JP6915880B2 - Organic electroluminescent devices, organic electroluminescent devices and electronic devices - Google Patents

Description

The present disclosure relates to organic electroluminescent devices, 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 Patent Application Laid-Open No. 2007-533157

By the way, in an organic electroluminescent device, it is required to improve the device characteristics without impairing the energization stability of the organic electroluminescent element. Therefore, it is desirable to provide an organic electroluminescent element, an organic electroluminescent device, and an electronic device capable of improving device characteristics without impairing energization stability.

The organic electroluminescent device according to the embodiment of the present disclosure includes a first reflective layer, a second reflective layer, and a monochromatic organic light emitting layer provided between the first reflective layer and the second reflective layer. It has. The organic electroluminescent device further includes an Ag electrode layer provided between the organic light emitting layer and the second reflection layer, and a Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer. The Ag electrode layer is thinner than the second reflective layer and has a thickness of 0.1 nm or more and 10 nm or less. The second reflective layer has a thickness of 5 nm or more and 30 nm or less.

The organic electroluminescent device according to the embodiment of the present disclosure includes a plurality of organic electroluminescent devices. In the organic electroluminescent device, at least one of the plurality of organic electroluminescent device has the same components as chromatic electromechanical field emission device described above.

The electronic device according to the embodiment of the present disclosure includes an organic electroluminescent device. The organic electroluminescent device in an electronic device includes a perforated electromechanical field emission device and the same components described above.

Yes electromechanical field emitting elements Ru engaged to an embodiment of the present disclosure, according to chromatic electromechanical field light-emitting element in the organic light emitting device and an electronic device provided as well, between the first reflective layer and the second reflective layer Since the laminated body in which the Yb electron injection layer and the Ag electrode layer in contact with each other are laminated in this order from the organic light emitting layer side is provided, the device characteristics can be improved without impairing the energization stability. The above content is an example of the present disclosure. The effects of the present disclosure are not limited to those described above, and may be other different effects, or may further include other effects.

It is a figure which shows an example of the cross-sectional structure of the organic electroluminescent element which concerns on 1st Embodiment of this disclosure. It is a figure which shows an example of the path of electric current and light. It is a figure which shows an example of the relationship between Ag film thickness and sheet resistance. It is a figure which shows an example of the cross-sectional structure of the organic electroluminescent element which concerns on a comparative example. It is a figure which shows an example of the cross-sectional structure of the organic electroluminescent element which concerns on the modification. It is a figure which shows an example of the relationship between Ag film thickness, sheet resistance, Yb electron injection layer, and Yb protection layer. It is a figure which shows an example of the cross-sectional structure of the organic electroluminescent element which concerns on the modification. It is a figure which shows an example of the cross-sectional structure of the organic electroluminescent element which concerns on the modification. It is a figure which shows an example of the cross-sectional structure of the organic electroluminescent element which concerns on the modification. It is a figure which shows an example of the cross-sectional structure of the organic electroluminescent element which concerns on the modification. It is a figure which shows an example of the schematic structure of the organic electroluminescent device which concerns on 2nd Embodiment of this disclosure. It is a figure which shows an example of the circuit structure of the pixel of FIG. It is a top view which shows an example of the schematic structure of the display panel of FIG. 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. The explanation will be given in the following order.

1. 1. First Embodiment (organic electroluminescent device)
2. Modification example of the first embodiment (organic electroluminescent device)
3. 3. Second Embodiment (organic electroluminescent device)
4. Application example (electronic equipment, lighting equipment)

<1. First Embodiment>
[Constitution]
FIG. 1 shows an example of the 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 on, for example, the substrate 10. The organic electroluminescent element 1 includes, for example, a reflective layer 11 (anode, first reflective layer), a hole injection layer 12, a hole transport layer 13, an organic light emitting layer 14, an electron transport layer 15, and an electron injection layer 16 (Yb electrons). The element structure includes an injection layer), a cathode 17 (Ag electrode layer), a film thickness adjusting layer 18, and a reflection layer 19 (second reflection layer) in this order from the substrate 10 side. The hole injection layer 12 and the hole transport layer 13 are provided on the hole injection side of the organic light emitting layer 14. The electron transport layer 15 and the electron injection layer 16 are provided on the electron injection side of the organic light emitting layer 14. The organic light emitting layer 14 is a monochromatic light emitting organic light emitting layer provided between the reflective layer 11 and the reflective layer 19. The cathode 17 is an electrode layer provided between the organic light emitting layer 14 and the reflective layer 19. The electron injection layer 16 is in contact with the organic light emitting layer 14 side of the cathode 17. The film thickness adjusting layer 18 is provided between the cathode 17 and the reflective layer 19.

In this embodiment, the organic electroluminescent device 1 is provided with a microcavity structure. The microcavity structure has an effect of enhancing light of a specific wavelength by utilizing, for example, the resonance of light generated between the reflection layer 11 and the reflection layer 19. The light emitted from the organic light emitting layer 14 is multiplely reflected between the reflective layer 11 and the reflective layer 19. At this time, a specific wavelength component of the light emitted from the organic light emitting layer 14 is strengthened. The optical path length between the reflective layer 11 and the reflective layer 19 corresponds to the emission spectrum peak wavelength of the light emitted from the organic light emitting layer 14. Due to the microcavity structure, the light emitted from the organic light emitting layer 14 is repeatedly reflected between the reflective layer 11 and the reflective layer 19 within a predetermined optical length range, as shown in FIG. 2, for example, and the optical path is repeated. The light L having a specific wavelength corresponding to the length is resonated and enhanced, while the light having a wavelength not corresponding to the optical path length is weakened. As a result, the spectrum of light L taken out to the outside becomes steep and high in intensity, and the brightness and color purity are improved. Therefore, the distance between the reflective layer 11 and the reflective layer 19 is the optical path length at which the cavity is generated. 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 substrate 10 is, for example, a transparent substrate having light transmittance such as a transparent substrate, and is, for example, a glass substrate. Examples of the material of the glass substrate used for the substrate 10 include non-alkali glass, soda glass, non-fluorescent glass, phosphoric acid-based glass, boric acid-based glass, and quartz. The substrate 10 is not limited to a glass substrate, and may be a translucent resin substrate or a TFT (thin film transistor) substrate which is a backplane of an organic EL display device. Examples of the material of the translucent resin substrate used for the substrate 10 include acrylic resin, styrene resin, polycarbonate resin, epoxy resin, polyethylene, polyester, and silicone resin. The substrate 10 may be a substrate having high flexibility, or may be a highly rigid substrate having almost no flexibility.

The reflective layer 11 is formed on, for example, the substrate 10. The reflective layer 11 is a reflective electrode (reflective metal layer) having reflectivity. Examples of the material of the reflective electrode include aluminum (Al), silver (Ag), and an alloy of aluminum or silver. The reflective layer 11 is used as an anode. The reflective layer 11 may be an Ag electrode layer made of Ag or an Ag alloy having a high reflectance.

The hole injection layer 12 has a function of injecting holes injected from the reflection layer 11 (anode) into the hole transport layer 13 and the organic light emitting layer 14. The hole injection layer 12 is made of, for example, an inorganic material having a hole injection property. Examples of the inorganic material having a hole injecting property include oxidation of silver (Ag), molybdenum (Mo), chromium (Cr), vanadium (V), tungsten (W), nickel (Ni), iridium (Ir) and the like. Things (inorganic oxides) and the like can be mentioned. The hole injection layer 12 is composed of, for example, a vapor-deposited film or a sputtered film of an inorganic oxide. The hole injection layer 12 may be made of an organic material having a hole injection property. Examples of the organic material having a hole injecting property include a conductive polymer material such as PEDOT (a mixture of polythiophene and polystyrene sulfonic acid). The hole injection layer 12 is composed of, for example, a coating film made of an organic material. The hole injection layer 12 may be made of a vapor-deposited film made of an organic material.

The hole transport layer 13 has a function of transporting the holes injected from the reflection layer 11 to the organic light emitting layer 14. The hole transport layer 13 is composed of, for example, a material (hole transportable material) having a function of transporting holes injected from the reflection layer 11 to the organic light emitting layer 14. Examples of the hole transporting material include arylamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, amino-substituted chalcone derivatives, and 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 organic light emitting layer 14 has a function of emitting light of a predetermined color (monochromatic light) by recombination of holes and electrons. The organic light emitting layer 14 is composed of an organic light emitting material that emits light by generating excitons by recombination of holes and electrons. The organic light emitting layer 14 is, for example, a coating film, and is formed, for example, by applying and drying a solution containing the above organic light emitting material as a main component of the solute. The organic light emitting layer 14 may be made of a vapor-deposited film.

The organic light emitting layer 14 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 14 is composed of a plurality of laminated organic light emitting layers, the organic light emitting layer 14 is, for example, laminated with a plurality of organic light emitting layers in which the main components of the above organic light emitting materials are common to each other. It is a thing.

The organic light emitting material which is a raw material (material) of the organic 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 which is a raw material (material) of the organic light emitting layer 14 may be a dopant material alone. The host material mainly has a function of transporting charges of 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 organic light emitting layer 14, 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, and perylene derivatives. 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, indol 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 14, 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 fluorescent dopant material of the organic light emitting layer 14, 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), rhenium (Re), or ruthenium (Ru) and a ligand. Can be mentioned.

The electron transport layer 15 has a function of transporting electrons injected from the cathode 17 to the organic light emitting layer 14. The electron transport layer 15 is configured to include, for example, a material (electron transportable material) having a function of transporting electrons injected from the cathode 17 to the organic light emitting layer 14. The electron transport layer 15 is composed of, for example, a thin-film deposition film or a sputter film. The electron-transporting material 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 benzimidazoline ring, a phenanthroline ring, a quinazoline ring, and the like in the skeleton. The electron-transporting material may be doped with a metal having electron-transporting property. In this case, the electron transport layer 15 is an organic electron transport layer containing a dope 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 dope metal contained in the electron transport layer 15 include a transition metal such as ytterbium (Yb).

The electron injection layer 16 has a function of injecting electrons injected from the cathode 17 into the electron transport layer 15 and the organic light emitting layer 14. The electron injection layer 16 is composed of, for example, a material (electron injectable material) having a function of promoting the injection of electrons from the cathode 17 into the electron transport layer 15 and the organic light emitting layer 14. Examples of the electron-injectable material include ytterbium (Yb). The electron injection layer 16 may be, for example, a Yb layer composed of Yb. The dope metal contained in the electron transport layer 15 may be the same metal as the electron injectable material described above. The film thickness of the electron injection layer 16 is, for example, 0.1 nm or more and 5 nm or less. If the thickness of the electron injection layer 16 is too thin, the function of promoting electron injection is deteriorated, and if the thickness is too thick, the light emitting characteristics may be deteriorated due to a decrease in transmittance. Further, the Yb layer has a function of improving the film quality of the cathode 17 (Ag) formed in contact with the cathode 17 side and lowering the sheet resistance. As a result, the device characteristics can be improved without impairing the energization stability even in the cathode 17 (Ag) having a thin film thickness.

The cathode 17 is a transparent electrode (translucent metal layer) having translucency. As the material of the transparent electrode, for example, aluminum (Al), magnesium (Mg), silver (Ag), aluminum-lithium alloy, magnesium-silver alloy and the like are used. The cathode 17 that functions as a transparent electrode is, for example, an Al layer, an Mg layer, an Ag layer, an AlLi alloy layer, or an MgAg alloy layer having a thickness of 0.1 nm or more and 10 nm or less. In the present embodiment, when the substrate 10 and the reflective layer 11 are reflective and the cathode 17 and the reflective layer 19 are translucent, the organic electroluminescent element 1 is viewed from the reflective layer 19 side. It has a top emission structure that emits light.

When the film thickness of the cathode 17 is increased, the cavity effect due to the reflection of the cathode 17 becomes stronger, the front luminance becomes high, and the viewing angle characteristic deteriorates. When the film thickness of the cathode 17 is reduced, the cavity effect due to the cathode 17 is reduced, the front luminance is suppressed, and the viewing angle characteristic is improved. Since the cavity effect is also generated in the reflective layer 19, the cavity effect is complicated by increasing the film thickness of the cathode 17 and increasing the reflectivity. The change in light emission characteristics due to the difference in the finished film thickness with respect to the design of the film configuration also becomes large. In addition, the risk of uneven light emission increases as the change in light emission characteristics increases.

Therefore, in the present embodiment, for example, the film thickness of the cathode 17 is thinner than that of the reflective layer 19. For example, the film thickness of the reflective layer 19 is preferably 5 nm or more and 30 nm or less, and the film thickness of the cathode 17 is thinner than the film thickness of the reflective layer 19 and is 0.1 nm or more and 10 nm or less. It is desirable to be there. Further, it is more desirable that the film thickness of the cathode 17 is thinner than the film thickness of the reflective layer 19 and is 0.1 nm or more and 5 nm or less. By doing so, the reflection by the cathode 17 is suppressed, the cathode 17 hardly functions as the reflection layer of the cavity, and the deterioration of the viewing angle characteristic and the deterioration of the device characteristic due to the film thickness deviation can be suppressed.

On the other hand, if the cathode 17 is made thin, the sheet resistance deteriorates. That is, a structure that makes the cathode 17 as thin as possible and suppresses the increase in sheet resistance is required. Therefore, in the present embodiment, the cathode 17 is, for example, an Ag layer, and the electron injection layer 16 is, for example, a Yb layer. By forming the cathode 17 on the electron injection layer 16 made of Yb, the sheet resistance can be lowered, and even if the cathode 17 is thin, the device characteristics can be improved without impairing the conduction stability. Can be done.

The film thickness adjusting layer 18 is, for example, a layer for adjusting the distance between the reflective layer 11 and the reflective layer 19 so as to have a predetermined optical path length. The film thickness adjusting layer 18 is made of, for example, a transparent conductive material such as ITO or IZO. The film thickness adjusting layer 18 is, for example, an ITO layer or an IZO layer. The film thickness of the ITO layer or the IZO layer used for the film thickness adjusting layer 18 is, for example, a value larger than 40 nm. The film thickness adjusting layer 18 has a higher resistance than the cathode 17, and does not form a current path. The film thickness adjusting layer 18 may be a metal-non-doped organic layer or a metal-doped organic layer. As long as the film thickness adjusting layer 18 does not form a current path in the organic electroluminescent element 1, the film thickness adjusting layer 18 may have various configurations.

The reflective layer 19 is a transparent electrode (translucent metal layer) having translucency. As the material of the transparent electrode, for example, aluminum (Al), magnesium (Mg), silver (Ag), aluminum-lithium alloy, magnesium-silver alloy and the like are used. The reflective layer 19 that functions as a transparent electrode is, for example, an Al layer, an Mg layer, an Ag layer, an AlLi alloy layer, or an MgAg alloy layer having a thickness of 5 nm or more and 30 nm or less.

When the organic electroluminescent element 1 is formed as pixels of a display panel, the organic electroluminescent element 1 is provided with a plurality of banks 25 for partitioning each pixel of the display panel on the substrate 10. The bank 25 is made 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 bank 25 is preferably formed of, for example, an insulating resin having heat resistance and resistance to a solvent. The bank 25 is formed, for example, by processing an insulating resin into a desired pattern by photolithography and development. The cross-sectional shape of the bank 25 may be, for example, a forward taper type as shown in FIG. 1 or a reverse taper type having a narrow hem.

The organic electroluminescent element 1 includes a wiring 21 that is electrically conductive with the reflective layer 11 (anode) and the cathode 17. The wiring 21 is a wiring for supplying a current between the reflective layer 11 (anode) and the cathode 17. In FIG. 1, of the cathode 17, the electron injection layer 16 and the electron transport layer 15, a portion extending beyond the bank 25 (a portion surrounded by a broken line in FIG. 1; hereinafter, “wiring layer 21A”” is shown. The electrode layer 21B formed in the peripheral region 20B surrounding the pixel region 20A constitutes a part of the wiring 21 for supplying a current between the reflection layer 11 (anode) and the cathode 17. The situation is illustrated. The wiring layer 21A and the electrode layer 21B are provided in a region (peripheral region 20B) around the pixel region 20A. The electrode layer 21B is provided in the same layer as the reflective layer 11, for example, and is formed of, for example, a material common to the reflective layer 11. The pixel region 20A includes a region of the organic electroluminescent element 1 facing a region (light emitting region 14A) that emits light due to current injection by the reflection layer 11 and the cathode 17. The light emitting region 14A is generated in the organic light emitting layer 14 by the current injection by the reflective layer 11 and the cathode 17. When the reflective layer 11 is surrounded by the bank 25, the light emitting region 14A is generally an opening formed by the bank 25 in the organic light emitting layer 14, and the reflective layer 11 and the hole injection layer are formed. It occurs in a region facing a portion where 12 is in direct contact with each other.

FIG. 3 shows an example of the relationship between the Ag film thickness and the sheet resistance. In the present embodiment, the cathode 17 is, for example, an Ag layer, and the electron injection layer 16 is, for example, a Yb layer. At this time, by setting the thickness of the cathode 17 (Ag layer) to 20 nm or less and the thickness of the electron injection layer 16 (Yb layer) to 0.1 nm or more and 5 nm or less, as shown in FIG. The sheet resistance value of the electron injection layer 16 (Yb layer) / cathode 17 (Ag layer) is smaller than the sheet resistance value of the Ag single layer. When the thickness of the cathode 17 (Ag layer) is about 5 nm, the sheet resistance value of the electron injection layer 16 (Yb layer) / cathode 17 (Ag layer) is 20 ohms as shown in FIG. It is about / sq to 30 ohms / sq. Therefore, a low resistance cathode 17 can be realized by setting the thickness of the cathode 17 (Ag layer) to 5 nm or more and 20 nm or less and the thickness of the electron injection layer 16 (Yb layer) to 0.1 nm or more and 5 nm or less. Can be done. As a result, the device characteristics can be improved without impairing the energization stability even in the cathode 17 (Ag) having a thin film thickness.

Next, the effect of the organic electroluminescent device 1 according to the present embodiment will be described with reference to comparative examples. FIG. 4 shows an example of the cross-sectional configuration of the organic electroluminescent device 100 according to the comparative example. The organic electroluminescent device 100 corresponds to the organic electroluminescent device 1 according to the present embodiment in which the cathode 17 is omitted and the film thickness adjusting layer 18 is composed of a metal-doped organic layer. In the comparative example, the function of the cathode 17 is carried out by the reflective layer 19. In the comparative example, since the reflective layer 19 is responsible for the function of the cathode 17, the electron injection layer 16 is formed between the film thickness adjusting layer 18 and the reflective layer 19.

The organic electroluminescent device 100 is provided with a microcavity structure similar to that of the organic electroluminescent device 1 according to the present embodiment. In this structure, the hole h passes from the reflection layer 11 through the hole injection layer 12 and the hole transport layer 13 toward the organic light emitting layer 14. On the other hand, electrons e in the peripheral region 20B, the electron transport layer 15 from the electrode layer 21 B, the thickness adjusting layer 18, the electron injection layer 16, enters the pixel region 20A through the reflective layer 19, an electron injection in the pixel area 20A It passes through the layer 16, the film thickness adjusting layer 18, and the electron transport layer 15 toward the organic light emitting layer 14. Then, in the organic light emitting layer 14, the holes h and the electrons e are recombined, and light emission occurs. When light emission occurs, the doped metal deteriorates over time in the film thickness adjusting layer 18 composed of the metal-doped organic layer, and the film thickness adjusting layer 18 becomes highly resistant. As a result, the voltage applied to the organic electroluminescent element 100 becomes high. Further, the dope metal in the film thickness adjusting layer 18 diffuses to the organic light emitting layer 14, causing quenching and deterioration of light emitting characteristics. As described above, in the organic electroluminescent element 100, the energization stability is impaired and the device characteristics are deteriorated.

On the other hand, in the present embodiment, the electron injection layer 16 (Yb electron injection layer) and the cathode 17 (Ag electrode layer) in contact with each other are placed between the reflection layer 11 (anode) and the reflection layer 19 from the organic light emitting layer 14 side. Laminated bodies laminated in this order are provided. In this structure, the hole h passes from the reflection layer 11 through the hole injection layer 12 and the hole transport layer 13 toward the organic light emitting layer 14. On the other hand, electrons e in the peripheral region 20B, the electron transport layer from the electrode layer 21 B 15, the electron injection layer 16, enters the pixel region 20A through the cathode 17, the electron injection layer 16 in the pixel region 20A, the electron transport layer 15 It goes to the organic light emitting layer 14. Then, in the organic light emitting layer 14, the holes h and the electrons e are recombined, and light emission occurs. That is, in this structure, electricity does not flow through the film thickness adjusting layer 18. That is, the dope metal does not deteriorate over time and the film thickness adjusting layer 18 does not increase in resistance. Thereby, the device characteristics can be improved without impairing the energization stability.

Further, in the present embodiment, the cathode 17 (Ag electrode layer) is thinner than the reflective layer 19. As a result, the cathode 17 having low resistance can be realized, and at the same time, the cathode 17 and the electron injection layer 16 can hardly function as the reflection layer of the cavity. As a result, the device characteristics can be improved without impairing the energization stability.

Further, in the present embodiment, a film thickness adjusting layer 18 having a higher resistance than that of the cathode 17 (Ag electrode layer) is provided between the cathode 17 (Ag electrode layer) and the reflection layer 19. As a result, the film thickness adjusting layer 18 does not form a current path, so even if the film thickness adjusting layer 18 is a metal-doped organic layer, there is no effect thereof. Further, since no current flows through the film thickness adjusting layer 18 in the first place, the metal doped in the film thickness adjusting layer 18 does not diffuse. As a result, the device characteristics can be improved without impairing the energization stability.

<2. Modification example of the first embodiment>
[Modification example A]
In the above embodiment, for example, as shown in FIG. 5, a protective layer 28 (Yb protective layer) in contact with the reflective layer 19 side of the cathode 17 (Ag electrode layer) may be provided. The protective layer 28 is a layer that functions as a low resistance layer for lowering the resistance value when the cathode 17 (Ag electrode layer) is very thin. The protective layer 28 is, for example, a Yb layer having a thickness of 0.1 nm or more and 5 nm or less. The protective layer 28 has a lower resistance than the film thickness adjusting layer 18.

FIG. 6 shows an example of the relationship between the Ag film thickness, the sheet resistance, the Yb electron injection layer, and the Yb protective layer. In FIG. 6, the cathode 17 is, for example, an Ag layer, and the electron injection layer 16 is, for example, a Yb layer. When the film thickness of the Ag layer is 5 nm and the electron injection layer 16 made of Yb is not provided (comparative example), the sheet resistance value is significantly increased to 10 M ohm / sq or more. It ends up. On the other hand, when the electron injection layer 16 made of Yb is provided (Example), a low resistance cathode having a sheet resistance value of about 20 ohms / sq to 30 ohms / sq can be realized. Further, when the film thickness of the Ag layer is 2 nm, the electron injection layer 16 made of Yb is not provided (comparative example), or the electron injection layer 16 made of Yb is provided. If the protective layer 28 made of Yb is not provided (Example), the sheet resistance value is significantly increased to 10 M ohm / sq or more. On the other hand, when the electron injection layer 16 made of Yb is provided and the protective layer 28 made of Yb is provided (modification example A), the sheet resistance value is as low as about 350 to 400 ohms / sq. A good cathode 17 can be realized. As described above, in this modification, the low resistance cathode 17 can be realized by providing the protective layer 28 (Yb protective layer) in contact with the reflective layer 19 side of the cathode 17 (Ag electrode layer). .. As a result, the device characteristics can be improved without impairing the energization stability even in the cathode 17 (Ag electrode layer) having a thin film thickness.

[Modification B]
Further, in the above embodiment and the modified example A, for example, as shown in FIGS. 7 and 8, the reflective layer 19 and the cathode 17 (Ag electrode layer) may be electrically conductive. Further, in the above embodiment, the reflective layer 19 may be in contact with, for example, a part of the cathode 17 (Ag electrode layer). Specifically, in the above embodiment, the reflective layer 19 and the cathode 17 (Ag electrode layer) are not opposed to the light emitting region 14A of the organic light emitting layer 14 in the thickness direction (for example, the bank 25 and the thickness). It may be electrically conductive in the regions facing each other in the direction or the peripheral region 20B). As described above, the reflective layer 19 and the cathode 17 (Ag electrode layer) are electrically conductive, so that the low-resistance reflective layer 19 plays the role of auxiliary wiring. As a result, the influence of the resistance can be reduced, and when the panel is enlarged, the phenomenon (voltage drop) in which the voltage is less likely to be applied to the central portion of the panel can be reduced. Further, in a configuration in which a film thickness adjusting layer 18 having a higher resistance than that of the cathode 17 (Ag electrode layer) is provided between the cathode 17 (Ag electrode layer) and the reflective layer 19, the film thickness adjusting layer 18 is a current. No longer constructs a route. As a result, even if the film thickness adjusting layer 18 is a metal-doped organic layer, there is no effect thereof. Further, since no current flows through the film thickness adjusting layer 18 in the first place, the metal doped in the film thickness adjusting layer 18 does not diffuse. As a result, the device characteristics can be improved without impairing the energization stability.

[Modification C]
Further, in the above-described embodiment, the modified example A and the modified example B, when the decrease in the transmittance due to the increase in the film thickness of the cathode 17 and the change in the light emitting characteristics due to the film thickness deviation can be controlled, the film thickness of the cathode 17 is formed. May be the same as or thicker than the film thickness of the reflective film 19. For example, as shown in FIG. 9, the film thickness of the cathode 17 may be the same as or thicker than the film thickness of the reflective film 19. In this case, the sheet resistance of the cathode 17 can be reduced, and the device characteristics can be improved.

[Modification D]
Further, the above embodiment, in the modified example A and modification B, the thickness of the cathode 17, for example, is relatively thin in the pixel region 20A, the periphery of the pixel region 20 A region (peripheral region 20B) May be relatively thick. For example, as shown in FIG. 10, the thickness of the cathode 17 has become relatively thin in the pixel area 20A, it becomes relatively thick in the area around the pixel region 20 A (peripheral region 20B) May be good. In this case, the voltage drop in the peripheral region 20B can be reduced, and the device characteristics can be improved.

<3. Second Embodiment>
[Constitution]
FIG. 11 shows an example of a schematic configuration of the organic electroluminescent device 2 according to the second embodiment of the present disclosure. FIG. 12 shows an example of the circuit configuration of each pixel 23 provided in the organic electroluminescent device 2. The organic electroluminescent device 2 includes, for example, a display panel 20, a controller 30, and a driver 40. The display panel 20 has a plurality of pixels 23 arranged in a matrix in the pixel area 20A. The driver 40 is mounted on the outer edge portion of the display panel 20 (peripheral area 20B, which is a peripheral area of the pixel area 20A). The controller 30 and the driver 40 drive the display panel 20 based on the video signal Din and the synchronization signal Tin input from the outside.

(Display panel 20)
The display panel 20 displays an image based on the video signal Din and the synchronization signal Tin input from the outside by driving each pixel 23 in an active matrix by the controller 30 and the driver 40. The display panel 20 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 23.

The scanning line WSL is used for selecting each pixel 23, and supplies a selection pulse for selecting each pixel 23 for each predetermined unit (for example, a pixel row) to each pixel 23. The signal line DTL is used to supply the signal voltage Vsig corresponding to the video signal Din to each pixel 23, and supplies a data pulse including the signal voltage Vsig to each pixel 23. The power supply line DSL supplies electric power to each pixel 23.

The plurality of pixels 23 are composed of, for example, a plurality of pixels 23 that emit red light, a plurality of pixels 23 that emit green light, and a plurality of pixels 23 that emit blue light. The plurality of pixels 23 may be further composed of, for example, a plurality of pixels 23 that emit other colors (for example, white, yellow, etc.).

Each signal line DTL is connected to the output end of the horizontal selector 41 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 42 described later. For example, one 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 supply line DSLs are assigned to each pixel row.

Each pixel 23 has, for example, a pixel circuit 23-1 and an organic electroluminescent element 23-2. The organic electroluminescent device 23-2 is, for example, the organic electroluminescent device 1 according to the above embodiment and a modification thereof. At least one of the plurality of pixels 23 included in the display panel 20 has an organic electroluminescent element 1 according to the above embodiment and a modification thereof. That is, at least one of the plurality of organic electroluminescent elements 23-2 included in the display panel 20 is composed of the organic electroluminescent element 1 according to the above embodiment and its modification.

The pixel circuit 23-1 controls the light emission / quenching of the organic electroluminescent element 23-2. The pixel circuit 23-1 has a function of holding the voltage written to each pixel 23 by the writing scan described later. The pixel circuit 23-1 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 23-2. The drive transistor Tr1 drives the organic electroluminescent element 23-2. The drive transistor Tr1 controls the current flowing through the organic electroluminescent element 23-2 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 23-1 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 41 described later and the source or drain of the writing transistor Tr2. Each scanning line WSL is connected to an output terminal of a light scanner 42, which will be described later, and a gate of a writing transistor Tr2. Each power supply line DSL is connected to the output end of the power supply circuit 33 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 supply line DSL. The terminals of the source and drain of the drive transistor Tr1 that are not connected to the power supply line DSL are connected to the anode (reflection layer 11) of the organic electroluminescent element 23-2. 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 23-2 side of the source and drain of the drive transistor Tr1.

(Driver 40)
The driver 40 has, for example, a horizontal selector 41 and a light scanner 42. The horizontal selector 41 applies, for example, an analog signal voltage Vsig input from the controller 30 to each signal line DTL in response to (synchronously) input of a control signal. The light scanner 42 scans a plurality of pixels 23 in predetermined units.

(Controller 30)
Next, the controller 30 will be described. For example, the controller 30 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 30 outputs, for example, the generated signal voltage Vsig to the horizontal selector 41. The controller 30 outputs a control signal to each circuit in the driver 40 in response to (synchronously) the synchronization signal Tin input from the outside, for example.

Next, the organic electroluminescent device 23-2 will be described with reference to FIGS. 13 and 1. FIG. 13 shows a schematic configuration example of the display panel 20.

The display panel 20 has a plurality of pixels 23 arranged in a matrix. As described above, the plurality of pixels 23 include, for example, a pixel 23 (23R) that emits red light, a pixel 23 (23G) that emits green light, and a pixel 23 (23B) that emits blue light. .. In the plurality of pixels 23, for example, the pixels 23R, the pixels 23G, and the pixels 23B constitute the pixels (color pixels 24) in the color display.

The pixel 23R includes an organic electroluminescent element 23-2 that emits red light. The pixel 23G includes an organic electroluminescent element 23-2 that emits green light. The pixel 23B includes an organic electroluminescent element 23-2 that emits blue light. The pixels 23R, 23G, and 23B have, for example, a striped arrangement. In each pixel 23, for example, pixels 23R, 23G, and 23B are arranged side by side in the column direction. Further, in each pixel row, for example, a plurality of pixels 23 that emit light of the same color are arranged in a row in the row direction.

The display panel 20 has a plurality of banks 25 extending in the row direction (banks 25 in the first embodiment) and two banks 22 extending in the column direction on the substrate 10. .. The plurality of banks 25 and the two banks 22 partition the pixel area 20A of the display panel 20. The plurality of banks 25 partition each pixel 23 in each color pixel 24. The two banks 22 define the end of each pixel row. That is, each pixel row is partitioned by two banks 25 and two banks 22.

[effect]
In the present embodiment, at least one of the plurality of organic electroluminescent elements 23-2 included in the display panel 20 is composed of the organic electroluminescent element 1 according to the above embodiment and its modified example. Therefore, it is possible to realize an organic electroluminescent device 2 having excellent light emitting characteristics and a long life.

<4. Application example>
[Application example 1]
Hereinafter, an application example of the organic electroluminescent device 2 described in the second embodiment will be described. The organic electric field light emitting device 2 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 a signal to a display device of an electronic device in all fields for displaying an image or a moving image.

FIG. 14 is a perspective view of the appearance of the electronic device 3 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 3 includes an organic electroluminescent device 2 on the display surface 320 of the electronic device 3. The organic electroluminescent device 2 is arranged so that the display panel 20 faces outward. In this application example, since the organic electroluminescent device 2 is provided on the display surface 320, it is possible to realize an electronic device 3 having excellent light emitting characteristics and a long life.

[Application example 2]
Hereinafter, an application example of the organic electroluminescent device 1 according to the above embodiment and a modified example thereof will be described. The organic electroluminescent element 1 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. 15 shows the appearance of an indoor lighting device to which the organic electroluminescent element 1 according to the above embodiment and its modification is applied. This illuminating device has, for example, an illuminating unit 410 configured to include one or a plurality of organic electroluminescent elements 1 according to the above embodiment and a modification thereof. 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 the light from the organic electroluminescent element 1 according to the above embodiment and its modified example. As a result, it is possible to realize a lighting device having excellent light emitting characteristics and a long life.

Although the present disclosure has been described above with reference to embodiments and application examples, the present disclosure is not limited to the embodiments and the like, and various modifications can be made. 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)
The first reflective layer and
The second reflective layer and
A monochromatic organic light emitting layer provided between the first reflective layer and the second reflective layer,
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer,
An organic electroluminescent device including a Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer.
(2)
The organic electroluminescent device according to (1), further comprising a Yb protective layer in contact with the second reflective layer side of the Ag electrode layer.
(3)
The organic electroluminescent device according to (1) or (2), wherein the Ag electrode layer is thinner than the second reflective layer.
(4)
The organic electroluminescence according to any one of (1) to (3), further comprising a film thickness adjusting layer having a higher resistance than the Ag electrode layer between the Ag electrode layer and the second reflective layer. element.
(5)
(1) to (4) further provided with wiring for electrically conducting the first reflective layer and the Ag electrode layer and supplying a current between the first reflective layer and the Ag electrode layer. The organic electroluminescent device according to any one.
(6)
The organic electroluminescent device according to any one of (1) to (5), wherein the second reflective layer and the Ag electrode layer are electrically conductive.
(7)
The second reflective layer and the Ag electrode layer are electrically conductive in a region opposite to the light emitting region of the organic light emitting layer.
The organic electroluminescent device according to (6).
(8)
The organic electroluminescent device according to any one of (1) to (7), wherein the distance between the first reflective layer and the second reflective layer is the optical path length in which the cavity is generated.
(9)
Equipped with multiple organic electroluminescent elements
At least one of the plurality of organic electroluminescent devices
The first reflective layer and
The second reflective layer and
A monochromatic organic light emitting layer provided between the first reflective layer and the second reflective layer,
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer,
An organic electroluminescent device having a Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer.
(10)
The plurality of organic electroluminescent elements are provided in the pixel region.
The organic electroluminescent device according to (9), wherein the second reflective layer and the Ag electrode layer are electrically conductive in a region around the pixel region.
(11)
Equipped with an organic electroluminescent device having a plurality of organic electroluminescent elements,
At least one of the plurality of organic electroluminescent devices
The first reflective layer and
The second reflective layer and
A monochromatic organic light emitting layer provided between the first reflective layer and the second reflective layer,
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer,
An electronic device having a Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer.
(12)
The first reflective layer and
The second reflective layer and
A monochromatic organic light emitting layer provided between the first reflective layer and the second reflective layer,
An electrode layer provided between the organic light emitting layer and the second reflective layer and having a film thickness thinner than that of the second reflective layer,
A film thickness adjusting layer having a higher resistance than the electrode layer, which is provided between the electrode layer and the second reflective layer,
An organic electroluminescent device including a wiring layer for supplying an electric current between the first reflective layer and the electrode layer.
(13)
The organic electroluminescent device according to (12), wherein the second reflective layer and the electrode layer are electrically conductive in a region around a pixel region.
(14)
The first reflective layer and
The second reflective layer and
A monochromatic organic light emitting layer provided between the first reflective layer and the second reflective layer,
An electrode layer provided between the organic light emitting layer and the second reflective layer,
A film thickness adjusting layer having a higher resistance than the electrode layer, which is provided between the electrode layer and the second reflective layer,
An organic electroluminescent device including a wiring layer for supplying an electric current between the first reflective layer and the electrode layer.
(15)
The organic electroluminescent device according to (14), wherein the film thickness of the electrode layer is relatively thin in the pixel region and relatively thick in the region around the pixel region.

1 ... organic electroluminescent element, 2 ... organic electroluminescent device, 3 ... electronic device, 10 ... substrate, 11 ... reflective layer, 12 ... hole injection layer, 13 ... hole transport layer, 14 ... organic light emitting layer, 14A ... Light emitting region, 15 ... electron transport layer, 16 ... electron injection layer, 17 ... cathode, 18 ... film thickness adjusting layer, 19 ... reflective layer, 20 ... display panel, 20A ... pixel region, 20B ... peripheral region, 21 ... electrode, 21A ... wiring layer, 21B ... electrode layer, 22,25 ... bank, 23,23R, 23G, 23B ... pixel, 23-1 ... pixel circuit, 23-2 ... organic electroluminescent element, 24 ... color pixel, 25 ... bank , 28 ... protective layer, 30 ... controller, 40 ... driver, 41 ... horizontal selector, 42 ... light scanner, 100 ... organic electroluminescent element, 310 ... housing, 320 ... display surface, 410 ... lighting unit, 420 ... ceiling, 430 ... wall, Cs ... holding capacity, DTL ... signal line, DSL ... power supply line, Tr1 ... drive transistor, Tr2 ... write transistor, Vgs ... gate-source voltage, Vsig ... signal voltage, WSL ... scanning line.

Claims (10)

The first reflective layer and
The second reflective layer and
A monochromatic organic light emitting layer provided between the first reflective layer and the second reflective layer,
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer,
A Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer is provided.
The Ag electrode layer is thinner than the second reflective layer and has a thickness of 0.1 nm or more and 10 nm or less.
The second reflective layer is an organic electroluminescent element having a size of 5 nm or more and 30 nm or less. The organic electroluminescent device according to claim 1, further comprising a Yb protective layer in contact with the second reflective layer side of the Ag electrode layer. The organic electroluminescent device according to claim 1 or 2, further comprising a film thickness adjusting layer having a higher resistance than the Ag electrode layer between the Ag electrode layer and the second reflective layer. Claims 1 to 3 further include wiring for electrically conducting the first reflective layer and the Ag electrode layer and supplying a current between the first reflective layer and the Ag electrode layer. The organic electroluminescent element according to any one item. The organic electroluminescent device according to any one of claims 1 to 4, wherein the second reflective layer and the Ag electrode layer are electrically conductive. The organic electroluminescent device according to claim 5, wherein the second reflective layer and the Ag electrode layer are electrically conductive in a region opposite to the light emitting region of the organic light emitting layer. The organic electroluminescent device according to any one of claims 1 to 6, wherein the distance between the first reflective layer and the second reflective layer is the optical path length in which the cavity is generated. Equipped with multiple organic electroluminescent elements
At least one of the plurality of organic electroluminescent devices
The first reflective layer and
The second reflective layer and
A monochromatic organic light emitting layer provided between the first reflective layer and the second reflective layer,
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer,
It has a Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer, and has.
The Ag electrode layer is thinner than the second reflective layer and has a thickness of 0.1 nm or more and 10 nm or less.
The second reflective layer is an organic electroluminescent device having a size of 5 nm or more and 30 nm or less. The plurality of organic electroluminescent elements are provided in the pixel region.
The organic electroluminescent device according to claim 8, wherein the second reflective layer and the Ag electrode layer are electrically conductive in a region around the pixel region. Equipped with an organic electroluminescent device having a plurality of organic electroluminescent elements,
At least one of the plurality of organic electroluminescent devices
The first reflective layer and
The second reflective layer and
A monochromatic organic light emitting layer provided between the first reflective layer and the second reflective layer,
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer,
It has a Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer, and has.
The Ag electrode layer is thinner than the second reflective layer and has a thickness of 0.1 nm or more and 10 nm or less.
The second reflective layer is an electronic device having a thickness of 5 nm or more and 30 nm or less.

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