Light-emitting element

Abstract

To provide a multicolor light-emitting element in which light-emitting layers exhibiting different light colors are stacked, and in which the color can be easily adjusted, and provide a multicolor light-emitting element that is inexpensive and has good light-emitting efficiency.SOLUTION: There is provided a light-emitting element in which at least two light-emitting layers that emit different colors of light are formed in contact with each other, and in which light from both of the two light-emitting layers is obtained from an exciplex. The present invention also provides a light-emitting element in which the exciplex emits delayed fluorescence.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a light-emitting element, a display device, a light-emitting device, an electronic device, and a lighting device using an organic compound as a light-emitting substance. and a lighting device.

Background Art

[0002] In recent years, research and development of light-emitting elements (organic EL elements) using electroluminescence (EL) of organic compounds have been actively carried out. nescence) have been actively carried out. The basic configuration of these light-emitting elements is such that an organic compound layer (EL layer) containing a light-emitting substance is sandwiched between a pair of electrodes. By applying a voltage to this element, light emission from the light-emitting substance can be obtained. can be obtained. Since such a light-emitting element is a self-luminous type, it has advantages such as higher visibility of pixels compared to liquid crystal displays and the absence of a backlight, and is considered suitable as a flat panel display element. In addition, a display using such a light-emitting element can be manufactured to be thin and lightweight, which is also a great advantage. Furthermore, it is also characterized by a very fast response speed.

[0003] Since these light-emitting elements can form a light-emitting layer continuously in two dimensions, planar light emission can be obtained. Therefore, large-area elements can be easily formed. This is a characteristic that is difficult to obtain with point light sources typified by incandescent bulbs and LEDs, or line light sources typified by fluorescent lamps, and thus it also has high utility value as a surface light source applicable to lighting and the like. Since these light-emitting elements can form a light-emitting layer continuously in two dimensions, planar light emission can be obtained. Therefore, large-area elements can be easily formed. This is a characteristic that is difficult to obtain with point light sources typified by incandescent bulbs and LEDs, or line light sources typified by fluorescent lamps, and thus it also has high utility value as a surface light source applicable to lighting and the like. Since these light-emitting elements can form a light-emitting layer continuously in two dimensions, planar light emission can be obtained. Therefore, large-area elements can be easily formed. This is a characteristic that is difficult to obtain with point light sources typified by incandescent bulbs and LEDs, or line light sources typified by fluorescent lamps, and thus it also has high utility value as a surface light source applicable to lighting and the like. Since these light-emitting elements can form a light-emitting layer continuously in two dimensions, planar light emission can be obtained. Therefore, large-area elements can be easily formed. This is a characteristic that is difficult to obtain with point light sources typified by incandescent bulbs and LEDs, or line light sources typified by fluorescent lamps, and thus it also has high utility value as a surface light source applicable to lighting and the like. [[ID=3...]]

[0004] Since these light-emitting elements can form a light-emitting layer continuously in two dimensions, planar light emission can be obtained. Therefore, large-area elements can be easily formed. This is a characteristic that is difficult to obtain with point light sources typified by incandescent bulbs and LEDs, or line light sources typified by fluorescent lamps, and thus it also has high utility value as a surface light source applicable to lighting and the like. Since these light-emitting elements can form a light-emitting layer continuously in two dimensions, planar light emission can be obtained. Therefore, large-area elements can be easily formed. This is a characteristic that is difficult to obtain with point light sources typified by incandescent bulbs and LEDs, or line light sources typified by fluorescent lamps, and thus it also has high utility value as a surface light source applicable to lighting and the like. This is a characteristic that is difficult to obtain with point light sources typified by incandescent bulbs and LEDs, or line light sources typified by fluorescent lamps, and thus it also has high utility value as a surface light source applicable to lighting and the like. This is a characteristic that is difficult to obtain with point light sources typified by incandescent bulbs and LEDs, or line light sources typified by fluorescent lamps, and thus it also has high utility value as a surface light source applicable to lighting and the like.

[0005] In order to use the light-emitting element as lighting, it is essential to obtain white light emission. ​Light is usually obtained by applying a multicolor light-emitting device that exhibits light synthesized from a plurality of light-emitting center substances having different emission spectra. This is obtained by applying a multicolor light-emitting device.

[0006] In Patent Document 1, a configuration in which a layer for color adjustment is newly used in a light-emitting device in which a plurality of light-emitting layers are stacked is disclosed. However, in such a configuration, the number of components increases, which is disadvantageous in terms of cost. This is disadvantageous in terms of cost. [Prior Art Documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-033780 [Summary of the Invention] [Problems to be Solved by the Invention]

[0008] In the above-described multicolor light-emitting device, obtaining light emission of different wavelengths at the same time is equivalent to obtaining light emission from different energy levels at the same time. However, there is always a difference in height between the light from different energy levels, and as a result, energy transfer may occur. Therefore, in such a device, when obtaining a desired emission color, a detailed device design considering energy transfer is required, which takes a lot of time and labor.

[0009]

[0010] Therefore, an object of the present invention is to provide a light-emitting device in which a plurality of light-emitting layers having different emission colors are stacked and in which color adjustment is easy.

[0011] Another aspect of the present invention is to provide a multicolor light-emitting device that is inexpensive and has good luminous efficiency.

[0012] In another aspect of the present invention, there is a problem of providing a multi-color light-emitting element that is easy to adjust color, inexpensive, and has good luminous efficiency.

[0013] In one aspect of the present invention, there is a problem of providing a light-emitting device, a display device, an electronic device, and a lighting device that can be manufactured at low cost by using the above-described light-emitting element.

[0014] In one aspect of the present invention, there is a problem of providing a light-emitting device, a display device, an electronic device, and a lighting device with reduced power consumption by using the above-described light-emitting element.

[0015] The present invention only needs to achieve any one of the above-described problems.

Means for Solving the Problems

[0016] In a light-emitting element in which at least two light-emitting layers exhibiting different emission colors are formed in contact with each other, the above-described problems can be solved by obtaining all light from the light-emitting layer from an exciplex.

[0017] That is, one configuration of the present invention includes a first electrode, a second electrode, and an EL layer sandwiched between the first electrode and the second electrode, wherein the EL layer includes at least a light-emitting layer in which a first light-emitting layer and a second light-emitting layer are laminated, the first light-emitting layer includes a first organic compound and a second organic compound, the second light-emitting layer includes a third organic compound and a fourth organic compound, the first organic compound and the second organic compound form a combination that forms a first exciplex, and the third organic compound and the fourth organic compound form a combination that forms a second exciplex.

[0018] In a light-emitting device using a luminescent material that is not a normal exciplex, energy transfer occurs between luminescent materials, between host materials, and between a luminescent material and a host material due to differences in band gap and triplet excitation level. Therefore, in order to obtain light emission from a plurality of light-emitting layers, the adjustment of the light-emitting device, such as the device structure and doping concentration, becomes complicated. On the other hand, since energy transfer between exciplexes is unlikely to occur, in the light-emitting device having this configuration, light emission can be obtained from both light-emitting layers without much effort.

[0019] In addition, since the exciplex has a state in which the singlet excitation level and the triplet excitation level are close to each other, reverse intersystem crossing from the triplet excited state to the singlet excited state easily occurs, and it is likely to show delayed fluorescence. Since delayed fluorescence can convert the triplet excited state into fluorescence, it is possible to improve the luminous efficiency of the light-emitting device. In order to efficiently show delayed fluorescence, it is preferable that the difference between the singlet excited state and the triplet excited state is 0.2 eV or less, preferably 0.1 eV or less.

[0020] Therefore, another configuration of the present invention is a light-emitting device having the above configuration, wherein the first exciplex shows delayed fluorescence.

[0021] In addition, another configuration of the present invention is a light-emitting device having the above configuration, wherein the second exciplex shows delayed fluorescence.

[0022] In addition, another configuration of the present invention is a light-emitting device having the above configuration, wherein both the first exciplex and the second exciplex show delayed fluorescence.

[0023] In addition, another configuration of the present invention is a light-emitting element having the above configuration, wherein the external quantum efficiency is 5% or more.

[0024] Further, in the above light-emitting element, by setting the recombination region at the interface of each light-emitting layer, both light-emitting layers can emit light efficiently. Also, for the two substances that form an exciplex, since one is electron-transporting and the other is hole-transporting, it is advantageous for the formation of the exciplex. Furthermore, when one is electron-transporting and the other is hole-transporting, the transport properties of each light-emitting layer can be easily controlled by the mixing ratio of the two substances, and the recombination region can be easily adjusted.

[0025] That is, another configuration of the present invention is a light-emitting element having the above configuration, wherein the recombination region of electrons and holes in the light-emitting layer is at the interface between the first light-emitting layer and the second light-emitting layer.

[0026] In addition, another configuration of the present invention is a light-emitting element having the above configuration, wherein one of the first organic compound and the second organic compound is a substance having electron-transporting properties, and the other is a substance having hole-transporting properties, and one of the third organic compound and the fourth organic compound is a substance having electron-transporting properties, and the other is a substance having hole-transporting properties.

[0027] In addition, another configuration of the present invention is a light-emitting element having the above configuration, wherein one of the first electrode and the second electrode functions as an anode and the other functions as a cathode, and among the first light-emitting layer and the second light-emitting layer, the light-emitting layer located on the side of the electrode functioning as the anode has a substance having hole-transporting properties. The light-emitting layer located on the electrode side that contains a large amount and functions as a cathode contains a substance having electron-transporting properties. It is a light-emitting element that contains a large amount.

[0028] In addition, the light-emitting element can be a multi-color light-emitting element in which the emission wavelengths of the respective exciplexes are different, and the emission colors from the respective exciplexes are synthesized, and white light can be obtained by making the emissions complementary. That is, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first exciplex and the second exciplex emit light having peaks at different wavelengths. It is a light-emitting element.

[0029] That is, another configuration of the present invention is a light-emitting element having the above configuration, and the light-emitting spectrum has two peaks. It is a light-emitting element. It is.

[0030] Also, another configuration of the present invention is a light-emitting element having the above configuration, and the light-emitting spectrum has two peaks. It is a light-emitting element.

[0031] Also, another configuration of the present invention is a light-emitting element having the above configuration, and the light-emitting element exhibits white light. It is a white light-emitting element.

[0032] Also, the emission wavelength of the exciplex can be changed by changing one of the two substances forming the exciplex. That is, in a plurality of light-emitting layers, one of the substances constituting the exciplex can be commonly used, and by reducing the components, It becomes possible to fabricate the element more simply and inexpensively. It is possible to fabricate the element more simply and inexpensively. It becomes possible to fabricate the element more simply and inexpensively.

[0033] That is, another configuration of the present invention is a light-emitting element having the above configuration, wherein one of the first organic compound and the second organic compound and one of the third organic compound and the fourth organic compound are the same substance. It is a light-emitting element. It is a light-emitting element.

[0034] In addition, another configuration of the present invention includes a light-emitting element having the above-described configuration and means for controlling the light-emitting element. This is a light-emitting module obtained.

[0035] In addition, another configuration of the present invention has a light-emitting element having the above-described configuration in a display unit, and is a display module including means for controlling the light-emitting element.

[0036] In addition, another configuration of the present invention is a lighting device having a light-emitting element having the above-described configuration.

[0037] In addition, another configuration of the present invention is a light-emitting device including a light-emitting element having the above-described configuration and means for controlling the light-emitting element.

[0038] In addition, another configuration of the present invention has a light-emitting element having the above-described configuration in a display unit, and is a display device including means for controlling the light-emitting element.

[0039] In addition, another configuration of the present invention is an electronic device having a light-emitting element having the above-described configuration.

[0040] Note that the light-emitting device in this specification includes an image display device using a light-emitting element. Also, a module in which a connector, for example, an anisotropic conductive film or a TCP (Tape Carrier Package), is attached to the light-emitting element, a module in which a printed wiring board is provided at the tip of the TCP, or a module in which an IC (integrated circuit) is directly mounted on the light-emitting element by a COG (Chip On Glass) method are all included in the light-emitting device. Furthermore, a light-emitting device used in lighting fixtures and the like is also included.

Effects of the Invention

[0041] In one aspect of the present invention, in a multicolor light-emitting element in which light-emitting layers of different emission colors are laminated, color adjustment ​​​​​An easily light-emitting element of a node can be provided.

[0042] In another aspect of the present invention, a multi-color light-emitting element that is inexpensive and has good luminous efficiency can be provided. It can be done.

[0043] In another aspect of the present invention, a multi-color light-emitting element that is easy to adjust color, inexpensive, and has good luminous efficiency can be provided. It can be provided.

[0044] In another aspect of the present invention, by using the above-described light-emitting element, a light-emitting device, a display device, an electronic device, and a lighting device that can be manufactured at low cost can be provided respectively. It can be provided respectively.

[0045] In another aspect of the present invention, by using the above-described light-emitting element, a light-emitting device, a display device, an electronic device, and a lighting device with reduced power consumption can be provided respectively. It can be provided respectively.

Brief Description of Drawings

[0046]

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Embodiments for Carrying Out the Invention

[0047] Hereinafter, 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 it will be easily understood by those skilled in the art that the form and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention is not to be construed as limited to the description of the embodiments shown below .

[0048] (Embodiment 1) As a multi-color light-emitting element that obtains light from a plurality of light-emitting substances, those in which a plurality of light-emitting center substances are included in a single light-emitting layer, those in which a plurality of light-emitting layers are stacked and different light-emitting center substances are included in each light-emitting layer, those in which an intermediate layer is disposed between light-emitting layers containing different light-emitting center substances, etc. have been proposed .

[0049] Among these, except for the element using an intermediate layer, it is known that energy transfer occurs directly between the light-emitting center substances or via a host material, which has a great influence on the luminous efficiency and emission color .

[0050] The control of this energy transfer is achieved by the device structure, the selection of the host material and the light-emitting center substance, the presence or absence of additives and their amounts, etc., but a great deal of effort is required for the adjustment

[0051] In addition, the element using an intermediate layer has demerits such as an increase in the number of layers to be formed and an increase in cost, and a high driving voltage .

[0052] Therefore, in one aspect of the present invention, a first light-emitting layer and a second light-emitting layer are stacked, and each light-emitting In a multi-color light-emitting device in which light of different wavelengths is provided from an optical layer and the light is combined to exhibit light emission, a light-emitting device is provided in which the light obtained from the light-emitting layer is light emission from an exciplex. Here, a light-emitting device is provided in which the light obtained from the light-emitting layer is light emission from an exciplex.

[0053] FIG. 1 shows a schematic diagram of the light-emitting device according to the present embodiment. The light-emitting device according to the present embodiment has a structure in which an EL layer 103 is sandwiched between a first electrode 101 and a second electrode 102. The first electrode 101 and the second electrode 102 function as an anode and a cathode, respectively. In FIG. 1, the first electrode 101 functions as an anode, and the second electrode 102 functions as a cathode. This will be described.

[0054] The EL layer 103 has at least a light-emitting layer 113. Other layers in the EL layer 103 are not particularly limited. For example, as shown in FIG. 1, a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, an electron injection layer 115, and the like are included.

[0055] The light-emitting layer 113 is composed of a first light-emitting layer 113a and a second light-emitting layer 113b. The first light-emitting layer 113a contains at least a first organic compound and a second organic compound, and the second light-emitting layer 113b contains at least a third organic compound and a fourth organic compound. Note that the first light-emitting layer 113a may be composed only of the first organic compound and the second organic compound. Similarly, the second light-emitting layer 113b may be composed only of the third organic compound and the fourth organic compound. This may be the case.

[0056] Here, an exciplex is an excited state composed of two kinds of substances. An exciplex is, for example, in the case of photoexcitation, when one molecule in an excited state takes in a substance in the ground state of the other, It is formed. Therefore, when it returns to the ground state by emitting light, it behaves as the original substance. Thus, there is no ground state as an exciplex, and energy transfer to the exciplex cannot occur in principle. From this, the energy transfer between the light-emitting layers is suppressed, and the light-emitting device of this embodiment does not require complicated adjustment of the device structure due to energy transfer, and desired light emission can be easily obtained from both light-emitting layers.

[0057] An exciplex is composed of two types of organic compounds as described above. Therefore, the first light-emitting layer 113a contains at least a first organic compound and a second organic compound, and the second light-emitting layer 113b contains at least a third organic compound and a fourth organic compound. Also, the combination of the first organic compound and the second organic compound and the combination of the third organic compound and the fourth organic compound are each combinations in which at least an exciplex is formed.

[0058] As a combination of these two types of organic compounds, it is a preferable configuration that one is a compound that easily accepts electrons (a material having electron-transporting properties) and the other is a compound that easily accepts holes (a material having hole-transporting properties) because it is advantageous for the formation of an exciplex.

[0059] Further, since one of these two types of organic compounds is a material having electron-transporting properties and the other is a material having hole-transporting properties, the carrier balance of the light-emitting layer 113 can be easily adjusted by adjusting the content ratio in the light-emitting layer.

[0060] In the light-emitting device of this embodiment, by setting the carrier recombination region near the interface between the first light-emitting layer 113a and the second light-emitting layer 113b, the first light-emitting layer 113a and the second light-emitting layer 113b can be balanced well. ​ It is possible to distribute the excitation energy to the light-emitting layer 113b of 2, and the light emission from each light-emitting layer can be obtained without effort. Also, as described above, by combining the first organic compound to the fourth organic compound with a compound that easily receives electrons (a material having electron-transporting properties) and a compound that easily receives holes (a material having hole-transporting properties), by adjusting the mixing ratio, the recombination region can be easily controlled at the interface between the first light-emitting layer 113a and the second light-emitting layer 113b. By shifting the recombination region, since the light emission intensity from each light-emitting layer can also be controlled, the emission spectrum of the light-emitting element can be easily adjusted. In order to make the carrier recombination region near the interface between the first light-emitting layer 113a and the second light-emitting layer 113b, in the first light-emitting layer 113a and the second light-emitting layer 113b, the layer closer to the anode may be a hole-transporting layer, and the layer closer to the cathode may be an electron-transporting layer. Note that to form a hole-transporting layer, a material having hole-transporting properties may be contained in a large amount, and to form an electron-transporting layer, a material having electron-transporting properties may be contained in a large amount. In addition, the exciplex exhibits light emission derived from the energy difference between the HOMO level of the shallower (the one with a smaller absolute value) and the LUMO level of the deeper (the one with a larger absolute value) among the two substances forming the exciplex. Therefore, even if one of the substances is the same in the combination of the first organic compound and the second organic compound and the combination of the third organic compound and the fourth organic compound, light emission with different wavelengths can be obtained in the first light-emitting layer and the second light-emitting layer. By making one of the substances constituting the exciplex common in the first light-emitting layer and the second light-emitting layer,

[0061] As a result, the types of materials constituting the light-emitting element are reduced, and it becomes possible to manufacture more simply and inexpensively, and a light-emitting element suitable for mass production can be obtained. Further, since the injection barrier of carriers at the interface between the first light-emitting layer and the second light-emitting layer is reduced, it also contributes to the long life of the element. Here, as the types of excited states formed by the organic compound, there are a singlet excited state and a triplet excited state. The light emission from the singlet excited state (S1) is called fluorescence, and the light emission from the triplet excited state (T1) is called phosphorescence. Further, the statistical generation ratio in the light-emitting element is considered to be S1:T1 = 1:3. Therefore, a light-emitting element using a phosphorescent compound capable of converting the triplet excited state into light emission can achieve higher light emission efficiency than a light-emitting element using a fluorescent compound. Therefore, the development of light-emitting elements using phosphorescent compounds has been actively carried out in recent years. However, on the other hand, most of the currently used phosphorescent compounds are complexes having a rare metal such as iridium as a central metal, and there are concerns about their cost and supply stability. As a light-emitting mechanism capable of converting triplet excitation energy into light emission, in addition to the above phosphorescence, there is delayed fluorescence. This is a mechanism in which the triplet excited state undergoes reverse intersystem crossing to be upconverted to the singlet excited state and exhibits light emission. By using delayed fluorescence, it is also possible to obtain fluorescence emission exceeding 25%, which is regarded as the limit of the internal quantum efficiency of fluorescence emission.

[0062] This delayed fluorescence is more likely to occur as the singlet excited state and the triplet excited state are closer.

[0063]

[0064]

[0065] ​​​​​​​​​​​​​​Since the excited complex is in a state where the singlet excited state and the triplet excited state are close to each other, delayed fluorescence is easy to show. By using an excited complex that efficiently shows delayed fluorescence, the light-emitting element of this embodiment can also make the triplet excited state contribute to light emission, and it becomes possible to provide a light-emitting element with high luminous efficiency. Note that the delayed fluorescence includes what is called thermally activated delayed fluorescence (TADF) in which the efficiency of intersystem crossing is improved by a little heating (including self-heating). In order to efficiently express delayed fluorescence, it is preferable to make the energy gap between the singlet excited state and the triplet excited state be 0 eV to 0.2 eV. A more preferable configuration is one where the energy gap is 0 eV to 0.1 eV.

[0066] In addition, if either one of the light-emitting layers is a light-emitting layer that emits delayed fluorescence, the effect of improving the luminous efficiency can be obtained, but a configuration in which both light-emitting layers emit delayed fluorescence is more preferable .

[0067] In the case of a light-emitting element in which delayed fluorescence appears, the external quantum efficiency may exceed 5% (generation rate of singlet excited state 25% × light extraction efficiency 20%), which is said to be the theoretical limit of a fluorescent light-emitting element that hardly shows delayed fluorescence. In a light-emitting element having the configuration of the light-emitting element of this embodiment , a light-emitting element showing an efficiency exceeding 5% in external quantum efficiency can be estimated to have delayed fluorescence appearing efficiently .

[0068] Also, from another point of view, the EL internal quantum efficiency Φe1 (= Φp × 25% (generation rate of singlet excited state in EL)) estimated from the PL quantum yield Φp of the excited complex is smaller than the internal quantum efficiency Φe2 (external quantum efficiency ÷ 20% (light extraction efficiency)) of the light-emitting element, then delayed fluorescence is ​It can be said that it appears efficiently. When Φe2 is about twice that of Φe1, it is a preferable configuration because the effect of using the light-emitting element of the present embodiment appears. Since the effect of using the light-emitting element of the present embodiment appears, it is a preferable configuration.

[0069] The light-emitting element in the present embodiment having the above configuration obtains light from an exciplex that emits light with different emission wavelengths in the first light-emitting layer and the second light-emitting layer, respectively, thereby enabling a multi-color light-emitting light-emitting element. The emission spectrum of such a light-emitting element has at least two or more peaks. Also, even when the first light-emitting layer and the second light-emitting layer in the present embodiment are formed in contact with each other,

[0070] since it is difficult for energy transfer to occur between them, it is a light-emitting element in which the emission balance can be easily adjusted. Therefore, it can be suitably used as a light-emitting element that exhibits white light emission where control of the emission color is important, and is more effective as a light-emitting element for lighting applications.

[0071] The light-emitting element in the present embodiment having the above configuration uses an exciplex in the light-emitting layer, so that energy transfer between the light-emitting layers hardly occurs, and it can be a light-emitting element in which the color adjustment of the light-emitting element is easy.

[0072] Also, the light-emitting element of the present embodiment utilizes light emission from an exciplex and is likely to exhibit delayed fluorescence. By using delayed fluorescence, triplet excitation energy can be converted into light emission, so that a light-emitting element with high luminous efficiency can be obtained.

[0073] Also, the light-emitting element of the present embodiment uses an exciplex, so that energy transfer between the light-emitting layers is difficult to occur, and it can be a light-emitting element in which the color adjustment of the light-emitting element is easy. Also, the light-emitting element of the present embodiment can be a light-emitting element with high luminous efficiency because it can convert triplet excitation energy into light emission by utilizing delayed fluorescence.

[0074] Moreover, by using an exciplex, the light-emitting element of the present embodiment can easily adjust the energy transfer between the light-emitting layers. ​​Movement is less likely to occur and delayed fluorescence is easily obtained. Therefore, color adjustment is easy and the luminous efficiency is good. It can be made into a light-emitting element with good luminous efficiency.

[0075] (Embodiment 2) In this embodiment, an example of the detailed structure of the light-emitting element described in Embodiment 1 will be described below with reference to FIG. 1. It will be described below.

[0076] The light-emitting element in this embodiment has an EL layer composed of a plurality of layers between a pair of electrodes. In this embodiment, the light-emitting element includes a first electrode 101, a second electrode 102, and a first EL layer 103 provided between the first electrode 101 and the second electrode 102. In this embodiment, the first electrode 101 functions as an anode, and the second electrode 102 functions as a cathode as described below. That is, a voltage is applied to the first electrode 101 and the second electrode 102 so that the potential of the first electrode 101 is higher than that of the second electrode 10 2. When this is done, a configuration is adopted in which light emission can be obtained. When this is done, a configuration is adopted in which light emission can be obtained.

[0077] Since the first electrode 101 functions as an anode, it is preferably formed using a metal, alloy, conductive compound, or a mixture thereof having a large work function (specifically, 4.0e V or more). Specifically, for example, indium tin oxide (ITO: Indium T in Oxide), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, tungsten oxide, and indium oxide containing zinc oxide ( IWZO), etc. can be mentioned. These conductive metal oxide films are usually formed by sputtering, but may also be produced by applying a sol-gel method or the like. As an example of the production method IWZO), etc. can be mentioned. These conductive metal oxide films are usually formed by sputtering, but may also be produced by applying a sol-gel method or the like. As an example of the production method by sputtering, but it may also be produced by applying a sol-gel method or the like. As an example of the production method Indium oxide - zinc oxide can be formed by a sputtering method using a target to which 1 to 20 wt% of zinc oxide is added to indium oxide. There are also methods such as this. In addition, indium oxide containing tungsten oxide and zinc oxide (IWZO) can be formed by a sputtering method using a target containing 0.5 to 5 wt% of tungsten oxide and 0.1 to 1 wt% of zinc oxide with respect to indium oxide. In addition, indium oxide containing tungsten oxide and zinc oxide (IWZO) can be formed by a sputtering method using a target containing 0.5 to 5 wt% of tungsten oxide and 0.1 to 1 wt% of zinc oxide with respect to indium oxide. There are also methods such as this. In addition, indium oxide containing tungsten oxide and zinc oxide (IWZO) can be formed by a sputtering method using a target containing 0.5 to 5 wt% of tungsten oxide and 0.1 to 1 wt% of zinc oxide with respect to indium oxide. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or nitrides of metal materials (for example, titanium nitride) and the like can be mentioned. Graphene can also be used. By using the composite material described later for the layer in contact with the first electrode 101 in the EL layer 103, it becomes possible to select the electrode material regardless of the work function. By using the composite material described later for the layer in contact with the first electrode 101 in the EL layer 103, it becomes possible to select the electrode material regardless of the work function.

[0078] Regarding the laminated structure of the EL layer 103, as long as the light emitting layer 113 has the configuration shown in Embodiment 1, the others are not particularly limited. For example, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, a carrier blocking layer, an intermediate layer, etc. can be appropriately combined and configured. In this embodiment, the EL layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, a light emitting layer 113, an electron transport layer 114, and an electron injection layer 115 are sequentially laminated on the first electrode 101. A configuration having the above will be described. The materials constituting each layer will be specifically shown below. A configuration having the above will be described. The materials constituting each layer will be specifically shown below.

[0079] The hole injection layer 111 is a layer containing a substance with high hole injection properties. Molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. can be used. Molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. can be used. can be formed. In addition, phthalocyanine compounds such as phthalocyanine (abbreviation: H2Pc) and copper phthalocyanine (CuPC), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl) )-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis (3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-bip enyl)-4,4'-diamine (abbreviation: DNTPD), or polymers such as poly (ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS ) can also be used to form the hole injection layer 111.

[0080] In addition, as the hole injection layer 111, a composite material in which an acceptor substance is contained in a material having hole transport properties can be used. By using a material in which an acceptor substance is contained in a material having hole transport properties, the material for forming the electrode can be selected regardless of the work function of the electrode. That is, not only a material with a large work function but also a material with a small work function can be used as the first electrode 101. Examples of acceptor substances include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation : F4-TCNQ), chloranil, etc. In addition, transition metal oxides can be mentioned . In addition, oxides of metals belonging to Groups 4 to 8 in the periodic table can be mentioned . Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide , molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferred because they have high electron accepting properties . Among them, molybdenum oxide is particularly preferred because it is stable in the air, has low hygroscopicity, and is easy to handle .

[0081] Examples of materials having hole transporting properties for use in composite materials include aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and various organic compounds such as polymeric compounds (oligomers, dendrimers, polymers, etc.). It should be noted that the organic compound used in the composite material is preferably an organic compound having high hole transporting properties. Specifically, it is preferably a substance having a hole mobility of 10 cm -6 cm 2 / Vs or more. Hereinafter, organic compounds that can be used as materials having hole transporting properties in the composite material will be specifically listed.

[0082] For example, examples of aromatic amine compounds include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4- diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N ,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3 ,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), and the like. (abbreviation: DPA3B), and the like.

[0083] Examples of carbazole derivatives that can be used in the composite material specifically include 3-[N- (9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3 -yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2). ​​, 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino] -9-phenylcarbazole (abbreviation: PCzPCN1), etc. can be mentioned.

[0084] In addition, as carbazole derivatives that can be used in composite materials, there are also 4,4’- di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N- carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl- 9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis 4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. can be used.

[0085] In addition, as aromatic hydrocarbons that can be used in composite materials, for example, 2-tert -butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2- tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3, 5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9 ,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,1 0-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthra cene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAn th), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA) , 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene ene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7- Tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetram ethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,1 0'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl yl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaflu enyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, etc. may be mentioned. Fur thermore, pentacene, coronene, etc. can also be used. Thus, it is more -6 cm 2 / Vs or more hole mobility and using an aromatic hydrocarbon having 14 to 42 carbon atoms is more preferable.

[0086] Note that the aromatic hydrocarbon that can be used in the composite material may have a vinyl skeleton . Examples of the aromatic hydrocarbon having a vinyl group include, for example, 4,4'-bis(2,2- diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2- diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA), etc.

[0087] In addition, polymer compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphe nylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis (phenyl)benzidine] (abbreviation: Poly-TPD) can also be used. ​

[0088] By forming a hole injection layer, the injectability of holes is improved, and a light-emitting element with a low driving voltage can be obtained. It becomes possible to obtain.

[0089] The hole transport layer 112 is a layer containing a material having hole transport properties. Examples of materials having hole transport properties include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9'-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), and other aromatic amine compounds. The substances described here have high hole transport properties and are mainly substances having a hole mobility of 10 cm / Vs or more. Also, the organic compounds listed as materials having hole transport properties in the above composite materials can also be used in the hole transport layer 112. In addition, polymer compounds such as poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenylamine) (abbreviation: PVTPA) can also be used. Note that the layer containing a material having hole transport properties may be not only a single layer but also a laminate of two or more layers made of the above substances. As a material, for example, 4,4’-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N’-bis(3-methylphenyl)-N,N’-diphenyl- [1,1’-biphenyl]-4,4’-diamine (abbreviation: TPD), 4,4’,4 ’’-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4’,4’’-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4’-bis[N-(spiro-9,9’-bifluorene- 2-yl)-N―phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl- 4’-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPA FLP), etc. of aromatic amine compounds can be used. The substances described here have high hole transport properties and are mainly substances having a hole mobility of 10 cm -6 / Vs or more. Also, 2 the organic compounds listed as materials having hole transport properties in the above composite materials can also be used in the hole transport layer 1 12. In addition, polymer compounds such as poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenylamine) (abbreviation: PVTPA) can also be used. Note that the layer containing a material having hole transport properties may be not only a single layer but also a laminate of two or more layers made of the above substances. materials can also be used. Note that the layer containing a material having hole transport properties may be not only a single layer but also a laminate of two or more layers made of the above substances. The layer containing a material having hole transport properties may be not only a single layer but also a laminate of two or more layers made of the above substances. It may be a laminate of two or more layers of the above substances.

[0090] The light-emitting layer 113 has the configuration of the light-emitting layer 113 described in Embodiment 1. That is, from the first electrode side, the first light-emitting layer 113a and the second light-emitting layer 113b are laminated and configured. Moreover, the first light-emitting layer 113a contains a first organic compound and a second organic compound, and the second light-emitting layer 113b contains a third organic compound and a fourth organic compound. The feature of the light-emitting element of this embodiment is that the first organic compound and the second organic compound form a combination that forms a first excimer, and the third organic compound and the fourth organic compound form a combination that forms a second excimer. And it has a configuration for obtaining light emission from the first excimer and the second excimer.

[0091] As materials that can be used together with the above first organic compound, second organic compound, third organic compound, and fourth organic compound, there is no particular limitation as long as they satisfy the conditions described in Embodiment 1, and various carrier transport materials can be selected.

[0092] For example, as materials having electron transport properties (compounds that are easy to receive electrons), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis (2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis [2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), bis [2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), etc. of metal complexes, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1 ,3,4-Oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl TAZ ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazo OXD-7), 9-[4-(5-phenyl-1,3, 4-Oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11) , 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H- benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl )phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II Heterocyclic compounds with polyazole skeletons such as 2-[3-(dibenzothiophene- 4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-I I), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo [f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H- carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation Name: 2mCzBPDBq), 4,6-bis[3-(phenanthrene-9-yl)phenyl ]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothiene Diazine skeletons such as 4,6mDBTP2Pm-II) Heterocyclic compounds with hexagonal rings and 3,5-bis[3-(9H-carbazol-9-yl)phenyl] 1,3,5-tri[3-(3-pyridyl) Heterocyclic compounds with a pyridine skeleton, such as [-phenyl]benzene (abbreviation: TmPyPB) include. Among those described above, heterocyclic compounds having a diazine skeleton or a pyridine skeleton are preferable because of their good reliability. In particular, heterocyclic compounds having a diazine (pyrimidine or pyra zine) skeleton have high electron transport properties and contribute to reducing the driving voltage.

[0093] In addition, as materials having hole transport properties (compounds that easily accept holes), 4,4'- bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N, N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl] -4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bi fluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-f enyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BP AFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenyl amine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carb azole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphen yl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbre viation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carb azole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-na phthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phen yl-9H-carbazole-3-yl)phenyl]-fluorene-2-amine (abbreviation: PC BAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl) phenyl]-spiro-9,9'-bifluorene-2-amine (abbreviation: PCBASF), etc. Compounds having an aromatic amine skeleton such as, 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6 -bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP) , 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), etc. Compounds having a carbazole skeleton, 4,4',4''-(benzene-1,3,5-triyl )tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4- [4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene ( abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9-yl phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), etc. Compounds having a thiophene skeleton, 4,4',4''-(benzene-1,3,5-triyl )tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl 9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mm DBFFLBi-II), etc. Compounds having a furan skeleton can be mentioned. Among the above, , compounds having an aromatic amine skeleton and compounds having a carbazole skeleton have good reliability and are also preferable because they have high hole transportability and contribute to reducing the driving voltage.

[0094] In addition to the carrier transport materials described above, carrier transport materials can be used from known substances This is also acceptable. In addition, since the formed exciplex exhibits luminescence derived from the energy difference between the shallower HOMO level and the deeper LUMO level of the combined compounds, the combination of the first organic compound and the second organic compound and the combination of the third organic compound and the fourth organic compound are selected such that luminescence of a desired emission wavelength is achieved. Note that one of the first organic compound and the second organic compound and one of the third organic compound and the fourth organic compound may be the same substance. In this case, it becomes possible to reduce the types of materials constituting the light-emitting element, which is advantageous in terms of cost. Furthermore, by using one of these combinations as a material having electron-transporting properties and the other as a material having hole-transporting properties, it is advantageous for the formation of the exciplex. Also, by changing the content of each compound, the transport properties of the light-emitting layer can be easily adjusted, and the control of the recombination region can also be easily performed. The ratio of the content of the material having hole-transporting properties to the content of the material having electron-transporting properties may be Hole-transporting material: Electron-transporting material = 1:9 to 9:1. The light-emitting layer 113 having the above-described configuration can be formed by co-evaporation in a vacuum evaporation method, or by using an inkjet method, a spin coating method, a dip coating method, etc. as a mixed solution. In addition, in this embodiment, a configuration in which the first light-emitting layer 113a is formed on the anode side and the second light-emitting layer 113b is formed on the cathode side has been described, but the stacking order may be reversed. That is, the second light-emitting layer 113b may be formed on the anode side and the first light-emitting layer 113a may be formed on the cathode side.

[0095]

[0096]

[0097]

[0098] The configuration and effects of the light-emitting layer 113 other than those described above are the same as the configuration and effects described in Embodiment 1. Refer to the description of Embodiment 1. See the description of Embodiment 1.

[0099] The electron transport layer 114 is a layer containing a material having electron transporting properties. For example, tris(8-quinolinolato)aluminum (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum (abbreviation: BAlq), etc., are layers composed of metal complexes having a quinoline skeleton or a benzoquinoline skeleton. In addition, other metal complexes such as bis[2-(2-hydroxyphenyl)benzoxazolato]zinc (abbreviation: Zn(BOX)2), bis[2-(2-hydroxyphenyl)benzothiazolato]zinc (abbreviation: Zn(BTZ)2), etc., having oxazole-based and thiazole-based ligands can also be used. Furthermore, in addition to metal complexes, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OX-D-7), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), etc., can also be used. The substances described here have high electron transporting properties and mainly have an electron mobility of 10 cm / Vs or more. quinolinolato)aluminum (abbreviation: Alq), tris(4-methyl-8-quinolinolato )aluminum (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato )beryllium (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phe nylphenolato)aluminum (abbreviation: BAlq), etc., a quinoline skeleton or benzoquin oline skeleton consisting of metal complexes, etc. are layers. In addition, other bis[2-(2-hydrox yphenyl)benzoxazolato]zinc (abbreviation: Zn(BOX)2), bis[2-(2- hydroxyphenyl)benzothiazolato]zinc (abbreviation: Zn(BTZ)2), etc. oxa zole-based, thiazole-based ligand-containing metal complexes can also be used. Furthermore, in addition to metal complexes, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)- 1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(4-tert -butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OX D-7), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphe nyl)-1,2,4-triazole (abbreviation: TAZ), bathophenanthroline (abbreviation: B Phen), bathocuproine (abbreviation: BCP), etc. can also be used. The substances described here have high electron transportability and mainly have an electron mobility of 10 cm -6 / Vs or more 2 substances with electron mobility That is, the above-described electron-transporting host material may be used for the electron transport layer 114.

[0100] In addition, the electron transport layer 114 may be not only a single layer but also a laminate of two or more layers made of the above substances. It may be a laminate of two or more layers.

[0101] Also, a layer for controlling the movement of electron carriers may be provided between the electron transport layer and the light-emitting layer. This is a layer in which a small amount of a substance with high electron trapping property is added to a material with high electron transport property as described above, and by suppressing the movement of electron carriers, it becomes possible to adjust the carrier balance. This layer can adjust the carrier balance by suppressing the movement of electron carriers. Such a configuration has a great effect in suppressing problems (for example, reduction in device lifetime) caused by electrons passing through the light-emitting layer. This layer can adjust the carrier balance by suppressing the movement of electron carriers. Such a configuration has a great effect in suppressing problems (for example, reduction in device lifetime) caused by electrons passing through the light-emitting layer. This layer can adjust the carrier balance by suppressing the movement of electron carriers. Such a configuration has a great effect in suppressing problems (for example, reduction in device lifetime) caused by electrons passing through the light-emitting layer.

[0102] Also, an electron injection layer 115 may be provided between the electron transport layer 114 and the second electrode 102 in contact with the second electrode 102. As the electron injection layer 115, an alkali metal such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), or the like, an alkaline earth metal, or a compound thereof can be used. For example, a layer containing an alkali metal, an alkaline earth metal, or a compound thereof in a layer made of a substance having electron transport properties can be used. cesium fluoride (CsF), calcium fluoride (CaF2), or the like, an alkaline earth metal, or a compound thereof can be used. For example, a layer containing an alkali metal, an alkaline earth metal, or a compound thereof in a layer made of a substance having electron transport properties can be used. cesium fluoride (CsF), calcium fluoride (CaF2), or the like, an alkaline earth metal, or a compound thereof can be used. For example, a layer containing an alkali metal, an alkaline earth metal, or a compound thereof in a layer made of a substance having electron transport properties can be used. cesium fluoride (CsF), calcium fluoride (CaF2), or the like, an alkaline earth metal, or a compound thereof can be used. For example, a layer containing an alkali metal, an alkaline earth metal, or a compound thereof in a layer made of a substance having electron transport properties can be used. As the electron injection layer 115, by using a layer containing an alkali metal or an alkaline earth metal in a layer made of a substance having electron transport properties, electron injection from the second electrode 102 is more preferably performed efficiently.

[0103] As the material for forming the second electrode 102, a metal, an alloy, an electrically conductive compound, and a mixture thereof having a small work function (specifically, 3.8 eV or less) can be used. As the material for forming the second electrode 102, a metal, an alloy, an electrically conductive compound, and a mixture thereof having a small work function (specifically, 3.8 eV or less) can be used. Examples of such cathode materials include alkali metals such as lithium (Li) and cesium (Cs), and elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys containing these (MgAg, AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these. However, by providing an electron injection layer between the second electrode 102 and the electron transport layer, various conductive materials regardless of the work function, such as Al, Ag, ITO, indium tin oxide containing silicon or silicon oxide, can be used as the second electrode 102. These conductive materials can be formed into a film using a sputtering method, an inkjet method, a spin coating method, or the like. Moreover, as a method for forming the EL layer 103, various methods can be used regardless of whether it is a dry method or a wet method. For example, a vacuum evaporation method, an inkjet method, or a spin coating method may be used. Also, different film formation methods may be used for each electrode or each layer. Regarding the electrode, it may be formed by a wet method using the sol-gel method, or may be formed by a wet method using a paste of a metal material. Also, it may be formed using a dry method such as a sputtering method or a vacuum evaporation method. In the light-emitting element having the above configuration, a current flows due to the potential difference generated between the first electrode 101 and the second electrode 102, and in the light-emitting layer 113, which is a layer containing a highly light-emitting substance, 。 。 。

[0104] 。 。 。 。

[0105] 。 。 。

[0106] 。 。 Positive holes and electrons recombine and emit light. That is, a light-emitting region is formed in the light-emitting layer 113. It has such a configuration.

[0107] The light emission is taken out to the outside through either one or both of the first electrode 101 and the second electrode 102. Therefore, either one or both of the first electrode 101 and the second electrode 102 are made of a light-transmissive electrode. When only the first electrode 101 is a light-transmissive electrode the light emission is taken out through the first electrode 101. Also, when all of the second electrode 102 is a light-transmissive electrode, the light emission is taken out through the second electrode 102. When both the first electrode 101 and the second electrode 102 are light-transmissive electrodes the light emission is taken out from both through the first electrode 101 and the second electrode 102. Note that the configuration of the layer provided between the first electrode 101 and the second electrode 102 is not limited to the above. However, in order to suppress quenching caused by the light-emitting region where positive holes and electrons recombine being in close contact with the electrodes and the metal used in the carrier injection layer, a configuration in which a light-emitting region where positive holes and electrons recombine is provided at a site away from the first electrode 101 and the second electrode 102 is preferable.

[0108] In addition, the hole transport layer or electron transport layer in contact with the light-emitting layer 113, particularly the carrier transport layer in contact closer to the light-emitting region in the light-emitting layer 113, preferably has a band gap larger than the band gap of the exciplex contained in the light-emitting layer in order to suppress energy transfer from the excitons generated in the light-emitting layer.

[0109]

[0110] The light-emitting element in this embodiment is manufactured on a substrate made of glass, plastic, or the like. That's all right. As for the order of fabrication on the substrate, they may be laminated in order from the side of the first electrode 101, or may be laminated in order from the side of the second electrode 102. The light-emitting device may be one in which one light-emitting element is formed on one substrate, or a plurality of light-emitting elements may be formed. By fabricating a plurality of such light-emitting elements on one substrate, an element-divided lighting device or a passive matrix type light-emitting device can be fabricated. Also, on a substrate made of glass, plastic, etc., for example, a thin film transistor (TFT) may be formed, and a light-emitting element may be fabricated on an electrode electrically connected to the TFT. Thus, an active matrix type light-emitting device that controls the driving of the light-emitting element by the TFT can be fabricated. Note that the structure of the TFT is not particularly limited. It may be a staggered type TFT or an inverted staggered type TFT. Also, the crystallinity of the semiconductor used for the TFT is not particularly limited, and an amorphous semiconductor or a crystalline semiconductor may be used. Further, the driving circuit formed on the TFT substrate may also be composed of N-type and P-type TFTs, or may be composed of only either N-type TFT or P-type TFT. Note that this embodiment can be appropriately combined with other embodiments. (Embodiment 3) In this embodiment, a light-emitting device using the light-emitting element described in Embodiment 1 and Embodiment 2 will be described. In this embodiment, a light-emitting device fabricated using the light-emitting element described in Embodiment 1 and Embodiment 2 will be described with reference to FIG. 2. Note that FIG. 2(A) is a top view showing the light-emitting device.

[0111] Note that this embodiment can be appropriately combined with other embodiments.

[0112] (Embodiment 3) In this embodiment, a light-emitting device using the light-emitting element described in Embodiment 1 and Embodiment 2 will be described.

[0113] In this embodiment, a light-emitting device fabricated using the light-emitting element described in Embodiment 1 and Embodiment 2 will be described with reference to FIG. 2. Note that FIG. 2(A) is a top view showing the light-emitting device. , FIG. 2(B) is a cross-sectional view obtained by cutting FIG. 2(A) along A-B and C-D. This light-emitting device includes, as a component for controlling the light emission of the light-emitting element, a drive circuit section (source line drive circuit) 601 indicated by a dotted line, a pixel section 602, and a drive circuit section (gate line drive circuit) 603. Also, 604 is a sealing substrate, 605 is a sealing material, and the inside surrounded by the sealing material 605 is a space 607.

[0114] The routing wiring 608 is a wiring for transmitting signals input to the source line drive circuit 601 and the gate line drive circuit 603, and receives a video signal, a clock signal, a start signal, a reset signal, etc. from an FPC (flexible printed circuit) 609 which serves as an external input terminal. Although only the FPC is illustrated here, a printed wiring board (PWB) may be attached to this FPC. The light-emitting device in this specification includes not only the light-emitting device main body but also a state in which an FPC or a PWB is attached thereto.

[0115] Next, the cross-sectional structure will be described with reference to FIG. 2(B). A drive circuit section and a pixel section are formed on the element substrate 610. Here, one pixel in the source line drive circuit 601 which is a drive circuit section and the pixel section 602 are shown.

[0116] The source line drive circuit 601 is formed as a CMOS circuit combining an n-channel type TFT 623 and a p-channel type TFT 624. Also, the drive circuit may be formed of various CMOS circuits, PMOS circuits or NMOS circuits. Further, in this embodiment, a driver integrated type in which a drive circuit is formed on a substrate is shown, but this is not necessarily required, and the drive circuit ​​​​​​​​​​​​It can also be formed externally instead of on the substrate.

[0117] Further, the pixel portion 602 is formed by a plurality of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulator 614 is formed to cover the end portion of the first electrode 613. Here, it is formed by using a positive photosensitive acrylic resin film.

[0118] Also, in order to have good coverage, a curved surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614. For example, when a positive photosensitive acrylic is used as the material of the insulator 614, it is preferable to provide a curved surface having a curvature radius (0.2 μm to 3 μm) only at the upper end portion of the insulator 614. Further, as the insulator 614, either a negative photosensitive resin or a positive photosensitive resin can be used.

[0119] An EL layer 616 and a second electrode 617 are respectively formed on the first electrode 613. Here, as the material used for the first electrode 613 that functions as an anode, it is desirable to use a material having a large work function. For example, in addition to single-layer films such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt% of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, and a Pt film, a laminate of a titanium nitride film and a film mainly composed of aluminum, a three-layer structure of a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film can be used. Note that when a laminated structure is used, the resistance as a wiring is low, good ohmic contact can be obtained, and it can further function as an anode.

[0120] Also, the EL layer 616 is formed by various methods such as vapor deposition using a vapor deposition mask, inkjet method, spin coating method, etc. The EL layer 616 includes the configuration as described in Embodiment 1 and Embodiment 2 as described. Further, as other materials constituting the EL layer 616, a low molecular compound or a high molecular compound (including oligomers and dendrimers) may be used .

[0121] Furthermore, as the material used for the second electrode 617 formed on the EL layer 616 and functioning as a cathode, materials with a small work function (Al, Mg, Li, Ca, or alloys and compounds thereof (such as MgAg, MgIn, AlLi, etc.)) are preferably used. When the light generated in the EL layer 6 16 passes through the second electrode 617, a laminated structure of a thin metal film with a reduced film thickness and a transparent conductive film (ITO, indium tin oxide containing 2 - 20 wt% zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) is preferably used as the second electrode 617. 16 passes through the second electrode 617, a laminated structure of a thin metal film with a reduced film thickness and a transparent conductive film (ITO, indium tin oxide containing 2 - 20 wt% zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) is preferably used as the second electrode 617. 16 passes through the second electrode 617, a laminated structure of a thin metal film with a reduced film thickness and a transparent conductive film (ITO, indium tin oxide containing 2 - 20 wt% zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) is preferably used as the second electrode 617. for the second electrode 617. is good.

[0122] Note that a light - emitting element is formed by the first electrode 613, the EL layer 616, and the second electrode 617. The light - emitting element has the configuration of Embodiment 1 or Embodiment 2 of the light - emitting element. Note that the pixel portion is formed of a plurality of light - emitting elements. In the light - emitting device of the present embodiment, both the light - emitting element described in Embodiment 1 or Embodiment 2 and the light - emitting element having other configurations may be included. In the light - emitting device of the present embodiment, both the light - emitting element described in Embodiment 1 or Embodiment 2 and the light - emitting element having other configurations may be included.

[0123] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, a light - emitting element is placed in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605 element substrate 610, the sealing substrate 604, and the sealing material 605 The space 607 is filled with a filler. In addition to being filled with an inert gas (nitrogen, argon, etc.), it is also possible to fill it with a sealing material 605. If a recess is formed in the sealing substrate and a desiccant 625 is provided there, the sealing substrate can be protected from the influence of moisture. This is a preferable configuration because it can suppress deterioration due to the temperature change.

[0124] It is preferable to use epoxy resin or glass frit for the sealing material 605. In addition, it is desirable that these materials be as impermeable to moisture and oxygen as possible. The sealing substrate 604 may be made of a glass substrate, a quartz substrate, or a FRP (Fibre Reinforced Plastic) substrate. Glass-Reinforced Plastics), PVF (Polyvinyl Fluoride ), a plastic substrate made of polyester, acrylic, or the like can be used.

[0125] As described above, a light-emitting element manufactured using the light-emitting element described in Embodiment 1 or 2 A light emitting device having such a structure can be obtained.

[0126] The light-emitting device in this embodiment includes the light-emitting element described in Embodiment 1 or 2. Since the organic EL element is used, a light emitting device having good characteristics can be obtained. The light-emitting element described in Embodiment 1 or 2 is a light-emitting element with high luminous efficiency and low power consumption. In addition, the light emitting device shown in Embodiment 1 or 2 can be provided with reduced light emission. The light emitting element is easy to manufacture, and therefore an inexpensive light emitting device can be provided. do.

[0127] In FIG. 3, a light emitting element that emits white light is formed, and a colored layer (color filter) or the like is provided. FIG. 3(A) shows an example of a full-color light-emitting device. an insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, 1008, a first the first interlayer insulating film 1020, the second interlayer insulating film 1021, the peripheral portion 1042, the pixel portion 1040, The driving circuit unit 1041, the first electrodes 1024W, 1024R, 1024G, 10 24B, a partition wall 1025, an EL layer 1028, a second electrode 1029 of the light-emitting element, and a sealing substrate 10 31, sealing material 1032, etc. are shown.

[0128] In addition, in FIG. 3(A), the colored layers (red colored layer 1034R, green colored layer 1034G, blue The colored layer 1034B is provided on the transparent substrate 1033. A transparent substrate on which a colored layer and a black layer are provided may be further provided. 1033 is aligned and fixed to the substrate 1001. The colored layer and the black layer are In FIG. 3(A), the colored layer is covered with an overcoat layer 1036. There are light-emitting layers that emit light to the outside without passing through the color layers of each color, and light-emitting layers that emit light to the outside. The light that does not pass through the colored layer is white, and the light that passes through the colored layer is red, blue, and green. Images can be expressed using pixels.

[0129] In FIG. 3(B), the colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer An example in which a layer 1034B) is formed between the gate insulating film 1003 and the first interlayer insulating film 1020 As shown in the figure, the colored layer is provided between the substrate 1001 and the sealing substrate 1031. is also good.

[0130] In the light emitting device described above, light is taken in from the substrate 1001 side on which the TFT is formed. A light-emitting device having a structure in which light is extracted from the bottom emission side (bottom emission type) is used, but a light-emitting device having a structure in which light is extracted from the sealing substrate 1031 side (top emission type) may also be used. A cross-sectional view of the top emission type light-emitting device is shown in FIG. 4. In this case, the substrate 1001 can be a substrate that does not transmit light. Until a connection electrode connecting the TFT and the anode of the light-emitting element is formed, it is formed in the same manner as the bottom emission type light-emitting device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may serve as a planarization film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film or other known materials. A light-emitting device having a structure in which light is extracted from the top emission side (top emission type) may also be used. A cross-sectional view of the top emission type light-emitting device is shown in FIG. 4. In this case, the substrate 1001 can be a substrate that does not transmit light. Until a connection electrode connecting the TFT and the anode of the light-emitting element is formed, it is formed in the same manner as the bottom emission type light-emitting device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may serve as a planarization film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film or other known materials. A cross-sectional view of the top emission type light-emitting device is shown in FIG. 4. In this case, the substrate 1001 can be a substrate that does not transmit light. Until a connection electrode connecting the TFT and the anode of the light-emitting element is formed, it is formed in the same manner as the bottom emission type light-emitting device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may serve as a planarization film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film or other known materials. A light-emitting device having a structure in which light is extracted from the bottom emission side (bottom emission type) is used, but a light-emitting device having a structure in which light is extracted from the sealing substrate 1031 side (top emission type) may also be used. A cross-sectional view of the top emission type light-emitting device is shown in FIG. 4. In this case, the substrate 1001 can be a substrate that does not transmit light. Until a connection electrode connecting the TFT and the anode of the light-emitting element is formed, it is formed in the same manner as the bottom emission type light-emitting device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may serve as a planarization film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film or other known materials. A light-emitting device having a structure in which light is extracted from the bottom emission side (bottom emission type) is used, but a light-emitting device having a structure in which light is extracted from the sealing substrate 1031 side (top emission type) may also be used. A cross-sectional view of the top emission type light-emitting device is shown in FIG. 4. In this case, the substrate 1001 can be a substrate that does not transmit light. Until a connection electrode connecting the TFT and the anode of the light-emitting element is formed, it is formed in the same manner as the bottom emission type light-emitting device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may serve as a planarization film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film or other known materials. A light-emitting device having a structure in which light is extracted from the bottom emission side (bottom emission type) is used, but a light-emitting device having a structure in which light is extracted from the sealing substrate 1031 side (top emission type) may also be used. A cross-sectional view of the top emission type light-emitting device is shown in FIG. 4. In this case, the substrate 1001 can be a substrate that does not transmit light. Until a connection electrode connecting the TFT and the anode of the light-emitting element is formed, it is formed in the same manner as the bottom emission type light-emitting device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may serve as a planarization film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film or other known materials. A light-emitting device having a structure in which light is extracted from the bottom emission side (bottom emission type) is used, but a light-emitting device having a structure in which light is extracted from the sealing substrate 1031 side (top emission type) may also be used. A cross-sectional view of the top emission type light-emitting device is shown in FIG. 4. In this case, the substrate 1001 can be a substrate that does not transmit light. Until a connection electrode connecting the TFT and the anode of the light-emitting element is formed, it is formed in the same manner as the bottom emission type light-emitting device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may serve as a planarization film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film or other known materials. A light-emitting device having a structure in which light is extracted from the bottom emission side (bottom emission type) is used, but a light-emitting device having a structure in which light is extracted from the sealing substrate 1031 side (top emission type) may also be used. A cross-sectional view of the top emission type light-emitting device is shown in FIG. 4. In this case, the substrate 1001 can be a substrate that does not transmit light. Until a connection electrode connecting the TFT and the anode of the light-emitting element is formed, it is formed in the same manner as the bottom emission type light-emitting device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may serve as a planarization film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film or other known materials.

[0131] The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting element are anodes here, but they may be cathodes. Also, in the case of a top emission type light-emitting device as shown in FIG. 4, it is preferable that the first electrode is a reflective electrode. The configuration of the EL layer 1028 is the same as the configuration described for the EL layer 103 in Embodiment 1 or Embodiment 2, and an element structure capable of obtaining white light emission is used. The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting element are anodes here, but they may be cathodes. Also, in the case of a top emission type light-emitting device as shown in FIG. 4, it is preferable that the first electrode is a reflective electrode. The configuration of the EL layer 1028 is the same as the configuration described for the EL layer 103 in Embodiment 1 or Embodiment 2, and an element structure capable of obtaining white light emission is used. The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting element are anodes here, but they may be cathodes. Also, in the case of a top emission type light-emitting device as shown in FIG. 4, it is preferable that the first electrode is a reflective electrode. The configuration of the EL layer 1028 is the same as the configuration described for the EL layer 103 in Embodiment 1 or Embodiment 2, and an element structure capable of obtaining white light emission is used. The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting element are anodes here, but they may be cathodes. Also, in the case of a top emission type light-emitting device as shown in FIG. 4, it is preferable that the first electrode is a reflective electrode. The configuration of the EL layer 1028 is the same as the configuration described for the EL layer 103 in Embodiment 1 or Embodiment 2, and an element structure capable of obtaining white light emission is used. The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting element are anodes here, but they may be cathodes. Also, in the case of a top emission type light-emitting device as shown in FIG. 4, it is preferable that the first electrode is a reflective electrode. The configuration of the EL layer 1028 is the same as the configuration described for the EL layer 103 in Embodiment 1 or Embodiment 2, and an element structure capable of obtaining white light emission is used.

[0132] In the top emission structure as shown in FIG. 4, sealing can be performed with a sealing substrate 1031 provided with a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B). A black layer (black matrix) 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) and the black layer (black matrix) are over In the top emission structure as shown in FIG. 4, sealing can be performed with a sealing substrate 1031 provided with a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B). A black layer (black matrix) 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) and the black layer (black matrix) are over In the top emission structure as shown in FIG. 4, sealing can be performed with a sealing substrate 1031 provided with a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B). A black layer (black matrix) 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) and the black layer (black matrix) are over In the top emission structure as shown in FIG. 4, sealing can be performed with a sealing substrate 1031 provided with a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B). A black layer (black matrix) 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) and the black layer (black matrix) are over In the top emission structure as shown in FIG. 4, sealing can be performed with a sealing substrate 1031 provided with a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B). A black layer (black matrix) 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) and the black layer (black matrix) are over It may be covered by the coat layer 1036. Note that the sealing substrate 1031 has translucency. A substrate will be used.

[0133] Also, here, an example of full-color display using four colors of red, green, blue, and white has been shown, but it is not particularly limited. Full-color display may be performed using three colors of red, green, and blue.

[0134] Since the light-emitting device in this embodiment uses the light-emitting element described in Embodiment 1 or Embodiment 2, a light-emitting device having good characteristics can be obtained. Specifically, the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element with good luminous efficiency, and a light-emitting device with reduced power consumption can be obtained. Also, since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive light-emitting device can be provided.

[0135] So far, the active matrix type light-emitting device has been described. From below, a passive matrix type light-emitting device will be described. FIG. 5 shows a passive matrix type light-emitting device manufactured by applying the present invention. Note that FIG. 5(A) is a perspective view showing the light-emitting device, and FIG. 5(B) is a cross-sectional view obtained by cutting FIG. 5(A) along X-Y. In FIG. 5, on a substrate 951, an EL layer 955 is provided between an electrode 952 and an electrode 956. The end of the electrode 952 is covered with an insulating layer 953. And a partition layer 954 is provided on the insulating layer 953. The side walls of the partition layer 954 have an inclination such that the interval between one side wall and the other side wall becomes narrower as it approaches the substrate surface. That is, the cross-section of the partition layer 954 in the short side direction is trapezoidal, with the bottom side (facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) The side) faces upward (in the same direction as the surface direction of the insulating layer 953) and is shorter than the side that does not contact the insulating layer 953. ) By providing the partition layer 954 in this way, defects in the light-emitting element caused by static electricity or the like can be prevented. Further, in a passive matrix type light-emitting device, a light-emitting element having good luminous efficiency shown in Embodiment 1 or Embodiment 2 is used, and a light-emitting device with reduced power consumption can be obtained. Also, since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive light-emitting device can be provided. As described above, the light-emitting device can be suitably used as a display device for displaying an image because it is possible to control each of a large number of minute light-emitting elements arranged in a matrix.

[0136] Furthermore, the light-emitting device described above can be freely combined with other embodiments.

[0137] (Embodiment 4)

[0138] In this embodiment, an example of using the light-emitting element described in Embodiment 1 or Embodiment 2 as an illumination device will be described with reference to FIG. 6. FIG. 6(B) is a top view of the illumination device, and FIG. 6(A) is a cross-sectional view taken along the line e-f in FIG. 6(B).

[0139] In the illumination device according to this embodiment, a first electrode 401 is formed on a translucent substrate 400 which is a support. The first electrode 401 corresponds to the first electrode 101 in Embodiment 1. When extracting light from the side of the first electrode 401, the first electrode 401 is formed of a translucent material.

[0140] A pad 412 for supplying a voltage to the second electrode 404 is formed on the substrate 400.

[0141] An EL layer 403 is formed on the first electrode 401. The EL layer 403 corresponds to the configuration of the EL layer 103 in Embodiment 1. For these configurations, please refer to the relevant description. Please refer to the relevant description.

[0142] The second electrode 404 is formed to cover the EL layer 403. The second electrode 404 corresponds to the second electrode 102 in Embodiment 1. When extracting light emission from the first electrode 401 side, the second electrode 404 is formed of a material with high reflectivity. The second electrode 404 is connected to the pad 412, and thus a voltage is supplied. When extracting light emission from the first electrode 401 side, the second electrode 404 is formed of a material with high reflectivity. The second electrode 404 is connected to the pad 412, and thus a voltage is supplied. 2, and thus a voltage is supplied. 2, and thus a voltage is supplied.

[0143] As described above, the lighting device shown in this embodiment has a light-emitting element having the first electrode 401, the EL layer 403, and the second electrode 404. Since the light-emitting element has high luminous efficiency, the lighting device in this embodiment can be a lighting device with low power consumption. As described above, the lighting device shown in this embodiment has a light-emitting element having the first electrode 401, the EL layer 403, and the second electrode 404. Since the light-emitting element has high luminous efficiency, the lighting device in this embodiment can be a lighting device with low power consumption. Since the light-emitting element has high luminous efficiency, the lighting device in this embodiment can be a lighting device with low power consumption. Also, the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture. Therefore, an inexpensive lighting device can be provided. Therefore, an inexpensive lighting device can be provided.

[0144] The lighting device is completed by adhering and sealing the sealing substrate 407 using the sealing materials 405 and 406 to the light-emitting element having the above configuration. Either of the sealing materials 405 and 406 may be used. Also, a desiccant can be mixed into the inner sealing material 406 (not shown in FIG. 6(B)), whereby moisture can be adsorbed, leading to an improvement in reliability. The lighting device is completed by adhering and sealing the sealing substrate 407 using the sealing materials 405 and 406 to the light-emitting element having the above configuration. Either of the sealing materials 405 and 406 may be used. Either of the sealing materials 405 and 406 may be used. Also, a desiccant can be mixed into the inner sealing material 406 (not shown in FIG. 6(B)), whereby moisture can be adsorbed, leading to an improvement in reliability.

[0145] Further, by extending a part of the pad 412 and the first electrode 401 outside the sealing materials 405 and 406, it can be used as an external input terminal. Also, an IC chip 420 or the like on which a converter or the like is mounted may be provided thereon. Since the lighting device described in the present embodiment has the light-emitting element described in Embodiment 1 or Embodiment 2 for the EL element, it can be a lighting device with low power consumption. Also, it can be a lighting device with a low driving voltage. Further, since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive light-emitting device can be provided.

[0146] As described above, Since the lighting device described in the present embodiment has the light-emitting element described in Embodiment 1 or Embodiment 2 for the EL element, it can be a lighting device with low power consumption. Also, it can be a lighting device with a low driving voltage. Further, since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive light-emitting device can be provided. Since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive light-emitting device can be provided.

[0147] (Embodiment 5) In the present embodiment, an example of an electronic device including a part of the light-emitting element described in Embodiment 1 or Embodiment 2 will be described. The light-emitting element described in Embodiment 1 or Embodiment 2 is a light-emitting element with good luminous efficiency and reduced power consumption. As a result, the electronic device described in the present embodiment can be an electronic device having a light-emitting portion with reduced power consumption. Also, Since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive electronic device can be provided. Since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive electronic device can be provided. Since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive electronic device can be provided. Since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive electronic device can be provided. Since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive electronic device can be provided.

[0148] Examples of electronic devices to which the above light-emitting element is applied include, for example, a television device (also referred to as a TV or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone (also referred to as a mobile phone or a mobile phone device ), a portable game machine, a portable information terminal, an audio playback device, a large game machine such as a pachinko machine, etc. ) ​include. Specific examples of these electronic devices are shown below.

[0149] FIG. 7(A) shows an example of a television device. The television device has a housing 710 1 in which a display unit 7103 is incorporated. Here, a configuration is shown in which the housing 7101 is supported by a stand 7105. The display unit 7103 can display video, and the display unit 7103 is configured by arranging the light-emitting elements described in Embodiment 1 and Embodiment 2 in a matrix pattern. The light-emitting element can be a light-emitting element with good luminous efficiency. Also, it can be a light-emitting element with a small driving voltage. Also, it can be a light-emitting element with a long lifespan. Therefore, the television device having the display unit 7 103 composed of the light-emitting elements can be a television device with reduced power consumption. Also, it can be a television device with a small driving voltage. Also, it can be an inexpensive television device.

[0150] The operation of the television device can be performed by an operation switch provided in the housing 7101 or by a separate remote control operation device 7110. The operation keys 7109 provided in the remote control operation device 7110 can be used to operate the channel and volume, and the video displayed on the display unit 7103 can be operated. Also, the remote control operation device 7110 may be configured to include a display unit 7107 for displaying information output from the remote control operation device 7110 .

[0151] Note that the television device has a configuration including a receiver, a modem, etc. The receiver can receive general television broadcasts, and further communicate by wire or wirelessly via a modem By connecting to a network, it is also possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication. It is also possible to perform information communication in one direction (from the sender to the receiver) or two directions (between the sender and the receiver, or between the receivers) by connecting to a network.

[0152] Figure 7(B1) is a computer, including a main body 7201, a housing 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. Note that this computer is manufactured by arranging light-emitting elements in a matrix and using them for the display unit 7203. The computer in Figure 7(B1) may be in the form shown in Figure 7(B2). The computer in Figure 7(B2) is provided with a second display unit 7210 instead of the keyboard 7204 and the pointing device 7206. The second display unit 7210 is a touch panel type, and input can be performed by operating the input display shown on the second display unit 7210 with a finger or a dedicated pen. In addition, the second display unit 7210 can display not only input displays but also other images. The display unit 7203 may also be a touch panel. By connecting the two screens with a hinge, it is possible to prevent problems such as damaging or breaking the screens during storage or transportation. Note that this computer is manufactured by arranging the light-emitting elements described in Embodiment 1 and Embodiment 2 in a matrix and using them for the display unit 7203. The light-emitting element can be a light-emitting element with good luminous efficiency. Therefore, the computer having the display unit 7203 composed of the light-emitting element can be a computer with reduced power consumption. Also, it can be an inexpensive computer. It is also possible to perform information communication in one direction (from the sender to the receiver) or two directions (between the sender and the receiver, or between the receivers) by connecting to a network. By connecting the two screens with a hinge, it is possible to prevent problems such as damaging or breaking the screens during storage or transportation. Note that this computer is manufactured by arranging the light-emitting elements described in Embodiment 1 and Embodiment 2 in a matrix and using them for the display unit 7203. The light-emitting element can be a light-emitting element with good luminous efficiency. Therefore, the computer having the display unit 7203 composed of the light-emitting element can be a computer with reduced power consumption. Also, it can be an inexpensive computer. It is also possible to perform information communication in one direction (from the sender to the receiver) or two directions (between the sender and the receiver, or between the receivers) by connecting to a network. By connecting the two screens with a hinge, it is possible to prevent problems such as damaging or breaking the screens during storage or transportation.

[0153] FIG. 7(C) shows a portable gaming machine, which is composed of two housings, a housing 7301 and a housing 7302, and is connected in an openable and closable manner by a connecting portion 7303. The housing 7301 incorporates a display portion 7304 manufactured by arranging the light-emitting elements described in Embodiment 1 and Embodiment 2 in a matrix, and the housing 7302 incorporates a display portion 7305. In addition, the portable gaming machine shown in FIG. 7(C) further includes a speaker portion 7306, a recording medium insertion portion 7307, an LED lamp 7308, input means (operation keys 7309, connection terminals 7310, sensors 7311 (including functions for measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone 7312), etc. Of course, the configuration of the portable gaming machine is not limited to the above, and it is sufficient if at least one of the display portions 7304 and 7305 uses a display portion manufactured by arranging the light-emitting elements described in Embodiment 1 and Embodiment 2 in a matrix, and other accessories can be appropriately provided. The portable gaming machine shown in FIG. 7(C) has a function of reading a program or data recorded on a recording medium and displaying it on the display portion, and a function of sharing information by performing wireless communication with other portable gaming machines. Note that the functions of the portable gaming machine shown in FIG. 7(C) are not limited to this, and it can have various functions. A portable gaming machine having a display portion 7304 as described above can be a portable gaming machine with reduced power consumption because the light-emitting elements used in the display portion 7304 have good luminous efficiency. and is connected in an openable and closable manner by a connecting portion 7303. The housing 7301 incorporates a display portion 7304 manufactured by arranging the light-emitting elements described in Embodiment 1 and Embodiment 2 in a matrix. and the housing 7302 incorporates a display portion 7305. In addition, the portable gaming machine shown in FIG. 7(C) further includes a speaker portion 7306, a recording medium insertion portion 7307, an LED lamp 7308, input means (operation keys 7309, connection terminals 7310, sensors 73 11 (including functions for measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone (7312), etc. Of course, the configuration of the portable gaming machine is not limited to the above, and it is sufficient if at least one of the display portions 7304 and 7305 uses a display portion manufactured by arranging the light-emitting elements described in Embodiment 1 and Embodiment 2 in a matrix, and other accessories can be appropriately provided. The portable gaming machine shown in FIG. 7(C) has a function of reading a program or data recorded on a recording medium and displaying it on the display portion, and a function of sharing information by performing wireless communication with other portable gaming machines. Note that the functions of the portable gaming machine shown in FIG. 7(C) are not limited to this, and it can have various functions. A portable gaming machine having a display portion 7304 as described above can be a portable gaming machine with reduced power consumption because the light-emitting elements used in the display portion 7304 have good luminous efficiency. The portable gaming machine shown in FIG. 7(C) has a function of reading a program or data recorded on a recording medium and displaying it on the display portion, and a function of sharing information by performing wireless communication with other portable gaming machines. Note that the functions of the portable gaming machine shown in FIG. 7(C) are not limited to this, and it can have various functions. A portable gaming machine having a display portion 7304 as described above can be a portable gaming machine with reduced power consumption because the light-emitting elements used in the display portion 7304 have good luminous efficiency. A portable gaming machine having a display portion 7304 as described above can be a portable gaming machine with reduced power consumption because the light-emitting elements used in the display portion 7304 have good luminous efficiency. In addition, the light-emitting element used in the display portion 7304 can be driven at a low driving voltage. Therefore, it is possible to provide a portable gaming machine with a low driving voltage. The light-emitting element shown in Embodiment 1 or 2 is a light-emitting element that is easy to manufacture and therefore inexpensive. It is possible to provide a portable gaming machine.

[0154] FIG. 7D shows an example of a mobile phone. The mobile phone is built in a housing 7401. In addition to the display unit 7402, operation buttons 7403, an external connection port 7404, a speaker 74 05, a microphone 7406, etc. The mobile phone 7400 is and the light-emitting elements described in Embodiment 2 are arranged in matrix in the display portion 7402. The light-emitting element can have high luminous efficiency. It is possible to provide a light emitting element with a low driving voltage. Therefore, a mobile phone having a display portion 7402 including the light-emitting element can be used. The mobile phone can be a mobile phone with reduced power consumption. The light-emitting element shown in Embodiment 1 or 2 can be used as a telephone. Since the LED is a light emitting element that is easy to manufacture, it is possible to provide an inexpensive mobile phone.

[0155] The mobile phone shown in FIG. 7D allows a user to input information by touching the display portion 7402 with a finger or the like. In this case, the user can make a call or create an email. Such operations can be performed by touching the display portion 7402 with a finger or the like.

[0156] The screen of the display unit 7402 has three main modes. The first is a display mode that mainly displays images. is a display mode, and the second is an input mode mainly for inputting information such as characters. The third is a display + input mode in which two modes of a display mode and an input mode are mixed.

[0157] For example, when making a phone call or creating an email, the display unit 7402 may be set to the character input mode mainly for character input, and an input operation on the characters displayed on the screen may be performed. In this case , it is preferable to display a keyboard or number buttons on most of the screen of the display unit 7402.

[0158] Also, by providing a detection device having sensors such as a gyro and an acceleration sensor inside the mobile phone to detect the inclination, the orientation (portrait or landscape) of the mobile phone can be determined, and the screen display of the display unit 7402 can be automatically switched.

[0159] Also, the switching of the screen mode is performed by touching the display unit 7402 or operating the operation button 7403 of the housing 7401. Also, it can be switched according to the type of image displayed on the display unit 7402. For example, if the image signal displayed on the display unit is video data, it is switched to the display mode, and if it is text data, it is switched to the input mode.

[0160] Also, in the input mode, the signal detected by the optical sensor of the display unit 7402 is detected, and when there is no input by touch operation of the display unit 7402 for a certain period, the screen mode may be controlled to be switched from the input mode to the display mode.

[0161] The display unit 7402 can also function as an image sensor. For example, the display unit 74 ​​​​​​​​​By touching 02 with the palm or fingers and imaging palm prints, fingerprints, etc., personal authentication can be performed. Also, by using a backlight that emits near-infrared light or a light source for sensing that emits near-infrared light in the display unit, it is also possible to image finger veins, palm veins, etc.

[0162] Note that the configuration shown in this embodiment can be used by appropriately combining the configurations shown in Embodiments 1 to 4.

[0163] As described above, the application range of the light-emitting device including the light-emitting element described in Embodiment 1 and Embodiment 2 is extremely wide, and this light-emitting device can be applied to electronic devices in all fields. By using the light-emitting element described in Embodiment 1 and Embodiment 2, an electronic device with reduced power consumption can be obtained. In addition, since the light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element that is easy to manufacture, an inexpensive electronic device can be provided.

[0164] FIG. 8 is an example of a liquid crystal display device in which the light-emitting element described in Embodiment 1 and Embodiment 2 is applied to a backlight. The liquid crystal display device shown in FIG. 8 has a housing 901, a liquid crystal layer 902, a backlight unit 903, and a housing 904. The liquid crystal layer 902 is connected to a driver IC 905. In addition, the light-emitting element described in Embodiment 1 and Embodiment 2 is used in the backlight unit 903, and current is supplied through a terminal 906.

[0165] By applying the light-emitting element described in Embodiment 1 and Embodiment 2 to the backlight of a liquid crystal display device, a backlight with reduced power consumption can be obtained. Also, by using the light-emitting element described in Embodiment 2, a surface-emitting lighting device can be manufactured, and it is also possible to increase the area. This enables the enlargement of the area of the backlight, and also enables the enlargement of the area of the liquid crystal display device. Furthermore, the light-emitting device to which the light-emitting element described in Embodiment 2 is applied can have a smaller thickness compared with the conventional one, and thus the display device can be made thinner.

[0166] FIG. 9 shows an example in which the light-emitting element described in Embodiment 1 and Embodiment 2 is used for an electric stand which is a lighting device. The electric stand shown in FIG. 9 has a housing 2001 and a light source 2002, and the lighting device described in Embodiment 4 is used as the light source 2002.

[0167] FIG. 10 shows an example in which the light-emitting element described in Embodiment 1 and Embodiment 2 is used as an indoor lighting device 3001. Since the light-emitting element described in Embodiment 1 and Embodiment 2 is a light-emitting element with reduced power consumption, it can be used as a lighting device with reduced power consumption. In addition, since the light-emitting element described in Embodiment 1 and Embodiment 2 can be enlarged in area, it can be used as a large-area lighting device. Moreover, since the light-emitting element described in Embodiment 1 and Embodiment 2 is thin, it can be used as a thin lighting device.

[0168] The light-emitting element described in Embodiment 1 and Embodiment 2 can also be mounted on the windshield or dashboard of an automobile. FIG. 11 shows an aspect in which the light-emitting element described in Embodiment 2 is used for the windshield or dashboard of an automobile. Displays 5000 to 5005 are displays provided using the light-emitting element described in Embodiment 1 and Embodiment 2.

[0169] Displays 5000 and 5001 are those of Embodiment 1 and Embodiment 2 provided on the windshield of an automobile. A display device equipped with the light-emitting element described in Embodiment 2. The light-emitting elements described in Embodiment 1 and Embodiment 2 are fabricated using electrodes with light-transmitting properties for the first electrode and the second electrode. Therefore, it is possible to obtain a so-called see-through display device where the opposite side can be seen through. In the case of a see-through display, even if it is installed on the windshield of an automobile, it can be installed without obstructing the view. Note that when providing transistors or the like for driving, it is preferable to use light-transmitting transistors such as organic transistors made of an organic semiconductor material or transistors using an oxide semiconductor.

[0170] Display 5002 is a display device equipped with the light-emitting elements described in Embodiment 1 and Embodiment 2 provided in the pillar portion. Display 5002 can complement the view blocked by the pillar by projecting the video from the imaging means provided on the vehicle body. Similarly, display 5003 provided in the dashboard portion can compensate for the blind spot and enhance safety by projecting the video from the imaging means provided outside the vehicle body to complement the view blocked by the vehicle body. By projecting the video so as to complement the invisible part, it is possible to perform safety confirmation more naturally without a sense of discomfort.

[0171] Displays 5004 and 5005 can provide various other information such as navigation information, speedometer, tachometer, travel distance, fuel supply amount, gear state, air conditioner settings, etc. The display can appropriately change the display items and layout according to the user's preference. Note that this information can also be provided on Displays 5000 to 5003. In addition, the displays 5000 to 5005 can also be used as lighting devices.

[0172] The light-emitting elements described in Embodiments 1 and 2 are light-emitting elements with high luminous efficiency. In addition, it is possible to make a light emitting device with low power consumption. Even if many large screens are installed on the 5000 to 5005, the battery will not be overloaded. Therefore, the number of the people who use the device is small and the device can be used comfortably. The light-emitting device or lighting device using the light-emitting element is suitable as an in-vehicle light-emitting device or lighting device. It can be used for.

[0173] Figures 12(A) and 12(B) show an example of a foldable tablet terminal. 2(A) shows the tablet terminal in an open state, and the tablet terminal includes a housing 9630, a display unit 9631a, and a , display unit 9631b, display mode changeover switch 9034, power switch 9035, A power mode changeover switch 9036, a fastener 9033, and an operation switch 9038 are included. The tablet terminal is equipped with the light-emitting element described in the first and second embodiments. By using the light-emitting device having the above configuration in one or both of the display portion 9631a and the display portion 9631b, It is produced.

[0174] A part of the display unit 9631a can be used as a touch panel area 9632a. By touching the operation keys 9637, data can be input. In 1a, for example, half of the area has a display function only, and the other half The display unit 963 has a touch panel function, but is not limited to this. All areas of 1a may also be configured to have touch panel functions. For example, the display unit 96 The entire surface of 31a can be made to display keyboard buttons to serve as a touch panel, and the display unit 9631b can be used as a display screen.

[0175] Also, in the display unit 9631b as well as in the display unit 9631a, a part of the display unit 9631b can be made into a touch panel area 9632b. Also, by touching the position where the keyboard display switching button 9639 of the touch panel is displayed with a finger or a stylus, etc., keyboard buttons can be displayed on the display unit 9631b.

[0176] Also, touch input can be performed simultaneously on the touch panel area 9632a and the touch panel area 9632b.

[0177] Also, the display mode switching switch 9034 can switch the display orientation such as portrait or landscape display, and can select switching between black and white display and color display, etc. The power saving mode switching switch 9036 can optimize the display brightness according to the amount of external light detected during use by a light sensor built into the tablet type terminal. The tablet type terminal may incorporate not only a light sensor but also other detection devices such as sensors for detecting inclination such as a gyro and an acceleration sensor.

[0178] Also, in Fig. 12(A), an example where the display areas of the display unit 9631b and the display unit 9631a are the same is shown, but it is not particularly limited, and one size and the other size may be different, and the display quality may also be different. For example, one may be a display panel that can perform higher definition display than the other.

[0179] Figure 12(B) is in a closed state. In the tablet terminal according to the present embodiment, the housing 9630, solar cell 9633, charge / discharge control circuit 9634, battery 9635, DCD C converter 9636 are provided. In FIG. 12(B), a configuration having a battery 9635 and a DCDC converter 9636 is shown as an example of the charge / discharge control circuit 963 4. is shown.

[0180] Since the tablet terminal is foldable in two, the housing 9630 can be closed when not in use. Therefore, the display units 9631a and 9631b can be protected, and a tablet terminal with excellent durability and reliability from the perspective of long-term use can be provided.

[0181] In addition, the tablet terminals shown in FIGS. 12(A) and 12(B) can also have functions such as displaying various information (still images, moving images, text images, etc.), a calendar, a date or a time on the display unit, a touch input function for touch input operation or editing of the information displayed on the display unit, and a function for controlling processing by various software (programs).

[0182] Power can be supplied to the touch panel, the display unit, or the video signal processing unit, etc. by the solar cell 9633 mounted on the surface of the tablet terminal. The solar cell 9633 is preferably provided on one or two sides of the housing 9630 because it can be configured to efficiently charge the battery 9635.

[0183] In addition, regarding the configuration and operation of the charge / discharge control circuit 9634 shown in FIG. 12(B), refer to FIG. 12( ​​​​​C) is shown in a block diagram and described. In Fig. 12(C), a solar cell 9633, a battery 9 635, a DCDC converter 9636, a converter 9638, switches SW1 to SW3 are shown. The battery 9635, the DCDC converter 963 6, the converter 9638, and the switches SW1 to SW3 correspond to the locations of the charge / discharge control circuit 9634 shown in Fig. 12(B).

[0184] First, an example of the operation when power is generated by the solar cell 9633 due to external light will be described . The power generated by the solar cell becomes a voltage for charging the battery 9635, and is stepped up or down by the DC DC converter 9636. When the power charged by the solar cell 9633 is used for the operation of the display unit 9631, the switch SW1 is turned on, and the con verter 9638 steps up or down the voltage to the voltage required for the display unit 9631. Also , when the display on the display unit 9631 is not performed, SW1 is turned off and SW2 is turned on to charge the ba ttery 9635.

[0185] Note that the solar cell 9633 is shown as an example of a power generation means, but the power generation means is not particularly limited, and other power generation means such as piezoelectric elements (piezo elements) and thermoelectric conversion elements (Peltier elements) may be used to charge the battery 9635. It may be configured to charge wirelessly (non-contact) by transmitting and receiving power, or by combining other charging means , and it may not have a power generation means.

[0186] Also, if the above display unit 9631 is provided, it is not limited to the tablet-type terminal having the shape shown in Fig. 12 .

Description of Symbols

[0187] 101 First electrode 102 Second electrode 103 EL layer 111 Hole injection layer 112 Hole transport layer 113 Light-emitting layer 113a First light-emitting layer 113b Second light-emitting layer 114 Electron transport layer 115 Electron injection layer 400 Substrate 401 First electrode 403 EL layer 404 Second electrode 405 Sealing material 406 Sealing material 407 Sealing substrate 412 Pad 420 IC chip 601 Driving circuit section (source line driving circuit) 602 Pixel section 603 Driving circuit section (gate line driving circuit) 604 Sealing substrate 605 Sealing material 607 Space 608 Wiring 609 FPC (Flexible Printed Circuit) 610 Element substrate 611 Switching TFT 612 Current control TFT 613 First electrode 614 Insulator 616 EL layer 617 Second electrode 618 Light-emitting element 623 n-channel TFT 624 p-channel TFT 625 Drying material 901 Housing 902 Liquid crystal layer 903 Backlight unit 904 Housing 905 Driver IC 906 Terminal 951 Substrate 952 Electrode 953 Insulating Layer 954 Partition Layer 955 EL Layer 956 Electrode 1001 Substrate 1002 Underlying Insulating Film 1003 Gate Insulating Film 1006 Gate Electrode 1007 Gate Electrode 1008 Gate Electrode 1020 First Interlayer Insulating Film 1021 Second Interlayer Insulating Film 1022 Electrode 1024W First Electrode of Light-Emitting Element 1024R First Electrode of Light-Emitting Element 1024G First Electrode of Light-Emitting Element 1024B First Electrode of Light-Emitting Element 1025 Partition 1028 EL Layer 1029 Second Electrode of Light-Emitting Element 1031 Sealing Substrate 1032 Sealing Material 1033 Transparent Substrate 1034R Red Coloring Layer 1034G Green Coloring Layer 1034B Blue Coloring Layer 1035 Black Layer (Black Matrix) 1036 Overcoat Layer 1037 Third Interlayer Insulating Film 1040 Pixel Section 1041 Driving Circuit Section 1042 Peripheral Section 2001 Housing 2002 Light Source 3001 Lighting Device 5000 Display 5001 Display 5002 Display 5003 Display 5004 Display 5005 indicates 7101 housing 7103 display section 7105 stand 7107 display section 7109 operation key 7110 remote control operation unit 7201 main body 7202 housing 7203 display section 7204 keyboard 7205 external connection port 7206 pointing device 7210 second display section 7301 housing 7302 housing 7303 connecting section 7304 display section 7305 display section 7306 speaker section 7307 recording medium insertion section 7308 LED lamp 7309 operation key 7310 connection terminal 7311 sensor 7401 housing 7402 display section 7403 operation button 7404 external connection port 7405 speaker 7406 microphone 7400 mobile phone 9033 fastener 9034 switch 9035 power switch 9036 switch 9038 operation switch 9630 housing 9631 display section 9631a display section 9631b display section 9632a touch panel area 9632b touch panel area 9633 solar cell 9634 Charge and Discharge Control Circuit 9635 Battery 9636 DC / DC Converter 9637 Operation Key 9638 Converter 9639 Button

Claims

【Claim 1】 An EL element having a first electrode, a second electrode, and an EL layer sandwiched between the first electrode and the second electrode, wherein the EL layer has at least a light-emitting layer in which a first light-emitting layer and a second light-emitting layer are laminated, the first light-emitting layer contains a first organic compound and a second organic compound, the second light-emitting layer contains a third organic compound and a fourth organic compound, the first organic compound and the second organic compound are a combination that forms a first exciplex, and the third organic compound and the fourth organic compound are a combination that forms a second exciplex.

Images