEP co-deposited film functions as a red light emitting layer.

The electron transport layer 5 forms an Alq film having a thickness of 20 nm by a vacuum deposition method. At this time,
About 40 mg of the raw material was put on a Mo sublimation board, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The cathode layer 6 was formed by placing about 10 mg and about 5 mg of Al and LiF raw materials in a Mo sublimation boat, respectively, and first depositing LiF with a film thickness of 0.5 nm to 0.01 ± 0.005 nm / sec. . Thereafter, Al having a thickness of 100 nm was vapor-deposited while being controlled at 10.0 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  According to the present embodiment, the mixed layer 7 containing the metal oxide material 9 used as the hole transport layer 3 forms a stable interface with the anode layer 2, so that the drive voltage increase with the elapsed light emission time is almost 0V. An organic light emitting device 12 can be manufactured. Therefore, in a display device having a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 and driven by a voltage drive method, The hole transport layer 3 is a mixed layer 7 composed of a hole transport material 8 and a metal oxide material 9, and the display device of this embodiment can reduce seizure.

  In this embodiment, the display device having a structure in which emitted light is extracted from the substrate 1 side has been described. However, the present invention can also be applied to a display device having a plurality of organic light emitting elements 21 having the structure shown in FIG. In the organic light emitting device 21, the layers shown in this embodiment are formed on the substrate 1 in the order of the cathode layer 6, the electron transport layer 5, the light emitting layer 4, the hole transport layer 3, and the anode layer 2.

  Also in the case of the organic light emitting device 21 shown in FIG. 12, the mixed layer 7 forms a stable interface with the anode layer 2.

  Therefore, in a display device that includes a plurality of organic light emitting elements 21 having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and that is driven by a voltage drive system, The hole transport layer 3 is a mixed layer 7 composed of a hole transport material 8 and a metal oxide material 9, and the display device of this embodiment can reduce seizure.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  In the present embodiment, the display device that emits white light by combining the light emission colors of the light emitting layer 4 is also suitable as an illumination device, and particularly suitable for a backlight illumination device in a liquid crystal display device.

  Embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, the structure of the organic light emitting element 12 in a display device driven by a voltage driving method will be described with reference to FIGS. The organic light-emitting element 12 described in this embodiment is an organic light-emitting element having a structure in which emitted light is extracted from the substrate 1 side.

  FIG. 1 is a cross-sectional view showing the organic light emitting device of this example. In FIG. 1, the organic light emitting device 12 includes an anode layer 2 as a lower electrode, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 as an upper electrode on a substrate 1. As shown in FIG. 3, the hole transport layer 3 is a two-layered hole transport layer 13 composed of a hole transport material 8 and a metal oxide material 9.

  The substrate 1 is made of, for example, a transparent material such as quartz, glass plate, polyester, polymethyl methacrylate, polycarbonate, polysulfone, or other plastic film or sheet.

In this embodiment, the anode layer 2 of the organic light emitting element 12 formed on the substrate 1 is made of, for example, indium tin oxide (ITO), SnO ₂ , which is a transparent conductive material, or gold (Au) having a film thickness of about 50 nm. It is formed on one surface of the substrate 1 by sputtering, vacuum deposition or the like.

  On the anode layer 2, a hole transport layer 13 having a two-layer structure made of the hole transport material 8 and the metal oxide material 9 shown in FIG. 3 is formed as the hole transport layer 3.

  The hole transport layer 13 forms a two-layer structure film of a hole transport material 8 and a metal oxide material 9 having a film thickness of 50 nm by a vacuum deposition method.

As the metal oxide material 9, a layer of the metal oxide material 9 having a film thickness of 3 nm was formed by vacuum deposition using V ₂ O ₅ (vanadium pentoxide). The work function of V ₂ O ₅ is 5.5 eV. At this time, about 40 mg of V ₂ O ₅ is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec.

  The hole transporting material 8 is a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film) having a film thickness of 47 nm by vacuum deposition. A layer of hole transport material 8 was formed. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the vapor deposition rate to 0.15 ± 0.05 nm / sec.

  The pattern of the hole transport layer 13 was formed using a shadow mask. The film thickness of the hole transport layer 13 is not limited to 50 nm shown in this embodiment. The film thickness of the metal oxide material 9 is not limited to 3 nm. The film thickness of the hole transport material 8 is not limited to 47 nm. The film thickness ratio between the hole transport material 8 and the metal oxide material 9 of the hole transport layer 13 may be an arbitrary film thickness ratio.

  Two types of the hole transport material 8 and the metal oxide material 9 forming the hole transport layer 13 may be vapor-deposited at the same time, or the hole transport layer may be formed by adjusting the respective vapor deposition rates. In the case of the present embodiment, the deposition rate of the hole transport material 8 is controlled to a deposition rate close to, for example, approximately 0 nm / sec, and the deposition rate of the metal oxide material 9 only needs to be larger than the deposition rate of the hole transport material 8. Vapor deposition may be performed at 1.0 ± 0.05 nm / sec. Thereafter, the vapor deposition rate of the hole transport material 8 is vapor-deposited at, for example, 1.0 ± 0.05 nm / sec, and the vapor deposition rate of the metal oxide material 9 is controlled to be smaller than the vapor deposition rate of the hole transport material 8, for example, vapor deposition at approximately 0 nm / sec. To do. By doing so, the vapor deposition rate of about 0 nm / sec, which is too small, cannot reach the anode layer 2 formed on the substrate 1, so that the hole transport layer 13 shown in FIG. 3 can be formed. . Since the organic light emitting device manufactured by such a method reduces the time for forming the organic film, the production cost can be reduced as a result, and an inexpensive display device can be provided.

  Here, the light emitting layer 4 includes red, green, and blue light emitting materials. In this embodiment, any light emitting material may be used. A triplet material may be used.

  When a light emitting material emitting blue light was used as the light emitting layer 4, a 40 nm thick distyrylarylene derivative film (hereinafter abbreviated as DPVBi) was formed by vacuum deposition. About 40 mg of each DPVBi raw material was put into a Mo sublimation boat, and the vapor deposition rate was controlled to 0.40 ± 0.05 nm / sec. The pattern at this time is formed using a shadow mask.

When a light emitting material that emits green light is used as the light emitting layer 4, a co-deposited film of tris (8-quinolinol) aluminum and quinacridone having a film thickness of 20 nm (hereinafter referred to as Alq and Qc, respectively) by a binary simultaneous vacuum deposition method. .). Alq on two Mo sublimation boards
About 40 mg and about 10 mg of Qc raw materials were added, respectively, and the vapor deposition rates were controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. The pattern at this time is formed using a shadow mask. The Alq + Qc co-evaporated film functions as a green light emitting layer.

  When a light emitting material that emits red light is used as the light emitting layer 4, a 40 nm-thick Alq and Nile Red co-deposited film (hereinafter abbreviated as Nr) was formed by a binary simultaneous vacuum deposition method. About 10 mg and about 5 mg of Alq and Nr raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. Vapor deposited. The pattern at this time is formed using a shadow mask.

  When a triplet (phosphorescent) material that emits green light is used as the light-emitting layer 4, a 40 nm-thick CBP and iridium complex (Ir (ppy) 3) co-deposited film is formed by a binary simultaneous vacuum deposition method. . Two Mo sublimation boards were charged with about 40 mg and about 10 mg of CBP and Ir (ppy) 3 raw materials, respectively, and the deposition rates were 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm, respectively. Vapor deposition was controlled at / sec. The pattern at this time was formed using a shadow mask. The CBP + Ir (ppy) 3 co-deposited film functions as a green light emitting layer.

  When a triplet (phosphorescent) material that emits red light is used as the light emitting layer 4, a CBP and PtOEP co-deposited film having a film thickness of 40 nm is formed by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of CBP and PtOEP materials are put on two Mo sublimation boards, respectively, and the deposition rate is controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And evaporated. The pattern at this time was formed using a shadow mask. The CBP + PtOEP co-deposited film functions as a red light emitting layer.

The electron transport layer 5 forms an Alq film having a thickness of 20 nm by a vacuum deposition method. At this time,
About 40 mg of the raw material was put on a Mo sublimation board, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The cathode layer 6 was formed by placing about 10 mg and about 5 mg of Al and LiF raw materials in a Mo sublimation boat, respectively, and first depositing LiF with a film thickness of 0.5 nm to 0.01 ± 0.005 nm / sec. . Thereafter, Al having a thickness of 100 nm was vapor-deposited while being controlled at 10.0 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  According to the present embodiment, the hole transport layer 13 having the two-layer structure including the metal oxide material 9 used as the hole transport layer 3 forms a stable interface with the anode layer 2, so that the drive voltage associated with the elapsed light emission time is increased. An organic light emitting device 12 having a rise of approximately 0 V can be manufactured. Therefore, in a display device having a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 and driven by a voltage drive method, The hole transport layer 3 is a hole transport layer 13 having a two-layer structure composed of a hole transport material 8 and a metal oxide material 9, and the display device of this embodiment can reduce seizure.

  In this embodiment, the display device having a structure in which emitted light is extracted from the substrate 1 side has been described. However, the present invention can also be applied to a display device having a plurality of organic light emitting elements 21 having the structure shown in FIG. The organic light-emitting element 21 includes a cathode layer 6 serving as a lower electrode, an electron transport layer 5, a light-emitting layer 4, a hole transport layer 3, and an anode layer serving as an upper electrode on the substrate 1 in the present embodiment. Form in order of 2.

  Also in the case of the organic light emitting device 21 shown in FIG. 12, the hole transport layer 13 forms a stable interface with the anode layer 2, and therefore it is possible to suppress an increase in driving voltage with the elapsed light emission time. Therefore, in a display device that includes a plurality of organic light emitting elements 21 having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and that is driven by a voltage drive system, The hole transport layer 3 is a hole transport layer 13 made of a hole transport material 8 and a metal oxide material 9, and the display device of this embodiment can reduce seizure.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  In this embodiment, a display device that emits white light by combining the light emission colors of the light emitting layer 4 is also suitable as a lighting device, and in particular, a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, In a liquid crystal display element having a pair of polarizing plates arranged on the outside of a pair of substrates, the above-described organic light-emitting element, that is, the substrate 1, the hole transport layer 3, the light-emitting layer 4, and the electrons are used as the backlight. It is suitable to use an organic light emitting device comprising an organic light emitting layer having a transport layer 5 and an upper electrode and a lower electrode sandwiching the organic light emitting layer.

  Embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, the structure of the organic light emitting element 12 in a display device driven by a voltage driving method will be described with reference to FIGS. The organic light-emitting element 12 described in this embodiment is an organic light-emitting element having a structure in which emitted light is extracted from the substrate 1 side.

  FIG. 1 is a cross-sectional view showing the organic light emitting device of this example. In FIG. 1, an organic light emitting device 12 includes an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 on a substrate 1, and the hole transport layer 3 is shown in FIG. As shown in FIG. 4, the hole transporting layer 14 is a two-layered hole transporting layer 14 composed of a hole transporting material 8 and a mixed layer 7. Further, the organic light emitting device 12 shown in this embodiment is characterized in that the hole transport material 8 of the hole transport layer 14 is disposed on the light emitting layer 4 side.

  The substrate 1 is made of, for example, a transparent material such as quartz, glass plate, polyester, polymethyl methacrylate, polycarbonate, polysulfone, or other plastic film or sheet.

In this embodiment, the anode layer 2 of the organic light emitting element 12 formed on the substrate 1 is, for example, indium tin oxide (ITO), SnO ₂ , which is a transparent conductive material, or a film thickness of 50.
About 1 nm of gold (Au) is formed on one surface of the substrate 1 by sputtering, vacuum deposition or the like.

  On the anode layer 2, a hole transport layer 14 having a two-layer structure including the hole transport material 8 and the mixed layer 7 shown in FIG. 4 is formed as the hole transport layer 3.

  The hole transport layer 14 forms a two-layer structure film composed of the hole transport material 8 having a film thickness of 50 nm and the mixed layer 7 by a vacuum deposition method.

  The mixed layer 7 formed on the anode layer 2 is formed by a co-deposition film of a 10 nm-thick hole transport material 8 and a metal oxide material 9 by a binary simultaneous vacuum deposition method.

  As the hole transport material 8, a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film) was used. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the deposition rate to 0.15 ± 0.05 nm / sec.

As the metal oxide material 9, V ₂ O ₅ (vanadium pentoxide) was used. The work function of V ₂ O ₅ is 5.5
eV. At this time, about 40 mg of V ₂ O ₅ is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec.

  The pattern at this time was formed using a shadow mask. In forming the mixed layer 7, the vapor deposition rate of the hole transport material 8 and the metal oxide material 9 was 1: 1, but the present invention is not limited to this. Further, the deposition rate of the hole transport material 8 and the metal oxide material 9 is not limited to a constant value. For example, the metal deposition on the anode layer 2 side can be performed by changing the deposition rate in the course of forming the film thickness of the arbitrary mixed layer 7. The concentration of the material 9 is high and the concentration of the metal oxide material 9 on the light emitting layer 4 side may be low. Conversely, the concentration of the metal oxide material 9 on the anode layer side may be low and the concentration of the metal oxide material 9 on the light emitting layer 4 side may be high. Further, the concentration distribution of the metal oxide material 9 or the concentration distribution of the hole transport material 8 in the mixed layer 7 is not constant and may be arbitrarily changed. The film thickness of the mixed layer 7 is not limited to 10 nm shown in this embodiment.

The hole transport material 8 formed on the mixed layer 7 is a vacuum using a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film). A 40 nm thick hole transport material 8 layer was formed by vapor deposition. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the deposition rate to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The film thickness of the hole transport layer 14 is not limited to 50 nm shown in this embodiment. The film thickness of the mixed layer 7 is not limited to 10 nm, and the film thickness of the hole transport material 8 is not limited to 40 nm. The film thickness ratio between the hole transport material 8 and the mixed layer 7 of the hole transport layer 14 may be an arbitrary film thickness ratio. The hole transport material 8 of the hole transport layer 14 is in contact with the light emitting layer 4 to be formed next.

  Here, the light emitting layer 4 includes red, green, and blue light emitting materials. In this embodiment, any light emitting material may be used. A triplet material may be used.

  When a light emitting material emitting blue light was used as the light emitting layer 4, a 40 nm thick distyrylarylene derivative film (hereinafter abbreviated as DPVBi) was formed by vacuum deposition. About 40 mg of each DPVBi raw material was put into a Mo sublimation boat, and the vapor deposition rate was controlled to 0.40 ± 0.05 nm / sec. The pattern at this time is formed using a shadow mask.

When a light emitting material that emits green light is used as the light emitting layer 4, a co-deposited film of tris (8-quinolinol) aluminum and quinacridone having a film thickness of 20 nm (hereinafter referred to as Alq and Qc, respectively) by a binary simultaneous vacuum deposition method. .). Alq on two Mo sublimation boards
About 40 mg and about 10 mg of Qc raw materials were added, respectively, and the vapor deposition rates were controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. The pattern at this time is formed using a shadow mask. The Alq + Qc co-evaporated film functions as a green light emitting layer.

  When a light emitting material that emits red light is used as the light emitting layer 4, a 40 nm-thick Alq and Nile Red co-deposited film (hereinafter abbreviated as Nr) was formed by a binary simultaneous vacuum deposition method. About 10 mg and about 5 mg of Alq and Nr raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. Vapor deposited. The pattern at this time is formed using a shadow mask.

  When a triplet (phosphorescent) material that emits green light is used as the light-emitting layer 4, a 40 nm-thick CBP and iridium complex (Ir (ppy) 3) co-deposited film is formed by a binary simultaneous vacuum deposition method. . Two Mo sublimation boards were charged with about 40 mg and about 10 mg of CBP and Ir (ppy) 3 raw materials, respectively, and the deposition rates were 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm, respectively. Vapor deposition was controlled at / sec. The pattern at this time was formed using a shadow mask. The CBP + Ir (ppy) 3 co-deposited film functions as a green light emitting layer.

  When a triplet (phosphorescent) material that emits red light is used as the light emitting layer 4, a CBP and PtOEP co-deposited film having a film thickness of 40 nm is formed by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of CBP and PtOEP materials are put on two Mo sublimation boards, respectively, and the deposition rate is controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And evaporated. The pattern at this time was formed using a shadow mask. The CBP + PtOEP co-deposited film functions as a red light emitting layer.

The electron transport layer 5 forms an Alq film having a thickness of 20 nm by a vacuum deposition method. At this time,
About 40 mg of the raw material was put on a Mo sublimation board, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The cathode layer 6 was formed by placing about 10 mg and about 5 mg of Al and LiF raw materials in a Mo sublimation boat, respectively, and first depositing LiF with a film thickness of 0.5 nm to 0.01 ± 0.005 nm / sec. . Thereafter, Al having a thickness of 100 nm was vapor-deposited while being controlled at 10.0 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  According to the present embodiment, since the hole transport layer 14 having a two-layer structure formed from the mixed layer 7 containing the metal oxide material 9 forms a stable interface with the anode layer 2, the driving voltage associated with the elapsed time of light emission. An organic light emitting device 12 having a rise of approximately 0 V can be manufactured. Therefore, in a display device having a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 and driven by a voltage drive method, The hole transport layer 3 is a hole transport layer 14 having a two-layer structure composed of a hole transport material 8 and a mixed layer 7. The display device of this embodiment can reduce seizure.

  In this embodiment, the display device having a structure in which emitted light is extracted from the substrate 1 side has been described. However, the present invention can also be applied to a display device having a plurality of organic light emitting elements 21 having the structure shown in FIG. In the organic light emitting device 21, the layers shown in this embodiment are formed on the substrate 1 in the order of the cathode layer 6, the electron transport layer 5, the light emitting layer 4, the hole transport layer 3, and the anode layer 2.

  Also in the case of the organic light emitting device 21 shown in FIG. 12, the hole transport layer 14 forms a stable interface with the anode layer 2, and therefore it is possible to suppress an increase in driving voltage with the elapsed light emission time. Therefore, in a display device that includes a plurality of organic light emitting elements 21 having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and that is driven by a voltage drive system, The hole transport layer 3 is a hole transport layer 14 having a two-layer structure composed of a hole transport material 8 and a mixed layer 7. The display device of this embodiment can reduce seizure.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  In the present embodiment, a display device that emits white light by combining the light emission colors of the light emitting layer 4 is suitable as an illumination device as in the other embodiments, and particularly suitable for a backlight illumination device in a liquid crystal display device. .

  Embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, the structure of the organic light emitting element 12 in a display device driven by a voltage driving method will be described with reference to FIGS. The organic light-emitting element 12 described in this embodiment is an organic light-emitting element having a structure in which emitted light is extracted from the substrate 1 side.

  FIG. 1 is a cross-sectional view showing the organic light emitting device of this example. In FIG. 1, an organic light emitting device 12 includes an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 on a substrate 1, and the hole transport layer 3 is shown in FIG. As shown in FIG. 5, the hole transport layer 15 is a three-layered hole transport layer 15 composed of the hole transport material 8, the mixed layer 7, and the metal oxide material 9. The organic light emitting device 12 shown in this example is characterized in that the hole transport material 8 of the hole transport layer 15 is disposed on the light emitting layer 4 side.

  The substrate 1 is made of, for example, a transparent material such as quartz, glass plate, polyester, polymethyl methacrylate, polycarbonate, polysulfone, or other plastic film or sheet.

In this embodiment, the anode layer 2 of the organic light emitting element 12 formed on the substrate 1 is, for example, indium tin oxide (ITO), SnO ₂ , which is a transparent conductive material, or a film thickness of 50.
About 1 nm of gold (Au) is formed on one surface of the substrate 1 by sputtering, vacuum deposition or the like.

  On the anode layer 2, a hole transport layer 14 having a three-layer structure including the hole transport material 8, the mixed layer 7, and the metal oxide material 9 shown in FIG. 5 is formed as the hole transport layer 3.

  The hole transport layer 15 forms a three-layer structure film made of a hole transport material 8 having a film thickness of 50 nm, a mixed layer 7 and a metal oxide material 9 by a vacuum deposition method.

V ₂ O ₅ (vanadium pentoxide) was used as the metal oxide material 9 formed on the anode layer 2.
The work function of V ₂ O ₅ is 5.5 eV. At this time, about 40 mg of V ₂ O ₅ is put on a Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec. The film thickness of the metal oxide material 9 shown in this embodiment is 3 nm.

  The mixed layer 7 is formed by a co-deposition film of a 7 nm-thick hole transport material 8 and a metal oxide material 9 by a binary simultaneous vacuum deposition method.

  As the hole transport material 8, a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film) was used. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the vapor deposition rate to 0.15 ± 0.05 nm / sec.

As the metal oxide material 9, V ₂ O ₅ (vanadium pentoxide) was used. The work function of V ₂ O ₅ is 5.5
eV. At this time, about 40 mg of V ₂ O ₅ is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec.

  The pattern at this time was formed using a shadow mask. In forming the mixed layer 7, the vapor deposition rate of the hole transport material 8 and the metal oxide material 9 was 1: 1, but the present invention is not limited to this. Further, the deposition rate of the hole transport material 8 and the metal oxide material 9 is not limited to a constant value. For example, the metal deposition on the anode layer 2 side can be performed by changing the deposition rate in the course of forming the film thickness of the arbitrary mixed layer 7. The concentration of the material 9 is high and the concentration of the metal oxide material 9 on the light emitting layer 4 side may be low. Conversely, the concentration of the metal oxide material 9 on the anode layer 2 side may be low and the concentration of the metal oxide material 9 on the light emitting layer 4 side may be high. Further, the concentration distribution of the metal oxide material 9 or the concentration distribution of the hole transport material 8 in the mixed layer 7 is not constant and may be arbitrarily changed. The film thickness of the mixed layer 7 is not limited to 7 nm shown in this embodiment.

The hole transport material 8 formed on the mixed layer 7 is a vacuum using a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film). A 40 nm thick hole transport material 8 layer was formed by vapor deposition. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the deposition rate to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The film thickness of the hole transport layer 14 is not limited to 50 nm shown in this embodiment. The thickness of the mixed layer 7 is not limited to 7 nm, the thickness of the hole transport material 8 is 40 nm, and the thickness of the metal oxide material 9 is not limited to 3 nm. The film thickness ratio of the hole transport material 8, the mixed layer 7, and the metal oxide material 9 of the hole transport layer 14 may be an arbitrary film thickness ratio. The hole transport material 8 of the hole transport layer 15 is in contact with the light emitting layer 4 to be formed next.

  Here, the light emitting layer 4 includes red, green, and blue light emitting materials. In this embodiment, any light emitting material may be used. A triplet material may be used.

  When a light emitting material emitting blue light was used as the light emitting layer 4, a 40 nm thick distyrylarylene derivative film (hereinafter abbreviated as DPVBi) was formed by vacuum deposition. About 40 mg of each DPVBi raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled at 0.40 ± 0.05 nm / sec. The pattern at this time is formed using a shadow mask.

When a light emitting material that emits green light is used as the light emitting layer 4, a co-deposited film of tris (8-quinolinol) aluminum and quinacridone having a film thickness of 20 nm (hereinafter referred to as Alq and Qc, respectively) by a binary simultaneous vacuum deposition method. .). Alq on two Mo sublimation boards
About 40 mg and about 10 mg of Qc raw materials were added, respectively, and the vapor deposition rates were controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. The pattern at this time is formed using a shadow mask. The Alq + Qc co-evaporated film functions as a green light emitting layer.

  When a light emitting material that emits red light is used as the light emitting layer 4, a 40 nm-thick Alq and Nile Red co-deposited film (hereinafter abbreviated as Nr) was formed by a binary simultaneous vacuum deposition method. About 10 mg and about 5 mg of Alq and Nr raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. Vapor deposited. The pattern at this time is formed using a shadow mask.

When a triplet (phosphorescent) material that emits green light is used as the light-emitting layer 4, a 40 nm-thick CBP and iridium complex (Ir (ppy) 3) co-deposited film is formed by a binary simultaneous vacuum deposition method. . Two Mo sublimation boards were charged with about 40 mg and about 10 mg of CBP and Ir (ppy) 3 raw materials, respectively, and the deposition rates were 0.40 ± 0.05 nm / sec and 0.01 ± 0.005, respectively.
Vapor deposition was controlled at nm / sec. The pattern at this time was formed using a shadow mask. The CBP + Ir (ppy) 3 co-deposited film functions as a green light emitting layer.

  When a triplet (phosphorescent) material that emits red light is used as the light emitting layer 4, a CBP and PtOEP co-deposited film having a film thickness of 40 nm is formed by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of CBP and PtOEP materials are put on two Mo sublimation boards, respectively, and the deposition rate is controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And evaporated. The pattern at this time was formed using a shadow mask. The CBP + PtOEP co-deposited film functions as a red light emitting layer.

The electron transport layer 5 forms an Alq film having a thickness of 20 nm by a vacuum deposition method. At this time,
About 40 mg of the raw material was put on a Mo sublimation board, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The cathode layer 6 was formed by placing about 10 mg and about 5 mg of Al and LiF raw materials in a Mo sublimation boat, respectively, and first depositing LiF with a film thickness of 0.5 nm to 0.01 ± 0.005 nm / sec. . Thereafter, Al having a thickness of 100 nm was vapor-deposited while being controlled at 10.0 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  According to the organic light emitting device 12 of this example, the hole transport layer 15 used as the hole transport layer 3 forms a stable interface with the anode layer 2, so that the drive voltage increase with the elapsed light emission time is almost 0V. The organic light emitting device 12 can be manufactured. Therefore, in a display device having a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 and driven by a voltage drive method, The hole transport layer 3 is a hole transport layer 15 having a three-layer structure composed of a hole transport material 8, a mixed layer 7, and a metal oxide material 9. The display device according to this embodiment reduces seizure. be able to.

  In this embodiment, the display device having a structure in which emitted light is extracted from the substrate 1 side has been described. However, the present invention can also be applied to a display device having a plurality of organic light emitting elements 21 having the structure shown in FIG. In the organic light emitting device 21, the layers shown in this embodiment are formed on the substrate 1 in the order of the cathode layer 6, the electron transport layer 5, the light emitting layer 4, the hole transport layer 3, and the anode layer 2.

  Also in the case of the organic light emitting device 21 shown in FIG. 12, the hole transport layer 15 forms a stable interface with the anode layer 2, so that it is possible to suppress an increase in driving voltage with the light emission elapsed time. Therefore, in a display device that includes a plurality of organic light emitting elements 21 having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and that is driven by a voltage drive system, The hole transport layer 3 is a hole transport layer 15 having a three-layer structure composed of a hole transport material 8, a mixed layer 7, and a metal oxide material 9. The display device according to this embodiment reduces seizure. be able to.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  In the present embodiment, the display device that emits white light by combining the light emission colors of the light emitting layer 4 is also suitable as an illumination device, and particularly suitable for a backlight illumination device in a liquid crystal display device.

  Embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, the structure of the organic light emitting element 12 in a display device driven by a voltage driving method will be described with reference to FIGS. The organic light-emitting element 12 described in this embodiment is an organic light-emitting element having a structure in which emitted light is extracted from the substrate 1 side.

  FIG. 1 is a cross-sectional view showing the organic light emitting device of this example. In FIG. 1, an organic light emitting device 12 includes an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 on a substrate 1, and the hole transport layer 3 is shown in FIG. As shown in FIG. 6, the hole transporting layer 16 is a three-layered hole transporting layer 16 including a hole transporting material 8, a metal oxide material 9, and a mixed layer 7. Further, the organic light emitting device 12 shown in this embodiment is characterized in that the hole transport material 8 of the hole transport layer 16 is disposed on the light emitting layer 4 side.

  The substrate 1 is made of, for example, a transparent material such as quartz, glass plate, polyester, polymethyl methacrylate, polycarbonate, polysulfone, or other plastic film or sheet.

In this embodiment, the anode layer 2 of the organic light emitting element 12 formed on the substrate 1 is, for example, indium tin oxide (ITO), SnO ₂ , which is a transparent conductive material, or a film thickness of 50.
About 1 nm of gold (Au) is formed on one surface of the substrate 1 by sputtering, vacuum deposition or the like.

  On the anode layer 2, a hole transport layer 16 having a three-layer structure including the hole transport material 8, the metal oxide material 9, and the mixed layer 7 shown in FIG. 6 is formed as the hole transport layer 3.

  The hole transport layer 16 forms a three-layer structure film composed of a hole transport material 8 having a film thickness of 50 nm, a metal oxide material 9 and a mixed layer 7 by a vacuum deposition method.

  The mixed layer 7 formed on the anode layer 2 is formed of a co-deposited film of a 7 nm-thick hole transport material 8 and a metal oxide material 9 by a binary simultaneous vacuum deposition method.

  As the hole transport material 8, a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film) was used. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the deposition rate to 0.15 ± 0.05 nm / sec.

As the metal oxide material 9, V ₂ O ₅ (vanadium pentoxide) was used. The work function of V ₂ O ₅ is 5.5
eV. At this time, about 40 mg of V ₂ O ₅ is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec.

  The pattern at this time was formed using a shadow mask. In forming the mixed layer 7, the vapor deposition rate of the hole transport material 8 and the metal oxide material 9 was 1: 1, but the present invention is not limited to this. Further, the vapor deposition rates of the hole transport material 8 and the metal oxide material are not limited to a constant value. For example, the metal oxide material on the anode layer 2 side is changed by changing the vapor deposition rate in the course of forming the film thickness of the arbitrary mixed layer 7. The concentration of 9 may be high and the concentration of the metal oxide material 9 on the light emitting layer 4 side may be low. Conversely, the concentration of the metal oxide material 9 on the anode layer side may be low and the concentration of the metal oxide material 9 on the light emitting layer 4 side may be high. Further, the concentration distribution of the metal oxide material or the concentration distribution of the hole transport material in the mixed layer 7 is not constant and may be arbitrarily changed. The film thickness of the mixed layer 7 is not limited to 7 nm shown in this embodiment.

V ₂ O ₅ (vanadium pentoxide) was used as the metal oxide material 9 formed on the mixed layer 7.
The work function of V ₂ O ₅ is 5.5 eV. At this time, about 40 mg of V ₂ O ₅ is put on a Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec. The film thickness of the metal oxide material 9 shown in this embodiment is 3 nm.

  As the hole transport material 8 formed on the metal oxide material 9, a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film) is used. A layer of hole transport material 8 having a film thickness of 40 nm was formed by vacuum deposition. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the vapor deposition rate to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The film thickness of the hole transport layer 16 is not limited to 50 nm shown in this embodiment. The thickness of the mixed layer 7 is not limited to 7 nm, the thickness of the hole transport material 8 is 40 nm, and the thickness of the metal oxide material 9 is not limited to 3 nm. The film thickness ratio of the hole transport material 8, the mixed layer 7, and the metal oxide material 9 of the hole transport layer 16 may be any film thickness ratio. The hole transport material 8 of the hole transport layer 16 is in contact with the light emitting layer 4 to be formed next.

  Here, the light emitting layer 4 includes red, green, and blue light emitting materials. In this embodiment, any light emitting material may be used. A triplet material may be used.

  When a light emitting material emitting blue light was used as the light emitting layer 4, a 40 nm thick distyrylarylene derivative film (hereinafter abbreviated as DPVBi) was formed by vacuum deposition. About 40 mg of each DPVBi raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled at 0.40 ± 0.05 nm / sec. The pattern at this time is formed using a shadow mask.

When a light emitting material that emits green light is used as the light emitting layer 4, a co-deposited film of tris (8-quinolinol) aluminum and quinacridone having a film thickness of 20 nm (hereinafter referred to as Alq and Qc, respectively) by a binary simultaneous vacuum deposition method. .). Alq on two Mo sublimation boards
About 40 mg and about 10 mg of Qc raw materials were added, respectively, and the vapor deposition rates were controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. The pattern at this time is formed using a shadow mask. The Alq + Qc co-evaporated film functions as a green light emitting layer.

  When a light emitting material that emits red light is used as the light emitting layer 4, a 40 nm-thick Alq and Nile Red co-deposited film (hereinafter abbreviated as Nr) was formed by a binary simultaneous vacuum deposition method. About 10 mg and about 5 mg of Alq and Nr raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. Vapor deposited. The pattern at this time is formed using a shadow mask.

When a triplet (phosphorescent) material that emits green light is used as the light-emitting layer 4, a 40 nm-thick CBP and iridium complex (Ir (ppy) 3) co-deposited film is formed by a binary simultaneous vacuum deposition method. . Two Mo sublimation boards were charged with about 40 mg and about 10 mg of CBP and Ir (ppy) 3 raw materials, respectively, and the deposition rates were 0.40 ± 0.05 nm / sec and 0.01 ± 0.005, respectively.
Vapor deposition was controlled at nm / sec. The pattern at this time was formed using a shadow mask. The CBP + Ir (ppy) 3 co-deposited film functions as a green light emitting layer.

  When a triplet (phosphorescent) material that emits red light is used as the light emitting layer 4, a CBP and PtOEP co-deposited film having a film thickness of 40 nm is formed by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of CBP and PtOEP materials are put on two Mo sublimation boards, respectively, and the deposition rate is controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And evaporated. The pattern at this time was formed using a shadow mask. The CBP + PtOEP co-deposited film functions as a red light emitting layer.

The electron transport layer 5 forms an Alq film having a thickness of 20 nm by a vacuum deposition method. At this time,
About 40 mg of the raw material was put on a Mo sublimation board, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The cathode layer 6 was formed by placing about 10 mg and about 5 mg of Al and LiF raw materials in a Mo sublimation boat, respectively, and first depositing LiF with a film thickness of 0.5 nm to 0.01 ± 0.005 nm / sec. . Thereafter, Al having a thickness of 100 nm was vapor-deposited while being controlled at 10.0 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  According to the organic light emitting device 12 of this example, the hole transport layer 16 used as the hole transport layer 3 forms a stable interface with the anode layer 2, so that the drive voltage increase with the elapsed light emission time is almost 0V. The organic light emitting device 12 can be manufactured. Therefore, in a display device having a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 and driven by a voltage drive method, The hole transport layer 3 is a hole transport layer 16 having a three-layer structure including a hole transport material 8, a metal oxide material 9, and a mixed layer 7. be able to.

  In this embodiment, the display device having a structure in which emitted light is extracted from the substrate 1 side has been described. However, the present invention can also be applied to a display device having a plurality of organic light emitting elements 21 having the structure shown in FIG. In the organic light emitting device 21, the layers shown in this embodiment are formed on the substrate 1 in the order of the cathode layer 6, the electron transport layer 5, the light emitting layer 4, the hole transport layer 3, and the anode layer 2.

  Also in the case of the organic light emitting device 21 shown in FIG. 12, the hole transport layer 16 forms a stable interface with the anode layer 2, and thus it is possible to suppress an increase in driving voltage with the elapsed light emission time. Therefore, in a display device that includes a plurality of organic light emitting elements 21 having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and that is driven by a voltage drive system, The hole transport layer 3 is a hole transport layer 16 having a three-layer structure including a hole transport material 8, a metal oxide material 9, and a mixed layer 7. be able to.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  In the present embodiment, the display device that emits white light by combining the light emission colors of the light emitting layer 4 is also suitable as an illumination device, and particularly suitable for a backlight illumination device in a liquid crystal display device.

  Embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, the structure of the organic light emitting element 12 in a display device driven by a voltage driving method will be described with reference to FIGS. The organic light-emitting element 12 described in this embodiment is an organic light-emitting element having a structure in which emitted light is extracted from the substrate 1 side.

  FIG. 1 is a cross-sectional view showing the organic light emitting device of this example. In FIG. 1, the organic light emitting device 12 includes an anode layer 2 as a lower electrode, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 as an upper electrode on a substrate 1. The hole transport layer 3 is composed of a mixed layer 10 of a hole transport material 8 and phthalocyanines 11.

  The substrate 1 is made of, for example, a transparent material such as quartz, glass plate, polyester, polymethyl methacrylate, polycarbonate, polysulfone, or other plastic film or sheet.

In this embodiment, the anode layer 2 of the organic light emitting element 12 formed on the substrate 1 is, for example, indium tin oxide (ITO), SnO ₂ , which is a transparent conductive material, or a film thickness of 50.
About 1 nm of gold (Au) is formed on one surface of the substrate 1 by sputtering, vacuum deposition or the like.

  A mixed layer 10 shown in FIG. 6 is formed as the hole transport layer 3 on the anode layer 2. The mixed layer 10 is formed by mixing the hole transport material 8 and the phthalocyanines 11.

  The mixed layer 10 forms a co-deposited film of a 50 nm-thick hole transport material 8 and phthalocyanines 11 by a binary simultaneous vacuum deposition method.

  As the hole transport material 8, a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film) was used. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the deposition rate to 0.15 ± 0.05 nm / sec.

  Phthalocyanines 11 are materials that form a stable interface with the anode layer, and as a result can suppress an increase in driving voltage with the elapsed light emission time of the organic light emitting device, and work functions such as copper phthalocyanine are 5.2 eV or more. It is a substance. In this example, copper phthalocyanine (CuPc) was used. The work function of CuPc is 5.2 eV. At this time, about 40 mg of CuPc is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec.

  Since the phthalocyanine examples are crystalline films and not amorphous, the copper phthalocyanine film itself is stable to heat. For this reason, a stable interface with the anode layer is formed, and as a result, an increase in driving voltage accompanying the light emission elapsed time of the organic light emitting device can be suppressed.

The pattern at this time was formed using a shadow mask. In forming the mixed layer 10, the vapor transport rate of the hole transport material 8 and the phthalocyanines 11 was co-evaporated at 1: 1, but the present invention is not limited to this. Further, the deposition rate of the hole transport material 8 and the phthalocyanines 11 is not limited to a constant value. For example, the deposition rate is changed in the course of forming the film thickness of the arbitrary mixed layer 10, for example, the phthalocyanines 11 on the anode layer 2 side. The concentration of phthalocyanines 11 on the light emitting layer 4 side may be low. Conversely, the concentration of the phthalocyanines 11 on the anode layer side may be low and the concentration of the phthalocyanines 11 on the light emitting layer 4 side may be high. Further, the concentration distribution of the phthalocyanines 11 or the concentration distribution of the hole transport material 8 in the mixed layer 10 is not constant and may be arbitrarily changed. The film thickness of the mixed layer 10 is not limited to 50 nm shown in this embodiment.

  Here, the light emitting layer 4 includes red, green, and blue light emitting materials. In this embodiment, any light emitting material may be used. A triplet material may be used.

  When a light emitting material emitting blue light was used as the light emitting layer 4, a 40 nm thick distyrylarylene derivative film (hereinafter abbreviated as DPVBi) was formed by vacuum deposition. About 40 mg of each DPVBi raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled at 0.40 ± 0.05 nm / sec. The pattern at this time is formed using a shadow mask.

When a light emitting material that emits green light is used as the light emitting layer 4, a co-deposited film of tris (8-quinolinol) aluminum and quinacridone having a film thickness of 20 nm (hereinafter referred to as Alq and Qc, respectively) by a binary simultaneous vacuum deposition method. .). Alq on two Mo sublimation boards
About 40 mg and about 10 mg of Qc raw materials were added, respectively, and the vapor deposition rates were controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. The pattern at this time is formed using a shadow mask. The Alq + Qc co-evaporated film functions as a green light emitting layer.

  When a light emitting material that emits red light is used as the light emitting layer 4, a 40 nm-thick Alq and Nile Red co-deposited film (hereinafter abbreviated as Nr) was formed by a binary simultaneous vacuum deposition method. About 10 mg and about 5 mg of Alq and Nr raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. Vapor deposited. The pattern at this time is formed using a shadow mask.

  When a triplet (phosphorescent) material that emits green light is used as the light-emitting layer 4, a 40 nm-thick CBP and iridium complex (Ir (ppy) 3) co-deposited film is formed by a binary simultaneous vacuum deposition method. . Two Mo sublimation boards were charged with about 40 mg and about 10 mg of CBP and Ir (ppy) 3 raw materials, respectively, and the deposition rates were 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm, respectively. Vapor deposition was controlled at / sec. The pattern at this time was formed using a shadow mask. The CBP + Ir (ppy) 3 co-deposited film functions as a green light emitting layer.

  When a triplet (phosphorescent) material that emits red light is used as the light emitting layer 4, a CBP and PtOEP co-deposited film having a film thickness of 40 nm is formed by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of CBP and PtOEP materials are put on two Mo sublimation boards, respectively, and the deposition rate is controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And evaporated. The pattern at this time was formed using a shadow mask. The CBP + PtOEP co-deposited film functions as a red light emitting layer.

  In other words, the light emitting layer here refers to a layer that emits light at a wavelength specific to the material by recombination of injected holes and electrons. There is a case where the host material itself forming the light emitting layer emits light, and a case where a dopant material added in a small amount to the host emits light. Specific host materials include distyrylarylene derivatives (DPVBi), silole derivatives having a benzene ring in the skeleton (2PSP), oxodiazole derivatives having a triphenylamine structure at both ends (EM2), and perinone derivatives having a phenanthrene group (P1), oligothiophene derivative (BMA-3T) having a triphenylamine structure at both ends, perylene derivative (tBu-PTC), tris (8-quinolinol) aluminum, polyparaphenylene vinylene derivative, polythiophene derivative, polyparaphenylene derivative Polysilane derivatives and polyacetylene derivatives are desirable. Of course, the material is not limited to these materials, and two or more of these materials may be used in combination. Next, specific dopant materials include quinacridone, coumarin 6, nile red, rubrene, 4- (dicyanomethylene) -2-methyl-6- (para-dimethylaminostyryl) -4H-pyran (DCM), diene. A carbazole derivative is desirable. Of course, the material is not limited to these materials, and two or more of these materials may be used in combination.

The electron transport layer 5 forms an Alq film having a thickness of 20 nm by a vacuum deposition method. At this time,
About 40 mg of the raw material was put on a Mo sublimation board, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The electron transport layer here has a role of transporting electrons and injecting them into the light emitting layer. Therefore, it is desirable that the electron mobility is high. Specifically, tris (8-quinolinol) aluminum, oxadiazole derivatives, silole derivatives, and zinc benzothiazole complexes are desirable. Of course, the material is not limited to these materials, and two or more of these materials may be used in combination.

  The cathode layer 6 was formed by placing about 10 mg and about 5 mg of Al and LiF raw materials in a Mo sublimation boat, respectively, and first depositing LiF with a film thickness of 0.5 nm to 0.01 ± 0.005 nm / sec. . Thereafter, Al having a thickness of 100 nm was vapor-deposited while being controlled at 10.0 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The cathode layer referred to here is preferably a conductive film having a small work function that increases the efficiency of electron injection. Specific examples include a magnesium / silver alloy, an aluminum / lithium alloy, an aluminum / calcium alloy, an aluminum / magnesium alloy, and metallic calcium, but are not limited to these materials. In general, a cathode layer in which aluminum (hereinafter referred to as Al) and lithium fluoride (hereinafter referred to as LiF) are co-deposited, or a cathode layer in which LiF and Al are sequentially deposited after the electron transport layer is used.

  According to the organic light emitting device 12 of this example, the mixed layer 10 used as the hole transport layer 3 forms a stable interface with the anode layer 2, so that the drive voltage increases with the elapsed light emission time is approximately 0V. The organic light emitting device 12 can be manufactured. Therefore, in a display device having a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 and driven by a voltage drive method, The hole transport layer 3 is a mixed layer 10 composed of the hole transport material 8 and the phthalocyanines 11, and the display device of this embodiment can reduce seizure.

  In this embodiment, the display device having a structure in which emitted light is extracted from the substrate 1 side has been described. However, the present invention can also be applied to a display device having a plurality of organic light emitting elements 21 having the structure shown in FIG. In the organic light emitting device 21, the layers shown in this embodiment are formed on the substrate 1 in the order of the cathode layer 6, the electron transport layer 5, the light emitting layer 4, the hole transport layer 3, and the anode layer 2.

  Also in the case of the organic light emitting device 21 shown in FIG. 12, the mixed layer 10 forms a stable interface with the anode layer 2, and thus it is possible to suppress an increase in driving voltage with the elapsed light emission time. Therefore, in a display device that includes a plurality of organic light emitting elements 21 having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and that is driven by a voltage drive system, The hole transport layer 3 is a mixed layer 10 composed of the hole transport material 8 and the phthalocyanines 11, and the display device of this embodiment can reduce seizure.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  In the present embodiment, the display device that emits white light by combining the light emission colors of the light emitting layer 4 is also suitable as an illumination device, and particularly suitable for a backlight illumination device in a liquid crystal display device.

  Embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, the structure of the organic light emitting element 12 in a display device driven by a voltage driving method will be described with reference to FIGS. The organic light-emitting element 12 described in this embodiment is an organic light-emitting element having a structure in which emitted light is extracted from the substrate 1 side.

  FIG. 1 is a cross-sectional view showing the organic light emitting device of this example. In FIG. 1, the organic light emitting device 12 includes an anode layer 2 as a lower electrode, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 as an upper electrode on a substrate 1. The hole transport layer 3 is a two-layered hole transport layer 17 made of a hole transport material 8 and a phthalocyanine 11 and has a structure characterized in that

  The substrate 1 is made of, for example, a transparent material such as quartz, glass plate, polyester, polymethyl methacrylate, polycarbonate, polysulfone, or other plastic film or sheet.

In this embodiment, the anode layer 2 of the organic light emitting element 12 formed on the substrate 1 is, for example, indium tin oxide (ITO), SnO ₂ , which is a transparent conductive material, or a film thickness of 50.
About 1 nm of gold (Au) is formed on one surface of the substrate 1 by sputtering, vacuum deposition or the like.

On the anode layer 2, a hole transport layer 13 having a two-layer structure made of the hole transport material 8 and the phthalocyanines 11 shown in FIG. 8 is formed as the hole transport layer 3.

  The hole transport layer 13 forms a two-layer structure film of a hole transport material 8 and a metal oxide material 9 having a film thickness of 50 nm by a vacuum deposition method.

  As the phthalocyanines 11, a layer of 3 nm thick phthalocyanines 11 was formed by vacuum deposition using copper phthalocyanine (CuPc). The work function of copper phthalocyanine is 5.5 eV. At this time, about 40 mg of copper phthalocyanine is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec.

  The hole transporting material 8 is a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film) having a film thickness of 47 nm by vacuum deposition. A layer of hole transport material 8 was formed. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the vapor deposition rate to 0.15 ± 0.05 nm / sec.

The pattern at this time was formed using a shadow mask. The film thickness of the hole transport layer 13 is not limited to 50 nm shown in this embodiment. Further, the thickness of the metal oxide material 9 is not limited to 3 nm, and the thickness of the hole transport material 8 is not limited to 47 nm. The film thickness ratio between the hole transport material 8 and the copper phthalocyanine 11 of the hole transport layer 13 may be an arbitrary film thickness ratio. Further, as described in Example 2, the hole transport layer 17 having a two-layer structure may be formed by using a technique for controlling the deposition of the hole transport material 8 copper phthalocyanine 11.

  Here, the light emitting layer 4 includes red, green, and blue light emitting materials. In this embodiment, any light emitting material may be used. A triplet material may be used.

  When a light emitting material emitting blue light was used as the light emitting layer 4, a 40 nm thick distyrylarylene derivative film (hereinafter abbreviated as DPVBi) was formed by vacuum deposition. About 40 mg of each DPVBi raw material was put into a Mo sublimation boat, and the vapor deposition rate was controlled to 0.40 ± 0.05 nm / sec. The pattern at this time is formed using a shadow mask.

When a light emitting material that emits green light is used as the light emitting layer 4, a co-deposited film of tris (8-quinolinol) aluminum and quinacridone having a film thickness of 20 nm (hereinafter referred to as Alq and Qc, respectively) by a binary simultaneous vacuum deposition method. .). Alq on two Mo sublimation boards
About 40 mg and about 10 mg of Qc raw materials were added, respectively, and the vapor deposition rates were controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. The pattern at this time is formed using a shadow mask. The Alq + Qc co-evaporated film functions as a green light emitting layer.

  When a light emitting material that emits red light is used as the light emitting layer 4, a 40 nm-thick Alq and Nile Red co-deposited film (hereinafter abbreviated as Nr) was formed by a binary simultaneous vacuum deposition method. About 10 mg and about 5 mg of Alq and Nr raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. Vapor deposited. The pattern at this time is formed using a shadow mask.

  When a triplet (phosphorescent) material that emits green light is used as the light-emitting layer 4, a 40 nm-thick CBP and iridium complex (Ir (ppy) 3) co-deposited film is formed by a binary simultaneous vacuum deposition method. . Two Mo sublimation boards were charged with about 40 mg and about 10 mg of CBP and Ir (ppy) 3 raw materials, respectively, and the deposition rates were 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm, respectively. Vapor deposition was controlled at / sec. The pattern at this time was formed using a shadow mask. The CBP + Ir (ppy) 3 co-deposited film functions as a green light emitting layer.

  When a triplet (phosphorescent) material that emits red light is used as the light emitting layer 4, a CBP and PtOEP co-deposited film having a film thickness of 40 nm is formed by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of CBP and PtOEP materials are put on two Mo sublimation boards, respectively, and the deposition rate is controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And evaporated. The pattern at this time was formed using a shadow mask. The CBP + PtOEP co-deposited film functions as a red light emitting layer.

The electron transport layer 5 forms an Alq film having a thickness of 20 nm by a vacuum deposition method. At this time,
About 40 mg of the raw material was put on a Mo sublimation board, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The cathode layer 6 was formed by placing about 10 mg and about 5 mg of Al and LiF raw materials in a Mo sublimation boat, respectively, and first depositing LiF with a film thickness of 0.5 nm to 0.01 ± 0.005 nm / sec. . Thereafter, Al having a thickness of 100 nm was vapor-deposited while being controlled at 10.0 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

According to the organic light emitting device 12 of this example, the hole transport layer 17 used as the hole transport layer 3 forms a stable interface with the anode layer 2, so that the drive voltage increase with the elapsed light emission time is almost 0V. The organic light emitting device 12 can be manufactured. Therefore, in a display device having a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 and driven by a voltage drive method, The hole transport layer 3 is a hole transport layer 17 having a two-layer structure made of a hole transport material 8 and a phthalocyanine 11, and the display device of this embodiment can reduce image sticking.

  In this embodiment, the display device having a structure in which emitted light is extracted from the substrate 1 side has been described. However, the present invention can also be applied to a display device having a plurality of organic light emitting elements 21 having the structure shown in FIG. The organic light-emitting element 21 includes a cathode layer 6 serving as a lower electrode, an electron transport layer 5, a light-emitting layer 4, a hole transport layer 3, and an anode layer serving as an upper electrode. Form in order of 2.

  Also in the case of the organic light emitting device 21 shown in FIG. 12, the hole transport layer 17 forms a stable interface with the anode layer 2, so that it is possible to suppress an increase in driving voltage with the elapsed light emission time. Therefore, in a display device that includes a plurality of organic light emitting elements 21 having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and that is driven by a voltage drive system, The hole transport layer 3 is a hole transport layer 17 having a two-layer structure made of a hole transport material 8 and a phthalocyanine 11, and the display device of this embodiment can reduce image sticking.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  In the present embodiment, the display device that emits white light by combining the light emission colors of the light emitting layer 4 is also suitable as an illumination device, and particularly suitable for a backlight illumination device in a liquid crystal display device.

  Embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, the structure of the organic light emitting element 12 in a display device driven by a voltage driving method will be described with reference to FIGS. The organic light-emitting element 12 described in this embodiment is an organic light-emitting element having a structure in which emitted light is extracted from the substrate 1 side.

  FIG. 1 is a cross-sectional view showing the organic light emitting device of this example. In FIG. 1, the organic light emitting device 12 includes an anode layer 2 as a lower electrode, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 as an upper electrode on a substrate 1. The hole transport layer 3 is a two-layered hole transport layer 18 composed of a hole transport material 8 and a mixed layer 10. Further, the organic light emitting device 12 shown in this embodiment is characterized in that the hole transport material 8 of the hole transport layer 18 is disposed on the light emitting layer 4 side.

  The substrate 1 is made of, for example, a transparent material such as quartz, glass plate, polyester, polymethyl methacrylate, polycarbonate, polysulfone, or other plastic film or sheet.

In this embodiment, the anode layer 2 of the organic light emitting element 12 formed on the substrate 1 is, for example, indium tin oxide (ITO), SnO ₂ , which is a transparent conductive material, or a film thickness of 50.
About 1 nm of gold (Au) is formed on one surface of the substrate 1 by sputtering, vacuum deposition or the like.

  On the anode layer 2, a hole transport layer 18 having a two-layer structure composed of the hole transport material 8 and the mixed layer 10 shown in FIG. 9 is formed as the hole transport layer 3.

  The hole transport layer 18 forms a two-layer structure film composed of the hole transport material 8 having a thickness of 50 nm and the mixed layer 10 by vacuum deposition.

  The mixed layer 10 formed on the anode layer 2 is formed with a 10 nm-thickness hole transport material 8 and a phthalocyanine 11 co-deposited film by a binary simultaneous vacuum deposition method.

As the hole transport material 8 used for the mixed layer 10, a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film) was used. About 60 mg of α-NPD is put on a Mo sublimation board, and the formation rate of α-NPD film is 0.15 ± 0.05.
Vapor deposition is controlled at nm / sec.

  As the phthalocyanines 11 used in the mixed layer 10, copper phthalocyanine (CuPc) was used. The work function of copper phthalocyanine is 5.2 eV. At this time, about 40 mg of copper phthalocyanine is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec.

The pattern at this time was formed using a shadow mask. In forming the mixed layer 10, the vapor transport rate of the hole transport material 8 and the phthalocyanines 11 was co-evaporated at 1: 1, but the present invention is not limited to this. Further, the deposition rate of the hole transport material 8 and the phthalocyanines 11 is not limited to a constant value. For example, the deposition rate is changed in the course of forming the film thickness of the arbitrary mixed layer 10, for example, the phthalocyanines 11 on the anode layer 2 side. The concentration of phthalocyanines 11 on the light emitting layer 4 side may be low. Conversely, the concentration of the phthalocyanines 11 on the anode layer side may be low and the concentration of the phthalocyanines 11 on the light emitting layer 4 side may be high. Further, the concentration distribution of the phthalocyanines 11 or the concentration distribution of the hole transport material 8 in the mixed layer 10 is not constant and may be arbitrarily changed. The film thickness of the mixed layer 10 is not limited to 10 nm shown in this embodiment.

  The hole transport material 8 formed on the mixed layer 10 is a vacuum using a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film). A 40 nm thick hole transport material 8 layer was formed by vapor deposition. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the deposition rate to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The film thickness of the hole transport layer 18 is not limited to 50 nm shown in this embodiment. The film thickness of the mixed layer 7 is not limited to 10 nm, and the film thickness of the hole transport material 8 is not limited to 40 nm. The film thickness ratio between the hole transport material 8 and the mixed layer 10 of the hole transport layer 18 may be an arbitrary film thickness ratio. The hole transport material 8 of the hole transport layer 18 is in contact with the light emitting layer 4 to be formed next.

  Here, the light emitting layer 4 includes red, green, and blue light emitting materials. In this embodiment, any light emitting material may be used. A triplet material may be used.

  When a light emitting material emitting blue light was used as the light emitting layer 4, a 40 nm thick distyrylarylene derivative film (hereinafter abbreviated as DPVBi) was formed by vacuum deposition. About 40 mg of each DPVBi raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled at 0.40 ± 0.05 nm / sec. The pattern at this time is formed using a shadow mask.

When a light emitting material that emits green light is used as the light emitting layer 4, a co-deposited film of tris (8-quinolinol) aluminum and quinacridone having a film thickness of 20 nm (hereinafter referred to as Alq and Qc, respectively) by a binary simultaneous vacuum deposition method. .). Alq on two Mo sublimation boards
About 40 mg and about 10 mg of Qc raw materials were added, respectively, and the vapor deposition rates were controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. The pattern at this time is formed using a shadow mask. The Alq + Qc co-evaporated film functions as a green light emitting layer.

  When a light emitting material that emits red light is used as the light emitting layer 4, a 40 nm-thick Alq and Nile Red co-deposited film (hereinafter abbreviated as Nr) was formed by a binary simultaneous vacuum deposition method. About 10 mg and about 5 mg of Alq and Nr raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. Vapor deposited. The pattern at this time is formed using a shadow mask.

  When a triplet (phosphorescent) material that emits green light is used as the light-emitting layer 4, a 40 nm-thick CBP and iridium complex (Ir (ppy) 3) co-deposited film is formed by a binary simultaneous vacuum deposition method. . Two Mo sublimation boards were charged with about 40 mg and about 10 mg of CBP and Ir (ppy) 3 raw materials, respectively, and the deposition rates were 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm, respectively. Vapor deposition was controlled at / sec. The pattern at this time was formed using a shadow mask. The CBP + Ir (ppy) 3 co-deposited film functions as a green light emitting layer.

  When a triplet (phosphorescent) material that emits red light is used as the light emitting layer 4, a CBP and PtOEP co-deposited film having a film thickness of 40 nm is formed by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of CBP and PtOEP materials are put on two Mo sublimation boards, respectively, and the deposition rate is controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And evaporated. The pattern at this time was formed using a shadow mask. The CBP + PtOEP co-deposited film functions as a red light emitting layer.

The electron transport layer 5 forms an Alq film having a thickness of 20 nm by a vacuum deposition method. At this time,
About 40 mg of the raw material was put on a Mo sublimation board, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The cathode layer 6 was formed by placing about 10 mg and about 5 mg of Al and LiF raw materials in a Mo sublimation boat, respectively, and first depositing LiF with a film thickness of 0.5 nm to 0.01 ± 0.005 nm / sec. . Thereafter, Al having a thickness of 100 nm was vapor-deposited while being controlled at 10.0 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  According to the organic light emitting device 12 of this example, the hole transport layer 18 used as the hole transport layer 3 forms a stable interface with the anode layer 2, so that the drive voltage increase with the elapsed light emission time is almost 0V. The organic light emitting device 12 can be manufactured. Therefore, in a display device having a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 and driven by a voltage drive method, The hole transport layer 3 is a hole transport layer 18 having a two-layer structure composed of a hole transport material 8 and a mixed layer 10. The display device of this embodiment can reduce image sticking.

  In this embodiment, the display device having a structure in which emitted light is extracted from the substrate 1 side has been described. However, the present invention can also be applied to a display device having a plurality of organic light emitting elements 21 having the structure shown in FIG. In the organic light emitting device 21, the layers shown in this embodiment are formed on the substrate 1 in the order of the cathode layer 6, the electron transport layer 5, the light emitting layer 4, the hole transport layer 3, and the anode layer 2.

  Also in the case of the organic light emitting device 21 shown in FIG. 12, the hole transport layer 18 forms a stable interface with the anode layer 2, and therefore it is possible to suppress an increase in driving voltage with the elapsed light emission time. Therefore, in a display device that includes a plurality of organic light emitting elements 21 having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and that is driven by a voltage drive system, The hole transport layer 3 is a hole transport layer 18 having a two-layer structure composed of a hole transport material 8 and a mixed layer 10. The display device of this embodiment can reduce image sticking.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  In the present embodiment, the display device that emits white light by combining the light emission colors of the light emitting layer 4 is also suitable as a lighting device as in the other embodiments described above, and particularly suitable for a backlight lighting device in a liquid crystal display device. It is.

  Embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, the structure of the organic light emitting element 12 in a display device driven by a voltage driving method will be described with reference to FIGS. The organic light-emitting element 12 described in this embodiment is an organic light-emitting element having a structure in which emitted light is extracted from the substrate 1 side.

  FIG. 1 is a cross-sectional view showing the organic light emitting device of this example. In FIG. 1, the organic light emitting device 12 includes an anode layer 2 as a lower electrode, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 as an upper electrode on a substrate 1. The hole transport layer 3 is a three-layered hole transport layer 19 composed of a hole transport material 8, a mixed layer 10 and a phthalocyanine 11, and has a structure characterized in that Further, the organic light emitting device 12 shown in this embodiment is characterized in that the hole transport material 8 of the hole transport layer 19 is disposed on the light emitting layer 4 side.

  The substrate 1 is made of, for example, a transparent material such as quartz, glass plate, polyester, polymethyl methacrylate, polycarbonate, polysulfone, or other plastic film or sheet.

In this embodiment, the anode layer 2 of the organic light emitting element 12 formed on the substrate 1 is, for example, indium tin oxide (ITO), SnO ₂ , which is a transparent conductive material, or a film thickness of 50.
About 1 nm of gold (Au) is formed on one surface of the substrate 1 by sputtering, vacuum deposition or the like.

  On the anode layer 2, a hole transport layer 19 having a three-layer structure including the hole transport material 8, the mixed layer 10, and the phthalocyanines 11 shown in FIG. 10 is formed as the hole transport layer 3.

  The hole transport layer 19 forms a three-layer structure film composed of a hole transport material 8 having a film thickness of 50 nm, a mixed layer 10 and phthalocyanines 11 by a vacuum deposition method.

  Copper phthalocyanine (CuPc) was used as the phthalocyanines 11 formed on the anode layer 2. The work function of copper phthalocyanine is 5.2 eV. At this time, about 40 mg of copper phthalocyanine is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec. In this embodiment, the film thickness of the phthalocyanines 11 is 3 nm.

  The mixed layer 10 is formed of a co-deposited film of a 7 nm-thick hole transport material 8 and a phthalocyanine 11 by a binary simultaneous vacuum deposition method.

  As the hole transport material 8 forming the mixed layer 10, a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as α-NPD film) was used. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the vapor deposition rate to 0.15 ± 0.05 nm / sec.

  Copper phthalocyanine (CuPc) was used as the phthalocyanines 11 forming the mixed layer 10. The work function of copper phthalocyanine is 5.2 eV. At this time, about 40 mg of copper phthalocyanine is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec.

  The pattern at this time was formed using a shadow mask. In forming the mixed layer 10, the vapor transport rate of the hole transport material 8 and the phthalocyanines 11 was co-evaporated at 1: 1, but the present invention is not limited to this. Further, the deposition rate of the hole transport material 8 and the phthalocyanines 11 is not limited to a constant value. For example, the deposition rate is changed in the course of forming the film thickness of the arbitrary mixed layer 10, for example, the phthalocyanines 11 on the anode layer 2 side. The concentration of phthalocyanines 11 on the light emitting layer 4 side may be low. Conversely, the concentration of the phthalocyanines 11 on the anode layer 2 side may be low and the concentration of the phthalocyanines 11 on the light emitting layer 4 side may be high. Further, the concentration distribution of the phthalocyanines 11 or the concentration distribution of the hole transport material 8 in the mixed layer 10 is not constant and may be arbitrarily changed. The film thickness of the mixed layer 10 is not limited to 7 nm shown in this embodiment.

  The hole transport material 8 formed on the mixed layer 10 is a vacuum using a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film). A 40 nm thick hole transport material 8 layer was formed by vapor deposition. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the deposition rate to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The film thickness of the hole transport layer 19 is not limited to 50 nm shown in this embodiment. The thickness of the mixed layer 10 is not limited to 7 nm, the thickness of the hole transport material 8 is 40 nm, and the thickness of the phthalocyanines 11 is not limited to 3 nm. The film thickness ratio of the hole transport material 8, the mixed layer 10, and the phthalocyanines 11 of the hole transport layer 19 may be an arbitrary film thickness ratio. The hole transport material 8 of the hole transport layer 19 is in contact with the light emitting layer 4 to be formed next.

  Here, the light emitting layer 4 includes red, green, and blue light emitting materials. In this embodiment, any light emitting material may be used. A triplet material may be used.

  When a light emitting material emitting blue light was used as the light emitting layer 4, a 40 nm thick distyrylarylene derivative film (hereinafter abbreviated as DPVBi) was formed by vacuum deposition. About 40 mg of each DPVBi raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled at 0.40 ± 0.05 nm / sec. The pattern at this time is formed using a shadow mask.

When a light emitting material that emits green light is used as the light emitting layer 4, a co-deposited film of tris (8-quinolinol) aluminum and quinacridone having a film thickness of 20 nm (hereinafter referred to as Alq and Qc, respectively) by a binary simultaneous vacuum deposition method. .). Alq on two Mo sublimation boards
About 40 mg and about 10 mg of Qc raw materials were added, respectively, and the vapor deposition rates were controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. The pattern at this time is formed using a shadow mask. The Alq + Qc co-evaporated film functions as a green light emitting layer.

  When a light emitting material that emits red light is used as the light emitting layer 4, a 40 nm-thick Alq and Nile Red co-deposited film (hereinafter abbreviated as Nr) was formed by a binary simultaneous vacuum deposition method. About 10 mg and about 5 mg of Alq and Nr raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. Vapor deposited. The pattern at this time is formed using a shadow mask.

  When a triplet (phosphorescent) material that emits green light is used as the light-emitting layer 4, a 40 nm-thick CBP and iridium complex (Ir (ppy) 3) co-deposited film is formed by a binary simultaneous vacuum deposition method. . Two Mo sublimation boards were charged with about 40 mg and about 10 mg of CBP and Ir (ppy) 3 raw materials, respectively, and the deposition rates were 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm, respectively. Vapor deposition was controlled at / sec. The pattern at this time was formed using a shadow mask. The CBP + Ir (ppy) 3 co-deposited film functions as a green light emitting layer.

  When a triplet (phosphorescent) material that emits red light is used as the light emitting layer 4, a CBP and PtOEP co-deposited film having a film thickness of 40 nm is formed by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of CBP and PtOEP materials are put on two Mo sublimation boards, respectively, and the deposition rate is controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And evaporated. The pattern at this time was formed using a shadow mask. The CBP + PtOEP co-deposited film functions as a red light emitting layer.

The electron transport layer 5 forms an Alq film having a thickness of 20 nm by a vacuum deposition method. At this time,
About 40 mg of the raw material was put on a Mo sublimation board, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The cathode layer 6 was formed by placing about 10 mg and about 5 mg of Al and LiF raw materials in a Mo sublimation boat, respectively, and first depositing LiF with a film thickness of 0.5 nm to 0.01 ± 0.005 nm / sec. . Thereafter, Al having a thickness of 100 nm was vapor-deposited while being controlled at 10.0 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  According to the organic light emitting device 12 of this example, the hole transport layer 19 used as the hole transport layer 3 forms a stable interface with the anode layer 2, so that the drive voltage increase with the elapsed light emission time is almost 0V. The organic light emitting device 12 can be manufactured. Therefore, in a display device having a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 and driven by a voltage drive method, The hole transport layer 3 is a hole transport layer 19 having a three-layer structure composed of a hole transport material 8, a mixed layer 7, and a phthalocyanine 11, and the display device of this embodiment reduces seizure. Can do.

  In this embodiment, the display device having a structure in which emitted light is extracted from the substrate 1 side has been described. However, the present invention can also be applied to a display device having a plurality of organic light emitting elements 21 having the structure shown in FIG. In the organic light emitting device 21, the layers shown in this embodiment are formed on the substrate 1 in the order of the cathode layer 6, the electron transport layer 5, the light emitting layer 4, the hole transport layer 3, and the anode layer 2.

  Also in the case of the organic light emitting device 21 shown in FIG. 12, the hole transport layer 19 forms a stable interface with the anode layer 2, and thus it is possible to suppress an increase in driving voltage with the elapsed light emission time. Therefore, in a display device that includes a plurality of organic light emitting elements 21 having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and that is driven by a voltage drive system, The hole transport layer 3 is a hole transport layer 19 having a three-layer structure composed of a hole transport material 8, a mixed layer 7, and a phthalocyanine 11, and the display device of this embodiment reduces seizure. Can do.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  In the present embodiment, the display device that emits white light by combining the light emission colors of the light emitting layer 4 is also suitable as a lighting device as in the other embodiments described above, and particularly suitable for a backlight lighting device in a liquid crystal display device. It is.

  Embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, the structure of the organic light emitting element 12 in a display device driven by a voltage driving method will be described with reference to FIGS. The organic light-emitting element 12 described in this embodiment is an organic light-emitting element having a structure in which emitted light is extracted from the substrate 1 side.

  FIG. 1 is a cross-sectional view showing the organic light emitting device of this example. In FIG. 1, the organic light emitting device 12 includes an anode layer 2 as a lower electrode, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 as an upper electrode on a substrate 1. The hole transport layer 3 is a three-layered hole transport layer 20 composed of a hole transport material 8, a phthalocyanine 11 and a mixed layer 10. In addition, the organic light emitting device 12 shown in this example is characterized in that the hole transport material 8 of the hole transport layer 20 is disposed on the light emitting layer 4 side.

  The substrate 1 is made of, for example, a transparent material such as quartz, glass plate, polyester, polymethyl methacrylate, polycarbonate, polysulfone, or other plastic film or sheet.

In this embodiment, the anode layer 2 of the organic light emitting element 12 formed on the substrate 1 is, for example, indium tin oxide (ITO), SnO ₂ , which is a transparent conductive material, or a film thickness of 50.
About 1 nm of gold (Au) is formed on one surface of the substrate 1 by sputtering, vacuum deposition or the like.

  On the anode layer 2, a hole transport layer 20 having a three-layer structure including the hole transport material 8, the phthalocyanines 11 and the mixed layer 10 shown in FIG. 11 is formed as the hole transport layer 3.

  The hole transport layer 20 forms a three-layer structure film composed of the hole transport material 8 having a film thickness of 50 nm, the phthalocyanines 11 and the mixed layer 10 by a vacuum deposition method.

  The mixed layer 10 formed on the anode layer 2 is formed of a co-deposited film of a 7 nm-thick hole transport material 8 and a phthalocyanine 11 by a binary simultaneous vacuum deposition method.

  As the hole transport material 8 forming the mixed layer 10, a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as α-NPD film) was used. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the vapor deposition rate to 0.15 ± 0.05 nm / sec.

  Copper phthalocyanine (CuPc) was used as the phthalocyanines 11 forming the mixed layer 10. The work function of copper phthalocyanine is 5.2 eV. At this time, about 40 mg of copper phthalocyanine is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec.

  The pattern at this time was formed using a shadow mask. In forming the mixed layer 10, the vapor transport rate of the hole transport material 8 and the phthalocyanines 11 was co-evaporated at 1: 1, but the present invention is not limited to this. Further, the deposition rate of the hole transport material 8 and the phthalocyanines 11 is not limited to a constant value. For example, the deposition rate is changed in the course of forming the film thickness of the arbitrary mixed layer 10, for example, the phthalocyanines 11 on the anode layer 2 side. The concentration of phthalocyanines 11 on the light emitting layer 4 side may be low. Conversely, the concentration of the phthalocyanines 11 on the anode layer side may be low and the concentration of the phthalocyanines 11 on the light emitting layer 4 side may be high. Further, the concentration distribution of the phthalocyanines 11 or the concentration distribution of the hole transport material 8 in the mixed layer 10 is not constant and may be arbitrarily changed. The film thickness of the mixed layer 10 is not limited to 7 nm shown in this embodiment.

  As the phthalocyanines 11 formed on the mixed layer 10, copper phthalocyanine (CuPc) was used. The work function of copper phthalocyanine is 5.2 eV. At this time, about 40 mg of copper phthalocyanine is put on the Mo sublimation board, and the deposition rate is controlled to 0.15 ± 0.05 nm / sec. The film thickness of the phthalocyanines 11 shown in this example is 3 nm.

  The hole transport material 8 formed on the phthalocyanines 11 is a vacuum using a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter referred to as an α-NPD film). A 40 nm thick hole transport material 8 layer was formed by vapor deposition. About 60 mg of α-NPD is put on a Mo sublimation board, and the α-NPD film is formed by controlling the deposition rate to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The film thickness of the hole transport layer 20 is not limited to 50 nm shown in this embodiment. The thickness of the mixed layer 10 is not limited to 7 nm, the thickness of the hole transport material 8 is 40 nm, and the thickness of the phthalocyanines 11 is not limited to 3 nm. The film thickness ratio of the hole transport material 8, the mixed layer 10, and the phthalocyanines 11 of the hole transport layer 20 may be an arbitrary film thickness ratio. The hole transport material 8 of the hole transport layer 20 is in contact with the light emitting layer 4 to be formed next.

  Here, the light emitting layer 4 includes red, green, and blue light emitting materials. In this embodiment, any light emitting material may be used. A triplet material may be used.

  When a light emitting material emitting blue light was used as the light emitting layer 4, a 40 nm thick distyrylarylene derivative film (hereinafter abbreviated as DPVBi) was formed by vacuum deposition. About 40 mg of each DPVBi raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled at 0.40 ± 0.05 nm / sec. The pattern at this time is formed using a shadow mask.

When a light emitting material that emits green light is used as the light emitting layer 4, a co-deposited film of tris (8-quinolinol) aluminum and quinacridone having a film thickness of 20 nm (hereinafter referred to as Alq and Qc, respectively) by a binary simultaneous vacuum deposition method. .). Alq on two Mo sublimation boards
About 40 mg and about 10 mg of Qc raw materials were added, respectively, and the vapor deposition rates were controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. The pattern at this time is formed using a shadow mask. The Alq + Qc co-evaporated film functions as a green light emitting layer.

  When a light emitting material that emits red light is used as the light emitting layer 4, a 40 nm-thick Alq and Nile Red co-deposited film (hereinafter abbreviated as Nr) was formed by a binary simultaneous vacuum deposition method. About 10 mg and about 5 mg of Alq and Nr raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. Vapor deposited. The pattern at this time is formed using a shadow mask.

  When a triplet (phosphorescent) material that emits green light is used as the light-emitting layer 4, a 40 nm-thick CBP and iridium complex (Ir (ppy) 3) co-deposited film is formed by a binary simultaneous vacuum deposition method. . Two Mo sublimation boards were charged with about 40 mg and about 10 mg of CBP and Ir (ppy) 3 raw materials, respectively, and the deposition rates were 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm, respectively. Vapor deposition was controlled at / sec. The pattern at this time was formed using a shadow mask. The CBP + Ir (ppy) 3 co-deposited film functions as a green light emitting layer.

  When a triplet (phosphorescent) material that emits red light is used as the light emitting layer 4, a CBP and PtOEP co-deposited film having a film thickness of 40 nm is formed by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of CBP and PtOEP materials are put on two Mo sublimation boards, respectively, and the deposition rate is controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And evaporated. The pattern at this time was formed using a shadow mask. The CBP + PtOEP co-deposited film functions as a red light emitting layer.

The electron transport layer 5 forms an Alq film having a thickness of 20 nm by a vacuum deposition method. At this time,
About 40 mg of the raw material was put on a Mo sublimation board, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

  The cathode layer 6 was formed by placing about 10 mg and about 5 mg of Al and LiF raw materials in a Mo sublimation boat, respectively, and first depositing LiF with a film thickness of 0.5 nm to 0.01 ± 0.005 nm / sec. . Thereafter, Al having a thickness of 100 nm was vapor-deposited while being controlled at 10.0 ± 0.05 nm / sec. The pattern at this time was formed using a shadow mask.

According to the organic light emitting device 12 of this example, the hole transport layer 20 used as the hole transport layer 3 forms a stable interface with the anode layer 2, so that the drive voltage increase with the elapsed light emission time is almost 0V. The organic light emitting device 12 can be manufactured. Therefore, in a display device having a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6 and driven by a voltage drive method, The hole transport layer 3 is a hole transport layer 20 having a three-layer structure composed of a hole transport material 8, a phthalocyanine 11 and a mixed layer 10, and the display device of this embodiment reduces seizure. Can do. In this embodiment, a display device having a structure in which emitted light is extracted from the substrate 1 side has been described. However, the present invention can be applied to a display device having a plurality of organic light emitting elements 21 having a structure shown in FIG. In the organic light emitting device 21, the layers shown in this embodiment are formed on the substrate 1 in the order of the cathode layer 6, the electron transport layer 5, the light emitting layer 4, the hole transport layer 3, and the anode layer 2. Also in the case of the organic light emitting device 21 shown in FIG. 12, the hole transport layer 20 forms a stable interface with the anode layer 2, so that it is possible to suppress an increase in driving voltage with the elapsed light emission time. Therefore, in a display device that includes a plurality of organic light emitting elements 21 having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and that is driven by a voltage drive system, The hole transport layer 3 is a hole transport layer 20 having a three-layer structure composed of a hole transport material 8, a phthalocyanine 11 and a mixed layer 10, and the display device of this embodiment reduces seizure. Can do.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  In the present embodiment, the display device that emits white light by combining the light emission colors of the light emitting layer 4 is also suitable as a lighting device as in the other embodiments described above, and particularly suitable for a backlight lighting device in a liquid crystal display device. It is.

  Hereinafter, embodiments of the display device of the present invention will be described with reference to FIGS. 13 is a cross-sectional view taken along the line AA ′ shown in FIG. FIG. 14 is a plan view of a pixel region in the display device of this embodiment.

  A feature of the display device in this embodiment is that it has a plurality of pixels and a thin film transistor for driving the pixels, and in the active display device driven by a voltage driving method, each of the plurality of pixels has an organic light emitting element. The organic light-emitting element comprises an anode layer serving as a lower electrode, a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode layer serving as an upper electrode on a substrate. The organic light-emitting layer extracts light emitted from the organic light-emitting layer, and the anode layer is connected to an auxiliary electrode made of a low-resistance material. The organic light-emitting element includes the cathode layer, the electron transport layer, the light-emitting layer, The hole transport layer is formed in the order of the anode layer, and the hole transport layer is composed of a hole transport material and a metal oxide material or a phthalocyanine. With light emitting element 12 And wherein the Rukoto.

  Hereinafter, a method for manufacturing the organic light emitting display device of this embodiment will be described.

An amorphous silicon (a-Si) film having a thickness of 50 nm is formed on the glass substrate 116 by using a low pressure chemical vapor deposition method (LPCVD method). Next, the entire surface of the film was laser annealed. Thereby, a-Si was crystallized to become polycrystalline silicon (p-Si). Next, p-
The Si film was patterned by dry etching to form the active layer 103 of the first transistor 101, the active layer 103 ′ of the second transistor 102, and the capacitor lower electrode 105.

Next, a 100 nm thick SiO ₂ film was formed as the gate insulating film 117 using plasma enhanced chemical vapor deposition (PECVD).

  Next, a TiW film having a thickness of 50 nm was formed as the gate electrodes 107 and 107 ′ by sputtering and patterned. In addition, the scanning line 106 and the capacitor upper electrode 108 were also patterned.

  Next, N ions were implanted into the patterned p-Si layer from above the gate insulating film 117 by ion implantation. N ions are not implanted into the region having the gate electrode on the upper portion, and become active layers 103 and 103 '.

Next, the substrate 116 was subjected to a heat activation process in an inert N ₂ atmosphere so that doping was effectively performed. A silicon nitride (SiN _x ) film was formed thereon as the first interlayer insulating layer 118. The film thickness is 200 nm.

  Next, contact holes were formed in the gate insulating film 117 and the first interlayer insulating film 118 above both ends of the active layers 103 and 103 ′. Further, contact holes were formed in the first interlayer insulating film 118 above the gate electrode 107 ′ of the second transistor. An Al film having a thickness of 500 nm is formed thereon by sputtering. A signal line 109 and a power supply line 110 are formed by a photolithography process. Further, the source electrode 112 and the drain electrode 113 of the first transistor 101, and the source electrode 112 ′ and the drain electrode 113 ′ of the second transistor 102 are formed.

  The capacitor lower electrode 105 and the drain electrode 113 of the first transistor 101 are connected. In addition, the source electrode 112 of the first transistor 101 and the signal line 109 are connected. Further, the drain electrode 113 of the first transistor is connected to the gate electrode 107 ′ of the second transistor. Further, the drain electrode 113 ′ of the second transistor is connected to the power supply line 110. Further, the capacitor upper electrode 108 is connected to the power supply line 110.

Next, a SiN _x film was formed as the second interlayer insulating film 119. The film thickness is 500 nm. A contact hole is provided on the drain electrode 113 'of the second transistor. A 150-nm-thick Al film is formed thereon using a sputtering method, and a cathode layer 115 is formed using a photolithographic method.

  Next, as the third interlayer insulating film 120, a positive photosensitive protective film (PC452) manufactured by JSR was formed using a spin coating method, and a baking process was performed. The film thickness of the third interlayer insulating film 120 formed of PC452 was 1 μm, and the edge of the cathode layer 115 was covered by 3 μm.

  The glass substrate 116 formed up to the cathode layer 115 was subjected to ultrasonic cleaning for 3 minutes in the order of acetone and pure water. After washing, spin drying was performed.

  Next, the structure of the organic light emitting element that becomes the pixel will be described. On the cathode layer 115, LiF124 was formed to 0.5 nm by vacuum deposition. A shadow mask was used for pattern formation.

  An Alq film having a thickness of 20 nm was formed thereon by vacuum deposition. The Alq film functions as the electron transport layer 123. A shadow mask was used for pattern formation. A co-deposited film of tris (8-quinolinol) aluminum and quinacridone (hereinafter abbreviated as Alq and Qc, respectively) having a film thickness of 20 nm was formed thereon by a binary simultaneous vacuum deposition method. The deposition rate was controlled to 40: 1 for deposition. The Alq + Qc co-evaporated film functions as the light emitting layer 122. A shadow mask was used for pattern formation. For the light emitting layer 122, the light emitting material of the light emitting layer 4 described in Examples 1 to 10 may be used. Next, the hole transport layer described in Examples 1 to 10 is formed as the hole transport layer 121. The hole transport layer 121 functions as a layer that transports holes from the anode layer 125 to the light emitting layer 122. Since the hole transport layer 121 described in Examples 1 to 10 forms a stable interface with the anode layer 125, an increase in driving voltage with the light emission elapsed time can be suppressed to almost 0V.

Next, an In—Zn—O film (hereinafter abbreviated as IZO film) with a thickness of 100 nm was formed by a sputtering method. This film functions as the anode layer 125 and is an amorphous oxide film. The target used was In / (In + Zn) = 0.83. The film forming conditions were an Ar: O ₂ mixed gas atmosphere, a vacuum degree of 1 Pa, and a sputtering output of 0.2 W / cm ² . The anode layer 125 made of an In—ZnO film functioned as an anode, and the transmittance was 80%. Next, a 50 nm thick SiOxNy film was formed by sputtering. The film functions as a protective layer 126.

  Since the organic light emitting element of this embodiment can suppress an increase in driving voltage accompanying the light emission elapsed time to almost 0 V, a display device with less image sticking can be provided.

  You may provide the negative voltage application circuit which applies a negative voltage to the organic light emitting element of the display apparatus of a present Example. A circuit that applies a negative voltage can suppress an increase in the driving voltage of the organic light emitting element by applying a negative voltage of, for example, about −6 V when starting or stopping the display device, for example. . Therefore, a display device with less image sticking can be provided.

  The display layer that emits white light by combining the red, green, and blue light-emitting materials described in Embodiments 1 to 10 as the light emitting layer 122 of this embodiment is also suitable as a lighting device, and displays a color image when combined with a color filter. It is also suitable as a device, and is also suitable as a backlight illumination device in a liquid crystal display device as in the other embodiments described above.

  This embodiment has a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and the plurality of pixels In an active organic light emitting display device having a thin film transistor for driving the pixel, the organic light emitting device 12 is the organic light emitting device 12 having the hole transport layer 3 described in Examples 1 to 10. State.

  FIG. 15 is a configuration diagram of a voltage driven organic EL display according to the twelfth embodiment. Pixels 201 are arranged in a matrix in the display area 202, and a vertical wiring group 203 and a horizontal wiring group 204 are connected to the pixels 201. One end of the vertical wiring group 203 is connected to the signal and power supply voltage output circuit 205, and one end of the horizontal wiring group 204 is connected to the vertical scanning circuit 206. In order to simplify the drawing, only 6 pixels are shown in FIG. 15, but in actuality, the number of pixels in this embodiment is 240 pixels (horizontal) × RGB × 320 pixels (vertical). All the pixels in the display area 202 are provided on the same glass substrate.

  Next, the configuration of the pixel 201 will be described.

FIG. 16 is a pixel circuit diagram of the pixel 201. The vertical wiring group 203 includes signal lines 216 and power supply lines 217, and the horizontal wiring group 204 includes reset lines 218 and power control lines 219. Each pixel 201 is provided with an organic light emitting element 12. One end of the organic light emitting element 12 is connected to a common electrode, and the other end is connected to a power supply line 217 via a power control switch 212 and a driving TFT 213. . A reset switch 214 is connected between the gate and drain of the driving TFT 213. The gate of the driving TFT 213 is connected to the signal line 216 via the storage capacitor 215. The reset switch 214 is controlled by a reset line 218, and the power control switch 212 is controlled by a power control line 219.

  Next, the operation of the twelfth embodiment will be described.

  In the pixel 201 selected for writing by the vertical scanning circuit 206, when the power control switch 212 is first turned on, the organic light emitting element 12 is connected to the driving TFT 213, and when the reset switch 214 is further turned on by the reset line 9. The drive TFT 213 and the organic light emitting element 12 diode-connected by the reset switch 214 are connected to the power line 217 by the power control switch 212, and a current flows. Next, when the power control switch 212 is turned off, the drive TFT 213 is turned off when the drain end of the drive TFT 213 reaches the threshold voltage Vth. At this time, a video signal voltage is applied to the signal line 216, and a difference between the video signal voltage and the threshold voltage Vth is input to the storage capacitor 215. Next, when the reset switch 214 is turned off, the signal voltage writing to this pixel is completed. In this manner, signal voltage writing to each pixel is sequentially performed in the first half of the frame period.

  When writing to the pixel is completed, the second half of the frame period is the gradation light emission period of the pixel. During this period, a downward triangular wave voltage is input to the signal line 216. At this time, in a period in which the voltage value of the signal line 216 is smaller than the video signal voltage written earlier, the gate voltage of the driving TFT 213 is the previous threshold voltage Vth, and thus the organic light emitting element 12 is turned on. Accordingly, the lighting time within the second half of the frame period of the organic light emitting element 12 is defined by the magnitude relationship between the video signal voltage value written in advance and the triangular wave voltage applied to the signal line 216. Accordingly, the organic light emitting element 12 is lit in the light emission period corresponding to the video signal voltage, and the luminance gradation can be realized by the voltage driving method.

  A circuit configuration of an organic EL display having such a pixel equivalent circuit and a driving method thereof are described in detail in Japanese Patent Application Laid-Open No. 2003-122301.

  In this embodiment, it is possible to use the organic light emitting element 21 shown in FIG. 12 in place of the organic light emitting element 12, but in this case, since the direction of current is reversed, the n-type and p-type TFTs are used. Needless to say, it is necessary to reverse the polarity and reverse the voltage relationship.

  Since the organic light-emitting element 12 used in this example uses the organic light-emitting element 12 having the hole transport layer 3 described in Examples 1 to 10, a stable interface with the anode layer 2 is formed, so that the light emission elapsed time is reduced. The organic light emitting device 12 that can suppress the accompanying increase in drive voltage can be manufactured.

  Thus, when driven by a voltage drive system, the organic light-emitting element 12 composed of the hole transport layer described in Examples 1 to 10 forms a stable interface with the anode layer 2, and thus is driven with the elapsed light emission time. Since the organic light emitting element 12 capable of suppressing the increase in voltage can be manufactured, a display device with less image sticking can be provided.

  This embodiment has a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and the plurality of pixels In an active organic light emitting display device having a thin film transistor for driving the pixel, the organic light emitting device 12 is the organic light emitting device 12 having the hole transport layer 3 described in Examples 1 to 10. State.

  The configuration diagram of the current driven organic EL display which is the thirteenth embodiment is basically the same as the configuration diagram of the organic EL display in the twelfth embodiment shown in FIG. .

  Hereinafter, the configuration of the pixel 233 in this embodiment will be described.

  FIG. 17 is a pixel circuit diagram of the pixel 233. The pixel 233 is provided with an organic light emitting element 12, one end of the organic light emitting element 12 is connected to a common electrode, and the other end is connected to a power supply line 229 via an AZB switch 222 and a driving TFT (Thin Film-Transistor) 223. It is connected. An AZ switch 224 is connected between the gate and drain of the driving TFT 223, and a storage capacitor 227 is connected between the gate and source. The gate of the driving TFT 223 is connected to the signal line 228 via the offset cancel capacitor 225 and the pixel switch 226. The AZB switch 222 is controlled by an AZB control line 232, the AZ switch 224 is controlled by an AZ control line 231, and the pixel switch 226 is controlled by a gate line 230.

  Next, the operation of this conventional example will be described.

  In the pixel selected for writing, first, the pixel switch 226 is turned on by the gate line 230, and the AZ switch 224 is turned on by the AZ control line 231. At this time, since the AZB switch 222 is on, a current flows from the power supply line 229 to the organic light emitting element 12 via the diode-connected driving TFT 223. Next, when the AZB switch 222 is turned off by the AZB control line 232, the driving TFT 223 is turned off when the drain terminal of the driving TFT 223 reaches the threshold voltage Vth. At this time, a signal voltage of “0 level” is applied to the signal line 228, and the difference between this voltage and the threshold voltage Vth is input to the offset cancel capacitor 225. Next, after the AZ switch 224 is turned off by the AZ control line 231, the video signal voltage is applied to the signal line 228. At this time, a voltage corresponding to the video signal voltage is generated in the threshold voltage Vth at the gate of the driving TFT 223, and this voltage is stored in the storage capacitor 227 when the pixel switch 226 is turned off by the gate line 230. Thereafter, when the AZB switch 222 is turned on, the signal voltage writing to the pixel is completed, and the organic light emitting element 12 continues to emit light at the luminance corresponding to the video signal voltage until the next writing period.

  A circuit configuration of an organic EL display having such a pixel equivalent circuit and a driving method thereof are described in detail in, for example, 1998 SID Digest of Technical Papers, pp. 11-14.

  In this embodiment, it is possible to use the organic light emitting element 21 shown in FIG. 12 in place of the organic light emitting element 12, but in this case, since the direction of the current is reversed, the n-type and p-type TFTs are used. Needless to say, it is necessary to reverse the polarity and reverse the relationship of the voltages.

  Since the organic light-emitting element 12 used in this example uses the organic light-emitting element 12 having the hole transport layer 3 described in Examples 1 to 10, a stable interface with the anode layer 2 is formed, so that the light emission elapsed time is reduced. The organic light emitting device 12 that can suppress the accompanying increase in drive voltage can be manufactured.

  When driving by the current driving method in this way, the organic light emitting device 12 composed of the hole transport layer described in Examples 1 to 10 forms a stable interface with the anode layer 2, so that driving with the elapsed light emission time is performed. Since the organic light emitting element 12 capable of suppressing the increase in voltage can be manufactured, a display device with low power consumption can be provided.

  This example has a plurality of organic light emitting elements 12 each having an anode layer 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a cathode layer 6, and is a simple matrix type organic light emitting device. In the display device, the organic light emitting element 12 is the organic light emitting element 12 having the hole transport layer 3 described in Examples 1 to 10, and the display device is described.

  FIG. 18 is a configuration diagram of a simple matrix type organic EL display which is the fourteenth embodiment. Pixels 241 are arranged in a matrix in the display region 242, and vertical wirings 243 and horizontal wirings 244 are connected to the pixels 241. One end of the vertical wiring 243 is connected to the horizontal signal circuit 245, and one end of the horizontal wiring 244 is connected to the vertical signal circuit 246. In order to simplify the drawing, only 6 pixels are shown in FIG. 18, but the number of pixels in this embodiment is actually 96 pixels (horizontal) × RGB × 96 pixels (vertical). All the pixels in the display area 242 are provided on the same glass substrate.

  Each pixel 241 is provided with the organic light emitting element 12 between the vertical wiring 243 and the horizontal wiring 244.

  Next, the operation of this conventional example will be described.

  The vertical signal circuit 246 sequentially applies drive voltages to the horizontal wiring 244. In accordance with this applied scanning, the horizontal signal circuit 245 inputs a light emission drive voltage or light emission drive current to the vertical wiring 243. At this time, the pixel 241 selected by the vertical signal circuit 246 emits light corresponding to the light emission drive voltage or light emission drive current input by the horizontal signal circuit 245 within the selected period. By repeating this scanning, an image is displayed on the display area 242.

  As described above, the method for driving the simple matrix display device may be a voltage driving method or a current driving method.

  When driven by the voltage drive method, the organic light emitting device 12 composed of the hole transport layer described in Examples 1 to 10 forms a stable interface with the anode layer 2, so that the drive voltage increases with the elapsed light emission time. Since the organic light emitting element 12 that can suppress the above can be manufactured, a display device with less image sticking can be provided.

  Further, when driven by a current driving method, the organic light emitting device 12 composed of the hole transport layer described in Examples 1 to 10 forms a stable interface with the anode layer 2, so that the driving voltage associated with the elapsed light emission time. Since the organic light emitting element 12 that can suppress the increase in the thickness can be manufactured, a display device with low power consumption can be provided.

  Also in this embodiment, the organic light emitting element 21 shown in FIG. 12 can be used in place of the organic light emitting element 12.

  By using the present invention, a thin self-luminous display device with less image sticking can be realized, and it can be used for a display device such as a television or various information terminals, a lighting fixture, or the like.

It is sectional drawing which shows the organic light emitting element of Example 1 of this invention. It is sectional drawing which shows the positive hole transport layer of Example 1 of this invention. It is sectional drawing which shows the positive hole transport layer of Example 2 of this invention. It is sectional drawing which shows the positive hole transport layer of Example 3 of this invention. It is sectional drawing which shows the positive hole transport layer of Example 4 of this invention. It is sectional drawing which shows the positive hole transport layer of Example 5 of this invention. It is sectional drawing which shows the positive hole transport layer of Example 6 of this invention. It is sectional drawing which shows the positive hole transport layer of Example 7 of this invention. It is sectional drawing which shows the positive hole transport layer of Example 8 of this invention. It is sectional drawing which shows the positive hole transport layer of Example 9 of this invention. It is sectional drawing which shows the positive hole transport layer of Example 10 of this invention. It is sectional drawing which shows the organic light emitting element of the structure which takes out emitted light from the opposite side to the board | substrate 1 side. It is sectional drawing which follows AA 'shown in FIG. It is a top view of the pixel area | region which shows Example 13 of this invention. It is a display block diagram of Example 12 of this invention. It is a pixel circuit diagram of Example 12 of the present invention. It is a pixel circuit diagram of Example 13 of the present invention. It is a display block diagram of Example 14 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,116 ... Board | substrate, 2,125 ... Anode layer, 3,121 ... Hole transport layer, 4,122 ... Light emitting layer, 5,123 ... Electron transport layer, 6,115 ... Cathode layer, 7 ... Mixed layer, 8 DESCRIPTION OF SYMBOLS ... Hole transport material, 9 ... Metal oxide material, 12 ... Organic light emitting element, 101 ... 1st transistor, 102 ... 2nd transistor, 103 ... Active layer, 105 ... Capacitor lower electrode, 106 ... Scan line, 107 ... Gate electrode 108, capacitor upper electrode, 109, 216, 228 ... signal line, 112, 112 '... source electrode, 113 ... drain electrode, 117 ... gate insulating film, 118 ... first interlayer insulating film, 119 ... second interlayer insulating film , 120 ... third interlayer insulating film, 124 ... LiF, 126 ... protective layer, 127 ... buffer layer, 128 ... auxiliary electrode, 136 ... flattening layer, 141, 201, 233 ... pixel, 142,202 ... display region, 1 DESCRIPTION OF SYMBOLS 3 ... Vertical direction wiring, 144 ... Horizontal direction wiring, 145 ... Horizontal signal circuit, 146 ... Vertical signal circuit, 203 ... Vertical direction wiring group, 204 ... Horizontal direction wiring group, 205 ... Power supply voltage output circuit, 206 ... Vertical scanning circuit 209, reset line 212, power control switch, 213, 223, driving TFT, 214, reset switch, 215
227 ... Storage capacity, 217,229 ... Power supply line, 218 ... Reset line, 219 ... Power supply control line, 222 ... AZB switch, 224 ... AZ switch, 225 ... Offset cancellation capacity, 226 ... Pixel switch, 230 ... Gate line, 231 , 232... AZB control line.

Claims (20)

A substrate,
An organic light emitting layer having a hole transport layer, a light emitting layer, and an electron transport layer;
A lower electrode disposed between the organic light emitting layer and the substrate;
An upper electrode disposed on the opposite side of the substrate with respect to the lower electrode;
In a display device having
The display device, wherein the hole transport layer includes a hole transport material and a metal oxide material. The display device according to claim 1,
A display device, wherein the metal oxide material has a work function of 5.5 eV or more. The display device according to claim 1 or 2,
The metal oxide material is molybdenum oxide, ruthenium oxide, aluminum oxide, bismuth oxide, gallium oxide, germanium oxide, magnesium oxide, antimony oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, zirconium oxide, iridium oxide, rhenium oxide. , A display device characterized in that it is made of any material of vanadium oxide and has a work function of 5.5 eV or more. The display device according to claim 1 or 2,
The display device, wherein the hole transport material of the hole transport layer is disposed closer to the light emitting layer than a position where the metal oxide material is disposed. The display device according to claim 1 or 2,
The display device, wherein the hole transport layer is a mixed layer composed of the hole transport material and the metal oxide material. The display device according to claim 1 or 2,
The display device, wherein the hole transport layer has a two-layer structure including a layer made of the hole transport material and a layer made of the metal oxide material. The display device according to claim 1 or 2,
The hole transport layer has a two-layer structure composed of a layer made of the hole transport material and a mixed layer composed of the hole transport material and the metal oxide material. apparatus. The display device according to claim 1 or 2,
The hole transport layer is composed of a layer composed of the hole transport material, a mixed layer composed of the hole transport material and the metal oxide material, and a layer composed of the layer composed of the metal oxide material. A display device having a structure. A substrate,
An organic light emitting layer having a hole transport layer, a light emitting layer, and an electron transport layer;
A lower electrode disposed between the organic light emitting layer and the substrate;
An upper electrode disposed on the opposite side of the substrate with respect to the lower electrode;
In a display device having
The display device, wherein the hole transport layer includes a hole transport material and a phthalocyanine material. The display device according to claim 9, wherein
A work function of the phthalocyanines is 5.2 eV or more. The display device according to claim 9, wherein
The display device characterized in that the material of the phthalocyanines is an oxide of copper phthalocyanine and having a work function of 5.2 eV or more. The display device according to claim 9, wherein
The display device, wherein the hole transport layer is a mixed layer composed of the hole transport material and the phthalocyanine material. The display device according to claim 9, wherein
The display device, wherein the hole transport layer has a two-layer structure including a layer made of a hole transport material and a layer made of a phthalocyanine material. The display device according to claim 13,
The display device characterized in that the layer made of the hole transport material of the hole transport layer is arranged closer to the light emitting layer than the arrangement position of the layer made of the phthalocyanine material. The display device according to claim 9, wherein
The hole transport layer has a two-layer structure composed of a layer made of the hole transport material and a mixed layer composed of the hole transport material and the phthalocyanine material. Display device. The display device according to claim 9, wherein
The hole transport layer is composed of a layer composed of the hole transport material, a mixed layer composed of the hole transport material and the phthalocyanine material, and a layer composed of the phthalocyanine material. A display device having a three-layer structure. The display device according to any one of claims 1 to 16,
An organic light emitting device having the organic light emitting layer, the lower electrode, and the upper electrode;
A signal line for inputting a display signal voltage to the organic light emitting element;
A display device comprising an active matrix display device having a plurality of pixels each composed of one or more thin film transistors for driving the organic light emitting element. The display device according to any one of claims 1 to 16,
A display device comprising a simple matrix type display device having a plurality of organic light emitting elements each having the organic light emitting layer, the lower electrode, and the upper electrode. A liquid crystal display element having a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and a pair of polarizing plates;
An illumination unit that irradiates light to the liquid crystal display element,
The illumination unit includes a substrate, an organic light emitting layer having a hole transport layer, a light emitting layer, and an electron transport layer, a lower electrode disposed between the organic light emitting layer and the substrate, and the lower electrode And a top electrode disposed on the opposite side of the substrate, wherein the hole transport layer is composed of a hole transport material and a metal oxide material. A liquid crystal display element having a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and a pair of polarizing plates;
An illumination unit that irradiates light to the liquid crystal display element,
The illumination unit includes a substrate, an organic light emitting layer having a hole transport layer, a light emitting layer, and an electron transport layer, a lower electrode disposed between the organic light emitting layer and the substrate, and the lower electrode with respect to the lower electrode. And a top electrode disposed on the opposite side of the substrate, wherein the hole transport layer is composed of a hole transport material and a phthalocyanine material.

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