Light-emitting device

Abstract

A light emitting device in which leakage current between electrodes of a light emitting element is reduced is provided. [Solution] One aspect relates to a light-emitting device having a first electrode arranged on a main surface of an element substrate, an insulating layer having an opening, an organic layer having a light-emitting layer, and a second electrode, wherein the highest occupied molecular orbital (HOMO) level of a first compound in the organic layer is higher than the HOMO level of a second compound in the organic layer, the organic layer has a first region in contact with the first electrode at the opening and a second region arranged on the inclined portion, and the concentration of the first compound in the first region is higher than the concentration of the first compound in the second region.

Description

[Technical Field]

[0001] The present disclosure relates to a light-emitting device, a display device, a photoelectric conversion device, an electronic device, eyeglasses, an image forming device, and a moving object. [Background technology]

[0002] As a light-emitting device using an organic layer, a light-emitting device having an organic light-emitting element has been proposed. The organic light-emitting element is an element having an upper electrode, a lower electrode, and an organic layer disposed between them, and emits light by exciting the organic compound contained in the organic layer.

[0003] Known methods for forming organic layers of organic light-emitting elements include a method for forming organic layers with different configurations for each emitted color, and a method for forming organic layers with the same configuration regardless of the emitted color. In the method for forming organic layers with the same configuration regardless of the emitted color, a continuous organic layer is typically formed across multiple light-emitting elements. Even when organic layers with different configurations for each emitted color are formed, some organic layers may be connected to multiple light-emitting elements.

[0004] Patent Document 1 discloses a technique for suppressing leakage by increasing the film thickness of an organic layer in a direction perpendicular to the inclined portion of an insulating layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-136260 Summary of the Invention [Problem to be solved by the invention]

[0006] To electrically isolate pixels from adjacent pixels, light-emitting devices have insulating layers that separate pixels (and sub-pixels). At the sloped portions of the insulating layers, the organic layers can become thinner, which can cause leakage current between the upper and lower electrodes.

[0007] However, depending on the structure of the light-emitting device described in Patent Document 1 and the material of the organic layer, it may not be possible to make the organic layer thick enough on the inclined portion.

[0008] The present disclosure provides a light emitting device with reduced leakage current between the upper electrode and the lower electrode. [Means for solving the problem]

[0009] One embodiment of the present disclosure relates to a light-emitting device including: a first electrode disposed on a principal surface of an element substrate; an insulating layer disposed on the element substrate and the first electrode, the insulating layer having an opening above the first electrode; an organic layer disposed on the first electrode and the insulating layer, the organic layer having a light-emitting layer; and a second electrode disposed on the organic layer, wherein in a cross section passing through the first electrode, the opening, and the organic layer, an end of the insulating layer has a sloped portion that is inclined with respect to the principal surface; the organic layer includes a first compound and a second compound, the highest occupied molecular orbital (HOMO) level of the first compound is higher than the HOMO level of the second compound; the organic layer includes a first region in contact with the first electrode at the opening and a second region disposed on the sloped portion; and a concentration of the first compound in the first region is higher than a concentration of the first compound in the second region.

[0010] Another aspect of the present disclosure relates to a light-emitting device comprising: a first electrode disposed on a principal surface of an element substrate; an insulating layer disposed on the element substrate and the first electrode, the insulating layer having an opening above the first electrode; an organic layer disposed on the first electrode and the insulating layer, the organic layer having a light-emitting layer; and a second electrode disposed on the organic layer, wherein in a cross section passing through the first electrode, the opening, and the organic layer, an end of the insulating layer has a sloped portion that is sloped with respect to the principal surface; the organic layer comprises a first compound and a second compound, the lowest unoccupied molecular orbital (LUMO) level of the first compound is lower than the LUMO level of the second compound; the organic layer has a first region in contact with the first electrode at the opening and a second region disposed on the sloped portion; and the concentration of the first compound in the first region is higher than the concentration of the first compound in the second region. [Effects of the Invention]

[0011] According to one aspect of the present disclosure, it is possible to provide a light emitting device in which leakage current between a lower electrode and an upper electrode is reduced. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating an example of the configuration of a portion of a light-emitting device according to an embodiment. [Figure 2] FIG. 1 is a plan view schematically illustrating an example of the configuration of a portion of a light emitting device according to an embodiment. [Figure 3] FIG. 2 is an enlarged cross-sectional view schematically illustrating an example of the configuration of a portion of the light-emitting device according to the embodiment. [Figure 4] 5A and 5B are conceptual diagrams for explaining energy of the light emitting device according to the embodiment. [Figure 5] FIG. 3 is a conceptual diagram for explaining carrier movement in an organic layer according to the embodiment. [Figure 6] FIG. 3 is a conceptual diagram for explaining carrier movement in an organic layer according to the embodiment. [Figure 7] FIG. 3 is a conceptual diagram for explaining carrier movement in an organic layer according to the embodiment. [Figure 8]FIG. 3 is a conceptual diagram for explaining carrier movement in an organic layer according to the embodiment. [Figure 9] FIG. 3 is a diagram illustrating the arrangement of components during vapor deposition according to the embodiment. [Figure 10] FIG. 3 is an enlarged view of the arrangement of members during vapor deposition according to the embodiment. [Figure 11] FIG. 2 is an enlarged plan view of a mask opening according to an embodiment. [Figure 12] FIG. 1 is a cross-sectional view schematically illustrating an example of the configuration of a portion of a light-emitting device according to an embodiment. [Figure 13] FIG. 2 is an enlarged plan view of a mask opening according to an embodiment. [Figure 14] 1A is a plan view schematically illustrating an example of the configuration of a portion of a light-emitting device according to an embodiment, and FIG. 1B is an enlarged plan view of a mask opening according to an embodiment. [Figure 15] 1A is a plan view schematically illustrating an example of the configuration of a portion of a light-emitting device according to an embodiment, and FIG. 1B is an enlarged plan view of a mask opening according to an embodiment. [Figure 16] FIG. 2 is a schematic cross-sectional view illustrating an example of a pixel of the display device according to the embodiment. [Figure 17] FIG. 1 is a schematic diagram illustrating an example of a display device according to an embodiment. [Figure 18] 1A is a schematic diagram illustrating an example of an imaging device according to an embodiment, and FIG. 1B is a schematic diagram illustrating an example of an electronic device according to an embodiment. [Figure 19] 1A is a schematic diagram illustrating an example of a display device according to an embodiment, and FIG. 1B is a schematic diagram illustrating an example of a foldable display device. [Figure 20] FIG. 1A is a schematic diagram showing an example of a wearable device according to an embodiment, and FIG. 1B is a schematic diagram showing an example of a wearable device according to an embodiment, the wearable device having an imaging device. [Figure 21] 1A is a schematic diagram of an image forming apparatus according to an embodiment, and FIGS. 1B and 1C are schematic diagrams showing an embodiment in which a plurality of light-emitting portions of an exposure light source are arranged on a long substrate. [Figure 22] 1 is a schematic diagram showing an example of an automobile having a vehicle lamp and a display unit according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a specific embodiment of a light emitting device according to one embodiment of the present invention will be described with reference to the accompanying drawings. Note that in the following description and drawings, common reference numerals are used to designate components common to multiple drawings. Therefore, the common components will be described with mutual reference to multiple drawings, and descriptions of components with common reference numerals will be omitted as appropriate.

[0014] [First embodiment] This embodiment shows an example of a light-emitting device. FIG. 1 is a cross-sectional view schematically showing an example of the configuration of a portion of an organic light-emitting device 100 according to this embodiment. FIG. 2 is a plan view schematically showing an example of the configuration of a portion of the organic light-emitting device 100. The cross section taken along line A-A' in FIG. 2 corresponds to FIG. 1, and three sub-pixels SP form one pixel. This embodiment shows an example of pixels in a delta arrangement, but the arrangement is not limited to this and may be a stripe arrangement, a pentile arrangement, a honeycomb arrangement, or the like.

[0015] The organic light-emitting device 100 includes an element substrate 1 and a plurality of light-emitting elements 10 arranged on the element substrate 1. FIG. 1 shows three light-emitting elements 10R, 10G, and 10B among the plurality of light-emitting elements 10 included in the organic light-emitting device 100. The "R" in 10R indicates that it is an element that emits red light. Similarly, 10G and 10B indicate that they emit green and blue light, respectively. In this specification, when referring to a specific light-emitting element among the plurality of light-emitting elements 10, a subscript is added after the reference number, such as light-emitting element 10"R," and when either element is acceptable, it is simply referred to as light-emitting element "10." The same applies to other components.

[0016] The light emitting device has a lower electrode 2 arranged on an element substrate 1, an insulating layer 3 covering an edge of the lower electrode 2 and arranged on the element substrate 1, an organic layer 4 including a light emitting layer 42 covering the lower electrode 2 and the insulating layer 3, and an upper electrode 5 covering the organic layer 4. The lower electrode 2 is separated into individual light emitting elements 10 by the insulating layer 3. The insulating layer 3 has an opening 12 above the lower electrode 2.

[0017] An example of the light emitting device 100 will be described in more detail. As the light emitting device 100, an example of a top emission type device in which light is extracted from the upper electrode 5 will be shown. The light emitting device also has an insulating layer 6 that is disposed so as to cover the upper electrode 5 and functions as a protective layer.

[0018] In this embodiment, each subpixel SP of the organic layer 4 emits a respective color of R, G, B light. The light-emitting layer 42 may be colored differently for each pixel according to R, G, B. In this specification, "top" and "bottom" refer to the top and bottom in FIG. 1. The surface of the element substrate 1 on which the lower electrode 2 and other components are arranged is referred to as the main surface or top surface of the element substrate 1. The surface of the lower electrode 2 facing the element substrate 1 is referred to as the bottom surface of the lower electrode 2. Here, FIG. 1 is a cross section passing through the lower electrode 2, the opening 12, and the functional layer 4.

[0019] Here, the lower surface of the lower electrode 2 refers to the surface that contacts the interlayer insulating layer on the uppermost surface of the element substrate 1. Therefore, for example, if a plug or the like for connecting to other wiring is connected to the lower surface of the lower electrode 2, the approximately flat portion excluding that portion is considered to be the lower surface.

[0020] 1, the element substrate 1 may have a driving circuit including a transistor connected to the lower electrode 2, wiring, plugs, and an interlayer insulating layer, and has an interlayer insulating layer on its uppermost surface (the surface in contact with the lower electrode 2). The interlayer insulating layer may contain, for example, an inorganic material such as silicon oxide or silicon nitride, or an organic material such as polyimide or polyacrylic.

[0021] Since organic layers may be deteriorated by moisture, the interlayer insulating layer is preferably formed of an inorganic material from the viewpoint of suppressing moisture penetration. The interlayer insulating layer is also called a planarizing layer because it serves to reduce unevenness on the surface on which the lower electrode 2 is formed.

[0022] For example, as an example of this embodiment, the light emitting device has a lower electrode 2 (first electrode) arranged on the main surface of an element substrate 1, and an insulating layer 3 arranged on the element substrate 1 and the lower electrode 2, with an opening 12 above the lower electrode. The light emitting device also has an organic layer 4 arranged on the lower electrode 2 and the insulating layer 3, with an emitting layer 42, and an upper electrode 5 (second electrode) arranged on the organic layer 4.

[0023] In Fig. 1, the edge of the insulating layer 3 has an inclined portion inclined with respect to the main surface, and the organic layer 4 includes a first compound and a second compound. As will be described in detail later, the highest occupied molecular orbital (HOMO) level of the first compound is higher than the HOMO level of the second compound. Alternatively, the lowest unoccupied molecular orbital (LUMO) level of the first compound is lower than the LUMO level of the second compound. Alternatively, the HOMO level of the first compound may be higher than the HOMO level of the second compound, and the LUMO level of the first compound may be lower than the LUMO level of the second compound.

[0024] The difference between the HOMO level and the LUMO level of the first compound may be smaller than the difference between the HOMO level and the LUMO level of the second compound, and the HOMO level and the LUMO level of the second compound may be located between the HOMO level and the LUMO level of the first compound.

[0025] 3, the organic layer 4 has a first region 4a that contacts the lower electrode 2 at the opening 12 and a second region 4b that is disposed on the inclined portion. The concentration of the first compound in the first region 4a may be higher than the concentration of the first compound in the second region 4b. In this specification, the concentration of compound B in region A refers to the mass percentage of compound B relative to the material contained in region A.

[0026] The lower electrode 2 may be made of a metal material having a reflectance of 80% or more for the emission wavelength of the organic layer 4. For example, metals such as Al and Ag, or alloys of these metals with Si, Cu, Ni, Nd, etc., can be used for the lower electrode 2. Here, the emission wavelength refers to the spectral range of light emitted from the organic layer 4. If the lower electrode 2 has a high reflectance for the emission wavelength of the organic layer 4, the lower electrode 2 may have a stacked structure including a barrier layer. The barrier layer may be made of a metal such as Ti, W, Mo, or Au, or an alloy thereof. The barrier layer may be a metal layer disposed as the uppermost surface of the lower electrode 2.

[0027] The insulating layer 3 is disposed on the element substrate 1 and the lower electrode 2, and has an opening 12 above the lower electrode 2. The insulating layer 3 covers the edge of the lower electrode 2, and may be disposed between the lower electrode 2 and the organic layer 4. In FIG. 1 , the edge of the insulating layer 3 has an inclined portion 31 inclined with respect to the main surface. In the opening 12, the organic layer 4 contacts the lower electrode 2 and the upper electrode 5, and this portion becomes a light-emitting region. In other words, the shape of the light-emitting region in a plan view with respect to the main surface of the element substrate 1 may be a shape defined by the opening 12 in the insulating layer 3.

[0028] For example, in FIG. 1, the light-emitting region of subpixel SPR can be referred to as a first region 1001 where the lower electrode 2R and the organic layer 4 contact within the opening 12. The light-emitting region of subpixel SPG can be referred to as a second region 1002 where the lower electrode 2G and the organic layer 4 contact within the opening 12. A non-light-emitting region 1003 is present between the first region 1001 and the second region 1002. The subpixel SPB has a similar configuration. The insulating layer 3 is not limited to the shape shown in FIG. 1 as long as it has the function of separating the lower electrodes 2 of each light-emitting element 10 and the function of defining the light-emitting region.

[0029] The insulating layer 3 may be formed by, for example, chemical vapor deposition (CVD) or physical vapor deposition (PVD). The insulating layer 3 may be made of an inorganic insulating material such as silicon nitride (SiN), silicon oxynitride (SiON), or silicon oxide (SiO). Alternatively, the insulating layer 3 may be made of at least one of organic materials such as benzocyclobutene resin, acrylate resin, epoxy resin, and imide resin.

[0030] The insulating layer 3 may be a laminated film of these materials or may contain a plurality of materials. The inclination angle of the inclined portion of the insulating layer 3 may be controlled by the conditions of anisotropic etching or isotropic etching.

[0031] The inclination angle of the insulating layer 3 may also be controlled by controlling the inclination angle of the layer immediately below the insulating layer 3. For example, by forming a recess with an inclined side surface in the interlayer insulating layer on the top surface of the element substrate 1 and adjusting the angle of inclination, the inclination angle of the inclined portion of the insulating layer 3 can be adjusted. The insulating layer 3 may have unevenness on its upper surface due to processing such as etching or by stacking layers.

[0032] The organic layer 4 is disposed between the lower electrode 2 and the insulating layer 3 and the upper electrode 5. It may be continuously formed on the upper surface of the element substrate 1 and shared by a plurality of light-emitting elements 10. That is, one organic layer 4 may be shared by a plurality of light-emitting elements. The organic layer 4 may be integrally formed over the entire display region of the organic light-emitting device 100 that displays an image.

[0033] The organic layer 4 has a first region 4a that contacts the lower electrode 2 in the opening 12 and a second region 4b that is disposed on the inclined portion 31. Therefore, the first region 4a in the subpixel SPR is the first region 1001, and the first region 4a in the subpixel SPG is the same as the second region 1002.

[0034] The organic layer 4 may include a charge transport layer 41, an emitting layer 42, and a charge transport layer 43. Appropriate materials can be selected for the organic layer 4 in terms of luminous efficiency, driving life, optical interference, and the like. The charge transport layer may be a hole transport layer or an electron transport layer. For example, when the lower electrode 2 functions as an anode and the upper electrode 5 functions as a cathode, the charge transport layer 41 may be a hole transport layer and the charge transport layer 43 may be an electron transport layer.

[0035] The hole transport layer may function as an electron blocking layer or a hole injection layer, or may have a laminated structure of a hole injection layer, a hole transport layer, an electron blocking layer, etc. The light emitting layer may have a laminated structure of light emitting layers that emit light of different colors, or may be a mixed layer in which light emitting dopants that emit light of different colors are mixed. Furthermore, the electron transport layer may function as a hole blocking layer or an electron injection layer, or may have a laminated structure of an electron injection layer, an electron transport layer, and a hole blocking layer.

[0036] Alternatively, an organic light-emitting device having a tandem structure may have an intermediate layer between a plurality of light-emitting layers, and the intermediate layer is a charge-generating layer. In the tandem structure, a charge-transporting layer such as a hole-transporting layer or an electron-transporting layer may be formed between the charge-generating layer and the light-emitting layer.

[0037] The charge generation layer is a layer that contains an electron donating material and an electron accepting material and generates charges. The electron donating material and the electron accepting material are materials that donate electrons and accept electrons, respectively. This generates positive and negative charges in the charge generation layer, allowing positive or negative charges to be supplied to layers above and below the charge generation layer. The electron donating material may be, for example, an alkali metal such as lithium or cesium.

[0038] The electron donating material may be, for example, lithium fluoride, a lithium complex, cesium carbonate, or a cesium complex. In this case, the electron donating property may be exhibited by being contained together with a reducing material such as aluminum, magnesium, or calcium. The electron accepting material may be, for example, an inorganic material such as molybdenum oxide. The electron accepting material may be, for example, an organic material such as dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile] (HAT-CN). The electron accepting material and the electron donating material may be mixed or layered.

[0039] In this embodiment, the organic layer 4 includes a first compound and a second compound. The concentration of the first compound in the first region 4a of the organic layer 4 is higher than the concentration of the first compound in the second region 4b. The HOMO level of the first compound is higher than the HOMO level of the second compound. Alternatively, the LUMO level of the first compound is lower than the LUMO level of the second compound. As will be described in detail later, this configuration can reduce leakage current between the lower electrode 2 and the upper electrode 5 through the thinned organic layer 4 on the inclined portion 31.

[0040] In the organic layer 4, the light-emitting layer 42 may have a first compound and a second compound. In this case, the first compound may be a dopant material in the light-emitting layer 42, and the second compound may be a host material in the light-emitting layer 42.

[0041] In the organic layer 4, the light-emitting layers 42 are individually disposed in each sub-pixel SP and may have an island shape. By disposing the light-emitting layers 42 individually for each sub-pixel SP, it is possible to emit light of different colors (wavelengths) from each sub-pixel without providing a color filter. Therefore, it is possible to emit light that is not absorbed by a color filter, thereby improving the brightness of the light emitted from the light-emitting device 100.

[0042] An end of the light-emitting layer 42 may be disposed, for example, between adjacent lower electrodes 2 in a plan view with respect to the main surface of the element substrate 1. Specifically, a configuration will be described in which a light-emitting layer 42R (first light-emitting layer) is disposed on a lower electrode 2R, and a light-emitting layer 42G (second light-emitting layer) is disposed on a lower electrode 2G (third electrode) adjacent to the lower electrode 2R. In this case, the insulating layer 3 has an opening 12R (first opening) above the lower electrode 2R and an opening 12G (second opening) above the lower electrode 2G, and the ends of the light-emitting layer 42R and the light-emitting layer 42G are each located between the lower electrode 2R and the lower electrode 2G in the plan view.

[0043] The upper electrode 5 is disposed on the organic layer 4. It is formed continuously on the plurality of lower electrodes 2 with the organic layer 4 sandwiched therebetween, and is shared by the plurality of light-emitting elements 10. Like the organic layer 4, the upper electrode 5 may be formed integrally over the entire display area of ​​the organic light-emitting device 100 where an image is displayed. The upper electrode 5 may be an electrode that transmits at least a portion of the light that reaches the lower surface of the upper electrode 5. The upper electrode may function as a semi-transmissive reflective layer that transmits a portion of the light and reflects the other portion (i.e., semi-transmissive and reflective).

[0044] The upper electrode 5 can be formed from a metal such as magnesium or silver, an alloy mainly composed of magnesium or silver, or an alloy material containing an alkali metal or alkaline earth metal. An oxide conductor or the like may also be used for the upper electrode 5. The upper electrode 5 may also have a laminated structure as long as it has an appropriate transmittance.

[0045] The insulating layer 6 functions as a protective layer and can be made of a material that has low permeability to external oxygen and moisture, such as silicon nitride, silicon oxynitride, aluminum oxide, silicon oxide, and titanium oxide. Silicon nitride and silicon oxynitride can be formed, for example, by CVD. Aluminum oxide, silicon oxide, and titanium oxide can be formed by atomic layer deposition (ALD).

[0046] The combination of the constituent materials and manufacturing method of the insulating layer is not limited to the above examples, but may be selected taking into consideration the thickness of the layer to be formed, the time required for the formation, etc. The insulating layer 6 may have a single layer structure or a multilayer structure as long as it transmits light that has passed through the upper electrode 5 and has sufficient moisture blocking properties.

[0047] Fig. 3 is an enlarged cross-sectional view of a portion of the light-emitting device in the cross-sectional view shown in Fig. 1. Fig. 3 shows an enlarged view of a light-emitting element 10G. As shown in Fig. 3, the concentration of the first compound in the first region 4a of the organic layer 4 is higher than the concentration of the first compound in the second region 4b of the organic layer 4. For example, the concentration of the first compound in the first region 4a of the light-emitting layer 42 may be higher than the concentration of the first compound in the second region 4b of the light-emitting layer 42.

[0048] Here, we will explain the light emitting mechanism of the light emitting element 10 included in the light emitting device 100. When a voltage is applied, the organic light emitting element emits light when both carriers, holes injected from each electrode into the HOMO level of the organic layer and electrons injected into the LUMO level of the organic layer, recombine in the light emitting layer.

[0049] 4 shows the process from carrier injection from each electrode to light emission. For example, the organic layer 4 of the light-emitting element 10 has a hole transport layer, a light-emitting layer, and an electron transport layer in this order from the lower electrode 2 toward the upper electrode 5. In this case, holes are injected from the lower electrode 2 into the hole transport layer and then into the light-emitting layer. Electrons are injected from the upper electrode 5 into the electron transport layer and then into the light-emitting layer.

[0050] The light-emitting layer may include, for example, a first compound and a second compound. Figure 4 shows an example in which the HOMO level of the first compound is higher than that of the second compound, and the LUMO level of the first compound is lower than that of the second compound. The first compound may be, for example, a light-emitting material, and the second compound may be a host.

[0051] After carriers (electrons or holes) are injected into the light-emitting layer, each carrier moves from the second compound to the first compound, where they recombine on the molecules of the first compound, emitting light. During this process, carriers move by hopping conduction between randomly arranged molecules between and within each layer.

[0052] Next, the mechanism of reducing the leakage current between the lower electrode 2 and the upper electrode 5 will be described using an example in which the light-emitting layer 42 contains a first compound and a second compound. When the concentration of the first compound in the light-emitting layer is increased, the intermolecular distance of the first compound is short, allowing carriers to move directly between the molecules of the first compound. This allows for efficient carrier movement within the first compound.

[0053] 5 is a conceptual diagram showing the movement of electrons in the light-emitting layer 42 when the concentration of the first compound in the light-emitting layer 42 is increased. The electrons that move from the second compound to the first compound are efficiently hopped between the LUMO levels of the first compound.

[0054] 6 shows an image of the movement of holes in the light-emitting layer 42 when the concentration of the first compound in the light-emitting layer 42 is increased. Holes that move from the second compound to the first compound are efficiently hopped between the HOMO levels of the first compound.

[0055] On the other hand, if the concentration of the first compound in the light-emitting layer is reduced, the intermolecular distance of the first compound becomes longer, and carriers cannot move directly between the molecules of the first compound. Therefore, in order to move between the molecules of the first compound, the carriers must first move to the energy level of the second compound.

[0056] The first compound acts as a trap level for carriers due to a large difference in energy levels between the HOMO level and / or LUMO level of the first compound and the second compound. In this case, the carriers cannot easily move due to the large difference in energy levels, resulting in low carrier mobility.

[0057] Figure 7 shows an image of electron movement within the light-emitting layer 42 when the concentration of the first compound within the light-emitting layer 42 is reduced. Electrons that move from the second compound to the first compound move to the LUMO level of the first compound, which acts as a trap level, and then move to the LUMO level of the second compound. The large difference between the LUMO levels of the first compound and the second compound creates a large energy barrier for electron movement, reducing mobility. This makes it difficult for current to flow from the lower electrode 2 to the upper electrode 5 via the light-emitting layer 42.

[0058] FIG. 8 shows an image of hole movement within the light-emitting layer 42 when the concentration of the first compound in the light-emitting layer 42 is reduced. Holes that move from the second compound to the first compound move to the HOMO level of the first compound, which acts as a trap level, and then move to the HOMO level of the second compound. If the difference between the HOMO levels of the first compound and the second compound is large, this creates a large energy barrier for hole movement, reducing mobility. This makes it difficult for current to flow from the lower electrode 2 to the upper electrode 5 through the light-emitting layer 42.

[0059] For the above reasons, in the light-emitting device, the concentration of the first compound in the second region 4b, where the thickness of the organic layer 4 is small and leakage current between the upper and lower electrodes is likely to occur, is made lower than the concentration of the first compound in the first region 4a. This reduces the mobility of holes and / or electrons, increasing the electrical resistance of the organic layer 4. This reduces leakage current between the lower electrode 2 and the upper electrode 5.

[0060] The concentration of the first compound in the second region 42b of the light-emitting layer 42 can be set to, for example, 50% or less of the concentration of the first compound in the first region 42a of the light-emitting layer 42.

[0061] In order to suppress the leakage current between the lower electrode 2 and the upper electrode 5 through the inclined portion 31, it is also possible to prevent the organic layer 4 from becoming thin and to increase the film thickness of the organic layer 4 on the inclined portion 31. For example, the film thickness of the organic layer 4 formed on the inclined portion 31 can be increased by using a deposition mask with a wide opening or adjusting the deposition direction from the deposition source.

[0062] However, when the light-emitting device is configured such that the light-emitting layer 42 is independent for each subpixel SP, using a mask with a wide opening makes it difficult to finely separate the light-emitting layers. Therefore, it may be difficult to achieve both high definition and reduced leakage current between light-emitting elements in a light-emitting device.

[0063] On the other hand, in the light-emitting device of this embodiment, the concentration of the first compound in the organic layer 4 above the sloped portion 31 is lower than the concentration of the first compound in the portion in contact with the lower electrode 2. In addition, the HOMO level of the first compound is higher than the HOMO level of the second compound, or the LUMO level of the first compound is lower than the LUMO level of the second compound. Therefore, the resistance of the organic layer 4 to charges in the second region 4b is higher than the resistance in the first region 4a, and therefore the leakage current between the lower electrode 2 and the upper electrode 5 on the sloped portion 31 can be reduced.

[0064] Furthermore, there is no need to enlarge the openings in the deposition mask when forming the light-emitting layer or change the deposition angle to thicken the organic layer, which allows for the deposition of a fine light-emitting layer group, thereby achieving both a reduction in leakage current between the lower electrode 2 and the upper electrode 5 and high-definition light-emitting devices.

[0065] 3, the first region 4a has a central portion 4a1 and a peripheral portion 4a2. The central portion refers to a region whose distance from the geometric center of gravity O of the opening 12 is one-third or less of the distance from the geometric center of gravity O to the edge of the opening 12. The peripheral portion refers to a region whose distance from the edge of the opening 12 is one-tenth or less of the distance from the edge of the opening 12 to the geometric center of gravity O of the opening 12. Here, the geometric center of gravity O of the opening 12 refers to the geometric center of gravity of the shape of the opening 12 when viewed in plan with respect to the main surface of the substrate.

[0066] The difference between the concentration Ca of the first compound in the central portion 4a1 of the first region and the concentration Cb of the first compound in the peripheral portion 4a2 is smaller than the difference between the concentration Cb of the first compound in the peripheral portion 4a2 and the concentration Cc of the first compound in the sloped portion of the insulating layer 3. In the light-emitting device of this embodiment, the concentration Cc of the first compound in the sloped portion of the insulating layer 3 is lower than the concentrations Ca and Cb of the first compound in the light-emitting region. Therefore, it is possible to reduce leakage current between the lower electrode 2 and the upper electrode 5 via the thinned organic layer 4 on the sloped portion 31.

[0067] Furthermore, the difference between the concentration Ca of the first compound in the central portion 4a1 of the first region and the concentration Cb of the first compound in the peripheral portion 4a2 is smaller than the difference between the concentration Cb of the first compound in the peripheral portion 4a2 and the concentration Cc of the first compound in the sloped portion of the insulating layer 3. Therefore, the difference in concentration of the first compound between the central portion 4a1 and the peripheral portion 4a2 in the light-emitting region can be reduced, thereby reducing variations in brightness in the light-emitting region.

[0068] Although an example in which the HOMO level of the first compound is higher than that of the second compound and the LUMO level of the first compound is lower than that of the second compound has been described above, this embodiment is not limited thereto. For example, if the HOMO level of the first compound is higher than that of the second compound, the configuration of this embodiment can reduce the mobility of holes in the organic layer 4. Furthermore, if the LUMO level of the first compound is lower than that of the second compound, the mobility of electrons in the organic layer 4 can be reduced. Therefore, the resistance in the thickness direction of the thinned portion of the organic layer 4 can be increased, thereby reducing the leakage current between the lower electrode 2 and the upper electrode 5.

[0069] Furthermore, the difference between the HOMO level and the LUMO level of the first compound may be smaller than the difference between the HOMO level and the LUMO level of the second compound. This configuration can achieve the above-mentioned effects. Furthermore, it is preferable that the HOMO level and the LUMO level of the second compound are located between the HOMO level and the LUMO level of the first compound. This configuration can reduce the mobility of both electrons and holes, thereby favorably reducing the leakage current between the bottom electrode 2 and the upper electrode 5.

[0070] An example of a manufacturing method for the light emitting device 100 of this embodiment will be described. First, a metal layer is formed on a substrate 1, and a desired region of the metal layer is etched using a mask pattern or the like to form a lower electrode 2. Next, an insulating layer 3 is formed so as to cover the edge of the lower electrode 2. In this embodiment, the insulating layer 3 is formed of, for example, silicon oxide.

[0071] After forming the insulating layer 3, desired regions of the insulating layer 3 are etched using a mask pattern or the like to form openings 12. In this embodiment, the pixel arrangement may be, for example, a delta arrangement. As shown in FIG. 2, the pixels may be arranged in a delta arrangement in which each subpixel is hexagonal.

[0072] Next, the organic layer 4 is formed. The organic layer may have a structure including a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, and an electron injection layer in this order. First, a hole injection layer is formed on the device substrate 1. Next, a hole transport layer, an electron blocking layer, and a light-emitting layer are formed. The light-emitting layer may be a mixed layer of a host material and a light-emitting dopant. The weight ratio of the light-emitting dopant (weight percentage of the dopant material relative to the host material) can be adjusted to, for example, 3%.

[0073] After forming the light-emitting layer, an electron transport layer and an electron injection layer may be formed. After forming the organic layer 4, the upper electrode 5 is formed. After forming the upper electrode 5, a sealing layer may be formed by CVD, and a silicon nitride film may be formed as the insulating layer 6.

[0074] Here, a method for forming the light-emitting layer 42 will be described. FIG. 9 is a diagram illustrating a method for manufacturing a light-emitting layer by vacuum evaporation. FIG. 10 is an enlarged view of the film-forming portion of FIG. 9. FIG. 9 shows an example in which three evaporation sources 413-1 to 413-3 are used. The number of evaporation sources is not limited to three, and four, five, six, and more may be added. Although not shown, each layer up to the electron blocking layer is disposed on the substrate 1.

[0075] In order to form the light-emitting layer 42, a mask 401 is placed on the element substrate 1. The mask 401 has openings 403, which are aligned with positions on the substrate 1 where the light-emitting layer 42 is to be formed. An enlarged view of the opening pattern of the circular openings 403 is shown in FIG.

[0076] During deposition, the directionality of deposition can be controlled by setting the inclination of the deposition source using an angle limiting plate 405 having an opening 407. For example, a deposition source for a first light-emitting dopant is disposed in deposition source 413-1, a deposition source for a host material is disposed in deposition source 413-2, and a deposition source for a second light-emitting dopant is disposed in deposition source 413-3.

[0077] Here, a shadow of each material from the evaporation source is generated between the element substrate 1 and the mask 401. The shadow region is generated due to differences in the shape of the mask, the distance between the evaporation source and the substrate, and the angle of the evaporation source relative to the substrate.

[0078] One way to lower the doping concentration in the second region 4b is to use a method in which materials from the deposition source are not deposited on the pixel edges by utilizing shadows that flow around the mask openings. This method allows the width of the second region 4b to be adjusted by changing the mask thickness, the shape of the mask edges, and the deposition angle.

[0079] 10 is a diagram showing a deposition area 4131 when the light-emitting layer 42 is formed using the mask 401 and the deposition source 413. When the light-emitting layer 42 is formed using the deposition source 413-1 and the deposition source 413-3, the dopant is heavily doped in the areas where the deposition area 4131-1 and the deposition area 4131-3 overlap, and the dopant is lightly doped in the areas where they do not overlap.

[0080] By arranging the members as described above, the doping amount of the dopant is suppressed in the shadow region, and the dopant concentration is reduced in the second region 42b of the light-emitting layer 42. The concentration of compound 1 in the second region 42b of the light-emitting layer 42 may be 50% or less of the concentration of compound 1 in the first region 4a of the light-emitting layer 42.

[0081] [Second embodiment] An example of a light emitting device 200 of this embodiment will be described with reference to Fig. 12. In the following explanation, differences from the first embodiment will be mainly described, and explanations of the same configurations, materials, properties, functions, effects, etc. as the first embodiment will be omitted.

[0082] The light emitting device 200 according to this embodiment includes, in addition to the components of the light emitting device 100 according to the first embodiment, an insulating layer 7 that functions as a planarization layer, and a microlens array MLA disposed thereon. The microlens array MLA includes a first microlens 8R corresponding to the first light emitting element 10R, a second microlens 8G corresponding to the second light emitting element 10G, and a third microlens 8B corresponding to the third light emitting element 10B. Each microlens 8 is disposed so as to overlap with the center of the light emitting region of the corresponding light emitting element 10 in a planar view with respect to the main surface of the element substrate 1. Note that, although the light emitting region of the light emitting element 10 is defined by an opening in the insulating layer 3, the center of the light emitting region may be the center of gravity of the opening in the insulating layer 3.

[0083] The microlenses 8 included in the microlens array MLA have a light-collecting effect. The microlenses 8 have the function of collecting light incident from the insulating layer 6 side and emitting it from the surface opposite to the insulating layer 6.

[0084] Conventionally known microlenses can be used as the microlenses 8 constituting the microlens array MLA. The material of the microlenses 8 may be resin. The microlens array MLA can be formed, for example, by forming a film (photoresist film) from a material for forming the microlenses 8, and exposing and developing the photoresist film using a mask having a continuous change in tone.

[0085] Such a mask can be a gray mask or an area-modulating mask. Furthermore, the lens shape can be adjusted by etching back the microlenses 8 formed by the exposure and development process. The shape of the microlenses 8 may be any shape that can refract the emitted light, and may be spherical or aspherical, and the cross-sectional shape may be asymmetric.

[0086] The light exit surface side of the microlens 8, in other words, the side opposite to the insulating layer 6, is preferably filled with a material having a lower refractive index than the microlens 8, typically air. This increases the light-collecting effect of the microlens 8. The insulating layer 6 may also have a convex portion on its upper surface that protrudes away from the element substrate 1. The convex portion of the insulating layer 6 also has a light-collecting effect similar to that of the microlens 8.

[0087] [Third embodiment] An example of a light emitting device 300 of this embodiment will be described with reference to Fig. 13. In the following description, differences from the first embodiment will be mainly described, and descriptions of the same configurations, materials, properties, functions, effects, etc. as the first embodiment will be omitted.

[0088] 13 shows an enlarged view of the opening pattern of hexagonal openings 433 in mask 431. In the first embodiment, mask 401 having circular openings 403 is used, but here mask 431 having hexagonal openings 433 is used. The shape of the openings is not limited to a hexagon, and may be another polygon.

[0089] An example of a pixel arrangement of the light-emitting device of this embodiment will be described with reference to Figures 14(a) and 14(b). In this embodiment, the pixel arrangement is a stripe arrangement. As shown in Figure 14(a), the pixels may be arranged in a stripe arrangement in which each sub-pixel is rectangular. Figure 14(b) shows an enlarged view of the opening pattern of rectangular openings 443 in the mask 441 used. In the first embodiment, a mask 401 having circular openings 403 was used, but here a mask 441 having rectangular openings 443 is used.

[0090] An example of a pixel arrangement of the light-emitting device of this embodiment will be described with reference to Figures 15(a) and 15(b). In this embodiment, the pixel arrangement is a pentile arrangement. As shown in Figure 15(a), the pixels may be a pentile arrangement in which each pixel is rectangular. Figure 15(b) shows an enlarged view of the opening pattern of rectangular openings 453 in the mask 451 used. While the first embodiment used a mask 401 with circular openings 403, this embodiment uses a mask 451 with rectangular openings 453.

[0091] [Fourth embodiment] Next, an example of an organic light-emitting element that can be used in the light-emitting device according to any one of Embodiments 1 to 3 will be described. The organic layer 4 of the organic light-emitting element according to this embodiment may include, in addition to the light-emitting layer, a hole injection layer, a hole transport layer, an electron blocking layer, a hole / exciton blocking layer, an electron transport layer, an electron injection layer, etc. The light-emitting layer may be a single layer or a laminate consisting of multiple layers. When the light-emitting layer includes multiple layers, a charge generation layer may be provided between the light-emitting layers. The charge generation layer may be composed of a compound having a lower LUMO than the hole transport layer, and the LUMO of the charge generation layer may be lower than the HOMO of the hole transport layer. Here, the molecular orbital energy of the organic compound layer may be the molecular orbital energy of the organic compound having the largest weight ratio in the organic compound layer.

[0092] The substrate of the element substrate 1 may be made of quartz, glass, silicon wafer, resin, metal, or the like. Furthermore, the substrate may be provided with switching elements such as transistors and wiring, with an insulating layer thereon. When a silicon wafer is used as the substrate, the active layer, source region, and drain region of the transistor are formed within the substrate. Furthermore, this is preferable because it allows for densely arranged transistors.

[0093] The interlayer insulating layer may be made of any material as long as it can form a contact hole to connect the first electrode to the wiring and can ensure insulation from wiring that is not connected. For example, resins such as polyimide, silicon oxide, silicon nitride, etc. can be used.

[0094] The electrode may be formed of one material alone or two or more materials in combination, and the anode may be formed of one layer or multiple layers.

[0095] The insulating layer 3, which serves as a pixel separation layer, may be formed of, for example, a silicon nitride (SiN) film, a silicon oxynitride (SiON) film, or a silicon oxide (SiO) film formed using a chemical vapor deposition method (CVD method).

[0096] On the other hand, it is preferable to adjust the taper angle of the end of the insulating layer 3 and the film thickness of the pixel separation layer to such an extent that voids are not formed in the insulating layer 6 (protective layer) formed on top of the insulating layer 3. Since voids are not formed in the insulating layer 6, which is a protective layer, it is possible to reduce the occurrence of defects in the insulating layer 6. Since the occurrence of defects in the protective layer is reduced, it is possible to reduce deterioration in reliability such as the occurrence of dark spots and poor conduction of the second electrode.

[0097] Charge leakage to adjacent pixels can be effectively suppressed by adjusting the taper angle of the edge of the insulating layer 3. For example, as mentioned above, it has been found that sufficient reduction can be achieved if the taper angle is in the range of 60 degrees to 90 degrees. The thickness of the insulating layer 3 is preferably in the range of 10 nm to 150 nm.

[0098] The organic layer 4 may include layers other than the charge transport layer 41 and the light-emitting layer 42. The layers included in the organic layer 4 may be called hole injection layers, hole transport layers, electron blocking layers, light-emitting layers, hole blocking layers, electron transport layers, or electron injection layers depending on the functions of the layers. The organic layer 4 is mainly composed of organic compounds, but may also contain inorganic atoms or compounds. For example, the organic layer 4 may contain copper, lithium, magnesium, aluminum, iridium, platinum, molybdenum, zinc, or the like.

[0099] When the device has multiple light-emitting layers, a charge generation section may be provided between the first and second light-emitting layers. The charge generation section may have an organic compound with a lowest unoccupied molecular orbital energy (LUMO) of -5.0 eV or less. The same applies when the charge generation section is provided between the second and third light-emitting layers.

[0100] An insulating layer 6 may be provided on the second electrode 5 as a protective layer. For example, a passivation film such as silicon nitride may be provided on the second electrode 5 as the insulating layer 6 to reduce the penetration of water and the like into the organic layer 4. For example, after forming the second electrode 5, the second electrode 5 may be transferred to another chamber without breaking the vacuum, and a silicon nitride film having a thickness of 2 μm may be formed by CVD to serve as a protective layer. After the CVD film formation, the insulating layer 6 may be provided using atomic layer deposition (ALD). The material of the film formed by ALD is not limited, and may be silicon nitride, silicon oxide, aluminum oxide, or the like. Silicon nitride may be further formed on the film formed by ALD by CVD. The film formed by ALD may have a thickness smaller than that of the film formed by CVD. Specifically, the thickness may be 50% or less, or even 10% or less.

[0101] An insulating layer 7 may be disposed on the insulating layer 6, functioning as a planarizing layer to reduce unevenness on the upper surface of the insulating layer 6. The insulating layer may be composed of an organic compound, and may be either a low molecular weight or a high molecular weight, but a high molecular weight is preferred. The insulating layer 7 may also be composed of an inorganic material, and may contain silicon oxide, silicon nitride, or the like. When the light-emitting device has a color filter, the insulating layer 7 may be disposed above and below the color filter, and the constituent materials thereof may be the same or different. Specific examples of the insulating layer 7 include polyvinyl carbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenolic resin, epoxy resin, silicone resin, and urea resin.

[0102] The light emitting device may have an optical member such as a microlens 8 on its light emitting side. The microlens 8 may be made of acrylic resin, epoxy resin, or the like. The microlens 8 may be intended to increase the amount of light extracted from the light emitting device and control the direction of the extracted light. The microlens 8 may have a hemispherical shape. When the microlens 8 has a hemispherical shape, among the tangents to the hemisphere, there is a tangent that is parallel to the insulating layer, and the point of contact between the tangent and the hemisphere is the vertex of the microlens 8.

[0103] The vertex of the microlens 8 can be determined in the same way for any cross-sectional view. That is, among the tangents to the semicircle of the microlens 8 in the cross-sectional view, there is a tangent that is parallel to the insulating layer, and the point of contact between this tangent and the semicircle is the vertex of the microlens.

[0104] It is also possible to define the midpoint of the microlens 8. In the cross section of the microlens 8, a line segment is imagined from the point where an arc shape ends to the point where another arc shape ends, and the midpoint of this line segment can be called the midpoint of the microlens 8. The cross section for determining the vertex and midpoint may be a cross section perpendicular to the insulating layer.

[0105] The microlens 8 has a first surface having a convex portion and a second surface opposite the first surface. The second surface is preferably disposed closer to the organic layer than the first surface. To achieve this configuration, the microlens 8 must be formed on the organic light-emitting element 10. In the case of an organic layer, it is preferable to avoid processes that result in high temperatures during the manufacturing process. Furthermore, when a configuration is adopted in which the second surface is disposed closer to the organic layer than the first surface, it is preferable that the glass transition temperatures of all of the organic compounds that make up the organic layer are 100°C or higher, and more preferably 130°C or higher.

[0106] An opposing substrate may be provided on the insulating layer 7 or the microlenses 8. The opposing substrate is called an opposing substrate because it is provided at a position corresponding to the aforementioned substrate. The constituent material of the opposing substrate may be the same as that of the aforementioned substrate. When the aforementioned substrate is defined as a first substrate, the opposing substrate may be a second substrate.

[0107] The light-emitting device may have a pixel circuit connected to the light-emitting element. The pixel circuit may be an active matrix type that controls the emission of the first light-emitting element and the second light-emitting element independently. The active matrix type circuit may be voltage-programmed or current-programmed. The drive circuit has a pixel circuit for each pixel. The pixel circuit may have a light-emitting element, a transistor that controls the emission brightness of the light-emitting element, a transistor that controls the emission timing, a capacitor that holds the gate voltage of the transistor that controls the emission brightness, and a transistor for connecting to GND without going through the light-emitting element.

[0108] The light-emitting device may have a display region and a peripheral region arranged around the display region, the display region having a pixel circuit and the peripheral region having a display control circuit, and the mobility of a transistor constituting the pixel circuit may be lower than the mobility of a transistor constituting the display control circuit.

[0109] The slope of the current-voltage characteristics of the transistors that make up the pixel circuit may be smaller than the slope of the current-voltage characteristics of the transistors that make up the display control circuit. The slope of the current-voltage characteristics can be measured using the so-called Vg-Ig characteristics.

[0110] The transistors that make up the pixel circuit are transistors connected to light-emitting elements such as the first light-emitting element.

[0111] As described in the above embodiments, the light emitting device has a plurality of pixels. Each pixel has sub-pixels SP that emit different colors. The sub-pixels SP may emit different colors, for example, RGB.

[0112] In a pixel, a region also called a pixel aperture emits light. This region is the same as the first region 1001 or the second region 1002. In the light-emitting device according to at least one of the first to third embodiments, the distance between subpixels (from the center to the center of adjacent subpixels) is, for example, 6.4 μm or less.

[0113] The pixels may be arranged in a known manner in a plan view. For example, they may be in a stripe arrangement, a delta arrangement, a honeycomb arrangement, a pentile arrangement, or a Bayer arrangement. The shape of the subpixels in a plan view may be any known shape. For example, they may be rectangular, quadrilaterals such as diamonds, or hexagons. Of course, a shape that is close to a rectangle, rather than an exact shape, is included in the rectangle. The shape of the subpixels and the pixel arrangement may be used in combination.

[0114] The light emitting device according to any one of the first to third embodiments can be used as a component of a display device, etc. For example, it can be used as a light emitting device having a white light source and a color filter.

[0115] The display device may be an image information processing device that has an image input unit that inputs image information from an area CCD, a linear CCD, a memory card, etc., has an information processing unit that processes the input information, and displays the input image on the display unit. The display unit may have the light-emitting device described in any of the first to third embodiments.

[0116] Furthermore, the display unit of an imaging device or an inkjet printer may include any of the display devices according to the first to third embodiments. The display unit may have a touch panel function. The driving method for this touch panel function may be an infrared method, a capacitance method, a resistive film method, or an electromagnetic induction method, and is not particularly limited. The display device may also be used in the display unit of a multifunction printer.

[0117] Next, a display device according to the present embodiment will be described with reference to the drawings.

[0118] 16 is a cross-sectional view showing an example of a light-emitting device having an organic light-emitting element and a transistor connected to the organic light-emitting element. The transistor is an example of an active element. Here, a thin-film transistor (TFT) is shown as an example of the transistor, but a MOSFET using a semiconductor substrate can also be used. By using a MOSFET, the transistors in each pixel can be arranged in a smaller area in accordance with the above-described embodiment.

[0119] FIG. 16(a) shows an example of a pixel, which is a component of the light-emitting device according to this embodiment. The pixel has subpixels SP. The subpixels are divided into SPR, SPG, and SPB based on their light emission. The emitted color may be distinguished by the wavelength of light emitted from the light-emitting layer, or the light emitted from the subpixels may be selectively transmitted or color-converted using a color filter or the like. In each subpixel SP, the light-emitting device has a lower electrode 2 on an element substrate 1, an insulating layer 3 covering the edge of the lower electrode 2, an organic layer 4 covering the lower electrode 2 and the insulating layer 3, a second electrode 5, and an insulating layer 6.

[0120] A transistor and a capacitor may be disposed below or inside the element substrate 1. The transistor and the lower electrode 2 may be electrically connected via a contact hole or the like (not shown).

[0121] The insulating layer 3 is also called a bank or a pixel separation film. It covers the edge of the lower electrode 2 and is disposed to surround the lower electrode 2. The portion where the insulating layer 3 is not disposed contacts the organic layer 4 and becomes the light-emitting region.

[0122] The organic layer 4 includes a hole injection layer 45 , a hole transport layer 41 , a first light-emitting layer 42 A, a second light-emitting layer 42 B, and an electron transport layer 43 .

[0123] The second electrode 5 may be a transparent electrode or a semi-transparent electrode.

[0124] The insulating layer 6 reduces the penetration of moisture into the organic layer 4. Although the insulating layer 6 is illustrated as being one layer, it may be multiple layers, each of which may be an inorganic compound layer or an organic compound layer.

[0125] 17 is a schematic diagram showing an example of a display device as an example of a light-emitting device. The display device 1010 may have a touch panel 1013, a display panel 1015, a frame 1016, a circuit board 1017, and a battery 1018 between an upper cover 1011 and a lower cover 1019. The touch panel 1013 and the display panel 1015 are connected by flexible printed circuits FPCs 1012 and 1014.

[0126] The display panel 1015 includes at least one organic light-emitting device according to Embodiments 1 to 3. Transistors are printed on a circuit board 1017. The battery 1018 may not be provided if the display device is not a portable device, or may be provided in a different location if the display device is a portable device.

[0127] The display device according to the present embodiment may be used as a display unit of a mobile terminal. In this case, the display device may have both a display function and an operation function. Examples of the mobile terminal include a mobile phone such as a smartphone, a tablet, and a head-mounted display.

[0128] The display device according to this embodiment may be used as a display unit of an imaging device having an optical unit with a plurality of lenses and an imaging element that receives light that has passed through the optical unit. The imaging device may have a display unit that displays information acquired by the imaging element. The display unit may be a display unit exposed to the outside of the imaging device or a display unit disposed within a viewfinder. The imaging device may be a digital camera or a digital video camera.

[0129] 18(a) is a schematic diagram showing an example of an imaging device as an application example of the light-emitting device according to this embodiment. The imaging device 1100 may have a viewfinder 1101, a rear display 1102, an operation unit 1103, and a housing 1104. The viewfinder 1101 may have the organic light-emitting device according to at least one of embodiments 1 to 3 as a display. In this case, the organic light-emitting device may display not only an image to be captured, but also environmental information, imaging instructions, and the like. The environmental information may include the intensity of external light, the direction of external light, the speed at which the subject is moving, the possibility that the subject will be blocked by an obstruction, and the like.

[0130] Since the optimum timing for capturing an image is very short, it is better to display information as soon as possible. Therefore, it is preferable to use an organic light-emitting device according to any one of the first to third embodiments using an organic light-emitting element. This is because organic light-emitting elements have a fast response speed. Display devices using organic light-emitting elements require high display speed, and in this respect, the light-emitting device according to any one of the first to third embodiments can be used more preferably than liquid crystal display devices.

[0131] The imaging device 1100 has an optical section (not shown). The optical section has multiple lenses, which form an image on an imaging element housed in a housing 1104. The focus of the multiple lenses can be adjusted by adjusting their relative positions. This operation can also be performed automatically. The imaging device may also be called a photoelectric conversion device. Instead of sequentially capturing images, the photoelectric conversion device can include an imaging method that detects the difference from the previous image, or a method of cutting out an image from a constantly recorded image, etc.

[0132] 18(b) is a schematic diagram showing an example of an electronic device according to this embodiment. The electronic device 1200 has a display unit 1201, an operation unit 1202, and a housing 1203. The housing 1203 may include a circuit, a printed circuit board having the circuit, a battery, and a communication unit.

[0133] The display unit 1201 may have an organic light-emitting device according to at least one of embodiments 1 to 3. The operation unit 1202 may be a button or a touch panel type reaction unit. The operation unit may be a biometric recognition unit that recognizes a fingerprint to unlock the device, etc. An electronic device having a communication unit may also be called a communication device. The electronic device may further have a camera function by including a lens and an image sensor. An image captured by the camera function is displayed on the display unit. Examples of the electronic device include a smartphone, a laptop computer, etc.

[0134] Fig. 19 is a schematic diagram showing an example of a display device according to this embodiment. Fig. 19(a) shows a display device such as a television monitor or a PC monitor. The display device 1300 has a frame 1301 and a display unit 1302 surrounded by the frame 1301. The light-emitting device according to at least one of embodiments 1 to 3 may be used for the display unit 1302.

[0135] The display device 1300 further includes a frame 1301 and a base 1303 that supports a display unit 1302. The base 1303 is not limited to the form shown in Fig. 19(a). For example, the bottom side of the frame 1301 may also serve as the base.

[0136] The frame 1301 and the display unit 1302 may be curved. The radius of curvature may be 5000 mm or more and 6000 mm or less.

[0137] FIG. 19(b) is a schematic diagram illustrating another example of a display device according to this embodiment. The display device 1310 in FIG. 19(b) is configured to be bendable, and is a so-called foldable display device. The display device 1310 has a first display unit 1311, a second display unit 1312, a housing 1313, and a bending point 1314. The first display unit 1311 and the second display unit 1312 may include an organic light-emitting device according to at least one of embodiments 1 to 3. The first display unit 1311 and the second display unit 1312 may be a single, seamless display unit. The first display unit 1311 and the second display unit 1312 can be separated by the bending point. The first display unit 1311 and the second display unit 1312 may display different images, or the first and second display units may display a single image.

[0138] An application example of a display device having the organic light-emitting device according to any one of the first to third embodiments will be described with reference to Fig. 20. The display device can be applied to a system that can be attached as a wearable device, such as smart glasses, an HMD, or a smart contact lens. The image capture device and the display device used in such an application example can be an image capture device capable of photoelectrically converting visible light, and a display device capable of emitting visible light.

[0139] 20(a) illustrates glasses 1600 (smart glasses) according to one application example. An imaging device 1602 such as a CMOS sensor or a SPAD is provided on the front side of a lens 1601 of the glasses 1600. In addition, a display device 1604 having a light-emitting device according to at least one of the above-described first to third embodiments is provided on the back side of the lens 1601.

[0140] The glasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the image capture device 1602 and the display device 1604. The control device 1603 also controls the operations of the image capture device 1602 and the display device. The lens 1601 is formed with an optical system for focusing light onto the image capture device 1602.

[0141] 20(b) illustrates glasses 1610 (smart glasses) according to one application example. The glasses 1610 include a control device 1612. The control device 1612 is equipped with an image capturing device corresponding to the image capturing device 1602 and a display device 1614 corresponding to the display device 1604. An optical system for projecting light emitted by the display device 1614 in the control device 1612 is formed in the lens 1611, and an image is projected onto the lens 1611. The control device 1612 functions as a power source that supplies power to the image capturing device and the display device 1614, and also controls the operations of the image capturing device and the display device 1614.

[0142] The control device may have a gaze detection unit that detects the gaze of the wearer. The gaze detection may use infrared rays. The infrared light emitting unit emits infrared light toward the eyeball of the user who is gazing at the displayed image. An imaging unit having a light receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining an image of the eyeball. By having a reduction means that reduces light from the infrared light emitting unit to the display unit in a planar view, degradation of image quality is reduced.

[0143] The gaze of the user relative to the displayed image is detected from an image of the eyeball obtained by capturing infrared light. Any known method can be used for gaze detection using an image of the eyeball. One example is a gaze detection method based on the Purkinje image formed by reflection of irradiated light on the cornea.

[0144] More specifically, gaze detection processing is performed based on the pupil-corneal reflex method, which calculates a gaze vector representing the direction (rotation angle) of the eyeball based on the pupil image and Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze.

[0145] The glasses 1610 according to the embodiment may have an imaging device with a light receiving element, and may control the image displayed on the display device based on information on the user's line of sight from the imaging device.

[0146] Specifically, display device 1614 determines a first display area on which the user gazes and a second display area other than the first display area based on the line-of-sight information. The first and second display areas may be determined by a control device of glasses 1610, or may be determined by an external control device and received. In the display areas of display device 1614, the display resolution of the first display area may be controlled to be higher than the display resolution of the second display area. In other words, the resolution of the second display area may be set lower than that of the first display area.

[0147] The display area includes a first display area and a second display area different from the first display area, and a high-priority area is determined from the first display area and the second display area based on line-of-sight information. The first and second viewing areas may be determined by a control device of the display device, or may be determined by an external control device and received. The resolution of the high-priority area may be controlled to be higher than the resolution of areas other than the high-priority area. In other words, the resolution of an area with a relatively low priority may be lowered.

[0148] Note that AI may be used to determine the first display area and areas with high priority. The AI ​​may be a model configured to estimate the angle of gaze and the distance to an object in the line of sight from an image of the eyeball, using as training data an image of the eyeball and the actual direction in which the eyeball in the image was looking. The AI ​​program may be included in the display device, the imaging device, or an external device. If included in an external device, it is transmitted to the display device via communication.

[0149] When display control is performed based on visual recognition detection, the smart glasses can be preferably applied to smart glasses that further include an imaging device for capturing images of the outside world. The smart glasses can display captured external information in real time.

[0150] In this way, by applying the organic light-emitting device according to at least one of Embodiments 1 to 3 to various devices according to this embodiment, it is possible to reduce the size of the device or to achieve higher resolution for the same size. Also, it is possible to provide a device with reduced variations during manufacturing.

[0151] The present disclosure includes, for example, the following configurations.

[0152] Figure 21 shows an image forming apparatus according to this embodiment. Figure 21(a) is a schematic diagram of an image forming apparatus 1136 according to this embodiment. The image forming apparatus has a photosensitive member, an exposure light source, a developing unit, a charging unit, a transfer unit, a transport roller, and a fixing unit.

[0153] Light 1129 is irradiated from an exposure light source 1128, and an electrostatic latent image is formed on the surface of a photosensitive member 1127. This exposure light source has an organic light-emitting element according to the present invention. A developing unit 1131 has toner, etc. A charging unit 1130 charges the photosensitive member. A transfer device 1132 transfers the developed image to a recording medium 1134. A transport unit 1133 transports the recording medium 1134. The recording medium 1134 is, for example, paper. A fixing unit 1135 fixes the image formed on the recording medium.

[0154] 21(b) and 21(c) are schematic diagrams showing an exposure light source 1128 in which multiple light-emitting units 1138 are arranged on a long substrate. Direction 1137 is parallel to the axis of the photoconductor and represents the row direction in which the organic light-emitting elements are arranged. This row direction is the same as the axis direction about which the photoconductor 1127 rotates. This direction can also be called the long axis direction of the photoconductor.

[0155] Figure 21(b) shows a configuration in which the light-emitting units are arranged along the longitudinal axis of the photoconductor. Figure 21(c) shows a different configuration from (b), in which the light-emitting units are arranged alternately in the column direction in the first and second columns. The first and second columns are arranged at different positions in the row direction.

[0156] The first column has a plurality of light-emitting units 1138 arranged at intervals. The second column has light-emitting units at positions corresponding to the intervals between the light-emitting units in the first column. That is, the plurality of light-emitting units are also arranged at intervals in the row direction. The light-emitting device according to at least one of embodiments 1 to 3 can be used as the light-emitting units 1138.

[0157] The arrangement in FIG. 21(c) can also be described as a grid arrangement, a houndstooth arrangement, or a checkerboard pattern.

[0158] 22 is a schematic diagram of an automobile, which is an example of a moving body according to this embodiment. The automobile 1500 includes a steering wheel 1504 for controlling the direction of movement of the moving body, and a display unit 1505 mounted on the body 1503 for displaying a map, the position of the moving body, turning directions, etc. The display unit 1505 may include an organic light-emitting device according to at least one of embodiments 1 to 3.

[0159] Although an automobile has been described as an example here, the moving body according to this embodiment is not limited to an automobile. The moving body according to this embodiment includes one or both of a driving force generating unit that generates a driving force mainly used to move the moving body, and a rotating body mainly used to move the moving body. The driving force generating unit may be an engine, a motor, etc. The rotating body may be a tire, a wheel, a ship's screw, a propeller of an aircraft, etc. Specifically, the moving body may be a bicycle, a car, a train, a ship, an airplane, a drone, etc.

[0160] The moving object may have a vehicle body and a lighting device provided on the vehicle body or a display unit provided on the vehicle body. The lighting device may emit light to indicate the vehicle body's position. The lighting device may have the organic light-emitting element according to this embodiment. Furthermore, the display unit may have the organic light-emitting element according to the above embodiment.

[0161] The present disclosure includes, for example, the following configurations.

[0162] (Configuration 1) a first electrode disposed on a major surface of the element substrate; an insulating layer disposed on the element substrate and the first electrode, the insulating layer having an opening above the first electrode; an organic layer disposed on the first electrode and the insulating layer and having a light-emitting layer; a second electrode disposed on the organic layer; and an end of the insulating layer has an inclined portion inclined with respect to the main surface in a cross section passing through the first electrode, the opening, and the organic layer; the organic layer comprises a first compound and a second compound; the highest occupied molecular orbital (HOMO) level of the first compound is higher than the HOMO level of the second compound; the organic layer has a first region in contact with the first electrode in the opening and a second region disposed on the inclined portion; a concentration of the first compound in the first region is greater than a concentration of the first compound in the second region; Light-emitting device.

[0163] (Configuration 2) The light emitting device of configuration 1, wherein the film thickness of the first region in a direction perpendicular to a surface of the first electrode that contacts the first region is greater than the film thickness of the second region in a direction perpendicular to a surface of the inclined portion that contacts the second region.

[0164] (Configuration 3) 3. The light-emitting device of Configuration 1 or 2, wherein the organic layer comprises a charge transport layer between the first electrode and the light-emitting layer.

[0165] (Configuration 4) 4. The light-emitting device according to any one of Configurations 1 to 3, wherein the organic layer has an island-like shape in a plan view relative to the main surface.

[0166] (Configuration 5) a third electrode adjacent to the first electrode on the main surface; a second light-emitting layer disposed on the third electrode; and the insulating layer has a second opening above the third electrode; The light-emitting device according to any one of Configurations 1 to 4, wherein the end of the light-emitting layer is located between the first electrode and the third electrode in a plan view relative to the main surface.

[0167] (Configuration 6) 6. The light-emitting device according to any one of configurations 1 to 5, wherein the light-emitting layer comprises the first compound and the second compound.

[0168] (Configuration 7) The light-emitting device according to any one of configurations 1 to 6, wherein the light-emitting layer comprises the first compound and the second compound, and the lowest excited singlet energy of the first compound is lower than the lowest excited singlet energy of the second compound.

[0169] (Configuration 8) The light-emitting device according to any one of configurations 1 to 6, wherein the light-emitting layer comprises the first compound and the second compound, and the lowest excited triplet energy of the first compound is lower than the lowest excited triplet energy of the second compound.

[0170] (Configuration 9) 9. The light-emitting device of any one of configurations 1 to 8, wherein the light-emitting layer comprises the first compound and the second compound, and a lowest unoccupied molecular orbital (LUMO) level of the first compound is lower than a LUMO level of the second compound.

[0171] (Configuration 10) 10. The light emitting device of any one of configurations 1 to 9, wherein the concentration of the first compound in the second region is 50% or less of the concentration of the first compound in the first region.

[0172] (Configuration 11) a first electrode disposed on a major surface of the element substrate; an insulating layer disposed on the element substrate and the first electrode, the insulating layer having an opening above the first electrode; an organic layer disposed on the first electrode and the insulating layer and having a light-emitting layer; a second electrode disposed on the organic layer; and an end of the insulating layer has an inclined portion inclined with respect to the main surface in a cross section passing through the first electrode, the opening, and the organic layer; the organic layer comprises a first compound and a second compound; the LUMO level of the first compound is lower than the LUMO level of the second compound; the organic layer has a first region in contact with the first electrode in the opening and a second region disposed on the inclined portion; a concentration of the first compound in the first region is greater than a concentration of the first compound in the second region; Light-emitting device.

[0173] (Configuration 12) 12. The light emitting device of claim 11, wherein the thickness of the first region in a direction perpendicular to a surface of the first electrode that contacts the first region is greater than the thickness of the second region in a direction perpendicular to a surface of the inclined portion that contacts the second region.

[0174] (Configuration 13) 13. The light-emitting device of claim 11 or 12, wherein the organic layer comprises a charge transport layer between the first electrode and the light-emitting layer.

[0175] (Configuration 14) 14. The light-emitting device according to any one of Configurations 11 to 13, wherein the organic layer has an island shape in a plan view relative to the main surface.

[0176] (Configuration 15) a third electrode adjacent to the first electrode on the main surface; a second light-emitting layer disposed on the third electrode; and the insulating layer has a second opening above the third electrode; The light-emitting device according to any one of Structures 11 to 14, wherein an end portion of the organic layer is located between the first electrode and the third electrode in a plan view relative to the main surface.

[0177] (Configuration 16) 16. The light-emitting device of any one of configurations 11 to 15, wherein the light-emitting layer comprises the first compound and the second compound.

[0178] (Configuration 17) 17. The light-emitting device of any one of configurations 11 to 16, wherein the light-emitting layer comprises the first compound and the second compound, and the lowest excited singlet energy of the first compound is lower than the lowest excited singlet energy of the second compound.

[0179] (Configuration 18) 17. The light-emitting device of any one of configurations 11 to 16, wherein the light-emitting layer comprises the first compound and the second compound, and the lowest excited triplet energy of the first compound is lower than the lowest excited triplet energy of the second compound.

[0180] (Configuration 19) 19. The light emitting device of any one of configurations 11 to 18, wherein the concentration of the first compound in the second region is 50% or less of the concentration of the first compound in the first region.

[0181] (Configuration 20) 20. A display device comprising: a light-emitting device according to any one of configurations 1 to 19; and a transistor connected to the first electrode of the light-emitting device.

[0182] (Configuration 21) an optical unit having a plurality of lenses, an image pickup element that receives light that has passed through the optical unit, and a display unit that displays an image picked up by the image pickup element; 20. A photoelectric conversion device, wherein the display unit has a light-emitting device according to any one of structures 1 to 19.

[0183] (Configuration 22) 20. An electronic device comprising: a display unit having a light-emitting device according to any one of configurations 1 to 19; a housing in which the display unit is provided; and a communication unit provided in the housing for communicating with an external device.

[0184] (Configuration 23) a lens in which an imaging device and a display unit are arranged, and a control device; the display unit is provided with a light-emitting device according to any one of configurations 1 to 19; The control device controls the operations of the imaging device and the display unit.

[0185] (Configuration 24) an exposure light source having the light-emitting device of any one of configurations 1 to 19; a photosensitive member that is irradiated with light from the exposure light source.

[0186] (Configuration 25) A vehicle body and a display unit mounted on the vehicle body, 19. A mobile object, wherein the display unit has the light-emitting device of any one of configurations 1 to 19. [Explanation of symbols]

[0187] 1. Element substrate 2 Lower electrode 3. Insulation layer 4 Organic layer 5 Upper electrode 100 Light-emitting device

Claims

1. a first electrode disposed on a major surface of the element substrate; an insulating layer disposed on the element substrate and the first electrode, the insulating layer having an opening above the first electrode; an organic layer disposed on the first electrode and the insulating layer and having a light-emitting layer; a second electrode disposed on the organic layer; and an end of the insulating layer has an inclined portion inclined with respect to the main surface in a cross section passing through the first electrode, the opening, and the organic layer; the organic layer comprises a first compound and a second compound; the highest occupied molecular orbital (HOMO) level of the first compound is higher than the HOMO level of the second compound; the organic layer has a first region in contact with the first electrode in the opening and a second region disposed on the inclined portion; a concentration of the first compound in the first region is greater than a concentration of the first compound in the second region; Light-emitting device.

2. 2. The light-emitting device according to claim 1, wherein the thickness of the first region in a direction perpendicular to the surface of the first electrode that contacts the first region is greater than the thickness of the second region in a direction perpendicular to the surface of the inclined portion that contacts the second region.

3. The light-emitting device according to claim 1 , wherein the organic layer comprises a charge transport layer between the first electrode and the light-emitting layer.

4. The light-emitting device according to claim 1 , wherein the organic layer has an island-like shape in a plan view relative to the main surface.

5. a third electrode adjacent to the first electrode on the main surface; a second light-emitting layer disposed on the third electrode; and the insulating layer has a second opening above the third electrode; The light emitting device according to claim 1 , wherein an end portion of the light emitting layer is located between the first electrode and the third electrode in a plan view relative to the main surface.

6. The light-emitting device of claim 1 , wherein the light-emitting layer comprises the first compound and the second compound.

7. 2. The light-emitting device according to claim 1, wherein the light-emitting layer comprises the first compound and the second compound, and the lowest excited singlet energy of the first compound is lower than the lowest excited singlet energy of the second compound.

8. 2. The light-emitting device according to claim 1, wherein the light-emitting layer comprises the first compound and the second compound, and the lowest excited triplet energy of the first compound is lower than the lowest excited triplet energy of the second compound.

9. 2. The light emitting device of claim 1, wherein the light emitting layer comprises the first compound and the second compound, and a lowest unoccupied molecular orbital (LUMO) level of the first compound is lower than a LUMO level of the second compound.

10. 2. The light emitting device according to claim 1, wherein the concentration of the first compound in the second region is 50% or less of the concentration of the first compound in the first region.

11. a first electrode disposed on a major surface of the element substrate; an insulating layer disposed on the element substrate and the first electrode, the insulating layer having an opening above the first electrode; an organic layer disposed on the first electrode and the insulating layer and having a light-emitting layer; a second electrode disposed on the organic layer; and an end of the insulating layer has an inclined portion inclined with respect to the main surface in a cross section passing through the first electrode, the opening, and the organic layer; the organic layer comprises a first compound and a second compound; a LUMO level of the first compound is lower than a LUMO level of the second compound; the organic layer has a first region in contact with the first electrode in the opening and a second region disposed on the inclined portion; a concentration of the first compound in the first region is greater than a concentration of the first compound in the second region; Light-emitting device.

12. The light-emitting device according to claim 11 , wherein the thickness of the first region in a direction perpendicular to the surface of the first electrode that contacts the first region is greater than the thickness of the second region in a direction perpendicular to the surface of the inclined portion that contacts the second region.

13. 12. The light-emitting device of claim 11, wherein the organic layer comprises a charge transport layer between the first electrode and the light-emitting layer.

14. The light-emitting device according to claim 11 , wherein the organic layer has an island-like shape in a plan view relative to the main surface.

15. a third electrode adjacent to the first electrode on the main surface; a second light-emitting layer disposed on the third electrode; and the insulating layer has a second opening above the third electrode; The light-emitting device according to claim 11 , wherein an end portion of the organic layer is located between the first electrode and the third electrode in a plan view relative to the main surface.

16. The light emitting device of claim 11 , wherein the light emitting layer comprises the first compound and the second compound.

17. The light-emitting device according to claim 11 , wherein the light-emitting layer comprises the first compound and the second compound, and the lowest excited singlet energy of the first compound is lower than the lowest excited singlet energy of the second compound.

18. The light-emitting device according to claim 11 , wherein the light-emitting layer comprises the first compound and the second compound, and the lowest excited triplet energy of the first compound is lower than the lowest excited triplet energy of the second compound.

19. The light emitting device according to claim 11 , wherein the concentration of the first compound in the second region is 50% or less of the concentration of the first compound in the first region.

20. 20. A display device comprising: the light-emitting device according to claim 1; and a transistor connected to the first electrode of the light-emitting device.

21. an optical unit having a plurality of lenses, an image pickup element that receives light that has passed through the optical unit, and a display unit that displays an image picked up by the image pickup element; 20. A photoelectric conversion device, comprising: a display portion comprising the light-emitting device according to claim 1;

22. 20. An electronic device comprising: a display unit having the light-emitting device according to claim 1; a housing in which the display unit is provided; and a communication unit provided in the housing for communicating with an external device.

23. a lens in which an imaging device and a display unit are arranged, and a control device; The display unit is provided with a light-emitting device according to any one of claims 1 to 19, The control device controls the operations of the imaging device and the display unit.

24. an exposure light source having the light emitting device according to any one of claims 1 to 19; a photosensitive member that is irradiated with light from the exposure light source.

25. A vehicle body and a display unit mounted on the vehicle body, A moving object, wherein the display unit comprises the light emitting device according to claim 1 .

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