Light-emitting device and display apparatus

The present invention has an element (hereinafter, "light emitting device") having a structure in which a thin film that emits light by a phenomenon called electroluminescence (hereinafter, "EL") is sandwiched between an anode, a cathode, and the anode and the cathode. ), And a display device having the light emitting element on the substrate. The present invention also relates to an electronic device having the light emitting element in the image display unit.

The EL display is one of the light emitting devices that is attracting the most attention as a next-generation flat panel display. A light emitting element used in a light emitting device is obtained by installing a thin film made of an organic compound (hereinafter referred to as "organic thin film") between two electrodes and energizing the electrodes to obtain light emission. The electrons injected from the cathode and the holes injected from the anode recombine in the organic thin film to form molecular excitons, and when the molecular excitons return to the ground state, photons are emitted, that is, light emission occurs. .. At this time, one molecule exciton is generated by recombination of one electron and one hole. When these molecular excitons are deactivated to the ground state with light emission, one photon (hereinafter referred to as photon) having a wavelength corresponding to the energy difference between the excited state and the ground state is emitted (this is referred to as a radiation process). Call.).

In a normal organic EL device, an organic thin film is sandwiched between a pair of anodes and cathodes. Therefore, the ratio of the number of holes and electrons injected from the anode and cathode (hereinafter referred to as carriers when holes and electrons are not distinguished) and the number of photons emitted, that is, the quantum efficiency may exceed 1. There is no.

As one of the methods for solving such a limitation, a method of forming a new intermediate conductive layer in the device separately from the cathode and the anode has been proposed (see Patent Document 1).<patcit num="1"><text>Japanese Unexamined Patent Publication No. 11-329748 (pages 6 to 7, Fig. 3)</text></patcit>

In Patent Document 1, Alq: Li layer 13 and In-Zn-O (indium-zinc oxide) composed of Alq (Al complex of 8-hydroxyquinolin) and Li are contained in an element sandwiched between a pair of anode 11 and cathode 12. (Object) An organic EL device has been proposed in which layers 14 are formed and organic layers 15 and 16 are installed on both the anode side and the cathode side of these layers (see FIG. 14). Reference numeral 17 denotes an interlayer insulating film. Here, the layer in which the Alq: Li layer and the In-Zn-O layer are laminated is defined as an intermediate conductive layer. In an organic EL device having such a configuration, holes and electrons are first injected from the anode and the cathode, respectively, as in the case of a normal organic EL device. Holes are transported to the cathode side and electrons are transported to the anode side. What is characteristic here is that carriers are also supplied from the intermediate conductive layer. That is, electrons are injected into the organic layer 15 from the anode side (Alq: Li layer 13 side) of the intermediate conductive layer, and at the same time, holes are injected into the organic layer 16 from the cathode side (In-Zn-O layer 14 side) of the intermediate conductive layer. Is injected into. In the organic layer 15 on the anode side, the holes injected from the anode 11 and the electrons injected from the intermediate conductive layers 13 and 14 are recombined to generate molecular excitons, and light emission can be obtained. Similarly, in the organic layer 16 on the cathode side, electrons injected from the cathode 12 and holes injected from the intermediate conductive layers 13 and 14 are recombined, and light emission is obtained by the radiation process of the generated molecular excitons. ..

By the mechanism described above, this organic EL element can obtain almost the same effect as that of a normal organic EL element arranged in series. That is, although the drive voltage is almost doubled as compared with a normal organic EL device, it is possible to obtain twice the number of photons from the same current density. Therefore, the quantum efficiency is almost doubled. By applying this method, it is possible to further increase the quantum efficiency. For example, if two intermediate conductive layers and three organic thin films are installed alternately, almost the same effect as installing three organic EL elements in series can be obtained. Therefore, the drive voltage is about tripled, but at the same time the quantum efficiency is almost tripled, making it possible to provide a high-brightness organic EL device.

A prerequisite for realizing this concept is that the intermediate conductive layer sandwiched between the organic layers is transparent. In order to meet this requirement, there are restrictions on the materials that can be used for the intermediate conductive layer. Various materials have been proposed so far, but the ones that are actually used consist of 1) electron-transporting compounds such as Alq and bassokproin (BCP) and electron-injecting compounds such as alkali metals. Lamination of mixed layer and transparent electrodes such as ITO (indium tin oxide) and IZO (indium zinc oxide), 2) Lamination of mixed layer composed of the electron-transporting compound and electron-injectable compound and metal oxide, 3) It is limited to a mixed layer composed of the electron transporting compound and the electron injecting compound and a lamination of an electron accepting organic compound.

By using the above-mentioned materials, the intermediate conductive layer can maintain the transparency, but the material restrictions are still very large, and the manufacturing process of the device becomes complicated. For example, to explain by the method of Patent Document 1, first, the organic layer is usually formed by a vacuum vapor deposition method. By this method, a mixed layer of an electron transporting compound and an electron injecting compound can be easily formed on the organic layer. However, transparent electrodes such as ITO and IZO cannot be formed by the vacuum vapor deposition method, and are formed by sputtering. Therefore, after the element is once moved from the film forming chamber for vapor deposition to the film forming chamber for sputtering, these transparent electrodes must be formed, which complicates the manufacturing process.

Further, as a technique related to Patent Document 1, an organic electroluminescence device in which a plurality of light emitting units are partitioned by a layer forming one isopotential surface, as shown in Patent Documents 2 and 3, and Patent Document. An organic EL device having a structure in which a conductive thin film layer is inserted between two organic EL layers shown in 4 is known.<patcit num="2"><text>Japanese Patent Application Laid-Open No. 2003-45676 (Page 1, Fig. 3)</text></patcit><patcit num="3"><text>Japanese Patent Application Laid-Open No. 2003-272860 (1st page, Fig. 8)</text></patcit><patcit num="4"><text>Japanese Patent Application Laid-Open No. 2003-264085 (Page 11, Fig. 7)</text></patcit>

<p>The present invention has been made in view of the above problems, and greatly widens the selection range of materials that can be used as an intermediate conductive layer sandwiched between organic thin films that function as light emitting layers, has high luminous efficiency, and consumes power. An object of the present invention is to provide a light emitting element represented by an organic EL element having a small size and high reliability, and a display device (light emitting device) using the light emitting element.</p>

<p>The light emitting element according to the present invention is a light emitting element formed by at least stacking a first electrode, a first light emitting layer, an intermediate conductive layer, a second light emitting layer, and a second electrode. The intermediate conductive layer includes a layer responsible for electron injection and a layer responsible for hole injection in contact with the layer responsible for electron injection, and at least one of the layer responsible for electron injection and the layer responsible for hole injection is island-shaped. It is characterized by being a layer. Here, the first electrode may have a function of an anode or a function of a cathode. On the other hand, the second electrode may be an anode or a cathode as long as it has the opposite polarity to that of the first electrode. Further, the island-shaped layer responsible for electron injection and the layer responsible for hole injection are also collectively referred to as an intermediate conductive layer, and the layers are appropriately stacked according to the polarities of the first electrode and the second electrode. Can be selected. Further, instead of forming the layer responsible for electron injection into an island shape, the layer responsible for hole injection may be formed into an island shape. In addition, both may be island-shaped. The island-shaped layers referred to here may be island-shaped scattered layers formed, and may be dot-shaped, protrusion-shaped, or a mass (cluster-shaped) in which they are gathered. The shape does not matter. In addition, the state of the arrangement scattered in the island shape may be random or intentional. In any case, of the intermediate conductive layers, the layer responsible for electron injection is in contact with the light emitting layer on the anode side, the layer responsible for hole injection is in contact with the light emitting layer on the cathode side, and electron injection and positive The structure may be such that the layers responsible for hole injection are in contact with each other.</p><p>Further, in the light emitting device according to the above invention, a third light emitting layer is formed on the second light emitting layer via a newly provided intermediate conductive layer (a layer responsible for electron injection and a layer responsible for hole injection). You may. In this case, it is desirable that at least one of the layer responsible for electron injection and the layer responsible for hole injection contained in at least one intermediate conductive layer is island-shaped. That is, when the light emitting layer has a three-layer structure, two intermediate conductive layers are sandwiched, but at least one of the layers responsible for electron injection or the layer responsible for hole injection is island-shaped. Just do it. Further, the number of laminated light emitting layers and intermediate conductive layers is not particularly limited. For example, when four light emitting layers are laminated, three intermediate conductive layers are sandwiched between the light emitting layers. To pinch. Alternatively, when the number of light emitting layers is 5, four intermediate conductive layers are sandwiched between the light emitting layers.</p><p>Specifically, it is a light emitting element formed by stacking a first electrode, a plurality of light emitting layers, a plurality of intermediate conductive layers sandwiched between the plurality of light emitting layers, and a second electrode. The intermediate conductive layer includes a layer responsible for electron injection and a layer responsible for a hole injection layer in contact with the layer responsible for electron injection, and at least one of the layer responsible for electron injection and the layer responsible for the hole injection layer is an island. It is characterized by being a shaped layer.</p><p>More specifically, n light emitting layers from the 1st to the nth (n is an integer of 2 or more) are sequentially laminated between the two electrodes, and the kth (k is 1 k ). An intermediate conductive layer is included between the light emitting layer of (an integer (n-1)) and the k + 1th light emitting layer. Further, the intermediate conductive layer includes a layer responsible for electron injection and a layer responsible for hole injection in contact with the layer responsible for electron injection, and at least one of the layer responsible for electron injection and the layer responsible for hole injection is It is characterized by being an island-shaped layer. Further, the first electrode is a pixel electrode, and the second electrode is a counter electrode.</p><p>Further, the display device according to the present invention has a transistor provided on a substrate and a light emitting element connected to the transistor via an interlayer insulating film, and the light emitting element has a first electrode and a first light emitting element. It is a light emitting element formed by at least stacking a light emitting layer (1), an intermediate conductive layer, a second light emitting layer, and a second electrode, and the intermediate conductive layer is a layer responsible for electron injection and the electron injection. It is characterized in that it includes a layer responsible for hole injection in contact with a layer responsible for electron injection, and at least one of the layer responsible for electron injection and the layer responsible for hole injection is an island-shaped layer. Here, the first electrode in the light emitting element may have a function of an anode or may have a function of a cathode. On the other hand, the second electrode may be an anode or a cathode as long as it has the opposite polarity to that of the first electrode. Further, the island-shaped layer responsible for electron injection and the layer responsible for hole injection are also collectively referred to as an intermediate conductive layer, and the layers are appropriately stacked according to the polarities of the first electrode and the second electrode. Can be selected. Further, instead of forming the layer responsible for electron injection into an island shape, the layer responsible for hole injection may be formed into an island shape. In addition, both may be island-shaped. In any case, of the intermediate conductive layers, the layer responsible for electron injection is in contact with the light emitting layer on the anode side, the layer responsible for hole injection is in contact with the light emitting layer on the cathode side, and electron injection and positive The structure may be such that the layers responsible for hole injection are in contact with each other.</p><p>Further, in the display device according to the above invention, a third light emitting layer is formed on the second light emitting layer via a newly provided intermediate conductive layer (a layer responsible for electron injection and a layer responsible for hole injection). You may. In this case, it is desirable that at least one of the layer responsible for electron injection and the layer responsible for hole injection contained in at least one intermediate conductive layer is island-shaped. That is, when the light emitting layer has a three-layer structure, two intermediate conductive layers are sandwiched, but at least one of the layers responsible for electron injection or the layer responsible for hole injection is island-shaped. Just do it. Further, the number of laminated light emitting layers and intermediate conductive layers is not particularly limited. For example, when four light emitting layers are laminated, three intermediate conductive layers are sandwiched between the light emitting layers. Alternatively, when the number of light emitting layers is 5, four intermediate conductive layers are sandwiched between the light emitting layers.</p><p>Specifically, it has a transistor provided on a substrate and a light emitting element connected to the transistor via an interlayer insulating film, and the light emitting element includes a first electrode, a plurality of light emitting layers, and the light emitting element. It is a light emitting element formed by laminating a plurality of intermediate conductive layers sandwiched between a plurality of light emitting layers and a second electrode, and the intermediate conductive layer is a layer responsible for electron injection and a layer responsible for electron injection. It is characterized in that it includes a layer responsible for a hole injection layer in contact with the electron injection layer, and at least one of the layer responsible for electron injection and the layer responsible for the hole injection layer is an island-shaped layer.</p><p>More specifically, it has a transistor provided on a substrate and a light emitting element connected to the transistor via an interlayer insulating film, and the light emitting element is located between two electrodes from the first to n. N light emitting layers up to the th (n is an electron of 2 or more) are sequentially stacked, and the kth (k is an electron of 1 k (n-1)) and the k + 1th light emitting layer. An intermediate conductive layer is included between the light emitting layer, and the intermediate conductive layer includes a layer responsible for electron injection and a layer responsible for hole injection in contact with the layer responsible for electron injection, and is responsible for the electron injection. At least one of the layer and the layer responsible for hole injection is an island-shaped layer. Further, the first electrode is a pixel electrode, and the second electrode is a counter electrode.</p>

<p>The light emitting element according to the present invention is an EL element having a plurality of light emitting layers between the first electrode and the second electrode, in which an intermediate conductive layer is provided between the light emitting layers and an intermediate conductive layer (a plurality of intermediate layers). When the conductive layer is provided, at least one of the intermediate conductive layers) is characterized in that either of the layers responsible for hole injection or electron injection is formed in an island shape instead of a film shape. To do. By adopting such a structure, the following effects can be obtained.</p><p>First, it is not necessary to consider the transparency of the material in the intermediate conductive layer for injecting electrons (or holes). Even if the intermediate conductive layer has a large absorption coefficient in the visible portion, if it is formed in an island shape, the absorption itself becomes negligibly small. Therefore, the light emitted from the light emitting layer is hardly absorbed by the intermediate conductive layer.</p><p>Further, when an organic material (particularly an aromatic compound) is used as the intermediate conductive layer, the crystallinity of the intermediate conductive layer becomes high unless aggressive molecular design is performed. As a result, the characteristics of the element change drastically, and in the worst case, conduction occurs between both electrodes, resulting in a short circuit. However, when the configuration according to the present invention is adopted, even if the individual island-shaped layers are crystallized, the influence of crystallization on the characteristics of the light emitting device can be reduced or neglected. Changes in the characteristics of the device can be suppressed.</p><p>Further, as a matter of course, the material itself may be used in a small amount, and as a result, the manufacturing time of the device can be shortened, which leads to cost reduction. In this way, various effects can be produced by forming a part of the intermediate conductive layer, which has been conventionally formed in a film shape, in an island shape.</p><p>Further, since the display device according to the present invention includes a light emitting element having the above-mentioned effects, it brings about various effects such as high light extraction efficiency, low power consumption, low cost, and long life.</p>

Embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and its form and details can be variously changed without departing from the gist and scope of the present invention. Therefore, the present invention is not construed as being limited to the description of the embodiments shown below. For example, it is possible to carry out a combination of the embodiments described below and the characteristic parts of each embodiment. In the configuration of the present invention described below, reference numerals indicating the same thing are commonly used among different drawings.

An embodiment of the present invention will be described with reference to FIG. Although FIG. 1 shows an element structure in which two light emitting layers are separated by one intermediate conductive layer, there is no limitation on the number of light emitting layers. Further, due to the structure, the number of intermediate conductive layers is one less than the total number of light emitting layers.

First, in an organic EL element, since it is necessary to extract light emission, at least one of the anode and the cathode needs to be transparent. Hereinafter, a so-called bottom emission type (bottom emission type) light emitting element, which is a light emitting element capable of forming a transparent anode on the substrate side and extracting light emission from the anode side, will be described.

First, a substrate 101 for supporting a light emitting element or the like is prepared. As the substrate 101, not only quartz and glass but also paper and plastic resin can be used. It is also possible to use a substrate on which a thin film transistor (hereinafter referred to as TFT) is mounted in advance. In the embodiment of the present invention, since the transparent anode 102 is formed on the substrate and the light is taken out to the substrate side, it is sufficient that the substrate has visible light transmission. As the transparent anode, a conductive metal oxide such as ITO or IZO is suitable. These conductive metal oxide films are usually formed by sputtering, but may be produced by applying a sol-gel method or the like. Further, as a material other than the metal oxide, it is also possible to use a metal having a large work function such as gold. However, in this case, an ultrathin film is formed in consideration of light transmission.

The first light emitting layer 103 is formed on the anode thus formed. This light emitting layer is formed mainly by using an organic compound, but may be formed by using a thin film having a single composition. For example, Tris (8-quinolinolato) aluminum (abbreviation: Alq)₃), Tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq)₃), Bis (10-Hydroxybenzo [h] -Kinorinato) Beryllium (abbreviation: BeBq)₂), Bis (2-methyl-8-quinolinolato)-(4-phenylphenolato) -aluminum (abbreviation: BAlq), bis [2- (2-hydroxyphenyl) -benzoxazolate] zinc (abbreviation: Zn (abbreviation: Zn) BOX)₂), Bis [2- (2-Hydroxyphenyl) -benzothiazolato] Zinc (abbreviation: Zn (BTZ))₂) And other typical metal complexes. Alternatively, compounds containing hydrocarbons such as 9,10-diphenylanthracene and 4,4'-bis (2,2-diphenylethenyl) biphenyl are also suitable.

Further, the light emitting layer may be a mixed layer of a plurality of materials. Luminous efficiency can be improved by mixing a small amount of a fluorescent material or a phosphorescent material with the above-mentioned light emitter. Examples of the fluorescent material include a coumarin derivative, a quinacridone derivative, an acridone derivative, a pyrene derivative, a perylene derivative, an anthracene derivative, and a pyrone derivative. As a phosphorescent material, as a triplet luminescent material, tris (2-phenylpyridine) iridium (hereinafter, "Ir (ppy)"₃, 2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphyrin-platinum (hereinafter referred to as "PtOEP"), Ir, Ru, Rh, Pt, or Examples include transition metal complexes such as rare earth metals.

On the other hand, the light emitting layer may be a film having a laminated structure. By adopting a laminated structure, it becomes easier to control the injection balance of electrons and holes as compared with the case of using the above-mentioned single composition light emitting layer or mixed light emitting layer, and the luminous efficiency is further improved. Can be planned. For example, in addition to the above-mentioned single composition or mixed composition light emitting layer, a hole transport layer that efficiently transports injected holes to the light emitting layer, and an electron transport layer that efficiently transports injected electrons to the light emitting layer. It is good to provide. In the present specification, in addition to the light emitting layer, a hole transporting layer, an electron transporting layer, or a hole-injecting layer or an electron-injecting layer added may also be referred to as a light emitting layer. Suitable materials for the hole transport layer are compounds containing aromatic amines (ie, those with a benzene ring-nitrogen bond). Widely used materials include 4,4'-bis [N- (3-methylphenyl) -N-phenyl-amino] -biphenyl, a derivative of it, 4,4'-bis [N- (1-naphthyl). )-N-Phenyl-Amino] -Biphenyl, 4,4', 4''-Tris (N, N-diphenyl-Amino) -Triphenylamine, 4,4', 4''-Tris [N- (3) Examples include starburst aromatic amine compounds such as -methylphenyl) -N-phenyl-amino] -triphenylamine. Examples of suitable materials for the electron transport layer include the above-mentioned typical metal complexes, but other materials are 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1. A triazole derivative such as 2,4-triazole, a phenylanthroline derivative such as vasofenantroline or vasocuproin, or a benzoxazole derivative such as bis (5-methylbenzoxazole-2-yl) stilben may be used.

As the film forming method, not only the vacuum vapor deposition method but also a so-called wet method such as a spin coating method, a dip coating method, and a spray method may be adopted.

Next, the intermediate conductive layer is formed. In the present embodiment, since the light emitting element is formed from the anode side, the layer 104 responsible for electron injection is first formed. Here, the layer 104 responsible for electron injection may be formed in an island shape as shown in the figure. In order to form the island shape, it is preferable to form it by, for example, a thin-film deposition method. Specifically, in this case, the vapor deposition process may be stopped after the sublimated material first forms nuclei, and then the nuclei grow and clusters grown from different nuclei bond with each other. Further, as a material suitable for forming the layer 104 responsible for electron injection, first, a metal having a small work function and a metal compound thereof can be mentioned. For example, Mg-Ag alloy, Al-Li alloy, Mg-Li alloy, Ca₃N₂, Mg₃N₂And so on. In addition to metals, organic semiconductors doped with donors can be mentioned. A preferable example of the organic semiconductor referred to here is a compound having an acceptor property, and an electron transporting material often used in a light emitting device may be used. Examples thereof include typical metal complexes typified by Alq, phenanthroline derivatives, triazine derivatives, oxazole derivatives, quinoline derivatives, quinoxalin derivatives and the like. In addition, electron-receptive compounds such as tetracyanoquinodimethane, tetracyanoethylene, and tetrachloroquinone are also good examples. Other examples include condensed aromatic hydrocarbons such as rubrene and perylene derivatives. Further, a conductive material such as graphite can also be used. Further, conjugated polymers such as polyphenylene vinylene, polyphenylene ethane, and polypyridine can also be used. However, in this case, it is preferable to use a polymer for the light emitting layer as well. Further, it is preferable to design so that the polymer used for forming the light emitting layer is not dissolved in the solvent for dissolving the polymer used for forming the intermediate conductive layer. This is because the polymer material is usually formed by a wet method, so that the light emitting layer is dissolved by the solvent that dissolves the polymer material, and the thin film structure is prevented from being destroyed. As a donor to be doped in an organic semiconductor, a metal having a small work function such as an alkali metal or an alkaline earth metal is preferable. Alternatively, an electron-rich organic compound such as tetrathiafulvalene may be used. However, it is essential that the acceptability of organic semiconductors is strong. This is because the donor property of electron-rich organic compounds is smaller than that of alkali metals and alkaline earth metals. Examples other than organic semiconductors include alkali metals, alkaline earth metals, rare earth metals, and compounds containing these. Specific examples thereof include calcium fluoride, lithium oxide, lithium chloride, lithium fluoride, magnesium fluoride and barium oxide.

In this way, the layer 104 responsible for electron injection is formed on the first light emitting layer 103 in the form of a film or an island. The layer 104 responsible for electron injection may be in the shape of a film or an island, but by forming the layer 104 in the shape of an island, the emitted light can be efficiently taken out to the outside. Further, by forming the layer 104 responsible for electron injection in an island shape, even if a substance that is easily crystallized is used, defects of the light emitting element due to crystallization are less likely to occur (see FIG. 1).

Further, in FIG. 2, of the intermediate conductive layers, a layer 104 responsible for electron injection is formed, and then a layer 105 responsible for hole injection is formed. Examples of materials suitable for forming the layer responsible for this hole injection include metals such as gold, aluminum, platinum, copper, and nickel. Since these have a large work function, hole injection becomes easy. These materials cannot maintain transparency unless they are made into ultra-thin films. However, as proposed in the present invention, if the layers responsible for electron injection are formed in a film shape and then the layers responsible for hole injection are formed in an island shape, the intermediate conductive layer itself becomes transparent. The lightness can be maintained.

As another example of the material constituting the layer responsible for hole injection, various metal-containing compounds can be used. Examples thereof include transition metal oxides such as cobalt oxide, titanium oxide, niobium oxide, nickel oxide, neodium oxide, vanadium oxide, beryllium oxide aluminum, molybdenum oxide, lanthanum oxide, ruthenium oxide and renium oxide. Preferably, group 4 to group 7 transition metal oxides, nitrides and halides are used. These metal oxides, nitrides, halides and the like cause an electron transfer reaction at the interface where these materials are in contact with the light emitting layer to form a so-called charge transfer complex, so that holes can be injected by themselves. In addition, these materials may be doped with a suitable donor to positively form a charge transfer complex. Examples of the donor include an electron-excessive organic compound, and examples thereof include tetrathiafulvalene and a carbazole derivative. A good example is aromatic amines that are classified as so-called hole transport and injection materials in organic EL devices. Specific examples include TPD and NPB.

The layer 105 responsible for these hole injections may be in the shape of a film or an island, but by forming the layer 105 in the shape of an island, the emitted light can be efficiently taken out to the outside. Further, by forming the layer 105 responsible for hole injection in an island shape, even if a substance that is easily crystallized is used, defects of the light emitting element due to crystallization are less likely to occur.

If the transparency cannot be maintained unless the layer responsible for electron injection is made into an ultrathin film among the intermediate conductive layers, the layer responsible for electron injection is formed in an island shape and then the hole injection is performed. By forming the layer in the form of a film, the intermediate conductive layer itself can maintain its translucency.

A second light emitting layer 106 is formed on the intermediate conductive layer thus formed. The light emitting layer may have the same structure as the first light emitting layer, or may have a different structure. Further, the emission colors may be the same or different. When the light emission from the first and second light emitting layers is different and they are complementary colors to each other, white light emission is obtained. For example, as shown in FIG. 2A, it may be designed so that blue light is emitted from the first light emitting layer 103 and red light is obtained from the second light emitting layer 106. Specifically, a material whose emission center is observed around 450 to 500 nm, such as an aromatic hydrocarbon compound typified by an anthracene derivative such as 9,10-diphenylanthracene, is used as the first light emitting layer. The second light emitting layer contains a material using so-called DCM such as 4- (dicyanomethylene) -2- [p- (dimethylamino) styryl] -6-methyl-4H-pyran, and aromatic hydrocarbons such as rubrene. A material whose emission center is observed around 600 to 650 nm, such as a hydrogen compound, may be used as the second light emitting layer. Alternatively, as shown in Fig. 2 (b), if three organic thin films (third light emitting layer 108 is added) are prepared and designed to emit the three primary colors of blue, green, and red, respectively, white light emission is also performed. It can also be applied to lighting and the like. As the material responsible for emitting green light, a typical metal complex such as Alq and a fluorescent material such as quinacridone and coumarin are suitable. Or Ir (ppy)₃Phosphorescent materials such as are also available.

A cathode 107 is formed on the second light emitting layer 106 (or the third light emitting layer 108). In this embodiment, since the light emission is taken out from the anode side, the cathode may be non-transparent. Specifically, aluminum, magnesium-silver alloy, or the like may be used. In addition, in order to promote electron injection from the cathode, an electron injection layer may be installed before forming the cathode. As the electron injection layer, an alkali metal salt such as calcium fluoride or lithium fluoride, lithium oxide or lithium chloride, an alkaline earth metal salt or the like may be applied.

In the present embodiment, the anode 102 and the cathode 107 may be interchanged, and in this case, the layers responsible for electron injection and hole injection may also have a reverse laminated structure accordingly.

Further, the number of laminated light emitting layers and intermediate conductive layers is not particularly limited. Specifically, it is a light emitting element formed by stacking a first electrode, a plurality of light emitting layers, a plurality of intermediate conductive layers sandwiched between the plurality of light emitting layers, and a second electrode. The intermediate conductive layer includes a layer responsible for electron injection and a layer responsible for a hole injection layer in contact with the layer responsible for electron injection, and at least one of the layer responsible for electron injection and the layer responsible for the hole injection layer is an island. It is characterized by being a shaped layer. For example, as shown in FIG. 16, n light emitting layers from the first light emitting layer 203 to the nth light emitting layer 213 (n is an integer of 2 or more) are sequentially laminated between the anode 102 and the cathode 107. To do. Then, from the layer 204 responsible for the first electron injection and the layer 205 responsible for the first hole injection into those light emitting layers, the layers 211 and the n-1th holes responsible for the n-1st electron injection are injected. The layer 212 that bears the above is sandwiched. That is, an intermediate conductive layer is included between the k-th (k is an integer such that 1 k (n-1)) light emitting layer 207 and the k + 1th light emitting layer 210, and the intermediate conductive layer is included. Includes a layer 208 responsible for the k-th electron injection and a layer 209 responsible for the k-th hole injection in contact with the k-th electron injection layer 208, and in the present embodiment, the k-th hole. The layer 209 responsible for injection is an island-shaped layer.

In this embodiment, the configuration of an active matrix type display device (also referred to as an active matrix type light emitting device; the same applies hereinafter) using the light emitting element according to the embodiment will be described with reference to FIGS. 3 and 4. The display device according to this embodiment has a plurality of display devices in a region where the source line Sx (x is a natural number, 1 x m) and the gate line Gy (y is a natural number, 1 y n) intersect with each other via an insulator. It has a plurality of pixels 310 including the element of (FIG. 3 (A)). The pixel 310 includes a light emitting element 313, a capacitive element 316, and two transistors. Of the two transistors, one is a switching transistor 311 that controls the input of a video signal to the pixel 310, and the other is a driving transistor 312 that controls the lighting and non-lighting of the light emitting element 313. The capacitive element 316 has a function of holding the gate-source voltage of the transistor 312.

The gate electrode of the transistor 311 is connected to the gate wire Gy, one of the source electrode and the drain electrode is connected to the source wire Sx, and the other is connected to the gate electrode of the transistor 312. One of the source electrode and the drain electrode of the transistor 312 is connected to the first power supply 317 via the power supply line Vx (x is a natural number, 1 x l), and the other is connected to the pixel electrode of the light emitting element 313. The counter electrode (cathode 107) of the light emitting element 313 is connected to the second power source 318. The capacitive element 316 is provided between the gate electrode and the source electrode of the transistor 312. The conductive type of the transistors 311 and 312 may be either N type or P type, but in the configuration shown, the case where the transistor 311 is N type and the transistor 312 is P type is shown. The potential of the first power supply 317 and the potential of the second power supply 318 are not particularly limited, but are set to different potentials so that a forward bias or reverse bias voltage is applied to the light emitting element 313.

The semiconductor constituting the transistors 311, 312 may be any of an amorphous semiconductor (amorphous silicon), a microcrystalline semiconductor, a crystalline semiconductor, an organic semiconductor and the like. Microcrystalline semiconductor is silane gas (SiH)₄) And fluorine gas (F)₂), It may be formed by using silane gas and hydrogen gas, or it may be formed by irradiating a laser beam after forming a thin film using the gases listed above. The gate electrodes of the transistors 311 and 312 are formed of a conductive material in a single layer or in a laminated manner. For example, a laminated structure in which tungsten (W) is stacked on tungsten nitride (WN), a laminated structure in which aluminum (Al) and Mo are stacked on molybdenum (Mo), and Mo is stacked on molybdenum nitride (MoN) in order. A laminated structure may be adopted.

Further, FIG. 3B is a top view of the display panel portion of the display device according to the present embodiment. In FIG. 3B, a light emitting region 400 (also referred to as a pixel region or a display region; the same applies hereinafter) having a plurality of pixels (pixels 310 shown in FIG. 3A) including a light emitting element on the substrate 405. A connection film 407 such as a gate driver 401, a gate driver 402, a source driver 403, and an FPC is provided. The connection film 407 is connected to an IC chip or the like.

4 (A) and 4 (B) show a cross-sectional view taken along the line AB of the display panel of FIG. 3 (B). FIG. 4 (A) shows a dual light emitting element according to the present invention that extracts light from both the upper and lower surfaces of the light emitting layer when the light emitting element according to the present invention is applied to a top emission (top emission) type light emitting device. The light emitting region 400 when applied to an emission (double-sided light emitting) type light emitting device is shown.

First, the configuration shown in FIG. 4 (A) will be described. FIG. 4A shows a transistor 312 provided in the light emitting region 400 (transistor 311 in FIG. 3A is omitted), a light emitting element 313, and an element group 410 provided in the source driver 403. ing. Further, 316 is a capacitive element. A sealing material 408 is provided around the light emitting region 400, the gate drivers 401, 402, and the source driver 403, and the light emitting element 313 is sealed by the sealing material 408 and the facing substrate 406. This sealing process is a process for protecting the light emitting element 313 from moisture. Here, a method of sealing with a cover material (glass, ceramics, plastic, metal, etc.) is used, but a thermosetting resin or ultraviolet light is used. A method of sealing with a curable resin or a method of sealing with a thin film having a high barrier ability such as a metal oxide or a nitride may be used.

Here, as the sealing material 408, a UV-curable or thermosetting epoxy resin may be typically used. Here, the refractive index is 1.50, the viscosity is 500 cps, the shore D hardness is 90, the tencil strength is 3000 psi, the Tg point is 150 ° C, and the volume resistance is 1 × 10.¹⁵Uses a highly heat-resistant UV epoxy resin (manufactured by Electrolite: 2500 Clear) with a withstand voltage of 450 V / mil and Ω · cm.

Further, among the light emitting elements 313, the cathode 107 is connected to the second power supply 318 in FIG. 3 (A). The element formed on the substrate 405 is preferably formed of a crystalline semiconductor (polysilicon) having better properties such as mobility than an amorphous semiconductor, so that monolithicization on the same surface can be achieved. It will be realized. Since the number of external ICs to be connected to the panel having the above configuration is reduced, the panel can be made compact, lightweight, and thin.

The light emitting region 400 may be composed of a transistor having an amorphous semiconductor (amorphous silicon) formed on the insulating surface as a channel portion, and the gate drivers 401 and 402 and the source driver 403 may be composed of an IC chip. The IC chip may be attached on the substrate 405 by the COG method, or may be attached to the connection film 407 connected to the substrate 405. By using the CVD method, the amorphous semiconductor can be easily formed on a large-area substrate and does not require a crystallization step, so that an inexpensive panel can be provided. Further, at this time, if the conductive layer is formed by the droplet ejection method represented by the inkjet method, it is possible to provide a cheaper panel.

Further, in the configuration shown in FIG. 4A, a first interlayer insulating film 411 and a second interlayer insulating film 412 are provided on the transistor 312 and the element group 410. Then, the wiring 414 is formed through the openings provided in the first interlayer insulating film 411 and the second interlayer insulating film 412. The wiring 414 functions as a source wiring or a drain wiring of the transistor 312 and the element group 410. As the wiring 414, it is desirable to use an alloy containing aluminum and nickel. Further, this alloy may further contain carbon, cobalt, iron, silicon and the like. The content thereof is preferably, for example, 0.1 to 3.0 atomic% for carbon, 0.5 to 7.0 atomic% for at least one element among nickel, cobalt, and iron, and 0.5 to 2.0 atomic% for silicon. One of the features of this material is that it has a low resistance value of 3.0 to 5.0 Ωcm.

Here, when Al is used as the wiring 414, there is a problem that corrosion with the anode 102, for example, ITO occurs. However, even in such a case, good contact with ITO can be obtained by forming a laminated structure in which Al (or Al-Si alloy) is sandwiched between Ti or TiN. For example, a laminated structure may be adopted in which Al and Ti are laminated in this order on Ti. On the other hand, the above-mentioned Al-C alloy or Al-C-Ni alloy or the like has an oxidation-reduction potential very similar to that of a transparent conductive film such as ITO, so that it does not have to have a laminated structure (Ti or TiN, etc.). It is possible to make direct contact with ITO etc. (without having to pinch it with). The wiring 414 can be formed by using a target material made of the above alloy and using a sputtering method. Further, when etching the alloy using a resist as a mask, it is preferable to perform wet etching. In this case, phosphoric acid or the like can be used as the etchant. The wiring connected to the second power supply 318 can also be formed in the same manner as the wiring 414.

Further, the anode 102 is formed in contact with the wiring 414. The stacking order of the wiring 414 and the anode 102 does not matter. Since FIG. 4 (A) is a top emission type, a reflective conductive film is used for the anode 102. For example, an element selected from Cr, Ti, TiN, TiSixNy, Ni, W, WSix, WNx, WSixNy, NbN, Pt, Zn, Sn, In or Mo, or an alloy material or compound material containing the element as a main component. A film containing the above as a main component or a laminated film thereof may be used.

Further, in FIG. 4A, the anode 102 extends to the region where the capacitive element 316 is formed, and the anode 102 also plays the role of the capacitive electrode of the capacitive element 316. Of course, a wiring that functions as a capacitive electrode (usually formed at the same time as the wiring 414) may be formed separately.

The material of the first and second interlayer insulating films is not particularly limited. For example, the first interlayer insulating film may be an inorganic material and the second interlayer insulating film may be an organic material. At this time, as the inorganic material, a carbon-containing film such as silicon oxide, silicon nitride, silicon oxynitride, DLC or carbon nitride (CN), PSG (phosphorus glass), BPSG (phosphorus glass), alumina film or the like is used. be able to. As a forming method, a plasma CVD method, a reduced pressure CVD (LPCVD) method, an atmospheric pressure plasma, or the like can be used. Alternatively, an SOG film obtained by a coating method (for example, a SiOx film containing an alkyl group) can also be used. In this embodiment, the first interlayer insulating film 411 provided on the transistor 312 is mainly Na, O.₂Since it has a barrier function to prevent impurities such as moisture from entering the transistor 312 (it is sometimes called a "cap insulating film" because it has this function), it is desirable to form it as much as possible, but it is omitted. It is also possible.

On the other hand, as the organic material, a photosensitive or non-photosensitive organic material such as polyimide, acrylic, polyamide, resist material or benzocyclobutene, or a heat-resistant organic resin such as siloxane can be used. The interlayer insulating film can be formed by spin coating, dipping, spray coating, droplet ejection method (inkjet method, screen printing, offset printing, etc.), doctor knife, roll coater, curtain coater, knife coater, depending on the material. Etc. can be adopted. The above materials may be laminated to form the first and second interlayer insulating films.

A partition wall layer 409 (also called a bank, a bank, a barrier, etc.) is formed around the anode 102. The partition layer 409 includes an organic resin material such as photosensitive or non-photosensitive polyimide, acrylic, polyamide, polyimide amide, resist material or benzocyclobutene), a heat-resistant organic resin such as siloxane, and other inorganic insulating materials (SiN). , SiO, SiON, SiNO, etc.), or a laminate thereof. Here, a photosensitive organic resin covered with a silicon nitride film is used. Further, as the insulator, either a negative type that becomes insoluble in the etchant by photosensitive light or a positive type that becomes soluble in the etchant by light can be used.

The side surface shape of the partition wall layer 409 is not particularly limited, but as shown in FIG. 4 and the like, it is preferable that the partition wall layer 409 has an S shape. In other words, it is desirable to have a structure having an inflection point on the side surface of the partition wall layer 409. As a result, the first light emitting layer 103 formed on the first electrode (anode 102), the intermediate conductive layer (that is, the layer 104 responsible for electron injection and the layer 105 responsible for hole injection), and the second light emitting layer. The coverage of 106, cathode 107, etc. can be improved. However, the structure is not limited to this, and a structure in which a curved surface having a radius of curvature is provided only at the upper end of the insulator may be used.

Further, on the anode 102, the first light emitting layer 103, the intermediate conductive layer (that is, the layer 104 responsible for electron injection and the layer 105 responsible for hole injection), and the second light emitting layer, as in the above embodiment, 106, cathode 107, etc. are formed. On the cathode, a passivation film for blocking impurities such as moisture and oxygen to the light emitting layer, a layer for relaxing the stress of the passivation film, and a low refractive index layer having a small difference in refractive index from air. Etc. may be formed.

Further, since the light emitting device according to the present invention is a top-emission type that emits light by passing through the cathode 107, it is preferable to use an aluminum film of 1 nm to 10 nm or an aluminum film containing a small amount of Li as the cathode 107. When the Al film is used as the cathode 107, the material in contact with the second light emitting layer 106 can be formed of a material other than the oxide, and the reliability of the light emitting device can be improved. In addition, CaF is used as a cathode buffer layer before forming an aluminum film of 1 nm to 10 nm.₂, MgF₂, Or BaF₂A translucent layer (thickness: 1 nm to 5 nm) may be formed. In addition, in order to reduce the resistance of the cathode 107, a metal thin film of 1 nm to 10 nm and a transparent conductive film (ITO, indium tin oxide alloy (In))₂O₃-It may be a laminated structure with (ZnO), zinc oxide (ZnO), etc.). Alternatively, in order to reduce the resistance of the cathode, an auxiliary electrode may be provided on the cathode 107 in a region that does not become a light emitting region. Further, when forming the cathode, a resistance heating method by vapor deposition may be used, and the cathode may be selectively formed by using a vapor deposition mask.

In the structure shown in FIG. 4 (A), the wiring 414 is formed through the opening provided in the second interlayer insulating film 412 and is connected to the anode 102, but the second interlayer insulating film 412 A third interlayer insulating film and an anode 102 may be further provided above, and the wiring 414 and the anode 102 may be connected via an opening provided in the third interlayer insulating film. The third interlayer insulating film may be formed in the same manner as the second interlayer insulating film. With such a configuration, the region in which the light emitting element 313 is formed is not limited by the region in which the transistor 312 and the wiring 414 are formed, and the degree of freedom in design is further increased. It also makes it even easier to obtain a display device with the desired aperture ratio.

The position where the connection film 407 is provided is not limited to that shown in FIG. 4A, and may be formed, for example, on the second interlayer insulating film 412 so as to be directly connected to the wiring 414. Further, the space 418 may be filled with a resin or the like.

Next, the configuration shown in FIG. 4B will be described. FIG. 4B shows a cross-sectional view of a light emitting region 400 when the light emitting element according to the present invention is applied to a dual emission type light emitting device. In FIG. 4B, light emitting elements 313 corresponding to R, G, and B are provided. The light emitting layers corresponding to R, G, and B can be produced in the manner of the above-described embodiment.

Further, since the light emitting device according to FIG. 4B is a dual emission type (double-sided emission type), both the anode 102 and the cathode 107 need to have translucency. Therefore, ITO is typically used as the anode 102, but ITSO containing silicon oxide in ITO, zinc oxide (ZnO: Zinc Oxide), zinc oxide (GZO) containing gallium, and indium oxide are also used. A transparent conductive film such as Indium Zinc Oxide (IZO), which is a mixture of 1 to 20% zinc oxide, can also be used.

On the other hand, as the cathode 107, a translucent conductive film formed by a co-evaporation method of Al, AlLi, MgAg, MgIn, Ca, or an element belonging to Group 1 or Group 2 of the periodic table and aluminum can be used. These materials have a small work function and are easy to extract electrons, so they are suitable as cathode materials. However, in order to ensure light transmission, it is necessary to make it an ultra-thin film. A transparent conductive film such as ITO can be used as the cathode 107, but since it does not function as a cathode as it is, a thin film such as Li, which is a material for the cathode, should be formed between the ITO and the second light emitting layer 106. Just do it.

On the anode 102, the first light emitting layer 103, the intermediate conductive layer (that is, the layer 104 responsible for electron injection and the layer 105 responsible for hole injection), the second light emitting layer 106, as in the above embodiment, The cathode 107 and the like are formed. On the cathode, a passivation film for blocking impurities such as moisture and oxygen to the light emitting layer, a layer for relaxing the stress of the passivation film, and a low refractive index layer having a small difference in refractive index from air. Etc. may be formed.

Further, in the invention according to FIG. 4B, carbon or metal particles were added to an organic material such as acrylic, polyimide, or siloxane as all or part of the second interlayer insulating film and partition wall layer. It has a configuration using an interlayer insulating film 417 having a light-shielding property and a partition layer 416 having a light-shielding property. The interlayer insulating film 417 having a light-shielding property is provided with an opening for passing light from the light emitting layer, and the opening is filled with a translucent resin 415 such as acrylic, polyimide, or siloxane. Has been done.

Here, the interlayer insulating film 417 having a light-shielding property and the partition wall layer 416 having a light-shielding property are made of organic materials such as acrylic, polyimide, and siloxane using a shaker, an ultrasonic vibrator, or the like, and have carbon or light-shielding properties. After adding and stirring the metal particles having a siloxane, filtration is performed if necessary, and then the metal particles are formed by a spin coating method. When adding carbon particles or metal particles to an organic material, a surfactant, a dispersant, or the like may be added so as to be uniformly mixed. When adding carbon particles, it is advisable to adjust the amount of carbon particles added so that the concentration of the carbon particles is 5 to 15% by weight. Further, the thin film formed by the spin coating method may be used as it is, or may be fired for the purpose of curing. The transmittance and reflectance of the formed thin film are both 0% or almost 0%.

The material and configuration of the first interlayer insulating film 411, wiring 414, etc. conform to the configuration of the invention according to FIG. 4 (A). Further, a third interlayer insulating film may be separately formed on the second interlayer insulating film, and all or part of the third interlayer insulating film may be used as a light-shielding interlayer insulating film.

The dual-emission type display device shown in FIG. 4B is provided with an interlayer insulating film 417 having a light-shielding property and a partition wall layer 416 having a light-shielding property, so that unnecessary light from the light emitting layer (light emitted from the bottom surface) is provided. (Including the light generated by the reflection of the light), it is possible to suppress the influence of blurring the contour between pixels. That is, since the insulating film having a light-shielding property absorbs unnecessary light, the contour between the pixels becomes clear and a high-definition image can be displayed. Further, since the influence of unnecessary light can be suppressed by arranging the light-shielding film, a polarizing plate becomes unnecessary, and miniaturization, weight reduction, and thinning can be realized. Further, it is possible to prevent unnecessary light from leaking to the transistor forming region of the pixel, and it is possible to drive the active matrix by a highly reliable transistor.

In addition, in FIGS. 4 (A) and 4 (B), when the light emitted from the light emitting element 313 is made white, as shown in the above-described embodiment, R, G, and B are applied to each pixel portion of the display device. A full-color display device can be obtained by providing the color filter of. The color filter can be produced by a known material and a known method. Further, in the case of the dual emission type, the opening provided in the second interlayer insulating film 412 (or the interlayer insulating film 417 having a light-shielding property) contains red, green, and blue pigments and is translucent. A lower color filter (or a film having a color filter function) is formed by filling the resin having the above. It is desirable that the resin containing this pigment is selectively formed by using a droplet ejection method. Further, on the facing substrate side, an upper color filter corresponding to the lower color filter is formed by a known material and method (not shown).

Usually, when a color filter is formed, a black matrix (a grid-like or striped light-shielding film for optically separating R, G, and B pixels) is provided around the color filter. However, in the invention according to the configuration of FIG. 4B described above, instead of using the black matrix, a partition wall layer 416 having a light-shielding property or an interlayer insulating film 417 having a light-shielding property is formed at a position where light shielding is desired. .. Therefore, as compared with forming the black matrix separately, the present invention improves the yield by facilitating alignment and leads to cost reduction because it is not necessary to add an extra step.

In this embodiment, if at least one of the light-shielding partition wall layer 416 and the light-shielding interlayer insulating film 417 is formed, the above-mentioned effects such as suppressing adverse effects due to unnecessary light from the light emitting layer can be suppressed. Can be demonstrated. Of course, it goes without saying that it is desirable that both are formed. In addition, the characteristic parts of the inventions according to FIGS. 4 (A) and 4 (B) can be replaced or combined with each other.

In this embodiment, the anode 102 and the cathode 107 may be interchanged. In this case, the polarity of the transistor 312 connected to the cathode 107 may be changed. In addition, this embodiment can be freely combined with the above-described embodiment and other embodiments.

In this embodiment, an example of a pixel circuit applicable to the present invention other than the pixel circuit shown in FIG. 3A will be described with reference to FIG. FIG. 5 (A) is a pixel circuit having a configuration in which a transistor 340 for erasing and a gate wire Ry for erasing are newly provided in the pixel 310 shown in FIG. 3 (A). By arranging the transistor 340, it is possible to forcibly create a state in which no current flows through the light emitting element 313. Therefore, the lighting period can be set at the same time as or immediately after the start of the writing period without waiting for the signal to be written to all the pixels 310. You can start. Therefore, the duty ratio is improved, and the moving image can be displayed particularly well.

In FIG. 5 (B), the transistor 312 of the pixel 310 shown in FIG. 3 (A) is deleted, and transistors 341 and 342 and a power supply line Vax (x is a natural number, 1 x l) are newly provided. It is a pixel circuit. The power line Vax connects to power 343. In this configuration, by connecting the gate electrode of the transistor 341 to the power supply line Vax held at a constant potential, the potential of the gate electrode of the transistor 341 is fixed and the transistor 341 is operated in the saturation region. Further, the transistor 342 is operated in the linear region, and a video signal including information on whether the pixel is lit or not lit is input to the gate electrode thereof. Since the value of the source-drain voltage of the transistor 342 operating in the linear region is small, a slight fluctuation of the gate-source voltage of the transistor 342 does not affect the current value flowing through the light emitting element 313. Therefore, the current value flowing through the light emitting element 313 is determined by the transistor 341 operating in the saturation region. The present invention having the above configuration can improve the image quality by improving the brightness unevenness of the light emitting element 313 due to the variation in the characteristics of the transistor 341. This embodiment can be freely combined with the above-described embodiment and other embodiments.

In this embodiment, the laminated structure of the wiring 414 (including the second power supply 318; the same shall apply hereinafter in this embodiment) and the pixel electrode (anode or cathode) in the above embodiment will be described with reference to FIG. Each figure of FIG. 6 shows only a part of the light emitting element in the pixel region extracted, and the illustration of the second light emitting layer, the intermediate conductive layer, etc. is omitted.

FIG. 6A shows a case where Mo600 is used as wiring and alloy 601 containing aluminum is laminated, and ITO602 is used as a pixel electrode (for example, anode 102; the same applies hereinafter in this embodiment). As the alloy 601 containing aluminum, it is desirable that aluminum contains carbon, nickel, cobalt, iron, silicon and the like. The content thereof is preferably, for example, 0.1 to 3.0 atomic% for carbon, 0.5 to 7.0 atomic% for at least one element among nickel, cobalt, and iron, and 0.5 to 2.0 atomic% for silicon. One of the features of this material is that it has a low resistance value of 3.0 to 5.0 Ωcm. Here, Mo600 functions as a barrier metal.

In this way, when the alloy 601 containing aluminum contains 0.5% or more of at least one element of nickel, cobalt, and iron, the electrode potential of ITO602 can be approached, and direct contact with ITO602 is possible. become. In addition, the heat resistance of the alloy 601 containing aluminum is also improved. Further, by setting the carbon content to 0.1% or more, the generation of hillock can be suppressed. Further, even when silicon is contained, there is an advantage that hillock is less likely to occur even when heat-treated at a high temperature.

FIG. 6B shows a case where an alloy 603 containing aluminum is used as the wiring and ITO 602 is used as the pixel electrode. Here, the alloy 603 containing aluminum is configured to contain at least nickel. After forming the alloy 603 containing aluminum, nickel contained in the alloy exudes and chemically reacts with Si of the silicon semiconductor layer 608 of the active element (for example, TFT) for driving the pixel region. , Nickel silicide 607 is formed, and there is an advantage that the bondability is improved.

FIG. 6C shows a case where alloy 604 containing aluminum is laminated as wiring and ITO605 is laminated as pixel electrodes. In particular, it was experimentally found that the flatness was remarkably improved when the laminated structure of the combination of both was adopted. For example, the flatness is about the same as the case of the laminated structure of the wiring with TiN formed on the Al-Si alloy and ITO, and the laminated structure of the wiring with TiN formed on the Al-Si alloy and ITSO. It was twice as good.

FIG. 6D shows the case where alloys 604 and 606 containing aluminum are used both as wiring and as pixel electrodes.

Since the above alloy containing aluminum can be easily patterned by wet etching, its application can be widely used regardless of wiring or pixel electrode. However, since the alloy containing aluminum is excellent in reflectivity, it is suitable for a top emission type. Further, in the case of a bottom emission or dual emission type display device, it is necessary to form the wiring or the pixel electrode as a thin film so that light can be transmitted. In addition, this embodiment can be freely combined with the above-described embodiment and other embodiments.

As an electronic device using a display device including a pixel region including a light emitting element according to the present invention, a television device (television, television receiver), a digital camera, a digital video camera, a mobile phone device (mobile phone), a PDA Examples thereof include portable information terminals such as mobile information terminals, portable game machines, monitors, computers, sound reproduction devices such as car audio, and image reproduction devices provided with recording media such as home-use game machines. A specific example thereof will be described with reference to FIG. 7.

The portable information terminal using the display device of the present invention shown in FIG. 7A includes a main body 9201, a display unit 9202, and the like, and can display a high-definition image according to the present invention. The digital video camera using the display device of the present invention shown in FIG. 7B includes display units 9701, 9702 and the like, and can display a high-definition image according to the present invention. A mobile terminal using the display device of the present invention shown in FIG. 7 (C) includes a main body 9101, a display unit 9102, and the like, and can display a high-definition image according to the present invention. The portable television device using the display device of the present invention shown in FIG. 7 (D) includes a main body 9301, a display unit 9302, and the like, and can display a high-definition image according to the present invention. A portable computer using the display device of the present invention shown in FIG. 7 (E) includes a main body 9401, a display unit 9402, and the like, and can display a high-definition image according to the present invention. A television device using the display device of the present invention shown in FIG. 7 (F) includes a main body 9501, a display unit 9502, and the like, and can display a high-definition image according to the present invention. Further, when an interlayer insulating film having a light-shielding property or a partition wall layer having a light-shielding property is provided as in the above embodiment, the influence of unnecessary light can be suppressed, so that a polarizing plate becomes unnecessary and the size is small. It is possible to reduce the weight, weight, and thickness.

Here, the main configuration of the television apparatus will be briefly described with reference to the block diagram of FIG. In the figure, the EL display panel 701 is manufactured by using the display device according to the present invention, and further, as a method of connecting the EL display panel 701 and an external circuit, (1) the pixel portion of the display panel and the scanning line side drive When the circuit 703 is integrally formed on the substrate and the signal line side drive circuit 702 is mounted separately as a driver IC, (2) only the pixel portion of the display panel is formed to form the scanning line side drive circuit 703 and the signal line side drive. There are cases where the circuit 702 is mounted by the TAB method, (3) the scanning line side drive circuit 703 and the signal line side drive circuit 702 are mounted by the COG method in and around the pixel portion of the display panel. However, it may be in any form.

As other external circuit configurations, on the video signal input side, of the signals received by the tuner 704, the video wave amplifier circuit 705 that amplifies the video signal and the signals output from it are in red, green, and blue colors. It consists of a video signal processing circuit 706 that converts the video signal into a color signal corresponding to the above, and a control circuit 707 that converts the video signal into the input specifications of the driver IC. The control circuit 707 outputs signals to the scanning line side and the signal line side, respectively. In the case of digital driving, a signal dividing circuit 708 may be provided on the signal line side, and the input digital signal may be divided into m pieces and supplied.

Of the signals received by the tuner 704, the audio signal is sent to the audio wave amplifier circuit 709, and its output is supplied to the speaker 713 via the audio signal processing circuit 710. The control circuit 711 receives control information of the receiving station (reception frequency) and volume from the input unit 712, and sends a signal to the tuner 704 and the audio signal processing circuit 710.

By incorporating such an external circuit and an EL display panel into the housing, a television receiver as shown in FIG. 7 (F) can be completed. Of course, the present invention is not limited to television receivers, and is applied to various applications such as personal computer monitors, information display boards at railway stations and airports, and advertisement display boards on the streets. can do. In addition, this embodiment can be freely combined with the above-described embodiment or other embodiments.

The display device according to the present invention can be used as an ID card capable of transmitting and receiving data in a non-contact manner by mounting a functional circuit such as a memory or a processing circuit or an antenna coil. An example of the configuration of such an ID card will be described with reference to the drawings.

FIG. 9A shows a form of an ID card having a built-in display device according to the present invention. The ID card shown in FIG. 9 (A) is a non-contact type that transmits / receives data to / from the reader / writer of the terminal device in a non-contact manner. Reference numeral 801 is a card body, and 802 corresponds to a pixel portion of a display device mounted on the card body 801.

FIG. 9B shows the configuration of the card substrate 803 included in the card body 801 shown in FIG. 9A. An ID chip 804 formed of a thin semiconductor film and a display device 805 according to the above embodiment or embodiment are bonded to the card substrate 803. Both the ID chip 804 and the display device 805 are formed on a separately prepared substrate and then transferred onto the card substrate 803. As a transfer method, there are a method of producing a thin film integrated circuit composed of a large number of TFTs and then pasting it using a small vacuum tweezers or the like, or a method of selectively pasting it using a UV light irradiation method. Further, the same can be performed for the pixel unit and the drive circuit unit in the display device. A portion formed by using a thin film semiconductor film including an ID chip 804 and a display device 805 and transferred to a card substrate after formation is referred to as a thin film portion 807.

Further, an integrated circuit 806 manufactured by using a TFT is mounted on the card substrate 803. The method of mounting the integrated circuit 806 is not particularly limited, and a known COG method, wire bonding method, TAB method, or the like can be used. The integrated circuit 806 is electrically connected to the thin film portion 807 via the wiring 808 formed on the card substrate 803.

An antenna coil 809 electrically connected to the integrated circuit 806 is formed on the card substrate 803. Since the antenna coil 809 can send and receive data to and from the terminal device in a non-contact manner using electromagnetic induction, the non-contact type ID card is physically worn compared to the contact type. Less susceptible to damage. Furthermore, the contactless ID card can also be used as a tag (wireless tag) for managing information in a contactless manner. The amount of information that can be managed by a contactless ID card is dramatically higher than that of a barcode that can read information in a contactless manner. Further, the distance between the terminal device and the terminal device capable of reading the information can be made longer than when the bar code is used.

Although FIG. 9B shows an example in which the antenna coil 809 is formed on the card substrate 803, a separately prepared antenna coil may be mounted on the card substrate 803. For example, a coil made by winding a copper wire or the like and pressing the copper wire between two plastic films having a thickness of about 100 μm can be used as an antenna coil. Further, the antenna coil may be built in the thin film integrated circuit. Further, in FIG. 9B, only one antenna coil 809 is used for one ID card, but a plurality of antenna coils 809 may be used.

Although FIG. 9 shows the form of the ID card equipped with the display device 805, the present invention is not limited to this configuration, and it is not always necessary to provide the display device. However, by providing the display device, the data of the facial photograph can be displayed on the display device, and it is possible to make it more difficult to replace the facial photograph as compared with the case where the printing method is used. In addition, information other than the face photo can be displayed, and the functionality of the ID card can be enhanced.

As the card substrate 803, a flexible plastic substrate can be used. As the plastic substrate, ARTON: JSR made of norbornene resin having a polar group can be used. In addition, polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polycarbonate (PC), nylon, polyetheretherketone (PEEK), polysulfone (PSF), polyetherimide (PEI), poly Plastic substrates such as allylate (PAR), polybutylene terephthalate (PBT), and polyimide can be used.

In this embodiment, the electrical connection between the ID chip and the thin film integrated circuit is not limited to the form shown in FIG. For example, the terminals of the ID chip and the terminals of the thin film integrated circuit may be directly connected with an anisotropic conductive resin, solder, or the like, instead of via the wiring formed on the card substrate. Further, in FIG. 9, the connection between the thin film integrated circuit and the wiring formed on the card substrate may be made by a wire bonding method, a flip chip method using a solder ball, or anisotropic conductivity. It may be directly connected with resin or solder, or it may be connected by other methods. Further, the display device according to the present invention can be used by being incorporated not only in an ID card but also in a semiconductor device such as an ID tag, a wireless chip, or a wireless tag.

The light emitting element of the present invention described above can be applied to a pixel portion of a light emitting device having a display function or an illumination unit of a light emitting device having a lighting function. In this embodiment, the circuit configuration and the driving method of the light emitting device having the display function will be described with reference to FIGS. 10 to 13.

FIG. 10 is a schematic view of a light emitting device to which the present invention is applied as viewed from above. In FIG. 10, a pixel unit 6511, a source signal line drive circuit 6512, a write gate signal line drive circuit 6513, and an erasure gate signal line drive circuit 6514 are provided on the substrate 6500. The source signal line drive circuit 6512, the write gate signal line drive circuit 6513, and the erase gate signal line drive circuit 6514 are each connected to an external input terminal FPC (flexible printed circuit) 6503 via a wiring group. Is connected to. Then, the source signal line drive circuit 6512, the write gate signal line drive circuit 6513, and the erase gate signal line drive circuit 6514 receive video signals, clock signals, start signals, reset signals, etc. from the FPC6503, respectively. .. A printed circuit board (PWB) 6504 is attached to the FPC6503. The drive circuit unit does not necessarily have to be provided on the same substrate as the pixel unit 6511 as described above. For example, an IC chip mounted on an FPC on which a wiring pattern is formed (TCP) or the like is used. It may be used and provided outside the substrate.

A plurality of source signal lines extending in the column direction are arranged side by side in the row direction in the pixel unit 6511. In addition, the current supply lines are arranged side by side in the row direction. Further, in the pixel unit 6511, a plurality of gate signal lines extending in the row direction are arranged side by side in the column direction. Further, a plurality of sets of circuits including a light emitting element are arranged in the pixel unit 6511.

FIG. 11 is a diagram showing a circuit for operating one pixel. The circuit shown in FIG. 11 includes a first transistor 901, a second transistor 902, and a light emitting element 903. The first transistor 901 and the second transistor 902 are three-terminal elements including a gate electrode, a drain region, and a source region, respectively, and have a channel region between the drain region and the source region. Here, since the source region and the drain region change depending on the structure of the transistor, operating conditions, and the like, it is difficult to limit which is the source region or the drain region. Therefore, in this embodiment, the regions that function as the source or drain are referred to as the first electrode and the second electrode, respectively.

The gate signal line 911 and the writing gate signal line drive circuit 913 are provided so as to be electrically connected or disconnected by a switch 918. Further, the gate signal line 911 and the erasing gate signal line drive circuit 914 are provided so as to be electrically connected or disconnected by a switch 919. Further, the source signal line 912 is provided so as to be electrically connected to either the source signal line drive circuit 915 or the power supply 916 by the switch 920. The gate of the first transistor 901 is electrically connected to the gate signal line 911. Further, the first electrode of the first transistor 901 is electrically connected to the source signal line 912, and the second electrode is electrically connected to the gate electrode of the second transistor 902. The first electrode of the second transistor 902 is electrically connected to the current supply line 917, and the second electrode is electrically connected to one electrode included in the light emitting element 903. The switch 918 may be included in the writing gate signal line drive circuit 913. The switch 919 may also be included in the erasing gate signal line drive circuit 914. The switch 920 may also be included in the source signal line drive circuit 915.

The arrangement of the transistor, the light emitting element, and the like in the pixel portion is not particularly limited, but can be arranged as shown in the top view of FIG. 12, for example. In FIG. 12, the first electrode of the first transistor 1001 is connected to the source signal line 1004, and the second electrode is connected to the gate electrode of the second transistor 1002. Further, the first electrode of the second transistor 1002 is connected to the current supply line 1005, and the second electrode is connected to the electrode 1006 of the light emitting element. A part of the gate signal line 1003 functions as a gate electrode of the first transistor 1001.

Next, the driving method will be described. FIG. 13 is a diagram illustrating the operation of the frame over time. In FIG. 13, the horizontal direction represents the passage of time, and the vertical direction represents the number of scanning stages of the gate signal line.

When displaying an image using the light emitting device of the present invention, the screen rewriting operation and the display operation are repeatedly performed during the display period. The number of times of rewriting is not particularly limited, but it is preferable that the number of times of rewriting is at least about 60 times per second so that the viewer does not feel flicker. Here, the period during which one screen (one frame) is rewritten and displayed is referred to as one frame period.

As shown in FIG. 13, one frame is time-divided into four subframes 501, 502, 503, 504 including write periods 501a, 502a, 503a, 504a and retention periods 501b, 502b, 503b, 504b. .. The light emitting element to which the signal for emitting light is given is in the light emitting state during the holding period. The ratio of retention period lengths in each subframe is: 1st subframe 501: 2nd subframe 502: 3rd subframe 503: 4th subframe 504 = 2³:2²:2¹:2⁰= 8: 4: 2: 1. This makes it possible to express 4-bit gradation. However, the number of bits and the number of gradations are not limited to those described here, and for example, eight subframes may be provided so that 8-bit gradation can be performed.

The operation in one frame will be described. First, in the subframe 501, the writing operation is performed in order from the first line to the last line. Therefore, the start time of the write period differs depending on the line. The line from which the writing period 501a ends is moved to the holding period 501b in order. During the holding period, the light emitting element to which the signal for emitting light is given is in the light emitting state. Further, the line moves to the next subframe 502 in order from the line at which the retention period 501b ends, and the writing operation is performed in order from the first line to the last line as in the case of the subframe 501. The above operation is repeated until the retention period 504b of the subframe 504 is completed. When the operation in the subframe 504 is completed, the next frame is moved to. In this way, the integrated time of the light emission time in each subframe becomes the light emission time of each light emitting element in one frame. By changing the light emitting time for each light emitting element and combining them in various ways within one pixel, it is possible to form various display colors having different brightness and chromaticity.

If you want to forcibly end the retention period in a row that has already completed writing and has transitioned to the retention period before the writing to the last line is completed, as in subframe 504, after the retention period 504b. It is preferable to provide an erasing period of 504c and control the state so that the light is not emitted forcibly. Then, for the row that is forcibly turned into a non-light emitting state, the non-light emitting state is maintained for a certain period (this period is defined as the non-light emitting period 504d). Then, as soon as the writing period of the last line ends, the writing period of the next (or frame) is started in order from the first line. In order to write in the pixels of a certain line and input the erasing signal that makes the pixels non-emission to the pixels of a certain line, as shown in FIG. 15, one horizontal period is two. Divide into, one period is devoted to writing, and the other period is devoted to erasing. Within the divided horizontal period, each gate signal line 911 is selected and the corresponding signal at that time is input to the source signal line 912. For example, in one horizontal period, the first half selects the i-th line and the second half selects the j-th line. Then, in one horizontal period, it is possible to operate as if two lines were selected at the same time. That is, the video signal is written to the pixels in the writing periods 501a to 504a by using the writing period of each one horizontal period. Then, no pixel is selected during the erasing period of one horizontal period at this time. Further, the signal written to the pixel is erased in the erase period 504c by using another erase period of one horizontal period. At this time, no pixel is selected during the writing period of one horizontal period. As a result, it is possible to provide a display device having pixels having a high aperture ratio, and it is possible to improve the yield.

In this embodiment, the subframes 501 to 504 are arranged in order from the one having the longest retention period, but it is not always necessary to arrange them in the same order as in this embodiment, for example, they are arranged in order from the one having the shortest retention period. Alternatively, those having a long retention period and those having a short retention period may be randomly arranged. Further, the subframe may be further divided into a plurality of frames. That is, the gate signal line may be scanned a plurality of times during the period in which the same video signal is given.

Here, the operation of the circuit shown in FIG. 11 during the writing period and the erasing period will be described. First, the operation during the writing period will be described. During the writing period, the gate signal line 911 on the i-th line (i is a natural number) is electrically connected to the writing gate signal line driving circuit 913 via the switch 918, and is connected to the erasing gate signal line driving circuit 914. Is disconnected. Further, the source signal line 912 is electrically connected to the source signal line drive circuit 915 via a switch 920. Here, a signal is input to the gate of the first transistor 901 connected to the gate signal line 911 on the i-th line, and the first transistor 901 is turned on. At this time, the video signal is simultaneously input to the source signal lines from the first row to the last row. The video signals input from the source signal line 912 in each column are independent of each other. The video signal input from the source signal line 912 is input to the gate electrode of the second transistor 902 via the first transistor 901 connected to each source signal line. At this time, the on / off of the second transistor 902 is controlled by the signal input to the gate electrode of the second transistor 902. Then, when the second transistor 902 is turned on, a voltage is applied to the light emitting element 903, and a current flows through the light emitting element 903. That is, the light emission or non-emission of the light emitting element 903 is determined by the signal input to the gate electrode of the second transistor 902. For example, when the second transistor 902 is a P-channel type, the light emitting element 903 emits light when a Low Level signal is input to the gate electrode of the second transistor 902. On the other hand, when the second transistor 902 is an N-channel type, the light emitting element 903 emits light when a High Level signal is input to the gate electrode of the second transistor 902.

Next, the operation during the erasing period will be described. In the erasure period, the gate signal line 911 on the jth line (j is a natural number) is electrically connected to the erasure gate signal line drive circuit 914 via the switch 919, and is connected to the write gate signal line drive circuit 913. Not connected. Further, the source signal line 912 is electrically connected to the power supply 916 via the switch 920. Here, a signal is input to the gate of the first transistor 901 connected to the gate signal line 911 on the jth line, and the first transistor 901 is turned on. Then, at this time, the erasure signal is simultaneously input to the source signal lines from the first row to the last row. The erase signal input from the source signal line 912 is input to the gate electrode of the second transistor 902 via the first transistor 901 connected to each source signal line. At this time, the erasing signal input to the gate electrode of the second transistor 902 turns off the second transistor 902, and the supply of current from the current supply line 917 to the light emitting element 903 is blocked. Then, the light emitting element 903 is forcibly non-light emitting. For example, if the second transistor 902 is a P-channel type, the gate electrode of the second transistor 902 is set to High. When the Level signal is input, the light emitting element 903 does not emit light. On the other hand, when the second transistor 902 is an N-channel type, the light emitting element 903 does not emit light when a Low Level signal is input to the gate electrode of the second transistor 902.

In the erasing period, a signal for erasing is input for the jth line by the operation as described above. However, as described above, the jth line may be the erasure period, and the other lines (referred to as the ith line) may be the write period. In such a case, it is necessary to input the signal for erasing in the jth row and the signal for writing in the ith row using the source signal line in the same column, which will be described below. It is preferable to make such an operation.

Immediately after the light emitting element 903 on the j-1 line becomes non-light emitting due to the operation during the erasing period, the gate signal line 911 and the erasing gate signal line drive circuit 914 are disconnected, and the switch 920 Is switched to connect the source signal line 912 and the source signal line drive circuit 915. Then, the source signal line 912 and the source signal line drive circuit 915 are connected, and the switch 918 is switched to connect the gate signal line 911 and the writing gate signal line drive circuit 913. Then, a signal is selectively input from the writing gate signal line drive circuit 913 to the gate signal line 911 on the i-th line, the first transistor 901 is turned on, and one column from the source signal line drive circuit 915. A video signal for writing is input to the source signal line 912 from the first row to the last row. By this video signal, the light emitting element 903 in the i-th row emits light or does not emit light.

Immediately after the writing period for the i-th line is completed as described above, the deletion period for the j-th line is started. Therefore, the switch 918 is switched to disconnect the gate signal line and the writing gate signal line drive circuit 913, and the switch 920 is switched to connect the source signal line to the power supply 916. Further, the gate signal line 911 and the writing gate signal line drive circuit 913 are not connected, and the gate signal line 911 is connected to the erasing gate signal line drive circuit 914 by switching the switch 919. Then, a signal is selectively input from the erasing gate signal line drive circuit 914 to the gate signal line 911 on the jth line to turn on the first transistor 901, and the erasing signal is input from the power supply 916. Then, the light emitting element 903 is forcibly turned off by the erasing signal. In this way, as soon as the deletion period of the jth line is completed, the writing period of the i + 1th line is started. Hereinafter, similarly, the erasing period and the writing period may be repeated until the erasing period of the last line is operated.

In this embodiment, the mode in which the writing period of the i-th line is provided between the erasing period of the j-1th line and the erasing period of the j-th line has been described. The writing period of the i-th line may be provided between the period and the erasing period of the j + 1th line.

Further, in the present embodiment, when the non-emission period 504d is provided as in the subframe 504, the erasing gate signal line drive circuit 914 and a certain gate signal line are disconnected and the writing gate is provided. The operation of connecting the signal line drive circuit 913 and another gate signal line is repeated. Such an operation may be performed in a frame in which a non-light emitting period is not provided. In addition, this embodiment can be freely combined with the above-described embodiment or other embodiments.

The light emitting element according to the present invention is an EL element having a plurality of light emitting layers between a pixel electrode and a counter electrode, in which an intermediate conductive layer is provided between the light emitting layers and an intermediate conductive layer (a plurality of intermediate conductive layers are provided). In such cases, at least one of the intermediate conductive layers) is characterized in that either of the layers responsible for hole injection or electron injection is formed in an island shape rather than a film shape. By adopting such a structure, it is not necessary to consider the transparency of the material at all with respect to the layer into which electrons (or holes) are injected in the intermediate conductive layer, and most of the light emission from the light emitting layer is caused by the intermediate conductive layer. It is possible to produce various effects such as little absorption, no need to consider the crystallinity of the material of the intermediate conductive layer, and shortening of the manufacturing time of the device.

Further, a light emitting element having the above-mentioned effects can be adopted in a display device typified by an EL display. The display device has a method of forming a light emitting layer and an intermediate conductive layer between two types of striped electrodes provided so as to be orthogonal to each other (simple matrix method), or pixels connected to a TFT and arranged in a matrix. The light emitting element according to the present invention is roughly classified into two types, a method of forming a light emitting layer and an intermediate conductive layer between an electrode and a counter electrode (active matrix method), and the light emitting element according to the present invention is either a simple matrix method or an active matrix method. It can also be applied to. Further, the display device can be mounted on any electronic device or ubiquitous product such as an ID card, and the availability of the present invention is extremely wide.

<figref num="1">The figure explaining the structure of the light emitting element which concerns on this invention.</figref><figref num="2">The figure explaining the structure of the light emitting element which concerns on this invention.</figref><figref num="3">Equivalent circuit diagram (2 transistors) of the pixel area of the display device according to the present invention and top view of the display panel portion of the display device.</figref><figref num="4">Cross-sectional view of the display device according to the present invention</figref><figref num="5">Equivalent circuit diagram of the pixel area of the display device according to the present invention (3 and 4 transistors)</figref><figref num="6">Cross-sectional view showing the case where the wiring has a laminated structure</figref><figref num="7">The figure which shows the electronic device which used the display device which concerns on this invention.</figref><figref num="8">A block diagram showing a main configuration of a television device using the display device according to the present invention.</figref><figref num="9">The figure explaining the ID card using the display device which concerns on this invention.</figref><figref num="10">Top view of the light emitting device according to the present invention</figref><figref num="11">The figure which showed the circuit for operating one pixel in the light emitting device which concerns on this invention.</figref><figref num="12">Top view of a pixel region in the light emitting device according to the present invention</figref><figref num="13">The figure explaining the operation of the frame over time</figref><figref num="14">The figure explaining the structure of the conventional light emitting element</figref><figref num="15">Diagram illustrating how to select multiple gate signal lines at the same time in one horizontal period</figref><figref num="16">The figure explaining the structure of the light emitting element which concerns on this invention.</figref>

Code description

11: Anode 12: Cathode 13: Intermediate conductive layer (Alq: Li layer) 14: Intermediate conductive layer (In-Zn-O (indium / zinc oxide) layer) 15: Organic layer 16: Organic layer 17: Interlayer insulating film 101: Substrate 102: Anode 103: First light emitting layer 104: Layer responsible for electron injection 105: Layer responsible for hole injection 106: Second light emitting layer 107: Cathode 108: Third light emitting layer 203: 1st light emitting layer 204: Layer responsible for the first electron injection 205: Layer responsible for the first hole injection 206: Second light emitting layer 207: kth light emitting layer 208: Layer responsible for the kth electron injection 209: Layer responsible for kth hole injection 210: k + 1st light emitting layer 211: n-1st layer responsible for electron injection 212: layer responsible for n-1th hole injection 213: nth light emitting layer 310: pixels 311: Transistor 312: Transistor 313: Light emitting element 316: Capacitive element 317: First power supply 318: Second power supply 340: Transistor 341: Transistor 342: Transistor 343: Power supply 400: Luminous area 401: Gate driver 402: Gate driver 403: Source driver 405: Substrate 406: Opposed board 407: Connection film 408: Sealing material 409: Bulkhead layer 410: Element group 411: First interlayer insulating film 412: Second interlayer insulating film 414: Wiring 415: Translucent resin 416: Light-shielding bulkhead layer 417: Interlayer insulating film with light-shielding property 418: Space 501: Subframe 501a: Write period 501b: Retention period 502: Subframe 502a: Write period 502b: Retention period 503: Subframe 503a: Write period 503b: Retention period 504: Subframe 504a: Write period 504b: Retention period 504c: Erase period 504d: Non-luminous period 600: Mo 601: Alloy containing aluminum 602: ITO 603: Alloy containing aluminum 604: Alloy containing aluminum 605: ITO 606: Alloy containing aluminum 607: Nickel silicide 608: Silicon semiconductor layer 801: Card body 803: Card board 804: ID chip 805: Display device 806: Integrated circuit 807: Thin film part 808: Wiring 809: Antenna coil 701: EL display panel 702: Signal line side drive circuit 703: Scanning line side drive circuit 704: Tuner 705: Video wave amplifier circuit 706: Video signal processing circuit 707: Control circuit 708: Signal split circuit 709: Audio wave amplifier circuit 710: Audio signal processing circuit 711: Control circuit 712: Input section 713: Speaker 901: First transistor 902: Second transistor 903: Light emitting element 911: Gate signal line 912: Source signal line 913: Write gate signal line drive circuit 914: Erasing gate signal line drive circuit 915: Source signal line drive circuit 916: Power supply 917: Current supply line 918: Switch 919: Switch 920: Switch 1001: 1st transistor 1002: Second transistor 1003: Gate signal line 1004: Source signal line 1005: Current supply line 1006: Electrode of light emitting element 6500: Substrate 6503: FPC (Flexible Print Circuit) 6504: Printed Circuit Board (PWB) 6511: Pixel part 6512: Source signal line drive circuit 6513: Write gate signal line drive circuit 6514: Erasing gate signal line drive circuit 9101: Body 9102: Display 9201: Body 9202: Display 9301: Body 9302: Display 9401: Body 9402: Display 9501: Body 9502: Display 9701: Display 9702: Display