JP2005242339A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device that can reduce variation of a light emission spectrum depending upon an angle at which a light guide-out surface is viewed and stop impurity diffusion from a substrate to a thin-film transistor. <P>SOLUTION: The light emitting device is provided with the substrate, a 1st insulating layer provided on the substrate, the transistor provided on the 1st insulating layer, and a 2nd insulating layer having a 1st opening provided so that the transistor is covered and the substrate is exposed, a light emitting element being provided inside the 1st opening. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an active matrix light-emitting device, and more particularly to a structure of a portion from which light emission is extracted.

  A light-emitting device using light emission from an electroluminescence element (light-emitting element) is a device that has attracted attention as a display device with a high viewing angle and low power consumption.

  There are an active matrix type and a passive matrix type as a driving method of a light-emitting device mainly used for display. An active matrix light-emitting device with a driving method can control light emission and non-light emission for each light-emitting element. Therefore, it can be driven with lower power consumption than a passive matrix light-emitting device, and is suitable not only as a display portion of a small electrical appliance such as a mobile phone but also as a display portion of a large-sized television receiver or the like. .

  In the active matrix light-emitting device, a circuit for controlling driving of each light-emitting element is provided for each light-emitting element. The circuit and the light-emitting element are arranged on the substrate so that extraction of emitted light to the outside is not hindered by the circuit. In addition, a light-transmitting insulating layer is stacked in a portion overlapping with the light-emitting element, and light emission is emitted outside through the insulating layer. These insulating layers are provided to form circuit elements such as transistors and capacitors, which are components of the circuit, or wiring.

  By the way, when light emission passes through the laminated insulating films, the light emission may cause multiple interference due to the difference in the refractive index of each insulating layer. As a result, the emission spectrum changes depending on the angle at which the light emission surface is viewed, and the visibility of the image displayed on the light emitting device is deteriorated.

  In addition, a reduction in image visibility caused by a difference in refractive index between layers also occurs in a passive matrix light-emitting device. For example, Patent Document 1 raises a problem that external light and light emission are reflected at an interface due to a difference in refractive index of each layer constituting a light emitting element, and visibility is deteriorated, so that the element structure can be solved. We have proposed light-emitting elements that have been devised.

JP-A-7-21458

  An object of the present invention is to provide a light emitting device capable of reducing a change in an emission spectrum depending on an angle at which a light emission extraction surface is viewed. It is another object of the present invention to provide a light emitting device capable of reducing a change in an emission spectrum depending on an angle at which a light emission extraction surface is viewed and preventing impurity diffusion from a light emitting element to a thin film transistor.

  The light emitting device of the present invention is provided so as to cover a substrate, a first insulating layer provided on the substrate, a transistor provided on the first insulating layer, the transistor, and to expose the substrate. And a second insulating layer having a first opening, and a light emitting element is provided inside the first opening.

  Here, the transistor and the light emitting element are electrically connected via a connection portion. The connecting portion is connected to the transistor through a contact hole that penetrates the second insulating layer.

  Note that the second insulating layer may be a single layer or a multilayer in which a plurality of layers made of different materials are stacked. Preferably, the second insulating layer is a layer including a layer made of silicon nitride containing oxygen. is there.

  The light emitting device of the present invention is provided so as to cover a substrate, a first insulating layer provided on the substrate, a transistor provided on the first insulating layer, the transistor, and to expose the substrate. And a second insulating layer having a first opening, and a first electrode, a light-emitting layer, and a second electrode are sequentially stacked on the substrate inside the first opening. It is characterized by that.

  Here, the transistor and the light emitting element are electrically connected via a connection portion. The connecting portion is connected to the transistor through a contact hole that penetrates the second insulating layer.

  Note that the second insulating layer may be a single layer or a multilayer in which a plurality of layers made of different materials are stacked. Preferably, the second insulating layer is a layer including a layer made of silicon nitride containing oxygen. is there.

  The light emitting device of the present invention is provided so as to cover a substrate, a first insulating layer provided on the substrate, a transistor provided on the first insulating layer, the transistor, and to expose the substrate. A second insulating layer having a first opening, a third insulating layer covering the first opening and the second insulating layer, and inside the first opening. On the said board | substrate, the 1st electrode, the light emitting layer, and the 2nd electrode are laminated | stacked in order.

  Here, the transistor and the light emitting element are electrically connected via a connection portion. The connecting portion is connected to the transistor through a contact hole that penetrates the second insulating layer.

  Note that the second insulating layer may be a single layer or a multilayer in which a plurality of layers made of different materials are stacked. Preferably, the second insulating layer is a layer including a layer made of silicon nitride containing oxygen. is there. The third insulating layer is preferably a layer made of silicon nitride containing oxygen.

  The light emitting device of the present invention is provided so as to cover a substrate, a first insulating layer provided on the substrate, a transistor provided on the first insulating layer, the transistor, and to expose the substrate. A second insulating layer having the first opening, a first electrode covering the first opening, and a partition wall provided with a second opening so that the first electrode is exposed And a light emitting layer provided on the first electrode exposed in the second opening, and a second electrode provided on the light emitting layer.

  Here, the transistor and the light emitting element are electrically connected via a connection portion. The connecting portion is connected to the transistor through a contact hole that penetrates the second insulating layer.

  Note that the second insulating layer may be a single layer or a multilayer in which a plurality of layers made of different materials are stacked. Preferably, the second insulating layer is a layer including a layer made of silicon nitride containing oxygen. is there. The third insulating layer is preferably a layer made of silicon nitride containing oxygen.

  According to the present invention, it is possible to obtain a light emitting device in which a change in emission spectrum depending on an angle at which the light emission extraction surface is viewed is reduced.

  In addition, a change in the emission spectrum depending on the viewing angle of the emission extraction surface is reduced, whereby a display device that can provide an image with excellent visibility can be obtained.

  Hereinafter, one embodiment of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention is not construed as being limited to the description of this embodiment mode.

(Embodiment 1)
The light-emitting device of the present invention will be described with reference to FIG.

  On the substrate 11, an insulating layer 12 including two layers of an insulating layer 12a and an insulating layer 12b is provided. A staggered transistor 16 including a semiconductor layer 13, a gate insulating layer 14, and a gate electrode 15 is provided on the insulating layer 12b.

  The transistor 16 is covered with an insulating layer 17 having a first opening. The insulating layer 17 includes two layers, an insulating layer 17a (lower layer) and an insulating layer 17b (upper layer). However, the present invention is not limited to this, and a single layer or a multilayer of three or more layers may be used. The first opening also penetrates the gate insulating layer 14 and the insulating layer 12 and reaches the substrate 11. Accordingly, a part of the substrate 11 is exposed from the first opening.

  The insulating layer 17 and the first opening are covered with the insulating layer 18, and the insulating layer 18 and the substrate 11 overlap and are in contact with each other inside the first opening.

  The light emitting element 24 is formed by sandwiching the light emitting layer 22 between the first electrode 20 and the second electrode 23, and is provided on the insulating layer 18. The first electrode 20 and the insulating layer 18 are overlapped and in contact with each other.

  The transistor 16 and the light emitting element 24 are electrically connected via a connecting portion 19a made of a conductor. The connecting portion 19 a is provided on the insulating layer 18 and reaches the semiconductor layer 13 through a contact hole that penetrates the insulating layers 17 and 18. Further, a part of the connection portion 19 a is in contact with the first electrode 20, whereby the connection portion 19 a and the first electrode 20 are electrically connected.

  The connecting portion 19a, the wiring 19b, the insulating layer 18 and the like are covered with a partition wall layer 21 having a second opening provided so that a part of the first electrode 20 is exposed. In the second opening, a light emitting layer 22 is provided on the first electrode 20, and a second electrode 23 is provided on the light emitting layer 22. Thus, the portion where the first electrode 20, the light emitting layer 22, and the second electrode 23 are stacked functions as the light emitting element 24. Note that the light-emitting layer 22 is a layer that includes a light-emitting substance and includes a single layer or multiple layers.

  In this embodiment, the substrate 11 is made of a material that can transmit visible light such as glass. In addition, a flexible resin such as plastic may be used as the substrate 11. In addition, any substrate that has translucency and functions as a support for supporting the transistor 16 and the light-emitting element 24 can be used as the substrate 11.

  The insulating layer 12a and the insulating layer 12b are layers made of a material that can prevent diffusion of impurities from the substrate 11. In particular, the insulating layer 12a is preferably a layer having a function of preventing impurity diffusion. The insulating layer 12b preferably has a function of preventing impurity diffusion and has a small stress difference from the semiconductor layer 13. An example of such a layer is a layer made of silicon oxide. Note that the layer made of silicon oxide may contain several percent or less of nitrogen. Note that the insulating layer 12 is not necessarily constituted by two layers. For example, when the impurity diffusion from the substrate 11 can be prevented only by the insulating layer 12a, the insulating layer 12b is provided between the semiconductor layer 13 and the insulating layer 12a. It does not necessarily have to be provided.

  The insulating layer 17a is preferably formed using silicon nitride containing 5 to 6% oxygen element when analyzed by Rutherford backscattering method / hydrogen forward scattering method (RBS / HFS). The layer formed in this manner contains hydrogen, and hydrogen treatment can be performed using the hydrogen. It also has a function of preventing impurity diffusion into the transistor.

  Further, the insulating layer 18 is preferably formed of a material having low moisture permeability, a refractive index higher than that of the substrate 11 and a refractive index lower than that of the first electrode 20. The insulating layer 18 is particularly preferably formed using silicon nitride containing 5 to 6% oxygen element when analyzed by Rutherford backscattering method / hydrogen forward scattering method (RBS / HFS). The layer formed in this way has a high impurity stopping capability and is difficult to transmit moisture. Accordingly, diffusion of impurities from the light emitting element 24 to the transistor 16 can be prevented. In addition, when the insulating layer 17 is formed of a material with high moisture permeability, the insulating layer 17 also has a function of preventing water from being diffused into the light emitting element 24 through the insulating layer 17. Note that the insulating layer 18 is not necessarily provided when there is no particular problem of moisture mixing into the light-emitting element.

  The first electrode 20 is made of indium tin oxide (ITO), ITO containing silicon oxide, IZO (Indium Zinc Oxide) in which indium oxide is mixed with 2 to 20% zinc oxide (ZnO). ) Or the like, and a conductive material that can transmit visible light may be used.

  The insulating layer 17b may be a multilayer or a single layer. The insulating layer 17b may be made of any inorganic material such as silicon oxide, siloxane, or silicon nitride, or an organic material such as acrylic or polyimide, or may include both an inorganic material or an organic material. Good. In any case, an insulator may be used. Note that the insulating layer 17b preferably includes a layer made of a self-flattening material such as siloxane or acrylic so that the surface of the insulating layer 18 is flat. However, the planarization of the surface of the insulating layer 17b is not limited to using a substance having self-flatness, and may be performed by a polishing method.

  Moreover, the light emitting layer 22 may be made of either an organic material or an inorganic material, or may include both an inorganic material and an organic material.

  Note that there is no particular limitation on the structure of the transistor 16 in the light-emitting device of the present invention. A single gate type or a multi-gate type may be used. Further, a single drain structure, an LDD (Lightly Doped Drain) structure, or a structure in which an LDD region and a gate electrode overlap each other may be used.

  FIG. 2 is a top view of the light emitting device of the present invention. In FIG. 2, a partial cross section of the portion represented by the broken line A-A ′ is represented by the cross sectional view of FIG. 1. Accordingly, components corresponding to those shown in FIG. 1 are denoted by the same reference numerals as those in FIG. That is, 13 is a semiconductor layer, 15 is a gate electrode, 19b is a wiring, and 19a is a connection portion. Reference numeral 20 denotes a first electrode, and reference numeral 23 denotes a partition layer. Further, although not shown in FIG. 1, 19c, 29a, and 29b are wirings, and 27 and 28 are transistors.

  In the light emitting device, light emitted from the light emitting element 24 is emitted to the outside through the first electrode 20, the insulating layer 18, and the substrate 11 in this order.

  In the light-emitting device of the present invention described above, reflection of light emission generated in the process of taking out light emitted from the light-emitting device is reduced, and impurity diffusion from the substrate to the transistor can be sufficiently prevented. Furthermore, in the light emitting device of the present invention, the reflection of light emission generated in the process of extracting light emission from the light emitting device is reduced, so that multiple interference due to the reflected light is suppressed. As a result of the suppression of the multiple interference, the change in the emission spectrum depending on the angle at which the emission extraction surface is viewed is reduced, and the visibility of the image displayed on the light emitting device is improved.

(Embodiment 2)
In this embodiment mode, a method for manufacturing the light-emitting device of the present invention shown in FIGS. 1 and 2 will be described with reference to FIGS.

  After the insulating layers 12a and 12b are sequentially stacked on the substrate 11, the semiconductor layer 13 is further stacked on the insulating layer 12b.

  Next, the semiconductor layer 13 is processed into a desired shape. The processing may be performed by etching the semiconductor layer 13 using a resist mask.

  Next, a gate insulating layer 14 that covers the semiconductor layer 13, the insulating layer 12 b, and the like is formed, and a conductive layer is stacked over the gate insulating layer 14.

  Next, the conductive layer is processed into a desired shape to form the gate electrode 15. Here, wirings 29a and 29b (FIG. 2) are also formed together with the gate electrode 15. Note that the processing may be performed by etching the conductive layer using a resist mask.

  Next, a high concentration impurity is added to the semiconductor layer 13 using the gate electrode 15 as a mask. Thus, the transistor 16 including the semiconductor layer 13, the gate insulating layer 14, and the gate electrode 15 is manufactured.

  Note that the manufacturing process of the transistor 16 is not particularly limited and may be changed as appropriate so that a transistor having a desired structure can be manufactured.

Next, an insulating layer 17a that covers the gate electrode 15, the wirings 29a and 29b, the gate insulating layer 14, and the like is formed. In this embodiment, the insulating layer 17a is formed using silicon nitride containing 5 to 6% oxygen element when analyzed by Rutherford backscattering method / hydrogen forward scattering method (RBS / HFS). Note that the layer made of silicon nitride containing 5 to 6% oxygen element includes, for example, monosilane (SiH ₄ ), ammonia (NH ₃ ), nitrous oxide (N ₂ O), and hydrogen (H ₂ ), respectively. : The gas mixed so as to have a flow ratio of 10: 2: 40 can be used as a raw material, and can be formed by plasma CVD.

  Next, an insulating layer 17b that covers the insulating layer 17a is formed. In this embodiment, the insulating layer 17b is formed using an inorganic material having self-flatness such as siloxane. However, the present invention is not limited to this, and an organic material having self-flatness may be used. The insulating layer 17b does not necessarily need to be formed of a substance having self-flatness, and may be made of only a substance having no self-flatness.

  Next, the insulating layer 17 and the like are etched to form a first opening that penetrates the insulating layer 17 and reaches the substrate 11. As a result, the substrate 11 is exposed from the first opening.

  Next, an insulating layer 18 that covers the first opening and the insulating layer 17 is formed. In this embodiment, the insulating layer 17a is formed using silicon nitride containing 5 to 6% oxygen element when analyzed by Rutherford backscattering method / hydrogen forward scattering method (RBS / HFS).

  Next, it heat-processes at the temperature of 350 to 500 degreeC. Accordingly, hydrogen contained in the insulating layer 17a and the like diffuses, and the transistor 16 can be hydrogenated. Note that this step may be performed after the insulating layer 17a is formed and before the insulating layer 17b is formed.

  Next, after forming a conductive layer 19 that covers the insulating layer 18 and the like, the conductive layer 19 is processed into a desired shape to form connection portions 19a, wirings 19b and 19c, a film 19d, and the like. At this time, the substrate 11 is exposed in the first opening.

  Next, after forming a light-transmitting conductive layer so as to cover the connection portion 19 a and the like, the conductive layer is processed to form the first electrode 20. In the present embodiment, the first electrode 20 is processed into a shape such that part of the first electrode 20 is in contact with the connection portion 19 a and covers the opening provided in the insulating layer 18. At this time, the first electrode 20 is in contact with the substrate 11.

  Next, a partition wall layer 21 having an opening so as to expose a part of the first electrode 20 and covering the connection portion 19a, the insulating layer 18, and the like is formed. Here, the partition wall layer 21 may be formed by processing a photosensitive resin material into a desired shape by exposure / development, or after forming a layer made of an inorganic or organic material having no photosensitivity. It may be formed by etching into a desired shape.

  Next, the light emitting layer 22 that covers the first electrode 20 exposed from the partition wall layer 21 is formed. The light emitting layer 22 may be formed by any method such as a vapor deposition method, an ink jet method, or a spin coating method. In the case where the surface of the substrate 11 has irregularities, a layer made of a polymer material in which polystyrene sulfonic acid (PSS) and polyethylene dioxythiophene (PEDOT) are mixed is provided on a part of the light emitting layer 22. Unevenness can be relaxed.

  In this example, a light-emitting device to which the present invention is applied will be described. However, the structure of the light-emitting device of the present invention and the substances constituting the light-emitting device are not limited to those shown in this embodiment.

  The light emitting device of this example is the light emitting device of the present invention having a cross-sectional structure as shown in FIG.

  In the present embodiment, the light emitting layer 22 which is a constituent element of the light emitting element 24 includes a plurality of layers. The plurality of layers are formed by combining layers made of a substance selected from a substance having a high carrier transporting property and a substance having a high carrier injecting property, and partly contains a substance having a high light emitting property. The substance constituting the light emitting layer 22 may be inorganic or organic. In the case of an organic substance, it may be a low molecule or a polymer.

Here, as the light-emitting substance, 4-dicyanomethylene-2-methyl-6- (1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (abbreviation: DCJT), 4- Dicyanomethylene-2-t-butyl-6- (1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (abbreviation: DPA), perifuranthene, 2,5-dicyano-1, 4-bis (10-methoxy-1,1,7,7-tetramethyljulolidyl-9-enyl) benzene, N, N′-dimethylquinacridone (abbreviation: DMQd), coumarin 6, coumarin 545T, tris (8 - quinolinolato) aluminum (abbreviation: Alq _3), 9,9'-bianthryl, 9,10-diphenyl anthracene (abbreviation: DPA) and 9,10-bis (2-naphthyl) anthracene ( Abbreviations: DNA) and the like can be used. Other substances may also be used.

  In addition to the singlet excited luminescent material as described above, a triplet excited material containing a metal complex or the like may be used. For example, among red light emitting pixels, green light emitting pixels, and blue light emitting pixels, a red light emitting pixel having a relatively short luminance half time is formed of a triplet excitation light emitting material, and the other It is formed of a singlet excited luminescent material. A triplet excited luminescent substance has a feature that it has a high luminous efficiency, so that less power is required to obtain the same luminance. That is, when applied to a red pixel, the amount of current flowing through the light emitting element can be reduced, so that reliability can be improved. As a reduction in power consumption, a red light-emitting pixel and a green light-emitting pixel may be formed using a triplet excitation light-emitting material, and a blue light-emitting pixel may be formed using a singlet excitation light-emitting material. By forming a green light-emitting element having high human visibility with a triplet-excited light-emitting substance, power consumption can be further reduced.

  Examples of triplet excited luminescent materials include those using metal complexes as dopants, and metal complexes having a third transition series element platinum as the central metal and metal complexes having iridium as the central metal are known. Yes. The triplet excited light-emitting substance is not limited to these compounds, and it is also possible to use a compound having the above structure and having an element belonging to Group 8 to 10 in the periodic table as a central metal.

Among substances having a high carrier transport property, a substance having a particularly high electron transport property includes, for example, tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (5-methyl-8-quinolinolato) aluminum (abbreviation: Almq _3). ), Bis (10-hydroxybenzo [h] -quinolinato) beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), or the like, And metal complexes having a benzoquinoline skeleton. As a substance having a high hole-transport property, for example, 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (abbreviation: α-NPD), 4,4′-bis [ N- (3-methylphenyl) -N-phenyl-amino] -biphenyl (abbreviation: TPD) or 4,4 ′, 4 ″ -tris (N, N-diphenyl-amino) -triphenylamine (abbreviation: TDATA) ), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenyl-amino] -triphenylamine (abbreviation: MTDATA) (ie, benzene ring-nitrogen) And a compound having a bond of In addition, among substances having a high carrier-injecting property, substances having a particularly high electron-injecting property include alkali metals or alkalis such as lithium fluoride (LiF), cesium fluoride (CsF), and calcium fluoride (CaF ₂ ). Examples include earth metal compounds. In addition, a mixture of a substance having a high electron transport property such as Alq ₃ and an alkaline earth metal such as magnesium (Mg) may be used. Examples of the material having a high hole injection property include molybdenum oxide (MoOx), vanadium oxide (VOx), ruthenium oxide (RuOx), tungsten oxide (WOx), and manganese oxide (MnOx). A metal oxide is mentioned. In addition, phthalocyanine compounds such as phthalocyanine (abbreviation: H ₂ Pc) and copper phthalocyanine (CuPC) can be given. Alternatively, a polymer material in which polystyrene sulfonic acid (PSS) and polyethylenedioxythiophene (PEDOT), which are substances having a high hole injecting property and a high hole transporting property, are mixed may be used.

  The high molecular weight organic light emitting material has higher physical strength than the low molecular weight material, and the durability of the device is high. In addition, since the film can be formed by coating, the device can be manufactured relatively easily.

  The transistor 16 is a staggered type, but may be an inverted staggered type. Further, in the case of an inverted staggered type, a so-called channel protective type having a protective layer on a semiconductor layer may be used, or a so-called channel etched type in which a part of the semiconductor layer is etched.

  The semiconductor layer 13 may be either crystalline or amorphous. Moreover, a semi-amorphous etc. may be sufficient.

The semi-amorphous semiconductor is as follows. A semiconductor having an intermediate structure between amorphous and crystalline (including single crystal and polycrystal) and having a third state that is stable in terms of free energy, has a short-range order, and has a lattice distortion. It contains a crystalline region. Further, at least a part of the region in the film contains crystal grains of 0.5 to 20 nm. The Raman spectrum is shifted to the lower wavenumber side than 520 cm ⁻¹ . In X-ray diffraction, diffraction peaks of (111) and (220) that are derived from the Si crystal lattice are observed. At least 1 atomic% or more of hydrogen or halogen is contained as a neutralizing agent for dangling bonds. It is also called a so-called microcrystalline semiconductor (microcrystal semiconductor). A silicide gas is formed by glow discharge decomposition (plasma CVD). As the silicide gas, SiH ₄ , Si ₂ H ₆ , SiH ₂ Cl ₂ , SiHCl ₃ , SiCl ₄ , SiF ₄ or the like can be used. This silicide gas may be diluted with H ₂ , or H ₂ and one or more kinds of rare gas elements selected from He, Ar, Kr, and Ne. The dilution rate is in the range of 2 to 1000 times. The pressure is generally in the range of 0.1 Pa to 133 Pa, and the power supply frequency is 1 MHz to 120 MHz, preferably 13 MHz to 60 MHz. The substrate heating temperature may be 300 ° C. or less, preferably 100 to 250 ° C. As an impurity element in the film, impurities of atmospheric components such as oxygen, nitrogen, and carbon are desirably 1 × 10 ²⁰ cm ⁻¹ or less, and in particular, the oxygen concentration is 5 × 10 ¹⁹ / cm ³ or less, preferably 1 × 10 ¹⁹ / cm ³ or less. Note that the mobility of a TFT (thin film transistor) using a semi-amorphous semiconductor is approximately 1 to 10 m ² / Vsec.

  Further, specific examples of the crystalline semiconductor layer include those made of single crystal or polycrystalline silicon, silicon germanium, or the like. These may be formed by laser crystallization, or may be formed by crystallization by a solid phase growth method using nickel or the like, for example.

  Note that in the case where the semiconductor layer is formed of an amorphous material, for example, amorphous silicon, the transistor 16 and other transistors (transistors constituting a circuit for driving a light emitting element) are all configured by N-channel transistors. It is preferable that the light-emitting device have a structured circuit. Other than that, a light-emitting device having a circuit including any one of an N-channel transistor and a P-channel transistor, or a light-emitting device including a circuit including both transistors may be used.

  The partition layer 21 preferably has a shape in which the radius of curvature continuously changes at the edge portion as shown in FIG. The partition wall layer 21 is formed using acryl, siloxane (a substance having a skeleton structure formed of a bond of silicon (Si) and oxygen (O) and containing at least hydrogen as a substituent), a resist, silicon oxide, or the like. . The partition layer 21 may be formed of any one of an inorganic film and an organic film, or may be formed using both.

  The light-emitting element 24 may have a configuration in which the first electrode 20 functions as an anode and the second electrode 23 functions as a cathode, or the first electrode 20 functions as a cathode, The electrode 23 may function as an anode. However, in the former case, the transistor 16 is a P-channel transistor, and in the latter case, the transistor 16 is an N-channel transistor.

The light emitting device of the present invention is formed by arranging a plurality of pixels including the light emitting element 24 and the transistor 16 as described above in a matrix. Note that the light-emitting layer may be configured to perform color display by forming light-emitting layers having different emission wavelength bands for each pixel. Typically, a light emitting layer corresponding to each color of R (red), G (green), and B (blue) is formed. In this case as well, by providing a filter (colored layer) that transmits light in the emission wavelength band on the light emission side of the pixel, the color purity is improved and the pixel portion is mirrored (reflected). Prevention can be achieved. By providing the filter (colored layer), it is possible to omit a circularly polarized plate that has been conventionally required, and it is possible to eliminate the loss of light emitted from the light emitting layer. Furthermore, a change in color tone that occurs when the pixel portion (display screen) is viewed obliquely can be further reduced.
In addition to providing a light emitting layer corresponding to each color and performing color display as described above, the light emitting layer may be configured to emit monochromatic or white light. In the case of using a white light emitting material, color display can be made possible by providing a filter (colored layer) that transmits light of a specific wavelength on the light emission side of the pixel.
In order to form a light emitting layer that emits white light, for example, Alq _3, Alq ₃ partially doped with Nile red, Alq _3, p-EtTAZ, TPD (aromatic diamine) are sequentially stacked by a vapor deposition method In this way, white can be obtained. Moreover, when forming a light emitting layer by the apply | coating method using spin coating, after apply | coating, it is preferable to bake by vacuum heating. For example, a poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) aqueous solution (PEDOT / PSS) is applied and fired on the entire surface, and then dye (1,1,4,4-tetraphenyl-1,3-butadiene is obtained. (TPB), 4-dicyanomethylene-2-methyl-6- (p-dimethylamino-styryl) -4H-pyran (DCM1), Nile Red, Coumarin 6 etc.) doped polyvinyl carbazole (PVK) solution is applied over the entire surface What is necessary is just to bake.

  The light emitting layer can be formed as a single layer in addition to the multilayer as described above. In this case, a 1,3,4-oxadiazole derivative (PBD) may be dispersed in polyvinyl carbazole (PVK). Further, white light emission can be obtained by dispersing 30 wt% PBD and dispersing an appropriate amount of four kinds of dyes (TPB, coumarin 6, DCM1, Nile red).

  The light emitting element which is a component of the light emitting device of the present invention emits light by being forward biased. A pixel of a display device formed using a light-emitting element can be driven by an active matrix method. In any case, each pixel emits light by applying a forward bias at a specific timing, but is in a non-light emitting state for a certain period. By applying a reverse bias during this non-light emitting time, the reliability of the light emitting element can be improved. The light emitting element has a degradation mode in which the light emission intensity decreases under a constant driving condition and a degradation mode in which the non-light emitting area is enlarged in the pixel and the luminance is apparently decreased. However, alternating current that applies a bias in the forward and reverse directions. By performing a typical drive, the progress of deterioration can be slowed, and the reliability of the light emitting device can be improved.

  The configuration as described above is not limited to the light emitting device of the present invention as shown in FIG. 1, and may be applied to other light emitting devices of the present invention.

  In this embodiment, a circuit provided in a pixel portion in order to drive a light emitting element in a light emitting device of the present invention will be described. However, the circuit for driving the light emitting device is not limited to that shown in this embodiment.

  As shown in FIG. 5, a circuit for driving each light emitting element is connected to the light emitting element 301. The circuit includes a driving transistor 321 that determines light emission / non-light emission of the light emitting element 301 based on a video signal, a switching transistor 322 that controls input of the video signal, and a light emitting element 301 regardless of the video signal. And an erasing transistor 323 which is brought into a non-light-emitting state. Here, the source (or drain) of the switching transistor 322 is connected to the source signal line 331, and the source of the driving transistor 321 and the source of the erasing transistor 323 are extended in parallel with the source signal line 331. 332, the gate of the switching transistor 322 is connected to the first scanning line 333, and the gate of the erasing transistor 323 extending in parallel with the first scanning line 333 is connected to the second scanning line 334. Yes. Further, the driving transistor 321 and the light emitting element 301 are connected in series.

  A driving method when the light emitting element 301 emits light will be described. When the first scan line 333 is selected in the writing period, the switching transistor 322 whose gate is connected to the first scan line 333 is turned on. Then, when the video signal input to the source signal line 331 is input to the gate of the driving transistor 321 through the switching transistor 322, a current flows from the current supply line 332 to the light emitting element 302, thereby emitting green light. . At this time, the luminance of light emission is determined by the magnitude of the current flowing to the light emitting element 302.

  Note that the light-emitting element 301 corresponds to the light-emitting element 24 in FIG. 1, and the driving transistor 321 corresponds to the transistor 16 in FIG. The erasing transistor 323 corresponds to the transistor 28 in FIG. 2, and the switching transistor 322 corresponds to the transistor 27 in FIG. Further, the source signal line 331 corresponds to the wiring 19c in FIG. 2, the current supply line 332 corresponds to the wiring 19b in FIG. 2, the first scanning line 333 corresponds to the wiring 29a in FIG. A line 334 corresponds to the wiring 29b in FIG.

  In addition, the configuration of the circuit connected to each light emitting element is not limited to that described here, and may be different from the above as illustrated in FIG.

  Next, the circuit shown in FIG. 6 will be described.

  As shown in FIG. 6, the light emitting element 801 is connected to a circuit for driving each light emitting element. The circuit includes a driving transistor 821 that determines light emission / non-light emission of the light emitting element 801 according to a video signal, a switching transistor 822 that controls input of the video signal, and a light emitting element 801 that does not emit light regardless of the video signal. It has an erasing transistor 823 for making a state and a current control transistor 824 for controlling the magnitude of the current supplied to the light emitting element 801. Here, the source (or drain) of the switching transistor 822 is connected to the source signal line 831, and the source of the driving transistor 821 and the source of the erasing transistor 823 extend in parallel with the source signal line 831. 832, the gate of the switching transistor 822 is connected to the first scanning line 833, and the gate of the erasing transistor 823 extending in parallel with the first scanning line 833 is connected to the second scanning line 834. Yes. In addition, a current control transistor 824 is sandwiched between the driving transistor 821 and the light emitting element 801 and connected in series. The gate of the current control transistor 824 is connected to the power supply line 835. Note that the current control transistor 824 is configured and controlled so that a current flows in a saturation region in the voltage-current (Vd-Id) characteristics, and thus, a current value flowing through the current control transistor 824 is large. Can be determined.

  A driving method when the light-emitting element 801 emits light will be described. When the first scan line 833 is selected in the writing period, the switching transistor 822 whose gate is connected to the first scan line 833 is turned on. Then, the video signal input to the source signal line 831 is input to the gate of the driving transistor 821 through the switching transistor 822. Further, current flows from the current supply line 832 to the light-emitting element 801 through the driving transistor 821 and the current control transistor 824 that is turned on in response to a signal from the power supply line 835, and thus light emission is performed. At this time, the magnitude of the current flowing to the light emitting element is determined by the current control transistor 824.

  The light emitting device of the present invention can efficiently extract light emitted from the light emitting layer to the outside of the light emission. For this reason, in the electronic device which mounted this invention, the power consumption which concerns on a display function becomes low. In addition, since there is little change in the emission spectrum depending on the angle at which the emission extraction surface is viewed, an image with good visibility can be obtained in an electronic device in which the present invention is mounted. Hereinafter, an electronic device and the like in which the present invention is mounted will be described.

  The light emitting device of the present invention is mounted on various electronic devices after mounting and sealing the external input terminal.

  In this example, a light-emitting device of the present invention after sealing and an electronic device in which the light-emitting device is mounted will be described with reference to FIGS. However, what is shown in FIGS. 7, 8, and 9 is one example, and the structure of the light emitting device is not limited to this.

  In this example, a light-emitting device of the present invention will be described with reference to FIGS. 8 is a cross-sectional view in FIG.

  In FIG. 7, a pixel portion 502, drive circuit portions 503 and 504, and a connection terminal portion 505 are provided over a first substrate 501 made of glass. The drive circuit portions 503 and 504 are arranged along one end of the pixel portion 502, respectively. The connection terminal portion is provided adjacent to the drive circuit portion 503, and is connected to the drive circuit portions 503 and 504 by wiring. In this embodiment, a glass substrate is used as the first substrate 501, but a quartz substrate, a flexible substrate such as plastic, or the like may be used.

  In the pixel portion 502, a light-emitting element and a circuit element for driving the light-emitting element (each unit constituting a circuit, which is a transistor, a resistor, or the like) are provided. FIG. 8 schematically shows a cross-sectional structure of the first substrate 501. The present invention is applied to the pixel portion 502.

  A substance having water absorbability is fixed to the second substrate 511 provided to face the first substrate 501. As shown in FIG. 8, the region 512 to which a substance having water absorption properties is fixed is provided outside the pixel portion 502 along the end portion of the pixel portion 502. In FIG. 7, the region 512 overlaps with the driver circuit portions 503 and 504. In this embodiment, granular calcium oxide is used as a substance having water absorption. Further, a recess is provided in part of the second substrate 511, and ester acrylate is used as a fixing agent, and calcium oxide is fixed to the recess.

  Note that in this embodiment, a glass substrate is used as the second substrate 511. However, in addition to this, a quartz substrate, a flexible substrate such as plastic, or the like may be used. Moreover, you may use substances with high moisture permeability other than ester acrylate as a fixing agent. In addition to the resin, an inorganic substance such as siloxane may be used as a fixing agent. In this embodiment, the fixing agent is solidified by heating. However, the present invention is not limited to this, and a substance that includes a polymerization initiator and has photocurability and high moisture permeability may be used as a fixing agent. In this embodiment, granular calcium oxide is used as the substance having water absorption, but other substances having water absorption may be used. Alternatively, a composition obtained by injecting into a recess a composition in which molecules capable of adsorbing water by chemical adsorption are mixed in an organic solvent may be used.

  The first substrate 501 and the second substrate 511 are attached to each other with a sealant 522 so that the light-emitting element and the transistor are contained inside. Further, a flexible printed circuit board (FPC) 523 is connected through a connection terminal portion 505.

  Note that a space surrounded by the first substrate 501, the second substrate 511, and the sealant 522 (inside the light-emitting device) is filled with an inert gas such as nitrogen. Note that the interior surrounded by the first substrate 501, the second substrate 511, and the sealant 522 may be filled with a resin material or the like in addition to gas as in this embodiment. In addition, on the surface of the second substrate 511 on the side where a hygroscopic substance is fixed, a layer for preventing moisture from entering may be provided as a single layer or a multilayer.

  In the light-emitting device of the present invention described above, since there is nothing to prevent extraction of light emitted from the pixel portion 502 to the outside, the second electrode of the light-emitting element (provided on the side opposite to the substrate with the light-emitting layer as the center) This is effective when light emission is taken out from the electrode). In addition, since the water-absorbing substance is fixed in the region 512, even if the first substrate 501 and the second substrate 511 are bonded to each other, the substance having the water-absorbing property is driven by the driver circuit portion 503. , 504, and the drive circuit portions 503 and 504 can be prevented from being damaged by the water-absorbing substance.

  FIG. 9 shows an embodiment of an electronic device mounted with a light emitting device to which the present invention is applied.

  FIG. 9A illustrates a laptop personal computer manufactured by applying the present invention, which includes a main body 5521, a housing 5522, a display portion 5523, a keyboard 5524, and the like. A personal computer can be completed by incorporating a light-emitting device having the light-emitting element of the present invention as a display portion.

  FIG. 9B illustrates a cellular phone manufactured by applying the present invention, which includes a main body 5552 which includes a display portion 5551, an audio output portion 5554, an audio input portion 5555, operation switches 5556 and 5557, an antenna 5553, and the like. Has been. A personal computer can be completed by incorporating a light-emitting device having the light-emitting element of the present invention as a display portion.

  FIG. 9C illustrates a television set manufactured by applying the present invention, which includes a display portion 5531, a housing 5532, a speaker 5533, and the like. A television receiver can be completed by incorporating a light-emitting device having the light-emitting element of the present invention as a display portion.

  As described above, the light-emitting device of the present invention is very suitable for use as a display portion of various electronic devices.

  Note that although a laptop personal computer is described in this embodiment, a light-emitting device having the light-emitting element of the present invention may be mounted on a mobile phone, a car navigation system, a lighting device, or the like.

FIG. 14 is a cross-sectional view illustrating a structure of a light-emitting device of the present invention. FIG. 7 is a top view for explaining a structure of a light-emitting device of the present invention. 8A and 8B illustrate a method for manufacturing a light-emitting device of the present invention. 8A and 8B illustrate a method for manufacturing a light-emitting device of the present invention. 3A and 3B each illustrate a circuit for operating a light-emitting device of the present invention. 3A and 3B each illustrate a circuit for operating a light-emitting device of the present invention. The top view explaining the light-emitting device of this invention after sealing. Sectional drawing explaining the light-emitting device of this invention after sealing. 6A and 6B illustrate electronic devices to which the present invention is applied.

Explanation of symbols

11 substrate 12 insulating layer 12a insulating layer 12b insulating layer 13 semiconductor layer 14 gate insulating layer 15 gate electrode 16 transistor 17 insulating layer 17a insulating layer 17b insulating layer 18 insulating layer 19 conductive layer 19a connecting portion 19b wiring 19c wiring 19d film 20 electrode 21 Partition layer 22 Light emitting layer 23 Electrode 24 Light emitting element 28 Transistor 27 Transistor 29a Wiring 29b Wiring 301 Light emitting element 302 Light emitting element 321 Driving transistor 322 Switching transistor 323 Erasing transistor 331 Source signal line 332 Current supply line 333 First scanning line 334 Second scanning line 801 Light emitting element 821 Driving transistor 822 Switching transistor 823 Erasing transistor 824 Current control transistor 831 Source signal line 832 Current supply line 833 First Scan line 834 Second scan line 835 Power supply line 501 Substrate 502 Pixel portion 503 Drive circuit portion 505 Connection terminal portion 511 Substrate 512 Region 522 Sealing material 523 Flexible printed circuit board (FPC)
5521 Main body 5522 Housing 5523 Display unit 5524 Keyboard 5551 Display unit 5552 Main body 5553 Antenna 5554 Audio output unit 5555 Audio input unit 5556 Operation switch 5531 Display unit 5532 Housing 5533 Speaker

Claims (7)

A substrate,
A first insulating layer provided on the substrate;
A transistor provided on the first insulating layer;
A second insulating layer that covers the transistor and has a first opening provided to expose the substrate;
A light-emitting device, wherein a first electrode, a light-emitting layer, and a second electrode are sequentially stacked on the substrate inside the first opening. A substrate,
A first insulating layer provided on the substrate;
A transistor provided on the first insulating layer;
A second insulating layer covering the transistor and having a first opening provided to expose the substrate;
A third insulating layer covering the first opening and the second insulating layer;
A light-emitting device, wherein a first electrode, a light-emitting layer, and a second electrode are sequentially stacked on the substrate inside the first opening.   3. The light emitting device according to claim 2, wherein the third insulating layer is silicon nitride containing oxygen. A substrate,
A first insulating layer provided on the substrate;
A transistor provided on the first insulating layer;
A second insulating layer covering the transistor and having a first opening provided to expose the substrate;
A first electrode covering the first opening;
A partition layer provided with a second opening so that the first electrode is exposed;
A light emitting layer provided on the first electrode exposed in the second opening;
And a second electrode provided on the light emitting layer.   5. The light emitting device according to claim 1, wherein the second insulating layer includes a layer made of silicon nitride containing oxygen. 6.   6. The light-emitting device according to claim 1, wherein the first insulating layer includes a layer made of silicon nitride containing oxygen.   An electronic apparatus using the light-emitting device according to claim 1 for a display portion.

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