Organic light-emitting element, and display apparatus, imaging apparatus, electronic device, illumination apparatus, moving object, and exposure light source including the same

Abstract

To provide an organic light-emitting element which has a low drive voltage and durability that is less likely to decrease.SOLUTION: There is provided, an organic light-emitting element including an anode 2, a first light-emitting layer 4a, a functional layer 5 in contact with the first light-emitting layer 4a, and a cathode 7 in this order. In the organic light-emitting element, energy levels of a first host material and a first dopant material that form the first light-emitting layer 4a and an organic material that forms the functional layer satisfy specific relations.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an organic light-emitting device which is one of light-emitting devices, and to equipment and devices using the device.

Background Art

[0002] In recent years, research and development of a full-color light-emitting array using an organic light-emitting device (hereinafter sometimes referred to as an "organic electroluminescence device" or an "organic EL device") has been vigorously promoted. In general, an organic light-emitting device is formed by sequentially forming a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode on an anode. Further, a hole blocking layer may be provided on the light-emitting layer side of the electron transport layer, and an electron injection layer may be provided on the cathode side of the electron transport layer. In addition, when manufacturing a full-color light-emitting array, there are a method of separately coating the light-emitting layer for each pixel (element), and a method using a white organic light-emitting device in which the light-emitting layer emits white light and color filters of red, green, and blue are separately coated for each pixel. Regarding white organic light-emitting devices, three color light-emitting materials corresponding to color filters, namely red, green, and blue, are often used. Patent Document 1 discloses a white organic light-emitting device in which a two-color light-emitting layer containing a red light-emitting material and a green light-emitting material in one light-emitting layer and a two-layer light-emitting layer of an electron-trapping blue light-emitting layer are laminated adjacent to each other, and the host material of the light-emitting layer is made the same to reduce the driving voltage of the white EL device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The white organic light-emitting device disclosed in Patent Document 1 has an excellent emission balance, but has a problem that the driving voltage of the device becomes high because it has a hole blocking layer in contact with an electron-trapping blue light-emitting layer. In addition, hole accumulation easily occurs at the interface between the electron-trapping blue light-emitting layer and the hole blocking layer during energization, and there is a problem that the durability degradation of the device easily progresses. The present invention has been made to solve the above problems, and provides an organic light-emitting device with a low driving voltage of the device and a low progress of durability degradation of the device, and a device and an apparatus using the device.

Means for Solving the Problems

[0005] A first aspect of the present invention is an organic light-emitting device having an anode, a first light-emitting layer, a functional layer in contact with the first light-emitting layer, and a cathode in this order, the first light-emitting layer includes a first host material and a first dopant material, when the energy levels of the LUMO of the first host material and the first dopant material are LUMO h1 and LUMO d1 and the energy levels of the HOMO of the first host material, the first dopant material, and the organic material constituting the functional layer are HOMO h1 and HOMO d1 and HOMO FL it is characterized by satisfying the following formulas [1] to [3]. LUMO h1 > LUMO d1 [1] HOMO h1 > HOMO d1 [2] HOMO FL > HOMO h1 [3] A second aspect of the present invention is a display device having a plurality of pixels, wherein at least one of the pixels has the first organic light-emitting device of the present invention and an active element connected to the organic light-emitting device. A third aspect of the present invention has an optical unit having a plurality of lenses, an imaging element that receives light that has passed through the optical unit, and a display unit, The display unit is a display unit that displays information acquired by the image sensor, and the imaging device is characterized by having the second display device of the present invention. The fourth aspect of the present invention comprises a housing, a communication unit for communicating with the outside, and a display unit, The aforementioned display unit is an electronic device characterized by having the second display device of the present invention. The fifth aspect of the present invention is an illumination device having a light source and a light diffusion unit or optical filter, The aforementioned light source is a lighting device characterized by having the first organic light-emitting element of the present invention. The sixth aspect of the present invention comprises an aircraft body and a lighting fixture provided on the aircraft body, The aforementioned light fixture is a mobile body characterized by having the first organic light-emitting element of the present invention. The seventh aspect of the present invention is an exposure light source for an electrophotographic image forming apparatus, characterized by having the first organic light-emitting element of the present invention. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic cross-sectional diagram in the thickness direction of an organic light-emitting element according to one embodiment of the present invention, and an energy diagram schematically showing the energy levels around the first light-emitting layer. [Figure 2] This is a schematic cross-sectional view in the thickness direction of an organic light-emitting element according to another embodiment of the present invention, and an energy diagram schematically showing the energy levels around the first and second light-emitting layers. [Figure 3] (a) A schematic diagram of an image forming apparatus according to one embodiment of the present invention. (b) and (c) Schematic diagrams showing a configuration in which multiple light-emitting units of an exposure light source are arranged on a long substrate. [Figure 4] (a) A schematic cross-sectional view showing an example of a pixel of a display device according to one embodiment of the present invention. (b) A schematic cross-sectional view showing an example of a display device using an organic light-emitting element according to one embodiment of the present invention. [Figure 5] This is a schematic diagram illustrating an example of a display device according to one embodiment of the present invention. [Figure 6](a) A schematic diagram showing an example of a display device according to one embodiment of the present invention. (b) A schematic diagram showing an example of a foldable display device. [Figure 7] (a) A schematic diagram showing an example of an imaging device according to one embodiment of the present invention. (b) A schematic diagram showing an example of an electronic device according to one embodiment of the present invention. [Figure 8] This is a schematic diagram showing an example of a lighting device according to one embodiment of the present invention. [Figure 9] This is a schematic diagram showing an example of an automobile equipped with a vehicle lighting device according to one embodiment of the present invention. [Figure 10] (a) A schematic diagram showing an example of a wearable device according to one embodiment of the present invention. (b) A schematic diagram showing an example of a wearable device according to one embodiment of the present invention, which includes an imaging device. [Modes for carrying out the invention]

[0007] The organic light-emitting element of the present invention is configured such that the energy levels of the light-emitting layer, functional layer, and electron transport layer in the organic light-emitting layer placed between the anode and cathode have a specific relationship, resulting in an organic light-emitting element with a low driving voltage and less deterioration of durability. The configuration [1] and preferred configurations [2] to [6] of the present invention will be described below. Configuration [1]: An organic light-emitting element having an anode, a first light-emitting layer, a functional layer in contact with the first light-emitting layer, and a cathode in this order, wherein the first light-emitting layer includes a first host material (hereinafter referred to as "first host") and a first dopant material (hereinafter referred to as "first dopant"). Furthermore, the LUMO energy levels of the first host and first dopant are set to LUMO h1 , LUMO d1 The energy levels of the HOMO of the organic materials constituting the first host, first dopant, and functional layer are defined as HOMO h1 , HOMO d1 , HOMO FL When this is the case, the following equations [1] to [3] are satisfied.

[0008] Furthermore, HOMO is the highest occupied orbital, and LUMO is the lowest unoccupied orbital. The energy level of HOMO is also called the "HOMO level," and the energy level of LUMO is also called the "LUMO level." The HOMO level and LUMO level are relative to the vacuum level and take negative values ​​for typical molecules. In this specification, when comparing the HOMO level and LUMO level using inequality signs, a magnitude relationship rather than absolute values ​​is used. In addition, the methods for measuring the HOMO level and LUMO level values ​​used in this invention and the results of measuring several materials are shown in the examples described later.

[0009] LUMO h1 >LUMO d1 [1] HOMO h1 >HOMO d1 [2] HOMO FL >HOMO h1 [3]

[0010] This will be explained using Figure 1. Figure 1(a) is a schematic cross-sectional view in the thickness (stacked) direction of one embodiment of the organic light-emitting element of the present invention. In the figure, 1 is the substrate, 2 is the anode, 3 is the hole transport layer, 4a is the first light-emitting layer, 5 is the functional layer, 6 is the electron transport layer, and 7 is the cathode. In the present invention, the first light-emitting layer 4a is a layer of organic compound provided between the anode 2 and the cathode 7 that has a light-emitting function. The first host contained in the first light-emitting layer 4a refers to the main component material among the materials contained in the first light-emitting layer 4a. More specifically, the first host refers to the material contained in the first light-emitting layer 4a whose content in the first light-emitting layer 4a exceeds 50% by mass.

[0011] On the other hand, the first dopant refers to the material contained in the first light-emitting layer 4a that is not the main component. More specifically, the first dopant refers to the material contained in the first light-emitting layer 4a that accounts for less than 50% by mass of the first light-emitting layer 4a.

[0012] Figure 1(b) is an energy diagram schematically showing the energy levels around the first light-emitting layer 4a that constitutes the organic light-emitting device in Figure 1(a). When electrons are injected from the functional layer 5 into the first light-emitting layer 4a that satisfies equation [1], the LUMO with a lower energy level d1 Electrons enter the LUMO, and because the dopant concentration is low, conduction does not occur, and the electrons enter the LUMO. d1 You get trapped.

[0013] Furthermore, when holes are injected from the hole transport layer 3 into the first light-emitting layer 4a that satisfies equation [2], a HOMO with a high energy level is formed. h1 A hole enters, and HOMO moves toward functional layer 5. h1 It conducts through the current, recombining with electrons along the way and emitting light. In other words, the first light-emitting layer 4a that satisfies equations [1] and [2] is electron-trapping and hole-transporting.

[0014] In this invention, a functional layer 5 is arranged on the cathode 7 side of the first light-emitting layer 4a, in contact with the first light-emitting layer 4a. The first host of the functional layer 5 and the first light-emitting layer 4a satisfies formula [3], and HOMO h1 Holes that conduct and fail to recombine with electrons are not blocked by the HOMO level of functional layer 5. FL This will lead to joining.

[0015] Therefore, in the organic light-emitting element of the present invention, hole accumulation does not occur in the first light-emitting layer 4a, the driving voltage of the element is low, and the durability degradation due to hole accumulation of the element is less likely to progress.

[0016] In configuration [1], it is preferable that formulas [1] and [2] satisfy formula [4] below, and / or that formula [3] satisfies formula [3-1] and further formula [3-2] below. |LUMO h1 -LUMO d1 |>|HOMO h1 -HOMO d1 | [4] HOMO FL -HOMO h1 ≥0.05[eV] [3-1] HOMO FL -HOMO h1≥0.15[eV] [3-2]

[0017] Configuration [2]: The first light-emitting layer has a second light-emitting layer adjacent to the anode side, and the second light-emitting layer contains a second host material (hereinafter referred to as "second host") and a second dopant material (hereinafter referred to as "second host"). Furthermore, the HOMO levels of the second dopant and second host of the second light-emitting layer are set to HOMO d2 , HOMO h2 When this is the case, the following equation [5] is satisfied. HOMO d2 >HOMO h2 [5]

[0018] This will be explained using Figure 2. Figure 2(a) is a schematic cross-sectional view in the thickness direction of another embodiment of the organic light-emitting element of the present invention. In this embodiment, a second light-emitting layer 4b is provided on the anode 2 side of the first light-emitting layer 4a, in contact with the first light-emitting layer 4a. The second light-emitting layer 4b also has a light-emitting function similar to the first light-emitting layer 4a, and consists of a second host as the main component and a second dopant.

[0019] Figure 2(b) is an energy diagram schematically showing the energy levels around the first light-emitting layer 4a and the second light-emitting layer 4b that constitute the organic light-emitting device of this embodiment. Similar to the explanation in Figure 1, when electrons are injected from the functional layer 5 into the first light-emitting layer 4a that satisfies equation [1], the LUMO with a lower energy level d1 Electrons enter the LUMO, and because the concentration of the first dopant is low, it does not conduct, and the electrons enter the LUMO. d1 You get trapped.

[0020] If the concentration of the first dopant is sufficiently low, LUMO d1 Electrons that cannot enter the high-energy LUMO h1 Entering the second light-emitting layer 4b, LUMO h1 It conducts. Therefore, in this form, because the concentration of the first dopant is sufficiently low, some of the electrons are in the LUMO. d1 It is trapped there, and some of it passes through the first light-emitting layer 4a and is injected into the second light-emitting layer 4b, where HOMO d2 It recombines with trapped holes and emits light in the second light-emitting layer 4b.

[0021] Furthermore, when holes are injected from the hole transport layer 3 into the second light-emitting layer 4b that satisfies equation [5], a HOMO with a high energy level is formed. d2 A hole enters, and because the concentration of the second dopant is low, it does not conduct and the HOMO d2 It gets trapped. Here too, if the concentration of the second dopant is sufficiently low, HOMO d2 Holes that cannot enter the HOMO are in the lower energy levels. h2 It enters the first light-emitting layer 4a and conducts towards it.

[0022] Therefore, because the concentration of the second dopant is sufficiently low, some of the holes become HOMO d2 The holes are trapped in the HOMO, and some pass through the second light-emitting layer 4b and are injected into the first light-emitting layer 4a. Since the first light-emitting layer 4a satisfies equation [2], the holes are HOMO h1 Conducting, LUMO d1 The electrons trapped there recombine and emit light in the first light-emitting layer 4a. Here too, the concentration of the second dopant needs to be sufficiently low, preferably 0.1% to 5% by mass.

[0023] In this invention, the functional layer 5 is in contact with the cathode side of the first light-emitting layer 4a. The functional layer 5 and the first host of the first light-emitting layer 4a satisfy equation [3], and HOMO h1 Holes that conduct and fail to recombine with electrons are not blocked by the HOMO level of functional layer 5 here either. FL This will lead to joining. Therefore, in this embodiment, the organic light-emitting element does not accumulate holes in the first light-emitting layer 4a, the driving voltage of the element is low, and the durability degradation of the element is less likely to progress.

[0024] In configuration [2], it is preferable that the above formula [5] satisfies the following [5-1]. HOMO d2 -HOMO h2 >0.4[eV] [5-1]

[0025] As described above, the second light-emitting layer 4b in this embodiment traps some holes and emits light in the second light-emitting layer 4b by recombining them with electrons that have passed through the first light-emitting layer 4a. If the trap depth is insufficient, the probability of trapping holes decreases. The probability of trapping holes can be increased by increasing the concentration of the second dopant, but increasing the dopant concentration in the light-emitting layer reduces the luminescence brightness due to a phenomenon called concentration quenching. Therefore, in this embodiment, it is preferable that the hole trap depth is sufficient to satisfy the above formula [5-1]. A sufficient hole trap depth is preferable because it limits the number of holes injected into the first light-emitting layer 4a, making durability degradation less likely to occur. As shown in formula [5-1], a trap depth greater than 0.40 eV is preferred, and more preferably 0.45 eV to 0.50 eV.

[0026] Configuration [3]: The first host and the second host are the same. In the present invention, as illustrated in Figure 2(a), when there is a first light-emitting layer 4a and a second light-emitting layer 4b, it is preferable that the first host of the first light-emitting layer 4a and the second host of the second light-emitting layer 4b are made of the same material. Furthermore, it is preferable that the first light-emitting layer 4a and the second light-emitting layer 4b are formed adjacent to each other, and that no other layer, such as a charge barrier layer, is inserted between the light-emitting layers 4a and 4b. This is in consideration of the driving voltage of the device, and aims to eliminate the electrical resistance of the charge barrier layer and to prevent the voltage from rising due to holes and electrons in the light-emitting layers 4a and 4b moving to the energy levels of other layers. In the present invention, as described above, among the materials contained in the light-emitting layers 4a and 4b, the material whose content in the light-emitting layers 4a and 4b exceeds 50 mass% is called the host material, but from the viewpoint of reducing the voltage, a higher concentration of the host material is better. Therefore, it is preferably 90 mass% or more, more preferably 95 mass% or more.

[0027] The host material is an aromatic hydrocarbon compound which may have an alkyl group having 1 to 12 carbon atoms, and it is preferable that the aromatic hydrocarbon compound contains a structure selected from benzene, naphthalene, fluorene, benzofluorene, phenanthrene, chrysene, triphenylene, pyrene, fluorantene, and benzofluorantene.

[0028] The organic light-emitting element according to this embodiment uses a host material with a wide band gap that can emit blue light-emitting dopant material (hereinafter referred to as "blue dopant"), so a structure with high exciton energy during charge recombination and high intramolecular bond energy is preferred.

[0029] The benzene, naphthalene, fluorene, benzofluorene, phenanthrene, chrysene, triphenylene, pyrene, fluorantene, and benzofluorantene listed above are preferred because they consist of up to two rings in which benzene rings are linearly condensed, resulting in high intramolecular bond energy.

[0030] Preferred specific examples of host materials are shown in EM1 to EM37 below. Hereafter, when specific examples of materials are shown in the present invention, they are preferred examples, but the invention is not necessarily limited to those examples shown.

[0031] [ka]

[0032] Configuration [4]: ​​The second light-emitting layer contains the third dopant material (hereinafter referred to as the "third dopant"). The first dopant is a blue dopant, the second dopant is a red light-emitting dopant material (hereinafter referred to as the "red dopant"), and the third dopant is a green light-emitting dopant material (hereinafter referred to as the "green dopant"). Furthermore, the HOMO levels of the third dopant and the second host are set to HOMO d3 , HOMO h2 When this is the case, the following equation [6] is satisfied. HOMO d3 >HOMO h2 [6]

[0033] In the present invention, as illustrated in Figure 2(a), when there is a first light-emitting layer 4a and a second light-emitting layer 4b, it is preferable that the first light-emitting layer 4a is a blue light-emitting layer. In full-color light-emitting arrays using organic light-emitting elements, three light-emitting materials of red, green, and blue are often used, but the blue light-emitting layer has the problem that the durability of the element tends to deteriorate due to hole accumulation.

[0034] As described above, the first light-emitting layer 4a according to the present invention is electron-trapping and hole-transporting, so hole accumulation does not occur in the light-emitting layer 4a, nor does successful accumulation occur at the interface with the functional layer 5. Therefore, it is preferable to use a blue light-emitting layer for the first light-emitting layer 4a as it is less prone to durability degradation. Specific examples of materials that can be suitably used as light-emitting dopant materials for the blue light-emitting layer are shown below in BD1 to BD31.

[0035] [ka]

[0036] In this embodiment, if the first light-emitting layer 4a is a blue light-emitting layer and the second light-emitting layer 4b is a two-color light-emitting layer of red and green (hereinafter referred to as the "red-green light-emitting layer"), a white organic light-emitting element can be obtained. In this case, a two-color light-emitting layer of red and green can be obtained by including a red dopant and a green dopant in the second light-emitting layer 4b.

[0037] In this embodiment, the second light-emitting layer 4b satisfies formula [5] above, allowing the red dopant to trap holes. However, it is preferable that it also satisfies formula [6] above, allowing the green dopant to trap holes. These red and green light-emitting dopant materials exhibit less deterioration in durability compared to the blue light-emitting layer, even when trapping holes. Specific examples of red dopants are shown in RD1 to RD23 below, and specific examples of green dopants are shown in GD1 to GD32 below.

[0038] [ka]

[0039] [ka]

[0040] In this invention, among the light components extracted from an organic light-emitting element, the light-emitting component with a maximum emission wavelength of 570 nm to 650 nm is defined as red, and the light-emitting material that emits this red light is defined as a red dopant. Similarly, the light-emitting component with a maximum emission wavelength of 490 nm to 540 nm is defined as green, and the light-emitting material that emits this green light is defined as a green dopant. Similarly, the light-emitting component with a maximum emission wavelength of 430 nm to 480 nm is defined as blue, and the light-emitting material that emits this blue light is defined as a blue dopant.

[0041] Composition [5]: The organic material constituting the functional layer consists solely of hydrocarbons. Since holes accumulate in the functional layer 5 according to the present invention, it is preferable that the molecular structure be able to withstand the generation of excessive radical cations, and it is preferable that it consists only of hydrocarbons with high chemical stability. By consisting only of hydrocarbons, the functional layer 5 consists only of compounds that do not have bonds with low bonding stability in their molecular structure, so that the driving degradation of the compounds is less likely to occur when the device is driven, and the lifespan of the organic light-emitting element is long, which is preferable. In molecular structures, bonds with low bonding stability refer to bonds like amino groups, which have relatively low bond energy and are therefore unstable.

[0042] In compounds A-1, A-2, and B-1 shown below, the bonds with low bond stability are the bond connecting the carbazole ring and the phenylene group, and the bond connecting the amino group and the phenyl group (nitrogen-carbon bond). Bonds connecting carbon to carbon, such as in compound B-1, have higher bond stability. The calculation method used was b3-lyp / def2-SV(P).

[0043] [ka]

[0044] Based on the above results, it is preferable that the material constituting the functional layer 5 according to the present invention is composed solely of hydrocarbons. Specifically, benzene, naphthalene, fluorene, benzofluorene, phenanthrene, chrysene, triphenylene, pyrene, fluorantene, and benzofluorantene are preferred because they consist of up to two rings in which benzene rings are linearly condensed, resulting in high intramolecular bond energy. Specific examples of materials that can be suitably used as functional layer 5 are shown below in FL1 to FL24.

[0045] [ka]

[0046] Configuration [6]: On the cathode side of the functional layer, in contact with the functional layer, there is an electron transport layer made of an organic material, and the HOMO levels of the functional layer and the organic material constituting the electron transport layer are set to HOMO FL , HOMO ETL When this is the case, the following equation [7] is satisfied. HOMO FL >HOMO ETL [7]

[0047] By satisfying the above equation [7], electrons are injected from the electron transport layer 6 to the functional layer 5 without barriers. Since holes are also injected from the first light-emitting layer 4a to the functional layer 5 without barriers, hole accumulation occurs in the functional layer 5, and holes and electrons that could not be recombined in the first light-emitting layer 4a are recombined in the functional layer 5. Therefore, the accumulation of holes in the functional layer 5 prevents the light-emitting layer 4a from degrading in durability due to hole accumulation.

[0048] The material used for the electron transport layer 6 can be arbitrarily selected from those capable of transporting electrons injected from the cathode 7 to the first light-emitting layer 4a, and is selected considering the balance with the hole mobility of the hole-transporting material. The same material can be used for the hole-blocking layer and the electron injection layer. Examples of materials with electron transport properties include oxadiazole derivatives, oxazole derivatives, pyrazine derivatives, triazole derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, and phenanthroline derivatives. Specific examples of materials that can be suitably used in the electron transport layer 6 are shown below in ET1 to ET14.

[0049] [ka]

[0050] (Other configurations of organic light-emitting diodes) Other configurations of the organic light-emitting device of the present invention will be described. <Circuit board> As shown in Figures 1(a) and 2(a), the organic light-emitting element of the present invention may have a substrate 1, which may be a silicon substrate, a glass substrate, or a resin substrate. If it is a silicon substrate, it can be used as a microdisplay device by forming transistors on the silicon substrate itself. If it is a glass substrate, it may be used as a display device by providing a TFT. The resin substrate may also be called a flexible substrate. In the case of a flexible substrate, it may be a foldable or rollable display device. Transmissive or opaque is not a concern as long as it does not obstruct the light emission direction of the light-emitting device.

[0051] <Electrode> The organic light-emitting element of the present invention has an anode 2 and a cathode 7, where the anode 2 is a reflective electrode and the cathode 7 is a transmissive electrode. Alternatively, either the anode 2 or the cathode 7 may be a transmissive electrode, or the anode 2 may be a transmissive electrode and the cathode 7 may be a reflective electrode.

[0052] The reflective electrode is preferably made of a metallic material with a reflectivity of 80% or more. Specifically, metals such as Al and Ag, or alloys to which Si, Cu, Ni, Nd, Ti, etc. are added, can be used. Suitable alloys include AgMg, AlCu, TiN, etc. Reflectivity refers to the reflectivity at the emission wavelength emitted from the light-emitting layer. The reflective electrode may also have a barrier layer on the surface on the light extraction side. Preferred materials for the barrier layer are metals such as Ti, W, Mo, and Au, or their alloys. The term "alloy" may include the aforementioned alloys.

[0053] The permeable electrode may be a conductive metal oxide such as ITO or IZO, or a semi-permeable metal layer. When the permeable electrode is used as the cathode, it may be formed from an alloy mainly composed of magnesium or silver, or an alloy material containing alkali metals or alkaline earth metals. The permeable electrode may also be in a laminated configuration if it has a desirable transmittance. The electrodes can be formed by sputtering, vacuum deposition, or other methods.

[0054] <Organic compound layer> In addition to the configurations shown in Figures 1(a) and 2(a), the organic light-emitting element of the present invention may also have a hole injection layer, an electron blocking layer, an electron injection layer, etc., and may have multiple such layers. Furthermore, it may be composed of an inorganic compound. Furthermore, a variety of layer configurations can be adopted, such as providing an insulating layer at the interface between electrodes 2 and 7 and the organic compound layer, providing an adhesive layer or interference layer, or having the electron transport layer 6 or hole transport layer 3 composed of two layers with different ionization potentials.

[0055] The organic compound layer according to the present invention may be formed as a common layer for multiple organic light-emitting elements. A common layer is one that is arranged across multiple organic light-emitting elements and can be formed by coating methods such as spin coating or by performing a vapor deposition method over the entire surface of the substrate.

[0056] Examples of these materials are given below. For the hole transport layer 3, materials that facilitate the injection of holes from the anode 2 and materials with high hole mobility to transport the injected holes to the light-emitting layers 4a and 4b are preferred. Similar materials can be used for the hole injection layer and the electron blocking layer.

[0057] Furthermore, in organic light-emitting devices, materials with a high glass transition temperature are preferred in order to suppress deterioration of the film quality, such as crystallization. Examples of low-molecular-weight and high-molecular-weight materials with high hole mobility include triarylamine derivatives, arylcarbazole derivatives, phenylenediamine derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives, poly(vinylcarbazole), poly(thiophene), and other conductive polymers.

[0058] Specific examples of materials used in the hole transport layer 3 are shown below in HT1 to HT19, but the material is not limited to these examples.

[0059] [ka]

[0060] Furthermore, it is preferable to use compounds with deep LUMO levels, such as hexaazatriphenylene compounds, tetrafluoroquinodimethane compounds, and dichlorodicyanobenzoquinone compounds, as the hole injection layer. Specifically, compounds with HT16 to HT19 levels are examples.

[0061] Preferably, the electron blocking layer contains HT7, HT8, HT9, HT10, HT11, and HT12, which contain carbazole groups. The inclusion of carbazole groups deepens the HOMO level, allowing for the creation of levels in which the HOMO level deepens stepwise in the order of hole transport material, hole blocking material, and light-emitting layers 4a and 4b, enabling hole injection into light-emitting layers 4a and 4b at a low voltage.

[0062] Alkali metals, alkaline earth metals, rare earth metals, and compounds thereof are preferably used as electron injection layers, and generally known materials can be used. Specifically, metallic Ca, LiF, KF, Cs2CO3, etc., can be used, and mixtures thereof may also be used.

[0063] The organic compound layer according to the present invention can be formed using dry processes such as vacuum deposition, ionization deposition, sputtering, and plasma deposition. Alternatively, a wet process can be used in which the layer is formed by dissolving the compound in a suitable solvent and applying a known coating method (e.g., spin coating, dipping, casting, LB method, inkjet method, etc.).

[0064] When layers are formed using methods such as vacuum deposition or solution coating, crystallization is less likely to occur, resulting in excellent stability over time. Furthermore, when forming films using coating methods, it is possible to combine the film with an appropriate binder resin. Examples of the binder resins mentioned above include, but are not limited to, polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenolic resin, epoxy resin, silicone resin, and urea resin. Furthermore, these binder resins may be used individually as homopolymers or copolymers, or as a mixture of two or more types. Additionally, known additives such as plasticizers, antioxidants, and UV absorbers may be used in combination as needed.

[0065] <Protective layer> The organic light-emitting element of the present invention may have a protective layer. The protective layer is composed of a material with extremely low permeability to oxygen and moisture from the outside, such as a silicon nitride (SiN) layer or silicon oxynitride (SiON) layer formed using chemical vapor deposition (CVD), an aluminum oxide layer formed using atomic layer deposition (ALD), silicon oxide, and titanium oxide, and may be a single layer or multiple layers as long as it has sufficient moisture barrier performance. In the case of multiple layers, different materials may be laminated, or the same material may be laminated with varying densities. The protective layer is preferably constructed considering the refractive index so that the light emitted from the organic light-emitting element can be easily extracted outside the device. The protective layer can also be called a sealing layer. Its thickness is not limited, but it is preferably 1.6 μm or more and 3.0 μm or less, and more preferably 2.0 μm or more and 2.8 μm or less.

[0066] <Planarization layer> The organic light-emitting element of the present invention may have a planarization layer, which is intended to fill in the irregularities of the protective layer and is preferably placed on the protective layer. This reduces scattered light caused by the slopes of the irregularities on the surface of the protective layer and suppresses color mixing. The planarization layer is composed of a resin layer formed by coating or the like.

[0067] <Color Filter> The organic light-emitting element of the present invention may have a color filter, which is formed by coating a color resist on the planarization layer and patterning it by lithography. The color resist is composed of, for example, a photocurable resin, and forms a pattern when the area irradiated with ultraviolet light or the like hardens. The UV-cured pattern may be reversed in terms of negative and positive orientation. The color filter may have R (red), G (green), and B (blue) color filters, and the RGB components may be arranged in any of the following ways: stripe, square, delta, or Bayer array.

[0068] <Filled layer> The organic light-emitting element of the present invention may have a packing layer between the color filter and the opposing substrate, which will be described later. The packing layer is made of an organic material such as acrylic resin, epoxy resin, or silicone resin. A planarization layer may also be formed between the color filter and the packing layer. This planarization layer may be the same as or different from the planarization layer placed between the color filter and the protective layer. It is preferable to make the two planarization layers from the same material because it provides high adhesion between the planarization layers outside the display area.

[0069] <Opposite substrate> In the embodiments shown in Figures 1(a) and 2(a), there may be a counter substrate on the opposite side from the substrate 1, and the counter substrate may be made of, for example, a transparent glass substrate or a transparent plastic substrate.

[0070] (Device using organic light-emitting elements) The organic light-emitting element of the present invention can be used as a component of display devices, lighting devices, and the like. Other applications include exposure light sources for electrophotographic image forming apparatuses, backlights for liquid crystal display devices, and light-emitting devices having a white light source and a color filter.

[0071] The display device may also be an image information processing device having an image input unit that receives image information from an area CCD, linear CCD, memory card, etc., an information processing unit that processes the input information, and displays the input image on a display unit. The display device may have a plurality of pixels, and at least one of the plurality of pixels may have an organic light-emitting element of the present invention and an active element such as a transistor connected to the organic light-emitting element.

[0072] Furthermore, the display unit of the imaging device or inkjet printer may have a touch panel function. The driving method for this touch panel function may be infrared, capacitive, resistive, or electromagnetic induction, and is not particularly limited. The display device may also be used as the display unit of a multifunction printer. The following describes various devices and apparatus using the organic light-emitting element of the present invention, with reference to embodiments.

[0073] <Image forming apparatus> Figure 3(a) is a schematic diagram showing the configuration of one embodiment of an image forming apparatus equipped with the exposure apparatus of the present invention. The image forming apparatus of this embodiment is an electrophotographic image forming apparatus having a photoreceptor 27, an exposure light source 28, a developing unit 21, a charging unit 26, a transfer unit 22, a transport unit 23, and a fixing unit 25.

[0074] Light 29 is irradiated from the exposure light source 28, and an electrostatic latent image is formed on the surface of the photoreceptor 27. This exposure light source 28 has the organic light-emitting element of the present invention. The developing unit 21 contains toner, etc., and the charging unit 26 charges the photoreceptor 27. The transfer unit 22 transfers the developed image to a recording medium 24 such as paper, and the transport unit 23 transports the recording medium 24. The fixing unit 25 fixes the image formed on the recording medium 24.

[0075] Figures 3(b) and 3(c) schematically show the configuration of an exposure light source 28 in which a plurality of organic light-emitting elements 10 of the present invention are arranged on a long substrate as light-emitting elements. The arrows in the figures are parallel to the axis of the photoreceptor 27 and represent the row direction in which the organic light-emitting elements 10 are arranged. This row direction is the same as the direction of the axis in which the photoreceptor 27 rotates, and can also be called the long axis direction of the photoreceptor 27.

[0076] Figure 3(b) shows a configuration in which the organic light-emitting elements 10 are arranged along the long axis of the photoreceptor. Figure 3(c) shows a different configuration from (b), in which the organic light-emitting elements 10 are arranged alternately in the column direction in the first and second columns. The first and second columns are positioned at different locations in the row direction. In the first column, multiple organic light-emitting elements 10 are arranged with intervals between them. In the second column, organic light-emitting elements 10 are located at positions corresponding to the intervals between organic light-emitting elements 10 in the first column. That is, multiple organic light-emitting elements 10 are also arranged with intervals between them in the row direction. The arrangement in Figure 3(c) can also be described as a grid arrangement, a staggered arrangement, or a checkerboard pattern in which the organic light-emitting elements 10 are arranged.

[0077] <Display device> Figure 4 is a schematic cross-sectional view in the thickness direction of one embodiment of the display device of the present invention. The display device of the present invention has a plurality of pixels, and at least one of the plurality of pixels is the organic light-emitting element of the present invention.

[0078] Figure 4(a) is a schematic cross-sectional view showing the configuration of one pixel in one embodiment of a display device using an organic light-emitting element of the present invention. In this embodiment, one pixel has three sub-pixels 35, which are divided into 35R (red emission), 35G (green emission), and 35B (blue emission) based on their light emission. In this embodiment, the organic light-emitting element 10 emits white light, and the respective emission colors are obtained by passing the white light emitted from the organic light-emitting element 10 through color filters 34R (red), 34G (green), and 34B (blue). The sub-pixels 35R, 35G, and 35B have the organic light-emitting element 10 on an interlayer insulating layer 31 as a substrate. In this embodiment, an anode 2 is formed for each sub-pixel 35, and each anode 2 is electrically insulated by an insulating layer 32.

[0079] In this embodiment, since light is emitted from the side where the color filters 34R, 34G, and 34B are provided, the cathode 7 is a transparent electrode and the anode 2 is a reflective electrode. The organic compound layer 40 and the cathode 7 are common to multiple pixels.

[0080] In Figure 4(a), 33 is a protective layer. The insulating layer 32 is also called a bank or pixel separation film, and the area of ​​the anode 2 not covered by the insulating layer 32 is in contact with the organic compound layer 40 and becomes a light-emitting region. The protective layer 33 reduces the penetration of moisture into the organic compound layer 40. The protective layer 33 may be a single layer or multiple layers. In the case of multiple layers, each layer may be an inorganic compound layer and an organic compound layer.

[0081] The color filters 34R, 34G, and 34B may be formed on a planarization layer (not shown). Alternatively, a resin protective layer (not shown) may be present on the color filters 34R, 34G, and 34B. The color filters 34R, 34G, and 34B may be bonded to an opposing substrate, such as a glass substrate, after being mounted on it.

[0082] The size of the light-emitting region surrounded by the insulating layer 32 is preferably 5 μm or more and 15 μm or less, and more specifically, it may be 11 μm, 9.5 μm, 7.4 μm, 6.4 μm, etc. Also, the spacing between sub-pixels may be 10 μm or less, and specifically, it may be 8 μm, 7.4 μm, 6.4 μm, etc.

[0083] Pixels can take on known arrangements in a plan view. For example, they may be in a stripe arrangement, delta arrangement, pentile arrangement, or Bayer arrangement. The shape of subpixels in a plan view may be any known shape. For example, rectangles, rhombuses, hexagons, etc. Of course, even if it is not a precise shape, if it is close to a rectangle, it is included in the category of rectangles. The shape of subpixels and the pixel arrangement can be used in combination.

[0084] Figure 4(b) is a schematic cross-sectional view showing the pixel configuration of another embodiment of the display device using the organic light-emitting element of the present invention. In this embodiment, a transistor 48 is connected to the organic light-emitting element 10. The transistor 48 in Figure 4(b) is a thin-film transistor (TFT), but it may be a transistor other than a TFT or an active element other than a transistor.

[0085] In this embodiment, a substrate 41 made of glass, silicon, or the like is provided, and an insulating layer 42 is provided on top of it. A transistor 48 is placed on the insulating layer 42. The transistor 48 consists of a gate electrode 43, a gate insulating film 44, a semiconductor layer 45, a drain electrode 46, and a source electrode 47. An insulating film 49 is provided on top of the transistor 48, and the anode 2 of the organic light-emitting element 10 and the source electrode 47 of the transistor 48 are connected via a contact hole 50 provided in the insulating film 49.

[0086] Furthermore, the method of electrical connection between the electrodes (anode 2, cathode 7) included in the organic light-emitting element 10 and the electrodes (source electrode 47, drain electrode 46) included in the transistor 48 is not limited to the configuration shown in Figure 4(b). In other words, it is sufficient if either anode 2 or cathode 7 is electrically connected to either the source electrode 47 or the drain electrode 46 of the TFT. In Figure 4(b), 51 and 52 are protective layers for reducing the degradation of the organic light-emitting element 10.

[0087] The transistor 48 is not limited to a TFT having an active layer (semiconductor layer 45) on the insulating surface of the substrate 41, but may also be a transistor using a single-crystal silicon wafer. Examples of the active layer include non-single-crystal silicon such as single-crystal silicon, amorphous silicon, and microcrystalline silicon, and non-single-crystal oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide. Therefore, in this embodiment as well, the transistor 48 may be formed within the substrate 41, such as a silicon substrate. Here, being formed within the substrate 41 means that the transistor is manufactured by processing the substrate 41 itself, such as a silicon substrate. In other words, having a transistor within the substrate 41 can also be seen as the substrate 41 and the transistor 48 being formed as a single unit. Whether to provide the transistor within the substrate 41 or to use a TFT on the substrate 41 is selected depending on the size of the display area. For example, if the size is about 0.5 inches, it is preferable to provide an organic light-emitting element on a silicon substrate.

[0088] In this embodiment, the luminescence brightness of the organic light-emitting element 10 is controlled by a transistor 48, which is an example of a switching element. By arranging multiple organic light-emitting elements 10 in a plane, an image can be displayed using the luminescence brightness of each element.

[0089] In this embodiment, the organic light-emitting element 10 may be incorporated into a pixel circuit. The pixel circuit may be an active-matrix type that independently controls the light emission of the organic light-emitting element 10. The active-matrix circuit may be voltage-programmed or current-programmed. The drive circuit has a pixel circuit for each pixel. The pixel circuit may have a transistor that controls the light emission brightness of the organic light-emitting element 10, a transistor that controls the light emission timing, a capacitor that holds the gate voltage of the transistor that controls the light emission brightness, and a transistor for connecting to GND without going through the organic light-emitting element 10.

[0090] The display device has a display area and a peripheral area surrounding the display area. The display area has a pixel circuit, and the peripheral area has a display control circuit. The mobility of the transistors constituting the pixel circuit may be smaller than the mobility of the transistors constituting the display control circuit.

[0091] The slope of the current-voltage characteristics of the transistors constituting the pixel circuit can be smaller than the slope of the current-voltage characteristics of the transistors constituting the display control circuit. The slope of the current-voltage characteristics can be measured using the so-called Vg-Ig characteristic.

[0092] Figure 5 is an exploded perspective view showing the overall configuration of one embodiment of the display device of the present invention. The display device 60 has a touch panel 63, a display panel 65, a frame 66, a circuit board 67, and a battery 68 between an upper cover 61 and a lower cover 69. Flexible printed circuits (FPCs) 62 and 64 are connected to the touch panel 63 and the display panel 65. Transistors are printed on the circuit board 67. The battery 68 does not need to be provided if the display device is not a portable device, or it may be provided in a different location even if it is a portable device.

[0093] Figure 6 is a schematic front view showing another embodiment of the display device of the present invention. Figure 6(a) is a display device such as a television monitor or a PC monitor. The display device 70 has a frame 71 and a display unit 72. The display unit 72 uses the organic light-emitting element of the present invention.

[0094] Furthermore, the display device 70 has a frame 71 and a base 73 that supports the display unit 72. The base 73 is not limited to the form shown in Figure 6(a), and the lower edge of the frame 71 may also serve as the base. In addition, the frame 71 and the display unit 72 may be curved, and their radius of curvature is preferably 5000 mm or more and 6000 mm or less.

[0095] The display device 80 in Figure 6(b) is a so-called foldable display device, configured to be bendable. The display device 80 has a first display unit 81, a second display unit 82, a housing 83, and a bending point 84. The first display unit 81 and the second display unit 82 are constructed using the organic light-emitting element of the present invention. The first display unit 81 and the second display unit 82 may be a single display device without seams. The first display unit 81 and the second display unit 82 can be separated at the bending point 84. The first display unit 81 and the second display unit 82 may each display different images, or the first and second display units may together display a single image.

[0096] <Imaging device> The organic light-emitting element of the present invention is used in the display unit of an imaging device having an optical unit with multiple lenses and an image sensor that receives light that has passed through the optical unit. The imaging device has a display unit that displays information acquired by the image sensor. The display unit may be an external display unit or a display unit located inside the viewfinder. Examples of imaging devices include digital cameras and digital video cameras.

[0097] Figure 7(a) is a schematic front view showing one embodiment of the imaging device of the present invention. The imaging device 90 of this embodiment has a viewfinder 91, a rear display 92, an operation unit 93, and a housing 94, and the viewfinder 91 is a display unit having the organic light-emitting element of the present invention. The viewfinder 91 may display not only the image to be captured, but also environmental information, imaging instructions, etc. Environmental information may include the intensity of ambient light, the direction of ambient light, the speed at which the subject is moving, the possibility of the subject being obscured by an obstruction, etc.

[0098] Since the optimal timing for imaging is very short, it is best to display the information as quickly as possible. Because organic light-emitting elements have a fast response speed, using the organic light-emitting elements of the present invention enables fast display, making them more suitable than liquid crystal displays when display speed is required.

[0099] The imaging device 90 has an optical section (not shown). The optical section has multiple lenses that form an image on the image sensor housed in the housing 94. The focus can be adjusted by adjusting the relative positions of the multiple lenses. This operation can also be performed automatically. The imaging device may also be called a photoelectric converter. The photoelectric converter does not capture images sequentially, but may include imaging methods such as detecting the difference from the previous image or extracting from an image that is always being recorded.

[0100] <Electronic equipment> The organic light-emitting element of the present invention may be used in the display section of a mobile device. In that case, it may have both a display function and an operating function. Examples of mobile devices include smartphones and other mobile phones, tablets, and head-mounted displays.

[0101] Figure 7(b) is a schematic perspective view showing one embodiment of the electronic device of the present invention. The electronic device 100 has a display unit 101, an operation unit 102, and a housing 103. The housing 103 has a circuit, a printed circuit board having the circuit, a battery, and a communication unit, and the operation unit 102 may be a button or a touch panel type response unit. The operation unit 102 may also be a biometric recognition unit that recognizes fingerprints to unlock or otherwise perform actions. An electronic device having a communication unit can also be called a communication device. The electronic device may further have a camera function by including a lens and an image sensor. Images captured by the camera function are displayed on the display unit. Examples of electronic devices include smartphones and laptop computers.

[0102] <Lighting equipment> Figure 8 is an exploded perspective view showing one embodiment of the lighting device of the present invention. The lighting device 110 of this embodiment includes a housing 111, a light source 112, a circuit board 113, an optical filter 114 that transmits light from the light source 112, and a light diffusion unit 115. The light source 112 is configured using the organic light-emitting element of the present invention and a power supply circuit connected to the organic light-emitting element. The power supply circuit is a circuit that converts AC voltage to DC voltage. The optical filter 114 may be a filter that improves the color rendering of the light source 112. The light diffusion unit 115 can effectively diffuse the light from the light source 112, such as for lighting up, and deliver light over a wide area. The optical filter 114 and the light diffusion unit 115 are provided on the light-emitting side of the lighting. A cover may be provided on the outermost part as needed.

[0103] The lighting device 110 is, for example, a device for illuminating a room. The lighting device 110 may emit white light, daylight white light, or any other color from blue to red, and may also have a dimming circuit for adjusting the brightness of these colors. White light has a color temperature of 4200K, and daylight white light has a color temperature of 5000K. The lighting device 110 may also have a color filter.

[0104] Furthermore, the lighting device 110 may have a heat dissipation section. The heat dissipation section releases heat from inside the device to the outside, and examples include metals with high specific heat, liquid silicone, etc.

[0105] <Mobile> The mobile body of the present invention may be a ship, aircraft, drone, etc. The mobile body has a body and a light fixture installed on the body, and the light fixture has the organic light-emitting element of the present invention and is responsible for emitting light to indicate the position of the body.

[0106] Figure 9 is a schematic perspective view showing an automobile, which is one embodiment of the mobile body of the present invention. The automobile 120 of this embodiment has a taillight 121, which is a lighting device, and the taillight 121 lights up when the brakes are applied or the like. The automobile 120 has a body 123 and a window 122 attached to the body 123. In this embodiment, at least one of the taillight 121 and the window 122 has the organic light-emitting element of the present invention.

[0107] Furthermore, the tail lamp 121 may have a protective member to protect the organic light-emitting element. The protective member has a reasonably high strength and can be made of any transparent material, but it is preferably made of polycarbonate or the like. A frangic acid derivative, an acrylonitrile derivative, or the like may be mixed with the polycarbonate.

[0108] The window 122 may be a transparent display, as long as it is not a window for checking the front and rear of the automobile. If the transparent display has the organic light-emitting element of the present invention, the constituent materials such as electrodes of the organic light-emitting element are made of transparent material.

[0109] <Image display device> The imaging display device having an organic light-emitting element of the present invention can be applied to systems that can be worn as wearable devices such as eyeglasses (smart glasses), HMDs, and smart contact lenses. The imaging display device used in such applications comprises an imaging device capable of photoelectric conversion of visible light and a display device capable of emitting visible light.

[0110] Figure 10(a) illustrates a pair of glasses 140, which is one example of an application of the imaging display device. An imaging device 142, such as a CMOS sensor or SPAD, is provided on the front surface of the lens 141 of the glasses 140. A display device (not shown) having the organic light-emitting element of the present invention is provided on the back surface of the lens 141.

[0111] The eyeglasses 140 further include a control device 143. The control device 143 functions as a power supply that provides power to the imaging device 142 and the display device according to each embodiment. The control device 143 also controls the operation of the imaging device 142 and the display device. The lens 141 has an optical system formed therein for focusing light onto the imaging device 142.

[0112] Figure 10(b) also shows eyeglasses, but its configuration is slightly different from that of Figure 10(a). The eyeglasses 150 in Figure 10(b) have a control device 152, which is equipped with an imaging device corresponding to the imaging device 142 in Figure 10(a) and a display device having the organic light-emitting element of the present invention. The lens 151 has an optical system formed therein for projecting light emitted from the imaging device and the display device within the control device 152, and an image is projected onto the lens 151. The control device 152 functions as a power supply to provide power to the imaging device and the display device, and also controls the operation of the imaging device and the display device. The control device 152 may have a gaze detection unit that detects the wearer's gaze. Gaze detection may use infrared light. The infrared light-emitting unit emits infrared light towards the eyeball of the user who is fixating on the displayed image. The imaging unit, which has a photodetector, detects the reflected light from the eyeball of the emitted infrared light, thereby obtaining an image of the eyeball. By having a reduction means that reduces the light from the infrared light-emitting unit to the display unit in planar view, the deterioration of image quality is reduced.

[0113] The user's gaze towards the displayed image is detected from an image of the eyeball obtained by imaging with infrared light. Any known method can be applied to gaze detection using an image of the eyeball. For example, a gaze detection method based on the Purkinje image obtained by the reflection of the irradiated light from the cornea can be used.

[0114] More specifically, gaze detection processing is performed based on the pupil-corneal reflection method. Using the pupil-corneal reflection method, a gaze vector representing the orientation (rotation angle) of the eyeball is calculated based on the pupil image and Purkinje image contained in the captured image of the eyeball, thereby detecting the user's gaze.

[0115] The imaging display device of this embodiment has an imaging device having a light receiving element, and may control the display image of the display device based on the user's line-of-sight information from the imaging device. Specifically, the display device determines, based on the line-of-sight information, a first field-of-view region that the user gazes at and a second field-of-view region other than the first field-of-view region. The first field-of-view region and the second field-of-view region may be determined by the control device of the display device, or the display device may receive those determined by an external control device. In the display area of the display device, the display resolution of the first field-of-view region may be controlled to be higher than that of the second field-of-view region. That is, the resolution of the second field-of-view region may be made lower than that of the first field-of-view region.

[0116] Further, the display area has a first display area and a second display area different from the first display area, and based on the line-of-sight information, a region with a higher priority is determined from the first display area and the second display area. The first field-of-view region and the second field-of-view region may be determined by the control device of the display device, or the display device may receive those determined by an external control device. The resolution of the region with a higher priority may be controlled to be higher than that of the region other than the region with a higher priority. That is, the resolution of the region with a relatively lower priority may be made lower.

[0117] In addition, AI may be used to determine the first field-of-view region or the region with a higher priority. AI may be a model configured to estimate the angle of the line of sight and the distance to the object at the tip of the line of sight from the eye image using the eye image and the direction in which the eye in the image is actually looking as teacher data. The AI program may be possessed by the display device, the imaging device, or an external device. When an external device has it, it is transmitted to the display device via communication.

[0118] When performing display control based on visual recognition detection, it is preferably applicable to smart glasses further having an imaging device for imaging the outside. The smart glasses can display the imaged external information in real time.

Example

[0119] (Example 1) <Evaluation of HOMO·LUMO levels> The host material, luminescent dopant material, functional layer material, and electron transport layer material were evaluated using the method described below. The measured values ​​of the HOMO and LUMO levels obtained are shown in Tables 1 and 2.

[0120] [Method for evaluating HOMO levels] A thin film with a thickness of 30 nm was formed on an aluminum substrate, and this thin film was measured using an AC-3 (manufactured by Riken Keiki Co., Ltd.).

[0121] [Method for evaluating LUMO levels] A thin film with a thickness of 30 nm was formed on a quartz substrate, and the optical band gap (absorption edge) of the material under measurement was determined using a spectrophotometer (V-560, manufactured by JASCO Corporation). The sum of this optical band gap value and the aforementioned HOMO level value was defined as the LUMO level.

[0122] The second decimal place of the numerical values ​​shown here may contain measurement errors. Therefore, in this invention, the second decimal place is rounded off and used as the energy level value to determine the material selection when fabricating the elements in the examples and comparative examples.

[0123] [Table 1]

[0124] [Table 2]

[0125] (Example 2) In this embodiment, a blue organic light-emitting element with a top-emission structure was fabricated, in which an anode, hole injection layer, hole transport layer, electron blocking layer, first light-emitting layer, functional layer, electron transport layer, electron injection layer, and cathode were sequentially formed on a substrate.

[0126] Al (65 nm) / Ti (6 nm) was deposited on a glass substrate by sputtering, and the pattern was formed using photolithography to create the anode. At this time, the area of ​​the electrode facing the cathode was 3 mm².2 This is the result.

[0127] Next, the substrate and material, with the washed electrodes already formed, are mounted into the vacuum deposition apparatus (manufactured by ULVAC), and the 1.0 × 10 -4 Pa(1 × 10) -6 After exhausting to Torr, UV / ozone cleaning was performed. Subsequently, each layer was fabricated with the layer configuration shown in Table 3 below.

[0128] The resulting blue organic light-emitting element has the configuration of the present invention [1] and preferred configurations [5] and [6]. It also satisfies formulas [4] and [3-1] in configuration [1].

[0129] [Table 3]

[0130] After forming the cathode, the substrate was transferred to a glove box and sealed with a glass cap containing a desiccant in a nitrogen atmosphere to obtain a white organic light-emitting element.

[0131] The obtained white organic light-emitting diodes were connected to a voltage application device, and their characteristics were evaluated. Current-voltage characteristics were measured using a Hewlett-Packard 4140B micro-ammeter, and emission spectra were obtained and chromaticity evaluated using a Topcon SR-3. Luminous intensity was measured using a Topcon BM7.

[0132] 1000 cd / m² 2 The efficiency, voltage, and CIE chromaticity coordinates during display were 3.3 cd / A, 3.4 V, and (0.16, 0.18), respectively, indicating a high-efficiency, low-voltage blue organic light-emitting element.

[0133] Next, a DC current of 120 mA was continuously applied, and the change in luminescence over time was measured using a Topcon BM7. As a result, it took 90 hours for the luminance to degrade by 5%, indicating that it was a blue organic light-emitting element with good durability.

[0134] (Example 3) Except for changing the materials used for the light-emitting layer and the functional layer to the materials shown in Table 4, the same device as in Example 2 was fabricated and evaluated in the same manner.

[0135] As a result, 1000 cd / m 2 The efficiency, voltage, and CIE chromaticity coordinates during display were 3.2 cd / A, 3.4 V, and (0.16, 0.17), respectively, indicating a good blue organic light-emitting element comparable to that of Example 2.

[0136] Furthermore, the time it took for the brightness to degrade by 5% was 100 hours, indicating that it was a highly durable blue organic light-emitting element.

[0137] (Comparative Example 1) An element similar to that in Example 2 was fabricated and evaluated in the same manner, except that the materials used for the light-emitting layer and the functional layer were changed to the materials shown in Table 4. This element does not satisfy the relationship in equation [3] of the configuration [1] of the present invention.

[0138] This element has a capacitance of 1000 cd / m². 2 The efficiency, voltage, and CIE chromaticity coordinates during display were 3.5 cd / A, 3.7 V, and (0.16, 0.17), respectively, indicating a blue organic light-emitting element with a higher voltage compared to Example 2.

[0139] However, the time required for the brightness to degrade by 5% was 40 hours, which was a less durable blue organic light-emitting element compared to Example 2.

[0140] [Table 4]

[0141] (Example 4) In this embodiment, a white organic light-emitting element with a top-emission structure was fabricated, in which an anode, hole injection layer, hole transport layer, electron blocking layer, first light-emitting layer, second light-emitting layer, functional layer, electron transport layer, electron injection layer, and cathode were sequentially formed on a substrate. The element was fabricated and evaluated in the same manner as in Example 2, except that the second light-emitting layer was deposited. The layer configuration is shown in Table 5.

[0142] The obtained white organic light-emitting element has the configuration [1] of the present invention and preferred configurations [2] to [6]. Furthermore, it also satisfies formulas [4] and [3-1] in configuration [1] and formula [5-1] in configuration [2].

[0143] [Table 5]

[0144] Also, 1000 cd / m² 2 The efficiency, voltage, and CIE chromaticity coordinates during display were 7.1 cd / A, 3.5 V, and (0.25, 0.30), respectively, indicating a high-efficiency, low-voltage white organic light-emitting element with excellent performance.

[0145] Furthermore, the time required for the brightness to degrade by 5% was 1100 hours, indicating that it was a highly durable white organic light-emitting element.

[0146] (Examples 5 to 12) Except for changing the materials used for the light-emitting layer and the functional layer to the materials shown in Table 6, the same device as in Example 4 was fabricated and evaluated in the same manner.

[0147] The evaluation results showed that the organic light-emitting devices of Examples 5 to 12 exhibited virtually no change in device characteristics compared to Example 4 in terms of efficiency, voltage, and CIE chromaticity coordinates, and were white organic light-emitting devices with low drive voltage and good durability.

[0148] Furthermore, the time required for the brightness to degrade by 5% was as follows: Example 5: 1200h Example 6: 1100h Example 7: 1200h Example 8: 1000h Example 9: 1100h Example 10: 1000h Example 11: 1200h Example 12: 1100h

[0149] The white organic light-emitting element obtained here has the configuration [1] of the present invention, similar to Example 4, and further has preferred configurations [2] to [6] of the present invention. Furthermore, it satisfies formula [4] and formula [3-1] or [3-2] in configuration [1], and formula [5-1] in configuration [2]. Therefore, it is considered that the element has a low drive voltage and good durability, similar to that of Example 2.

[0150] (Comparative Example 2) As shown in Table 6, the element was fabricated in the same manner as in Example 4, except that EM4 was used as the material for the functional layer. This element does not satisfy the relationship in equation [3] of the configuration [1] of the present invention. Therefore, 1000 cd / m² 2 The efficiency, voltage, and CIE chromaticity coordinates during display were 7.0 cd / A, 3.8 V, and (0.22, 0.21), respectively. Compared to Example 1, the chromaticity was more blue-oriented, the blue emission brightness was higher, but the element required a higher voltage. Furthermore, the time required for the brightness to degrade by 5% was 800 hours, making it a white organic light-emitting element with less durability compared to Example 2.

[0151] (Comparative Example 3) As shown in Table 6, the element was fabricated in the same manner as in Example 5, except that ET7 was used as the material for the functional layer. This element does not satisfy the relationship in equation [3] of the configuration [1] of the invention. Furthermore, it does not have the preferred configurations [5] and [6] of the present invention. Therefore, 1000 cd / m² 2 The efficiency, voltage, and CIE chromaticity coordinates during display were 7.1 cd / A, 4 bV, and (0.24, 0.28), respectively, indicating that it was a high-voltage element. Furthermore, the time required for the brightness to degrade by 5% was 650 hours, indicating that this white organic light-emitting element had less durability compared to Example 2.

[0152] [Table 6]

[0153] As described above, the present invention provides an organic light-emitting element that is less prone to deterioration in durability at low voltages, and equipment and devices using the element, by having a light-emitting layer and a functional layer whose energy levels have a specific relationship. [Explanation of Symbols]

[0154] 2: Anode, 4a: First light-emitting layer, 4b: Second light-emitting layer, 5: Functional layer, 6: Electron transport layer, 10: Organic light-emitting element, 7: Cathode

Claims

1. An organic light-emitting device having an anode, a first light-emitting layer, a functional layer in contact with the first light-emitting layer, and a cathode in this order, the first emitting layer comprises a first host material and a first dopant material; The LUMO energy levels of the first host material and the first dopant material are h1 , LUMO d1 The HOMO energy levels of the first host material, the first dopant material, and the organic material constituting the functional layer are defined as HOMO h1 , H.O.M.O. d1 , H.O.M.O. FL When the above formula (1) is satisfied, the following formulas [1] to [4] are satisfied. LUMO h1 >LUMO d1 [1] HOMO h1 >HOMO d1 [2] HOMO FL >HOMO h1 [3]

2. The organic light-emitting device according to claim 1 , wherein the organic light-emitting device satisfies the following formula [4]: |LUMO h1 -Louise d1 |>|HOMO h1 -HOMO d1 |[4]

3. 3. The organic light-emitting device according to claim 1, wherein the organic light-emitting device satisfies the following formula [3-1]: HOMO FL -HOMO h1 ≧0.05[eV] [3-1]

4. 3. The organic light-emitting device according to claim 1, wherein the organic light-emitting device satisfies the following formula [3-2]: HOMO FL -HOMO h1 ≧0.15[eV] [3-2]

5. a second light-emitting layer is provided on the anode side of the first light-emitting layer in contact with the first light-emitting layer, the second light-emitting layer comprises a second host material and a second dopant material; The HOMO energy levels of the second dopant material and the second host material are adjusted to HOMO d2 , H.O.M.O. h2 5. The organic light-emitting device according to claim 1, wherein the following formula [5] is satisfied: HOMO d2 >HOMO h2 [5]

6. The organic light-emitting device according to claim 5, wherein the organic light-emitting device satisfies the following formula [5-1]: HOMO d2 -HOMO h2 >0.4[eV] [5-1]

7. The organic light-emitting device according to claim 5 , wherein the first host material and the second host material are the same.

8. the second light-emitting layer comprises a third dopant material; the first dopant material is a blue light-emitting dopant material; the second dopant material is a red light-emitting dopant material; the third dopant material is a green light-emitting dopant material; The HOMO energy level of the third dopant material is d3 8. The organic light-emitting device according to claim 5, wherein the following formula [6] is satisfied: HOMO d3 >HOMO h2 [6]

9. 8. The organic light-emitting element according to claim 1, wherein the organic material constituting the functional layer is composed only of a hydrocarbon.

10. The present invention relates to a semiconductor device having a cathode side of the functional layer, the cathode side of the functional layer, and an electron transport layer made of an organic material in contact with the functional layer, 10. The organic light-emitting element according to claim 1, wherein the electron transport layer is made of an organic compound having an oxadiazole derivative, an oxazole derivative, a pyrazine derivative, a triazole derivative, a triazine derivative, a quinoline derivative, a quinoxaline derivative, or a phenanthroline derivative.

11. an electron transport layer made of an organic material is provided on the cathode side of the functional layer and in contact with the functional layer; The HOMO energy level of the organic material constituting the functional layer and the electron transport layer is FL , H.O.M.O. ETL 10. The organic light-emitting device according to claim 1, wherein the following formula [7] is satisfied: HOMO FL >HOMO ETL [7]

12. The organic light-emitting element described in claim 11, characterized in that the electron transport layer is made of an organic compound having an oxadiazole derivative, an oxazole derivative, a pyrazine derivative, a triazole derivative, a triazine derivative, a quinoline derivative, a quinoxaline derivative, or a phenanthroline derivative.

13. A display device comprising a plurality of pixels, at least one of the pixels comprising the organic light-emitting element according to claim 1 and an active element connected to the organic light-emitting element.

14. The imaging device includes an optical unit having a plurality of lenses, an image sensor that receives light that has passed through the optical unit, and a display unit. The display unit displays information acquired by the imaging element, and the imaging apparatus includes the display device according to claim 13.

15. The device has a housing, a communication unit that communicates with the outside, and a display unit, The electronic device according to claim 13, wherein the display unit comprises the display device according to claim 13.

16. A lighting device having a light source and a light diffusion unit or an optical filter, A lighting device, comprising the organic light-emitting element according to claim 1 , wherein the light source comprises an organic light-emitting element.

17. The drone has a body and a lighting device provided on the body, A moving object, comprising: a lighting device comprising the organic light-emitting element according to claim 1 .

18. An exposure light source for an electrophotographic image forming apparatus, comprising the organic light emitting device according to claim 1 .

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