JP6754733B2 - Organic electroluminescent devices, organic electroluminescent panels, organic electroluminescent devices and electronic devices - Google Patents

Description

The present disclosure relates to organic electroluminescent devices, organic electroluminescent panels, organic electroluminescent devices and electronic devices.

Various organic electroluminescent devices (organic electroluminescent displays) using an organic electroluminescent element have been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-072812

By the way, in an organic electroluminescent device, it is generally required to improve the element performance of an organic electroluminescent element. Therefore, it is desirable to provide an organic electroluminescent device capable of improving device performance, and an organic electroluminescent panel, an organic electroluminescent device, and an electronic device provided with such an organic electroluminescent device.

The organic electroluminescent device of the embodiment of the present disclosure includes an anode, an organic layer including a light emitting layer, and a cathode in this order. In the organic layer, the first organic layer between the light emitting layer and the anode has an absorption coefficient of 0. 0 1 or more 0. It contains a hole transport layer composed of materials of 06 or less. The light emitting layer has a light emitting center at a position recessed from the interface on the anode side of the light emitting layer by a thickness greater than 0 and 0.4 or less when the thickness of the light emitting layer is 1. There is. This organic electroluminescent device has a microcavity structure in which the position of the interface is a resonance point.

The organic electroluminescent panel of one embodiment of the present disclosure includes red pixels, green pixels, and blue pixels. Each of the red pixel, the green pixel, and the blue pixel has an organic electroluminescent element including an anode, an organic layer including a light emitting layer, and a cathode in this order. In the organic layer of at least one of the red pixel, the green pixel, and the blue pixel, the first organic layer between the light emitting layer and the anode has an absorption coefficient of 0. 0 1 or more 0. It contains a hole transport layer composed of materials of 06 or less. The light emitting layer in the pixel having the hole transport layer recedes from the interface on the anode side of the light emitting layer by a thickness greater than 0 and 0.4 or less when the thickness of the light emitting layer is 1. It has a light emitting center at the position where it is located. The organic electroluminescent device in the pixel having the hole transport layer has a microcavity structure in which the position of the interface is a resonance point.

The organic electroluminescent device of one embodiment of the present disclosure includes an organic electroluminescent panel and a drive circuit for driving the organic electroluminescent panel. The organic electroluminescent panel provided in this organic electroluminescent device has the same components as the above organic electroluminescent panel.

The electronic device of one embodiment of the present disclosure includes an organic electroluminescent device. The organic electroluminescent device provided in this electronic device has the same components as the above-mentioned organic electroluminescent device.

In the organic electroluminescent device, the organic electroluminescent panel, the organic electroluminescent device, and the electronic device according to the embodiment of the present disclosure, the thickness of the light emitting layer is determined from the interface which is the most affected by the quenching by the hole transport layer. The emission center is a position that is larger than 0 when it is set to 1 and retracted by a thickness of 0.4 or less. As a result, it is possible to suppress the decrease in strength due to the deviation from the resonance point while avoiding the influence of quenching by the hole transport layer.

According to the organic electroluminescent device, the organic electroluminescent panel, the organic electroluminescent device, and the electronic device according to the embodiment of the present disclosure, the strength due to the deviation from the resonance point while avoiding the influence of the extinction by the hole transport layer. Since the decrease in the amount of the organic electroluminescent device can be suppressed to a low level, the element performance of the organic electroluminescent element can be improved. The effects of the present disclosure are not necessarily limited to the effects described herein, and may be any of the effects described herein.

It is a figure which shows the schematic configuration example of the organic electroluminescent device which concerns on one Embodiment of this disclosure. It is a figure which shows the circuit configuration example of the sub-pixel included in each pixel of FIG. It is a figure which shows the schematic structure example of the organic electroluminescent panel of FIG. It is a figure which shows the cross-sectional composition example of the organic electroluminescent panel of FIG. 3 along the line AA. It is a figure which shows the cross-sectional composition example of the organic electroluminescent panel of FIG. 3 by line BB. It is a figure which shows an example of the profile of the light emitting region generated in an organic light emitting layer. It is a figure which shows an example of the profile of the light emitting region generated in an organic light emitting layer. It is a figure which shows an example of the profile of the light emitting region generated in an organic light emitting layer. It is a figure which shows an example of the profile of the light emitting region generated in an organic light emitting layer. It is a figure which shows typically the organic electroluminescent element of FIG. 4 for each sub-pixel. It is a figure which shows an example of the film thickness of each layer in the organic electroluminescent device of FIG. It is a figure which shows an example of the film thickness of each layer in the organic electroluminescent device which concerns on a comparative example. It is a figure which shows an example of the relationship between the degree of a cavity, and the light extraction intensity. It is a figure which shows an example of the relationship between the degree of a cavity, and the light extraction intensity. It is a figure which shows an example of the intensity map of an organic electroluminescent element. It is a figure which shows an example of the numerical value of the intensity map of FIG. It is a figure which shows an example of the relationship between the position of the light emitting center in the organic electroluminescent element of FIG. 7 and the light extraction intensity. It is a figure which shows an example of the relationship between the position of the light emitting center in the organic electroluminescent element which concerns on a comparative example, and light extraction intensity. It is a figure which shows an example of the relationship between the absorption coefficient of a hole transport layer, and the light extraction intensity. It is a figure which shows an example of the appearance of the electronic device provided with the organic electroluminescent device of this disclosure perspectively. It is a figure which shows an example of the appearance of the illuminating apparatus provided with the organic electroluminescent element of this disclosure perspectively.

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, components, arrangement positions of the components, connection forms, and the like shown in the following embodiments are examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present disclosure will be described as arbitrary components. It should be noted that each figure is a schematic view and is not necessarily exactly illustrated. Further, in each figure, the same reference numerals are given to substantially the same configurations, and duplicate description will be omitted or simplified.

<1. Embodiment>
[Constitution]
FIG. 1 shows a schematic configuration example of the organic electroluminescent device 1 according to the embodiment of the present disclosure. FIG. 2 shows an example of the circuit configuration of the sub-pixel 12 included in each pixel 11 provided in the organic electroluminescent device 1. The organic electroluminescent device 1 includes, for example, an organic electroluminescent panel 10, a controller 20, and a driver 30. The driver 30 is mounted on, for example, the outer edge portion of the organic electroluminescent panel 10. The organic electroluminescent panel 10 has a plurality of pixels 11 arranged in a matrix. The controller 20 and the driver 30 drive the organic electroluminescent panel 10 (plurality of pixels 11) based on the video signal Din and the synchronization signal Tin input from the outside.

(Organic electroluminescent panel 10)
The organic electroluminescent panel 10 displays an image based on the video signal Din and the synchronization signal Tin input from the outside by driving each pixel 11 in an active matrix by the controller 20 and the driver 30. The organic electroluminescent panel 10 is arranged in a matrix with a plurality of scanning lines WSL extending in the row direction, a plurality of signal line DTLs extending in the column direction, and a plurality of power supply lines DSL extending in the row direction. It has a plurality of pixels 11 that have been formed.

The scanning line WSL is used for selecting each pixel 11, and supplies a selection pulse for selecting each pixel 11 for each predetermined unit (for example, a pixel row) to each pixel 11. The signal line DTL is used to supply the signal voltage Vsig corresponding to the video signal Din to each pixel 11, and supplies a data pulse including the signal voltage Vsig to each pixel 11. The power line DSL supplies power to each pixel 11.

Each pixel 11 includes, for example, a sub-pixel 12 that emits red light, a sub-pixel 12 that emits green light, and a sub-pixel 12 that emits blue light. It should be noted that each pixel 11 may be further configured to include sub-pixels 12 that emit other colors (for example, white, yellow, etc.). In each pixel 11, the plurality of sub-pixels 12 are arranged in a line in a predetermined direction, for example.

Each signal line DTL is connected to the output end of the horizontal selector 31 described later. For example, a plurality of signal line DTLs are assigned to each pixel sequence. Each scanning line WSL is connected to the output end of the light scanner 32 described later. For example, a plurality of scanning lines WSL are assigned to each pixel row. Each power line DSL is connected to the output end of the power supply. For example, a plurality of power line DSLs are assigned to each pixel row.

Each sub-pixel 12 has a pixel circuit 12-1 and an organic electroluminescent element 12-2. The configuration of the organic electroluminescent device 12-2 will be described in detail later.

The pixel circuit 12-1 controls the light emission / quenching of the organic electroluminescent element 12-2. The pixel circuit 12-1 has a function of holding the voltage written to each sub-pixel 12 by the writing scan described later. The pixel circuit 12-1 includes, for example, a drive transistor Tr1, a write transistor Tr2, and a holding capacitance Cs.

The writing transistor Tr2 controls the application of the signal voltage Vsig corresponding to the video signal Din to the gate of the driving transistor Tr1. Specifically, the writing transistor Tr2 samples the voltage of the signal line DTL and writes the voltage obtained by the sampling to the gate of the driving transistor Tr1. The drive transistor Tr1 is connected in series with the organic electroluminescent element 12-2. The drive transistor Tr1 drives the organic electroluminescent element 12-2. The drive transistor Tr1 controls the current flowing through the organic electroluminescent element 12-2 according to the magnitude of the voltage sampled by the write transistor Tr2. The holding capacitance Cs holds a predetermined voltage between the gate and the source of the drive transistor Tr1. The holding capacitance Cs has a role of holding the gate-source voltage Vgs of the drive transistor Tr1 constant during a predetermined period. The pixel circuit 12-1 may have a circuit configuration in which various capacitances and transistors are added to the above-mentioned 2Tr1C circuit, or may have a circuit configuration different from the above-mentioned 2Tr1C circuit configuration. Good.

Each signal line DTL is connected to the output end of the horizontal selector 31 described later and the source or drain of the write transistor Tr2. Each scanning line WSL is connected to the output end of the light scanner 32 described later and the gate of the writing transistor Tr2. Each power line DSL is connected to the power 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 drain of the write transistor Tr2 is connected to the signal line DTL. Of the source and drain of the write transistor Tr2, the terminals not connected to the signal line DTL are connected to the gate of the drive transistor Tr1. The source or drain of the drive transistor Tr1 is connected to the power line DSL. Of the source and drain of the drive transistor Tr1, terminals that are not connected to the power supply line DSL are connected to the anode 21 of the organic electroluminescent element 21-2. One end of the holding capacitance Cs is connected to the gate of the drive transistor Tr1. The other end of the holding capacitance Cs is connected to the terminal on the organic electroluminescent element 21-2 side of the source and drain of the drive transistor Tr1.

(Driver 30)
The driver 30 has, for example, a horizontal selector 31 and a light scanner 32. The horizontal selector 31 applies, for example, an analog signal voltage Vsig input from the controller 20 to each signal line DTL in response to (synchronously) input of a control signal. The light scanner 32 scans a plurality of sub-pixels 12 in predetermined units.

(Controller 20)
Next, the controller 20 will be described. For example, the controller 20 performs a predetermined correction on the digital video signal Din input from the outside, and generates a signal voltage Vsig based on the video signal obtained thereby. The controller 20 outputs, for example, the generated signal voltage Vsig to the horizontal selector 31. For example, the controller 20 outputs a control signal to each circuit in the driver 30 in response to (synchronously) the synchronization signal Tin input from the outside.

Next, the organic electroluminescent device 12-2 will be described with reference to FIGS. 3, 4, and 5. FIG. 3 shows a schematic configuration example of the organic electroluminescent panel 10. FIG. 4 shows an example of cross-sectional configuration of the organic electroluminescent panel 10 of FIG. 3 taken along the line AA. FIG. 5 shows an example of cross-sectional configuration of the organic electroluminescent panel 10 of FIG. 3 taken along the line BB.

The organic electroluminescent panel 10 has a plurality of pixels 11 arranged in a matrix. As described above, each pixel 11 includes, for example, a sub-pixel 12 (12R) that emits red light, a sub-pixel 12 (12G) that emits green light, and a sub-pixel 12 (12B) that emits blue light. ing. The sub-pixel 12R corresponds to a specific example of the "red pixel" of the present disclosure. The sub-pixel 12G corresponds to a specific example of the "green pixel" of the present disclosure. The sub-pixel 12B corresponds to a specific example of the "blue pixel" of the present disclosure.

The sub-pixel 12R includes an organic electroluminescent element 12-2 (12r) that emits red light. The sub-pixel 12G includes an organic electroluminescent element 12-2 (12 g) that emits green light. The sub-pixel 12B includes an organic electroluminescent element 12-2 (12b) that emits blue light. The sub-pixels 12R, 12G, and 12B have, for example, a striped arrangement. In each pixel 11, for example, sub-pixels 12R, 12G, and 12B are arranged side by side in the column direction. Further, in each pixel row, for example, a plurality of sub-pixels 12 that emit light of the same color are arranged side by side in the row direction.

The organic electroluminescent panel 10 has a plurality of line banks 13 extending in the row direction and a plurality of banks 15 extending in the column direction on the substrate 14. The plurality of line banks 13 and the plurality of banks 15 partition each sub-pixel 12R. The plurality of line banks 13 partition each sub-pixel 12 in each pixel 11. The plurality of banks 15 partition each pixel 11 in each pixel row. That is, the plurality of sub-pixels 12 are partitioned by the plurality of line banks 13 and the plurality of banks 15. Each bank 15 is provided between two line banks 13 adjacent to each other in the row direction. Both ends of each bank 15 are connected to two line banks 13 adjacent to each other in the column direction.

The substrate 14 is composed of, for example, a base material that supports each organic electroluminescent element 12-2, each line bank 13, and the like, and a wiring layer provided on the base material. The base material in the substrate 14 is formed of, for example, non-alkali glass, soda glass, non-fluorescent glass, phosphoric acid-based glass, boric acid-based glass, quartz, or the like. The base material in the substrate 14 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 12-1 of each pixel 11 is formed in the wiring layer in the substrate 14.

The line banks 13 and 15 are made of, for example, an insulating organic material. Examples of the insulating organic material include acrylic resin, polyimide resin, novolak type phenol resin and the like. The line banks 13 and banks 15 are preferably formed of, for example, an insulating resin having heat resistance and resistance to a solvent. The line banks 13 and 15 are formed, for example, by processing an insulating resin into a desired pattern by photolithography and development. The cross-sectional shape of the line bank 13 may be, for example, a forward taper type as shown in FIG. 4, or a reverse taper type having a narrow hem.

The region surrounded by the two line banks 13 parallel to each other and adjacent to each other and the banks 15 at both ends is the groove portion 16. In each sub-pixel 12, each organic electroluminescent element 12-2 is arranged one by one in the gap between two line banks 13 parallel to each other and adjacent to each other. That is, in each sub-pixel 12, each organic electroluminescent element 12-2 is arranged one by one in the groove 16.

Each organic electroluminescent device 12-2 has, for example, an anode 21, a hole injection layer 22, a hole transport layer 23, an organic light emitting layer 24, an electron transport layer 25, an electron injection layer 26, and a cathode 27 from the substrate 14 side. It is prepared in order. Of the hole injection layer 22 and the hole transport layer 23, at least the hole transport layer 23 corresponds to a specific example of the “first organic layer” of the present disclosure. The organic light emitting layer 24 corresponds to a specific example of the "light emitting layer" of the present disclosure. Of the electron transport layer 25 and the electron injection layer 26, at least the electron transport layer 25 corresponds to a specific example of the “second organic layer” of the present disclosure. The hole injection layer 22 is a layer for increasing the hole injection efficiency. The hole transport layer 23 is a layer for transporting the holes injected from the anode 21 to the organic light emitting layer 24. The organic light emitting layer 24 is a layer that emits light of a predetermined color by recombination of electrons and holes. The electron transport layer 25 is a layer for transporting electrons injected from the cathode 27 to the organic light emitting layer 24. The electron injection layer 26 is a layer for increasing the electron injection efficiency. At least one of the hole injection layer 22 and the electron injection layer 26 may be omitted. Each organic electroluminescent device 12-2 may further have a layer other than the above.

The anode 21 is formed on, for example, the substrate 14. The anode 21 is a transparent electrode having translucency, and for example, a transparent conductive film made of a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) is used. The anode 21 is not limited to the transparent electrode, and may be, for example, aluminum (Al), silver (Ag), an alloy of aluminum or silver, or a reflective electrode having reflectivity. The anode 21 may be a stack of a reflective electrode and a transparent electrode.

The hole transport layer 23 has a function of transporting the holes injected from the anode 21 to the organic light emitting layer 24. The hole transport layer 23 is, for example, a coating film. The hole transport layer 23 is formed, for example, by applying and drying a solution containing a hole transporting organic material (hereinafter, referred to as “hole transporting material 23M”) as a main component of the solute. There is. The hole transport layer 23 is configured to contain the hole transport material 23M as a main component. Further, the hole transporting material 12M, which is a solute, has a function of insolubilizing. The insolubilizing function refers to a function in which an insolubilizing group such as a crosslinkable group or a thermally dissociable soluble group is chemically changed by irradiation with heat or ultraviolet light or a combination thereof, and is insolubilized in an organic solvent or water. Therefore, the hole transport layer 12 is an insolubilized hole transport layer.

The hole transporting material 23M, which is a raw material (material) of the hole transporting layer 23, includes, for example, an arylamine derivative, a triazole derivative, an oxadiazole derivative, an imidazole derivative, a polyarylalkane derivative, a pyrazoline derivative and a pyrazolone derivative, and a phenylenediamine. Derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stillben derivatives, butadiene compounds, polystyrene derivatives, hydrazone derivatives, triphenylmethane derivatives, tetraphenylbenzine derivatives, etc., or combinations thereof. It is a material. The hole transporting material 23M further comprises soluble groups and insolubilizing groups such as thermally dissociable soluble groups, crosslinkable groups or desorbing protecting groups in its molecular structure, for example due to its soluble and insolubilizing functions. And have.

The organic light emitting layer 24 has a function of emitting light of a predetermined color by recombination of holes and electrons. The organic light emitting layer 24 is, for example, a coating film. The organic light emitting layer 24 is formed by applying and drying a solution containing an organic material (hereinafter, referred to as “organic light emitting material 24M”) that emits light by generating excitons by recombination of holes and electrons as a main component of the solute. It is formed. The organic light emitting layer 24 is configured to contain the organic light emitting material 24M as a main component. In the organic electroluminescent element 12r included in the sub-pixel 12R, the organic luminescent material 24M is configured to include the red organic luminescent material. In the organic electroluminescent element 12g included in the sub-pixel 12G, the organic luminescent material 24M is configured to include the green organic luminescent material. In the organic electroluminescent element 12b included in the sub-pixel 12B, the organic luminescent material 24M is configured to include the blue organic luminescent material.

The organic light emitting layer 24 is composed of, for example, a single organic light emitting layer or a plurality of laminated organic light emitting layers. When the organic light emitting layer 24 is composed of a plurality of organic light emitting layers laminated, the organic light emitting layer 24 is, for example, a stack of a plurality of organic light emitting layers having a common main component. At this time, the plurality of organic light emitting layers are both coating films. Both of the plurality of organic light emitting layers are formed by applying and drying a solution containing the organic light emitting material 24M as a main component of the solute.

The organic light emitting material 24M, which is a raw material (material) of the organic light emitting layer 24, may be, for example, a dopant material alone, but more preferably a combination of a host material and a dopant material. That is, it is preferable that the organic light emitting layer 24 is configured to include a host material and a dopant material as the organic light emitting material 24M. The host material is mainly responsible for electron or hole charge transport, and the dopant material is responsible for light emission. The host material and the dopant material are not limited to only one type, and may be a combination of two or more types. The amount of the dopant material is preferably 0.01% by weight or more and 30% by weight or less, and more preferably 0.01% by weight or more and 10% by weight or less with respect to the host material.

As the host material of the organic light emitting layer 24, for example, an amine compound, a condensed polycyclic aromatic compound, and a heterocyclic compound are 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 anthracene derivatives, naphthalene derivatives, naphthalene derivatives, phenanthrene derivatives, chrysene derivatives, fluoranthene derivatives, triphenylene derivatives, pentacene derivatives, perylene derivatives and the like. Examples of the heterocyclic compound include carbazole derivatives, furan derivatives, pyridine derivatives, pyrimidine derivatives, triazine derivatives, imidazole derivatives, pyrazole derivatives, triazole derivatives, oxazole derivatives, oxaziazole derivatives, pyrrole derivatives, indole derivatives, and azaindole derivatives. Examples thereof include azacarbazole, pyrazoline derivatives, pyrazolone derivatives, and phthalocyanine derivatives.

Further, as the dopant material of the organic light emitting layer 24, for example, a pyrene derivative, a fluorantene derivative, an arylacetylene derivative, a fluorene derivative, a perylene derivative, an oxadiazole derivative, an anthracene derivative, or a chrysene derivative is used. Further, as the dopant material of the organic light emitting layer 24, a metal complex may be used. Examples of the metal complex include those having a metal atom such as iridium (Ir), platinum (Pt), osmium (Os), gold (Au), renium (Re), or ruthenium (Ru) and a ligand. Can be mentioned.

In the organic electroluminescent element 12r included in the sub-pixel 12R, the organic light emitting material 24M is composed of an organic light emitting material having an electron mobility larger than that of the hole mobility. That is, the organic electroluminescent material 24M contained in the organic electroluminescent device 12r is a material having high electron transportability and having an electron mobility larger than that of the hole mobility. Therefore, in the organic electroluminescent device 12r, the light emitting region 12A is located on the hole transport layer 23 side. In the organic electroluminescent device 12r, the light emitting region 12A may be located near the interface with the hole transport layer 23.

In the organic electroluminescent element 12g included in the sub-pixel 12G, the organic luminescent material 24M is composed of an organic luminescent material having an electron mobility larger than that of the hole mobility. That is, the organic electroluminescent material 24M contained in the organic electroluminescent device 12g is a material having high electron transportability and having an electron mobility larger than that of the hole mobility. Therefore, in the organic electroluminescent device 12g, the light emitting region 12A is located on the hole transport layer 23 side. In the organic electroluminescent device 12g, the light emitting region 12A may be located near the interface with the hole transport layer 23.

In the organic electroluminescent device 12 b included in the sub-pixel 12B, the organic light emitting material 24M, the hole mobility is constituted by a large organic light emitting material than the electron mobility. That is, the organic electroluminescent material 24M contained in the organic electroluminescent device 12b is a material having high hole transportability and having a hole mobility higher than the electron mobility. Therefore, in the organic electroluminescent device 12b, the light emitting region 12A is located on the electron transport layer 25 side. In the organic electroluminescent device 12b, the light emitting region 12A may be located near the interface with the electron transport layer 25.

“The light emitting region 12A is located on the electron transporting layer 25 side” means that, for example, as shown in FIG. 6A, the electron transporting layer 25 is arranged in 50% or more of the light emitting region 12A in the organic light emitting layer 24. It means that it exists in the area on the side of being. “The light emitting region is located on the hole transport layer 23 side” means that, for example, as shown in FIG. 6B, the hole transport layer 23 is arranged in 50% or more of the light emitting region 12A in the organic light emitting layer 24. It means that it exists in the area of the side.

"The light emitting region 12A is located near the interface with the electron transport layer 25" means that, for example, as shown in FIG. 6C, 90% or more of the light emitting region 12A in the organic light emitting layer 24 is the electron transport layer 25. It means that it exists on the side where it is placed. “The light emitting region 12A is located near the interface with the hole transport layer 23” means that, for example, as shown in FIG. 6D, 90% or more of the light emitting region 12A in the organic light emitting layer 24 is the hole transport layer. It means that 23 exists in the area on the side where it is arranged. An example of the light emitting region 12A is shown in FIGS. 6A to 6D. For example, the peak of the light emitting region (light emitting center 12a) may be located in the organic light emitting layer 24 instead of the interface of the organic light emitting layer 24. As a method of changing the profile of the light emitting region 12A and the position of the peak (light emitting center 12a), for example, there is a method of adjusting the ratio of the host material and the dopant material contained in the organic light emitting layer 24.

The electron transport layer 25 has a function of transporting electrons injected from the cathode 27 to the organic light emitting layer 24. The electron transport layer 25 is, for example, a vapor deposition film or a sputter film. The electron transport layer 25 is composed of an organic material having an electron transport property (hereinafter, referred to as “electron transport material 25M”) as a main component. The electron transport layer 25 is preferably made of an organic material having a wide energy gap, which is suitable for hole blocking and preventing exciton deactivation. The electron transport layer 25 is made of an organic material in which the energy gap of the electron transport layer 25 is larger than the energy gap of the organic light emitting layer 24.

The energy gap refers to the energy difference between the HOMO (Highest occupied molecular orbital) energy level and the LUMO (Lowest unoccupied molecular orbital) energy level. The energy gap is also called the band gap. Examples of the method for measuring the HOMO level include atmospheric photoelectron spectroscopy, electrochemical method (cyclic voltammetry), photoelectron spectroscopy (PES), and the like. On the other hand, as a method for measuring the LUMO level, for example, a method of calculating from the energy gap obtained from the absorption edge by the back light electron spectroscopy (IPES) or the light absorption spectroscopy and the HOMO level can be mentioned. In addition, a method of calculating the HOMO level and the LUMO level rank may be used for each level by using the molecular activation method calculation.

The electron transport layer 25 is interposed between the organic light emitting layer 24 and the cathode 27, and has a function of transporting electrons injected from the cathode 27 to the organic light emitting layer 24. The electron transport layer 25 further suppresses a charge blocking function that suppresses the penetration of charges (holes in the present embodiment) from the organic light emitting layer 24 to the cathode 27 and quenching of the excited state of the organic light emitting layer 24. It is preferable that it has a function of performing. The electron-transporting material 25M, which is a raw material (material) of the electron-transporting layer 25, is, for example, an aromatic heterocyclic compound containing one or more heteroatoms in the molecule. Examples of the aromatic heterocyclic compound include compounds having a pyridine ring, a pyrimidine ring, a triazine ring, a benzimidazole ring, a phenanthroline ring, a quinazoline ring, and the like in the skeleton. Further, the electron transport layer 25 may contain a metal having an electron transport property. Since the electron transport layer 25 contains a metal having an electron transport property, the electron transport property of the electron transport layer 25 can be improved. Examples of the metal contained in the electron transport layer 25 include barium (Ba), lithium (Li), calcium (Ca), potassium (K), cesium (Cs), sodium (Na), rubidium (Rb), and ytterbium (itribium). Yb) and the like can be used.

The cathode 27 is, for example, a reflective electrode having light reflectivity, for example, a metal electrode formed by using a metal material having reflectivity. As the material of the cathode 27, for example, aluminum (Al), magnesium (Mg), silver (Ag), aluminum-lithium alloy, magnesium-silver alloy and the like are used. The cathode 27 is not limited to the reflective electrode, and may be a transparent electrode such as an ITO film, like the anode 21. When the substrate 14 and the anode 21 are translucent and the cathode 27 is reflective, the organic electroluminescent element 12-2 has a bottom emission structure in which light is emitted from the substrate 14 side. When the anode 21 is reflective and the cathode 27 is translucent, the organic electroluminescent device 12-2 has a top emission structure.

The organic electroluminescent panel 10 may further have, for example, a sealing layer 28 that seals each organic electroluminescent element 12-2. The sealing layer 28 is provided, for example, in contact with the surface of the cathode 27 of each organic electroluminescent element 12-2.

Next, the features of the organic electroluminescent device 12-2 according to the present embodiment will be described with reference to comparative examples. FIG. 7 schematically shows the organic electroluminescent element 12-2 for each type of sub-pixel 12. FIG. 8 shows an example of the film thickness of each layer in the organic electroluminescent device 12-2 of FIG. FIG. 9 shows an example of the film thickness of each layer in the organic electroluminescent device according to the comparative example. 10 and 11 show an example of the relationship between the order of the cavity and the light extraction intensity. FIG. 12 shows an example of the intensity map of the organic electroluminescent device 12-2. FIG. 12A shows an example of the intensity map of the organic electroluminescent device 12-2 of the red sub-pixel 12R. FIG. 12B shows an example of the intensity map of the organic electroluminescent device 12-2 of the green sub-pixel 12R. FIG. 12C shows an example of the intensity map of the organic electroluminescent device 12-2 of the blue sub-pixel 12R. FIG. 13 shows an example of the numerical values of the intensity map of FIG.

In the sub-pixel 12R, sub-pixel 12G, and sub-pixel 12B, the organic electroluminescent element 12-2 is provided with a microcavity structure. At the left end of FIG. 7, the microcavity structure Cr provided in the organic electroluminescent element 12-2 of the sub-pixel 12R is illustrated. In the center of FIG. 7, the microcavity structure Cg provided in the organic electroluminescent device 12-2 of the sub-pixel 12G is illustrated. In the microcavity structures Cr and Cg of FIG. 7, the layer composed of the hole injection layer 22 and the hole transport layer 23 corresponds to a specific example of the “first organic layer” of the present disclosure. In the microcavity structures Cr and Cg of FIG. 7, the layer composed of the electron transport layer 25 and the electron injection layer 26 corresponds to a specific example of the “second organic layer” of the present disclosure. In addition, in FIG. 7, the hole injection layer 22 may be omitted. Further, in FIG. 7, the electron injection layer 26 may be omitted. Further, in the microcavity structures Cr and Cg of FIG. 7, when all or a part of the hole injection layer 22 is made of an inorganic material, the layer composed of the hole injection layer 22 and the hole transport layer 23. Of these, the portion composed of the organic material corresponds to a specific example of the "first organic layer" of the present disclosure. At the right end of FIG. 7, a microcavity structure Cb provided in the organic electroluminescent element 12-2 of the sub-pixel 12B is illustrated. The microcavity structures Cr, Cg, and Cb have an effect of enhancing light of a specific wavelength by utilizing, for example, the resonance of light generated between the anode 21 and the cathode 27. The light emitted from the organic light emitting layer 24 is multiplex reflected between the anode 21 and the cathode 27. At this time, a specific wavelength component of the light emitted from the organic light emitting layer 24 is strengthened.

In the present embodiment, the wavelengths of the light emitted from the sub-pixel 12R, the sub-pixel 12G, and the sub-pixel 12B are different from each other. Therefore, the optical path length between the anode 21 and the cathode 27 corresponds to the emission spectrum peak wavelength of each color. The light emitted from the organic light emitting layer 24 due to the microcavity structures Cr, Cg, and Cb is repeatedly reflected between the anode 21 and the cathode 27 within a predetermined optical length range, and has a specific wavelength corresponding to the optical path length. Light resonates and is enhanced, while light with a wavelength that does not correspond to the optical path length is weakened. As a result, the spectrum of light taken out to the outside becomes steep and high in intensity, and the brightness and color purity are improved.

In the microcavity structure, as the film thickness increases, primary interference (first cavity), secondary interference (second cavity), tertiary interference (third cavity), and the like occur. The microcavity structures Cr and Cg have an optical path length at which a second cavity is generated. On the other hand, the microcavity structure Cb has an optical path length at which a third cavity is generated. In the microcavity structure Cr, the distance Lr between the anode 21 and the cathode 27 is the optical path length at which the second cavity is generated at the wavelength of the light (red light) emitted from the organic light emitting layer 24 of the sub-pixel 12R. Further, in the microcavity structure Cg, the distance Lg between the anode 21 and the cathode 27 becomes the optical path length at which the second cavity is generated at the wavelength of the light (green light) emitted from the organic light emitting layer 24 of the sub-pixel 12G. There is. Further, in the microcavity structure Cb, the distance Lg between the anode 21 and the cathode 27 is the optical path length at which the third cavity is generated at the wavelength of the light (blue light) emitted from the organic light emitting layer 24 of the sub-pixel 12B. There is.

In the present embodiment, in the sub-pixel 12R, the sub-pixel 12G, and the sub-pixel 12B, the electron transport layer 25 is composed of layers common to each other. For example, in the sub-pixel 12R, the sub-pixel 12G, and the sub-pixel 12B, the electron transport layer 25 is collectively formed by vapor deposition, sputtering, or the like. In the sub-pixel 12R and the sub-pixel 12G, the hole injection layer 22, the hole transport layer 23, the organic light emitting layer 24, the electron transport layer 25 and the electron injection layer 26 are the distances between the anode 21 and the cathode 27 Lr, Lg. However, the film thickness is adjusted so as to have the optical path length at which the second cavity is generated. Further, in the sub-pixel 12B, the hole injection layer 22, the hole transport layer 23, the organic light emitting layer 24, the electron transport layer 25 and the electron injection layer 26 have a third cavity having a distance Lb between the anode 21 and the cathode 27. The film thickness is adjusted so that the optical path length is such that

In the design of the organic electroluminescent device, the distance between the anode 21 and the light emitting center 24a and the distance between the cathode 27 and the light emitting center 24a are very important. Strictly speaking, the reference point of these distances is the position where luminescence recombination occurs.

In FIG. 8, in the sub-pixel 12R and the sub-pixel 12G, the light emitting center 24a is located on the hole transport layer 23 side in the organic light emitting layer 24, and in the sub pixel 12B, the light emitting center 24a is the electron transport in the organic light emitting layer 24. An example of the thickness of each layer when it is located on the layer 25 side is shown. In FIG. 8, the unit of film thickness is nm. In the upper part of FIG. 8, in the microcavity structure Cr, the ideal film thickness of the portion (upper layer) corresponding to the upper part of the light emitting center 24a and the ideal portion (lower layer) corresponding to the lower part of the light emitting center 24a. The film thickness is exemplified.

In the sub-pixel 12R, the film thickness Lr1 of the upper layer is ideally 250 nm, and the film thickness Lr2 of the lower layer is ideally 60 nm. The film thickness Lr1 corresponds to a specific example of the "second distance" of the present disclosure, and the film thickness Lr2 corresponds to a specific example of the "first distance" of the present disclosure. The film thicknesses Lr1 and Lr2 have optical path lengths such that the light emitted from the light emitting center 24a resonates with the microcavity structure Cr. Further, in the sub-pixel 12G, the film thickness Lg1 of the upper layer is ideally 215 nm, and the film thickness Lg2 of the lower layer is ideally 50 nm. The film thicknesses Lg1 and Lg2 have optical path lengths such that the light emitted from the light emitting center 24a resonates with the microcavity structure Cg. The film thickness Lg1 corresponds to a specific example of the "second distance" of the present disclosure, and the film thickness Lg2 corresponds to a specific example of the "first distance" of the present disclosure. In the sub-pixel 12B, the film thickness Lb1 of the upper layer is ideally 170 nm, and the film thickness Lb2 of the lower layer is ideally 180 nm. The film thicknesses Lb1 and Lb2 have optical path lengths such that the light emitted from the light emitting center 24a resonates with the microcavity structure Cb.

Further, in the lower part of FIG. 8, the film thickness of each layer included in the organic electroluminescent device 12-2 is illustrated. In each sub-pixel 12, the electron transport layer 25 and the electron injection layer 24 are collectively formed by vapor deposition, sputtering, or the like, and the total film thickness of the electron transport layer 25 and the electron injection layer 24 is 170 nm. .. In the sub-pixel 12r, the film thickness of the organic light emitting layer 24 is 80 nm, and the total film thickness of the hole transport layer 23 and the hole injection layer 22 is 60 nm. Further, in the sub-pixel 12g, the film thickness of the organic light emitting layer 24 is 45 nm, and the total film thickness of the hole transport layer 23 and the hole injection layer 22 is 50 nm. Further, in the sub-pixel 12b, the film thickness of the organic light emitting layer 24 is 50 nm, and the total film thickness of the hole transport layer 23 and the hole injection layer 22 is 130 nm.

From FIG. 8, in each sub-pixel 12, the film thickness of the organic light emitting layer 24 is a film thickness suitable for coating (45 nm to 80 nm), and further, a total film of the hole transport layer 23 and the hole injection layer 22. It can be seen that the thickness is also a film thickness (50 nm to 130 nm) suitable for coating.

FIG. 9 illustrates the film thickness of each sub-pixel according to the comparative example. FIG. 9 shows an example of the film thickness of each layer when the emission center is located on the hole transport layer side in the organic light emitting layer in the sub-pixels of each color. In FIG. 9, the unit of film thickness is nm. In the upper part of FIG. 9, in the microcavity structure of the sub-pixels of each color, the ideal film thickness of the portion corresponding to the upper part of the light emitting center (upper layer) and the part corresponding to the lower part of the light emitting center (lower layer) are shown. The ideal film thickness is illustrated. Further, the lower part of FIG. 9 illustrates the film thickness of each layer included in the organic electroluminescent device. In FIG. 9, the total film thickness of the hole transport layer 23 and the hole injection layer 22 in the blue sub-pixels is thicker than the film thickness suitable for coating. Therefore, it can be seen that it is inappropriate from the viewpoint of coating to arrange the light emitting center on the hole transporting layer side in the organic light emitting layer in the blue sub-pixel.

By the way, when determining the order of cavities in a microcavity structure, only the interference effect is considered in the conventional simulation. Therefore, as shown in FIG. 10, it can be seen that the light extraction efficiency is significantly reduced as the order of the cavities increases. Therefore, from the viewpoint of light extraction efficiency, it is preferable that the order of the cavities is primary, and that it is not preferable to set the order to secondary or tertiary. On the other hand, the inventor of the present application has found that not only the interference effect but also metal quenching should be considered in determining the order of cavities in the microcavity structure. Therefore, the inventor of the present application derived the relationship between the light extraction efficiency and the degree of the cavity in the microcavity structure by a simulation considering the interference effect and metal quenching. The result is shown in FIG. From FIG. 11, it can be seen that in the sub-pixel 12R and the sub-pixel 12G, it is preferable that the order of the cavities is secondary rather than primary. Further, it can be seen from FIG. 11 that in the sub-pixel 12B, it is preferable to set the order of the cavities to the third order rather than the first order. In the sub-pixel 12B, the light extraction efficiency when the cavity order is quadratic is smaller than the light extraction efficiency when the cavity order is tertiary, probably because of the effect of metal quenching. This is probably because it extends a longer distance than the sub-pixels 12R and 12G.

In FIGS. 12 (A), 12 (B), and 12 (C), an intensity map (large light extraction efficiency) when the horizontal axis is the thickness of the lower layer and the vertical axis is the thickness of the upper layer. Map) is shown. FIG. 13 shows the ratio of the peak value in each order when the maximum value of the light extraction efficiency shown in FIGS. 12 (A), 12 (B), and 12 (C) is 100%. There is.

In FIGS. 12 (A), 12 (B), and 12 (C), it can be seen that there are two secondary cavities. Further, in FIGS. 12 (A), 12 (B), and 12 (C), it can be seen that there are three tertiary cavities. From FIGS. 12 (A), 12 (B), and 12 (C), the lower layer is thicker and the upper layer is thicker when the lower layer is thinner and the upper layer is thicker. It can be seen that the light extraction efficiency in the secondary cavity is higher than when the film thickness is reduced. Further, from FIGS. 12 (A), 12 (B), and 12 (C), when the film thickness of the lower layer is the second thinnest and the film thickness of the upper layer is also the second thinnest, the third-order cavity is formed. It can be seen that the light extraction efficiency is the highest. Comparing the light extraction efficiency in the secondary cavity with the light extraction efficiency in the tertiary cavity, in the sub-pixel 12R and the sub-pixel 12G, the light extraction efficiency in the secondary cavity is third-order. It can be seen that the efficiency is higher than the light extraction efficiency in the cavity. On the other hand, in the sub-pixel 12B, it can be seen that the light extraction efficiency in the tertiary cavity is higher than the light extraction efficiency in the secondary cavity.

From the above, it is preferable that the microcavity structures Cr and Cg have an optical path length at which a second cavity is generated from the viewpoint of light extraction efficiency. On the other hand, the microcavity structure Cb preferably has an optical path length at which a third cavity is generated from the viewpoint of light extraction efficiency.

FIG. 14 shows an example of the relationship between the position of the light emitting center 12a and the light extraction intensity in the organic electroluminescent device 12-2 according to the present embodiment. FIG. 15 shows an example of the relationship between the degree of the cavity and the light extraction intensity in the organic electroluminescent device according to the comparative example. FIG. 16 shows an example of the relationship between the absorption coefficient k of the hole transport layer 23 and the light extraction intensity. The absorption coefficient k can be derived using, for example, a spectroscopic ellipsometer that can handle thin films of several tens of nm to several hundreds of nm.

FIG. 14 shows an example of the relationship between the positions of the emission center 12a of the sub-pixel 12R and the sub-pixel 12G and the light extraction intensity when the absorption coefficient k of the hole transport layer 23 in contact with the organic light emitting layer 24 is 0.06. It is shown. FIG. 15 shows an example of the relationship between the positions of the emission center 12a of the sub-pixel 12R and the sub-pixel 12G and the light extraction intensity when the absorption coefficient k of the hole transport layer 23 in contact with the organic light emitting layer 24 is zero. ing. In FIGS. 14 and 15, the resonance points of the microcavity structures Cr and Cg are located at the interface of the organic light emitting layer 24 (specifically, the interface between the organic light emitting layer 24 and the hole transport layer 23). .. FIG. 16 illustrates the relationship between the absorption coefficient k of the hole transport layer 23 and the light extraction intensity at the interface between the organic light emitting layer 24 and the hole transport layer 23 in the sub-pixel 12R and the sub-pixel 12G. ..

By the way, the absorption coefficient k of the hole transport layer 23 is not actually zero, and various values can be taken depending on the material. Of the sub-pixel 12R and the sub-pixel 12G, the hole transport layer 23 of at least one of the sub-pixels 12 usually has an absorption coefficient k of 0. 0 1 or more 0. 0 6 is composed of the following materials. Therefore, when the light emitting center 12a is at the interface between the organic light emitting layer 24 and the hole transport layer 23, the absorption coefficient k of the hole transport layer 23 causes a loss in the near-field energy of light emission. As a result, the light extraction efficiency may decrease.

Therefore, in the organic electroluminescent device 12-2 according to the present embodiment, the absorption coefficient k is 0. 0 1 or more 0. 0 6 organic light-emitting layer 24 of the sub-pixel 12 having a hole transporting layer 23 which is composed of the following materials are, for example, as shown in FIG. 14, of the organic light emitting layer 24, the hole transport layer 23 side The light emitting center 12a (first light emitting center) is provided at a position recessed from the interface by a thickness of 0.4 or less, which is larger than 0 when the thickness of the organic light emitting layer 24 is 1. As a result, the light extraction efficiency is improved as compared with the case where the light emitting center 12a is at the interface between the organic light emitting layer 24 and the hole transport layer 23. The absorption coefficient k is 0. 0 1 or more 0. 0 6 organic light-emitting layer 24 of the sub-pixel 12 having a hole transporting layer 23 which is composed of the following materials are, for example, as shown in FIG. 14, of the organic light emitting layer 24, the hole transport layer 23 side The light emitting center 12a (first light emitting center) is provided at a position recessed from the interface by a thickness of 0.1 or more and 0.2 or less when the thickness of the organic light emitting layer 24 is 1. Is more preferable. When this is done, the light extraction efficiency is most improved.

In FIG. 16, as the absorption coefficient k of the hole transport layer 23 is gradually increased from 0, the light extraction intensity at the interface between the organic light emitting layer 24 and the hole transport layer 23 gradually decreases. Is shown (black circle in the figure). This is because the absorption coefficient k of the hole transport layer 23 causes a loss in the near-field energy of light emission. On the other hand, the location where the light extraction intensity is maximized (white circle in the figure) is 0 when the thickness of the organic light emitting layer 24 is 1 from the interface between the organic light emitting layer 24 and the hole transport layer 23. It is in a position retracted by the thickness of 1 or more and 0.2 or less. As described above, it can be seen that the light extraction intensity can be maximized by arranging the light emitting center 12a at a position slightly distant from the interface (that is, the resonance point) between the organic light emitting layer 24 and the hole transport layer 23. ..

[effect]
Next, the effects of the organic electroluminescent panel 10 of the present embodiment and the organic electroluminescent device 1 provided with the panel 10 will be described.

Conventionally, many attempts have been made to improve the light extraction efficiency of organic electroluminescent devices. This is because power consumption can be reduced by increasing the light extraction efficiency. It is conceivable to use the microcavity effect as one of the means for increasing the light extraction efficiency. However, as shown in FIG. 9, in the optical calculation considering only the interference effect, if the cavities of the second order or higher are used, the light extraction efficiency is rather lowered.

On the other hand, in the present embodiment, the microcavity structures of the red pixel 12R and the green pixel 12G each have an optical path length at which a second cavity is generated. On the other hand, the microcavity structure of the blue pixel 12B has an optical path length at which a third cavity is generated. This is because, in the optical calculation considering not only the interference effect but also the metal quenching effect, as shown in FIG. 10, the light extraction efficiency depends not only on the interference effect but also on the metal quenching effect. According to FIG. 10, in the red pixel 12R and the green pixel 12G, the light extraction efficiency is maximized when the secondary cavity is used, and in the blue pixel 12B, the light extraction efficiency is maximum when the tertiary cavity is used. It becomes. Therefore, the microcavity structure of the red pixel 12R and the green pixel 12G is configured so as to have the optical path length (resonator length) at which the second cavity is generated, and the optical path length (resonator length) at which the third cavity is generated. By configuring the microcavity structure of the blue pixel 12B, not only the interference effect but also the influence of metal quenching can be alleviated, and the light extraction efficiency can be improved. As a result, the element performance of the organic electroluminescent element 12-2 can be improved.

Further, in the present embodiment, in the sub-pixel 12R and the sub-pixel 12G, the distances Lr and Lg between the anode 21 and the cathode 27 are the optical path lengths at which the second cavity is generated. That is, the hole injection layer 22, the hole transport layer 23, the organic light emitting layer 24, the electron transport layer 25, and the electron injection layer 26 are the distance Lr between the anode 21 and the cathode 27 in the sub-pixel 12R and the sub-pixel 12G. , Lg is the film thickness adjusted so as to be the optical path length at which the second cavity is generated. Further, in the sub-pixel 12B, the distance Lb between the anode 21 and the cathode 27 is the optical path length at which the third cavity is generated. That is, the hole injection layer 22, the hole transport layer 23, the organic light emitting layer 24, the electron transport layer 25, and the electron injection layer 26 have a third cavity in the distance Lb between the anode 21 and the cathode 27 in the sub-pixel 12B. The film thickness is adjusted so that the optical path length is such that Thereby, the light extraction efficiency can be improved. As a result, the element performance of the organic electroluminescent element 12-2 can be improved. Further, at this time, the film thickness of the electron transport layer 25 can be made common in the sub-pixel 12R, the sub-pixel 12G, and the sub-pixel 12B. As a result, in the sub-pixel 12R, the sub-pixel 12G, and the sub-pixel 12B, the electron transport layer 25 can be formed of a layer common to each other.

Further, in the present embodiment, the electron transport layer 25 can be formed of a layer common to each other in the sub-pixel 12R, the sub-pixel 12G, and the sub-pixel 12B. As a result, the electron transport layer 24 can be formed by batch film formation without using a mask. As a result, the electron transport layer 24 can be a common vapor deposition film or sputter film in the sub-pixel 12R, sub-pixel 12G, and sub-pixel 12B.

Further, in the present embodiment, the light emitting center 24a is arranged on the hole transport layer 23 side in the organic light emitting layer 24 in the sub pixel 12R and the sub pixel 12G, and the light emitting center 24a is the organic light emitting layer 24 in the sub pixel 12B. It is arranged on the electron transport layer 25 side of the inside. Thereby, for example, as shown in FIG. 8, the film thickness of the organic light emitting layer 24 can be set to a film thickness (45 nm to 80 nm) suitable for coating in each sub-pixel 12, and further, the hole transport layer can be set. The total film thickness of 23 and the hole injection layer 22 can also be a film thickness suitable for coating (50 nm to 130 nm). As a result, the organic electroluminescent element 12-2 in each sub-pixel 12 can be made into a coating type element, so that the organic electroluminescent panel 10 can be enlarged at low cost.

By the way, it is desired to maximize the light extraction with a coating type device which is low cost and easy to manufacture a large panel. The coating type device refers to, for example, an organic light emitting element 12-2 in which a hole transport layer 23 and an organic light emitting layer 24 are formed by coating, and an electron transport layer 25 is collectively formed with respect to RGB pixels. Since the coating type device does not require mask pattern technology, it is possible to manufacture a large and inexpensive panel.

However, in the coating type device, the electron transport layer 25 is collectively formed. Therefore, the film thickness of the electron transport layer 25 is designed to be optimized for the blue pixel 12B, which has the lowest luminous efficiency and the maximum rate-determining power. However, in such a case, there is a problem that the light extraction in the red pixel 12R and the green pixel 12G is lowered.

On the other hand, in the present embodiment, the absorption coefficient k is 0. 0 1 or more 0. From the interface, which is the part where the effect of quenching by the hole transport layer 23 made of a material of 06 or less is the largest, the thickness of the organic light emitting layer 24 is larger than 0 and 0.4 or less when the thickness is 1. The position retracted by the amount of is the light emitting center 12a. As a result, it is possible to suppress the decrease in strength due to the deviation from the resonance point while avoiding the influence of quenching by the hole transport layer 23. As a result, the element performance (light extraction efficiency) of the organic electroluminescent element can be improved.

Further, in the present embodiment, the absorption coefficient k is 0. 0 1 or more 0. 0 6 from the interface is the largest part of the following materials quenching by the hole transport layer 23 made of the effect, 0.1 to 0.2 of the thickness when the thickness of the organic luminescent layer 24 and 1 The position retracted by that amount is the light emitting center 12a. As a result, the decrease in strength due to the deviation from the resonance point can be further suppressed while avoiding the influence of quenching by the hole transport layer 23. As a result, the element performance (light extraction efficiency) of the organic electroluminescent element can be further improved.

<2. Application example>
[Application example 1]
Hereinafter, an application example of the organic electroluminescent device 1 described in the above embodiment will be described. The organic electric field light emitting device 1 is a video signal input from the outside or a video generated internally, such as a television device, a digital camera, a notebook personal computer, a sheet-shaped personal computer, a mobile terminal device such as a mobile phone, or a video camera. It is possible to apply the signal to a display device of an electronic device in all fields for displaying an image or a moving image.

FIG. 17 is a perspective view of the appearance of the electronic device 2 according to the present application example. The electronic device 3 is, for example, a sheet-shaped personal computer having a display surface 320 on the main surface of the housing 310. The electronic device 2 includes an organic electroluminescent device 1 on the display surface 320 of the electronic device 2. The organic electroluminescent device 1 is arranged so that the organic electroluminescent panel 10 faces outward. In this application example, since the organic electroluminescent device 1 is provided on the display surface 320, it is possible to realize an electronic device 2 having high luminous efficiency.

[Application example 2]
An application example of the organic electroluminescent device 12-2 described in the above embodiment will be described below. The organic electroluminescent element 12-2 can be applied to a light source of a lighting device in all fields such as a tabletop or floor-standing lighting device or an indoor lighting device.

FIG. 18 shows the appearance of an indoor lighting device to which the organic electroluminescent element 12-2 is applied. This illuminating device has, for example, an illuminating unit 410 configured to include one or more organic electroluminescent elements 12-2. The lighting units 410 are arranged on the ceiling 420 of the building in an appropriate number and at intervals. The lighting unit 410 can be installed not only in the ceiling 420 but also in an arbitrary place such as a wall 430 or a floor (not shown) depending on the application.

In these illuminating devices, illumination is performed by light from the organic electroluminescent element 12-2. As a result, it is possible to realize a lighting device having high luminous efficiency.

Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the embodiments and can be modified in various ways. For example, in the above embodiment, a plurality of line banks 13 and a plurality of banks 15 are provided on the substrate 14, but instead of these, one pixel bank is provided for each sub-pixel 12. Good.

Further, for example, in the above embodiment, the microcavity structures of the red pixel 12R and the green pixel 12G each have an optical path length in which a second cavity is generated. Further, the microcavity structure of the blue pixel 12B had an optical path length at which the third cavity was generated. However, in the above embodiment, the microcavity structures of the red pixel 12R, the green pixel 12G, and the blue pixel 12B may be different combinations from the above. For example, in the above embodiment, the microcavity structures of the red pixel 12R, the green pixel 12G, and the blue pixel 12B may each have an optical path length at which the first cavity or the second cavity is generated.

The effects described in this specification are merely examples. The effects of the present disclosure are not limited to the effects described herein. The present disclosure may have effects other than those described herein.

Further, for example, the present disclosure may have the following structure.
(1)
An organic electroluminescent device including an anode, an organic layer including a light emitting layer, and a cathode in this order.
In the organic layer, the first organic layer between the light emitting layer and the anode includes a hole transport layer made of a material having an absorption coefficient of 0.01 or more and 0.06 or less.
The light emitting layer has a light emitting center at a position recessed from the interface on the anode side of the light emitting layer by a thickness greater than 0 and less than 0.35 when the thickness of the light emitting layer is 1. And
The organic electroluminescent device is an organic electroluminescent device having a microcavity structure in which the position of the interface is a resonance point.
(2)
The light emitting layer is recessed from the interface on the anode side of the light emitting layer by the thickness of 0.1 or more and 0.2 or less when the thickness of the light emitting layer is 1. The organic electroluminescent device according to (1), which has a center.
(3)
The first distance between the interface and the anode and the second distance between the interface and the cathode are optical path lengths such that the light emitted from the emission center resonates due to the microcavity structure. The organic electroluminescent element according to (1) or (2).
(4)
In the organic layer, the second organic layer between the light emitting layer and the cathode is a thin-film deposition film or a sputtering film.
The organic electroluminescent device according to any one of (1) to (3), wherein the light emitting layer and the first organic layer are coating films.
(5)
The organic electroluminescent device according to any one of (1) to (4), wherein the hole transport layer is an insolubilized hole transport layer.
(6)
Equipped with red pixels, green pixels and blue pixels,
The red pixel, the green pixel, and the blue pixel each have an organic electroluminescent element including an anode, an organic layer including a light emitting layer, and a cathode in this order.
In the organic layer of at least one of the red pixel and the green pixel, the first organic layer between the light emitting layer and the anode is a material having an absorption coefficient of 0.01 or more and 0.06 or less. Contains a hole transport layer composed of
The light emitting layer in the pixel having the hole transport layer has a thickness greater than 0 and less than 0.35 when the thickness of the light emitting layer is 1 from the interface of the light emitting layer on the hole transport layer side. It has a first light emitting center at a position retracted by that amount,
The organic electroluminescent element in a pixel having a hole transport layer is an organic electroluminescent panel having a microcavity structure in which the position of the interface is a resonance point.
(7)
In the organic layer, the second organic layer between the light emitting layer and the cathode includes an electron transporting layer.
The electron transport layer is a vapor deposition film or a sputtering film, and is
The organic electroluminescent panel according to (6), wherein the light emitting layer and the first organic layer are coating films.
(8)
The organic electroluminescent panel according to (7), wherein in the red pixel, the green pixel, and the blue pixel, the electron transport layer is formed of a layer common to each other.
(9)
The organic electroluminescent panel according to (7) or (8), wherein in the blue pixel, the light emitting layer has a second light emitting center at a position on the electron transporting layer side of the light emitting layer.
(10)
Organic electroluminescent panel and
A drive circuit for driving the organic electroluminescent panel is provided.
The organic electroluminescent panel has red pixels, green pixels and blue pixels.
The red pixel, the green pixel, and the blue pixel each have an organic electroluminescent element including an anode, an organic layer including a light emitting layer, and a cathode in this order.
In the organic layer of at least one of the red pixel, the green pixel, and the blue pixel, the first organic layer between the light emitting layer and the anode has an absorption coefficient of 0.01 or more and 0. Contains a hole transport layer composed of 06 or less material
The light emitting layer in the pixel having the hole transport layer has a thickness greater than 0 and less than 0.35 when the thickness of the light emitting layer is 1 from the interface of the light emitting layer on the hole transport layer side. It has a light emitting center at a position retracted by that amount,
The organic electroluminescent device in a pixel having a hole transport layer is an organic electroluminescent device having a microcavity structure in which the position of the interface is a resonance point.
(11)
Equipped with an organic electroluminescent device
The organic electroluminescent device is
Organic electroluminescent panel and
It has a drive circuit that drives the organic electroluminescent panel.
The organic electroluminescent panel has red pixels, green pixels and blue pixels.
The red pixel, the green pixel, and the blue pixel each have an organic electroluminescent element including an anode, an organic layer including a light emitting layer, and a cathode in this order.
In the organic layer of at least one of the red pixel, the green pixel, and the blue pixel, the first organic layer between the light emitting layer and the anode has an absorption coefficient of 0.01 or more and 0. Contains a hole transport layer composed of 06 or less material
The light emitting layer in the pixel having the hole transport layer has a thickness greater than 0 and less than 0.35 when the thickness of the light emitting layer is 1 from the interface of the light emitting layer on the hole transport layer side. It has a light emitting center at a position retracted by that amount,
The organic electroluminescent device in a pixel having a hole transport layer is an electronic device having a microcavity structure in which the position of the interface is a resonance point.

1 ... organic electroluminescent device, 10 ... organic electroluminescent panel, 11 ... pixel, 12, 12R, 12G, 12B ... sub-pixel, 12-1 ... pixel circuit, 12-2, 12r, 12g, 12b ... organic electroluminescent element , 13 ... line bank, 14 ... substrate, 15 ... bank, 16 ... groove, 20 ... controller, 21 ... anode, 22 ... hole injection layer, 23 ... hole transport layer, 24, 24a ... light emitting region, 25 ... electrons Transport layer, 26 ... electron injection layer, 27 ... cathode, 28 ... sealing layer, 30 ... driver, 31 ... horizontal selector, 32 ... light scanner, Tr1 ... drive transistor, Tr2 ... selective transistor, Cs ... holding capacity, DSL ... Power line, DTL ... signal line, Vgs ... gate-source voltage, Vsig ... signal voltage, WSL ... selection line.

Claims (11)

An organic electroluminescent device including an anode, an organic layer including a light emitting layer, and a cathode in this order.
In the organic layer, the first organic layer between the light emitting layer and the anode includes a hole transport layer made of a material having an absorption coefficient of 0.01 or more and 0.06 or less.
The light emitting layer has a light emitting center at a position recessed from the interface on the anode side of the light emitting layer by a thickness greater than 0 and 0.4 or less when the thickness of the light emitting layer is 1. And
The organic electroluminescent device is an organic electroluminescent device having a microcavity structure in which the position of the interface is a resonance point. The light emitting layer is recessed from the interface on the anode side of the light emitting layer by the thickness of 0.1 or more and 0.2 or less when the thickness of the light emitting layer is 1. The organic electroluminescent device according to claim 1, which has a center. The first distance between the interface and the anode and the second distance between the interface and the cathode are optical path lengths such that the light emitted from the emission center resonates due to the microcavity structure. The organic electroluminescent element according to claim 1 or 2. In the organic layer, the second organic layer between the light emitting layer and the cathode is a thin-film deposition film or a sputtering film.
The organic electroluminescent device according to any one of claims 1 to 3, wherein the light emitting layer and the first organic layer are coating films. The organic electroluminescent device according to any one of claims 1 to 4, wherein the hole transport layer is an insolubilized hole transport layer. Equipped with red pixels, green pixels and blue pixels,
The red pixel, the green pixel, and the blue pixel each have an organic electroluminescent element including an anode, an organic layer including a light emitting layer, and a cathode in this order.
In the organic layer of at least one of the red pixel and the green pixel, the first organic layer between the light emitting layer and the anode is a material having an absorption coefficient of 0.01 or more and 0.06 or less. Contains a hole transport layer composed of
The light emitting layer in the pixel having the hole transport layer has a thickness of 0.4 or less, which is larger than 0 when the thickness of the light emitting layer is 1 from the interface of the light emitting layer on the hole transport layer side. It has a first light emitting center at a position retracted by that amount,
The organic electroluminescent element in a pixel having a hole transport layer is an organic electroluminescent panel having a microcavity structure in which the position of the interface is a resonance point. In the organic layer, the second organic layer between the light emitting layer and the cathode includes an electron transporting layer.
The electron transport layer is a vapor deposition film or a sputtering film, and is
The organic electroluminescent panel according to claim 6, wherein the light emitting layer and the first organic layer are coating films. The organic electroluminescent panel according to claim 7, wherein in the red pixel, the green pixel, and the blue pixel, the electron transport layer is formed of a layer common to each other. The organic electroluminescent panel according to claim 7 or 8, wherein in the blue pixel, the light emitting layer has a second light emitting center at a position on the electron transporting layer side of the light emitting layer. Organic electroluminescent panel and
A drive circuit for driving the organic electroluminescent panel is provided.
The organic electroluminescent panel has red pixels, green pixels and blue pixels.
The red pixel, the green pixel, and the blue pixel each have an organic electroluminescent element including an anode, an organic layer including a light emitting layer, and a cathode in this order.
In the organic layer of at least one of the red pixel, the green pixel, and the blue pixel, the first organic layer between the light emitting layer and the anode has an absorption coefficient of 0.01 or more and 0. Contains a hole transport layer composed of 06 or less material
The light emitting layer in the pixel having the hole transport layer has a thickness of 0.4 or less, which is larger than 0 when the thickness of the light emitting layer is 1 from the interface of the light emitting layer on the hole transport layer side. It has a light emitting center at a position retracted by that amount,
The organic electroluminescent device in a pixel having a hole transport layer is an organic electroluminescent device having a microcavity structure in which the position of the interface is a resonance point. Equipped with an organic electroluminescent device
The organic electroluminescent device is
Organic electroluminescent panel and
It has a drive circuit that drives the organic electroluminescent panel.
The organic electroluminescent panel has red pixels, green pixels and blue pixels.
The red pixel, the green pixel, and the blue pixel each have an organic electroluminescent element including an anode, an organic layer including a light emitting layer, and a cathode in this order.
In the organic layer of at least one of the red pixel, the green pixel, and the blue pixel, the first organic layer between the light emitting layer and the anode has an absorption coefficient of 0.01 or more and 0. Contains a hole transport layer composed of 06 or less material
The light emitting layer in the pixel having the hole transport layer has a thickness of 0.4 or less, which is larger than 0 when the thickness of the light emitting layer is 1 from the interface of the light emitting layer on the hole transport layer side. It has a light emitting center at a position retracted by that amount,
The organic electroluminescent device in a pixel having a hole transport layer is an electronic device having a microcavity structure in which the position of the interface is a resonance point.

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