JP2011029322A - Display device and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of suppressing leakage current, even when each organic EL element corresponding to a plurality of luminescent colors is constituted an independent material and film thickness, respectively, and to provide a method for manufacturing the display device. <P>SOLUTION: An organic layer 13 includes a hole-injecting layer 13a, a hole transport layer 13b, a light-emitting layer 13c and an electron transport layer 13d. The light-emitting layer 13c is formed along an end face of the hole transport layer 13b so that the end face of the hole transport layer 13b is covered with the light-emitting layer 13c and is not brought into contact with a second electrode 15. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a display device and a method for manufacturing the display device. More specifically, the present invention relates to a self-luminous display device using an organic EL element and a method for manufacturing the display device.

  In recent years, an organic EL display using an organic EL (Electro Luminescence) element has attracted attention as a display device that replaces a liquid crystal display. The organic EL display is a self-luminous display that emits light when an electric current is passed through the organic material. In addition to not requiring a backlight, it has excellent color reproducibility, high contrast, and responsiveness suitable for moving images. It has excellent features such as a wide viewing angle.

  In a full color display, one pixel is generally constituted by, for example, an R subpixel, a G subpixel, and a B subpixel. As a method for realizing full color in an organic EL display, a RGB color separation method in which organic EL elements that emit light of R (red), G (green), and B (blue) are independently formed is generally used.

  In the RGB separate-type organic EL display, as shown in FIG. 22, a first electrode 112, an organic layer 113, and a second electrode 115 are stacked on a substrate 111 to form an organic EL element 121. The organic EL element 121R emits red light to form an R subpixel. The organic EL element 121G emits green light and constitutes a G subpixel. The organic EL element 121B emits blue light and constitutes a B subpixel. In the organic EL display shown in FIG. 22, the film formation ranges of the organic EL elements 121R, 121G, and 121B do not overlap each other and are independent.

  In addition, in the organic EL display of the RGB coating method, as shown by the arrow a in the organic EL display shown in FIG. 23, a part of the film formation range of each organic layer 113 of the organic EL elements 121R, 121G, and 121B is Some of them overlap each other.

  22 and FIG. 23, the organic EL display of the RGB coating method has a structure in which the end surface of the organic layer 113 is exposed, and the end surface of the organic layer 113 and the second electrode 115 are in contact with each other.

  As shown in FIG. 24, when the end face of the organic layer 113 and the second electrode 115 come into contact with each other, the first electrode 111 and the second electrode 115 are interposed through the low resistance layer among the layers constituting the organic layer 113. Leakage current may occur between the two. That is, in the example of FIG. 24, the first electrode 111 and the second electrode are interposed through the hole transport layer 113b having a low resistance among the hole injection layer 113a, the hole transport layer 113b, the light emitting layer 113c, and the electron transport layer 113d. There is a possibility that a leakage current indicated by an arrow in the figure flows between the terminal 115 and the terminal 115.

  This leakage current changes in magnitude depending on the state of the end face of the organic layer 113 that is difficult to control, and therefore causes uneven light emission within the panel surface of the organic EL display.

  Therefore, techniques for preventing this leakage current are being studied. For example, Patent Document 1 describes a technique for preventing leakage current by forming an electron transport layer as a common layer for RGB and forming a film uniformly over the entire panel of an organic EL display.

Japanese Patent No. 3206646

  However, in the technique described in Patent Document 1, for example, in a full-color display, it is necessary to configure the electron transport layer of the organic EL element corresponding to each light emission of RGB with the same material and the same film thickness. On the other hand, in general, in an organic EL display, in order to maximize the characteristics of the organic EL element corresponding to each light emission of RGB, the organic layer is configured with a material and a film thickness different for each light emission of RGB.

  In the technique described in Patent Document 1, leakage current can be suppressed. However, since the electron transport layer needs to have a common configuration for each light emission of RGB, the material constituting the organic EL element corresponding to each light emission of RGB is used. Selection is limited, and it becomes difficult to construct an organic EL element having excellent characteristics.

  Therefore, an object of the present invention is to provide a display device and a display device manufacturing method capable of suppressing leakage current even when each organic EL element corresponding to a plurality of light emission colors is formed of independent materials and film thicknesses. It is in.

  In order to solve the above-described problem, the first invention includes a first electrode, a second electrode, and an organic layer provided between the first electrode and the second electrode and made of an organic material. The organic layer is composed of a plurality of layers including a light emitting layer, and an end face of the first layer composed of at least one of the plurality of layers is at least one of the layers located above the first layer. The display device is covered by a second layer composed of layers.

  According to a second aspect of the invention, there is provided an organic layer composed of a plurality of layers composed of an organic material, including a light emitting layer, which is provided between the first electrode, the second electrode, and the first electrode and the second electrode. The organic layer forming step includes a first step of forming a first layer composed of at least one of a plurality of layers, and a position above the first layer. And a second step of forming a second layer of at least one of the layers to be formed along an end surface of the first layer.

  In the first invention, the end face of the first layer that causes the leakage current is covered with the second layer. Thereby, contact between the end surface of the first layer that causes leakage current and the second electrode can be avoided, and thus leakage current can be suppressed.

  In the second invention, the second layer is formed along the end face of the first layer that causes the leakage current. Thereby, contact between the end surface of the first layer that causes leakage current and the second electrode can be avoided, and thus leakage current can be suppressed.

  According to the present invention, leakage current can be suppressed even when each organic EL element corresponding to a plurality of emission colors is formed of independent materials and film thicknesses.

It is sectional drawing which shows the structure of the display apparatus by 1st Embodiment of this invention. It is principal part sectional drawing which shows the structure of the organic layer of the display apparatus by 1st Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the display apparatus by the 2nd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the display apparatus by the 2nd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the organic layer in 2nd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the organic layer in 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the display apparatus by the 3rd Embodiment of this invention. It is principal part sectional drawing which shows the structure of the organic layer of the display apparatus by 3rd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the organic layer in 4th Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the organic layer in 4th Embodiment of this invention. It is a top view for demonstrating the film-forming area | region of the manufacturing method of the display apparatus by 6th Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the display apparatus by 6th Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the organic layer in 7th Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of the organic layer in 7th Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing process of a display apparatus. It is a top view showing schematic structure of the module containing a display apparatus. It is a perspective view showing the external appearance of the application example 1 of a display apparatus. It is a perspective view showing the external appearance of the application example 2 of a display apparatus. It is a perspective view showing the external appearance of the application example 3 of a display apparatus. It is a perspective view showing the external appearance of the application example 4 of a display apparatus. It is a basic diagram showing the external appearance of the application example 5 of a display apparatus. It is sectional drawing which shows the structure of the conventional display apparatus. It is sectional drawing which shows the structure of the conventional display apparatus. It is sectional drawing which shows the structure of the organic layer of the conventional display apparatus.

Embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are specific examples of the present invention, and various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless stated to the effect, the present invention is not limited to the embodiment. The description will be given in the following order, and the same or corresponding parts are denoted by the same reference symbols in all drawings of the embodiments.
1. First embodiment (first example of display device)
2. Second embodiment (first example of manufacturing method of display device)
3. Third embodiment (second example of display device)
4). Fourth Embodiment (Second Example of Manufacturing Method of Display Device)
5). Fifth embodiment (third example of display device)
6). Sixth Embodiment (Third Example of Display Device Manufacturing Method)
7). Seventh Embodiment (Fourth Example of Manufacturing Method of Display Device)
8). 8. Application example of display device Other embodiment (modification)

1. First Embodiment (Configuration of Display Device)
A display device according to a first embodiment of the present invention will be described. FIG. 1 is a sectional view showing a configuration example of a display device according to the first embodiment of the present invention. This display device is a top emission type (so-called top emission type) display device configured to extract emitted light from the upper surface side of the substrate 11. This display device includes an organic EL element 21 having a structure in which an organic layer 13 is sandwiched between a first electrode 12 and a second electrode 15 provided on a substrate 11.

[substrate]
The substrate 11 is formed of a transparent substrate that does not absorb in the visible region. For example, a silicon substrate, a glass substrate, a plastic substrate, or the like can be used.

[First electrode]
The first electrode 12 (anode) is an electrode that injects holes into the light emitting layer 13c, and is patterned in a matrix so that a voltage-current can be applied at a predetermined position on the substrate 11. As a material of the first electrode 12, a silver alloy, an aluminum-neodymium alloy, or the like can be used.

[Insulation layer]
The insulating layer 18 is provided to ensure insulation between the first electrode 12 and the second electrode 15.
As a material of the insulating layer 18, for example, a photosensitive resin such as polyimide is used. The insulating layer 18 is formed to have a portion where the first electrode 12 is exposed by applying a photosensitive resin on the first electrode 12 and patterning it by photolithography. The organic layer 13 including the light emitting layer 13 c and the second electrode 15 are stacked on the exposed portion of the first electrode 12. Above the exposed portion of the first electrode 12, each organic layer 13 corresponding to each emission of R, G, and B is formed to be a light emitting region that emits light.

[Organic layer]
The organic layer 13 includes a hole injection layer 13a, a hole transport layer 13b, a light emitting layer 13c, and an electron transport layer 13d. The hole injection layer 13a, the hole transport layer 13b, the light emitting layer 13c, and the electron transport layer 13d are stacked in this order from the substrate 11 side.

  The hole injection layer 13 a is a layer provided for smoothly receiving holes from the first electrode 12. The hole transport layer 13b is a layer provided to smoothly move holes to the light emitting layer 13c. The electron transport layer 13d is a layer that receives electrons from the second electrode 15 and transports them to the light emitting layer 13c.

  The light emitting layer 13c is a layer that emits light by recombination of holes and electrons. The organic EL element 21R emits R. The organic EL element 21G emits G. The organic EL element 21B emits B. In the organic EL element 21, when a necessary voltage-current is applied between the first electrode 12 and the second electrode 15, holes are injected from the first electrode 12 and electrons are injected from the second electrode 15 into the light emitting layer 13c. The light emitting layer 13c emits light by recombination of holes and electrons.

  For the hole injection layer 13a, the hole transport layer 13b, the light emitting layer 13c, and the electron transport layer 13d constituting the organic layer 21, materials suitable for the respective functions can be used. The material and thickness of each layer constituting the organic layer 21 are appropriately selected according to each emission of R, G, and B. In order to maximize the characteristics such as light emission efficiency, drive voltage, and light emission lifetime, each layer constituting the organic layer 21 is made of a suitable material and thickness according to each light emission of R, G, and B. The

  As a material constituting the hole injection layer 13a, a hexaazatriphenylene derivative, an aromatic amine derivative, or the like can be used. The thickness of the hole injection layer 13a is selected within a range of 3 nm to 100 nm, for example.

  As a material constituting the hole transport layer 13b, N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (TPD) is used. 4,4 ′, 4 ″ -tris [3-methylphenyl (phenyl) amino] triphenylamine (m-MTDATA), 4,4 ′, 4 ″ -tris [1-naphthyl (phenyl) amino] tri Phenylamine (1-TNATA), 4,4 ′, 4 ″ -tris [2-naphthyl (phenyl) amino] trisphenylamine (2-TNATA), 4,4 ′, 4 ″ -tris [biphenyl-4 -Yl- (3-methylphenyl) amino] triphenylamine (p-PMTDATA), 4,4 ′, 4 ″ -tris [9,9-dimethyl-2-fluorenyl (phenyl) amino] triphenylamine (TFATA) ), 4, 4 ′, 4 ″ -tri (N-carbazolyl) triphenylamine (TCTA), 1,3,5-tris [N- (4-diphenylaminophenyl) phenylamino] benzene (p-DPA-TDAB), 1 , 3,5-tris {4- [methylphenyl (phenyl) amino] phenyl} benzene (MTDAPB), N, N ″ -di (biphenyl-4-yl) -N, N′-diphenyl- [1,1 '-Biphenyl] -4,4'-diamine (p-BPD), N, N, N', N'-tetrakis (9,9-dimethyl-2-fluorenyl)-[1,1'-biphenyl] -4 , 4′-diamine (FFD) and the like can be used. The thickness of the hole transport layer 13b is selected, for example, within a range of 5 nm to 300 nm.

  As a material constituting the light emitting layer 13c, for example, a low molecular fluorescent dye, a polymer, a metal complex, or the like can be used. The material constituting the light emitting layer 13c is appropriately selected according to the emission color. The thickness of the light emitting layer 13c is selected within a range of 5 nm to 100 nm, for example.

  The light emitting layer 13c may be configured, for example, by adding a small amount of a dopant material to the host material. As the host material, for example, an aromatic hydrocarbon compound having a phenylene nucleus, a naphthalene nucleus, an anthracene nucleus, a pyrene nucleus, a naphthacene nucleus, a chrysene nucleus, or a perylene nucleus can be used. Specific examples of the aromatic hydrocarbon compound include 9,10-di (2-naphthyl) anthracene (ADN) and rubrene.

  As a material which becomes a dopant, organic compounds such as naphthalene derivatives, amine compounds, pyrene derivatives, anthracene derivatives, naphthacene derivatives, perylene derivatives, coumarin derivatives, and pyran dyes can be used.

  As a material constituting the electron transport layer 13d, for example, quinoline, perylene, bisstyryl, pyrazine, triazole, oxazole, oxadiazole, fluorenone, or derivatives thereof can be used. Specifically, for example, Alq3 (8-hydroxynoline aluminum) can be used. The thickness of the electron transport layer 13d is selected, for example, within a range of 5 nm to 300 nm.

[Second electrode]
The second electrode (cathode) 15 is an electrode for injecting electrons into the light emitting layer 13c. As the material of the second electrode 15, for example, magnesium (Mg), calcium (Ca), sodium (Na), MgAg alloy, or the like can be used. The second electrode 15 may be composed of two layers, that is, a layer made of the above material and a layer made of an alkali metal halide such as LiF.

  One pixel of the display device is composed of three sub-pixels of an R sub-pixel, a G sub-pixel, and a B sub-pixel, and the organic EL element 21 constitutes one sub-pixel. The organic EL element 21R constitutes an R subpixel, the organic EL element 21G constitutes a G subpixel, and the organic EL element 21B constitutes a B subpixel. In addition, in this specification, when not distinguishing the organic EL element 21R, the organic EL element 21G, and the organic EL element 21B, it describes with the organic EL element 21. FIG.

  The organic EL element 21R, the organic EL element 21G, and the organic EL element 21B are arranged in a matrix. Moreover, the organic EL element 21R, the organic EL element 21G, and the organic EL element 21B are juxtaposed.

  Each organic EL element 21 is connected to a TFT (Thin Film Transistor) (not shown) formed on the substrate 11, and light emission is controlled independently. This TFT is formed, for example, by repeating film formation by plasma CVD and pattern formation by photolithography.

  As shown in FIG. 2, the organic EL element 21 has a structure in which the end face of the hole transport layer 13b is covered with a light emitting layer 13c formed along the end face. This prevents the end face of the hole transport layer 13b from coming into contact with the second electrode 15.

  That is, the light emitting layer 13c has a higher resistance than the hole transport layer 13b, and the light emitting layer 13c covers the end face of the hole transport layer 13b. Thereby, the end face of the hole transport layer 13b is prevented from being exposed from the light emitting layer 13c. In this structure, since the light emitting layer 13c is interposed between the end face of the hole transport layer 13b and the second electrode 15, the end face of the hole transport layer 13b and the second electrode 15 do not contact each other.

  With this structure, the current flow between the hole transport layer 13b and the second electrode 15 can be blocked by the light emitting layer 13c. That is, the current flow from the first electrode 12 as indicated by the arrow in the figure can be blocked by the light emitting layer 13c. Thereby, the current leaking to the second electrode 15 through the end face of the hole transport layer 13b can be suppressed.

  Thus, in the first embodiment, the current that leaks to the second electrode 15 through the end face of the hole transport layer 13b is targeted for suppression. That is, since the resistance of the hole transport layer 13b among the layers constituting the organic layer 13 is low, when the end face of the hole transport layer 13b and the second electrode 15 come into contact, a leakage current is generated from the end face of the hole transport layer 13b. It will occur. Therefore, in the first embodiment, the light emitting layer 13c having a higher resistance than the hole transport layer 13b is interposed between the end surface of the hole transport layer 13b that causes the leak current and the second electrode 15. This suppresses a current leaking to the second electrode 15 through the end face of the hole transport layer 13b.

[Protective film]
The protective film 17 is a passivation film made of a transparent dielectric. As a material of the protective film 17, silicon oxide (SiO ₂ ), silicon nitride (SiN), or the like can be used. The thickness of the passivation film is, for example, 500 nm to 10,000 nm.

[Encapsulation substrate]
The sealing substrate 19 is adhered to an adhesive layer (not shown) formed on the protective film 17 and seals the organic EL element 21. The sealing substrate 19 is made of a transparent material such as glass.

<Effect>
In the first embodiment of the present invention, the end face of the hole transport layer 13b that causes a leak current is covered with the light emitting layer 13c formed along the end face of the hole transport layer 13b. Thereby, since contact with the hole transport layer 13b and the second electrode 15 can be avoided, leakage current can be suppressed.

2. Second embodiment (display device manufacturing method)
A method for manufacturing the above-described display device will be described with reference to FIGS. In the following description, first, the overall flow of the display device manufacturing method will be briefly described with reference to FIGS. 3 to 4, and then the main part of the present invention will be described with reference to FIGS. 5 to 6. The step of forming the organic layer 13 will be described in detail.

[Formation of first electrode and insulating layer]
First, as shown in FIG. 3A, the first electrode 12 is formed on the substrate 11 on which the TFT (not shown) is formed, and then the insulating layer 18 is formed. The first electrode 12 is patterned in a matrix by photolithography and etching after the first electrode 12 is formed on the entire surface of the substrate by vacuum deposition.

  The insulating layer 18 is patterned so as to cover the periphery of the patterned first electrode 12. Thereby, a portion where the first electrode 12 is exposed is formed. In the portion where the first electrode 12 is exposed, the organic layer 13 and the like are formed to form a light emitting region. For example, a photosensitive resin is applied by spin coating, and then the insulating layer 18 is patterned by photolithography.

[Formation of organic layer]
Next, as shown in FIGS. 3B to 3C and 4D, an organic layer 13 corresponding to the R light emitting region, an organic layer 13 corresponding to the G light emitting region, and the organic layer 13 on the first electrode 12 by vacuum deposition. The organic layer 13 corresponding to the light emitting region of B is formed in this order.

  Hereinafter, the organic layer 13 corresponding to the R emission region is appropriately referred to as an organic layer 13 (R). The organic layer 13 corresponding to the G light emitting region is appropriately referred to as an organic layer 13 (G). The organic layer 13 corresponding to the light emitting region of B is appropriately referred to as an organic layer 13 (B). Moreover, the order of formation of the organic layer 13 (R), the organic layer 13 (G), and the organic layer (B) is not limited to this order. For example, the organic layer (B), the organic layer 13 (G), and the organic layer 13 (R) may be formed in this order. The formation of the organic layer 13 will be described in detail later with reference to FIGS.

[Formation of second electrode]
Next, as shown in FIG. 4E, the second electrode 15 is formed by vacuum deposition. The second electrode 15 is formed by vacuum-depositing a material to be the second electrode 15 on the entire surface of the organic layer 13 and part of the insulating layer 18.

[Formation of protective film, etc.]
Thereafter, as shown in FIG. 4F, a protective film 17 is vacuum-deposited on the second electrode 15, and further, an adhesive layer (not shown) is formed on the protective film 17 by spin coating an ultraviolet curable resin. The sealing substrate 19 is bonded to the protective film 17 via an adhesive layer. Thus, a display device can be obtained.

[Formation of organic layer]
The formation of the organic layer 13 will be described in more detail with reference to FIGS. The organic layer 13 (R) corresponding to the R light emitting region, the organic layer 13 (G) corresponding to the G light emitting region, and the organic layer 13 (B) corresponding to the B light emitting region are formed by the steps described below. It forms sequentially as mentioned above.

[Formation of hole injection layer]
First, as shown in FIG. 5B, a hole injection layer 13a is formed on the first electrode 12 and the insulating layer 18 formed on the substrate 11 shown in FIG. 5A. The hole injection layer 13a is formed by a vacuum evaporation method. The hole injection layer 13a is formed by vacuum-depositing an organic material to be the hole injection layer 13a in a state where the mask 31 is disposed between the evaporation source (not shown) and the first electrode 12.

  This organic material passes through the opening of the mask 31 and is deposited on the exposed portion of the first electrode 12 and a part of the insulating layer 18 provided on the peripheral portion of the first electrode 12. As a result, the hole injection layer 13a is patterned in the film formation region corresponding to the opening of the mask 31.

  Each of the openings of the mask 31 is set to a rectangular shape, for example. The opening size of the mask 31 is set larger than that of the mask 32 having a rectangular opening used in a process described later. For example, each of the four sides of the opening of the mask 31 is set to be larger than each of the four sides of the opening of the mask 32. For example, the difference between the four sides is set to be 0.5 μm or more.

[Formation of hole transport layer]
Next, as shown in FIG. 5C, the hole transport layer 13b is formed on the hole injection layer 13a. The hole transport layer 13b is formed by a vacuum evaporation method. The hole transport layer 13b is vacuum-deposited with an organic material serving as the material of the light emitting layer 13c in a state where the mask 32 is disposed between a deposition source (not shown) and the hole injection layer 13a. This organic material passes through the opening of the mask 32 and is deposited on the hole injection layer 13a. Thereby, the hole transport layer 13b is patterned in the film formation region corresponding to the opening of the mask 32.

[Formation of light emitting layer]
Next, as illustrated in FIG. 6D, the light emitting layer 13c is formed on the hole transport layer 13b. The light emitting layer 13c is formed by a vacuum evaporation method. The light emitting layer 13c is vacuum-deposited with an organic material to be the light emitting layer 13c in a state where the mask 31 is disposed between the vapor deposition source (not shown) and the hole transport layer 13b. This organic material passes through the opening of the mask 31 and is deposited on the hole transport layer 13b. The organic material is deposited on the hole injection layer 13a along the end face of the hole transport layer 13b. As a result, the light emitting layer 13 c is patterned in the film formation region corresponding to the opening of the mask 31.

  The mask 31 used in the step shown in FIG. 6D has a larger opening size than the mask 32 described above. Therefore, the film formation region of the light emitting layer 13 c corresponding to the opening of the mask 31 is larger than the film formation region of the hole transport layer 13 b corresponding to the mask 32. Thereby, in a region where the film formation region of the light emitting layer 13c and the film formation region of the hole transport layer 13b do not overlap, the organic layer that becomes the light emitting layer 13c on the hole injection layer 13a along the end face of the hole transport layer 13b. The material is deposited to form a structure in which the end surface of the hole transport layer 13b is covered with the light emitting layer 13c.

[Formation of electron transport layer]
Next, as shown in FIG. 6E, the electron transport layer 13d is formed on the light emitting layer 13c. The electron transport layer 13d is formed by a vacuum evaporation method. The electron transport layer 13d is vacuum-deposited with an organic material to be the electron transport layer 13d in a state where the mask 31 is disposed between the vapor deposition source (not shown) and the light emitting layer. This organic material passes through the opening of the mask 31 and is deposited on the light emitting layer 13c. Thus, the electron transport layer 13d is patterned in the film formation region corresponding to the opening of the mask 31.

  In the formation process of the organic layer 13 described above, the hole injection layer 13a, the hole transport layer 13b, the light emitting layer 13c, and the electron transport layer 13d are formed in this order. During film formation, the film formation region of the light emitting layer 13c formed above the layer (here, the hole transport layer 13b) that causes a low-resistance leakage current among the above layers causes a leakage current. The layer is made wider than the film formation region. Note that the resistance of the light emitting layer 13c is set higher than that of the layer causing the leakage current.

<Effect>
In the second embodiment of the present invention, in the formation of the organic layer 13, the film formation region of the light emitting layer 13 c above the hole transport layer 13 b having a low resistance that causes the leakage current causes the leakage current. The layer is made wider than the film formation region. Thereby, the light emitting layer 13c is formed along the end face of the hole transport layer 13b, and the leak current caused by the contact between the end face of the layer causing the leak current and the second electrode 15 can be suppressed.

3. Third embodiment
(Configuration of display device)
A display device according to a third embodiment of the invention will be described. FIG. 7 is a sectional view showing the structure of a display device according to the third embodiment of the present invention. The display device according to the third embodiment is the same as the configuration of the display device according to the first embodiment except for the configuration of the organic layer 13. Therefore, below, it demonstrates focusing on the structure of the organic layer 13, and abbreviate | omits other description.

  As shown in FIG. 7, the organic layer 13 includes a hole injection layer 13a, a hole transport layer 13b, a light emitting layer 13c, and an electron transport layer 13d, as in the first embodiment. The hole injection layer 13a, the hole transport layer 13b, the light emitting layer 13c, and the electron transport layer 13d are stacked in this order from the substrate 11 side.

  As shown in FIG. 8, the organic EL element 21 has a structure in which the end surfaces of the hole injection layer 13a and the hole transport layer 13b are covered with a light emitting layer 13c formed along these end surfaces. This prevents the end face of the hole injection layer 13 a and the end face of the hole transport layer 13 b from contacting the second electrode 15.

  That is, the light emitting layer 13c has a higher resistance than the hole injection layer 13a and the hole transport layer 13b, and the light emitting layer 13c covers the end surfaces of the hole injection layer 13a and the hole transport layer 13b. Thereby, the end surfaces of the hole injection layer 13a and the hole transport layer 13b are prevented from being exposed from the light emitting layer 13c. In this structure, since the light emitting layer 13c is interposed between the end surfaces of the hole injection layer 13a and the hole transport layer 13b and the second electrode 15, the end surfaces of the hole injection layer 13a and the hole transport layer 13b There is no contact with the second electrode 15.

  With this structure, the current flow between the hole injection layer 13a and the hole transport layer 13b and the second electrode 15 can be blocked by the light emitting layer 13c. That is, the current flow from the first electrode 12 as shown by the arrow in the figure can be blocked by the light emitting layer 13c. Thereby, the current leaking to the second electrode 15 through the end surfaces of the hole injection layer 13a and the hole transport layer 13b can be suppressed.

  Thus, in the third embodiment, the current leaking to the second electrode 15 through the end faces of the hole injection layer 13a and the hole transport layer 13b is targeted for suppression. That is, since the resistance of the hole injection layer 13a and the hole transport layer 13b among the layers constituting the organic layer 13 is low, at least one of the end surfaces of the hole injection layer 13a and the hole transport layer 13b and the second electrode 15 When contacted, a leak current is generated from these end faces. Therefore, in the third embodiment, the light emitting layer 13c having a higher resistance than these layers is provided between the end surfaces of the hole injection layer 13a and the hole transport layer 13b, which cause a leak current, and the second electrode 15. Intervene. Thereby, the current leaking to the second electrode 15 through the end faces of the hole injection layer 13a and the hole transport layer 13b is suppressed.

<Effect>
In the third embodiment of the present invention, the end surfaces of the hole injection layer 13a and the hole transport layer 13b that cause the leakage current are covered with the light emitting layer 13c formed along these end surfaces. Thereby, the contact between the end face of the hole injection layer 13a and the end face of the hole transport layer 13b and the second electrode 15 can be avoided, so that the leakage current can be suppressed.

4). Fourth embodiment (display device manufacturing method)
A method for manufacturing the above-described display device will be described. Since the manufacturing method of the display device is the same as that of the second embodiment except for the formation of the organic layer 13, the following description explains the formation of the organic layer 13 in detail, and the other descriptions are omitted. To do.

[Formation of organic layer]
The formation of the organic layer 13 will be described with reference to FIG. The organic layer 13 (R) corresponding to the R light emitting region, the organic layer 13 (G) corresponding to the G light emitting region, and the organic layer 13 (B) corresponding to the B light emitting region are formed by the steps described below. It forms sequentially as mentioned above.

[Formation of hole injection layer]
First, as shown in FIG. 9B, a hole injection layer 13a is formed on the first electrode 12 and the insulating layer 18 formed on the substrate 11 shown in FIG. 9A. The hole injection layer 13a is formed by a vacuum evaporation method. The hole injection layer 13a is formed by vacuum-depositing an organic material to be the hole injection layer 13a in a state where the mask 32 is disposed between the evaporation source (not shown) and the first electrode.

  The organic material passes through the opening of the mask 32 and is deposited on the exposed portion of the first electrode 12 and a part of the insulating layer 18 provided on the peripheral portion of the first electrode 12. As a result, the hole injection layer 13a is patterned in the film formation region corresponding to the opening of the mask 32.

  Note that the opening size of the mask 32 is set smaller than that of the mask 31 used in a process described later. For example, the opening of the mask 32 and the mask 31 used in a process described later is, for example, rectangular. For example, the length of each of the four sides of the opening of the mask 32 is set smaller than the length of each of the four sides of the opening of the mask 31. For example, the difference between the four sides is set to be 0.5 μm or more.

[Formation of hole transport layer]
Next, as shown in FIG. 9C, the hole transport layer 13b is formed on the hole injection layer 13a. The hole transport layer 13b is formed by a vacuum evaporation method. The hole transport layer 13b is vacuum-deposited with an organic material to be the hole transport layer 13b in a state where the mask 32 is disposed between the deposition source (not shown) and the hole injection layer 13a. This organic material passes through the opening of the mask 32 and is deposited on the hole injection layer 13a. Thereby, the hole transport layer 13b is patterned in the film formation region corresponding to the opening of the mask 32.

[Formation of light emitting layer]
Next, as illustrated in FIG. 10D, the light emitting layer 13c is formed on the hole transport layer 13b. The light emitting layer 13c is formed by a vacuum evaporation method. The light emitting layer 13c is vacuum-deposited with an organic material serving as the material of the light emitting layer 13c in a state where the mask 31 is disposed between the vapor deposition source (not shown) and the hole transport layer 13b. This organic material passes through the opening of the mask 31 and is deposited on the upper surface of the hole transport layer 13b. In addition, the organic material is deposited on the insulating layer 18 along the end face of the hole injection layer 13a and the end face of the hole transport layer 13b. As a result, the light emitting layer 13 c is patterned in the film formation region corresponding to the opening of the mask 31.

  The mask 31 used in the step shown in FIG. 10D has a larger opening size than the mask 32 described above. Therefore, the film formation region of the light emitting layer 13 c corresponding to the opening of the mask 31 is larger than the film formation region of the hole injection layer 13 a and the hole transport layer 13 b corresponding to the mask 32. Thereby, in the region where the film formation region of the light emitting layer 13c and the film formation region of the hole injection layer 13a and the hole transport layer 13b do not overlap, the organic material that becomes the light emitting layer 13c is deposited as follows. . That is, an organic material that becomes the light emitting layer 13c is deposited on a part of the insulating layer 18 along the end face of the hole injection layer 13a and the end face of the hole transport layer 13b, and the end face of the hole injection layer 13a and the hole A structure in which the end face of the transport layer 13b is covered with the light emitting layer 13c is formed.

[Formation of electron transport layer]
Next, as shown in FIG. 10E, the electron transport layer 13d is formed on the light emitting layer 13c. The electron transport layer 13d is formed by a vacuum evaporation method. The electron transport layer 13d is vacuum-deposited with an organic material to be the electron transport layer 13d in a state where the mask 31 is disposed between the vapor deposition source (not shown) and the light emitting layer 13c. This organic material passes through the opening of the mask 31 and is deposited on the light emitting layer 13c. Thus, the electron transport layer 13d is patterned in the film formation region corresponding to the opening of the mask 31.

  In the formation process of the organic layer 13 described above, the hole injection layer 13a, the hole transport layer 13b, the light emitting layer 13c, and the electron transport layer 13d are formed in this order. In the film formation, the film formation region of the light emitting layer 13c above the layer that causes the leak current (here, the hole injection layer 13a and the hole transport layer 13b) is formed into a layer that causes the leak current. I try to make it wider than the area. The light emitting layer 13c has a higher resistance than the hole injection layer 13a and the hole transport layer 13b.

<Effect>
In the fourth embodiment of the present invention, in the formation of the organic layer, the film formation region of the light emitting layer 13c above the hole transporting layer 13a and the hole injecting layer 13b having a low resistance that causes a leakage current is corrected. It is made wider than the film-forming region of the hole transport layer 13a and the hole injection layer 13b. Thus, a structure is formed in which the end face of the hole injection layer 13a and the end face of the hole transport layer 13b are covered with the light emitting layer 13c formed along the end face. Therefore, the leakage current generated by the contact between the end face of the layer causing the leakage current and the second electrode 15 can be suppressed.

5). Fifth embodiment (configuration of display device)
The structure of the display device according to the fifth embodiment of the invention will be described. In the configuration of the display device according to the fifth embodiment of the present invention, in the display device shown in FIG. 1, the material and thickness of the hole transport layer 13b are common to the organic EL elements 21R, 21G, and 21B. . About others, it is the same as that of 1st Embodiment.

<Effect>
The fifth embodiment of the present invention has the same effect as that of the first embodiment of the present invention.

6). Sixth embodiment (display device manufacturing method)
A method for manufacturing the above-described display device will be described. In this display device manufacturing method, the hole transport layer 13b of the organic layer 13 (R), the organic layer 13 (G), and the organic layer 13 (B) having the same material and thickness is collectively formed. The hole transport layer 13b is formed by collectively forming the common constituent materials with the same film thickness. Thereafter, layers other than the hole transport layer 13b are sequentially formed for each organic layer 13 by depositing the constituent materials.

  The film formation region at this time will be described with reference to FIG. As shown in FIG. 11, a rectangular film formation region surrounded by a line Q1 (hereinafter referred to as a narrow film formation region Q1) and a rectangular film formation region surrounded by a line Q2 (hereinafter referred to as a wide film formation region Q2). 1) is set as a film formation region of a material to be each layer of the organic layer 13.

  The narrow film formation region Q1 is set as a film formation region of a material constituting the hole transport layer 13b having a low resistance that causes leakage. The wide film formation region Q2 is set as a film formation region of the material constituting the other organic layer 13. A display device manufacturing method according to the sixth embodiment of the present invention will be described below with reference to FIGS.

[Formation of first electrode and insulating layer 18]
First, as shown in FIG. 12A, the first electrode 12 is formed on the substrate 11 on which the TFT (not shown) is formed, and then the insulating layer 18 is formed. The first electrode 12 is formed in a matrix by photolithography and etching after forming a material to be the first electrode 12 on the entire surface of the substrate by vacuum deposition.

  The insulating layer 18 is patterned so as to cover the periphery of the patterned first electrode 12. Thereby, a portion where the first electrode 12 is exposed is formed. The insulating layer 18 is formed with a pattern by photolithography after applying a photosensitive resin, for example, by spin coating.

[Formation of hole injection layer]
Thereafter, the hole injection layer 13a of each organic layer 13 corresponding to each of the R, G, and B light emitting regions is sequentially patterned by a vacuum deposition method. The film formation region at this time is a wide film formation region Q2 shown in FIG. Although not shown, a mask having an opening size corresponding to a wide film formation region Q2 is used.

[Formation of hole transport layer]
Next, as shown in FIG. 12B, the hole transport layer 13b corresponding to each of the R, G, and B light emitting regions is simultaneously formed with the same film thickness by a vacuum deposition method. The film formation region is a narrow film formation region Q1 shown in FIG. At this time, a mask 53 having an opening size corresponding to the narrow film formation region Q1 is used.

[Formation of light emitting layer and electron transport layer]
Next, as shown in FIG. 12C, the light emitting layer 13c and the electron transport layer 13d corresponding to the R light emitting region are sequentially patterned. The film formation region at this time is a wide film formation region Q2. The opening size of the mask 55 used at this time corresponds to a wide film formation region Q2.

  Next, as shown in FIG. 13D, the light emitting layer 13c and the electron transport layer 13d corresponding to the G light emitting region are sequentially patterned. The film formation region at this time is a wide film formation region Q2 shown in FIG. The opening of the mask 55 used at this time corresponds to a wide film formation region Q2.

  Next, as shown in FIG. 13E, the light emitting layer 13c and the electron transporting layer 13d corresponding to the B light emitting region are sequentially patterned. The film formation region at this time is a wide film formation region Q2 shown in FIG. The opening size of the mask 55 used at this time corresponds to a wide film formation region Q2.

[Formation of second electrode, etc.]
Next, as shown in FIG. 13F, the second electrode 15 and the protective film 17 are formed. The second electrode 15 is formed by a vacuum evaporation method. The second electrode 15 is vacuum deposited on the entire surface of the electron transport layer 13d and a part of the insulating layer 18. Thereafter, the protective film 17 is vacuum-deposited on the second electrode 15, and further, an ultraviolet curable resin is spin-coated on the protective film 17 to form an adhesive layer (not shown). It adheres to 17 through an adhesive layer. Thus, a display device can be obtained.

<Effect>
The display device manufacturing method according to the sixth embodiment of the present invention has the same effects as those of the second embodiment.

7). Seventh embodiment (display device manufacturing method)
A display device manufacturing method according to the seventh embodiment of the present invention will be described. The formation of the organic layer 13 which is the main part of the present invention is different from that of the second embodiment, and the others are the same as those of the second embodiment. Therefore, in the following, the formation of the organic layer 13 will be described, and other description will be omitted.

[Formation of organic layer]
The formation of the organic layer 13 will be described with reference to FIGS. 14 and 15. The organic layer 13 (R) corresponding to the R emission region, the organic layer 13 (G) corresponding to the G emission region, and the organic layer 13 (B) corresponding to the B emission region are formed by the steps described below. To do.

[Formation of Hole Injection Layer 13a]
First, the hole injection layer 13a is formed on the first electrode 12 and the insulating layer 18 formed on the substrate 11 shown in FIG. 14A. The hole injection layer 13a is formed by a transfer method. That is, first, as shown in FIG. 14B, the transfer substrate 30 is placed in a state in which the first electrode 12 and the transfer layer 33a made of an organic material to be the hole injection layer 13a are arranged to face each other.

The transfer substrate 30 has an oxidation protection layer 35 made of SiN _x , SiO ₂ or the like, a photothermal conversion layer 34 made of Cr, Mo, or the like, and a transfer layer 33 made of an organic material to be thermally transferred. Are stacked in this order. The transfer layer 33 is patterned on the photothermal conversion layer 34 in a predetermined region P1 (region surrounded by a dotted line in the figure) corresponding to a region where the hole injection layer 13a is formed. The transfer layer 33 is thermally transferred by a process described later.

  Next, the laser beam L is irradiated from the substrate 31 side. The photothermal conversion layer 34 absorbs the irradiation energy of the laser light L, and the heat is used to thermally transfer the transfer layer 33 made of a material to be the hole injection layer 13 a onto the first electrode 12. As the laser light, for example, laser light having a wavelength of about 800 nm is used. As a result, the hole injection layer 13a is patterned in a region corresponding to the predetermined region P1 on the exposed portion of the first electrode 12 and the insulating layer 18.

  Note that the predetermined region P1 in which the transfer layer 33 made of a material to be the hole injection layer 13a is formed is, for example, a rectangular region. The predetermined region P1 is set to be wider than the predetermined region P2 where the transfer layer 33 made of a material to be the hole transport layer 13b is formed in a process described later. For example, each of the four sides of the rectangular predetermined region P1 is set to be larger than each of the four sides of the rectangular predetermined region P2. For example, it is preferable that the difference between the four sides is set to be 0.5 μm or more, for example.

[Formation of hole transport layer 13b]
Next, the hole transport layer 13b is formed on the hole injection layer 13a. The hole transport layer 13b is formed by a transfer method. That is, as shown in FIG. 14C, first, the transfer substrate 30 is placed in a state where the hole injection layer 13a and the transfer layer 33 made of an organic material to be the hole transport layer 13b are arranged to face each other. . The transfer layer 33 is patterned on the photothermal conversion layer 34 in a predetermined region P2 (region surrounded by a dotted line in the figure) corresponding to a region where the hole transport layer 13b is formed.

  Next, the laser beam L is irradiated from the substrate 31 side. The photothermal conversion layer 34 absorbs the irradiation energy of the laser light L, and the heat is used to thermally transfer the transfer layer 33 made of a material to be the hole transport layer 13 b onto the hole injection layer 13. Thereby, the hole transport layer 13b is patterned in a region corresponding to the predetermined region P2.

[Formation of light emitting layer]
Next, the light emitting layer 13c is formed on the hole transport layer 13b. The light emitting layer 13c is formed by a transfer method. That is, as shown in FIG. 15D, first, the transfer substrate 30 is placed in a state in which the hole transport layer 13b and the transfer layer 33 made of an organic material that becomes the light emitting layer 13c are arranged to face each other. The transfer layer 33 is patterned on a predetermined region P1 corresponding to the region where the light emitting layer 13c is formed on the photothermal conversion layer 34.

  Next, the laser beam L is irradiated from the substrate 31 side. The photothermal conversion layer absorbs the irradiation energy of the laser light L, and using the heat, the transfer layer 33 made of a material that becomes the light emitting layer 13c is thermally transferred onto the hole transport layer 13b. Thereby, the light emitting layer 13c is patterned in a region corresponding to the predetermined region P1.

  In the step shown in FIG. 15D, the predetermined area P1 is wider than the predetermined area P2. Therefore, the formation region of the light emitting layer 13c is wider than the formation region of the hole transport layer 13b. As a result, in the predetermined region P1, in the region that does not overlap with the predetermined region P2, the organic material that becomes the light emitting layer 13c is formed in a part of the insulating layer 18 along the end face of the hole transport layer 13b. A structure in which the end face of 13b is covered with the light emitting layer 13c is formed.

[Formation of electron transport layer]
Next, the electron transport layer 13d is formed on the light emitting layer 13c. The electron transport layer 13d is formed by a transfer method. That is, as shown in FIG. 15E, first, the transfer substrate 30 is placed in a state in which the light emitting layer 13c and the transfer layer 33 made of an organic material to be the electron transport layer 13d are arranged to face each other. The transfer layer 33 is patterned on the photothermal conversion layer 34 in a predetermined region P1 corresponding to the region where the electron transport layer 13d is formed.

  Next, the laser beam L is irradiated from the substrate 31 side. The photothermal conversion layer 34 absorbs the irradiation energy of the laser light L, and using the heat, the transfer layer 33 made of an organic material to be the electron transport layer 13d is thermally transferred onto the light emitting layer 13c. Thereby, as shown in FIG. 15F, the electron transport layer 13d is patterned at a position corresponding to the predetermined region P1. Thus, the organic layer 13 can be formed.

<Effect>
The seventh embodiment of the present invention has the same effect as that of the second embodiment.

8). Application Examples of Display Device Application examples of the display device described in the first, third, and fifth embodiments will be described. The display device according to each of the first, third, and fifth embodiments includes a video signal input from the outside, such as a television device, a digital camera, a notebook personal computer, a mobile terminal device such as a mobile phone, or a video camera. The generated video signal can be applied to display devices of electronic devices in various fields that display images or videos.

(module)
The display device according to each of the first, third, and fifth embodiments is incorporated into various electronic devices such as application examples 1 to 5 described later, for example, as a module illustrated in FIG. In the display area 80 of the module, a plurality of organic EL elements 21R, 21G and 21B are arranged in a matrix. In the display region 80, a plurality of scanning lines and a plurality of signal lines are wired vertically and horizontally, and at each intersection of the scanning lines and the plurality of signal lines, an organic EL element 21, a switching TFT, a drive A pixel driving circuit composed of a TFT for the purpose is provided. In the peripheral area of the display area 80, a signal line driving circuit 90 for supplying a video signal corresponding to luminance information to the signal lines and a scanning line driving circuit 100 for scanning and driving the scanning lines are provided.

  In this module, for example, a region 210 exposed from the sealing substrate 19 and the adhesive layer is provided on one side of the substrate 11, and wirings of the signal line driving circuit 90 and the scanning line driving circuit 100 are extended to the exposed region 210. Thus, external connection terminals (not shown) are formed. The external connection terminal may be provided with a flexible printed circuit (FPC) 220 for signal input / output.

(Application example 1)
FIG. 17 shows the appearance of a television device to which the display device according to the first, third, and fifth embodiments is applied. The television apparatus includes, for example, a video display screen unit 300 including a front panel 310 and a filter glass 320. The video display screen unit 300 is a display device according to each of the first, third, and fifth embodiments. It is comprised by.

(Application example 2)
FIG. 18 shows the appearance of a digital camera to which the display device according to the first, third, and fifth embodiments is applied. The digital camera includes, for example, a flash light emitting unit 410, a display unit 420, a menu switch 430, and a shutter button 440. The display unit 420 is a display according to the first, third, and fifth embodiments. It is comprised by the apparatus.

(Application example 3)
FIG. 19 shows the appearance of a notebook personal computer to which the display devices according to the first, third, and fifth embodiments are applied. The notebook personal computer has, for example, a main body 510, a keyboard 520 for inputting characters and the like, and a display unit 530 for displaying an image. The display unit 530 includes first, third, and fifth display units. The display device according to the embodiment is configured.

(Application example 4)
FIG. 20 shows the appearance of a video camera to which the display device according to the first, third, and fifth embodiments is applied. This video camera has, for example, a main body 610, a subject shooting lens 620 provided on the front side surface of the main body 610, a start / stop switch 630 at the time of shooting, and a display 640. Reference numeral 640 denotes a display device according to the first, third, and fifth embodiments.

(Application example 5)
FIG. 21 shows an appearance of a mobile phone to which the display device according to each of the first, third, and fifth embodiments is applied. For example, this mobile phone is obtained by connecting an upper housing 710 and a lower housing 720 with a connecting portion (hinge portion) 730, and includes a display 740, a sub-display 750, a picture light 760, and a camera 770. Yes. The display 740 or the sub-display 750 is constituted by the display device according to the first, third and fifth embodiments.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples. In the following examples, specific examples of the present invention, and manufacturing procedures of organic EL panels as comparative examples for these examples, and evaluation results thereof will be described.

<Example 1>
In Example 1, an organic EL panel was manufactured according to the above-described embodiment. The manufacturing procedure will be described below.

[Formation of anode and insulating layer]
First, an aluminum-neodymium (10%) anode (first electrode 12) having a thickness of 120 nm was formed on a 0.7 mm thick TFT substrate 11.

Next, the anode was patterned under the following conditions by photolithography and etching.
Number of pixels: horizontal 320 x vertical 240 (pieces)
Pixel pitch: horizontal 0.3mm x vertical 0.3mm

  Next, the luminescent region of 225 μm × 75 μm per color was formed by patterning the insulating layer 18 on the anode by photolithography using polyimide.

  Next, the organic layer 13 (B) corresponding to the B light emitting region, the organic layer 13 (G) corresponding to the G light emitting region, and the organic layer 13 (R) corresponding to the R light emitting region in this order are as follows: It formed as follows.

[Formation of organic layer 13 (B)]
An organic layer 13 (B) corresponding to the light emitting region of B was formed as follows. In forming the organic layer 13 (B), the mask used for forming each layer constituting the organic layer 13 (B) was as follows.

Formation of hole injection layer 13a Use of mask with opening size of 245 μm × 95 μm Formation of hole transport layer 13b Use of mask with opening size of 245 μm × 95 μm Formation of light emitting layer 13c Use of mask with opening size of 250 μm × 100 μm Electron transport layer 13d Use a mask with an opening size of 250μm × 100μm

[Formation of Hole Injection Layer 13a]
First, using a mask having an opening size of 245 μm × 95 μm, a film of the compound represented by the formula (1) is formed on the anode as a hole injection layer 13a by a vacuum deposition method with a film thickness of 15 nm (deposition rate 0). .2 to 0.4 / sec).

[Formation of hole transport layer]
Next, α-NPD (N, N′-bis (1-naphthyl) − is formed as a hole transport layer 13b on the hole injection layer 13a by a vacuum deposition method using a mask having an opening size of 245 μm × 95 μm. A film of N, N′-diphenyl [1,1′-biphenyl] -4,4′-diamine) was formed at a thickness of 130 nm (deposition rate: 1.0 to 1.2 / sec).

[Formation of light emitting layer (B)]
Next, the light emitting layer 13c was formed by a vacuum evaporation method using a mask having an opening size of 250 μm × 100 μm. In the formation of the light emitting layer 13c, ADN (9,10-di (2-naphthyl) anthracene) was used as a host material, and BD-052x (Idemitsu Kosan Co., Ltd .: trade name) was used as a dopant. These materials were formed into a total film thickness of 32 nm by vacuum deposition so that the dopant concentration was 5% in terms of the film thickness ratio.

[Formation of electron transport layer]
Next, an Alq3 (8-hydroxyquinoline aluminum) film was formed to a thickness of 18 nm by a vacuum deposition method using a mask having an opening size of 250 μm × 100 μm.

[Formation of organic layer 13 (G)]
An organic layer 13 (G) corresponding to the G light emitting region was formed as follows. In forming the organic layer 13 (G), the mask used for forming each layer constituting the organic layer 13 (G) was as follows.

Formation of hole injection layer 13a Use of mask with opening size of 245 μm × 95 μm Formation of hole transport layer 13b Use of mask with opening size of 245 μm × 95 μm Formation of light emitting layer 13c Use of mask with opening size of 250 μm × 100 μm Electron transport layer 13d Use a mask with an opening size of 250μm × 100μm

[Formation of Hole Injection Layer 13a]
First, using a mask having an opening size of 245 μm × 95 μm by a vacuum deposition method, a film of the compound represented by (formula 1) is formed on the anode as a hole injection layer 13a with a film thickness of 15 nm (deposition rate 0). .2 to 0.4 / sec).

[Formation of hole transport layer]
Next, α-NPD (N, N′-bis (1-naphthyl) − is formed as a hole transport layer 13b on the hole injection layer 13a by a vacuum deposition method using a mask having an opening size of 245 μm × 95 μm. N, N′-diphenyl [1,1′-biphenyl] -4,4′-diamine) was formed to a thickness of 170 nm (deposition rate: 1.0 to 1.2 / sec).

[Formation of light emitting layer (G)]
Next, the light emitting layer 13c was formed by a vacuum evaporation method using a mask having an opening size of 250 × 100 μm. In the formation of the light emitting layer 13c, ADN (9,10-di (2-naphthyl) anthracene) was used as a host material, and a compound represented by the formula (2) was used as a dopant. These materials were formed into a total film thickness of 28 nm by a vacuum deposition method so that the dopant concentration was 6% in terms of the film thickness ratio.

[Formation of electron transport layer]
Next, a film of Alq3 (8-hydroxyquinoline aluminum) was formed to a thickness of 40 nm by a vacuum evaporation method using a mask having an opening size of 250 μm × 100 μm.

[Formation of organic layer 13 (R)]
An organic layer 13 (R) corresponding to the R emission region was formed as follows. In forming the organic layer 13 (R), the mask used for forming each layer constituting the organic layer 13 (R) was as follows.

Formation of hole injection layer 13a Use of mask with opening size of 245 μm × 95 μm Formation of hole transport layer 13b Use of mask with opening size of 245 μm × 95 μm Formation of light emitting layer 13c Use of mask with opening size of 250 μm × 100 μm Electron transport layer 13d Use a mask with an opening size of 250μm × 100μm

[Formation of Hole Injection Layer 13a]
First, using a mask having an opening size of 245 μm × 95 μm, a film of the compound represented by the formula (1) is formed on the anode as a hole injection layer 13a by a vacuum deposition method with a film thickness of 15 nm (deposition rate 0). .2 to 0.4 / sec).

[Formation of hole transport layer]
Next, α-NPD (N, N′-bis (1-naphthyl) − is formed as a hole transport layer 13b on the hole injection layer 13a by a vacuum deposition method using a mask having an opening size of 245 μm × 95 μm. N, N′-diphenyl [1,1′-biphenyl] -4,4′-diamine) was formed to a thickness of 190 nm (deposition rate: 1.0 to 1.2 / sec).

[Formation of light emitting layer (R)]
Next, the light emitting layer 13c was formed by a vacuum evaporation method using a mask having an opening size of 250 × 100 μm. In the formation of the light emitting layer 13c, rubrene is used as a host material, and dibenzo [f, f ′] diindene [1,2,3-cd: 1 ′, 2 ′, 3 ′ represented by the formula (3) is used as a dopant. -Im] perylene derivative was used. These materials were formed into a total film thickness of 43 nm by a vacuum deposition method so that the dopant concentration was 1% in terms of the film thickness ratio.

[Formation of electron transport layer]
Next, a film of Alq3 (8-hydroxyquinoline aluminum) was formed to a thickness of 50 nm by a vacuum evaporation method using a mask having an opening size of 250 × 100 μm.

[Formation of cathode]
A two-layered cathode (second electrode 15) was formed on the organic layer 13 and insulating layer 18 formed as described above. First, a LiF film having a thickness of about 0.3 nm (0.01 nm / sec or less) was formed as the first layer of the cathode by a vacuum deposition method. Next, as the second layer of the cathode, an MgAg film was formed to a thickness of 10 nm (0.01 nm / sec or less) by vacuum deposition.

[Formation of protective film]
Next, a SiO ₂ film as a protective layer 17 was formed to a thickness of 50 nm so as to cover the organic layer 13 and the entire cathode by vacuum deposition.

  Thus, an organic EL panel (pixel number: horizontal 320 × vertical 240, pixel pitch: horizontal 0.3 × vertical 0.3 mm) that independently emits light of three colors of RGB was produced.

[Evaluation]
With respect to the organic EL element 21 of the organic EL panel manufactured as described above, current-voltage characteristics from 0 V to 7 V were measured. As a result, in the organic EL element 21B, the threshold voltage was 3.0V. Further, in the organic EL element 21G, the threshold voltage was 3.2V. In the organic EL element R, the threshold voltage was 3.5V.

In order to evaluate the leakage current, the current density per pixel at a voltage 0.2 V lower than the threshold voltage was measured. As a result, in the organic EL element 21B, the current density obtained by measurement was 2.8 × 10 ⁻¹⁰ [mA / cm ² ]. In the organic EL element 21G, the current density obtained by measurement was 2.0 × 10 ⁻¹⁰ [mA / cm ² ]. In the organic EL element 21R, the current density obtained by the measurement was 1.3 × 10 ⁻¹⁰ [mA / cm ² ].

  Further, in the organic EL panel manufactured by this method, no light emission unevenness due to leakage current was observed even in a low luminance region of 3 nit or less.

<Comparative Example 1>
The organic layer 13 was formed only with a mask having an opening size of 245 μm × 95 μm by vacuum deposition. That is, in forming the organic layer 13 (B), the organic layer 13 (G), and the organic layer 13 (R), the masks used for forming each layer were as follows.

Formation of hole injection layer 13a Use of mask with opening size of 245 μm × 95 μm Formation of hole transport layer 13b Use of mask with opening size of 245 μm × 95 μm Formation of light emitting layer 13c Use of mask with opening size of 245 μm × 95 μm Electron transport layer 13d Use a mask with an opening size of 245μm × 95μm

  Except for the above points, in the same manner as in Example 1, an organic EL panel that independently emits the three colors of RGB (number of pixels: horizontal 320 × vertical 240 (pieces), pixel pitch: horizontal 0.3 mm × vertical 0) 3 mm was produced.

[Evaluation]
With respect to the organic EL element 21 of the organic EL panel manufactured as described above, current-voltage characteristics from 0 V to 7 V were measured. As a result, the threshold voltage did not change. That is, in the organic EL element 21B, the threshold voltage was 3.0V. Further, in the organic EL element 21G, the threshold voltage was 3.2V. In the organic EL element R, the threshold voltage was 3.5V.

In order to evaluate the leakage current, the current density per pixel at a voltage 0.2 V lower than the threshold voltage was measured. As a result, in the organic EL element 21B, the current density obtained by measurement was 1.2 × 10 ⁻⁸ [mA / cm ² ]. In the organic EL element 21G, the current density obtained by the measurement was 7.2 × 10 ⁻⁹ [mA / cm ² ]. In the organic EL element 21R, the current density obtained by measurement was 8.3 × 10 ⁻⁹ [mA / cm ² ].

  That is, comparing the result of Comparative Example 1 with the result of Example 1 described above, it was found that the leakage current was reduced by one digit or more in Example 1 compared to Comparative Example 1.

  Further, in the organic EL panel of Comparative Example 1, light emission unevenness due to leakage current was confirmed in a low luminance region of 3 nit or less.

9. Other Embodiments The present invention is not limited to the above-described embodiments of the present invention, and various modifications and applications are possible without departing from the spirit of the present invention. For example, the numerical values, structures, shapes, materials, and the like given in the above-described embodiments are merely examples, and different numerical values, structures, shapes, materials, and the like may be used as necessary.

  For example, in the first to seventh embodiments, the configuration of the organic layer 13 is the hole injection layer 13a / the hole transport layer 13b / the light emitting layer 13c / the electron transport layer 13d, but is not limited thereto. Absent. If necessary, the number of layers constituting the organic layer may be increased or decreased as appropriate. In this case, the other end surface of the layer causing the leak is covered by forming another layer having a higher resistance than the layer causing the leak along the end surface of the layer causing the leak having a low resistance. Accordingly, the leakage current can be suppressed by adopting a structure in which the end surface of the layer causing the leakage does not contact the second electrode.

  For example, in the first to seventh embodiments, the top emission type display device has been described, but the present invention can also be applied to a bottom emission type (bottom emission type) display device. Moreover, TFT is connected to each organic EL element, and it is not limited to the active matrix system which controls light emission of each organic EL element independently by this TFT. For example, it can be applied to a passive matrix system.

  In the second, fourth, and sixth embodiments, examples in which each layer constituting the organic layer 13 is formed by a vacuum deposition method will be described. In the seventh embodiment, each layer constituting the organic layer 13 is transferred. Although the example formed by a method was demonstrated, it is not limited to this.

  For example, the organic layer 13 may be formed by a printing method. At this time, the range of the printing pattern of the layers constituting the organic layer 13 is appropriately set for each constituent layer. That is, a layer that causes a leakage current having a low resistance is set as a narrow-range printed pattern. Then, a layer having a higher resistance than the layer causing the leak current is set to a wide range of print patterns. As a result, a structure in which the end surface of the layer causing the leak current is covered with a layer that does not cause the leak current can be formed, and the leak current can be suppressed.

  In the second, fourth, and sixth embodiments, an example in which all the layers constituting the organic layer 13 are formed by a vacuum deposition method will be described. In the seventh embodiment, the organic layer 13 is configured. Although an example in which all the layers are formed by the transfer method has been described, the present invention is not limited to this.

  For example, each layer of the organic layer 13 may be formed using both the vacuum deposition method and the transfer method. That is, for example, the hole injection layer, the hole transport layer, and the electron transport layer may be formed by a vacuum deposition method, and only the light emitting layer may be formed by a transfer method. Of course, it may be formed using both the vacuum evaporation method and the printing method, or may be formed using both the transfer method and the printing method, or the vacuum evaporation method, the printing method, and the transfer method.

  In the first to seventh embodiments, examples in which the organic layer 13 is arranged in a matrix have been described. However, the present invention is not limited to this. For example, the present invention can be applied to a display device configured such that organic layers corresponding to different emission colors (for example, R, G, and B) are arranged in a stripe shape. In the formation of the organic layer configured as described above, a striped mask is used, but even when this striped mask is used, a leak is generated by changing the opening size of the mask according to each layer constituting the organic layer. It is possible to form a structure that covers the end surface of the low-resistance layer that causes the above.

  In the seventh embodiment, the transfer layer is patterned and then thermally transferred. However, the transfer layer may be formed on the entire surface of the substrate to selectively change the laser irradiation range.

  Further, if necessary, the display device can be configured by combining the organic EL elements of the first and third embodiments. For example, the display device can be configured with the organic EL element 21R as the configuration of the first embodiment and the organic EL element 21G and the organic EL element 21B as the configuration of the third embodiment.

DESCRIPTION OF SYMBOLS 11 ... Substrate 13 ... Organic layer 13a ... Hole injection layer 13b ... Hole transport layer 13c ... Light emitting layer 13b ... Transfer layer 13d ... Electron transport layer 15 ... Electrode 17 ... Protective film 18 ... Insulating layer 19 ... Sealing substrate 30 ... Transfer substrate 33 ... Transfer layer 34 ... Photothermal conversion layer 35 ... Oxidation protective layer

Claims (10)

A first electrode;
A second electrode;
An organic layer provided between the first electrode and the second electrode and made of an organic material;
The organic layer is composed of a plurality of layers including a light emitting layer,
A display device in which an end face of a first layer composed of at least one of the plurality of layers is covered with a second layer composed of at least one of the layers positioned above the first layer. . The display device according to claim 1, wherein the second layer is a layer having higher resistance than the first layer. The organic layer has a hole injection layer and a hole transport layer in addition to the light emitting layer,
The first layer includes at least one of the hole injection layer and the hole transport layer,
The display device according to claim 1, wherein the second layer includes the light emitting layer. The display device according to claim 1, wherein a material configuration of each layer constituting the organic layer is different for each emission color. The display device according to claim 1, wherein a thickness configuration of each layer constituting the organic layer is different for each emission color. A display device having a first electrode, a second electrode, and an organic layer that is provided between the first electrode and the second electrode and that includes a plurality of layers that are formed of an organic material and includes a light-emitting layer. A manufacturing method of
The organic layer forming step includes a first step of forming a first layer composed of at least one of the plurality of layers,
And a second step of forming, along the end face of the first layer, a second layer comprising at least one of the layers positioned above the first layer. The method for manufacturing a display device according to claim 6, wherein the second layer is a layer having a higher resistance than the first layer. In the first step, the formation of the first layer is performed by depositing an organic material to be the first layer in a first deposition range,
In the second step, the formation of the second layer is performed by depositing an organic material to be the second layer in a second deposition range wider than the first deposition range. The manufacturing method of the display apparatus of description. The organic layer has a hole injection layer and a hole transport layer in addition to the light emitting layer,
The first layer includes at least one of the hole injection layer and the hole transport layer,
The method for manufacturing a display device according to claim 6, wherein the second layer includes the light emitting layer. The method for manufacturing a display device according to claim 6, wherein the organic layer forming step is performed by at least one of a vapor deposition method, a transfer method, and a printing method.

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