JP2020053672A - Organic electroluminescent device, organic electroluminescent panel, and electronic apparatus - Google Patents

Abstract

To provide an organic electroluminescent element capable of improving light extraction efficiency, an organic electroluminescent panel including the same, and an electronic apparatus.SOLUTION: The organic electroluminescent element includes: an anode; a light-emitting layer; and a cathode in this order, and includes a low refractive index layer having a lower refractive index than the light-emitting layer at least between the light-emitting layer and the cathode or between the anode and the light-emitting layer.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an organic electroluminescent device, an organic electroluminescent panel, and an electronic device.

  Various types of organic electroluminescent devices (organic electroluminescent displays) using organic electroluminescent elements have been proposed (see, for example, Patent Document 1).

JP 2017-072812 A

  By the way, in the organic electroluminescent device, generally, it is required to improve the light extraction efficiency of the organic electroluminescent element. Therefore, it is desirable to provide an organic electroluminescent element capable of improving light extraction efficiency, and an organic electroluminescent panel and an electronic device including such an organic electroluminescent element.

  An organic electroluminescent device according to an embodiment of the present disclosure includes an anode, a light-emitting layer and a cathode in this order, between the light-emitting layer and the cathode, and at least one between the anode and the light-emitting layer, A low refractive index layer having a lower refractive index is provided.

  An organic electroluminescent panel according to an embodiment of the present disclosure includes a plurality of pixels. Each pixel has the above-mentioned organic electroluminescent element.

  An electronic device according to an embodiment of the present disclosure includes the organic electroluminescent panel described above, and a drive circuit that drives the organic electroluminescent panel.

  In an organic electroluminescent element, an organic electroluminescent panel, and an electronic device according to an embodiment of the present disclosure, the refractive index of the light emitting layer is lower than at least one of between the light emitting layer and the cathode and between the anode and the light emitting layer. A low low refractive index layer is provided. Thereby, for light traveling from the light emitting layer to the low refractive index layer, the critical angle at the interface of the low refractive index layer becomes small, so that light traveling from the light emitting layer to the low refractive index layer is reflected at the interface of the low refractive index layer. The ratio is higher than when the low refractive index layer is not provided. As a result, the ratio of non-radiative deactivation (evanescent mode) due to surface plasmons and the like in the anode and in the vicinity of the anode is reduced, so that the ratio of the external emission mode and the waveguide mode is increased.

  According to the organic electroluminescent device, the organic electroluminescent panel, and the electronic apparatus according to the embodiment of the present disclosure, the refractive index of the light emitting layer is provided between the light emitting layer and the cathode, and at least one between the anode and the light emitting layer. Since a lower refractive index layer is provided, the ratio of the external emission mode and the waveguide mode can be increased. As a result, light extraction efficiency can be improved. Note that the effects of the present disclosure are not necessarily limited to the effects described here, and may be any of the effects described in this specification.

FIG. 1 is a diagram illustrating a cross-sectional configuration example of an organic electroluminescent device according to a first embodiment of the present disclosure. (A) illustrates an example of a mode ratio of a propagation mode of energy generated in an organic electroluminescent element according to a comparative example. (B) illustrates a configuration example of a propagation mode of energy generated in the organic electroluminescent element according to the embodiment. FIG. 4 illustrates an example of a refractive index of a low refractive index layer and a mode ratio of a propagation mode in an organic electroluminescent element that emits red light. FIG. 4 illustrates an example of a refractive index of a low refractive index layer and a mode ratio of a propagation mode in an organic electroluminescent device that emits green light. FIG. 4 illustrates an example of a refractive index of a low refractive index layer and a mode ratio of a propagation mode in an organic electroluminescent device that emits blue light. FIG. (A) illustrates an example of a mode ratio of a propagation mode of energy generated in an organic electroluminescent element according to a comparative example. (B) illustrates a configuration example of a propagation mode of energy generated in the organic electroluminescent element according to the embodiment. FIG. 4 illustrates an example of a refractive index of a low refractive index layer and a mode ratio of a propagation mode in an organic electroluminescent element that emits red light. FIG. 4 illustrates an example of a refractive index of a low refractive index layer and a mode ratio of a propagation mode in an organic electroluminescent device that emits green light. FIG. 4 illustrates an example of a refractive index of a low refractive index layer and a mode ratio of a propagation mode in an organic electroluminescent device that emits blue light. FIG. FIG. 4 is a diagram illustrating a modification of the cross-sectional configuration of the organic electroluminescent device of FIG. 1. FIG. 4 is a diagram illustrating a modification of the cross-sectional configuration of the organic electroluminescent device of FIG. 1. FIG. 11 is a diagram illustrating a modification of the cross-sectional configuration of the organic electroluminescence device of FIG. 10. FIG. 13 is a diagram illustrating an example of a cross-sectional configuration of the organic electroluminescent device of FIGS. 11 and 12. FIG. 13 is a diagram illustrating an example of a cross-sectional configuration of the organic electroluminescent device of FIGS. 11 and 12. FIG. 13 is a diagram illustrating an example of a cross-sectional configuration of the organic electroluminescent device of FIGS. 11 and 12. FIG. 6 is a diagram illustrating a schematic configuration example of an organic electroluminescent device according to a second embodiment of the present disclosure. FIG. 17 is a diagram illustrating a circuit configuration example of a sub-pixel included in each pixel in FIG. 16. FIG. 17 is a diagram illustrating a schematic configuration example of the organic electroluminescent panel of FIG. 16. FIG. 19 is a diagram illustrating an example of a cross-sectional configuration taken along line AA of the organic electroluminescent panel of FIG. 18. FIG. 19 is a diagram illustrating an example of a cross-sectional configuration taken along line BB of the organic electroluminescent panel of FIG. 18. FIG. 19 is a diagram illustrating a cross-sectional configuration example of the organic electroluminescent panel of FIG. 18 taken along line CC. FIG. 17 is a diagram illustrating a modification of the schematic configuration of the organic electroluminescent panel of FIG. 16. FIG. 23 is a diagram illustrating a cross-sectional configuration example of the organic electroluminescent panel of FIG. 22 taken along line BB. FIG. 23 is a diagram illustrating a cross-sectional configuration example of the organic electroluminescent panel of FIG. 22 taken along line CC. FIG. 19 is a diagram illustrating a modification of the cross-sectional configuration taken along line AA of the organic electroluminescent panel of FIG. 18. FIG. 19 is a diagram illustrating a modification of the cross-sectional configuration taken along line BB of the organic electroluminescent panel of FIG. 18. FIG. 19 is a diagram illustrating a modification of the cross-sectional configuration taken along line CC of the organic electroluminescent panel of FIG. 18. FIG. 1 is a perspective view schematically illustrating an example of an external appearance of an electronic apparatus including an organic electroluminescent device according to the present disclosure. FIG. 1 is a perspective view schematically illustrating an example of an external appearance of a lighting device including the organic electroluminescent element of the present disclosure.

Hereinafter, embodiments for carrying out the present disclosure will be described in detail with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present disclosure. Therefore, the numerical values, shapes, materials, constituent elements, arrangement positions of constituent elements, connection forms, and the like shown in the following embodiments are merely examples and do not limit the present disclosure. Therefore, among the components in the following embodiments, components that are not described in the independent claims that indicate the highest concept of the present disclosure are described as arbitrary components. Each drawing is a schematic diagram, and is not necessarily strictly illustrated. In addition, in each of the drawings, substantially the same configuration is denoted by the same reference numeral, and redundant description will be omitted or simplified. The description will be made in the following order.

1. First embodiment (organic electroluminescent device)
1. Example in which a low refractive index layer is provided between a light emitting layer and a cathode Modification of First Embodiment (Organic Electroluminescent Element)
Modification A: An example in which a low refractive index layer is provided between an anode and a light emitting layer Modification B: An example in which a hole injection layer is formed of a laminate Modification C: An example in which a light distribution control layer is provided on a cathode 3. Second embodiment (organic electroluminescent panel, organic electroluminescent device)
3. Example in which organic electroluminescent element according to first embodiment, modification A and modification B is provided. Modified example of second embodiment (organic electroluminescent panel, organic electroluminescent device)
4. Example in which organic electroluminescent element according to modification C is provided Application examples (electronic equipment, lighting equipment)

<1. First Embodiment>
[Constitution]
FIG. 1 illustrates an example of a cross-sectional configuration of the organic electroluminescent device 1 according to the first embodiment of the present disclosure. The organic electroluminescent element 1 is provided, for example, on a substrate 10. The organic electroluminescent device 1 includes, for example, a light-emitting layer 14 and an anode 11 and a cathode 17 arranged so as to sandwich the light-emitting layer 14. The organic electroluminescent device 1 further includes, for example, a hole injection layer 12 and a hole transport layer 13 between the anode 11 and the light emitting layer 14 in this order from the anode 11 side. The organic electroluminescent element 1 further includes, for example, an electron transport layer 15 and an electron injection layer 16 between the light emitting layer 14 and the cathode 17 in this order from the light emitting layer 14 side. Note that at least one of the hole injection layer 12 and the hole transport layer 13 may be omitted.

  Either the electron transport layer 15 or the electron injection layer 16 corresponds to a specific example of the “low refractive index layer” of the present disclosure. Hereinafter, of the electron transport layer 15 and the electron injection layer 16, a layer corresponding to a specific example of the “low refractive index layer” of the present disclosure is referred to as a low refractive index layer. Note that, of the electron transport layer 15 and the electron injection layer 16, a layer that does not correspond to a specific example of the “low refractive index layer” of the present disclosure may be omitted.

  The organic electroluminescent device 1 further includes, for example, a sealing layer 18 on the cathode 17. The organic electroluminescent device 1 includes, for example, an anode 11, a hole injection layer 12, a hole transport layer 13, a light emitting layer 14, an electron transport layer 15, an electron injection layer 16, a cathode 17, and a sealing layer 18 from the substrate 10 side. The element structure includes the elements in this order. The organic electroluminescent device 1 may further include another functional layer.

  The substrate 10 is, for example, a light-transmitting substrate having light transmissivity such as a transparent substrate, and is, for example, a glass substrate made of a glass material. The substrate 10 is not limited to a glass substrate, but may be a translucent resin substrate made of a translucent resin material such as a polycarbonate resin or an acrylic resin, or a TFT (thin film transistor) substrate which is a back plane of an organic EL display device. There may be.

  The anode 11 is formed, for example, on the substrate 10. The anode 11 is, for example, aluminum (Al), silver (Ag), an alloy of aluminum or silver, or a reflective electrode having reflectivity. The anode 11 is not limited to a reflective electrode, and may be, for example, a transparent electrode having a light transmitting property. Examples of the material for the transparent electrode include a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). The anode 11 may be a laminate of a reflective electrode and a transparent electrode.

  The hole injection layer 12 is a layer for improving hole injection efficiency. The hole injection layer 12 has a function of injecting holes injected from the anode 11 into the light emitting layer 14. The hole injection layer 12 is made of, for example, an oxide such as silver (Ag), molybdenum (Mo), chromium (Cr), vanadium (V), tungsten (W), nickel (Ni), iridium (Ir), or It is made of a conductive polymer material such as PEDOT (a mixture of polythiophene and polystyrene sulfonic acid). The hole injection layer 12 may be composed of a single layer, or may have a structure in which a plurality of layers are stacked.

  The hole transport layer 13 has a function of transporting holes injected from the anode 11 to the light emitting layer 14. The hole transport layer 13 is made of, for example, a material (a hole transport material) having a function of transporting holes injected from the anode 11 to the light emitting layer 14. Examples of the hole transporting material include, for example, an arylamine derivative, a triazole derivative, an oxadiazole derivative, an imidazole derivative, a polyarylalkane derivative, a pyrazoline derivative and a pyrazolone derivative, a phenylenediamine derivative, an amino-substituted chalcone derivative, an oxazole derivative, Materials including a styrylanthracene derivative, a fluorenone derivative, a hydrazone derivative, a stilbene derivative, a butadiene compound, a polystyrene derivative, a hydrazone derivative, a triphenylmethane derivative, a tetraphenylbenzine derivative, and the like, or a combination thereof are given. The difference in the HOMO (highest occupied molecular orbital) level of each material of the hole injection layer 12 and the hole transport layer 13 is preferably 0.5 eV or less in consideration of the hole injection property. .

  The light emitting layer 14 is a layer in which holes injected from the anode 11 and electrons injected from the cathode 17 are recombined in the light emitting layer 14 to generate excitons and emit light. The light emitting layer 14 is made of, for example, an organic light emitting material. The light emitting layer 14 is, for example, a coating film, and is formed, for example, by applying and drying a solution containing an organic light emitting material as a solute. The light emitting layer 14 may be composed of a deposited film.

  The organic light emitting material, which is the raw material (material) of the light emitting layer 14, is, for example, a material in which a host material and a dopant material are combined. The organic light emitting material that is the raw material (material) of the light emitting layer 14 may be a single dopant material. The host material mainly has a function of transporting electrons or holes, and the dopant material has a function of emitting light. The host material and the dopant material are not limited to only one type, and may be a combination of two or more types.

  As the host material of the light emitting layer 14, for example, an amine compound, a condensed polycyclic aromatic compound, or a heterocyclic compound is used. As the amine compound, for example, a monoamine derivative, a diamine derivative, a triamine derivative, and a tetraamine derivative are used. Examples of the condensed polycyclic aromatic compound include an anthracene derivative, a naphthalene derivative, a naphthacene derivative, a phenanthrene derivative, a chrysene derivative, a fluoranthene derivative, a triphenylene derivative, a pentacene derivative, and a perylene derivative. As the heterocyclic compound, for example, carbazole derivative, furan derivative, pyridine derivative, pyrimidine derivative, triazine derivative, imidazole derivative, pyrazole derivative, triazole derivative, oxazole derivative, oxadiazole derivative, pyrrole derivative, indole derivative, azaindole derivative, Examples include azacarbazole, pyrazoline derivatives, pyrazolone derivatives, and phthalocyanine derivatives.

  As the dopant material of the light emitting layer 14, for example, a pyrene derivative, a fluoranthene derivative, an arylacetylene derivative, a fluorene derivative, a perylene derivative, an oxadiazole derivative, an anthracene derivative, or a chrysene derivative is used. Further, a metal complex may be used as the fluorescent dopant material of the light emitting layer 14. Examples of the metal complex include those having a metal atom such as iridium (Ir), platinum (Pt), osmium (Os), gold (Au), rhenium (Re), or ruthenium (Ru) and a ligand. Is mentioned.

  The electron transport layer 15 has a function of transporting electrons injected from the cathode 17 to the light emitting layer 14. The electron transport layer 15 includes, for example, a material (electron transport material) having a function of transporting electrons injected from the cathode 17 to the light emitting layer 14. The electron transport layer 15 is composed of, for example, a vapor-deposited film or a sputtered film. The electron transport layer 15 has a charge blocking function of suppressing penetration of charges (holes in the present embodiment) from the light emitting layer 14 to the cathode 17, a function of suppressing quenching of the excited state of the light emitting layer 14, and the like. Is preferred.

  The above-mentioned electron transporting material is, for example, an aromatic heterocyclic compound containing one or more hetero atoms in the molecule. Examples of the aromatic heterocyclic compound include compounds having a skeleton of a pyridine ring, a pyrimidine ring, a triazine ring, a benzimidazole ring, a phenanthroline ring, a quinazoline ring, and the like. The above electron transporting material may be doped with a metal having an electron transporting property. In this case, the electron transport layer 15 is an organic electron transport layer containing a doped metal. Since the electron transport layer 15 contains a metal having an electron transport property, the electron transport property of the electron transport layer 15 can be improved. Examples of the doped metal contained in the electron transport layer 15 include a transition metal such as Yb (ytterbium).

  The electron injection layer 16 has a function of injecting electrons injected from the cathode 17 into the electron transport layer 15 and the light emitting layer 14. The electron injection layer 16 is made of, for example, a material (electron injectable material) having a function of promoting injection of electrons from the cathode 17 to the electron transport layer 15 and the light emitting layer 14. The above-mentioned electron injecting material may be, for example, a material in which an organic material having an electron injecting property is doped with a metal having an electron injecting property. The doping metal contained in the electron injection layer 16 is, for example, the same metal as the doping metal contained in the electron transporting layer 15.

  The cathode 17 is, for example, a transparent electrode such as an ITO film. In addition, the cathode 17 is not limited to a transparent electrode, and may be a reflective electrode having light reflectivity. As a material of the reflective electrode, for example, aluminum (Al), magnesium (Mg), silver (Ag), an aluminum-lithium alloy, a magnesium-silver alloy, or the like is used. In the present embodiment, when the substrate 10 and the anode 11 have reflectivity and the cathode 17 has translucency, the organic electroluminescent device 1 has a top emission in which light is emitted from the cathode 17 side. It has a structure. In this embodiment, when the substrate 10 and the anode 11 have translucency and the cathode 17 has reflectivity, the organic electroluminescent element 1 emits light from the substrate 10 side. It has a bottom emission structure.

  The sealing layer 18 is formed on the cathode 17. The sealing layer 18 is formed, for example, in contact with the upper surface of the cathode 17. The sealing layer 28 is made of, for example, a resin material. Examples of the resin material used for the sealing layer 28 include an epoxy resin and a vinyl resin.

  Next, the low refractive index layer will be described. The low refractive index layer is provided between the light emitting layer 14 and the cathode 17 and is one of the electron transport layer 15 and the electron injection layer 16. That is, the low refractive index layer has a function of injecting or transporting electrons injected from the cathode 17 to the light emitting layer 14. When the electron injection layer 16 is formed of a single layer, the low refractive index layer may correspond to, for example, the entire electron injection layer 16. When the electron injection layer 16 is composed of a stacked body of a plurality of layers, the low refractive index layer may correspond to, for example, the entire electron injection layer 16 or may include at least the low refractive index layer included in the electron injection layer 16. It may correspond to one layer. Further, when the electron transport layer 15 is formed as a single layer, the low refractive index layer may correspond to, for example, the entire electron transport layer 15. When the electron transport layer 15 is composed of a laminate of a plurality of layers, the low refractive index layer may correspond to, for example, the entire electron transport layer 15, or may be included in the electron transport layer 15 at least. It may correspond to one layer.

  The low refractive index layer is formed of a material having a refractive index different from that of the light emitting layer 14 and the cathode 17. Specifically, the low refractive index layer has a refractive index larger than the refractive index of the cathode 17 and smaller than the refractive index of the light emitting layer 14. Here, when the cathode 17 is made of, for example, a metal material with a refractive index of 0.3 and the light emitting layer 14 is made of, for example, an organic material with a refractive index of 1.7, the low refractive index layer is , 0.3 and smaller than 1.7.

  FIG. 2A illustrates an example of a mode ratio of a propagation mode of energy generated in the organic electroluminescent element according to the comparative example. FIG. 2B illustrates a configuration example of a propagation mode of energy generated in the organic electroluminescent element according to the embodiment. In the embodiment, the refractive index of one of the electron transport layer 15 and the electron injection layer 16 is larger than the refractive index of the cathode 17 and smaller than the refractive index of the light emitting layer 14. Other conditions in the comparative example and the example are as follows. 2 (A) and 2 (B), OC indicates an external emission mode, SG indicates a substrate mode, BT indicates a mode leaking to the side opposite to the sealing layer 18 (that is, the substrate 10 side) (leakage mode), AL indicates a mode in which a loss occurs due to absorption in the organic electroluminescent device (loss mode), GM indicates a waveguide mode, and EC indicates an evanescent (non-radiation) mode.

  FIGS. 2A and 2B show simulation results of an organic electroluminescent device having a microcavity structure that generates secondary interference (second cavity) and emits light on the cathode side. . Here, in the comparative example, the anode was formed of a material having a thickness of 200 μm and a refractive index of 0.7, the hole injection layer was formed of a material having a thickness of 10 nm and a refractive index of 1.7, and a hole transport layer was formed. Was formed of a material having a thickness of 180 nm and a refractive index of 1.7, and the light emitting layer 14 was formed of a material having a thickness of 60 nm and a refractive index of 1.7. In the comparative example, the electron transport layer was further formed of a material having a thickness of 10 nm and a refractive index of 1.8, the electron injection layer was formed of a material having a thickness of 10 nm and a refractive index of 2.0, and the cathode was formed of a material having a thickness of 2.0. The sealing layer was made of a material having a thickness of 5 μm and a refractive index of 1.8. On the other hand, in the embodiment, the anode 11 is formed of a material having a thickness of 200 μm and a refractive index of 0.7, the hole injection layer 12 is formed of a material having a thickness of 10 nm and a refractive index of 1.7, and the hole transport is performed. The layer 13 was made of a material having a thickness of 180 nm and a refractive index of 1.7, and the light emitting layer 14 was made of a material having a thickness of 60 nm and a refractive index of 1.7. In the embodiment, the electron transport layer 15 is further formed of a material having a thickness of 10 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a material having a thickness of 10 nm and a refractive index of 1.3, and a cathode 17 is formed. Was formed of a material having a thickness of 15 nm and a refractive index of 0.3, and the sealing layer 18 was formed of a material having a thickness of 5 μm and a refractive index of 1.8.

  2A and 2B, the provision of the low-refractive-index layer between the light-emitting layer 14 and the cathode 17 allows the photon energy to shift from the evanescent mode to the waveguide mode. I understand. Further, it can be seen that the external emission mode increases as the photon energy shifts from the evanescent mode to the waveguide mode. The energy of the photons that have shifted to the waveguide mode is reflected by, for example, the reflector structure that appears in the second embodiment, and can be emitted to the outside as light rising in the front direction.

  The provision of the low-refractive-index layer between the light-emitting layer 14 and the cathode 17 means that the critical angle at the interface of the low-refractive-index layer becomes smaller for light traveling from the light-emitting layer 14 to the low-refractive-index layer. I have. Therefore, in the present embodiment and examples, the ratio of light traveling from the light-emitting layer 14 to the low-refractive-index layer at the interface of the low-refractive-index layer is larger than that in the case where the low-refractive-index layer is not provided. . As a result, the ratio of non-radiative deactivation due to surface plasmons or the like in the vicinity of the anode 11 decreases, so that the ratio of the external emission mode and the waveguide mode increases. Also, the energy radiation distribution from the excitons greatly changes under the influence of the properties (dielectric constant, refractive index, etc.) of the surrounding environment (material). For example, if there is a field having a large refractive index, it is directed toward the field. There are reports that energy is easily emitted. It is guessed that the rate of transition to other modes including this phenomenon is increasing.

  FIG. 3 shows an example of the refractive index of the low refractive index layer and the mode ratio of the propagation mode in the organic electroluminescent device 1 that emits red light. FIG. 4 illustrates an example of the refractive index of the low refractive index layer and the mode ratio of the propagation mode in the organic electroluminescent device 1 that emits green light. FIG. 5 illustrates an example of the refractive index of the low refractive index layer and the mode ratio of the propagation mode in the organic electroluminescent device 1 that emits blue light.

  FIGS. 3 to 5 exemplify simulation results in the case where the organic electroluminescent device 1 has a microcavity structure in which secondary interference (second cavity) is generated and the light emission position is on the cathode 17 side. I have. The refractive index of the low refractive index layer on the horizontal axis shown in FIGS. 3 to 5 indicates the refractive index of the electron injection layer 16.

  In FIG. 3, the anode 11 is formed of a material having a thickness of 200 μm and a refractive index of 0.3, the hole injection layer 12 is formed of a low refractive index material having a thickness of 10 nm, and the hole transport layer 13 is formed of a material having a thickness of 10 nm. The light emitting layer 14 was made of a material having a thickness of 60 nm and a refractive index of 1.7. In FIG. 3, the electron transport layer 15 is formed of a material having a thickness of 10 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a thickness of 10 nm, and the cathode 17 is formed of a material having a thickness of 15 nm and a refractive index of The sealing layer 18 was made of a material having a thickness of 5 μm and a refractive index of 1.8.

  In FIG. 4, the anode 11 is made of a material having a thickness of 200 μm and a refractive index of 0.3, the hole injection layer 12 is made of a low refractive index material having a thickness of 10 nm, and the hole transport layer 13 is formed of a material having a thickness of 10 nm. The light emitting layer 14 was made of a material having a thickness of 60 nm and a refractive index of 1.7. In FIG. 4, the electron transport layer 15 is formed of a material having a thickness of 10 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a thickness of 10 nm, and the cathode 17 is formed of a material having a thickness of 15 nm and a refractive index of The sealing layer 18 was made of a material having a thickness of 5 μm and a refractive index of 1.8.

  In FIG. 5, the anode 11 is formed of a material having a thickness of 200 μm and a refractive index of 0.3, the hole injection layer 12 is formed of a low refractive index material having a thickness of 10 nm, and the hole transport layer 13 is formed of a material having a thickness of 10 nm. The light emitting layer 14 was made of a material having a thickness of 40 nm and a refractive index of 1.7. In FIG. 5, the electron transport layer 15 is formed of a material having a thickness of 10 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a thickness of 10 nm, and the cathode 17 is formed of a material having a thickness of 15 nm and a refractive index of The sealing layer 18 was made of a material having a thickness of 5 μm and a refractive index of 1.8.

  As described above, in the organic electroluminescent device 1 of each emission color, the refractive index of the low refractive index layer is larger than the refractive index of the cathode 17 (for example, 0.3) and the refractive index of the light emitting layer 14 (for example, 0.3). It is preferable to be smaller than 1.7). In the organic electroluminescent device 1 that emits red light, the low refractive index layer preferably has a refractive index of 0.5 or more, which increases the ratio of the waveguide mode. Therefore, in the organic electroluminescent element 1 that emits red light, the refractive index of the low refractive index layer preferably has a value within the range of “a” in FIG. 3 and within the range of “b” in FIG. Is more preferable.

  In the organic electroluminescent device 1 that emits green light, the low refractive index layer preferably has a refractive index of 0.5 or more, which increases the ratio of the waveguide mode. Therefore, in the organic electroluminescent device 1 that emits green light, the refractive index of the low refractive index layer preferably has a value within the range of “a” in FIG. 4, and within the range of “c” in FIG. Is more preferable.

  In the organic electroluminescent device 1 that emits blue light, the refractive index of the low refractive index layer is preferably 0.5 or more, which increases the ratio of the waveguide mode. Therefore, in the organic electroluminescent device 1 that emits blue light, the refractive index of the low refractive index layer preferably has a value within the range of “a” in FIG. 5, and within the range of “d” in FIG. Is more preferable.

[effect]
Next, effects of the organic electroluminescent device 1 according to the present embodiment will be described.

  Various organic electroluminescent devices using organic electroluminescent elements have been proposed. The organic electroluminescent device emits light when excitons are generated by the recombination of electrons and holes injected from the cathode and anode in the light emitting layer, and the excitons return to a low energy level or a ground state. Element. Therefore, in the organic electroluminescent element, it is necessary to effectively inject carriers and effectively extract light to the outside.

  Here, focusing on hole injection among carrier injections, the hole injection layer 12 injects holes into the light emitting layer 14 and loses energy of excitons generated at the emission center near the anode 11. It is important to have the effect of lowering the activity generation rate. Therefore, in the present embodiment, a low refractive index layer having a refractive index larger than the refractive index of the cathode 17 and smaller than the refractive index of the light emitting layer 14 is provided between the light emitting layer 14 and the cathode 17. . Thereby, the critical angle at the interface of the low-refractive-index layer becomes smaller for light traveling from the light-emitting layer 14 to the low-refractive-index layer, so that the light traveling from the light-emitting layer 14 to the low-refractive-index layer is reflected at the interface of the low-refractive-index layer. The ratio is larger than when the low refractive index layer is not provided. As a result, the rate at which excitons radiate and deactivate near the anode 11 due to surface plasmons and the like decreases, so that the rates of the external emission mode and the waveguide mode increase. Therefore, the low-refractive-index layer can promote injection or transport of holes into the light-emitting layer 14 and can improve light extraction efficiency.

  In the present embodiment, when the low refractive index layer is made of a material having a refractive index larger than 0.3 and smaller than 1.7, light traveling from the light emitting layer 14 to the low refractive index layer is used. Therefore, the critical angle at the interface of the low-refractive-index layer becomes smaller, so that the rate at which light traveling from the light-emitting layer 14 toward the low-refractive-index layer is reflected at the interface of the low-refractive-index layer is not provided. It is larger than. As a result, the rate at which excitons radiate and deactivate near the anode 11 due to surface plasmons and the like decreases, so that the rates of the external emission mode and the waveguide mode increase. Therefore, the low-refractive-index layer can promote injection or transport of holes into the light-emitting layer 14 and can improve light extraction efficiency.

  In the organic electroluminescent device 1 that emits red light according to the present embodiment, when the refractive index of the low refractive index layer is 0.5 or more and 1.7 or less, the ratio of the waveguide mode is reduced. growing. Thereby, the injection or transport of holes into the light emitting layer 14 is promoted, and the light extraction efficiency can be improved.

  Further, in the organic electroluminescent device 1 that emits green light according to the present embodiment, when the refractive index of the low refractive index layer is 0.5 or more and 1.7 or less, the ratio of the waveguide mode is reduced. growing. Thereby, the injection or transport of holes into the light emitting layer 14 is promoted, and the light extraction efficiency can be improved.

  In the organic electroluminescent device 1 that emits blue light according to the present embodiment, when the refractive index of the low refractive index layer is 0.5 or more and 1.7 or less, the ratio of the waveguide mode is reduced. growing. Thereby, the injection or transport of holes into the light emitting layer 14 is promoted, and the light extraction efficiency can be improved.

<2. Modification of First Embodiment>
Next, a modification of the organic electroluminescent device 1 according to the first embodiment will be described.

[Modification A]
In the above embodiment, the low refractive index layer is provided between the light emitting layer 14 and the cathode 17. However, in the above embodiment, the low refractive index layer may be provided between the anode 11 and the light emitting layer 14 instead of between the light emitting layer 14 and the cathode 17. In the above embodiment, the low refractive index layer may be provided between the light emitting layer 14 and the cathode 17 and also between the anode 11 and the light emitting layer 14. Hereinafter, the low refractive index layer provided between the anode 11 and the light emitting layer 14 will be described.

  The low refractive index layer is provided between the anode 11 and the light emitting layer 14 and is one of the hole injection layer 12 and the hole transport layer 13. That is, the low refractive index layer has a function of injecting or transporting holes injected from the anode 11 to the light emitting layer 14. When the hole injection layer 12 is formed of a single layer, the low refractive index layer may correspond to, for example, the entire hole injection layer 12. When the hole injection layer 12 is composed of a laminate of a plurality of layers, the low refractive index layer may correspond to, for example, the entire hole injection layer 12, It may correspond to at least one layer included. When the hole transport layer 13 is formed as a single layer, the low refractive index layer may correspond to, for example, the entire hole transport layer 13. When the hole transport layer 13 is composed of a multilayer body of a plurality of layers, the low refractive index layer may correspond to, for example, the entire hole transport layer 13 or may be a layer having a low refractive index. It may correspond to at least one layer included.

  The low refractive index layer is formed of a material having a refractive index different from that of the anode 11 and the light emitting layer 14. Specifically, the low refractive index layer has a refractive index larger than the refractive index of the anode 11 and smaller than the refractive index of the light emitting layer 14. Here, when the anode 11 is made of, for example, a metal material having a refractive index of 0.3 and the light emitting layer 14 is made of, for example, an organic material having a refractive index of 1.7, the low refractive index layer is , 0.3 and smaller than 1.7.

  FIG. 6A illustrates an example of a mode ratio of a propagation mode of energy generated in the organic electroluminescent element according to the comparative example. FIG. 6B illustrates a configuration example of a propagation mode of energy generated in the organic electroluminescent element according to the embodiment. In the comparative example, the refractive indexes of both the hole injection layer 12 and the hole transport layer 13 are equal to the refractive index of the light emitting layer 14. On the other hand, in the example, the refractive index of one of the hole injection layer 12 and the hole transport layer 13 is larger than the refractive index of the anode 11 and smaller than the refractive index of the light emitting layer 14. Other conditions in the comparative example and the example are as follows. 6A and 6B, OC indicates an external emission mode, SG indicates a substrate mode, and BT indicates a mode leaking to the side opposite to the sealing layer 18 (that is, the substrate 10 side) (leakage mode). AL indicates a mode in which a loss occurs due to absorption in the organic electroluminescent device (loss mode), GM indicates a waveguide mode, and EC indicates an evanescent (non-radiation) mode.

  FIGS. 6A and 6B show simulation results of an organic electroluminescent device having a microcavity structure that generates secondary interference (second cavity) and emits light on the anode side. . Here, in the comparative example, the anode was formed of a material having a thickness of 200 μm and a refractive index of 0.7, the hole injection layer was formed of a material having a thickness of 10 nm and a refractive index of 1.7, and a hole transport layer was formed. Was composed of a material having a thickness of 20 nm and a refractive index of 1.7, and the light emitting layer 14 was composed of a material having a thickness of 90 nm and a refractive index of 1.7. In the comparative example, the electron transport layer was further formed of a material having a thickness of 30 nm and a refractive index of 1.8, the electron injection layer was formed of a material having a thickness of 80 nm and a refractive index of 2.0, and the cathode was formed of a material having a thickness of 2.0. The sealing layer was made of a material having a thickness of 5 μm and a refractive index of 1.8. On the other hand, in the embodiment, the anode 11 is made of a material having a thickness of 200 μm and a refractive index of 0.7, and the hole injection layer 12 is made of a material having a thickness of 10 nm and a refractive index of 1.3. The layer 13 was made of a material having a thickness of 20 nm and a refractive index of 1.7, and the light emitting layer 14 was made of a material having a thickness of 90 nm and a refractive index of 1.7. In the embodiment, further, the electron transport layer 15 is formed of a material having a thickness of 30 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a material having a thickness of 80 nm and a refractive index of 2.0, and the cathode 17 is formed. Was formed of a material having a thickness of 15 nm and a refractive index of 0.3, and the sealing layer 18 was formed of a material having a thickness of 5 μm and a refractive index of 1.8.

  6A and 6B that the energy of photons is shifted from the evanescent mode to the waveguide mode by providing a low refractive index layer between the anode 11 and the light emitting layer 14. I understand. Further, it can be seen that the external emission mode increases as the photon energy shifts from the evanescent mode to the waveguide mode. The energy of the photons that have shifted to the waveguide mode is reflected by, for example, the reflector structure that appears in the second embodiment, and can be emitted to the outside as light rising in the front direction.

  The provision of the low-refractive-index layer between the anode 11 and the light-emitting layer 14 means that the critical angle at the interface of the low-refractive-index layer becomes smaller for light traveling from the light-emitting layer 14 to the low-refractive-index layer. I have. Therefore, in the present embodiment and examples, the ratio of light traveling from the light-emitting layer 14 to the low-refractive-index layer at the interface of the low-refractive-index layer is larger than that in the case where the low-refractive-index layer is not provided. . As a result, the ratio of non-radiative deactivation due to surface plasmons or the like in the vicinity of the anode 11 decreases, so that the ratio of the external emission mode and the waveguide mode increases. Also, the energy radiation distribution from the excitons greatly changes under the influence of the properties (dielectric constant, refractive index, etc.) of the surrounding environment (material). For example, if there is a field having a large refractive index, it is directed toward the field. There are reports that energy is easily emitted. It is guessed that the rate of transition to other modes including this phenomenon is increasing.

  FIG. 7 shows an example of the relationship between the refractive index of the low refractive index layer and the mode ratio of the propagation mode in the organic electroluminescent device 1 that emits red light. FIG. 8 illustrates an example of the relationship between the refractive index of the low refractive index layer and the mode ratio of the propagation mode in the organic electroluminescent device 1 that emits green light. FIG. 9 illustrates an example of the relationship between the refractive index of the low refractive index layer and the mode ratio of the propagation mode in the organic electroluminescent device 1 that emits blue light.

  FIGS. 7 to 9 exemplify simulation results in the case where the organic electroluminescent device 1 has a microcavity structure in which secondary interference (second cavity) is generated and the light emission position is on the anode 11 side. I have. The refractive index of the low refractive index layer on the horizontal axis shown in FIGS. 7 to 9 indicates the refractive index of the hole injection layer 12.

  In FIG. 6, the anode 11 is formed of a material having a thickness of 200 μm and a refractive index of 0.3, the hole injection layer 12 is formed of a low refractive index material having a thickness of 10 nm, and the hole transport layer 13 is formed of a material having a thickness of 10 nm. The light emitting layer 14 was made of a material having a thickness of 120 nm and a refractive index of 1.7. In FIG. 6, the electron transport layer 15 is formed of a material having a thickness of 30 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a material having a thickness of 80 nm and a refractive index of 2.0, and the cathode 17 is formed. Was formed of a material having a thickness of 15 nm and a refractive index of 0.3, and the sealing layer 18 was formed of a material having a thickness of 5 μm and a refractive index of 1.8.

  In FIG. 7, the anode 11 is formed of a material having a thickness of 200 μm and a refractive index of 0.3, the hole injection layer 12 is formed of a low refractive index material having a thickness of 10 nm, and the hole transport layer 13 is formed of a material having a thickness of 10 nm. The light-emitting layer 14 was made of a material having a thickness of 90 nm and a refractive index of 1.7. In FIG. 7, the electron transport layer 15 is formed of a material having a thickness of 30 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a material having a thickness of 80 nm and a refractive index of 2.0, and the cathode 17 is formed. Was formed of a material having a thickness of 15 nm and a refractive index of 0.3, and the sealing layer 18 was formed of a material having a thickness of 5 μm and a refractive index of 1.8.

  In FIG. 8, the anode 11 is formed of a material having a thickness of 200 μm and a refractive index of 0.3, the hole injection layer 12 is formed of a low refractive index material having a thickness of 10 nm, and the hole transport layer 13 is formed of a material having a thickness of 10 nm. The light-emitting layer 14 was made of a material having a thickness of 40 nm and a refractive index of 1.7. In FIG. 8, the electron transport layer 15 is made of a material having a thickness of 30 nm and a refractive index of 1.8, the electron injection layer 16 is made of a material having a thickness of 80 nm and a refractive index of 2.0, and a cathode 17 is formed. Was formed of a material having a thickness of 15 nm and a refractive index of 0.3, and the sealing layer 18 was formed of a material having a thickness of 5 μm and a refractive index of 1.8.

  As described above, in the organic electroluminescent element 1 of each emission color, the refractive index of the low refractive index layer is larger than the refractive index of the anode 11 (for example, 0.3), and the refractive index of the light emitting layer 14 (for example, It is preferable to be smaller than 1.7). In the organic electroluminescent device 1 that emits red light, the low refractive index layer preferably has a refractive index of 0.75 or more, which increases the ratio of the waveguide mode. In the organic electroluminescent device 1 that emits red light, the low refractive index layer preferably has a refractive index of 1.4 or less, in which the external emission mode is more dominant than the evanescent mode. Therefore, in the organic electroluminescent device 1 that emits red light, the refractive index of the low refractive index layer preferably has a value within the range of “a” in FIG. 7 and within the range of “b” in FIG. Is more preferable.

  In the organic electroluminescent device 1 that emits green light, the low refractive index layer preferably has a refractive index of 0.5 or more, which increases the ratio of the waveguide mode. Therefore, in the organic electroluminescent device 1 that emits green light, the refractive index of the low refractive index layer preferably has a value within the range of “a” in FIG. 8, and within the range of “c” in FIG. Is more preferable.

  In the organic electroluminescent device 1 that emits blue light, the refractive index of the low refractive index layer is preferably 0.5 or more, which increases the ratio of the waveguide mode. In the organic electroluminescent device 1 that emits blue light, the refractive index of the low refractive index layer is preferably 1.5 or less at which the ratio of the evanescent mode is 50% or less. Therefore, in the organic electroluminescent device 1 that emits blue light, the refractive index of the low-refractive-index layer is preferably a value within the range of “a” in FIG. 9 and within the range of “d” in FIG. Is more preferable.

[effect]
Next, the effect of the organic electroluminescent device 1 according to the present modification will be described.

  In this modification, a low refractive index layer having a refractive index larger than the refractive index of the anode 11 and smaller than the refractive index of the light emitting layer 14 is provided between the anode 11 and the light emitting layer 14. Thereby, the critical angle at the interface of the low-refractive-index layer becomes smaller for light traveling from the light-emitting layer 14 to the low-refractive-index layer, so that the light traveling from the light-emitting layer 14 to the low-refractive-index layer is reflected at the interface of the low-refractive-index layer. The ratio is larger than when the low refractive index layer is not provided. As a result, the rate at which excitons radiate and deactivate near the anode 11 due to surface plasmons and the like decreases, so that the rates of the external emission mode and the waveguide mode increase. Therefore, the low-refractive-index layer can promote injection or transport of holes into the light-emitting layer 14 and can improve light extraction efficiency.

  Further, in this modification, when the low refractive index layer is made of a material having a refractive index larger than 0.3 and smaller than 1.7, light emitted from the light emitting layer 14 to the low refractive index layer is not used. Since the critical angle at the interface of the low-refractive-index layer is reduced, the ratio of light from the light-emitting layer 14 toward the low-refractive-index layer at the interface of the low-refractive-index layer is the same as when the low-refractive-index layer is not provided. It will be larger than that. As a result, the rate at which excitons radiate and deactivate near the anode 11 due to surface plasmons and the like decreases, so that the rates of the external emission mode and the waveguide mode increase. Therefore, the low-refractive-index layer can promote injection or transport of holes into the light-emitting layer 14 and can improve light extraction efficiency.

  In the organic electroluminescent device 1 according to the present modification that emits red light, when the refractive index of the low refractive index layer is 0.75 or more and 1.4 or less, the ratio of the waveguide mode is large. , The external emission mode becomes more dominant than the evanescent mode. Thereby, the injection or transport of holes into the light emitting layer 14 is promoted, and the light extraction efficiency can be improved.

  In the organic electroluminescent device 1 that emits green light according to the present modification, when the refractive index of the low refractive index layer is 0.5 or more and 1.7 or less, the ratio of the waveguide mode is large. Become. Thereby, the injection or transport of holes into the light emitting layer 14 is promoted, and the light extraction efficiency can be improved.

  In the organic electroluminescent device 1 that emits blue light according to the present modification, when the refractive index of the low refractive index layer is 0.5 or more and 1.5 or less, the ratio of the waveguide mode is large. , The ratio of the evanescent mode becomes 50% or less. Thereby, the injection or transport of holes into the light emitting layer 14 is promoted, and the light extraction efficiency can be improved.

[Modification B]
FIG. 10 illustrates a modification of the cross-sectional configuration of the organic electroluminescent element 1 according to the embodiment and the modification A. In the organic electroluminescent device 1 according to the present modification, the hole injection layer 12 includes, for example, a metal oxide layer 12A and an organic material layer 12B laminated on the metal oxide layer 12A.

  The metal oxide layer 12A is configured to include tungsten oxide (in the composition formula WOx, x is generally a real number in the range of 2 <x <3). The thickness of the metal oxide layer 12A is 2 nm or more, for example, 10 nm. The metal oxide layer 12A may contain a trace amount of impurities that can be mixed normally.

  By setting the thickness of the metal oxide layer 12A to 2 nm or more, it is easy to form a uniform tungsten oxide film, and a Schottky ohmic connection between the anode 11 and the metal oxide layer 12A described below is established. It is easy to form. The Schottky ohmic connection is formed stably when the thickness of the tungsten oxide film is 2 nm or more. Therefore, if a thicker tungsten oxide film is formed, a stable hole injection efficiency from the anode 11 to the metal oxide layer 12A can be expected using the Schottky ohmic connection. The “Schottky ohmic connection” refers to a connection in which the difference between the Fermi level of the anode 11 and the lowest binding energy at the occupied level near the Fermi surface of the metal oxide layer 12A is less than or equal to a predetermined value. . The thickness of the metal oxide layer 12A is, for example, 5 nm or more and 20 nm or less.

  The organic layer 12B is formed in contact with the metal oxide layer 12A. The organic layer 12B has an electron blocking property. The organic layer 12B is formed of an organic material such as a conductive polymer material. The organic layer 12B is formed by, for example, applying an organic polymer solution of a conductive polymer material such as PEDOT (a mixture of polythiophene and polystyrene sulfonic acid) on the metal oxide layer 12A and drying. In this case, the organic material layer 12B is constituted by a coating film. The organic material layer 12B further has, for example, a soluble group and an insolubilizing group such as a heat dissociable soluble group, a crosslinkable group or a removable protective group in its molecular structure for the function of solubility and insolubilization. doing. That is, the organic layer 12B is an insolubilized layer.

  The thickness of the organic layer 12B of the blue organic electroluminescent element 1 is preferably, for example, 20 nm or more from the viewpoint of luminous efficiency. The thickness of the organic layer 12B of the blue organic electroluminescent element 1 is preferably, for example, 30 nm or more from the viewpoint of chromaticity. The thickness of the organic layer 12B of the green organic electroluminescent element 1 is preferably, for example, 10 nm or more and 20 nm or less from the viewpoint of luminous efficiency. The thickness of the organic layer 12B of the red organic electroluminescent element 12r is preferably, for example, 30 nm or more from the viewpoint of luminous efficiency. The thickness of the organic layer 12B of the red organic electroluminescent element 12r is preferably, for example, 50 nm or less from the viewpoint of shortening the film formation time.

[Modification C]
FIG. 11 illustrates a modification of the cross-sectional configuration of the organic electroluminescent device 1 according to the above embodiment and Modification A. FIG. 12 illustrates a modification of the cross-sectional configuration of the organic electroluminescent element 1 according to the modification B. The organic electroluminescent device 1 according to the present modification has a light distribution control layer 19 that is in contact with the upper surface of the cathode 17 between the cathode 17 and the sealing layer 18. The light distribution control layer 19 is, for example, a composite layer formed by laminating light transmitting layers 19A, 19B, and 19C in this order from the cathode 17 side, as shown in FIG. The light transmission layers 19A, 19B, 19C are formed of, for example, a transparent conductive material or a transparent dielectric material.

Examples of the transparent conductive material used for the light transmission layers 19A, 19B, and 19C include ITO and IZO. Examples of the transparent dielectric material used for the light transmitting layers 19A, 19B, 19C include silicon oxide (for example, SiO ₂ ), silicon oxynitride (for example, SiON), silicon nitride (for example, SiN), and the like. The light transmission layers 19A, 19B, and 19C may have a function as the cathode 17, or may function as a passivation film. The light transmitting layers 19A, 19B, and 19C may be formed of a low refractive index material such as MgF or NaF, for example.

  The anode 11 and the light transmitting layers 19A, 19B, 19C form a resonator structure. In the present modified example, the sealing layer 18 also has a function of preventing external interference with a resonator structure formed between the anode 11 and the light transmitting layers 19A, 19B, and 19C.

  A reflection surface S1 is formed on the upper surface of the anode 11 due to a difference in refractive index between the anode 11 and a layer (the hole injection layer 12 or the hole transport layer 13) in contact with the upper surface of the anode 11. The reflection surface S1 is arranged at a position at an optical distance L1 from the emission center 14a of the emission layer 14. The optical distance L1 is set so that the light having the center wavelength λ1 of the emission spectrum of the light emitting layer 14 is strengthened by interference between the reflection surface S1 and the light emission center 14a. Specifically, the optical distance L1 is configured to satisfy the following equations (1) and (2). In addition, in the expressions (1) and (2), the unit of L1, λ1, and λ11 is nm.

(2L1 / λ11) + (a1 / 2π) = m1 (1)
λ1-150 <λ11 <λ1 + 80 (2)
a1: a phase change λ11 when light emitted from the light emitting layer 14 is reflected by the reflecting surface S1: a wavelength m1 satisfying the expression (2) m1: an integer of 0 or more.

  a1 can be calculated using n0, k of the complex refractive index N = n0-jk (n0: refractive index, k: extinction coefficient) of the anode 11 and the refractive index of the light emitting layer 14 (for example, Principles of Optics, Max Born and Emil Wolf, 1974 (PERGAMON PRESS) etc.). The complex refractive index of the anode 11 and the refractive index of the light-emitting layer 14 can be measured using, for example, a spectroscopic ellipsometer.

  If the value of m1 is large, a so-called microcavity (micro-resonator) effect cannot be obtained, so it is preferable that m1 = 0. For example, it is preferable that the optical distance L11 satisfies both the following expressions (3) and (4). In equation (4), λ1 = 600 nm.

(2L1 / λ11) + (a1 / 2π) = 0 (3)
λ1-150 = 450 <λ11 = 600 <λ1 + 80 = 680 (4)

  Since the reflection surface S1 satisfying the expression (3) is provided at the position of the 0th-order interference, it exhibits high transmittance over a wide wavelength band. Therefore, as shown in Expression (4), λ11 can be greatly shifted from the center wavelength λ1.

  A reflection surface S2 is formed on the upper surface of the cathode 17 due to a difference in refractive index between the cathode 17 and a layer (light transmission layer 19A) in contact with the upper surface of the cathode 17. The reflection surface S2 is arranged at a position at an optical distance L2 from the light emission center 14a of the light emitting layer 14. The optical distance L2 is set so that light of the center wavelength λ1 of the emission spectrum of the light emitting layer 14 is strengthened by interference between the reflection surface S2 and the light emission center 14a. Specifically, the optical distance L2 is configured to satisfy the following equations (5) and (6). In the expressions (5) and (6), the unit of L2, λ1, and λ12 is nm.

(2L2 / λ12) + (a2 / π) = m2 (5)
λ1-80 <λ12 <λ1 + 80 (6)
a2: a phase change λ12 when light emitted from the light emitting layer 14 is reflected by the reflection surface S2: a wavelength m2 satisfying the expression (6): an integer of 0 or more.

  a2 can be calculated using n0 and k of the complex refractive index N = n0-jk (n0: refractive index, k: extinction coefficient) of the light transmitting layer 19A and the refractive index of the light emitting layer 14. The complex refractive index of the light transmitting layer 19A and the refractive index of the light emitting layer 14 can be measured using, for example, a spectroscopic ellipsometer.

  If the value of m2 is large, a so-called microcavity (micro-resonator) effect cannot be obtained, so it is preferable that m2 = 1.

  Both of the reflection surfaces S1 and S2 are configured to reinforce light generated in the light emitting layer 14 with the light emission center 14a. Due to this amplification effect, a peak of the transmittance occurs near 620 nm.

  For example, as shown in FIG. 14, the cathode 17 is not provided, the light transmitting layer 19A has the role of the cathode 17, and the reflection surface S2 is in contact with the electron transport layer 15 or the electron injection layer 16 by light. It may be formed by a refractive index difference from the transmission layer 19A.

  For example, as shown in FIG. 15, a light transmitting layer 19D is provided between the light transmitting layer 19A and the light transmitting layer 19B, and the light is reflected by a difference in refractive index between the light transmitting layer 19D and the light transmitting layer 19A. The surface S2 may be formed.

  A reflection surface S3 is formed on the upper surface of the light transmission layer 19A due to a difference in refractive index between the light transmission layer 19A and a layer (light transmission layer 19B) in contact with the upper surface of the light transmission layer 19A. The reflection surface S3 is arranged at a position at an optical distance L3 from the light emission center 14a of the light emitting layer 14. In the organic electroluminescent device 1 that emits red light, the optical distance L3 is set so that light of the central wavelength λ1 (λ1R) of the emission spectrum of the light emitting layer 14 is weakened by interference between the reflection surface S3 and the light emission center 14a. Is set to In the organic electroluminescent device 1 that emits blue light, the optical distance L3 is such that light of the central wavelength λ1 (λ1B) of the emission spectrum of the light-emitting layer 14 is strengthened by interference between the reflection surface S3 and the light-emitting center 14a. Is set to Specifically, in the organic electroluminescent device 1 that emits red light, the optical distance L3 is configured to satisfy the following equations (7) and (8). In the organic electroluminescent device 1 that emits blue light, the optical distance L3 is configured to satisfy the following expressions (9) and (10). In the equations (7), (8), (9), and (10), the unit of L3, λ1, and λ13 is nm.

(2L3 / λ13) + (a3 / 2π) = m3 + 1/2 (7)
λ1R−150 <λ13 <λ1R + 150 (8)
(2L3 / λ23) + (a3 / 2π) = n3 (9)
λ1B−150 <λ23 <λ1B + 150 (10)
a3: phase change when light emitted from the light emitting layer 14 is reflected by the reflecting surface S3 λ13: wavelength satisfies the equation (8) λ23: wavelength m3 satisfies the equation (10), n3: an integer of 0 or more.

  A reflection surface S4 is formed on the upper surface of the light transmission layer 19B due to a difference in refractive index between the light transmission layer 19B and a layer (light transmission layer 19C) in contact with the upper surface of the light transmission layer 19B. The reflection surface S4 is arranged at a position at an optical distance L4 from the light emission center 14a of the light emitting layer 14. In the organic electroluminescent device 1 that emits red light, the optical distance L4 is set so that light of the center wavelength λ1 (λ1R) of the emission spectrum of the light emitting layer 14 is weakened by interference between the reflection surface S4 and the light emission center 14a. Is set to In the organic electroluminescent device 1 that emits blue light, the optical distance L4 is such that light of the central wavelength λ1 (λ1B) of the emission spectrum of the light-emitting layer 14 is strengthened by interference between the reflection surface S4 and the light-emitting center 14a. Is set to Specifically, in the organic electroluminescent device 1 that emits red light, the optical distance L4 is configured to satisfy the following expressions (11) and (12). In the organic electroluminescent device 1 that emits blue light, the optical distance L4 is configured to satisfy the following expressions (13) and (14). In the equations (11), (12), (13), and (14), the unit of L4, λ1, and λ14 is nm.

(2L4 / λ14) + (a4 / 2π) = m4 + 1/2 (11)
λ1R-150 <λ14 <λ1R + 150 (12)
(2L4 / λ24) + (a3 / 2π) = n4 (13)
λ1B−150 <λ24 <λ1B + 150 (14)
a4: a phase change when light emitted from the light emitting layer 14 is reflected by the reflection surface S4 λ14: a wavelength λ24 that satisfies the expression (11): a wavelength m4 that satisfies the expression (13), n4: an integer of 4 or more

  a3 can be calculated using n0, k of the complex refractive index N = n0-jk (n0: refractive index, k: extinction coefficient) of the light transmitting layer 19B and the refractive index of the light emitting layer 14. a4 can be calculated using n0, k of the complex refractive index N = n0-jk (n0: refractive index, k: extinction coefficient) of the light transmitting layer 19C and the refractive index of the light emitting layer 14. The complex refractive index of the light transmitting layers 19B and 19C and the refractive index of the light emitting layer 14 can be measured using, for example, a spectroscopic ellipsometer.

  Although the details will be described later, the reflection conditions on the reflection surfaces S3 and S4 can be made different between the organic electroluminescent element 1 emitting red light and the organic electroluminescent element 1 emitting blue light. The light emission state can be adjusted for each light emission color of the light emitting element 1.

  By the reflection at the reflection surface S3, the light generated in the red light emitting layer 14 is weakened, and the half width of the spectrum is widened. Further, by the reflection at the reflection surface S4, the light generated in the red light emitting layer 14 is further weakened, and the half width of the spectrum is further widened. By making the vicinity of the peak of the spectrum gentle as described above, it is possible to suppress a sudden change in luminance and hue depending on the angle. Further, by the reflection on the reflection surface S4, the light generated in the blue light emitting layer 14 is strengthened, and the peak is increased. As described above, by giving a steep peak, light extraction efficiency can be increased. It is also possible to improve the chromaticity point. The position of the peak of the spectrum formed by the reflecting surfaces S1 and S2 may be matched with the position of the peak of the spectrum formed by the reflecting surfaces S3 and S4, or they may be shifted. When the position of the peak of the spectrum formed by the reflection surfaces S1 and S2 and the position of the peak of the spectrum formed by the reflection surfaces S3 and S4 are shifted, the wavelength band in which the effect of the resonator structure is obtained is expanded. And sharp changes in luminance and hue can be suppressed.

  The organic electroluminescent device 1 that emits green light has, for example, reflection surfaces S1 to S4 configured similarly to the organic electroluminescent device 1 that emits blue light. Specifically, the reflection surfaces S1 to S4 are configured to reinforce with respect to the center wavelength of the emission spectrum of the green light-emitting layer 14.

  Next, the operation and effect of the organic electroluminescent device 1 according to the present modification will be described.

  In this modification, the light emitted from the light emitting layer 14 is multiple-reflected between the reflection surface S1 and the reflection surface S4, and is extracted from the light extraction surface SDR. By the way, it is not easy to improve the light distribution characteristics in a general organic electroluminescent device.

  For example, a method has been proposed in which the film thickness between the light-transmitting electrode and the reflective electrode is set so that light of a desired wavelength resonates, thereby increasing the luminous efficiency (for example, International Publication WO 01/039554). No. pamphlet). Further, for example, attempts have been made to control the balance of attenuation of the three primary colors (red, green, and blue) by controlling the film thickness of the organic layer, and to enhance the viewing angle characteristics of the chromaticity point of white (for example, JP, 2011-159433, A).

  However, in these configurations, the stacked structure of the organic electroluminescent element functions as an interference filter having a narrow half-width with respect to the spectrum of the extracted light. Therefore, when the light extraction surface is viewed from an oblique direction, the wavelength of light shifts significantly. For this reason, the emission intensity is reduced depending on the viewing angle, and the viewing angle dependency is increased.

  For example, Japanese Patent Application Laid-Open No. 2006-244713 proposes a structure for reducing a change in hue due to a viewing angle. However, this structure may be applied to a single color and reduce the viewing angle dependence of luminance, but is difficult to apply to a sufficiently wide wavelength band. It is conceivable to increase the reflectivity in order to widen the applicable wavelength band, but in this case, the light extraction efficiency is significantly reduced.

  As described above, a method of reducing the angle dependency by adjusting the positional relationship and the light emitting position in the stacked structure of the organic electroluminescent element can be considered, but this method may make adjustment difficult. For example, there is a case where wavelength dispersion of the refractive index occurs due to the spectrum of light emitted from each light emitting layer. In the wavelength dispersion of the refractive index, since the refractive index of the constituent material varies depending on each wavelength, a difference occurs in the effect of the resonator structure among the red organic electroluminescent element, the green organic electroluminescent element, and the blue organic electroluminescent element. For example, in a red organic electroluminescent device, the peak of the extracted red light is too steep, and in a blue organic electroluminescent device, the peak of the extracted blue light is too gentle. As described above, if the effect of the resonator structure greatly differs for each element region, the angle dependence of luminance and hue increases, and the light distribution characteristics deteriorate.

  On the other hand, in this modification, the reflection surfaces S3 and S4 affect the light generated in the red light-emitting layer 14 and the reflection surfaces S3 and S4 affect the light generated in the blue light-emitting layer 14. Have different effects. Specifically, light generated in the red light emitting layer 14 and light generated in the blue light emitting layer 14 are as follows.

  Light generated in the red light emitting layer 14 is weakened by interference between the light emitting center 14a of the red light emitting layer 14 and the reflecting surfaces S3 and S4 of the red sub-pixel 22R. On the other hand, light generated in the blue light emitting layer 14 is enhanced by interference between the light emitting center 14a of the blue light emitting layer 14 and the reflection surfaces S3, S4 of the blue organic electroluminescent element 1.

  Thereby, in the red organic electroluminescent element 1, red light whose peak vicinity is gentle is extracted from the light extraction surface SDR, and in the blue organic electroluminescent element 1, blue light having a steep peak is extracted from the light extraction surface SDB. Taken out. Therefore, the difference between the effect of the resonator structure of the red organic electroluminescent element 1 and the effect of the resonator structure of the blue organic electroluminescent element 1 is reduced, and the angle dependence of luminance and hue is reduced. Therefore, the light distribution characteristics can be improved. Further, the organic electroluminescent device 2 having high light distribution characteristics is also suitable for a display device requiring high image quality, and can improve the productivity of the display device.

  In the organic electroluminescent device 1 according to this modification, even at a viewing angle of 45 °, Δuv ≦ 0.015 and a luminance of 60% or more can be maintained, and high image quality can be realized.

  As described above, in the organic electroluminescent element 1 according to the present modification, the reflection surfaces S3 and S4 of the red sub-pixel 22R are provided so as to weaken the light generated in the red light-emitting layer 14. On the other hand, the reflection surfaces S3 and S4 of the blue sub-pixel 22B are provided so as to enhance the light generated in the blue light emitting layer. Thus, the effect of the resonator structure can be adjusted for each sub-pixel 22, so that the light distribution characteristics can be improved.

  Further, high light transmittance can be obtained over a wide wavelength band, so that light extraction efficiency can be improved. As a result, power consumption can be reduced.

  When the reflecting surfaces S3 and S4 are formed by laminating metal thin films having a thickness of 5 nm or more, it is possible to obtain high light transmittance over a wide wavelength band.

  Further, the organic electroluminescent device 1 according to the present modification is suitable when the light emitting layer 14 is a printing layer. The thickness of the light emitting layer 14 is likely to vary depending on the region, for example, through a drying process. That is, a film thickness distribution easily occurs in the light emitting layer 14. In the organic electroluminescent element 1 according to the present modification, it is possible to adjust the difference in the effect of the resonator structure of each organic electroluminescent element 1 caused by the film thickness distribution.

<3. Second Embodiment>
[Constitution]
FIG. 16 illustrates a schematic configuration example of an organic electroluminescent device 2 according to the second embodiment of the present disclosure. FIG. 17 illustrates an example of a circuit configuration of a sub-pixel 22 included in each pixel 21 provided in the organic electroluminescent device 2. The organic electroluminescent device 2 includes, for example, an organic electroluminescent panel 20, a controller 30, and a driver 40. The driver 40 is mounted on, for example, an outer edge portion of the organic electroluminescent panel 20. The organic electroluminescent panel 20 has a plurality of pixels 21 arranged in a matrix. The controller 30 and the driver 40 drive the organic electroluminescent panel 20 (the plurality of pixels 21) based on the video signal Din and the synchronization signal Tin input from the outside.

(Organic electroluminescent panel 20)
The organic electroluminescent panel 20 displays an image based on the video signal Din and the synchronization signal Tin input from the outside by driving each pixel 21 by the active matrix driving by the controller 30 and the driver 40. The organic electroluminescent panel 20 includes a plurality of scanning lines WSL extending in a row direction, a plurality of signal lines DTL and a plurality of power supply lines DSL extending in a column direction, and a plurality of pixels 21 arranged in a matrix. have.

  The scanning line WSL is used for selecting each pixel 21 and supplies a selection pulse for selecting each pixel 21 for each predetermined unit (for example, a pixel row) to each pixel 21. The signal line DTL is used to supply a signal voltage Vsig corresponding to the video signal Din to each pixel 21, and supplies a data pulse including the signal voltage Vsig to each pixel 21. The power supply line DSL supplies power to each pixel 21.

  Each pixel 21 includes, for example, a sub-pixel 22 that emits red light, a sub-pixel 22 that emits green light, and a sub-pixel 22 that emits blue light. Note that each pixel 21 may further include, for example, a sub-pixel 22 that emits another color (for example, white or yellow). In each pixel 21, the plurality of sub-pixels 22 are arranged, for example, in a line in a predetermined direction.

  Each signal line DTL is connected to an output terminal of a horizontal selector 41 described later. For example, a plurality of signal lines DTL are assigned to each pixel column. Each scanning line WSL is connected to an output terminal of a write scanner 42 described later. For example, a plurality of scanning lines WSL are assigned to each pixel row one by one. Each power supply line DSL is connected to an output terminal of a power supply. For example, a plurality of power supply lines DSL are assigned to each pixel row.

  Each sub-pixel 22 has a pixel circuit 22-1 and an organic electroluminescent element 22-2. The organic electroluminescent element 22-2 is the organic electroluminescent element 1 according to the first embodiment, Modification A and Modification B.

  The pixel circuit 22-1 controls light emission and extinction of the organic electroluminescent element 22-2. The pixel circuit 22-1 has a function of holding a voltage written to each sub-pixel 22 by a write scan described later. The pixel circuit 22-1 includes, for example, a driving transistor Tr1, a writing transistor Tr2, and a storage capacitor Cs.

  The write transistor Tr2 controls application of a signal voltage Vsig corresponding to the video signal Din to the gate of the drive transistor Tr1. Specifically, the write transistor Tr2 samples the voltage of the signal line DTL, and writes the voltage obtained by the sampling to the gate of the drive transistor Tr1. The driving transistor Tr1 is connected in series to the organic electroluminescent element 22-2. The driving transistor Tr1 drives the organic electroluminescent element 22-2. The driving transistor Tr1 controls the current flowing through the organic electroluminescent element 22-2 according to the magnitude of the voltage sampled by the writing transistor Tr2. The storage capacitor Cs holds a predetermined voltage between the gate and the source of the driving transistor Tr1. The storage capacitor Cs has a role of holding the gate-source voltage Vgs of the drive transistor Tr1 constant during a predetermined period. Note that the pixel circuit 22-1 may have a circuit configuration in which various capacitors and transistors are added to the above-described 2Tr1C circuit, or may have a circuit configuration different from the above-described 2Tr1C circuit configuration. Good.

  Each signal line DTL is connected to an output terminal of a later-described horizontal selector 41 and a source or a drain of the write transistor Tr2. Each scanning line WSL is connected to an output terminal of a write scanner 42 described later and a gate of the write transistor Tr2. Each power supply line DSL is connected to a power supply circuit and the source or drain of the drive transistor Tr1.

  The gate of the writing transistor Tr2 is connected to the scanning line WSL. The source or the drain of the write transistor Tr2 is connected to the signal line DTL. The terminal of the source and drain of the write transistor Tr2 that is not connected to the signal line DTL is connected to the gate of the drive transistor Tr1. The source or the drain of the driving transistor Tr1 is connected to the power supply line DSL. A terminal of the source and drain of the driving transistor Tr1 that is not connected to the power supply line DSL is connected to the anode 11 of the organic electroluminescent element 21-2. One end of the storage capacitor Cs is connected to the gate of the drive transistor Tr1. The other end of the storage capacitor Cs is connected to a terminal on the organic electroluminescent element 21-2 side of the source and the drain of the driving transistor Tr1.

(Driver 40)
The driver 40 has, for example, a horizontal selector 41 and a write scanner 42. The horizontal selector 41 applies the analog signal voltage Vsig input from the controller 30 to each signal line DTL, for example, in response to (in synchronization with) the input of a control signal. The light scanner 42 scans the plurality of sub-pixels 22 in predetermined units.

(Controller 30)
Next, the controller 30 will be described. For example, the controller 30 performs a predetermined correction on a digital video signal Din input from the outside, and generates a signal voltage Vsig based on the video signal obtained thereby. The controller 30 outputs the generated signal voltage Vsig to the horizontal selector 41, for example. For example, the controller 30 outputs a control signal to each circuit in the driver 40 in response to (in synchronization with) a synchronization signal Tin input from the outside.

  Next, the organic electroluminescent device 22-2 will be described with reference to FIGS. 18, 19, 20, and 21. FIG. FIG. 18 illustrates a schematic configuration example of the organic electroluminescent panel 20. FIG. 19 illustrates a cross-sectional configuration example of the organic electroluminescent panel 20 of FIG. 14 taken along line AA (that is, a cross-sectional configuration example of the sub-pixel 22 (22R) in the row direction). FIG. 20 illustrates a cross-sectional configuration example of the organic electroluminescent panel 20 of FIG. 18 taken along the line BB (that is, a cross-sectional configuration example of the sub-pixel 22 (22R) in the column direction). FIG. 21 illustrates a cross-sectional configuration example of the organic electroluminescent panel 20 of FIG. 18 taken along line CC (that is, a cross-sectional configuration example of the sub-pixel 22 (22R) in the column direction). FIG. 20 shows a cross-sectional configuration example at a location avoiding a crosspiece 24B described later. FIG. 21 shows an example of a cross-sectional configuration at a location including the crosspiece 24B.

  The organic electroluminescent panel 20 has a plurality of pixels 21 arranged in a matrix. Each pixel 21 includes, for example, the sub-pixel 22 (22R) that emits red light, the sub-pixel 22 (22G) that emits green light, and the sub-pixel 22 (22B) that emits blue light, as described above. ing.

  The sub-pixel 22R includes an organic electroluminescent element 22-2 (22r) that emits red light. The sub-pixel 22G includes an organic electroluminescent element 22-2 (22g) that emits green light. The sub-pixel 22B includes an organic electroluminescent element 22-2 (22b) that emits blue light. The sub-pixels 22R, 22G, and 22B have, for example, a stripe arrangement. In each pixel 21, for example, sub-pixels 22R, 22G, and 22B are arranged in a row direction. Further, in each pixel row, for example, a plurality of sub-pixels 22 that emit light of the same color are arranged in the column direction.

  The organic electroluminescent panel 20 has a substrate 10. The substrate 10 includes, for example, a base material that supports the organic electroluminescent elements 22-2, the insulating layer 24, the line banks 23, and the like, and a wiring layer provided on the base material. The base material in the substrate 10 is formed of, for example, non-alkali glass, soda glass, non-fluorescent glass, phosphate glass, borate glass, quartz, or the like. The substrate in the substrate 10 may be formed of, for example, an acrylic resin, a styrene resin, a polycarbonate resin, an epoxy resin, polyethylene, polyester, a silicone resin, or alumina. For example, a pixel circuit 22-1 of each pixel 21 is formed in a wiring layer in the substrate 10.

  The organic electroluminescent panel 20 further has an insulating layer 24 on the substrate 10. The insulating layer 24 is for dividing each sub-pixel 22. The upper limit of the thickness of the insulating layer 24 is preferably within a range in which shape control is possible in manufacturing, from the viewpoint of controlling film thickness variation and bottom line width, and is preferably 10 μm or less. Further, the upper limit of the thickness of the insulating layer 24 is more preferably within a range capable of suppressing an increase in tact due to an increase in exposure time in an exposure step and suppressing a decrease in productivity in a mass production step. It is more preferred that: In addition, the lower limit of the thickness of the insulating layer 24 is determined by the resolution limit of the exposure apparatus and the material since the bottom line width needs to be supplemented to be approximately the same as the film thickness as the film thickness decreases. The lower limit of the thickness of the insulating layer 24 is preferably 1 μm or more when using a semiconductor stepper, and is preferably 2 μm or more when using a flat panel stepper and scanner. . Therefore, the thickness of the insulating layer 24 is preferably 1 μm or more and 10 μm or less, and more preferably 2 μm or more and 7 μm or less.

  The insulating layer 24 has a plurality of column regulating sections 24C and a plurality of row regulating sections 24D that partition each sub-pixel 22. Each column regulating portion 24C extends in the column direction, and each row regulating portion 24D extends in the row direction. The plurality of column restricting portions 24C extend in the column direction and are arranged in parallel in the row direction with a predetermined gap. The plurality of row restricting portions 24D extend in the row direction and are arranged in parallel in the column direction with a predetermined gap. The plurality of column restricting portions 24C and the plurality of row restricting portions 24D intersect (for example, orthogonally) with each other and have a grid-like layout. Each sub-pixel 22 is surrounded by two adjacent column restricting portions 24C and two adjacent row restricting portions 24D, and defines each sub-pixel 22.

  The insulating layer 24 has a plurality of (for example, two) crosspieces 24B extending in the column direction for each sub-pixel 22. The plurality of crosspieces 24B extend in the column direction and are arranged in parallel in the row direction with a predetermined gap therebetween. Furthermore, the insulating layer 24 is located in a region surrounded by two adjacent column regulating portions 24C and two adjacent row regulating portions 24D, and at an unformed portion of each bar portion 24B. , A plurality of (for example, three) slit-shaped openings 24A. At the bottom surface of each opening 24A, a surface of an anode 11 described later is exposed. Therefore, the holes supplied from the anode 11 exposed on the bottom surface of each opening 24A and the electrons supplied from the cathode 17 described later are recombined in the light emitting layer 14 described later, thereby forming the light emitting layer 14 described later. Luminescence occurs. Therefore, in the light emitting layer 14 described later, a region facing the opening 24A becomes the light emitting region 14A.

  Each cross section 24B may be formed so as to straddle two adjacent row regulating sections 24D as shown in FIGS. 18 to 21, for example, or as shown in FIGS. 22 to 24, for example. As described above, it may be formed at a position distant from two adjacent row regulating portions 24D. FIG. 22 illustrates a schematic configuration example of the organic electroluminescent panel 20. FIG. 23 illustrates a cross-sectional configuration example of the organic electroluminescent panel 20 of FIG. 22 taken along line BB (that is, a cross-sectional configuration example of the sub-pixel 22 (22R) in the column direction). FIG. 24 illustrates a cross-sectional configuration example of the organic electroluminescent panel 20 of FIG. 22 along the line CC (that is, a cross-sectional configuration example of the sub-pixel 22 (22R) in the column direction). Note that the cross-sectional configuration example of the organic electroluminescent panel 20 of FIG. 22 along the line AA (that is, the cross-sectional configuration example of the sub-pixel 22 (22R) in the row direction) is common to FIG. 19 described above.

  The height of the row restricting portion 24D is lower than the height of the column restricting portion 24C, for example, as shown in FIGS. At this time, the plurality of sub-pixels 22 arranged in the column direction are arranged in the band-shaped groove formed by the two left and right column restricting portions 24C of the sub-pixels 22. For example, the light emitting layer 14, the electron The transport layer 15 and the electron injection layer 16 are shared with each other. The plurality of sub-pixels 22 arranged in the column direction may share the hole injection layer 12, the hole transport layer 13, the light emitting layer 14, the electron transport layer 15, and the electron injection layer 16, for example. Note that the height of the row restricting portion 24D may be the same as the height of the column restricting portion 24C, for example, as shown in FIGS. 22 to 24 and FIG. At this time, each of the sub-pixels 22 is arranged in a depression formed by two adjacent column restricting portions 24C and two adjacent row restricting portions 24D. 14.

The cross section in the row direction of each opening 24A has, for example, a trapezoidal shape widened upward as shown in FIG. In addition, the cross section of each opening 24A in the column direction has, for example, a trapezoidal shape widened upward as shown in FIGS. That is, the side surface of each of the openings 24A has a reflector structure for raising light emitted from the light emitting layer 14 described later. Assuming that the refractive index of the sealing layer 18 is n ₁ and the refractive index of the insulating layer 24 is n ₂ , n ₁ and n ₂ satisfy the following equations (15) and (16). n ₂ is preferably 1.4 or more and 1.6 or less. Thereby, the efficiency of extracting light emitted from the light-emitting layer 14 described below to the outside is improved.
1.1 ≦ n ₁ ≦ 1.8 (15)
| N ₁ −n ₂ | ≧ 0.20 (16)

Further, the depth D of each opening 24A (that is, the thickness of the insulating layer 24), the opening width Wh on the upper surface side of the insulating layer 24, and the opening width WL on the upper surface side of the insulating layer 24 are represented by the following formula ( 17) and (18) are preferably satisfied.
0.5 ≦ WL / Wh ≦ 0.8 (17)
0.5 ≦ D / WL ≦ 2.0 (18)

  With such a shape and a refractive index condition, the light extraction efficiency from the light emitting layer 14 can be improved by the reflector structure with the opening 24A of the insulating layer 24. As a result, according to the studies by the inventors, it is possible to increase the luminance per sub-pixel 22 by 1.2 to 1.5 times as compared with the case where there is no reflector structure.

  The insulating layer 24 is formed of, for example, an insulating organic material. Examples of the insulating organic material include an acrylic resin, a polyimide resin, and a novolak type phenol resin. The insulating layer 24 is preferably made of, for example, an insulating resin having heat resistance and resistance to a solvent. The column regulating section 24C and the row regulating section 24D are formed by, for example, processing an insulating resin into a desired pattern by photolithography and development. The cross-sectional shape of the row regulating portion 24C is, for example, a forward tapered type as shown in FIG. The cross-sectional shape of the row restricting portion 24D is, for example, a forward tapered type as shown in FIG.

  In the present embodiment, the organic electroluminescent device 1 according to the first embodiment, the modified examples A and B is used for the organic electroluminescent device 22-2 of each sub-pixel 22. Thereby, the organic electroluminescent panel 20 and the organic electroluminescent device 2 having high light extraction efficiency can be realized.

<4. Modification of Second Embodiment>
In the second embodiment, each organic electroluminescent element 22-2 has the light distribution control layer 19 on the cathode 17 as shown in FIGS. 25, 26, and 27, for example. Is also good. FIG. 25 illustrates a cross-sectional configuration example of the organic electroluminescent panel 20 of FIG. 18 taken along line AA (that is, a cross-sectional configuration example of the sub-pixel 22 (22R) in the row direction). FIG. 26 illustrates a cross-sectional configuration example of the organic electroluminescent panel 20 of FIG. 18 taken along line BB (that is, a cross-sectional configuration example of the sub-pixel 22 (22R) in the column direction). FIG. 27 illustrates a cross-sectional configuration example of the organic electroluminescent panel 20 of FIG. 18 taken along line CC (that is, a cross-sectional configuration example of the sub-pixel 22 (22R) in the column direction).

  In the present modified example, the light distribution control layer 19 is provided, for example, between the cathode 17 and the sealing layer 18. The light distribution control layer 19 may be formed, for example, in contact with the entire surface of the cathode 17.

  In this modification, the effects of the reflecting surfaces S3 and S4 on the light generated in the red light emitting layer 14 and the effects of the reflecting surfaces S3 and S4 on the light generated in the blue light emitting layer 14 are described. Different from each other. Specifically, light generated in the red light emitting layer 14 and light generated in the blue light emitting layer 14 are as follows.

  Light generated in the red light emitting layer 14 is weakened by interference between the light emitting center 14a of the red light emitting layer 14 and the reflecting surfaces S3 and S4 of the red sub-pixel 22R. On the other hand, light generated in the blue light emitting layer 14 is enhanced by interference between the light emitting center 14a of the blue light emitting layer 14 and the reflection surfaces S3, S4 of the blue organic electroluminescent element 1.

  Thereby, in the red organic electroluminescent element 1, red light whose peak vicinity is gentle is extracted from the light extraction surface SDR, and in the blue organic electroluminescent element 1, blue light having a steep peak is extracted from the light extraction surface SDB. Taken out. Therefore, the difference between the effect of the resonator structure of the red organic electroluminescent element 1 and the effect of the resonator structure of the blue organic electroluminescent element 1 is reduced, and the angle dependence of luminance and hue is reduced. Therefore, the light distribution characteristics can be improved. Further, the organic electroluminescent device 2 having high light distribution characteristics is also suitable for a display device requiring high image quality, and can improve the productivity of the display device.

<5. Application example>
[Application example 1]
Hereinafter, an application example of the organic electroluminescent device 2 according to the second embodiment and its modification will be described. The organic electroluminescent device 2 according to the second embodiment and the modification thereof includes a television device, a digital camera, a notebook personal computer, a sheet-shaped personal computer, a portable terminal device such as a mobile phone, a video camera, and the like. The present invention can be applied to a display device of an electronic device in any field that displays a video signal input from the outside or a video signal generated internally as an image or a video.

  FIG. 28 is a perspective view of the appearance of the electronic device 3 according to the application example. The electronic device 3 is, for example, a sheet-shaped personal computer having a display surface 320 on a main surface of a housing 310. The electronic device 3 includes the organic electroluminescent device 2 according to the second embodiment and its modification on the display surface 320 of the electronic device 3. The organic electroluminescent device 2 according to the second embodiment and the modification thereof is arranged such that the organic electroluminescent panel 20 faces outward. In this application example, since the organic electroluminescent device 2 according to the second embodiment and the modification thereof is provided on the display surface 320, an electronic device 3 with high luminous efficiency can be realized.

[Application example 2]
Hereinafter, an application example of the organic electroluminescent element 22-2 according to the second embodiment and its modification will be described. The organic electroluminescent element 22-2 according to the second embodiment and the modified example thereof is applied to a light source of a lighting device in any field such as a desktop lighting device or a floor lighting device, or an indoor lighting device. It is possible to

  FIG. 29 illustrates an appearance of an indoor lighting device to which the organic electroluminescent element 22-2 according to the second embodiment and its modification is applied. This illuminating device includes, for example, an illuminating unit 410 configured to include one or a plurality of organic electroluminescent elements 22-2 according to the second embodiment and its modifications. The lighting units 410 are arranged on the ceiling 420 of the building at appropriate numbers and intervals. Note that the lighting unit 410 can be installed not only on the ceiling 420 but also on an arbitrary place such as a wall 430 or a floor (not shown) depending on the use.

  In these illumination devices, illumination is performed by the light from the organic electroluminescent element 22-2 according to the second embodiment and its modification. Thereby, a lighting device with high luminous efficiency can be realized.

  As described above, the present disclosure has been described with reference to the embodiments. However, the present disclosure is not limited to the embodiments, and can be variously modified. Note that the effects described in this specification are merely examples. The effects of the present disclosure are not limited to the effects described in this specification. The present disclosure may have effects other than those described herein.

Further, for example, the present disclosure can have the following configurations.
(1)
An anode, a light emitting layer and a cathode in this order, and a low refractive index layer lower than the refractive index of the light emitting layer, between the light emitting layer and the cathode, and at least one of the anode and the light emitting layer. An organic electroluminescent device comprising:
(2)
The organic electroluminescent device according to (1), wherein the low refractive index layer is disposed between the light emitting layer and the cathode, and is made of a material having an electron transporting property or an electron injecting property.
(3)
The organic electroluminescent device according to (1), wherein the low refractive index layer is disposed between the anode and the light emitting layer and is made of a material having a hole injecting property or a hole transporting property.
(4)
The organic electroluminescent device according to (2) or (3), wherein the low refractive index layer is made of a material having a refractive index larger than 0.3 and smaller than 1.7.
(5)
The organic electroluminescent device according to (3), wherein the low refractive index layer is made of a material having a refractive index of 0.75 or more and 1.4 or less.
(6)
The organic electroluminescent device according to (2) or (3), wherein the low refractive index layer is made of a material having a refractive index of 0.5 or more and 1.7 or less.
(7)
The organic electroluminescent device according to (3), wherein the low refractive index layer is made of a material having a refractive index of 0.5 or more and 1.5 or less.
(8)
With multiple pixels,
Each of the pixels has an organic electroluminescent element,
The organic electroluminescent device,
The organic electroluminescent element has an anode, a light emitting layer and a cathode in this order, and at least one of a refractive index of the light emitting layer between the light emitting layer and the cathode, and at least one between the anode and the light emitting layer. Organic electroluminescent panel having a lower refractive index layer than the lower.
(9)
The organic electroluminescent panel according to (8), wherein the low refractive index layer is shared by the pixels.
(10)
An organic electroluminescent panel, comprising a driving circuit for driving the organic electroluminescent panel,
The organic electroluminescent panel has a plurality of pixels,
Each of the pixels has an organic electroluminescent element,
The organic electroluminescent element has an anode, a light emitting layer and a cathode in this order, and at least one of a refractive index of the light emitting layer between the light emitting layer and the cathode, and at least one between the anode and the light emitting layer. An electronic device having a lower refractive index layer.

  DESCRIPTION OF SYMBOLS 1 ... Organic electroluminescent element, 2 ... Organic electroluminescent device, 3 ... Electronic equipment, 11 ... Anode, 12 ... Hole injection layer, 12A ... Metal oxide layer, 12B ... Organic material layer, 13 ... Hole transport layer, 14 ... Emission layer, 14A ... Emission region, 15 ... Electron transport layer, 16 ... Electron injection layer, 17 ... Cathode, 18 ... Sealing layer, 19 ... Light distribution control layer, 20 ... Organic electroluminescent panel, 21 ... Pixel, 22 , 22R, 22G, 22B: sub-pixel, 22-1: pixel circuit, 22-2: organic electroluminescent element, 23: line bank, 24: insulating layer, 24A: opening, 24B: beam, 24C: column regulation Unit, 24D: row regulating unit, 30: controller, 40: driver, 41: horizontal selector, 42: light scanner, 310: housing, 320: display surface, 410: lighting unit, 420: ceiling, 430: wall, Tr1 ... Driving transistor, Tr2 ... -Option transistor, Cs ... storage capacitor, DSL ... power supply line, DTL ... signal line, S1, S2, S3, S4 ... reflection interface, Vgs ... gate - source voltage, Vsig ... signal voltage, WSL ... select line.

The hole transport layer 13 has a function of transporting holes injected from the anode 11 to the light emitting layer 14. The hole transport layer 13 is made of, for example, a material (a hole transport material) having a function of transporting holes injected from the anode 11 to the light emitting layer 14. Examples of the hole-transporting material include, for example, arylamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, butadiene compounds, polystyrene derivatives, Application Benefits triphenylmethane derivatives, tetraphenyl benzene derivatives, or materials mentioned consisting of combinations. The difference in the HOMO (highest occupied molecular orbital) level of each material of the hole injection layer 12 and the hole transport layer 13 is preferably 0.5 eV or less in consideration of the hole injection property. .

The sealing layer 18 is formed on the cathode 17. The sealing layer 18 is formed, for example, in contact with the upper surface of the cathode 17. The sealing layer 1 8 is, for example, made of a resin material. As the resin material used for the sealing layer 1 8, for example, epoxy resins, and vinyl resins.

FIGS. 2A and 2B show simulation results of an organic electroluminescent device having a microcavity structure that generates secondary interference (second cavity) and emits light on the cathode side. . Here, in the comparative example, the anode, thickness of 200 n m, and composed of a material having a refractive index of 0.7, a hole injection layer, a thickness of 10 nm, made of a material having a refractive index of 1.7, a hole The transport layer was made of a material having a thickness of 180 nm and a refractive index of 1.7, and the light emitting layer 14 was made of a material having a thickness of 60 nm and a refractive index of 1.7. In the comparative example, the electron transport layer was further formed of a material having a thickness of 10 nm and a refractive index of 1.8, the electron injection layer was formed of a material having a thickness of 10 nm and a refractive index of 2.0, and the cathode was formed of a material having a thickness of 2.0. The sealing layer was made of a material having a thickness of 5 μm and a refractive index of 1.8. Meanwhile, in the embodiment, the anode 11, the thickness 200 n m, and composed of a material having a refractive index of 0.7, a hole injection layer 12, a thickness of 10 nm, made of a material having a refractive index of 1.7, a positive The hole transport layer 13 was made of a material having a thickness of 180 nm and a refractive index of 1.7, and the light emitting layer 14 was made of a material having a thickness of 60 nm and a refractive index of 1.7. In the embodiment, the electron transport layer 15 is further formed of a material having a thickness of 10 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a material having a thickness of 10 nm and a refractive index of 1.3, and a cathode 17 is formed. Was formed of a material having a thickness of 15 nm and a refractive index of 0.3, and the sealing layer 18 was formed of a material having a thickness of 5 μm and a refractive index of 1.8.

In Figure 3, the anode 11, the thickness 200 n m, and composed of a material having a refractive index of 0.3, a hole injection layer 12, formed of a low refractive index material having a thickness of 10 nm, the hole transport layer 13 The light emitting layer 14 was made of a material having a thickness of 220 nm and a refractive index of 1.7, and the light emitting layer 14 was made of a material having a thickness of 60 nm and a refractive index of 1.7. In FIG. 3, the electron transport layer 15 is formed of a material having a thickness of 10 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a thickness of 10 nm, and the cathode 17 is formed of a material having a thickness of 15 nm and a refractive index of The sealing layer 18 was made of a material having a thickness of 5 μm and a refractive index of 1.8.

In Figure 4, the anode 11, the thickness 200 n m, and composed of a material having a refractive index of 0.3, a hole injection layer 12, formed of a low refractive index material having a thickness of 10 nm, the hole transport layer 13 The light emitting layer 14 was formed of a material having a thickness of 180 nm and a refractive index of 1.7, and the light emitting layer 14 was formed of a material having a thickness of 60 nm and a refractive index of 1.7. In FIG. 4, the electron transport layer 15 is formed of a material having a thickness of 10 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a thickness of 10 nm, and the cathode 17 is formed of a material having a thickness of 15 nm and a refractive index of The sealing layer 18 was made of a material having a thickness of 5 μm and a refractive index of 1.8.

In Figure 5, the anode 11, the thickness 200 n m, and composed of a material having a refractive index of 0.3, a hole injection layer 12, formed of a low refractive index material having a thickness of 10 nm, the hole transport layer 13 The light emitting layer 14 was formed of a material having a thickness of 140 nm and a refractive index of 1.7, and the light emitting layer 14 was formed of a material having a thickness of 40 nm and a refractive index of 1.7. In FIG. 5, the electron transport layer 15 is formed of a material having a thickness of 10 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a thickness of 10 nm, and the cathode 17 is formed of a material having a thickness of 15 nm and a refractive index of The sealing layer 18 was made of a material having a thickness of 5 μm and a refractive index of 1.8.

FIGS. 6A and 6B show simulation results of an organic electroluminescent device having a microcavity structure that generates secondary interference (second cavity) and emits light on the anode side. . Here, in the comparative example, the anode, thickness of 200 n m, and composed of a material having a refractive index of 0.7, a hole injection layer, a thickness of 10 nm, made of a material having a refractive index of 1.7, a hole The transport layer was made of a material having a thickness of 20 nm and a refractive index of 1.7, and the light emitting layer 14 was made of a material having a thickness of 90 nm and a refractive index of 1.7. In the comparative example, the electron transport layer was further formed of a material having a thickness of 30 nm and a refractive index of 1.8, the electron injection layer was formed of a material having a thickness of 80 nm and a refractive index of 2.0, and the cathode was formed of a material having a thickness of 2.0. The sealing layer was made of a material having a thickness of 5 μm and a refractive index of 1.8. Meanwhile, in the embodiment, the anode 11, the thickness 200 n m, and composed of a material having a refractive index of 0.7, a hole injection layer 12, a thickness of 10 nm, made of a material of refractive index 1.3, a positive The hole transport layer 13 was made of a material having a thickness of 20 nm and a refractive index of 1.7, and the light emitting layer 14 was made of a material having a thickness of 90 nm and a refractive index of 1.7. In the embodiment, further, the electron transport layer 15 is formed of a material having a thickness of 30 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a material having a thickness of 80 nm and a refractive index of 2.0, and the cathode 17 is formed. Was formed of a material having a thickness of 15 nm and a refractive index of 0.3, and the sealing layer 18 was formed of a material having a thickness of 5 μm and a refractive index of 1.8.

In Figure 6, the anode 11, the thickness 200 n m, and composed of a material having a refractive index of 0.3, a hole injection layer 12, formed of a low refractive index material having a thickness of 10 nm, the hole transport layer 13 The light emitting layer 14 was formed of a material having a thickness of 30 nm and a refractive index of 1.7, and the light emitting layer 14 was formed of a material having a thickness of 120 nm and a refractive index of 1.7. In FIG. 6, the electron transport layer 15 is formed of a material having a thickness of 30 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a material having a thickness of 80 nm and a refractive index of 2.0, and the cathode 17 is formed. Was formed of a material having a thickness of 15 nm and a refractive index of 0.3, and the sealing layer 18 was formed of a material having a thickness of 5 μm and a refractive index of 1.8.

In Figure 7, the anode 11, the thickness 200 n m, and composed of a material having a refractive index of 0.3, a hole injection layer 12, formed of a low refractive index material having a thickness of 10 nm, the hole transport layer 13 The light emitting layer 14 was made of a material having a thickness of 90 nm and a refractive index of 1.7. In FIG. 7, the electron transport layer 15 is formed of a material having a thickness of 30 nm and a refractive index of 1.8, the electron injection layer 16 is formed of a material having a thickness of 80 nm and a refractive index of 2.0, and the cathode 17 is formed. Was formed of a material having a thickness of 15 nm and a refractive index of 0.3, and the sealing layer 18 was formed of a material having a thickness of 5 μm and a refractive index of 1.8.

In Figure 8, the anode 11, the thickness 200 n m, and composed of a material having a refractive index of 0.3, a hole injection layer 12, formed of a low refractive index material having a thickness of 10 nm, the hole transport layer 13 The light emitting layer 14 was made of a material having a thickness of 40 nm and a refractive index of 1.7. In FIG. 8, the electron transport layer 15 is made of a material having a thickness of 30 nm and a refractive index of 1.8, the electron injection layer 16 is made of a material having a thickness of 80 nm and a refractive index of 2.0, and a cathode 17 is formed. Was formed of a material having a thickness of 15 nm and a refractive index of 0.3, and the sealing layer 18 was formed of a material having a thickness of 5 μm and a refractive index of 1.8.

A reflection surface S3 is formed on the upper surface of the light transmission layer 19A due to a difference in refractive index between the light transmission layer 19A and a layer (light transmission layer 19B) in contact with the upper surface of the light transmission layer 19A. The reflection surface S3 is arranged at a position at an optical distance L3 from the light emission center 14a of the light emitting layer 14. In the organic electroluminescent device 1 that emits red light, the optical distance L3 is set so that light of the central wavelength λ1 (λ1R) of the emission spectrum of the light emitting layer 14 is weakened by interference between the reflection surface S3 and the light emission center 14a. Is set to In the organic electroluminescent device 1 that emits blue light, the optical distance L3 is such that light of the central wavelength λ1 (λ1B) of the emission spectrum of the light-emitting layer 14 is strengthened by interference between the reflection surface S3 and the light-emitting center 14a. Is set to Specifically, in the organic electroluminescent device 1 that emits red light, the optical distance L3 is configured to satisfy the following equations (7) and (8). In the organic electroluminescent device 1 that emits blue light, the optical distance L3 is configured to satisfy the following expressions (9) and (10). In the equations (7), (8), (9), and (10), the unit of L3, λ1, λ13 , and λ23 is nm.

A reflection surface S4 is formed on the upper surface of the light transmission layer 19B due to a difference in refractive index between the light transmission layer 19B and a layer (light transmission layer 19C) in contact with the upper surface of the light transmission layer 19B. The reflection surface S4 is arranged at a position at an optical distance L4 from the light emission center 14a of the light emitting layer 14. In the organic electroluminescent device 1 that emits red light, the optical distance L4 is set so that light of the center wavelength λ1 (λ1R) of the emission spectrum of the light emitting layer 14 is weakened by interference between the reflection surface S4 and the light emission center 14a. Is set to In the organic electroluminescent device 1 that emits blue light, the optical distance L4 is such that light of the central wavelength λ1 (λ1B) of the emission spectrum of the light-emitting layer 14 is strengthened by interference between the reflection surface S4 and the light-emitting center 14a. Is set to Specifically, in the organic electroluminescent device 1 that emits red light, the optical distance L4 is configured to satisfy the following expressions (11) and (12). In the organic electroluminescent device 1 that emits blue light, the optical distance L4 is configured to satisfy the following expressions (13) and (14). In the equations (11), (12), (13), and (14), the unit of L4, λ1, λ14 , and λ24 is nm.

Still further, the depth D of each opening 24A (i.e., the thickness of the insulating layer 24), the opening width Wh of the upper surface side of the insulating layer 24, the opening width WL of the lower surface side of the insulating layer 24 has the following formula It is preferable to satisfy (17) and (18).
0.5 ≦ WL / Wh ≦ 0.8 (17)
0.5 ≦ D / WL ≦ 2.0 (18)

Further, for example, the present disclosure can have the following configurations.
(1)
An anode, a light emitting layer and a cathode in this order, and a low refractive index layer lower than the refractive index of the light emitting layer, between the light emitting layer and the cathode, and at least one of the anode and the light emitting layer. An organic electroluminescent device comprising:
(2)
The organic electroluminescent device according to (1), wherein the low refractive index layer is disposed between the light emitting layer and the cathode, and is made of a material having an electron transporting property or an electron injecting property.
(3)
The organic electroluminescent device according to (1), wherein the low refractive index layer is disposed between the anode and the light emitting layer and is made of a material having a hole injecting property or a hole transporting property.
(4)
The organic electroluminescent device according to (2) or (3), wherein the low refractive index layer is made of a material having a refractive index larger than 0.3 and smaller than 1.7.
(5)
The organic electroluminescent device according to (3), wherein the low refractive index layer is made of a material having a refractive index of 0.75 or more and 1.4 or less.
(6)
The organic electroluminescent device according to (2) or (3), wherein the low refractive index layer is made of a material having a refractive index of 0.5 or more and 1.7 or less.
(7)
The organic electroluminescent device according to (3), wherein the low refractive index layer is made of a material having a refractive index of 0.5 or more and 1.5 or less.
(8)
With multiple pixels,
Each of the pixels has an organic electroluminescent element,
The organic electroluminescent device has an anode, a light-emitting layer and a cathode in this order, and at least one of a refractive index of the light-emitting layer between the light-emitting layer and the cathode, and at least one between the anode and the light-emitting layer. Organic electroluminescent panel having a lower refractive index layer than the lower.
(9)
The organic electroluminescent panel according to (8), wherein the low refractive index layer is shared by the pixels.
(10)
An organic electroluminescent panel, comprising a driving circuit for driving the organic electroluminescent panel,
The organic electroluminescent panel has a plurality of pixels,
Each of the pixels has an organic electroluminescent element,
The organic electroluminescent device has an anode, a light-emitting layer and a cathode in this order, and at least one of a refractive index of the light-emitting layer between the light-emitting layer and the cathode, and at least one between the anode and the light-emitting layer. An electronic device having a lower refractive index layer.

Claims (7)

An anode, a light emitting layer and a cathode in this order, and a low refractive index layer lower than the refractive index of the light emitting layer, between the light emitting layer and the cathode, and at least one of the anode and the light emitting layer. An organic electroluminescent device comprising: The organic electroluminescent device according to claim 1, wherein the low refractive index layer is disposed between the light emitting layer and the cathode, and is made of a material having an electron transporting property or an electron injecting property. The organic electroluminescent device according to claim 2, wherein the low refractive index layer is made of a material having a refractive index larger than 0.3 and smaller than 1.7. The organic electroluminescent device according to claim 2, wherein the low refractive index layer is made of a material having a refractive index of 0.5 or more and 1.7 or less. With multiple pixels,
Each of the pixels has an organic electroluminescent element,
The organic electroluminescent device has an anode, a light-emitting layer and a cathode in this order, and at least one of a refractive index of the light-emitting layer between the light-emitting layer and the cathode, and at least one between the anode and the light-emitting layer. Organic electroluminescent panel having a lower refractive index layer than the lower. The organic electroluminescent panel according to claim 5, wherein the low refractive index layer is shared by each of the pixels. An organic electroluminescent panel, comprising a driving circuit for driving the organic electroluminescent panel,
The organic electroluminescent panel has a plurality of pixels,
Each of the pixels has an organic electroluminescent element,
The organic electroluminescent device has an anode, a light-emitting layer and a cathode in this order, and at least one of a refractive index of the light-emitting layer between the light-emitting layer and the cathode, and at least one between the anode and the light-emitting layer. An electronic device having a lower refractive index layer.