WO2020012610A1

WO2020012610A1 - Display device, method of manufacturing same, and method of emitting light therefor

Info

Publication number: WO2020012610A1
Application number: PCT/JP2018/026377
Authority: WO
Inventors: 学二星; 伸一川戸; 時由梅田; 優人塚本; 裕士今田
Original assignee: シャープ株式会社
Priority date: 2018-07-12
Filing date: 2018-07-12
Publication date: 2020-01-16

Abstract

A display device (1) including a blue pixel (3B) and a cyan pixel (3C) that emits light which has a peak wavelength that is longer than that of blue light, wherein the blue pixel (3B) has a blue phosphorescent light emitting material-containing layer (34PB) and a blue fluorescent light emitting material-containing layer (34FB) as common layers common to the plurality of pixels (3), and the cyan pixel (3C) has the blue phosphorescent light emitting material-containing layer (34PB) as a light emitting layer.

Description

Display device, method of manufacturing the same, and method of emitting the same

The present invention relates to a display device, a manufacturing method thereof, and a light emitting method thereof.

Conventionally, color has been emphasized in organic EL display devices. Therefore, an organic EL display device using a fluorescent light emitting material having a wide color gamut as a light emitting material is widely used. However, fluorescent materials can only utilize 25% of singlet excitons for emission.

On the other hand, the internal quantum efficiency of the phosphorescent material is theoretically 100%. Therefore, in recent years, for example, as a white light emitting device, a display device using a phosphorescent light emitting material as a light emitting material has been developed (for example, see Patent Document 1).

Japanese Unexamined Patent Publication "JP-A-2014-241405 (published on December 25, 2014)"

However, the blue phosphorescent light-emitting material has a problem in color purity when it is used as a light-emitting material of a display device that emits blue light with a low blue chromaticity. At present, there is no known blue light-emitting material capable of achieving both low power consumption and a wide color gamut.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a pixel that emits blue light, which has a good balance between luminous efficiency and chromaticity, consumes less power than before, and emits blue light and An object of the present invention is to provide a display device capable of emitting light of a plurality of colors including cyan light, a manufacturing method thereof, and a light emitting method thereof.

In order to solve the above problem, a display device according to one embodiment of the present invention includes a first pixel that emits blue light and a second pixel that emits light having a peak wavelength longer than the blue light. Pixel, comprising a plurality of pixels including, each pixel, an anode, a cathode, formed between the anode and the cathode, a display device provided with an organic layer including a light-emitting layer, The first pixel is provided as a light-emitting layer, a first phosphorescent material-containing layer including a first phosphorescent material that emits cyan phosphorescent light, and a cathode side of the first phosphorescent material-containing layer, A fluorescent light-emitting material-containing layer containing a fluorescent light-emitting material that emits blue fluorescent light having a peak wavelength shorter than the cyan phosphorescence, and the second pixel includes the first pixel as the light-emitting layer. A phosphorescent material-containing layer, wherein the first phosphorescent material is contained; The layer is a common layer provided in common for the plurality of pixels. In the first pixel, the first phosphorescent material-containing layer and the fluorescent material-containing layer emit light, and in the second pixel, The first phosphorescent material-containing layer emits light.

In order to solve the above problem, a method for manufacturing a display device according to one embodiment of the present invention includes: a first pixel that emits blue light; and a light that has a peak wavelength longer than the blue light. A plurality of pixels including a second pixel, and each pixel is provided with an anode, a cathode, and an organic layer including a light-emitting layer formed between the anode and the cathode. The first pixel may include, as the light emitting layer, a first phosphorescent material-containing layer including a first phosphorescent material that emits cyan phosphorescent light, and a first phosphorescent material-containing layer including the first phosphorescent material-containing layer. A fluorescent light-emitting material-containing layer that includes a fluorescent light-emitting material that emits blue fluorescent light having a shorter peak wavelength than the cyan phosphorescence, and wherein the second pixel includes, as the light-emitting layer, A first phosphorescent material-containing layer; The light material-containing layer is a common layer provided in common for the plurality of pixels, and in the first pixel, the first phosphorescent material-containing layer and the fluorescent light-emitting material-containing layer each emit light, In two pixels, a method for manufacturing a display device in which the first phosphorescent material-containing layer emits light, wherein an anode forming step of forming the anode, an organic layer forming step of forming the organic layer, and forming the cathode The organic layer forming step, using a deposition mask having a mask opening common to the plurality of pixels, a common layer forming step of forming the common layer; Using a deposition mask provided with a corresponding mask opening, the first pixel includes a fluorescent light emitting material-containing layer forming step of forming the fluorescent light emitting material-containing layer, and the common layer forming step includes: 1 phosphorescent material It is characterized by comprising a first phosphorescent material containing layer forming step of forming a chromatic layer.

In order to solve the above problem, a light emitting method of a display device according to one embodiment of the present invention emits a first pixel that emits blue light and a light that has a peak wavelength longer than the blue light. A plurality of pixels including a second pixel, and each pixel is provided with an anode, a cathode, and an organic layer including a light-emitting layer formed between the anode and the cathode. The first pixel may include, as the light emitting layer, a first phosphorescent material-containing layer including a first phosphorescent material that emits cyan phosphorescent light, and a first phosphorescent material-containing layer including the first phosphorescent material-containing layer. A fluorescent light-emitting material-containing layer that includes a fluorescent light-emitting material that emits blue fluorescent light having a shorter peak wavelength than the cyan phosphorescence, and wherein the second pixel includes, as the light-emitting layer, A first phosphorescent material-containing layer; The light material-containing layer is a common layer provided in common for the plurality of pixels, and in the first pixel, the first phosphorescent material-containing layer and the fluorescent light-emitting material-containing layer each emit light, In the two pixels, the first phosphorescent material-containing layer emits light in a display device, wherein the first phosphorescent material-containing layer generates triplet excitons and emits the fluorescent light. A singlet exciton is generated in the light-emitting material-containing layer, light generated when the triplet exciton generated in the first phosphorescent light-emitting material-containing layer returns to the ground state, and light generated in the fluorescent light-emitting material-containing layer. And light generated when the singlet exciton returns to the ground state. The second pixel generates a triplet exciton in the first phosphorescent material-containing layer, and generates the first phosphorescent light. Ground state of triplet exciton generated in material-containing layer It is characterized by emitting light that occurs when the back.

According to one embodiment of the present invention, in a pixel that emits blue light, a plurality of colors including blue light and cyan light have a good balance between luminous efficiency and chromaticity, consume less power than a conventional device, and have a low power consumption. , A method of manufacturing the same, and a method of emitting the same.

FIG. 2 is a diagram schematically illustrating a schematic configuration of a light emitting layer unit of the organic EL display device according to the first embodiment together with a light emitting principle. FIG. 2 is a diagram illustrating a light emitting mechanism in a blue pixel of the organic EL display device according to the first embodiment. FIG. 3 is a diagram illustrating a light emitting mechanism in a cyan pixel of the organic EL display device according to the first embodiment. 2A is a diagram illustrating an energy band of a light emitting layer unit and each layer adjacent to the light emitting layer unit in a green pixel of the organic EL display device according to the first embodiment, and FIG. FIG. 4 is a diagram illustrating energy bands of a light emitting layer unit and each layer adjacent to the light emitting layer unit in a red pixel R of the display device. FIG. 3 is a diagram illustrating spectra of blue fluorescence, cyan phosphorescence, green phosphorescence, and red phosphorescence according to the first embodiment. FIG. 2 is a cross-sectional view illustrating a schematic configuration of a main part of the organic EL display device according to the first embodiment. FIGS. 3A to 3D are plan views illustrating a method of laminating each light-emitting material-containing layer constituting the light-emitting layer unit of the organic EL display device according to the first embodiment in the order of lamination. FIG. 5 is a cross-sectional view illustrating a schematic configuration of a main part of an organic EL display device according to a second embodiment. FIGS. 7A and 7B are plan views showing the steps of forming a hole transport layer and a hole transport layer of the organic EL display device according to Embodiment 2 in the order in which they are stacked. 5A to 5D are plan views showing a method of laminating the respective light emitting material-containing layers constituting the light emitting layer unit of the organic EL display device according to Embodiment 2 in the order of stacking. FIG. 4 is a diagram schematically illustrating a schematic configuration of a light emitting layer unit of an organic EL display device according to Embodiment 2 along with a light emission principle. FIG. 9 is a diagram illustrating a light emitting mechanism in a cyan pixel of the organic EL display device according to the second embodiment. FIG. 9 is a cross-sectional view illustrating a schematic configuration of a main part of an organic EL display device according to a third embodiment. 13 is a cross-sectional view illustrating another schematic configuration of a main part of the organic EL display device according to Embodiment 3. FIG. FIG. 14 is a diagram illustrating a light emitting mechanism in a blue pixel of the organic EL display device according to the fourth embodiment. FIG. 15 is a cross-sectional view illustrating a schematic configuration of a main part of an organic EL display device according to a fifth embodiment. FIG. 15 is a plan view showing a hole block layer forming step in the manufacturing process of the organic EL display device according to the fifth embodiment.

[Embodiment 1]
<Schematic Configuration of Organic EL Display>
FIG. 6 is a cross-sectional view illustrating a schematic configuration of a main part of the organic EL display device 1 according to the first embodiment. Hereinafter, the organic EL display device 1 will be described as an example of the display device.

(6) As shown in FIG. 6, the organic EL display device 1 has a plurality of pixels 3 that emit light of different colors (in other words, light having different peak wavelengths in the photoluminescence emission spectrum). The plurality of pixels 3 include a blue pixel 3B (first pixel) that emits blue light and a cyan pixel 3C (second pixel) that emits light having a peak wavelength longer than the peak wavelength of blue light. And a pixel (third pixel) that emits light having a peak wavelength longer than the peak wavelength of cyan light.

In the blue pixel 3B, a cyan phosphorescent material-containing layer 34PC (first phosphorescent material-containing layer) and a blue fluorescent light-emitting material-containing layer 34FB (fluorescent light-emitting material-containing layer) are provided as light-emitting layers. . The cyan phosphorescent material containing layer 34PC contains a cyan phosphorescent material (first phosphorescent material) that emits cyan phosphorescence. The blue fluorescent light emitting material-containing layer 34FB includes a blue fluorescent light emitting material (fluorescent light emitting material) that emits blue fluorescent light having a peak wavelength shorter than that of cyan light.

The cyan pixel 3C is provided with a cyan phosphorescent material-containing layer 34PC as a light-emitting layer.

３A third phosphorescent material-containing layer including a second phosphorescent material that emits phosphorescence having a peak wavelength longer than that of cyan light is provided as a light emitting layer in the third pixel. In addition, these light emitting layers will be described later in detail.

有機 The organic EL display device 1 according to the present embodiment has, as the third pixels, a green pixel 3G that emits green light and a red pixel 3R that emits red light. Thereby, the organic EL display device 1 displays a full-color image.

In the present embodiment, one pixel 2a is formed by the pixels 3 of three colors of the blue pixel 3B, the green pixel 3G, and the red pixel 3R. Further, one picture element 2b is formed by the three color pixels 3 of the cyan pixel 3C, the green pixel 3G, and the red pixel 3R. As shown in FIG. 7A described later, a plurality of picture elements 2 including a picture element 2a and a picture element 2b are provided in a matrix in the display area 1a.

In the present embodiment, the ratio between the blue pixel 3B and the cyan pixel 3C included in the organic EL display device 1 is 1: 1. This is merely an example, and the ratio between the blue pixel 3B and the cyan pixel 3C can be an arbitrary ratio according to the product characteristics required for the organic EL display device 1.

青色 A blue organic EL element 20B, which is an organic EL element 20 that emits blue (B) light, is disposed in the blue pixel 3B. In the cyan pixel 3C, a cyan organic EL element 20C, which is an organic EL element 20 that emits cyan (C) light, is arranged. In the green pixel 3G, a green organic EL element 20G, which is an organic EL element 20 that emits green (G) light, is disposed. In the red pixel 3R, a red organic EL element 20R, which is an organic EL element 20 that emits red (R) light, is arranged.

The organic EL display device 1 has a configuration in which, for example, a plurality of the above-described organic EL elements 20 of a plurality of colors are provided on a TFT (Thin Film Transistor) substrate 10. The plurality of organic EL elements 20 are covered with a sealing film 40. Note that a cover (not shown) may be provided on the sealing film 40 via an adhesive layer (not shown), for example.

(4) The TFT substrate 10 is a circuit substrate on which a TFT circuit including the TFT 12 (driving element) and the wiring 13 is formed. The TFT substrate 10 includes a support 11 having an insulating property, a TFT circuit provided on the support 11, and a flattening film 14 covering the TFT circuit.

The support 11 may be, for example, a flexible laminated film in which a lower film (not shown), a resin layer, and a barrier layer are provided in this order, or may be a glass substrate, a plastic substrate, or a plastic film. Good.

公知 A known TFT can be used as the TFT 12. The wiring 13 includes a plurality of gate wirings and a plurality of source wirings connected to the TFT 12. The gate wiring and the source wiring are arranged to be orthogonal to each other. A region surrounded by the gate wiring and the source wiring is the pixel 3.

The flattening film 14 is an organic insulating film made of a photosensitive resin such as an acrylic resin or a polyimide resin. The flattening film 14 flattens irregularities on the TFT circuit.

(6) As shown in FIG. 6, the organic EL element 20 has a configuration in which an organic EL layer 22 is sandwiched between an anode 21 and a cathode 23.

In the following, an example in which the anode 21 is a lower electrode, the cathode 23 is an upper electrode, and the anode 21, the organic EL layer 22, and the cathode 23 are stacked in this order from the lower layer will be described. However, the present embodiment is not limited to this, and the cathode 23 is used as a lower electrode, the anode 21 is used as an upper electrode, and the cathode 23, the organic EL layer 22, and the anode 21 are stacked in this order from the lower layer side. It may have a configuration. In this case, the stacking order or carrier transportability (hole transportability and electron transportability) of each functional layer constituting the organic EL layer 22 is reversed. Further, the materials forming the anode 21 and the cathode 23 are also inverted.

In the present embodiment, the anode 21 is an electrode (patterned anode) patterned in an island shape for each pixel 3. The cathode 23 is a solid electrode (common cathode) provided commonly to all the pixels 3.

端 The end of the anode 21 is covered with an edge cover 24. Each of the anodes 21 is connected to the TFT 12 via a contact hole 14a provided in the flattening film 14. The edge cover 24 is an insulating layer and is made of, for example, a photosensitive resin. The edge cover 24 prevents the concentration of the electrode and the thinning of the organic EL layer 22 at the end of the anode 21 to prevent a short circuit with the cathode 23. The edge cover 24 also functions as a pixel separation film so that current does not leak to the adjacent pixels 3.

The edge cover 24 is provided with an opening 24 a for each pixel 3. The exposed portion of the anode 21 and the organic EL layer 22 by the opening 24a is a light emitting region of each pixel 3, and the other region is a non-light emitting region.

感光 A photosensitive resin can be used for the edge cover 24. For the anode 21, for example, a transparent conductive film such as ITO (indium tin oxide) or IZO (indium zinc oxide), or a metal such as Au (gold), Pt (platinum), or Ni (nickel) is used. You. For the purpose of injecting electrons into the light emitting layer, the cathode 23 has a low work function metal such as Li (lithium), Ce (cerium), Ba (barium), and Al (aluminum), or a magnesium containing these metals. Alloys such as alloys (eg, MgAg) and aluminum alloys (eg, AlLi, AlCa, AlMg) are used.

(4) Light generated in the light emitting layer is extracted from one of the anode 21 and the cathode 23. As the electrode on the side from which light is extracted (the other electrode), a transparent or translucent translucent electrode is used. A reflective electrode is used for the electrode (one electrode) on the side from which light is not extracted. The reflective electrode may be formed of a reflective electrode material, or may be an electrode having a reflective layer. Further, each of the anode 21 and the cathode 23 may be formed as a single layer, or may have a laminated structure including a plurality of electrode materials.

Therefore, when the organic EL element 20 is a top emission type organic EL element, as shown in FIG. 6, the anode 21 may have a laminated structure of a reflective electrode 21a (reflective layer) and a translucent electrode 21b. Good.

Examples of the reflective electrode material include a black electrode material such as tantalum (Ta) or carbon (C), Al, Ag, gold (Au), an Al-Li alloy, an Al-neodymium (Nd) alloy, or an Al-silicon ( Reflective metal electrode materials such as Si) alloys; Further, as the translucent electrode, for example, the above-described transparent conductive film may be used, or a translucent electrode having a semi-transmissive reflective layer made of the above-described metal thin film may be used.

The reflective electrode 21a is independently formed with the same film thickness for each pixel 3 so as to be connected to the drain electrode of the TFT 12 in each pixel 3. On the other hand, in the translucent electrode 21b, the distance between the reflective electrode 21a (reflective layer) and the semi-transmissive reflective layer (cathode 23) is a distance that increases the intensity of the peak wavelength of light in the wavelength region of each color. As described above, the thickness is formed according to the peak wavelength of light in the wavelength region of each color emitted from each pixel 3. In other words, the distance between the reflective layer and the transflective layer is the optical path length at which the peak wavelength of the color light emitted from each pixel 3 resonates. Thereby, the color purity of light emitted from each pixel 3 is increased, and the chromaticity and luminous efficiency of light emission are improved.

The organic EL layer 22 is a functional layer including an organic layer, including at least a light emitting layer. In the present embodiment, the layers provided between the anode 21 and the cathode 23 are collectively referred to as an organic EL layer 22.

The organic EL layer 22 includes, from the anode 21 side, a light emitting layer unit 33 including a hole injection layer 31 (HIL), a hole transporting layer 32 (HTL), a plurality of light emitting material containing layers 34, and an electron transporting layer 35 (ETL). , And an electron injection layer 36 (EIL) are stacked in this order.

In FIG. 6, the case where the lower electrode is the anode 21 and the upper electrode is the cathode 23 is shown as an example. However, the present embodiment is not limited to this, and the lower electrode may be the cathode 23 and the upper electrode may be the anode 21. In this case, the stacking order or carrier transportability (hole transportability and electron transportability) of each functional layer constituting the organic EL layer 22 is reversed. Similarly, the materials forming the anode 21 and the cathode 23 are also inverted.

The hole injection layer 31, the hole transport layer 32, the electron transport layer 35, and the electron injection layer 36 are, for example, common layers common to all the pixels 3, and straddle all the pixels 3 so as to cover the upper surface of the edge cover 24. Accordingly, the entire display area is formed in a solid shape. However, the present embodiment is not limited to this. The hole injection layer 31, the hole transport layer 32, the electron transport layer 35, and the electron injection layer 36 may be provided in an island shape for each pixel 3.

The cyan phosphorescent material-containing layer 34PC is formed as a common layer common to all the pixels 3 so as to be solid over the entire display area over all the pixels 3. The blue fluorescent light emitting material containing layer 34FB is laminated on the cyan phosphorescent light emitting material containing layer 34PC corresponding to the blue pixel 3B, the green pixel 3G, and the red pixel 3R so as to be adjacent to the cyan phosphorescent light emitting material containing layer 34PC. I have. The blue fluorescent light emitting material containing layer 34FB is not provided in the cyan pixel 3C.

The light emitting layer unit 33 of the blue pixel 3B includes a light emitting material containing layer 34 composed of a cyan phosphorescent light emitting material containing layer 34PC (EML-PC) and a blue fluorescent light emitting material containing layer 34FB (EML-FB). Is formed. The blue fluorescent light emitting material containing layer 34FB is provided on the cathode 23 side of the cyan phosphorescent light emitting material containing layer 34PC. In the blue pixel 3B, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB emit light, respectively. That is, in the blue pixel 3B, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB are used as light-emitting layers, respectively.

The light emitting layer unit 33 of the cyan pixel 3C is formed of a single light emitting material containing layer 34 composed of a cyan phosphorescent light emitting material containing layer 34PC. In the cyan pixel 3C, the cyan phosphorescent material-containing layer 34PC emits light. That is, in the cyan pixel 3C, the cyan phosphorescent material-containing layer 34PC is used as a light emitting layer.

The green pixel 3G includes a common layer having a cyan phosphorescent material-containing layer 34PC and a blue fluorescent material-containing layer 34FB as a light-emitting layer, and a green phosphorescent material-containing layer 34PG (a second phosphorescent material-containing layer, EML). -PG). The green phosphorescent material-containing layer 34PG is made of a green phosphorescent material (second phosphorescent material) that emits green phosphorescence having a peak wavelength longer than the peak wavelength of cyan phosphorescence and the peak wavelength of blue fluorescence. Contains. The green phosphorescent material-containing layer 34PG is provided in an island shape for each green pixel 3G.

The red pixel 3R includes a common layer having a cyan phosphorescent material-containing layer 34PC and a blue fluorescent material-containing layer 34FB as a light-emitting layer, and a red phosphorescent material-containing layer 34PR (a second phosphorescent material-containing layer, EML). -PR). The red phosphorescent material-containing layer 34PR is a red phosphorescent material that emits red phosphorescence having a peak wavelength of cyan phosphorescence, a peak wavelength of blue fluorescence, and a peak wavelength longer than the peak wavelength of green phosphorescence. (A second phosphorescent material). The red phosphorescent material-containing layer 34PR is provided in an island shape for each red pixel 3R.

The green phosphorescent material-containing layer 34PG and the red phosphorescent material-containing layer 34PR are respectively located closer to the anode 21 than the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB. It is provided adjacent to the layer 34PC and the blue fluorescent light emitting material containing layer 34FB.

Therefore, the light emitting layer unit 33 of the green pixel 3G includes the green phosphorescent light emitting material containing layer 34PG, the cyan phosphorescent light emitting material containing layer 34PC, and the blue fluorescent light emitting material containing layer 34FB in this order from the anode 21 side. It has a configuration of being stacked adjacent to each other.

The light emitting layer unit 33 of the red pixel 3R includes a red phosphorescent light emitting material containing layer 34PR, a cyan phosphorescent light emitting material containing layer 34PC, and a blue fluorescent light emitting material containing layer 34FB in this order from the anode 21 side. It has a configuration in which it is stacked adjacently.

各 Each light emitting material containing layer 34 in the light emitting layer unit 33 is formed of a two-component system of a host material and a light emitting material (light emitting dopant material). However, the present embodiment is not limited to this, and each light emitting material containing layer 34 may be formed of a light emitting material alone. The material having the highest content ratio among the materials (components) in each light emitting material containing layer 34 may be a host material or a light emitting material.

The host material is capable of injecting holes and electrons, has a function of causing the light-emitting material to emit light by transporting the holes and electrons and recombining in the molecule. When the light emitting material containing layer 34 contains a host material, the host material has a carrier transport function and an exciton generation function, and the light emitting material has a light emitting function. As described above, the carrier transporting function and the light emitting function in the light emitting material containing layer 34 are functionally separated, and the light emitting material containing layer 34 is doped with a small amount of the light emitting material having a high emission quantum yield, so that the exciton transferred to the light emitting material is transferred to the light emitting material. Quickly emit light, and effective organic EL light emission is obtained. When a host material is used, the light emitting material is uniformly dispersed in the host material.

When a host material is used, the host material of the cyan phosphorescent material-containing layer 34PC has a triplet excitation level (T ₁ level) higher than that of the cyan phosphorescent material, and is higher than that of the cyan phosphorescent material. It is preferable to use a host material having a deepest highest occupied level (HOMO level). Similarly, it is preferable to use a host material having a higher T ₁ level than the green phosphorescent material and a deeper HOMO level than the green phosphorescent material for the host material of the green phosphorescent material-containing layer 34PG. . In addition, the host material of the red phosphorescent material containing layer 34PR, has a high T ₁ level position than the red phosphorescent light emitting material, it is preferable to use a host material having a deeper HOMO level than the red phosphorescent light-emitting material. Thereby, in each phosphorescent material-containing layer, holes can be efficiently injected into the phosphorescent material.

In addition, the host material of the blue fluorescent material-containing layer 34FB, blue fluorescent material has high singlet excitation level (S ₁ level position) than shallow lowest unoccupied molecular orbital level than blue fluorescent material ( It is preferable to use a host material having a LUMO level). Thereby, electrons can be efficiently injected into the blue fluorescent light emitting material in the blue fluorescent light emitting material containing layer 34FB.

In the present embodiment, in the blue pixel 3B, the hole transport of each layer in the organic EL layer 22 is set such that excitons are generated in the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB, respectively. Properties and electron transport properties are regulated.

Examples of the hole-transporting host material include 4,4′-bis [N-phenyl-N- (3 ″ -methylphenyl) amino] biphenyl (TPD) and 9,10-di (2-naphthyl) anthracene (ADN), 1,3-bis (carbazol-9-yl) benzene (mCP), 3,3′-di (9H-carbazol-9-yl) biphenyl (mCBP), 4,4 ′, 4 ″ -tris And a hole transporting material such as-(N-carbazolyl) -triphenylamine (TCTA).

Examples of the electron transporting host material include 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), bis [(2-diphenylphosphoryl) phenyl] ether (DPEPO), and 4,4′- Bis (2,2-diphenylvinyl) -1,1′-biphenyl (DPVBi), 2,2 ′, 2 ″-(1,3,5-benzindril) -tris (1-phenyl-1-H- Electron transporting materials such as benzimidazolyl) (TPBi) and bis (2-methyl-8-quinolinolate) -4- (phenylphenolate) aluminum (BAlq).

ホスト Bipolar transport host materials include, for example, bipolar transport materials such as 4,4'-bis (9-carbazoyl) -biphenyl (CBP).

Examples of blue fluorescent light emitting materials include 2,5,8,11-tetra-tert-butylperylene (TBPe) and bis [4- (9,9-dimethyl-9,10-dihydroacridine) phenyl] sulfone (DMAC). -DPS), perylene, 4,5-bis (carbazol-9-yl) -1,2-dicyanobenzene (2CzPN), 4,4'-bis (9-ethyl-3-carbazovinylene) -1,1'- A fluorescent material that emits blue light, such as biphenyl (BCzVBi), can be used.

Examples of red phosphorescent materials include tris (1-phenylisoquinoline) iridium (III) (Ir (piq) 3), bis (2-benzo [b] thiophen-2-yl-pyridine) (acetylacetonate) iridium (III) (Ir (btp) 2 (acac)), platinum (II) -octaethyl-porphyrin (PtOEP), bis (10-hydroxybenzo [h] quinolinate) beryllium (Bebq2) and the like.

Green phosphorescent materials include, for example, tris (2-phenylpyridyl) iridium (III) (Ir (PPy) 3), bis (2-phenylpyridine) (acetylacetonato) iridium (III) (Ir (PPy) 2 (Acac)) and the like.

Examples of cyan phosphorescent materials include oxadiazole dimer dye (Bis-DAPOXP) and spiro compound (2,2 ′, 7,7′-tetrakis (2,2′-diphenylvinyl) spiro-9,9 ′). -Bifluorene (spiro-DPVBi), tetraphenylbutadiene (TPB), pentaphenylcyclopentadiene (PPCP), triphenylamine (TPA), bis [2- (4,6-difluorophenyl) pyridinate-N, C2 '] iridium Picolinate (Flrpic)).

In the present embodiment, of the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB, the blue fluorescent light-emitting material-containing layer 34FB located on the cathode 23 side is the cyan phosphorescent material located on the anode 21 side. It is preferable to include a material having a HOMO level shallower than the light emitting material containing layer 34PC, and it is preferable to include a material having a LUMO level shallower than the cyan phosphorescent light emitting material containing layer 34PC.

Among the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB, the material contained in the cyan phosphorescent material-containing layer 34PC located on the anode 21 side is a green phosphorescent material and a red phosphorescent material. It is desirable to have a deeper HOMO level.

Further, of the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB, the triplet excitation level of the cyan phosphorescent material contained in the cyan phosphorescent material-containing layer 34PC located on the anode 21 side is It is desirable that the triplet excitation level of the green phosphorescent material is higher than the triplet excitation level of the red phosphorescent material.

The ratio (doping concentration) of each phosphorescent material in each phosphorescent material-containing layer can be arbitrarily set according to the type of the phosphorescent material, and is not particularly limited. It can be in the range of 1 to 40% by mass. The ratio (doping concentration) of the blue fluorescent light-emitting material in the blue fluorescent light-emitting material-containing layer 34FB can be arbitrarily set according to the type of the blue fluorescent light-emitting material, and is not particularly limited. For example, it can be in the range of 1 to 40% by mass.

In the present embodiment, the functional layers other than the respective luminescent material-containing layers constituting the luminescent layer unit 33 are not essential layers as the organic EL layer 22, but may be appropriately formed according to the required characteristics of the organic EL element 20. Good.

(4) The hole injection layer 31 is a layer containing a hole injection material and having a function of increasing the efficiency of hole injection into a light emitting material containing layer used as a light emitting layer. The hole transport layer 32 is a layer that contains a hole transport material and has a function of increasing the efficiency of transporting holes to the light emitting layer. The hole injection layer 31 and the hole transport layer 32 may be formed as layers independent of each other, or may be integrated as a hole injection layer and a hole transport layer. Further, it is not necessary to provide both the hole injection layer 31 and the hole transport layer 32, and only one of them (for example, only the hole transport layer 32) may be provided.

材料 A known material can be used as the material of the hole injection layer 31, the hole transport layer 32, or the hole injection layer and the hole transport layer, that is, the hole injection material or the hole transport material. Examples of these materials include naphthalene, anthracene, azatriphenylene, fluorenone, hydrazone, stilbene, triphenylene, benzene, styrylamine, triphenylamine, porphyrin, triazole, imidazole, oxadiazole, oxazole, polyarylalkane, phenylenediamine , Arylamines and their derivatives, thiophene-based compounds, polysilane-based compounds, vinylcarbazole-based compounds, aniline-based compounds, and other chain- or heterocyclic-conjugated monomers, oligomers, or polymers. More specifically, for example, N, N′-di (naphthalen-1-yl) -N, N′-diphenyl-benzidine (α-NPD), 2,3,6,7,10,11-hexacyano- 1,4,5,8,9,12-hexaazatriphenylene (HAT-CN), 1,3-bis (carbazol-9-yl) benzene (mCP), di- [4- (N, N-ditolyl- Amino) -phenyl] cyclohexane (TAPC), 9,10-diphenylanthracene-2-sulfonate (DPAS), N, N′-diphenyl-N, N ′-(4- (di (3-tolyl) amino) phenyl) -1,1'-biphenyl-4,4'-diamine (DNTPD), iridium (III) tris [N, N'-diphenylbenzimidazol-2-ylidene-C2, C2 '] (Ir (dpbic) 3 , 4,4 ', 4 "-tris- (N-carbazolyl) -triphenylamine (TCTA), 2,2-bis (p-trimellitooxyphenyl) propanoic anhydride (BTPD), bis [4- ( p, p-ditolylamino) phenyl] diphenylsilane (DTASi) and 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N- Phenylamino] triphenylamine (MTDATA) and the like.

In addition, the hole injection layer 31, the hole transport layer 32, and the hole injection layer / hole transport layer may be an intrinsic hole injecting material or an intrinsic hole transporting material which is not doped with impurities. Impurities may be doped for reasons such as enhancing conductivity.

The electron injection layer 36 is a layer that contains an electron injecting material and has a function of increasing the efficiency of electron injection into the light emitting layer. Further, the electron transport layer 35 is a layer containing an electron transport material and having a function of increasing the efficiency of electron transport to the light emitting layer. The electron injection layer 36 and the electron transport layer 35 may be formed as independent layers, or may be integrated as an electron injection layer and an electron transport layer. Further, it is not necessary to provide both the electron injection layer 36 and the electron transport layer 35, and only one (for example, only the electron transport layer 35) may be provided.

As the material of the electron injection layer 36, the electron transport layer 35, or the electron injection layer and the electron transport layer, that is, a known material can be used as the electron injection material or the material used as the electron transport material. Examples of these materials include quinoline, perylene, phenanthroline, bisstyryl, pyrazine, triazole, oxazole, oxadiazole, fluorenone, and derivatives and metal complexes thereof, lithium fluoride (LiF), and the like. More specifically, for example, bis [(2-diphenylphosphoryl) phenyl] ether (DPEPO), 4,7-diphenyl-1,10-phenanthroline (Bphen), 3,3′-bis (9H-carbazole-9) -Yl) biphenyl (mCBP), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 1,3,5-tris (N-phenylbenzimidazol-2-yl) benzene ( TPBI), 3-phenyl-4 (1'-naphthyl) -5-phenyl-1,2,4-triazole (TAZ), 1,10-phenanthroline, Alq (tris (8-hydroxyquinoline) aluminum), LiF, etc. Is mentioned.

封止 On the cathode 23 of the organic EL element 20, a sealing film 40 for sealing the organic EL element 20 is provided. The sealing film 40 protects the cathode 23 serving as the upper electrode, and prevents oxygen and moisture from entering the organic EL elements 20 from the outside. The sealing film 40 is provided so as to cover all the organic EL elements 20.

The sealing film 40 may be formed of an inorganic layer, and may include an inorganic layer (inorganic sealing layer) and an organic layer (organic sealing layer). For example, as an example, the sealing film 40 may include an organic layer, and a first inorganic layer and a second inorganic layer sandwiching the organic layer. The inorganic layer has a moisture-proof function of preventing intrusion of moisture, and functions as a barrier layer for preventing the organic EL element 20 from being deteriorated by moisture or oxygen. The organic layer is used as a buffer layer (stress relaxation layer). The organic layer performs stress relaxation of the inorganic layer having a large film stress, flattening by filling a step portion or a foreign substance on the surface of the organic EL element 20, and filling a hole of a pinhole.

Examples of the inorganic layer include a silicon oxide film, a silicon nitride film, a silicon oxynitride film, and a stacked film thereof. Examples of the organic layer include photosensitive resins such as an acrylic resin, an epoxy resin, and a silicone resin.

As described above, a cover body (not shown) may be provided on the sealing film 40 via an adhesive layer (not shown). The cover is a functional layer having at least one of a protection function, an optical compensation function, and a touch sensor function. The cover body may be a protective film functioning as a support when a carrier substrate such as a glass substrate is peeled off, or may be a hard coat layer such as a hard coat film, or a polarizing film and a touch sensor film. It may be a functional film.

<Manufacturing method of organic EL display device 1>
Next, a method for manufacturing the organic EL display device 1 will be described below with reference to FIGS. 6 and 7A to 7D.

FIGS. 7A to 7D show the light emitting material containing layers 34 constituting the light emitting layer unit 33 of the organic EL display device 1 according to the first embodiment (that is, the red phosphorescent light emitting material containing layer 34PR, the green phosphorescent light emission). It is a top view which shows the lamination method of the material containing layer 34PG, the cyan phosphorescent material containing layer 34PC, and the blue fluorescent light emitting material containing layer 34FB) in lamination order. 7A to 7D, the number of the pixels 3 (that is, the blue pixel 3B, the cyan pixel 3C, the green pixel 3G, and the red pixel 3R) is omitted for convenience of illustration.

The manufacturing process of the organic EL display device 1 according to the present embodiment includes a TFT substrate manufacturing process of manufacturing the above-described TFT substrate 10 and an organic EL device manufacturing process of forming the organic EL device 20 on the TFT substrate 10 (organic layer formation). Step) and a sealing step of sealing the organic EL element 20 manufactured in the organic EL element manufacturing step with a sealing film 40.

The organic EL element manufacturing process includes, for example, an anode forming process, a hole injecting layer forming process, a hole transporting layer forming process, a red phosphorescent material-containing layer forming process (second phosphorescent material-containing layer forming process), and green. Phosphorescent material-containing layer forming step (second phosphorescent material-containing layer forming step), cyan phosphorescent material-containing layer forming step (common layer forming step, first phosphorescent material-containing layer forming step), blue fluorescent light-emitting material containing It includes a layer forming step (a common layer forming step, a fluorescent light emitting material containing layer forming step), an electron transporting layer forming step, an electron injecting layer forming step, and a cathode forming step.

In the present embodiment, the organic EL element manufacturing process is performed, for example, in this order. In this embodiment, for example, in the green phosphorescent material-containing layer forming step and the cyan phosphorescent material-containing layer forming step, the cyan phosphorescent material-containing layer 34PC is closer to the cathode 23 than the green phosphorescent material-containing layer 34PG. The process is performed continuously so as to be formed adjacent to the green phosphorescent material-containing layer 34PG. In this embodiment, the cyan phosphorescent material-containing layer forming step and the blue fluorescent light-emitting material-containing layer forming step are performed by laminating the cyan phosphorescent light-emitting material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB adjacent to each other. Is performed continuously. Hereinafter, each of the above-described steps will be described.

First, as shown in FIG. 6, a photosensitive resin is applied on the support 11 on which the TFT circuit including the TFT 12 and the wiring 13 is formed, and is patterned by photolithography. A flattening film 14 is formed. Next, a contact hole 13 a for electrically connecting the anode 21 to the TFT 12 is formed in the flattening film 14. Thus, the TFT substrate 10 is manufactured (TFT substrate manufacturing process).

Next, the organic EL element 20 is formed on the TFT substrate 10 thus formed (organic EL element manufacturing step).

In the organic EL element manufacturing process, first, the anode 21 is formed on the TFT substrate 10 (anode forming process). The anode forming step according to the present embodiment includes a reflecting electrode forming step of forming the reflecting electrode 21a on the TFT substrate 10, and a light transmitting electrode forming step of forming the light transmitting electrode 21b on the reflecting electrode 21a. ing.

In the reflective electrode forming step, a reflective electrode 21a is formed on the TFT substrate 10 by a known method with a predetermined thickness. In the light-transmitting electrode forming step, a light-transmitting electrode 21b having a different thickness is pattern-formed for each pixel 3 on the reflective electrode 21a.

The organic EL device 20 according to the present embodiment is a microcavity (microresonator) type organic EL device. In such an organic EL device, the emitted light is multiple-reflected between the anode 21 and the cathode 23 and resonates, whereby the emission spectrum becomes steep and the emission intensity at a specific wavelength is amplified. In the example shown in FIG. 6, the optical path length is changed for each pixel 3 by setting the thickness of the translucent electrode 21b for each pixel 3. In this embodiment, the anodes 21 having a layer thickness corresponding to the display color of the pixels 3 are formed in a matrix on the TFT substrate 10 in this manner. Specifically, the anode 21 having the same layer thickness is formed in the blue pixel 3B and the cyan pixel 3C. Further, an anode 21 having a thickness different from that of the anode 21 forming the blue pixel 3B is formed in the green pixel 3G. Further, the anode 21 having a thickness different from both the thickness of the anode 21 forming the blue pixel 3B and the thickness of the anode 21 forming the green pixel 3G is formed in the red pixel 3R.

Next, the edge cover 24 is patterned to cover the end of the anode 21. Through the above steps, the anode 21 separated by the edge cover 24 for each pixel 3 is manufactured.

Next, the hole injection layer 31 and the hole transport layer 32 are vapor-deposited in this order over the entire display region 1a on the TFT substrate 10 on which the anode 21 is formed, using, for example, an open mask (the hole injection layer 31). Forming step, hole transport layer forming step). However, as described above, the hole injection layer 31 and the hole transport layer 32 are not essential layers, and may be formed in an island shape for each pixel 3.

Next, as shown in FIG. 7A, a red phosphorescent material-containing layer 34PR is formed in the red pixel 3R (a red phosphorescent material-containing layer forming step). The red phosphorescent material-containing layer 34PR is formed in a striped island shape on the hole transport layer 32 of the red pixel 3R by separate deposition using a deposition mask 200R provided with a mask opening 201R corresponding to the red pixel 3R. Formed.

{After that, as shown in FIG. 7B, the green phosphorescent material-containing layer 34PG is formed in the green pixel 3G (green phosphorescent material-containing layer forming step). The green phosphorescent material-containing layer 34PG is formed in a striped island shape on the hole transport layer 32 of the green pixel 3G by separate deposition using a deposition mask 200G provided with a mask opening 201G corresponding to the green pixel 3G. Is linearly deposited.

The red phosphorescent material-containing layer forming step and the green phosphorescent material-containing layer forming step may be performed in reverse order, but are preferably performed in this order. When these steps are performed in this order, for example, the host material of the green phosphorescent material-containing layer 34PG (EML-PG) shown in FIG. If the material having the highest content ratio is a hole-transporting material, the red phosphorescent material enters the green pixel 3G by any chance, and the red phosphorescent material-containing layer 34PR is formed below the green phosphorescent material-containing layer 34PG. Even if formed, electrons do not reach the red phosphorescent material-containing layer 34PR. For this reason, red color mixture does not occur in the green pixel 3G. Therefore, in this case, the deposition margin for preventing color mixing can be reduced.

Next, the red phosphorescent material-containing layer 34PR, the green phosphorescent material-containing layer 34PG, and the hole transport layer 32 that are not covered with the red phosphorescent material-containing layer 34PR and the green phosphorescent material-containing layer 34PG are covered. As shown in FIG. 7C, a cyan phosphorescent material-containing layer 34PC is formed on the entire display region 1a of the TFT substrate 10 (cyan phosphorescent material-containing layer forming step). The cyan phosphorescent material-containing layer 34PC is formed as a common light-emitting layer extending over the plurality of pixels 3 as described above. Therefore, as shown in FIG. 6C, an open mask having a mask opening 201B1 common to the plurality of pixels 3 is used as the vapor deposition mask 200B1 for forming the cyan phosphorescent material-containing layer.

Subsequently, as shown in FIG. 7D, a blue fluorescent light emitting material containing layer 34FB is formed on the blue pixel 3B, green pixel 3G, and red pixel 3R so as to cover the cyan phosphorescent material containing layer 34PC. (Blue fluorescent light emitting material containing layer forming step). The cyan phosphorescent material-containing layer 34PC is formed by separately applying vapor using a deposition mask 200C provided with a mask opening 201C corresponding to the blue pixel 3B, the green pixel 3G, and the red pixel 3R. Deposited on 34PC.

FIGS. 7A to 7D show an example in which the evaporation masks 200R, 200G, 200B, and 200C are evaporation masks for mask-fixed evaporation. However, the present embodiment is not limited to this, and these deposition masks 200R, 200G, 200B, and 200C have a mask opening corresponding to a part of the light emitting material containing layer 34 to be formed. May be used.

When the light emitting material containing layer 34 contains a host material, the light emitting material containing layer 34 is formed by co-evaporating the host material and the light emitting material (light emitting dopant material) constituting the light emitting material containing layer 34. Is done. The deposition ratio of each material can be adjusted by, for example, the deposition rate.

Then, for example, using an open mask, as shown in FIG. 6, the electron transport layer 35 and the electron injection layer 36 are displayed so as to cover the blue fluorescent light emitting material containing layer 34FB and the cyan phosphorescent light emitting material containing layer 34PC. An electron transport layer forming step and an electron injection layer forming step are formed in this order over the entire surface of the region 1a. However, as described above, the electron transport layer 35 and the electron injection layer 36 are not essential layers, and may be formed in an island shape for each pixel 3.

Next, the cathode 23 is formed on the entire display area 1a of the TFT substrate 10 so as to cover the electron injection layer 36. For forming the cathode 23, a vapor deposition method such as a vacuum deposition method, a CVD method, or a plasma CVD method may be used, or a sputtering method, a printing method, or the like may be used.

Next, the organic EL element 20 is sealed with the sealing film 40. The inorganic layer (inorganic sealing layer) can be formed, for example, by CVD. The organic layer (organic sealing layer) can be formed, for example, by applying an ink material to a region surrounded by a bank (not shown) (not shown) by an inkjet method or the like, and by, for example, UV curing.

(5) Then, if necessary, a functional film such as a polarizing film and a touch sensor film, or a cover such as a polarizing plate and a touch panel is attached.

<Light Emitting Method of Organic EL Display Device 1>
The organic EL display device 1 performs color display by selectively emitting the organic EL element 20 in each pixel 3 at a desired luminance using the TFT 12. Hereinafter, a light emitting method (display method) of the organic EL display device 1 will be described with reference to FIGS.

FIG. 1 is a view schematically showing a schematic configuration of the light emitting layer unit 33 of the organic EL display device 1 according to the first embodiment together with a light emitting principle. FIG. 2 is a diagram illustrating a light emitting mechanism in the blue pixel 3B of the organic EL display device 1 according to the first embodiment. FIG. 3 is a diagram illustrating a light emitting mechanism in the cyan pixel 3C of the organic EL display device 1 according to the first embodiment. FIG. 4A is a diagram illustrating an energy band of the light emitting layer unit 33 and each layer adjacent to the light emitting layer unit 33 in the green pixel 3G of the organic EL display device 1 according to the first embodiment, and FIG. 3) is a diagram illustrating the energy bands of the light emitting layer unit 33 and each layer adjacent to the light emitting layer unit 33 in the red pixel 3R of the organic EL display device 1 according to the first embodiment. FIG. 5 is a diagram illustrating spectra of blue fluorescence, cyan phosphorescence, green phosphorescence, and red phosphorescence according to the first embodiment. In FIG. 1, illustrations other than the light emitting layer unit 33 are omitted.

As shown in FIG. 1, in the organic EL display device 1 according to the present embodiment, holes (h ⁺ ) injected from the anode 21 into the organic EL layer 22 and electrons injected from the cathode 23 into the organic EL layer 22. (E ⁻ ) means that in the blue pixel 3B, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB are respectively recombined to generate excitons.

In the present embodiment, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB are stacked in this order from the anode 21 side. Therefore, of the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB, the cyan phosphorescent material-containing layer 34PC located on the anode 21 side is a hole transporting material or a hole transporting material. It is desirable to include a bipolar transport material containing a conductive material and an electron transport material, and it is desirable that the blue fluorescent light emitting material containing layer 34FB located on the cathode 23 side contains an electron transport material. More specifically, the host material in the cyan phosphorescent material containing layer 34PC is desirably a hole transporting material or a bipolar transporting material, and the host material in the blue fluorescent light emitting material containing layer 34FB is an electron transporting material. Desirably, it is a material. In this case, holes and electrons are easily bonded to each other in the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB, and excitons are easily generated in the respective layers.

Further, as shown in FIGS. 4A and 4B, the cyan phosphorescent material-containing layer 34PC (EML-FB) and the blue fluorescent material-containing layer 34FB (EML-PB) When the blue fluorescent light-emitting material-containing layer 34FB located on the anode 21 side contains a material having a HOMO level shallower than the cyan phosphorescent light-emitting material-containing layer 34PC located on the anode 21 side, the blue fluorescent light-emitting material located on the cathode 23 side Holes easily enter the containing layer 34FB.

In addition, as shown in FIGS. 4A and 4B, of the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB, the blue fluorescent light-emitting material-containing layer 34FB located on the cathode 23 side is formed. When a material having a LUMO level shallower than that of the cyan phosphorescent material-containing layer 34PC located on the anode 21 side is included, electrons easily enter the cyan phosphorescent material-containing layer 34PC located on the anode 21 side.

In the examples shown in FIGS. 4A and 4B, the blue fluorescent light emitting material containing layer 34FB has a HOMO level and a LUMO level higher than the cyan phosphorescent material (Filpic) of the cyan phosphorescent material containing layer 34PC. Contains a shallow blue fluorescent light emitting material (BCzVBi).

Therefore, in the blue pixel 3B, excitons are easily generated in the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB.

Table 1 shows the values of the HOMO level and LUMO level of the material of each layer shown in FIG. 4A used in this embodiment. Table 2 shows the values of the HOMO level and LUMO level of the material of each layer shown in FIG. 4B used in this embodiment.

As shown in FIG. 2, an exciton generated respectively in blue phosphorescent material containing layer 34PB and blue fluorescent material-containing layer 34FB is deactivated each light when returning to the ground state (S ₀ state) to release I do.

Therefore, the blue pixel 3B, cyan phosphorescent material containing layer triplet excited state generated in the 34PC of (T ₁ state) exciton (triplet excitons) of cyan caused when returning to S ₀ state and phosphorescence, blue fluorescent material exciton-containing layer singlet excited state generated in 34FB (S ₁ state) (singlet excitons) is blue; and a blue fluorescence generated when returning to S ₀ state Light is emitted.

In cyan pixel 3C, as shown in FIG. 3, when the excitons generated by the cyan color phosphorescent material containing layer 34PC triplet excited state (T ₁ state) (triplet excitons) returns to S ₀ state , And cyan light including cyan phosphorescent light is emitted.

On the other hand, in the green pixel 3G, as shown in FIG. 4A, of the cyan phosphorescent light emitting material containing layer 34PC and the blue fluorescent light emitting material containing layer 34FB, the anode 21 side (in other words, the green phosphorescent light emitting material containing layer 34FB). The material included in the cyan phosphorescent material-containing layer 34PC located on the 34PG side) has a HOMO level deeper than that of the green phosphorescent material (Ir (PPy) 3 in the example shown in FIG. 4A). Accordingly, the cyan phosphorescent material-containing layer 34PC functions as a hole blocking layer for the green phosphorescent material-containing layer 34PG.

In the green pixel 3G, the cyan phosphorescent material-containing layer 34PC located on the anode 21 side (green phosphorescent material-containing layer 34PG side) of the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB. Since the triplet excitation level of the cyan phosphorescent material contained in is higher than the triplet excitation level of the green phosphorescent material, the cyan phosphorescent material-containing layer 34PC and the blue phosphorescent material are contained from the green phosphorescent material. Energy is not easily transferred to the layer 34FB.

For this reason, as shown in FIG. 1, the holes injected from the anode 21 into the organic EL layer 22 and the electrons injected from the cathode 23 into the organic EL layer 22 cause the green pixel 3G to contain the green phosphorescent material. Recombination occurs only in the layer 34PG to generate excitons. As a result, the green pixel 3G, a green phosphorescent green phosphorescent material containing layer T ₁ state generated by 34PG exciton (triplet excitons) occurs when returning to S ₀ state is emitted.

Similarly, in the red pixel 3R, as shown in FIG. 4B, of the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB, the anode 21 side (in other words, the red phosphorescent material-containing layer 34PC). The material included in the cyan phosphorescent material-containing layer 34PC located on the layer 34PR side has a HOMO level deeper than that of the red phosphorescent material (Ir (pip) 3 in the example shown in FIG. 4B). By doing so, the cyan phosphorescent material-containing layer 34PC functions as a hole blocking layer for the red phosphorescent material-containing layer 34PR.

In the red pixel 3R, the cyan phosphorescent material-containing layer 34PC located on the anode 21 side (the red phosphorescent material-containing layer 34PR side) of the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB. Since the triplet excitation level of the cyan phosphorescent material contained in is higher than the triplet excitation level of the red phosphorescent material, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material Energy is not easily transferred to the layer 34FB.

For this reason, as shown in FIG. 1, the holes injected from the anode 21 into the organic EL layer 22 and the electrons injected from the cathode 23 into the organic EL layer 22 cause the red pixel 3R to contain the red phosphorescent material. Recombination occurs only in the layer 34PR to generate excitons. As a result, the red pixel 3R, red phosphorescent red phosphorescent material containing layer T ₁ state generated by 34PR exciton (triplet excitons) occurs when returning to S ₀ state is emitted.

As described above, in the green pixel 3G and the red pixel 3R, no exciton is generated in the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB, and the cyan phosphorescent material and the blue fluorescent material do not emit light. . As a result, in the green pixel 3G, only the green phosphorescent material emits light, and in the red pixel 3R, only the red phosphorescent material emits light.

<Effect>
The internal quantum efficiency of a cyan phosphorescent material is theoretically 100%, whereas the internal quantum efficiency of a blue fluorescent light-emitting material is as low as 25%. For this reason, the peak intensity of emission of blue fluorescent light is extremely lower than that of cyan phosphorescent light. On the other hand, blue fluorescence has a shorter wavelength and deeper blue chromaticity than cyan phosphorescence. The shorter the wavelength, the less luminance is required for white balance.

Therefore, in the present embodiment, as described above, in the blue pixel 3B, although the cyan chromaticity is shallow, the internal quantum efficiency is theoretically 100%, which is higher than that of the cyan phosphorescent material. A fluorescent light emitting material having low internal quantum efficiency but deep blue chromaticity is laminated to emit light. Further, the cyan phosphorescent material emits light in the cyan pixel 3C.

In the present embodiment, as described above, the exciton is generated in each of the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB, so that the phosphorescent light emitted from the cyan phosphorescent material-containing layer 34PC is generated. The mixed light with the fluorescent light emitted from the blue fluorescent light emitting material containing layer 34FB is emitted from the blue pixel 3B. On the other hand, by generating excitons from the cyan phosphorescent material-containing layer 34PC, phosphorescence emitted from the cyan phosphorescent material-containing layer 34PC is emitted from the cyan pixel 3C.

Thus, although blue chromaticity is inferior (that is, shallower) as compared with the case where the blue pixel 3B emits only blue fluorescent light, the blue color is compared with the case where the blue pixel 3B emits only cyan phosphorescent light. It is possible to provide the organic EL display device 1 having a high degree (that is, deep) and capable of reducing power consumption as compared with the case where the blue pixel 3B emits only blue fluorescent light.

As described above, according to the present embodiment, in the blue pixel 3 </ b> B, the organic light emitting device can emit a plurality of lights including the blue light with a good balance between the luminous efficiency and the chromaticity, and with less power consumption than the related art. An EL display device 1 can be provided. Further, according to the present embodiment, the balance between the luminous efficiency and the chromaticity can be achieved by adjusting the ratio between the blue pixel 3B and the cyan pixel 3C. Therefore, device design according to product characteristics such as emphasis on power consumption and color gamut becomes possible.

According to the present embodiment, as described above, the efficiency can be improved as compared with the case where only the blue fluorescent light emitting material is used as the blue light emitting material. As described above, even if the cyan phosphorescent material-containing layer 34PC is provided in common for each pixel 3, an increase in power consumption due to the common use can be suppressed. For this reason, according to this embodiment, as described above, the cyan phosphorescent material-containing layer 34PC can be provided in common for each pixel 3, and it is easy to cope with higher definition of the display device. .

In particular, the blue pixel 3B is a probability of 25% that excitons in the blue fluorescent material-containing layer 34FB is generated as S ₁ state, due to the poor internal quantum efficiency, it is desired to increase the possible opening. However, the larger the opening is, the smaller the vapor deposition margin is, and the accuracy of coating becomes a problem. However, according to the present embodiment, as described above, by providing the cyan phosphorescent material-containing layer 34PC in common for the plurality of pixels 3, the aperture ratio of the blue pixel 3B can be increased, and the lifetime can be increased. Can be achieved. Further, according to the present embodiment, as described above, the cyan phosphorescent material-containing layer 34PC is provided in common for the plurality of pixels 3 so that the cyan phosphorescent material-containing layer 34PC can be formed with high definition. It does not require a simple evaporation mask. In addition, it is technically difficult to separately apply RGBC using a very fine deposition mask. According to this embodiment, only the blue fluorescent light emitting material containing layer 34FB, the green phosphorescent light emitting material containing layer 34PG in the green pixel 3G, and the red phosphorescent light emitting material containing layer 34PR in the red pixel 3R need to be separately applied. Therefore, the number of times of application can be suppressed to three times. Therefore, the manufacture of the organic EL display device 1 is facilitated.

<Modification 1>
In this embodiment, as shown in FIGS. 1 to 4A and FIG. 4B and FIG. 5, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB are The case where the layers are sequentially stacked has been described as an example. However, the present embodiment is not limited to this, and the blue fluorescent light emitting material containing layer 34FB and the cyan phosphorescent light emitting material containing layer 34PC may be provided in this order from the anode 21 side.

However, as described above, the material included in the cyan phosphorescent material-containing layer 34PC has a deeper HOMO level than the green phosphorescent material and the red phosphorescent material, and the cyan phosphorescent material-containing layer 34PC has a green phosphorescent material. It functions as a hole blocking layer for the light emitting material containing layer 34PG and the red phosphorescent light emitting material containing layer 34PR.

(4) As the host material in the cyan phosphorescent material-containing layer 34PC, a hole transporting material or a bipolar transporting material is used. Therefore, the cyan phosphorescent material-containing layer 34PC has a high hole-transport property.

On the other hand, the blue fluorescent light-emitting material-containing layer 34FB has an electron mobility higher than the hole mobility and has an electron transporting property. Therefore, the blue fluorescent light-emitting material-containing layer 34FB also functions as an electron transport layer, and electrons flow easily.

Further, as shown in Tables 1 and 2 and FIGS. 4A and 4B, the host material and the light emitting material (light emitting dopant material) included in the cyan phosphorescent material containing layer 34PC are blue fluorescent light emitting. The gap (band gap) between the HOMO level and the LUMO level of the host material and the light-emitting material (light-emitting dopant material) included in the material-containing layer 34FB is large. Therefore, electrons can be efficiently transferred from the blue fluorescent light emitting material containing layer 34FB to the cyan phosphorescent light emitting material containing layer 34PC, and the blue pixel 3B contains the blue fluorescent light emitting material from the cyan phosphorescent light emitting material containing layer 34PC. Holes can be efficiently moved to the layer 34FB.

Therefore, it is more preferable that the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB are stacked in this order from the anode 21 side.

<Modification 2>
Further, in the present embodiment, the case where the green pixel 3G and the red pixel 3R are provided as the third pixel has been described as an example, but the present embodiment is not limited to this. The third pixel may be a pixel that emits light of a color having a peak wavelength longer than the peak wavelength of cyan light, such as yellow (Y) light, magenta (M) light, or the like. There is no particular limitation. Further, the picture element 2a and the picture element 2b do not necessarily need to be constituted by the pixels 3 of three colors, and may be constituted by the pixels 3 of two colors or four colors.

<Modification 3>
In the organic EL display device 1, the cathode 23 may be provided on the surface on the TFT substrate 10 side, and the anode 21 may be provided on the sealing film 40 side.

[Embodiment 2]
In the present embodiment, differences from the first embodiment will be described. Components having the same functions as the components described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, the organic EL display device 1 will be described as an example of the display device.

<Schematic Configuration of Organic EL Display>
FIG. 8 is a cross-sectional view illustrating a schematic configuration of a main part of the organic EL display device 1 according to the second embodiment.

As shown in FIG. 8, the organic EL display device 1 according to the second embodiment includes a blue pixel 3B, a cyan pixel 3C, a green pixel 3G, and a red pixel 3R, as in the first embodiment. The overall configuration of the organic EL display device 1 is substantially the same as the overall configuration of the organic EL display device 1 according to the first embodiment. For example, each configuration of the blue pixel 3B, the green pixel 3G, and the red pixel 3R is the same as each configuration of the blue pixel 3B, the green pixel 3G, and the red pixel 3R according to the first embodiment. However, in the present embodiment, the configuration of the light emitting layer unit 33 of the cyan pixel 3C is different from the configuration of the light emitting layer unit 33 of the cyan pixel 3C according to the first embodiment.

In the present embodiment, the configuration of the light emitting layer included in the cyan pixel 3C is the same as the configuration of the light emitting layer included in the blue pixel 3B. Therefore, the cyan pixel 3C has a cyan phosphorescent material-containing layer 34PC as the light-emitting layer as in the first embodiment, and further has a blue fluorescent light-emitting material-containing layer 34FB different from the first embodiment.

In the present embodiment, the light emitting layer unit 33 of the cyan pixel 3C, like the light emitting layer unit 33 of the blue pixel 3B, includes a cyan phosphorescent material containing layer 34PC and a blue fluorescent material containing layer 34FB. The light-emitting material-containing layer 34 is formed. Thereby, in the cyan pixel 3C, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB emit light, respectively. That is, in the cyan pixel 3C, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB are used as light-emitting layers, respectively.

In the organic EL display device 1 according to the present embodiment, the blue fluorescent light emitting material containing layer 34FB and the cyan phosphorescent light emitting material containing layer 34PC serve as a common layer common to all the pixels 3 and extend over all the pixels 3. The entire area is formed in a solid shape. In other words, the common layer further includes the blue fluorescent light emitting material containing layer 34FB in addition to the cyan phosphorescent light emitting material containing layer 34PC.

The organic EL layer 22 has a hole transport layer 32B (first hole transport layer) and a hole transport layer 32C (first hole transport layer) provided separately for the blue pixel 3B and the cyan pixel 3C between the light emitting layer and the anode 21. (A second hole transport layer). The hole transport layer 32B is provided commonly to the green pixel 3G and the red pixel 3R in addition to the blue pixel 3B. Not limited to this, the organic EL layer 22 may include a not-shown hole transport layer 32G (third hole transport layer) and a hole transport layer 32R (fourth hole transport layer) provided in the green pixel 3G and the red pixel 3R, respectively. ).

では In the present embodiment, the thickness of the hole transport layer 32B is different from the thickness of the hole transport layer 32C. Specifically, the thickness of the hole transport layer 32C is larger than the thickness of the hole transport layer 32B. The difference between the thickness of the hole transport layer 32C and the thickness of the hole transport layer 32B is preferably 5 to 25 nm.

<Manufacturing method of organic EL display device 1>
FIGS. 9A and 9B are plan views showing the steps of forming the hole transport layer 32B and the hole transport layer 32C of the organic EL display device 1 according to the second embodiment in the order in which they are stacked. 9A and 9B, the number of pixels 3 is omitted for convenience of illustration. FIGS. 10A to 10D are plan views showing a method of laminating the respective light emitting material containing layers 34 constituting the light emitting layer unit 33 of the organic EL display device 1 according to the second embodiment in the order of stacking. In FIGS. 10A to 10D, the number of pixels 3 is omitted for convenience of illustration.

Most of the manufacturing process of the organic EL display device 1 according to the present embodiment is the same as the manufacturing process of the organic EL display device 1 according to the first embodiment. However, the present embodiment is different from the first embodiment in the hole transport layer forming step and the cyan phosphorescent material-containing layer forming step.

In this embodiment, the hole transport layer forming step includes a step of forming the hole transport layer 32B (first hole transport layer forming step) and a step of subsequently forming the hole transport layer 32C (second hole transport layer). Transport layer forming step). When performing the hole transport layer forming step, first, a common hole transport layer 32B is formed for the blue pixel 3B, the green pixel 3G, and the red pixel 3R. The hole transport layer 32B is formed by separate deposition using a deposition mask 210B provided with a mask opening 211B corresponding to the blue pixel 3B, the green pixel 3G, and the red pixel 3R as shown in FIG. Are formed on the hole injection layer 31 in a stripe island shape.

Next, a hole transport layer 32C having a thickness larger than the thickness of the hole transport layer 32B is formed in the cyan pixel 3C. The hole transport layer 32C is formed on the hole injection layer 31 by separate deposition using a deposition mask 210C provided with a mask opening 211C corresponding to the cyan pixel 3C as shown in FIG. 9B. Are formed in a stripe island shape.

In this embodiment, the red phosphorescent material-containing layer 34PR and the green phosphorescent material-containing layer are formed using the evaporation masks 200R, 200G, and 200C shown in FIGS. 34PG and a cyan phosphorescent material-containing layer 34PC are formed. Subsequently, a blue fluorescent light emitting material containing layer 34FB is formed on the entire display region 1a of the TFT substrate 10 as shown in FIG. 10D so as to cover the cyan phosphorescent light emitting material containing layer 34PC (blue fluorescent light emitting layer 34FB). Material-containing layer forming step). In the present embodiment, the blue fluorescent light emitting material containing layer 34FB is formed as a common light emitting layer extending over a plurality of pixels 3. Therefore, as shown in FIG. 10D, an open mask having a mask opening 201B2 common to the plurality of pixels 3 is used as the vapor deposition mask 200B2 for forming the blue fluorescent light emitting material-containing layer.

The cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB have the same pattern in plan view. For this reason, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB may be continuously formed using the same evaporation mask as the evaporation mask 200C and the evaporation mask 200B2. It may be formed using a mask.

<Light Emitting Method of Organic EL Display Device 1>
FIG. 11 is a diagram schematically illustrating a schematic configuration of the light emitting layer unit 33 of the organic EL display device 1 according to the second embodiment together with a light emitting principle. FIG. 12 is a diagram illustrating a light emitting mechanism in the cyan pixel 3C of the organic EL display device 1 according to the second embodiment. In FIG. 11, illustrations other than the light emitting layer unit 33 are omitted.

発光 The light emission mechanism of the blue pixel 3B, the green pixel 3G, and the red pixel 3R is the same as that of the first embodiment. Therefore, detailed description will not be repeated.

As shown in FIG. 11, the holes (h ⁺ ) injected from the anode 21 into the organic EL layer 22 and the electrons (e ⁻ ) injected from the cathode 23 into the organic EL layer 22 in the cyan pixel 3C. The cyan phosphorescent light emitting material containing layer 34PC and the blue fluorescent light emitting material containing layer 34FB recombine with each other to generate excitons.

Further, as shown in FIG. 12, the cyan pixel 3C, the excitons generated respectively in blue phosphorescent material containing layer 34PB and blue fluorescent material-containing layer 34FB, deactivated to the ground state (S ₀ state) Each emits light when returning to. In cyan pixel 3C, a phosphorescent cyan excitons cyan phosphorescent material containing layer triplet excited state generated in the 34PC (T ₁ state) (triplet excitons) occurs when returning to S ₀ state , the light including the blue fluorescence produced when the blue fluorescent material exciton-containing layer singlet excited state generated in 34FB (S ₁ state) (singlet excitons) returns to S ₀ state, the emitted You.

As described above, the light emitting mechanism of the cyan pixel 3C is the same as the light emitting mechanism of the blue pixel 3B. However, since the thickness of the hole transport layer 32C is larger than the thickness of the hole transport layer 32B, the intensity of the cyan phosphorescence generated in the cyan pixel 3C is lower than the intensity of the cyan phosphorescence generated in the blue pixel 3B. Higher than. Thereby, blue light including weaker cyan phosphorescence and blue fluorescence is emitted from the blue pixel 3B, while stronger cyan phosphorescence and blue fluorescence are emitted from the cyan pixel 3C. Cyan light is emitted. Therefore, according to the present embodiment, it is possible to realize the organic EL display device 1 having each pixel 3 of RBGC. Further, similarly to the first embodiment, by appropriately changing the ratio of the blue pixel 3B and the cyan pixel 3C, it is possible to realize the organic EL display device 1 flexibly corresponding to required product characteristics.

In the present embodiment, at least one of the thickness and the material of the hole transport layer 32B and the hole transport layer 32C may be different. For example, the material of the hole transport layer 32B and the material of the hole transport layer 32C may be different. The material of the hole transport layer 32B is a general material for a hole transport layer such as α-NPD. On the other hand, the material of the hole transport layer 32C is a material having a higher ionization potential energy (having a deeper HOMO level) than the material of the hole transport layer 32B, and is, for example, MTDATA or mCP. Also in this case, the same effect as when the thickness of the hole transport layer 32C is different from the thickness of the hole transport layer 32B can be obtained. A deep HOMO level is synonymous with a large negative value.

[Embodiment 3]
In the present embodiment, differences from the second embodiment will be described. Components having the same functions as the components described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, the organic EL display device 1 will be described as an example of the display device.

<Schematic Configuration of Organic EL Display>
FIG. 13 is a cross-sectional view illustrating a schematic configuration of a main part of the organic EL display device 1 according to the third embodiment. As shown in FIG. 13, the organic EL display device 1 according to the second embodiment includes a blue pixel 3B, a cyan pixel 3C, a green pixel 3G, and a red pixel 3R, as in the second embodiment. The overall configuration of the organic EL display device 1 is substantially the same as the overall configuration of the organic EL display device 1 according to the second embodiment. For example, each configuration of the blue pixel 3B, the green pixel 3G, and the red pixel 3R is the same as each configuration of the blue pixel 3B, the green pixel 3G, and the red pixel 3R according to the first embodiment. However, in the present embodiment, the configuration of the cyan pixel 3C is different from the configuration of the cyan pixel 3C according to the second embodiment.

Similarly to the second embodiment, the light emitting layer of the cyan pixel 3C has both the cyan phosphorescent material containing layer 34PC and the blue fluorescent material containing layer 34FB. Therefore, in the cyan pixel 3C, similarly to the second embodiment, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB are used as light-emitting layers. Further, the blue fluorescent light emitting material containing layer 34FB and the cyan phosphorescent light emitting material containing layer 34PC are common layers common to all the pixels 3 and extend over all the pixels 3 as in the second embodiment. It is formed in a solid shape.

構成 The configuration of the hole transport layer 32 is the same as that of the first embodiment. That is, the organic EL layer 22 has the hole transport layer 32 formed in a solid shape over the entire display region across the pixels 3 between the light emitting layer and the anode 21.

では In the present embodiment, the thickness of the anode 21 is different from each other in the blue pixel 3B and the cyan pixel 3C. Specifically, the film thickness of the light-transmitting electrode 21b forming the cyan pixel 3C is larger than the film thickness of the light-transmitting electrode 21b forming the blue pixel 3B. The difference between the thickness of the translucent electrode 21b forming the cyan pixel 3C and the thickness of the translucent electrode 21b forming the blue pixel 3B is preferably 5 to 10 nm.

<Manufacturing method of organic EL display device 1>
Most of the manufacturing process of the organic EL display device 1 according to the present embodiment is the same as the manufacturing process of the organic EL display device 1 according to the first embodiment. However, in this embodiment, the anode forming step and the cyan phosphorescent material-containing layer forming step are different from those of the first embodiment.

In the anode forming step according to the present embodiment, the anodes 21 having different thicknesses are formed on the blue pixel 3B and the cyan pixel 3C, respectively. Specifically, the anode 21 having the first thickness is formed on the blue pixel 3B, and the anode 21 having the second thickness larger than the first thickness is formed on the cyan pixel 3C. Since the step of forming the cyan phosphorescent material-containing layer is the same as that of the second embodiment, the detailed description will not be repeated.

<Light Emitting Method of Organic EL Display Device 1>
The light emitting mechanism of each pixel 3 according to the present embodiment is the same as that of the second embodiment, and thus the detailed description will not be repeated. In the present embodiment, the light emitting mechanism of the cyan pixel 3C is the same as the light emitting mechanism of the blue pixel 3B. However, since the thickness of the anode 21 forming the cyan pixel 3C is larger than the thickness of the anode 21 forming the blue pixel 3B, the intensity of the cyan phosphorescence generated in the cyan pixel 3C is reduced in the blue pixel 3B. It is higher than the intensity of the resulting cyan phosphorescence. Thereby, blue light including weaker cyan phosphorescence and blue fluorescence is emitted from the blue pixel 3B, while stronger cyan phosphorescence and blue fluorescence are emitted from the cyan pixel 3C. Cyan light is emitted. Therefore, according to the present embodiment, it is possible to realize the organic EL display device 1 having each pixel 3 of RBGC. Further, similarly to the first embodiment, by appropriately changing the ratio of the blue pixel 3B and the cyan pixel 3C, it is possible to realize the organic EL display device 1 flexibly corresponding to required product characteristics.

<Modification>
FIG. 14 is a cross-sectional view illustrating another schematic configuration of a main part of the organic EL display device 1 according to the third embodiment. As shown in FIG. 14, the organic EL display device 1 may have a configuration in which the material of the anode 21 is different between the blue pixel 3B and the cyan pixel 3C. More specifically, in the organic EL display device 1 shown in FIG. 14, the anode 21 forming the blue pixel 3B has a reflective electrode 21a and a translucent electrode 21b, and the anode 21 forming the cyan pixel 3C is a reflective pixel. It has an electrode 21a, a translucent electrode 21b, and a translucent electrode 21c. In the cyan pixel 3C, it is formed on the light transmitting electrodes 21c and 21b. As described above, the anode 21 forming the blue pixel 3B has one layer of the light-transmitting electrode 21b, and the anode 21 forming the cyan pixel 3C has two layers of the light-transmitting electrode 21b and the light-transmitting electrode. 21c.

In FIG. 14, the material of the translucent electrode 21c is different from the material of the translucent electrode 21b. For example, the material of the translucent electrode 21b is ITO, and the material of the translucent electrode 21c is IZO. As described above, the anode 21 forming the blue pixel 3B has a single-layer structure made of an ITO layer, and the anode 21 forming the cyan pixel 3C has a laminated structure made of an ITO layer and an IZO layer.

膜厚 In the blue pixel 3B and the cyan pixel 3C, the film thickness of the translucent electrode 21b is the same. Accordingly, the sum of the thickness of the light-transmitting electrode 21b constituting the cyan pixel 3C and the thickness of the light-transmitting electrode 21c is larger than the thickness of the light-transmitting electrode 21b constituting the blue pixel 3B. As described above, in the organic EL display device 1 shown in FIG. 14, both the film thickness and the material of the anode 21 are different between the blue pixel 3B and the cyan pixel 3C.

発光 The light emission mechanism of each pixel 3 in this modification is the same as that of the organic EL display device 1 shown in FIG. Also in this modification, similarly to the organic EL display device 1 shown in FIG. 13, blue light including weaker cyan phosphorescence and blue fluorescence is emitted from the blue pixel 3B, while the cyan pixel 3C Emits cyan light including stronger cyan phosphorescence and blue fluorescence. Therefore, according to the present modification, the organic EL display device 1 having each pixel 3 of RBGC can be realized. Further, similarly to the first embodiment, by appropriately changing the ratio of the blue pixel 3B and the cyan pixel 3C, it is possible to realize the organic EL display device 1 flexibly corresponding to required product characteristics.

In the present embodiment, at least one of the material and the thickness of the anode 21 may be different between the blue pixel 3B and the cyan pixel 3C. Therefore, for example, the film thickness of the light-transmitting electrode 21b forming the anode 21 of the blue pixel 3B is determined by the film thickness of the light-transmitting electrode 21b forming the anode 21 of the cyan pixel 3C and the film thickness of the light-transmitting electrode 21c. May be equal to the sum of

<Combination example>
Each configuration according to the first to third embodiments can be arbitrarily combined. Therefore, the organic EL display device 1 obtained by arbitrarily combining the configurations according to the first to third embodiments is also included in the technical scope of the present disclosure.

[Embodiment 4]
In the present embodiment, differences from the first embodiment will be described. Components having the same functions as the components described in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, the organic EL display device 1 will be described as an example of the display device.

<Schematic Configuration of Organic EL Display Device 1>
In the organic EL display device 1 according to the present embodiment, the blue fluorescent light-emitting material in the blue fluorescent light-emitting material containing layer 34FB is changed from a triplet exciton to a singlet by a triplet-triplet annihilation (TTA) phenomenon. In addition to containing a blue delayed fluorescent light-emitting material (blue TTA material, delayed fluorescent light-emitting material) that generates a term exciton, the thickness of the blue fluorescent light-emitting material-containing layer 34FB is determined by the energy transfer (Dexter transition) by the Dexter mechanism (electron exchange interaction). ) Is the same as the organic EL display device 1 according to the first embodiment except that it is within the range in which ()) occurs.

The blue delayed fluorescent material emits light by re-exciting from the T ₁ level to the S ₁ level in cooperation with the host material or alone by causing a TTA phenomenon by collisional fusion of triplet excitons. I do.

Examples of the blue delayed fluorescent light emitting material include aromatic dimethylidin compounds such as 4,4'-bis (2,2'-diphenylvinyl) -biphenyl (DPVBi), distyrylamine derivatives such as distyryldiamine-based compounds, and pyrene. Derivatives, fluoranthene derivatives, perylene and perylene derivatives, anthracene derivatives, benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, chrysene derivatives, phenanthrene derivatives, distyrylbenzene derivatives and the like.

In the case where this manner blue fluorescent material comprises a blue delayed fluorescence material, T ₁ level of the cyan phosphorescent material in cyan phosphorescent material containing layer 34PC is, T ₁ level of the blue delayed fluorescence material Higher than that.

Dexter transition occurs only between adjacent molecules. Therefore, when the layer thickness of the blue fluorescent light emitting material containing layer 34FB is large, the luminous efficiency may be reduced. Therefore, when utilizing the Dexter transition in this way, it is desirable that the layer thickness of the blue fluorescent light emitting material containing layer 34FB be 5 nm or less. In order to efficiently generate TTA in the blue fluorescent light emitting material containing layer 34FB, the thickness of the blue fluorescent light emitting material containing layer 34FB is preferably 2 nm or less, more preferably 1 nm or less.

<Light Emitting Method of Organic EL Display Device 1>
FIG. 15 is a diagram illustrating a light emitting mechanism in the blue pixel 3B of the organic EL display device 1 according to the fourth embodiment.

As shown in FIG. 15, also in the present embodiment, the holes (h ⁺ ) injected from the anode 21 into the organic EL layer 22 and the electrons (e ⁻ ) injected from the cathode 23 into the organic EL layer 22 are: In the blue pixel 3B, the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB are recombined with each other to generate excitons.

Also in this embodiment, the probability of exciton in the blue fluorescent material-containing layer 34FB is generated as the singlet excited state (S ₁ state) is 25%, it is generated as a triplet excited state (T ₁ state) Probability is 75%. Also, the probability of excitons in cyan phosphorescent material containing layer 34PC is produced as a triplet excited state (T ₁ state) is theoretically 100%.

Some of the triplet excitons generated in the cyan phosphorescent material-containing layer 34PC emit light in the cyan wavelength region (second wavelength region) when returning to the ground state (S ₀ ). The remaining part of the triplet excitons generated in the cyan phosphorescent material containing layer 34PC is a blue fluorescent material energy level of the lowest triplet excited state of the containing layer 34FB (T ₁ level position), Dexter transition (TTET: Triplet-Triplet Energy Transfer).

And thus excitons from T ₁ level position of cyan phosphorescent material containing layer 34PC was Dexter transition to T ₁ level position of the blue fluorescent material-containing layer 34FB undergoes a TTA, containing cyan phosphorescent material It is up-converted to _{S 1} level of the blue fluorescent material-containing layer 34FB having a higher energy level than the _{T 1} level of the _{S 1} level position and a blue fluorescent material-containing layer 34FB layer 34PC.

As a result, the light emitted from the blue pixel 3B includes (i) cyan phosphorescence generated when the triplet exciton generated in the cyan phosphorescent material-containing layer 34PC returns to the ground state (S ₀ ); (Ii) blue fluorescence generated when the singlet exciton generated in the blue fluorescent material-containing layer 34FB returns to the ground state (S ₀ ); (iii) triple light generated in the cyan phosphorescent material-containing layer 34PC A part of the energy of the term exciton is transferred to the triplet exciton generated in the blue fluorescent material-containing layer 34FB by the Dexter mechanism, and the triplet exciton generated in the blue fluorescent material-containing layer 34FB by TTA. Blue fluorescence generated when the singlet exciton, which is generated by up-conversion from the exciton to the singlet exciton, returns to the ground state.

As described above, the light emitted from the blue pixel 3B is transferred from the blue fluorescent light emitting material containing layer 34FB by the energy transfer (Dexter transition) of the triplet exciton from the cyan phosphorescent material containing layer 34PC and the upconversion via TTA. By further including the emitted fluorescent light, the internal quantum efficiency of the blue fluorescent light emitting material containing layer 34FB can theoretically be increased to 40%. For this reason, according to the present embodiment, the luminous efficiency of the blue pixel 3B can be further improved.

Incidentally, if the blue fluorescent material-containing layer 34FB comprises a host material, T ₁ level of the host material may be smaller than the T ₁ level of the blue fluorescent material. Thereby, the triplet excitons are concentrated on the host material, and the density of the triplet excitons is increased. As a result, triplet excitons collide efficiently, and singlet excitons are efficiently generated.

Further, S ₁ level of the blue fluorescent material is preferably smaller than S ₁ level of the host material. Thereby, the singlet exciton of the host material generated by TTA transfers energy to the blue fluorescent light emitting material, and the blue fluorescent light emitting material emits fluorescent light.

[Embodiment 5]
In this embodiment, differences from

Embodiments

1 and 4 will be described. Components having the same functions as the components described in the first or fourth embodiment are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, the organic EL display device 1 will be described as an example of the display device.

<Schematic Configuration of Organic EL Display>
FIG. 16 is a cross-sectional view illustrating a schematic configuration of a main part of the organic EL display device 1 according to the fifth embodiment.

As shown in FIG. 16, in the organic EL display device 1 according to the present embodiment, in the blue pixel 3B, of the cyan phosphorescent material-containing layer 34PC and the blue fluorescent material-containing layer 34FB, the blue The organic EL display according to

Embodiment

1 or 4, except that a hole blocking layer 37 is provided between the fluorescent light emitting material containing layer 34FB and the cathode 23 and adjacent to the blue fluorescent light emitting material containing layer 34FB. It is the same as the device 1.

The organic EL layer 22 of the organic EL display device 1 according to this embodiment includes, from the anode 21 side, a hole injection layer 31, a hole transport layer 32, a light emitting layer unit 33 including a plurality of light emitting material containing layers 34, and holes. It has a configuration in which a block layer 37, an electron transport layer 35, and an electron injection layer 36 are stacked in this order.

In the present embodiment, the hole blocking layer 37 is provided only in the blue pixel 3B among the plurality of pixels 3. As described in the first embodiment, the cyan phosphorescent material-containing layer 34PC functions as a hole blocking layer for the green phosphorescent material-containing layer 34PG and the red phosphorescent material-containing layer 34PR. Therefore, it is not necessary to separately provide the hole blocking layer 37 for the green pixel 3G and the red pixel 3R. In the present embodiment, since the cyan pixel 3C does not include the blue fluorescent light emitting material containing layer 34FB, it is not necessary to separately provide the hole blocking layer 37 in the cyan pixel 3C.

The hole blocking layer 37 is provided on the cathode 23 side of the blue fluorescent light emitting material containing layer 34FB. The hole blocking layer 37 is a layer adjacent to the hole blocking layer 37 among the cyan phosphorescent material-containing layer 34PC and the blue fluorescent light-emitting material-containing layer 34FB (the blue fluorescent light-emitting material-containing layer 34FB in the example shown in FIG. 16). May be formed of a material having a HOMO level deeper than the materials (host material and light-emitting material) contained in, and the thickness thereof is not particularly limited.

電子 As the material of the hole blocking layer 37, for example, an electron transporting material can be used. As the electric transporting material, for example, the materials exemplified above can be used.

<Manufacturing method of organic EL display device 1>
FIG. 17 is a plan view illustrating a hole blocking layer forming step in the manufacturing process of the organic EL display device 1 according to the fifth embodiment.

In the manufacturing process of the organic EL display device 1 according to the present embodiment, the organic EL element manufacturing process forms the hole blocking layer 37 provided on the blue pixel 3B on the side of the cathode 23 in the blue fluorescent light emitting material containing layer 34FB (lamination). This is the same as the manufacturing process of the organic EL display device 1 according to the first embodiment except that a hole blocking layer forming process is performed.

When the organic EL display device 1 shown in FIG. 16 is manufactured as the organic EL display device 1 according to the present embodiment, the hole blocking layer forming step shown in FIG. 17 includes the blue fluorescent light emitting material containing layer 34FB and the hole blocking layer 37. Are successively performed in the blue fluorescent light emitting material containing layer forming step shown in FIG.

In the hole block layer forming step shown in FIG. 17, the stripe-shaped islands are formed on the blue fluorescent light emitting material-containing layer 34FB by separate deposition using a deposition mask 200HB provided with a mask opening 201HB corresponding to the blue pixel 3B. A hole-blocking layer 37 is formed.

Note that, similarly to FIGS. 7A to 7D, FIG. 17 shows an example in which the evaporation mask 200HB is an evaporation mask for mask fixed evaporation. However, the present embodiment is not limited to this, and the deposition mask 200HB may be a deposition mask for scan deposition having a mask opening corresponding to a part of the hole blocking layer 37 to be formed. Good.

Then, the organic EL display device 1 shown in FIG. 16 can be manufactured by performing the electron transport layer forming step, the electron injection layer forming step, the cathode forming step, and the sealing step in the same manner as in the first embodiment.

According to the present embodiment, as described above, in the blue pixel 3 </ b> B, between the blue fluorescent light emitting material containing layer 34 FB located on the cathode 23 side and the cathode 23, the positive electrode is disposed adjacent to the blue fluorescent light emitting material containing layer 34 FB. By providing the hole blocking layer 37, it is possible to prevent holes from leaking from the blue fluorescent light emitting material containing layer 34FB in the blue pixel 3B.

Therefore, according to the present embodiment, it is possible to suppress a decrease in luminous efficiency due to hole leakage in each pixel 3.

The present disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present disclosure. Further, new technical features can be formed by combining the technical means disclosed in each embodiment.

The display device according to the present disclosure is not limited to the organic EL display device 1 described above, and may be realized as various display devices.

[Summary]
The display device according to the first aspect of the present invention includes a plurality of pixels including a first pixel that emits blue light and a second pixel that emits light having a peak wavelength longer than the blue light. A display device comprising, for each pixel, an anode, a cathode, and an organic layer including a light-emitting layer formed between the anode and the cathode, wherein the first pixel includes the light-emitting layer A first phosphorescent material-containing layer including a first phosphorescent material that emits cyan phosphorescent light; and a shorter wavelength than the cyan phosphorescent light provided on the cathode side in the first phosphorescent material-containing layer. A fluorescent light-emitting material-containing layer containing a fluorescent light-emitting material that emits blue fluorescence having a peak wavelength of, and the second pixel has the first phosphorescent light-emitting material-containing layer as the light-emitting layer, The first phosphorescent material-containing layer is common to the plurality of pixels. A common layer provided in the first pixel, wherein the first phosphorescent material-containing layer and the fluorescent light-emitting material-containing layer emit light, and in the second pixel, the first phosphorescent material-containing layer emits light. Configuration.

In the display device according to an aspect 2 of the present invention, in the aspect 1, the second pixel further includes the fluorescent light emitting material-containing layer as the light emitting layer, and the common layer includes the fluorescent light emitting material. In the second pixel, the first phosphorescent material-containing layer and the fluorescent light-emitting material-containing layer may emit light.

The display device according to aspect 3 of the present invention is the display device according to aspect 2, wherein the organic layer is provided between the light-emitting layer and the anode, the first pixel and the first pixel being individually provided for the second pixel and the second pixel, respectively. It may have a hole transport layer and a second hole transport layer, and at least one of the thickness and the material of the first hole transport layer and the second hole transport layer may be different from each other.

In the display device according to the fourth aspect of the present invention, in the third aspect, the thickness of the second hole transport layer may be larger than the thickness of the first hole transport layer.

In the display device according to a fifth aspect of the present invention, in the fourth aspect, the difference between the film thickness of the second hole transport layer and the film thickness of the first hole transport layer is 5 to 25 nm. It may be configured.

The display device according to an aspect 6 of the present invention, in any one of the aspects 3 to 5, wherein the material of the second hole transport layer has a higher ionization potential energy than the material of the first hole transport layer. It may be configured.

The display device according to aspect 7 of the present invention, in any one of aspects 3 to 6, wherein the material of the first hole transport layer is N, N′-di (naphthalen-1-yl) -N, N '-Diphenyl-benzidine (α-NPD), and the material of the second hole transport layer is 4,4', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenyl The structure may be amine (MTDATA) or 1,3-bis (carbazol-9-yl) benzene (mCP).

A display device according to an eighth aspect of the present invention, in any one of the first to seventh aspects, may be configured such that at least one of the thickness and the material of the anode is different between the first pixel and the second pixel. .

In the display device according to an aspect 9 of the present invention, in the aspect 8, the thickness of the anode forming the second pixel may be larger than the thickness of the anode forming the first pixel. .

The display according to an aspect 10 of the present invention, in the aspect 9, the difference between the film thickness of the anode forming the second pixel and the film thickness of the anode forming the first pixel is 5 to 5. The configuration may be 10 nm.

The display device according to aspect 11 of the present invention, in any one of aspects 8 to 10, wherein the material of the anode forming the first pixel is ITO, and the material of the anode forming the second pixel is May be ITO and IZO.

The display device according to aspect 12 of the present invention, according to any one of aspects 1 to 11, wherein the triplet exciton generated in the first phosphorescent material-containing layer returns to the ground state in the first pixel. And the fluorescence generated when the singlet exciton generated in the fluorescent light emitting material-containing layer returns to the ground state is emitted, and the second pixel contains the first phosphorescent light emitting material. Phosphorescence generated when the triplet exciton generated in the layer returns to the ground state may be emitted.

The display device according to aspect 13 of the present invention is the display device according to aspect 12, wherein the fluorescent material includes a delayed fluorescent material that generates a singlet exciton from a triplet exciton by a triplet-triplet annihilation phenomenon; The triplet excitation level of the first phosphorescent material is higher than the triplet excitation level of the delayed fluorescent material, and the thickness of the fluorescent material-containing layer is within a range where energy transfer by the Dexter mechanism occurs. In the light emitted from the first pixel, a part of the energy of the triplet exciton generated in the first phosphorescent material-containing layer is generated in the fluorescent light-emitting material-containing layer by the Dexter mechanism. It moves to a triplet exciton and is converted by the triplet-triplet annihilation phenomenon from the triplet exciton generated in the fluorescent material-containing layer to the singlet exciton, thereby producing a singlet exciton. Fluorescence may further comprise configure occurring when singlet excitons return to their ground state.

The display device according to an aspect 14 of the present invention is the display device according to any one of the aspects 1 to 13, wherein the plurality of pixels emit light having a longer peak wavelength than light emitted from the second pixel. The pixel further includes three pixels, wherein the third pixel includes, as the light-emitting layer, the common layer having the first phosphorescent material-containing layer and the fluorescent light-emitting material-containing layer, and a peak having a longer wavelength than the cyan phosphorescence. A second phosphorescent material-containing layer containing a second phosphorescent material that emits phosphorescence having a wavelength, wherein the second phosphorescent material-containing layer emits light in the third pixel.

In the display device according to an aspect 15 of the present invention, in the aspect 14, the second phosphorescent material-containing layer is provided on the anode side in the first phosphorescent material-containing layer constituting the third pixel. Configuration.

The display device according to Aspect 16 of the present invention, in the Aspect 14 or 15, wherein in the third pixel, the phosphorescence generated when the triplet exciton generated in the second phosphorescent material-containing layer returns to the ground state. May be emitted.

The display device according to aspect 17 of the present invention, in any one of aspects 14 to 16, wherein the first phosphorescent material has a HOMO level deeper than the second phosphorescent material. Good.

The display device according to an aspect 18 of the present invention, in the aspect 17, the triplet excitation level of the first phosphorescent material may be higher than the triplet excitation level of the second phosphorescent material. .

The display device according to aspect 19 of the present invention, according to any one of aspects 16 to 18, wherein the fluorescent material-containing layer includes a material having a HOMO level shallower than the first phosphorescent material-containing layer. And a material having a LUMO level shallower than the first phosphorescent material-containing layer.

The display according to an aspect 20 of the present invention is the display device according to any one of the aspects 16 to 19, wherein the first phosphorescent material-containing layer comprises a hole-transporting material, or a hole-transporting material and an electron-transporting material. A bipolar transport material containing an organic material, and the fluorescent light emitting material-containing layer may include an electron transport material.

The display device according to Aspect 21 of the present invention is the display device according to Aspect 19 or 20, wherein the organic layer in the first pixel is provided between the fluorescent-emitting material-containing layer and the cathode, in the fluorescent-luminescent material-containing layer. A configuration in which a hole blocking layer is provided adjacently may be employed.

A display device according to an aspect 22 of the present invention is the display device according to any one of the aspects 1 to 21, wherein one of the anode and the cathode has a reflective layer, and the other electrode has a transflective layer. The distance between the reflective layer and the semi-transmissive reflective layer may be an optical path length at which the peak wavelength of the color light emitted from each pixel resonates.

The method for manufacturing a display device according to aspect 23 of the present invention includes a plurality of pixels including: a first pixel that emits blue light; and a second pixel that emits light having a peak wavelength longer than the blue light. Comprising a pixel, an anode, a cathode, and an organic layer including a light-emitting layer formed between the anode and the cathode, wherein the first pixel includes: A first phosphorescent material-containing layer that includes a first phosphorescent material that emits cyan phosphorescent light; and a first phosphorescent material-containing layer that is provided on the cathode side of the first phosphorescent material-containing layer. A fluorescent light-emitting material-containing layer containing a fluorescent light-emitting material that emits blue fluorescence having a short wavelength peak wavelength, and wherein the second pixel includes the first phosphorescent light-emitting material-containing layer as the light-emitting layer. Wherein said first phosphorescent material-containing layer comprises A common layer provided in common to the pixels, wherein the first pixel emits light from the first phosphorescent material-containing layer and the fluorescent light-emitting material-containing layer, and the second pixel emits the first phosphorescent light from the first pixel. A method for manufacturing a display device in which a material-containing layer emits light, including an anode forming step of forming the anode, an organic layer forming step of forming the organic layer, and a cathode forming step of forming the cathode. The organic layer forming step includes a common layer forming step of forming the common layer using a deposition mask having a mask opening common to the plurality of pixels, and a vapor deposition in which a mask opening corresponding to the first pixel is provided. Forming a fluorescent light emitting material-containing layer in the first pixel using a mask; and forming the first phosphorescent light emitting material-containing layer in the common layer forming step. First phosphorescence The method comprising material-containing layer forming step.

In the method for manufacturing a display device according to Aspect 24 of the present invention, in the Aspect 23, in the organic layer forming step, the first hole transport layer and the second hole transport layer in which at least one of a material and a film thickness are different from each other. A hole transport layer forming step of forming a layer, wherein the hole transport layer forming step includes applying a first hole to the first pixel using a deposition mask having a mask opening corresponding to the first pixel. A first hole transport layer forming step of forming a hole transport layer, and a step of forming the second hole transport layer in the second pixel using a deposition mask having a mask opening corresponding to the second pixel. And (2) a hole transport layer forming step.

In the method for manufacturing a display device according to aspect 25 of the present invention, in the

aspect

23 or 24, in the anode forming step, the anode is formed in the first pixel, and the first pixel is formed in the second pixel. A method may be used in which the anode is different from the anode forming the pixel in at least one of a material and a film thickness.

The method for manufacturing a display device according to Aspect 26 of the present invention is the method according to any one of Aspects 23 to 25, wherein the first phosphorescent material-containing layer forming step and the fluorescent light-emitting material-containing layer forming step are the first A method may be adopted in which the phosphorescent material-containing layer and the fluorescent light-emitting material-containing layer are continuously stacked so as to be adjacently stacked.

In the method for manufacturing a display device according to Aspect 27 of the present invention, in any one of Aspects 23 to 26, the organic layer forming step is provided on the first pixel on the cathode side in the fluorescent material-containing layer. A hole blocking layer forming step of forming a hole blocking layer to be formed, wherein the hole blocking layer forming step is performed between the fluorescent light emitting material containing layer forming step and the cathode forming step, and the fluorescent light emitting layer is formed. A method may be adopted in which the material-containing layer forming step and the hole blocking layer forming step are performed continuously so that the fluorescent light emitting material containing layer and the hole blocking layer are stacked adjacent to each other.

A light emitting method of a display device according to an aspect 28 of the present invention includes a plurality of pixels including a first pixel that emits blue light and a second pixel that emits light having a peak wavelength longer than the blue light. Comprising a pixel, an anode, a cathode, and an organic layer including a light-emitting layer formed between the anode and the cathode, wherein the first pixel includes: A first phosphorescent material-containing layer that includes a first phosphorescent material that emits cyan phosphorescent light; and a first phosphorescent material-containing layer that is provided on the cathode side of the first phosphorescent material-containing layer. A fluorescent light-emitting material-containing layer containing a fluorescent light-emitting material that emits blue fluorescence having a short wavelength peak wavelength, and wherein the second pixel includes the first phosphorescent light-emitting material-containing layer as the light-emitting layer. Wherein said first phosphorescent material-containing layer comprises A common layer provided in common to the pixels, wherein the first pixel emits light from the first phosphorescent material-containing layer and the fluorescent light-emitting material-containing layer, and the second pixel emits the first phosphorescent light from the first pixel. A light emitting method for a display device in which a material-containing layer emits light, wherein, in the first pixel, a triplet exciton is generated in the first phosphorescent material-containing layer, and a singlet exciton is generated in the fluorescent light-emitting material-containing layer. And the light generated when the triplet exciton generated in the first phosphorescent material-containing layer returns to the ground state and the singlet exciton generated in the fluorescent light-emitting material-containing layer return to the ground state The second pixel generates a triplet exciton in the first phosphorescent material-containing layer, and the triplet generated in the first phosphorescent material-containing layer in the second pixel. Emits light when excitons return to the ground state It is a method.

In the light emitting method for a display device according to aspect 29 of the present invention, in the aspect 28, in the first pixel, a part of the energy of the triplet exciton generated in the first phosphorescent material-containing layer is converted to Dexter. By the mechanism, the singlet exciton is moved from the triplet exciton generated in the fluorescent light emitting material-containing layer to the triplet exciton generated in the fluorescent light emitting material-containing layer by a triplet-triplet annihilation phenomenon. A method may be used in which the singlet exciton generated by up-conversion to a state of returning to the ground state further emits fluorescence.

1 Organic EL display device (display device)
3B blue pixel (first pixel)
3C cyan pixel (second pixel)
3G green pixel (third pixel)
3R red pixel (third pixel)
20B Blue organic EL element 20C Cyan organic EL element 20G Green organic EL element 20R Red organic EL element 21 Anode 21a Reflection electrode (reflection layer)
21b Translucent electrode 21c Translucent electrode 22 Organic EL layer (organic layer)
Reference Signs 23 cathode 24 edge cover 32 hole transport layer 32B hole transport layer (first hole transport layer)
32C hole transport layer (second hole transport layer)
33 light emitting layer unit 34FB Blue fluorescent light emitting material containing layer (fluorescent light emitting material containing layer)
34PC Cyan phosphorescent material-containing layer (first phosphorescent material-containing layer)
34PG Green phosphorescent material-containing layer (second phosphorescent material-containing layer)
34PR Red phosphorescent material-containing layer (second phosphorescent material-containing layer)
37 Hole blocking layer 200B, 200B2, 200C, 200G, 200R, 210B, 210C Evaporation mask 201B, 201B2, 201C, 201G, 201R, 211B, 211C Mask opening

Claims

A plurality of pixels including a first pixel that emits blue light and a second pixel that emits light having a peak wavelength longer than the blue light, wherein each pixel has an anode, a cathode, A display device provided with an organic layer including a light-emitting layer, formed between the anode and the cathode,
The first pixel is provided as a light-emitting layer, a first phosphorescent material-containing layer including a first phosphorescent material that emits cyan phosphorescence, and a cathode side of the first phosphorescent material-containing layer, A fluorescent light-emitting material-containing layer containing a fluorescent light-emitting material that emits blue fluorescence having a shorter peak wavelength than the cyan phosphorescence,
The second pixel has the first phosphorescent material-containing layer as the light-emitting layer,
The first phosphorescent material-containing layer is a common layer provided in common to the plurality of pixels,
In the first pixel, the first phosphorescent material-containing layer and the fluorescent material-containing layer emit light, and in the second pixel, the first phosphorescent material-containing layer emits light. .
The second pixel further includes the fluorescent light-emitting material-containing layer as the light-emitting layer,
The common layer further includes the fluorescent light emitting material-containing layer,
The display device according to claim 1, wherein, in the second pixel, the first phosphorescent material-containing layer and the fluorescent light-emitting material-containing layer each emit light.
The organic layer has a first hole transport layer and a second hole transport layer separately provided for the first pixel and the second pixel between the light emitting layer and the anode,
The display device according to claim 2, wherein at least one of a film thickness and a material of the first hole transport layer and the second hole transport layer are different from each other.
4. The display device according to claim 3, wherein the thickness of the second hole transport layer is larger than the thickness of the first hole transport layer.
The display device according to claim 4, wherein the difference between the thickness of the second hole transport layer and the thickness of the first hole transport layer is 5 to 25 nm.
The display device according to any one of claims 3 to 5, wherein the material of the second hole transport layer has a higher ionization potential energy than the material of the first hole transport layer.
The material of the first hole transport layer is N, N′-di (naphthalen-1-yl) -N, N′-diphenyl-benzidine (α-NPD),
The material of the second hole transport layer is 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) or 1,3-bis ( The display device according to any one of claims 3 to 6, wherein the display device is (carbazol-9-yl) benzene (mCP).
8. The display device according to claim 1, wherein at least one of the thickness and the material of the anode is different between the first pixel and the second pixel.
The display device according to claim 8, wherein the thickness of the anode forming the second pixel is larger than the thickness of the anode forming the first pixel.
The display device according to claim 9, wherein the difference between the thickness of the anode forming the second pixel and the thickness of the anode forming the first pixel is 5 to 10 nm.
The material of the anode constituting the first pixel is ITO,
The display device according to any one of claims 8 to 10, wherein a material of the anode forming the second pixel is ITO or IZO.
* Part of claim 2 of 17J00658 In the first pixel, the phosphorescence generated when the triplet exciton generated in the first phosphorescent material-containing layer returns to the ground state, and the phosphorescent light generated in the fluorescent light-emitting material-containing layer. And the fluorescence generated when the singlet exciton returned to the ground state is emitted,
12. The device according to claim 1, wherein the second pixel emits phosphorescence generated when a triplet exciton generated in the first phosphorescent material-containing layer returns to a ground state. A display device according to claim 1.
The fluorescent material includes a delayed fluorescent material that generates a singlet exciton from a triplet exciton by a triplet-triplet annihilation phenomenon;
The triplet excitation level of the first phosphorescent material is higher than the triplet excitation level of the delayed fluorescent light-emitting material,
The thickness of the fluorescent light-emitting material-containing layer is within a range in which energy transfer by the Dexter mechanism occurs,
In the light emitted from the first pixel, a part of the energy of the triplet exciton generated in the first phosphorescent material-containing layer is converted into the triplet exciton generated in the fluorescent light-emitting material-containing layer by the Dexter mechanism. Singlet exciton that is generated by up-conversion from the triplet exciton generated in the layer containing the fluorescent material to the singlet exciton due to the triplet-triplet annihilation phenomenon. 13. The display device according to claim 12, further comprising fluorescence generated when the light source returns to the ground state.
The plurality of pixels further include a third pixel that emits light having a longer peak wavelength than the light emitted by the second pixel,
The third pixel emits, as the light-emitting layer, the common layer having the first phosphorescent material-containing layer and the fluorescent light-emitting material-containing layer, and phosphorescence having a peak wavelength longer than the cyan phosphorescence. A second phosphorescent material-containing layer containing a second phosphorescent material,
14. The display device according to claim 1, wherein in the third pixel, the second phosphorescent material-containing layer emits light.
The display device according to claim 14, wherein the second phosphorescent material-containing layer is provided on the anode side in the first phosphorescent material-containing layer constituting the third pixel.
* A part of claim 2 of 17J00658 The third pixel emits phosphorescence generated when triplet excitons generated in the second phosphorescent material-containing layer return to the ground state. Item 16. The display device according to Item 14 or 15.
The display device according to any one of claims 14 to 16, wherein the first phosphorescent material has a HOMO level deeper than the second phosphorescent material.
* Claim 5 of 17J00658
The display device according to claim 17, wherein a triplet excitation level of the first phosphorescent material is higher than a triplet excitation level of the second phosphorescent material.
The fluorescent light emitting material containing layer includes a material having a HOMO level shallower than the first phosphorescent light emitting material containing layer, and includes a material having a LUMO level shallower than the first phosphorescent light emitting material containing layer. The display device according to any one of claims 16 to 18, characterized in that:
The first phosphorescent material-containing layer includes a hole transporting material, or a bipolar transporting material including a hole transporting material and an electron transporting material,
The display device according to any one of claims 16 to 19, wherein the fluorescent light emitting material containing layer contains an electron transporting material.
The organic layer in the first pixel, further comprising a hole blocking layer between the fluorescent material-containing layer and the cathode, adjacent to the fluorescent material-containing layer. 21. The display device according to 19 or 20.
One of the anode and the cathode has a reflective layer, the other electrode has a transflective reflective layer,
The distance between the reflective layer and the semi-transmissive reflective layer is an optical path length at which a peak wavelength of light of a color emitted from each pixel resonates. The display device according to claim 1.
A plurality of pixels including a first pixel that emits blue light and a second pixel that emits light having a peak wavelength longer than the blue light, wherein each pixel has an anode, a cathode, A display device provided with an organic layer including a light emitting layer formed between the anode and the cathode, wherein the first pixel emits cyan phosphorescent light as the light emitting layer. A first phosphorescent material-containing layer containing a phosphorescent material, and a blue phosphor having a peak wavelength shorter than that of the cyan phosphorescent light, which is provided on the cathode side of the first phosphorescent material-containing layer. A fluorescent light emitting material-containing layer containing a fluorescent light emitting material, wherein the second pixel has the first phosphorescent light emitting material containing layer as the light emitting layer, and wherein the first phosphorescent light emitting material containing layer is A common layer provided in common to a plurality of pixels; The pixel, the first phosphorescent material containing layer and the fluorescent material-containing layer emits light, respectively, in the second pixel, the first phosphorescent material containing layer is a method of manufacturing a display device that emits light,
An anode forming step of forming the anode,
An organic layer forming step of forming the organic layer,
A cathode forming step of forming the cathode,
The organic layer forming step,
Using a deposition mask having a mask opening common to the plurality of pixels, a common layer forming step of forming the common layer,
A fluorescent light emitting material-containing layer forming step of forming the fluorescent light emitting material-containing layer on the first pixel using an evaporation mask provided with a mask opening corresponding to the first pixel;
The method of manufacturing a display device, wherein the common layer forming step includes a first phosphorescent material-containing layer forming step of forming the first phosphorescent material-containing layer.
The organic layer forming step further includes a hole transport layer forming step of forming a first hole transport layer and a second hole transport layer having at least one of a material and a film thickness different from each other,
The hole transport layer forming step,
A first hole transport layer forming step of forming the first hole transport layer on the first pixel using a deposition mask having a mask opening corresponding to the first pixel;
A second hole transport layer forming step of forming the second hole transport layer in the second pixel using a deposition mask having a mask opening corresponding to the second pixel. A method for manufacturing a display device according to claim 23.
In the anode forming step, the anode is formed on the first pixel, and the anode having at least one of a material and a film thickness different from that of the anode constituting the first pixel is formed on the second pixel. The method for manufacturing a display device according to claim 23, wherein the method comprises:
The first phosphorescent material-containing layer forming step and the fluorescent light-emitting material-containing layer forming step are continuously performed so that the first phosphorescent light-emitting material-containing layer and the fluorescent light-emitting material-containing layer are stacked adjacent to each other. The method for manufacturing a display device according to any one of claims 23 to 25, wherein the method is performed.
The organic layer forming step includes, in the first pixel, a hole blocking layer forming step of forming a hole blocking layer provided on the cathode side of the fluorescent light emitting material-containing layer,
The hole blocking layer forming step is performed between the fluorescent light emitting material containing layer forming step and the cathode forming step,
The fluorescent light emitting material-containing layer forming step and the hole blocking layer forming step are performed continuously so that the fluorescent light emitting material containing layer and the hole blocking layer are stacked adjacent to each other. The method for manufacturing a display device according to any one of claims 23 to 26.
A plurality of pixels including a first pixel that emits blue light and a second pixel that emits light having a peak wavelength longer than the blue light, wherein each pixel has an anode, a cathode, A display device provided with an organic layer including a light emitting layer formed between the anode and the cathode, wherein the first pixel emits cyan phosphorescence as the light emitting layer. A first phosphorescent material-containing layer containing a phosphorescent material, and a blue phosphor having a shorter peak wavelength than the cyan phosphorescent light, which is provided on the cathode side of the first phosphorescent material-containing layer. A fluorescent light emitting material-containing layer containing a fluorescent light emitting material, wherein the second pixel has the first phosphorescent light emitting material containing layer as the light emitting layer, and wherein the first phosphorescent light emitting material containing layer is A common layer provided in common to a plurality of pixels; The pixel, the first phosphorescent material containing layer and the fluorescent material-containing layer emits light, respectively, in the second pixel, the first phosphorescent material containing layer is a light-emitting method of a display device that emits light,
In the first pixel, a triplet exciton is generated in the first phosphorescent material-containing layer and a singlet exciton is generated in the fluorescent light-emitting material-containing layer, and the singlet exciton is generated in the first phosphorescent material-containing layer. Light generated when the triplet exciton returned to the ground state, and light generated when the singlet exciton generated in the fluorescent light emitting material-containing layer returns to the ground state, emits light including:
In the second pixel, a triplet exciton is generated in the first phosphorescent material-containing layer, and light generated when the triplet exciton generated in the first phosphorescent material-containing layer returns to the ground state is emitted. A light emitting method for a display device.
In the first pixel, part of the energy of the triplet exciton generated in the first phosphorescent material-containing layer is transferred to the triplet exciton generated in the fluorescent light-emitting material-containing layer by the Dexter mechanism. Due to the triplet-triplet annihilation phenomenon, when the singlet exciton generated by up-conversion from the triplet exciton generated in the fluorescent material-containing layer to the singlet exciton returns to the ground state, The method according to claim 28, wherein the generated fluorescence is further emitted.