WO2011145358A1 - Substrat de luminophore, élément électroluminescent et dispositif d'affichage - Google Patents

Substrat de luminophore, élément électroluminescent et dispositif d'affichage Download PDF

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WO2011145358A1
WO2011145358A1 PCT/JP2011/051211 JP2011051211W WO2011145358A1 WO 2011145358 A1 WO2011145358 A1 WO 2011145358A1 JP 2011051211 W JP2011051211 W JP 2011051211W WO 2011145358 A1 WO2011145358 A1 WO 2011145358A1
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light
layer
pair
color conversion
conversion layer
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PCT/JP2011/051211
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Japanese (ja)
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秀謙 尾方
勇毅 小林
健 岡本
誠 山田
悦昌 藤田
克己 近藤
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シャープ株式会社
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/30—Devices specially adapted for multicolour light emission
    • H10K59/38—Devices specially adapted for multicolour light emission comprising colour filters or colour changing media [CCM]
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H10K50/125—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers specially adapted for multicolour light emission, e.g. for emitting white light
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/875—Arrangements for extracting light from the devices
    • H10K59/876—Arrangements for extracting light from the devices comprising a resonant cavity structure, e.g. Bragg reflector pair

Definitions

  • the present invention relates to a phosphor substrate, a light emitting element, and a display device using the same.
  • Non-self-luminous liquid crystal displays LCD
  • self-luminous plasma displays PDP
  • inorganic electroluminescent (inorganic EL) displays organic electroluminescent (organic EL) displays, etc.
  • flat panel displays It has been.
  • the organic EL display has attracted particular attention in terms of self-luminescence.
  • the above-described conventional methods have problems such as mask processing accuracy, mask alignment accuracy, and mask enlargement, and in particular, mask enlargement is a major issue. That is, in the field of large displays typified by TVs, the substrate sizes are increasing from G6 to G8, G10, and in order to perform the above method, the substrate size is increased to be equal to or larger than such a substrate size. It is necessary to prepare and process a mask. However, since the mask is made of a very thin metal (general film thickness: 50 to 100 nm), it is very difficult to manufacture and process a large-sized mask.
  • an evaporation source is arranged on the lower side of the substrate, and an organic layer is formed by evaporating an organic material from the bottom upward.
  • an organic layer is formed by evaporating an organic material from the bottom upward.
  • the mask becomes unusable due to deterioration after a specific number of times of use. Therefore, when the mask becomes large, it leads to a problem of cost increase when manufacturing the display.
  • the cost problem is regarded as the biggest problem.
  • an organic EL element having a microcavity (optical microresonator) structure has been proposed (see, for example, Patent Documents 2, 3, and 4).
  • an organic EL element to which a microresonance structure is applied light generated from the light emitting layer is repeatedly reflected between the reflective electrode and the semi-reflective electrode, so that only light having the same wavelength is emitted from the semi-reflective electrode side.
  • strength of a specific wavelength can be strengthened and directivity can be given to emitted light (refer FIG. 5).
  • Patent Documents 2 to 4 disclose a technique in which an organic EL element having a microresonator structure and the above-described color conversion layer are combined.
  • this technology from the viewpoint of luminous efficiency, element lifetime, and the like, blue pixels emit blue light from organic EL elements having a microresonator structure, and green and red pixels emit from the organic EL elements. The blue light emission is converted into fluorescence in each color conversion layer, and the resulting converted light is emitted.
  • Patent Document 5 As a method for solving this problem, a technique disclosed in Patent Document 5 has been proposed.
  • the pair of light reflection layers adjust the microresonator structure in accordance with the wavelength of the converted light of the color conversion layer. For this reason, in each pixel, the microresonator structure can be adjusted according to the wavelength of each color, and the color purity according to the viewing angle can be adjusted between the colors.
  • Patent Document 5 no consideration is given to enhancing excitation light for exciting the color conversion layer, and the efficiency of fluorescence conversion in the color conversion layer is described in Patent Documents 2 to Compared to 4, it is decreasing. That is, according to the technique disclosed in Patent Document 5, the object of improving the light emission efficiency of the organic EL element cannot be sufficiently achieved.
  • the color conversion layer is patterned due to its structure.
  • a wet process such as photolithography cannot be used. That is, the patterning of the color conversion layer requires separate deposition using a shadow mask, so that the simplicity of the manufacturing process by the fluorescence conversion method is lost, and the cost advantage is lost.
  • the present invention has been made to solve the above-described problems, and has as its object to provide a phosphor substrate capable of easily producing a light emitting device with improved luminous efficiency, and a light emitting device with improved luminous efficiency and It is to provide a display device.
  • the phosphor substrate according to the present invention is sandwiched between a pair of light reflecting layers, a pair of light reflecting layers formed on the substrate, and the pair of light reflecting layers.
  • a color conversion layer that absorbs excitation light emitted from an external light source on the side opposite to the substrate with respect to the other light reflection layer and emits converted light of a color different from the color of the excitation light;
  • the optical distance between the pair of light reflecting layers is set to an optical distance constituting a microresonator that enhances the intensity of the converted light emitted from the color conversion layer.
  • the phosphor substrate according to the present invention can be used for manufacturing a light emitting device.
  • a light-emitting element can be easily produced by combining the phosphor substrate according to the present invention with an external light source such as an electroluminescence (EL) element.
  • the color conversion layer absorbs light emitted from an external light source such as an EL portion as excitation light and emits converted light.
  • the converted light has improved light extraction efficiency by a microresonator structure formed by a pair of reflective films.
  • the phosphor substrate according to the present invention can be easily combined with an EL element constituting a microresonator structure.
  • a light emitting device with improved luminous efficiency can be easily produced.
  • a display device using the phosphor substrate according to the present invention even in the case of manufacturing a top emission type display device, in order to pattern the color conversion layer, wet such as photolithography is used. A process can be used. Therefore, a display device can be easily manufactured by using the phosphor substrate according to the present invention. It is also possible to reduce the manufacturing cost.
  • a light-emitting element includes a pair of electrodes, an EL layer that is sandwiched between the pair of electrodes and emits light, and the EL layer with respect to one of the pair of electrodes. Is sandwiched between a pair of light reflecting layers disposed on the opposite side and the pair of light reflecting layers, absorbs light emitted from the EL layer, and emits converted light having a color different from that of the light.
  • An optical distance between the pair of light reflection layers is set to an optical distance constituting a microresonator that enhances the intensity of the converted light emitted from the color conversion layer. It is a feature.
  • the pair of reflective films constitute a microresonator without sandwiching the EL layer therebetween.
  • a pair of electrodes can constitute a microresonator structure for the EL layer.
  • the light extraction efficiency of the converted light emitted from the color conversion layer is improved by the microresonator structure formed by the pair of reflective films.
  • a display device when a display device is manufactured using a light emitting element having the above-described structure, a wet process such as photolithography is used to pattern the color conversion layer even when a top emission type device is manufactured. It is possible to use. Therefore, a display device can be easily manufactured by using the light emitting element according to the present invention. It is also possible to reduce the manufacturing cost.
  • a display device is a display device in which a plurality of light emitting elements including light emitting elements of different colors are arranged in an array, and each of the plurality of light emitting elements includes: It is characterized by comprising any one of the light-emitting elements described above.
  • each pixel in which the light emitting element is arranged light whose light extraction efficiency is improved by the microresonator structure is used. For this reason, according to the display device according to the present invention, it is possible to improve the light emission efficiency in a balanced manner in viewability and light emission intensity of each pixel.
  • the phosphor substrate according to the present invention includes a substrate, a pair of light reflecting layers formed on one of the substrates, and the other light reflecting layer sandwiched between the pair of light reflecting layers and different from the one.
  • a color conversion layer that absorbs excitation light emitted from an external light source on the side opposite to the substrate and emits converted light of a color different from the color of the excitation light.
  • the optical distance between them is set to an optical distance constituting a microresonator that enhances the intensity of the converted light emitted from the color conversion layer. Therefore, by using the phosphor substrate according to the present invention, it is possible to easily manufacture a light emitting element with improved luminous efficiency.
  • the light-emitting element includes a pair of light-reflective electrodes, an EL layer that is sandwiched between the pair of light-reflective electrodes and emits light, and the EL for one of the pair of reflective electrodes.
  • a pair of light reflecting layers arranged on the opposite side of the layer and the pair of light reflecting layers, and absorbs light emitted from the EL layer to generate converted light of a color different from the color of the light.
  • an optical distance between the pair of light reflecting layers is set to an optical distance constituting a microresonator that enhances the intensity of the converted light emitted from the color conversion layer. . For this reason, it is possible to provide a light emitting element with improved luminous efficiency.
  • Embodiment 1 The first embodiment of the present invention will be described with reference to FIGS. 1 and 2 as follows.
  • FIG. 1 is a cross-sectional view illustrating a schematic configuration of the light emitting element 100
  • FIG. 2 is a cross-sectional view illustrating a schematic configuration of the phosphor substrate 50.
  • the light emitting element 100 has a configuration in which an EL element substrate 40 and a phosphor substrate 50 are bonded together with a resin layer 6 therebetween.
  • the EL element substrate 40 includes a substrate 1, a first light reflective electrode 2, an EL layer 3, a second light reflective electrode 4, and an inorganic sealing film 5.
  • the phosphor substrate 50 includes a first light reflection layer 7, a color conversion layer 8, a second light reflection layer 9, and a substrate 10.
  • the structure which consists of the 1st light reflective electrode 2, the EL layer 3, and the 2nd light reflective electrode 4 is called the EL part 11.
  • the light emitted from the EL layer 3 of the EL element substrate 40 is extracted to the phosphor substrate 50 side, and the light converted by the color conversion layer 8 of the phosphor substrate 50 is extracted to the side opposite to the EL element substrate 40 side. That is, in the EL element substrate 40, the EL layer 3 emits light, and in the phosphor substrate 50, the color conversion layer 8 absorbs the light emitted from the EL layer 3, and emits converted light having a wavelength different from that of the light. .
  • Substrate 1, 10 examples include an inorganic material substrate made of glass or quartz, a plastic substrate made of polyethylene terephthalate, polycarbazole, polyimide, or the like, but the present invention is limited to these substrates. It is not a thing.
  • the plastic substrate as the substrates 1 and 10.
  • the substrate 1 has transparency for taking out the converted light from the color conversion layer 8 to the outside.
  • the substrate 10 it is preferable to use a substrate obtained by coating a plastic substrate with an inorganic material from the viewpoint of improving gas barrier properties. It is known that the organic EL deteriorates even with a low amount of moisture, and when the plastic substrate is used as the organic EL substrate, the deterioration of the organic EL due to the permeation of moisture becomes the biggest problem. . If the substrate 10 with improved gas barrier properties is used as described above, this problem can be solved.
  • the first light-reflecting electrode 2 and the second light-reflecting electrode 4 are electrically conductive films that sandwich the EL layer 3, and are reflections for configuring a microresonator that enhances light emitted from the EL layer 3. Have a rate.
  • the reflectance of the first light reflective electrode 2 is preferably 50% or more, more preferably 70% or more, with respect to the light emitted from the EL layer 3.
  • the second light-reflecting electrode 4 is preferably semi-transmissive to the light emitted from the EL layer 3 and has a reflectance of 25% or more.
  • Examples of the configuration of the first light reflective electrode 2 and the second light reflective electrode 4 include the following (1) to (4).
  • Metal electrode A material made of a metal that reflects light such as Au, Ag, Al, Pt, Cu, Mn, Mg, Ca, Li, Yb, Eu, Sr, Ba, Na, etc., and among these metals
  • the alloy formed by selecting two or more types from the above specifically, Mg: Ag, Al: Li, Al: Ca, and Mg: Li.
  • the EL layer 3 is composed of an organic material, among these metals or alloys, those having a work function of 4.0 eV or less are preferable as the cathode, while those having a work function of 4.5 eV or more are preferable as the anode.
  • the transparent electrode itself has a low reflectance, the reflectance can be increased by laminating with the metal film.
  • a conductive oxide film is preferable, and ZnO: Al, ITO, SnO 2 : Sb, or InZnO is particularly preferable.
  • the metal film include films made of the metal or alloy described in (1) above. In this laminated reflective electrode, either a transparent electrode or a metal film may be provided at a portion in contact with the EL layer 3.
  • Dielectric film / transparent electrode or laminated light reflective electrode comprising transparent electrode / dielectric film Since the transparent electrode itself has a low reflectance as described above, a dielectric film having a high refractive index or a low refractive index is used. By laminating, the reflectance can be increased.
  • the high refractive index dielectric film a transparent oxide film or a transparent nitride film having a refractive index of 1.9 or more is preferable, and a sulfide film or a selenide compound is also transparent.
  • a high refractive index dielectric film examples include ZnO, ZrO 2 , HfO 2 , TiO 2 , Si 3 N 4 , BN, GaN, GaInN, AlN, Al 2 O 3 , ZnS, ZnSe, or ZnSSe.
  • a film made of is preferably mentioned.
  • a film formed by dispersing these in a polymer may be used.
  • a film made of a transparent oxide or fluoride having a refractive index of 1.5 or less, or a film formed by dispersing the oxide or fluoride in powder form in a polymer Or a fluorinated polymer film a film made of MgF 2 , CaF 2 , BaF 2 , NaAlF, or SiOF, a film formed by dispersing these compounds in a polymer, or a fluorinated polyolefin or fluorinated polymethacrylate
  • a film made of fluorinated polyimide or the like is preferable.
  • the dielectric multilayer film in the multilayer reflective electrode is a high refractive index dielectric film described in (3) above. And a low-refractive-index dielectric film are preferably laminated alternately and multiple times so that the optical film thickness is ⁇ / 4 ( ⁇ is the wavelength of the emitted light). 50% or more can be suitably realized. Moreover, what was demonstrated by said (2) can be mentioned as a transparent electrode.
  • the first light reflection layer 7 and the second light reflection layer 9 are light reflection layers that sandwich the color conversion layer 8 and constitute a microresonator that enhances the converted light emitted from the color conversion layer 8. Has reflectivity.
  • the reflectance of the first light reflecting layer 7 is preferably 50% or more, more preferably 70% or more, with respect to the converted light emitted from the color conversion layer 8.
  • the second light reflection layer 9 is preferably semi-transmissive to the converted light emitted from the color conversion layer 8 and has a reflectance of 25% or more.
  • the transmittance of the first light reflecting layer 7 is 25% or more and 100% or less with respect to the light emitted from the EL layer 3 which is excitation light.
  • the microcavity structure doubles the amount of emitted light at maximum.
  • each of the EL layer 3 and the color conversion layer 8 is doubled. Therefore, if the transmittance of the first light reflecting layer 7 is 25% or more, it is the same as or more than the configuration without the microcavity structure. The amount of light can be emitted.
  • Examples of the material constituting the first light reflecting layer 7 and the second light reflecting layer 9 include the following (5) to (8).
  • Metal film (6) Laminated light reflecting layer comprising metal film / transparent conductive film or transparent conductive film / metal film (7) Laminated light reflecting layer comprising dielectric film / transparent conductive film or transparent conductive film / dielectric film (8) Dielectric Multilayer Film
  • the above (5) to (7) are the same as the above (1) to (3), respectively. Since the first light reflecting layer 7 and the second light reflecting layer 9 do not need a conductive function, the transparent electrode in the above (4) is not necessary with respect to the above (8).
  • the above (6) and (7) have sufficient reflectivity as a light reflecting film, and therefore need to have a laminated structure of thin films having different refractive indexes, ie, a metal film and a dielectric film, respectively.
  • a transparent conductive film since a light reflecting layer having a sufficient reflectance can be formed only with dielectric films having different refractive indexes, a transparent conductive film may be provided but is not necessary.
  • the configuration of the dielectric multilayer film is the same as that described in the above (4), and the optical film thickness of the high refractive index dielectric film and the low refractive index dielectric film is ⁇ / 4 ( ⁇ is emitted). It is preferable that the layer is formed by alternately laminating a large number of times so that the wavelength of light becomes. According to such a dielectric multilayer film, it becomes easy to set the reflectance with respect to light of a target wavelength to a suitable value.
  • the EL layer 3 in the present embodiment is configured as an organic EL layer including at least an organic light emitting layer that emits blue light or ultraviolet light.
  • the EL layer 3 may have a single-layer structure of an organic light-emitting layer or a multilayer structure of an organic light-emitting layer and a charge transport layer. Specific examples include the following configurations. However, the present invention is not limited to these.
  • organic light emission layer, hole injection layer, hole transport layer, hole prevention layer, electron prevention layer, electron injection layer may have a single layer structure or a multilayer structure.
  • the organic light emitting layer may be composed only of the organic light emitting material exemplified below, or may be composed of a combination of a light emitting dopant and a host material, and optionally a hole transport material, an electron transport material, and Additives (donor, acceptor, etc.) may be included. Moreover, the structure by which the above-mentioned material was disperse
  • the organic light emitting material a known light emitting material for organic EL can be used. Such light-emitting materials are classified into low-molecular light-emitting materials, polymer light-emitting materials, and the like. Specific examples of these compounds are given below, but the present invention is not limited to these materials.
  • the light-emitting material may be classified into a fluorescent material, a phosphorescent material, and the like, and it is preferable to use a phosphorescent material with high emission efficiency from the viewpoint of reducing power consumption.
  • low-molecular organic light-emitting material examples include aromatic dimethylidene compounds such as 4,4′-bis (2,2′-diphenylvinyl) -biphenyl (DPVBi), 5-methyl-2- [2- [4- ( Oxadiazole compounds such as 5-methyl-2-benzoxazolyl) phenyl] vinyl] benzoxazole, 3- (4-biphenylyl) -4-phenyl-5-t-butylphenyl-1,2,4- Examples thereof include triazole derivatives such as triazole (TAZ), styrylbenzene compounds such as 1,4-bis (2-methylstyryl) benzene, and fluorescent organic materials such as fluorenone derivatives.
  • aromatic dimethylidene compounds such as 4,4′-bis (2,2′-diphenylvinyl) -biphenyl (DPVBi), 5-methyl-2- [2- [4- ( Oxadiazole compounds such as 5-methyl-2-benzoxazolyl) phen
  • polymer light emitting material examples include polyphenylene vinylene derivatives such as poly (2-decyloxy-1,4-phenylene) (DO-PPP), and polyspiro such as poly (9,9-dioctylfluorene) (PDAF). Derivatives.
  • a known dopant material for organic EL can be used as the light-emitting dopant optionally contained in the organic light-emitting layer.
  • dopant materials include the following. First, fluorescent light emission such as p-quaterphenyl, 3,5,3,5 tetra-t-butylsecphenyl and 3,5,3,5 tetra-t-butyl-p-quinkphenyl as ultraviolet light emitting materials Materials and the like.
  • a fluorescent light emitting material such as a styryl derivative, bis [(4,6-difluorophenyl) -pyridinato-N, C2 ′] picolinate, iridium (III) (FIrpic), and bis (4 ′, 6 Examples include phosphorescent organic metal complexes such as' -difluorophenylpolydinato) tetrakis (1-pyrazoyl) borate, iridium (III) (FIr6), and the like.
  • a known host material for organic EL can be used as a host material when using a dopant.
  • host materials include the low-molecular light-emitting materials, the polymer light-emitting materials, 4,4′-bis (carbazole) biphenyl, 9,9-di (4-dicarbazole-benzyl) fluorene (CPF), 3 , 6-bis (triphenylsilyl) carbazole (mCP), carbazole derivatives such as (PCF), aniline derivatives such as 4- (diphenylphosphoyl) -N, N-diphenylaniline (HM-A1), 1,3- And fluorene derivatives such as bis (9-phenyl-9H-fluoren-9-yl) benzene (mDPFB) and 1,4-bis (9-phenyl-9H-fluoren-9-yl) benzene (pDPFB) .
  • the charge injection / transport layer is used to efficiently inject charges (holes, electrons) from the electrode and transport (injection) to the light-emitting layer with the charge injection layer (hole injection layer, electron injection layer) and charge. It is classified as a transport layer (hole transport layer, electron transport layer).
  • a transport layer hole transport layer, electron transport layer.
  • Each of these layers may be composed only of the charge injecting and transporting material exemplified below, and may optionally contain additives (donor, acceptor, etc.), and these materials are polymer materials (binding). Resin) or dispersed in an inorganic material.
  • charge injection / transport material a known charge transport material for organic EL or organic photoconductor can be used. Such charge injection / transport materials are classified into hole injection / hole transport materials and electron injection / electron transport materials. Specific examples of these compounds are given below, but the present invention is limited to these materials. It is not something.
  • hole injection / hole transport materials include oxides such as vanadium oxide (V 2 O 5) and molybdenum oxide (MoO 2), inorganic p-type semiconductor materials, porphyrin compounds, N, N′-bis (3-methylphenyl) Aromatic tertiary amine compounds such as -N, N'-bis (phenyl) -benzidine (TPD), N, N'-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (NPD) , Hydrazone compounds, quinacridone compounds, and styrylamine compounds, and polyaniline (PANI), polyaniline-camphor sulfonic acid (PANI-CSA), 3,4-polyethylenedioxythiophene / polystyrene sulfonate (PEDOT) / PSS), poly (triphenylamine) derivative (Poly-TPD), polyvinyl Carbazole (PVCz), poly (p- phenylene
  • the material used as the hole injection layer is the highest occupied molecular orbital (HOMO) than the hole injection transport material used for the hole transport layer. It is preferable to use a material having a low energy level. As the hole transport layer, it is preferable to use a material having a higher hole mobility than the hole injection transport material used for the hole injection layer.
  • HOMO occupied molecular orbital
  • the hole injection / hole transport material In order to improve the hole injection / transport property, it is preferable to dope the hole injection / hole transport material with an acceptor.
  • an acceptor a known acceptor material for organic EL can be used. Although these specific compounds are illustrated below, this invention is not limited to these materials.
  • Acceptor materials include Au, Pt, W, Ir, POCl 3 , AsF 6 , Cl, Br, I, vanadium oxide (V 2 O 5 ), molybdenum oxide (MoO 2 ), and other inorganic materials, TCNQ (7, 7,8,8, -tetracyanoquinodimethane), TCNQF 4 (tetrafluorotetracyanoquinodimethane), TCNE (tetracyanoethylene), HCNB (hexacyanobutadiene), and cyano such as DDQ (dicyclodicyanobenzoquinone) Examples thereof include compounds having a group, compounds having a nitro group such as TNF (trinitrofluorenone) and DNF (dinitrofluorenone), and organic materials such as fluoranyl, chloranil and bromanyl. Among these, compounds having a cyano group such as TCNQ, TCNQF 4 , TCNE, HCNB, and DDQ are more preferable because the
  • an electron injection / electron transport material for example, an inorganic material which is an n-type semiconductor, an oxadiazole derivative, a triazole derivative, a thiopyrazine dioxide derivative, a benzoquinone derivative, a naphthoquinone derivative, an anthraquinone derivative, a diphenoquinone derivative, a fluorenone derivative, And low molecular weight materials such as benzodifuran derivatives, and high molecular weight materials such as poly (oxadiazole) (Poly-OXZ) and polystyrene derivatives (PSS).
  • the electron injection material include fluorides such as lithium fluoride (LiF) and barium fluoride (BaF 2 ), and oxides such as lithium oxide (Li 2 O).
  • the material used for the electron injection layer is the lowest unoccupied molecular orbital (LUMO) energy level than the electron injection transport material used for the electron transport layer. It is preferable to use a material having a high value. In addition, as a material used for the electron transport layer, it is preferable to use a material having higher electron mobility than the electron injection transport material used for the electron injection layer.
  • LUMO unoccupied molecular orbital
  • the electron injection / transport material it is preferable to dope the electron injection / transport material with a donor.
  • a donor a known donor material for organic EL can be used. Specific examples of the donor material are shown below, but the present invention is not limited to these materials.
  • Donor materials include inorganic materials such as alkali metals, alkaline earth metals, rare earth elements, Al, Ag, Cu, and In, anilines, phenylenediamines, and benzidines (N, N, N ′, N′-tetra Phenylbenzidine, N, N'-bis- (3-methylphenyl) -N, N'-bis- (phenyl) -benzidine, N, N'-di (naphthalen-1-yl) -N, N'-diphenyl -Benzidine, etc.), triphenylamines (triphenylamine, 4,4′4 ′′ -tris (N, N-diphenyl-amino) -triphenylamine, 4,4′4 ′′ -tris (N-3 -Methylphenyl-N-phenyl-amino) -triphenylamine, 4,4'4 ''-tris (N- (1-naphthyl)
  • the organic EL layer 3 composed of the light emitting layer, the hole transport layer, the electron transport layer, the hole injection layer, and the electron injection layer described above can be formed by the following method.
  • an organic EL layer forming coating solution in which the above materials are dissolved and dispersed in a solvent
  • a spin coating method a dipping method, a doctor blade method, a discharge coating method, a coating method such as a spray coating method, an inkjet method
  • a known wet process such as a relief printing method, an intaglio printing method, a screen printing method, or a printing method such as a micro gravure coating method can be used.
  • known dry processes such as resistance heating vapor deposition, electron beam (EB) vapor deposition, molecular beam epitaxy (MBE), sputtering, or organic vapor deposition (OVPD) are used for the above materials, or laser transfer. The law etc. can be used.
  • the coating liquid for organic EL layer formation may contain an additive for adjusting the physical properties of the coating liquid, such as a leveling agent or a viscosity modifier.
  • the EL layer 3 is made of an organic EL material
  • the present invention is not limited to this.
  • the EL layer 3 may be realized as a layer including other functional layers.
  • the inorganic EL layer may be composed of an inorganic EL material.
  • the color conversion layer 8 includes a blue conversion layer, a red conversion layer, a green conversion layer, or the like that absorbs ultraviolet or blue excitation light from the EL layer 3 and emits blue, green, or red light. If necessary, the color conversion layer 8 may be a color conversion layer that emits light of cyan or yellow.
  • the color purity of each pixel emitting light of cyan or yellow emits light of red, green, or blue on the chromaticity diagram. It is preferable to be outside the triangle connected by the point of color purity of the pixel. According to such a display device, it is possible to further expand the color reproduction range as compared with a display device that uses pixels that respectively emit the three primary colors of red, green, and blue.
  • the color conversion layer 8 may be composed of only the phosphor material exemplified below, or may be optionally composed of an additive or the like, and these materials are polymer materials (binding resin). Or the structure disperse
  • a known color conversion material can be used as the color conversion material.
  • Such color conversion materials are classified into organic phosphor materials and inorganic phosphor materials. Specific examples of these compounds are given below, but the present invention is not limited to these materials.
  • Organic phosphor materials include, as fluorescent dyes that convert ultraviolet excitation light into blue light emission, stilbenzene dyes: 1,4-bis (2-methylstyryl) benzene, and trans-4,4′-diphenyl Examples thereof include stilbenzene and coumarin dyes: 7-hydroxy-4-methylcoumarin.
  • coumarin dyes 2,3,5,6-1H, 4H-tetrahydro-8-trifluoromethylquinolidine (9,9a, 1-gh) ) Coumarin (coumarin 153), 3- (2′-benzothiazolyl) -7-diethylaminocoumarin (coumarin 6), and 3- (2′-benzoimidazolyl) -7-N, N-diethylaminocoumarin (coumarin 7), and And naphthalimide dyes: basic yellow 51, solvent yellow 11, solvent yellow 116, and the like.
  • cyanine dye 4-dicyanomethylene-2-methyl-6- (p-dimethylaminostyryl) -4H-pyran
  • pyridine dye 1 -Ethyl-2- [4- (p-dimethylaminophenyl) -1,3-butadienyl] -pyridinium-perchlorate
  • rhodamine dyes rhodamine B, rhodamine 6G, rhodamine 3B, rhodamine 101, rhodamine 110, basic violet 11 and sulforhodamine 101 and the like.
  • the inorganic phosphor material as a phosphor that converts ultraviolet excitation light into blue emission, Sr 2 P 2 O 7 : Sn 4+ , Sr 4 Al 14 O 25 : Eu 2+ , BaMgAl 10 O 17 : Eu 2+ , SrGa 2 S 4 : Ce 3+ , CaGa 2 S 4 : Ce 3+ , (Ba, Sr) (Mg, Mn) Al 10 O 17 : Eu 2+ , (Sr, Ca, Ba 2 , Mg) 10 (PO 4 ) 6 Cl 2 : Eu 2+ , BaAl 2 SiO 8 : Eu 2+ , Sr 2 P 2 O 7 : Eu 2+ , Sr 5 (PO 4 ) 3 Cl: Eu 2+ , (Sr, Ca, Ba) 5 (PO 4 ) 3 Cl: Eu 2+, BaMg 2 Al 16 O 27: Eu 2+, (Ba, Ca) 5 (PO 4) 3 Cl: Eu 2+, Ba 3 Mg
  • Y 2 O 2 S Eu 3+ , YAlO 3 : Eu 3+ , Ca 2 Y 2 (SiO 4 ) 6 : Eu 3+ , LiY 9 ( SiO 4 ) 6 O 2 : Eu 3+ , YVO 4 : Eu 3+ , CaS: Eu 3+ , Gd 2 O 3 : Eu 3+ , Gd 2 O 2 S: Eu 3+ , Y (P, V) O 4 : Eu 3+ , Mg 4 GeO 5.5 F: Mn 4+ , Mg 4 GeO 6 : Mn 4+ , K 5 Eu 2.5 (WO 4 ) 6.25 , Na 5 Eu 2.5 (WO 4 ) 6.25 , K 5 Eu 2.5 (MoO 4 ) 6.25 , Na 5 Eu 2.5 (MoO 4 ) 6.25, and the like.
  • the inorganic phosphor may be subjected to a surface modification treatment as necessary.
  • a surface modification treatment As a method thereof, physical treatment by chemical treatment such as a silane coupling agent or addition of fine particles of submicron order, etc. And the like due to the combined treatment thereof.
  • an inorganic phosphor rather than an organic phosphor material.
  • the method for producing the color conversion layer 8 is not particularly limited, and various methods can be used.
  • the film forming method includes a casting method, a spin coating method, a relief printing method, an intaglio printing method, a screen printing method, a printing method such as a micro gravure coating method, a bar coating method, an extrusion molding method, a roll molding method, and a pressing method.
  • organic vapor deposition A dry process, a laser transfer method, or the like can be used.
  • organic solvent examples include dichloromethane, 1,2-dichloroethane, chloroform, acetone, cyclohexanone, toluene, benzene, xylene, N, N-dimethylformamide, dimethyl sulfoxide. 1,2-dimethoxyethane, diethylene glycol dimethyl ether, or the like can be used. These solvents may be used alone or in combination of two or more.
  • the color conversion layer 8 when the color conversion layer 8 is formed, by using a photosensitive resin as the polymer resin, patterning can be performed by a photolithography method.
  • a photosensitive resin a photosensitive resin having a reactive vinyl group such as acrylic acid resin, methacrylic acid resin, polyvinyl cinnamate resin, or hard rubber resin (photo-curable resist material). It is possible to use one kind or a mixture of several kinds.
  • the patterning of the color conversion layer 8 includes a wet process such as an inkjet method, a relief printing method, an intaglio printing method, or a screen printing method, a resistance heating vapor deposition method using a shadow mask, an electron beam (EB) vapor deposition method, It is also possible to directly pattern the phosphor material by a known dry process such as a molecular beam epitaxy (MBE) method, a sputtering method, an organic vapor deposition (OVPD) method, or a laser transfer method.
  • MBE molecular beam epitaxy
  • OVPD organic vapor deposition
  • the inorganic sealing film 5 is formed on the second light reflective electrode 4. By providing the inorganic sealing film 5, it is possible to prevent oxygen and moisture from being mixed into the EL portion 11 from the outside, and the life of the light emitting element 100 can be improved.
  • the resin layer 6 is a resin for bonding the EL element substrate 40 and the phosphor substrate 50 together.
  • a thermosetting resin can be used.
  • the inorganic sealing film 5 and the resin layer 6 can be formed by a well-known material and method, in this embodiment, it is necessary to use a light transmissive material.
  • a pair of light reflective electrodes (first light reflective electrode 2 and second light reflective electrode 4) and a pair of light reflective layers (first light reflective layer 7 and second light reflective layer 9). ) are each configured to form a microresonator structure.
  • the optical film thickness (optical distance) between each reflective interface is made into the specific wavelength among the lights emitted from the EL layer 3.
  • the intensity of light (excitation light) is set to be increased.
  • the optical film thickness (optical distance) between the respective reflective interfaces is set to a light having a specific wavelength among the light emitted from the color conversion layer 8 ( The intensity of light having a desired color tone is set to be increased.
  • the optical film thickness (nd) between the reflective interfaces is expressed by the following formula (1).
  • (Nd) ⁇ 4 ⁇ / ⁇ + ⁇ 2m ⁇ (1) Is set to satisfy the relationship.
  • ⁇ represents the wavelength of light to be enhanced.
  • ⁇ represents the sum of phase changes given by reflections occurring at the two reflective interfaces. For example, it is known that when a reflective interface is provided by a metal, it contributes to ⁇ by ⁇ .
  • m is an integer of 1 to 10.
  • the microresonator structure By configuring the microresonator structure with each of the EL element substrate 40 and the phosphor substrate 50 as described above, the loss of light propagation from the EL layer 3 serving as the excitation light source to the color conversion layer 8 is minimized, In addition, the extraction efficiency of light emission from the color conversion layer 8 can be improved. As a result, the light emission efficiency of the light emitting element 100 can be improved (the luminance in the front direction can be improved).
  • the EL unit 11 has been described as an organic EL, but the present invention is not limited to this and may be an inorganic EL. A configuration example in this case will be described below.
  • the EL unit 11 which is an inorganic EL is configured as an ultraviolet light emitting inorganic EL or a blue light emitting inorganic EL.
  • the 1st light reflective electrode 2 and the 2nd light reflective electrode 4 can use the structure containing a dielectric film among the structures illustrated in the above-mentioned embodiment.
  • a known dielectric material for inorganic EL can be used as the dielectric film.
  • a dielectric material include tantalum pentoxide (Ta 2 O 5 ), silicon oxide (SiO 2 ), silicon nitride (Si 3 N 4 ), aluminum oxide (Al 2 O 3 ), aluminum titanate ( Examples include AlTiO 3 ) barium titanate (BaTiO 3 ) and strontium titanate (SrTiO 3 ), but the present invention is not limited thereto.
  • the dielectric film may be composed of one type selected from the above dielectric materials, or may be a configuration in which two or more types of materials are laminated.
  • the EL layer 3 can use the well-known luminescent material for inorganic EL as a light emitting layer of inorganic EL.
  • a light emitting material for example, ZnF 2 : Gd as an ultraviolet light emitting material, and BaAl 2 S 4 : Eu, CaAl 2 S 4 : Eu, ZnAl 2 S 4 : Eu, Ba 2 as a blue light emitting material.
  • Examples include SiS 4 : Ce, ZnS: Tm, SrS: Ce, SrS: Cu, CaS: Pb, (Ba, Mg) Al 2 S 4 : Eu, but the present invention is not limited thereto.
  • the light emitting element 100 may have a configuration in which the light scattering layer 12 is provided. This modification will be described below with reference to FIG. FIG. 3 is a cross-sectional view showing the light emitting element 110 provided with the light scattering layer 12.
  • the light scattering layer 12 is for scattering light with high directivity emitted from the color conversion layer 8 in the same direction.
  • the light scattering layer 12 is preferably provided on one side of the substrate 10.
  • the present invention is not limited to this, and the light scattering layer 12 may be formed outside the light extraction surface side of the converted light of the color conversion layer 8 so as to be parallel to the light emitting surface of the light emitting element 100. For example, it may be arranged in a state separated from the substrate 10.
  • the light scattering layer 12 include the following (1) to (8).
  • a lens sheet is light that travels straight by a plurality of lenses, prisms, V-grooves, or the like arranged or formed concentrically, in a plurality of parallel lines, or in a lattice pattern. It means a thin plate-like transparent material that changes the direction of the.
  • this lens sheet include a lenticular lens sheet, a Fresnel lens sheet, a fly-eye lens sheet, a cat-eye lens sheet, a double fly-eye lens sheet, a double lenticular lens sheet, and a radial lenticular lens sheet.
  • the lens sheet may be made of glass or resin.
  • the resin include polyethylene terephthalate, polycarbonate, polyethersulfone, polyarylate, polymethacrylate, polyacrylate, and polystyrene.
  • the light scattering layer 12 may be provided on one side of the substrate 10, but the light scattering layer 12 itself also serves as the substrate 10. May be.
  • the thickness is preferably about 0.05 to 5 mm.
  • a light scattering layer 12 on one side of the substrate 10 for example, an epoxy adhesive, an acrylic adhesive, a photocurable resin, a thermosetting resin, a thermoplastic adhesive (vinyl resin adhesive, etc.)
  • a glass plate or a polymer plate to be the light scattering layer 12 is fixed on a desired surface of the substrate 10 using a binder such as an isocyanate ester resin.
  • a transparent substrate or opaque particles having a refractive index different from that of the transparent substrate is dispersed inside the transparent substrate.
  • the light scattering layer 12 itself also serves as the substrate 10.
  • the material of the transparent substrate may be glass or polymer.
  • the transparent substance include bubbles, glass fibers, SiO2 particles, glass beads, and transparent plastic particles.
  • Specific examples of the opaque particles include particles made of carbon, tin oxide, barium sulfate, titanium carbide, titanium nitride, titanium oxide, or opaque plastic, and powders used as antistatic materials (such as zinc oxide and zinc sulfide). A powder coated with tin oxide).
  • These transparent materials and opaque particles preferably have a particle size of 0.1 ⁇ m to several tens of ⁇ m, excluding glass fibers.
  • the glass fiber preferably has a fiber diameter of about 0.1 to 1000 ⁇ m and a fiber length of about 0.1 to 10 mm. These transparent substances and opaque particles may be used alone or in combination.
  • a dye powder such as dioxazine, anthraquinone, or phthalocyanine
  • a fluorescent dye powder such as stilbene, benzimidazole, or benzidine are used alone or You may use together with a transparent substance and / or an opaque particle.
  • the desired amount of transparent substance or the desired amount of opaque particles is fixed on the desired surface of the substrate 10 using the binder exemplified in the above (2).
  • the metal as the light-scattering layer 12 may adhere to the single side
  • Formation of the metal adhering in the form of dots is performed by a vacuum deposition method using a predetermined metal as an evaporation source, a sputtering method using a predetermined metal as a target, a printing method, a coating method, or a spraying method. be able to.
  • the film thickness of the dot-like metal is preferably about 0.01 to 500 ⁇ m.
  • the size (area in plan view) of the metal adhering to the spot shape is preferably 1 to 10000 ⁇ m 2 , but a metal having a size of 1 mm 2 or more may be included.
  • the coverage with the metal adhering in the form of dots on the surface on which the light scattering layer 12 is provided is preferably 5 to 90%.
  • metal examples include gold, platinum, nickel, chromium and aluminum.
  • Non-metallic fiber woven fabric, knitted fabric or non-woven fabric or an array of the non-metallic fibers Specific examples of the non-metallic fibers include natural fibers such as silk, hemp and cotton, and Examples thereof include chemical fibers such as human silk, nylon fibers, polyester fibers, polypropylene fibers, and glass fibers, and the thickness is preferably 0.1 ⁇ m to 1 mm.
  • the array of non-metallic fibers means that the non-metallic fibers are radial, striped, zigzag, twisted, latticed, mesh-like, spiral, concentric, geometric pattern Or an irregularly arranged fiber, and the number of fibers used may be one or more.
  • the pattern as the light scattering layer 12 is drawn on a plane of the substrate 10 or the like. Can be done.
  • non-metallic thin wire examples include printing ink, copying ink, carbon ink, paint, oil and fat, transparent synthetic resin, and the like, and pigments such as white, black, red, blue, or green. Examples include those having a line width of 10 to 2000 ⁇ m (including fluorescent dyes) or pigments added.
  • the color of the thin line is not particularly limited, and a desired color such as transparent, achromatic color (including translucent), or chromatic color (including translucent) is appropriately selected.
  • Specific examples of the pattern drawn by the fine lines include radial, striped, zigzag, distorted, lattice, mesh, spiral, concentric, geometric pattern, and indefinite shape. . When using a pattern drawn with a non-metallic transparent fine line as the light scattering layer 12, the refractive index of the transparent fine line is preferably different from the refractive index of the substrate 10.
  • the above-mentioned narrow groove is a groove having a depth of about 0.1 to 100 ⁇ m whose vertical cross section is V-shaped or U-shaped, and has a width (at the widest portion in the depth direction). Value) of about 0.1 to 500 ⁇ m.
  • the translucent material layer means a layer made of a solid, liquid, or solid solution having a visible light transmittance of 10 to 99%. Specific examples include paraffin (wax), starch paste, grease, silicone grease, dye solution, pigment dispersion, gold colloid solution, soapy water and the like.
  • the thickness of the translucent substance layer varies depending on the material, but is generally 5 to 1000 ⁇ m.
  • the translucent film means a layer having a visible light transmittance of 10 to 90%.
  • the material include paraffin paper, parafilm (paraffin film), embossed transparent Multiple polymer films (transparent polymer film materials are polyethylene terephthalate, polycarbonate, polyethersulfone, polyarylate, polymethacrylate, polyacrylate, etc.), crystalline polymers (crystalline polypropylene, nylon, polystyrene, cellulose, polyvinyl) Alcohol film), Japanese paper, western paper, cellophane, rubber film, and the like.
  • the light-scattering layer 12 having any one of the above configurations in the light-emitting element 100, it becomes possible to emit light with strong directivity emitted from the color conversion layer 8 in the same direction.
  • FIG. 4 is a cross-sectional view schematically showing the display device 200 according to the present embodiment.
  • red pixels 21, green pixels 22, and blue pixels 23 are arranged in an array.
  • Each of the red pixel 21 and the green pixel 22 has the configuration of the light emitting element 100 described above.
  • the first light reflective electrode 2 and the second light reflective electrode 4 constitute a microresonator structure that sandwiches the red color conversion layer 8a and enhances the wavelength of red light.
  • the first light reflective electrode 2 and the second light reflective electrode 4 constitute a microresonator structure that sandwiches the green color conversion layer 8b and enhances the wavelength of green light. .
  • the blue pixel 23 has a configuration similar to the configuration of the light emitting element 100 described above with respect to the EL unit 11, but does not include the color conversion layer 8 and the microresonator structure for the color conversion layer 8.
  • the EL unit 11 is an organic EL and emits light having directivity in the blue region.
  • the loss of light propagation from the EL layer 3 serving as the excitation light source to the color conversion layer 8 is minimized, and the converted light from the color conversion layer 8 layer
  • the taking-out efficiency can be improved.
  • the extraction efficiency of the blue light emitted from the EL layer 3 can be improved. Therefore, the display device 200 can improve the balance of visibility and light emission intensity in each pixel, and further improve the light emission efficiency.
  • the display device 200 is realized as an active drive type display device.
  • the EL unit 11 may be driven by being directly connected to an external circuit.
  • a switching circuit active element
  • an external driving circuit scanning line electrode circuit (source driver), data signal
  • An electrode circuit gate driver and a power supply circuit
  • TFT active layer materials include amorphous silicon (amorphous silicon), polycrystalline silicon (polysilicon), microcrystalline silicon, inorganic semiconductor materials such as cadmium selenide, zinc oxide, indium oxide-gallium oxide- An oxide semiconductor material such as zinc oxide, or an organic semiconductor material such as a polythiophene derivative, a thiophene oligomer, a poly (p-ferylene vinylene) derivative, naphthacene, or pentacene can be given.
  • TFT structure include a staggered type, an inverted staggered type, a top gate type, and a coplanar type.
  • a glass substrate more preferably a metal substrate, a plastic substrate, more preferably a metal substrate, or a plastic substrate can be used.
  • a plurality of scanning signal lines, data signal lines, and TFTs are arranged at intersections of the scanning signal lines and the data signal lines.
  • a metal-insulator-metal (MIM) diode can be used instead of the TFT.
  • the EL unit 11 may be driven by a voltage-driven digital gradation method.
  • two switching and driving TFTs are arranged for each of the pixels 21 to 23, and the driving TFT and the first electrode of the EL element are electrically connected via a contact hole formed in the planarization layer. Connected.
  • a capacitor for setting the gate potential of the driving TFT to a constant potential is disposed so as to be connected to the gate portion of the driving TFT. Further, a planarization layer is formed on the TFT.
  • the driving method of the EL unit 11 in the display device 200 is not limited to the voltage-driven digital gradation method described above, and may be, for example, a current-driven analog gradation method.
  • the number of TFTs is not particularly limited, and a compensation circuit is built in each of the pixels 21 to 23 for the purpose of preventing variations in TFT characteristics (mobility, threshold voltage), so that two or more TFTs are provided.
  • the EL unit 11 may be driven by using it.
  • the light emitting element 100 can be manufactured as follows, for example.
  • the EL portion 11 is formed on the substrate 1 and sealed with the inorganic sealing film 5, thereby manufacturing the EL element substrate 40.
  • the phosphor substrate 50 is manufactured by manufacturing the pair of first light reflection layers 7 and 9 and the red and green color conversion layers 8 corresponding to the respective pixels 21 and 22 on another substrate 10. To do.
  • the EL element substrate 40 and the phosphor substrate 50 are bonded together with a bonding resin (resin layer 6) interposed therebetween.
  • the color conversion layer corresponding to each of the pixels 21 and 22 can be formed by a normal wet process such as photolithography, so that an increase in cost can be suppressed.
  • the display device 200 may have a configuration in which a liquid crystal element is provided between the color conversion layer 8 and the EL unit 11.
  • the liquid crystal element has a function as an optical shutter that selectively transmits light emitted from the EL unit 11 and the like.
  • the liquid crystal element As the liquid crystal element, a known liquid crystal element can be used.
  • the liquid crystal element includes a liquid crystal cell and a pair of deflecting plates that sandwich the liquid crystal cell.
  • the liquid crystal cell has two electrode substrates and a liquid crystal supported between the two electrode substrates.
  • one optically anisotropic layer may be disposed between the liquid crystal cell and one polarizing plate, or the optical anisotropy is provided between the liquid crystal cell and both polarizing plates.
  • the layers may be arranged one by one.
  • the liquid crystal element may be passively driven or may be active driven using a switching element such as a TFT.
  • a switching element such as a TFT.
  • Example 1 As Example 1, the light-emitting element 100 described in Embodiment 1 was manufactured as follows.
  • the phosphor substrate 50 was produced by the following steps.
  • the substrate 10 As the substrate 10, 0.7 mm glass was used, and after washing with water, pure water ultrasonic cleaning 10 minutes, acetone ultrasonic cleaning 10 minutes, isopropyl alcohol vapor cleaning 5 minutes were performed, and dried at 100 ° C. for 1 hour. .
  • silver (Ag) was formed on the substrate 10 by a sputtering method so as to have a film thickness of 10 nm, whereby the semi-transmissive second light reflecting layer 9 was formed.
  • a green color conversion layer 8 having a thickness of 150 nm was formed by vacuum deposition.
  • the optical characteristics of the first light reflection layer 7 include a transmittance of 90% of blue light used as excitation light at a peak wavelength of 450 nm, and reflection at 547 nm, which is the peak wavelength of light emission of the green color conversion layer 8. The rate was 90%.
  • the EL element substrate 40 was produced by the following steps.
  • a 0.7 mm glass was used as the substrate 1 and washed with water, followed by pure water ultrasonic cleaning for 10 minutes, acetone ultrasonic cleaning for 10 minutes, and isopropyl alcohol vapor cleaning for 5 minutes, followed by drying at 100 ° C. for 1 hour.
  • silver (Ag) is formed on the substrate 1 by a sputtering method so as to have a film thickness of 100 nm, and indium-tin oxide (ITO) is formed thereon by a sputtering method so that the film thickness is 20 nm. did.
  • ITO indium-tin oxide
  • the first light reflective electrode 2 as an anode was formed.
  • the first light-reflecting electrode 2 was further patterned into 90 stripes with a width of 160 ⁇ m and a pitch of 200 ⁇ m by a conventional photolithography method.
  • SiO 2 was laminated on the first light-reflecting electrode 2 by a sputtering method, and patterned to cover only the edge portion of the first light-reflecting electrode 2 by a conventional photolithography method.
  • a short side of 10 ⁇ m from the end of the first light reflective electrode 2 is covered with SiO 2 .
  • the substrate 1 is fixed to a substrate holder in a resistance heating vapor deposition apparatus, the pressure is reduced to a vacuum of 1 ⁇ 10 ⁇ 4 Pa or less, and the following organic layers in the EL layer 3 are formed by resistance heating vapor deposition. It was.
  • TAPC 1,1-bis-di-4-tolylamino-phenyl-cyclohexane
  • N, N′-di-l-naphthyl-N, N′-diphenyl-1,1′-biphenyl-1,1′-biphenyl-4,4′-diamine (NPD) was used to form a hole transport layer with a thickness of 40 nm.
  • This blue organic light emitting layer comprises 1,4-bis-triphenylsilyl-benzene (UGH-2) (host material) and bis [(4,6-difluorophenyl) -pyridinato-N, C2 ′] picolinate iridium (III ) (FIrpic) (blue phosphorescent light emitting dopant) was prepared by co-evaporation at a deposition rate of 1.5 ⁇ / sec and 0.2 ⁇ / sec.
  • a hole blocking layer (thickness: 10 nm) was formed on the blue organic light emitting layer using 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).
  • an electron transport layer (thickness: 30 nm) was formed on the hole blocking layer using tris (8-hydroxyquinoline) aluminum (Alq 3 ).
  • an electron injection layer (thickness: 0.5 nm) was formed on the electron transport layer using lithium fluoride (LiF).
  • a semitransparent second light reflective electrode 4 was formed as a cathode as follows.
  • the substrate 1 was fixed to a metal deposition chamber.
  • the shadow mask for forming the second light reflective electrode 4 and the substrate 1 were aligned.
  • the shadow mask has an opening for forming the second light-reflecting electrode 4 having a stripe shape of 500 ⁇ m width and 600 ⁇ m in a direction facing the stripe of the first light-reflecting electrode 2. used.
  • magnesium and silver are co-deposited at a deposition rate of 0.1 ⁇ / sec and 0.9 ⁇ / sec using a vacuum deposition method to form a desired pattern ( (Thickness: 1 nm). Furthermore, in order to emphasize the interference effect and to prevent a voltage drop due to wiring resistance in the second light reflective electrode 4, silver is formed in a desired pattern at a deposition rate of 1 mm / sec (thickness). : 19 nm). The second light reflective electrode 4 was formed by the above process.
  • a microresonator effect (interference effect) is developed between the first light-reflecting electrode 2 and the second light-reflecting electrode 4, and the front luminance can be increased. For this reason, it becomes possible to propagate the light emission energy from the EL section 11 to the color conversion layer 8 more efficiently.
  • the emission peak was adjusted to 460 nm and the half-value width was adjusted to 50 nm by the microresonator effect.
  • the inorganic sealing film 5 made of SiO 2 having a film thickness of 3 ⁇ m was formed by patterning by plasma CVD. At this time, a shadow mask was used so that the inorganic sealing film 5 covered the inside of the sealing area of 2 mm from the end of the EL part 11 on the upper side and the left and right sides of the EL part 11.
  • the EL element substrate 40 is completed through the above steps.
  • the light emitting element 100 was produced using the phosphor substrate 50 and the EL element substrate 40 produced as described above.
  • thermosetting resin is applied to the phosphor substrate 50, the phosphor substrate 50 and the EL element substrate 40 are brought into close contact via the thermosetting resin, and cured by heating at 80 ° C. for 2 hours. Went.
  • This bonding step was performed in a dry air environment (water content: ⁇ 80 ° C.) for the purpose of preventing deterioration of the organic EL due to water.
  • Comparative Example 1 As Comparative Example 1, a light emitting device having the same configuration as Example 1 was prepared except that the first and second light reflecting layers 7 and 9 were not provided. About the preparation method, the process similar to the process demonstrated in Example 1 was performed except not forming the 1st and 2nd light reflection layers 7 and 9. FIG.
  • Example 1 As a result of comparing the luminous efficiencies of the light emitting devices according to Comparative Example 1 and Example 1, the luminous efficiency of Example 1 was improved by about 2 times compared with Comparative Example 1.
  • Example 2 As Example 2, the light-emitting element 110 according to the modification described in Embodiment 1 was manufactured.
  • the light emitting element 110 has the same configuration as the light emitting element 100 according to Example 1 except that the light scattering layer 12 is provided.
  • a prism lens film in which lenses are formed in a plurality of lines parallel to each other was prepared as the light scattering layer 12. Further, a light emitting element was produced by performing the same process as in Example 1, and the prepared prism lens film was fixed to the light extraction surface of the substrate 10 of the produced light emitting element with an epoxy adhesive. Thus, a green light emitting element 110 having a cross-sectional structure as shown in FIG. 3 was completed.
  • Example 2 As a result of measuring the luminous efficiency and the viewing angle characteristics of the light emitting device according to Example 2, the luminous efficiency of Example 2 is high as in Example 1, and further, the viewing angle characteristic better than that of Example 1 is realized. I was able to.
  • the phosphor substrate according to the present invention includes a substrate, a pair of light reflecting layers formed on one of the substrates, and the other light reflecting layer sandwiched between the pair of light reflecting layers and different from the one.
  • a color conversion layer that absorbs excitation light emitted from an external light source on the side opposite to the substrate and emits converted light of a color different from the color of the excitation light.
  • the optical distance between them is set to an optical distance constituting a microresonator that enhances the intensity of the converted light emitted from the color conversion layer.
  • the phosphor substrate according to the present invention can be used for manufacturing a light emitting device.
  • a light-emitting element can be easily produced by combining the phosphor substrate according to the present invention with an external light source such as an electroluminescence (EL) element.
  • the color conversion layer absorbs light emitted from an external light source such as an EL portion as excitation light and emits converted light.
  • the converted light has improved light extraction efficiency by a microresonator structure formed by a pair of reflective films.
  • the phosphor substrate according to the present invention can be easily combined with an EL element constituting a microresonator structure.
  • a light emitting device with improved luminous efficiency can be easily produced.
  • a display device using the phosphor substrate according to the present invention even in the case of manufacturing a top emission type display device, in order to pattern the color conversion layer, wet such as photolithography is used. A process can be used. Therefore, a display device can be easily manufactured by using the phosphor substrate according to the present invention. It is also possible to reduce the manufacturing cost.
  • At least one of the pair of light reflecting layers is a metal film that is semi-transmissive with respect to light.
  • the reflectance of the light reflecting layer can be adjusted so that the buffer effect by the microresonator structure is suitably realized.
  • the other light reflecting layer of the pair of light reflecting layers is composed of a dielectric multilayer film.
  • the dielectric multilayer film preferably has a transmittance of 25% to 100% for the excitation light.
  • a microresonator structure can be comprised suitably, taking in excitation light to an optical conversion layer efficiently.
  • the amount of emitted light is doubled at maximum.
  • the amount of emitted light is doubled by each of the external light source and the color conversion layer.
  • the transmittance of the dielectric multilayer film is 25% or more, it is possible to emit a light amount equal to or higher than that when the microcavity structure is not used.
  • the phosphor substrate according to the present invention is disposed on the opposite side to the color conversion layer with respect to the substrate, and the converted light incident from the color conversion layer side is opposite to the color conversion layer side. It is preferable to further include a scattering layer that scatters toward the side.
  • the converted light emitted with directivity by the microresonator structure is scattered in the light extraction direction by the light scattering layer.
  • the phosphor substrate according to the present invention it is possible to manufacture a light emitting device with improved viewing angle characteristics.
  • the light-emitting element includes a pair of electrodes, an electroluminescence (EL) layer that is sandwiched between the pair of electrodes and emits light, and the opposite side of the EL layer with respect to one of the pair of electrodes. And a color conversion layer that is sandwiched between the pair of light reflection layers and that absorbs light emitted from the EL layer and emits converted light of a color different from the color of the light.
  • the optical distance between the pair of light reflecting layers is set to an optical distance constituting a microresonator that enhances the intensity of the converted light emitted from the color conversion layer. .
  • the pair of reflective films constitute a microresonator without sandwiching the EL layer therebetween.
  • a pair of electrodes can constitute a microresonator structure for the EL layer.
  • the light extraction efficiency of the converted light emitted from the color conversion layer is improved by the microresonator structure formed by the pair of reflective films.
  • a display device when a display device is manufactured using a light emitting element having the above-described structure, a wet process such as photolithography is used to pattern the color conversion layer even when a top emission type device is manufactured. It is possible to use. Therefore, a display device can be easily manufactured by using the light emitting element according to the present invention. It is also possible to reduce the manufacturing cost.
  • the pair of electrodes is a pair of light-reflective electrodes, and the optical distance between the pair of light-reflective electrodes enhances the intensity of light emitted from the EL layer. It is preferable that the optical distance constituting the microresonator is set.
  • the light extraction efficiency of the light emitted from the EL layer is improved by the microresonator structure formed by the pair of light reflecting electrodes. For this reason, the light emitted from the EL layer can be efficiently incident on the color conversion layer. That is, according to the above-described configuration, it is possible to achieve both efficient incidence of excitation light to the color conversion layer and efficient extraction of converted light. Therefore, the light emission efficiency of the light emitting device according to the present invention can be further improved.
  • At least one of the pair of light reflecting layers is a metal film that is semi-transmissive with respect to light.
  • the reflectance of the light reflecting layer can be adjusted so that the buffer effect by the microresonator structure is suitably realized.
  • the light reflecting layer disposed on the EL layer side of the pair of light reflecting layers is composed of a dielectric multilayer film.
  • the dielectric multilayer film has a transmittance of light emitted from the EL layer of 25% or more and 100% or less.
  • a microresonator structure can be comprised suitably, taking in excitation light to an optical conversion layer efficiently.
  • the amount of emitted light is doubled in each of the EL layer and the color conversion layer. For this reason, when the transmittance of the dielectric multilayer film is 25% or more, it is possible to emit a light amount equal to or higher than that when the microcavity structure is not used.
  • the light-emitting element is disposed on the opposite side of the color conversion layer and the EL layer with one of the pair of light reflection layers interposed therebetween, and is incident from the color conversion layer side. It is preferable to further include a scattering layer that scatters the converted light to the side opposite to the color conversion layer scattering.
  • the converted light emitted with directivity by the microresonator structure of the pair of light reflecting layers is scattered in the light extraction direction by the light scattering layer. For this reason, the viewing angle characteristics of the light emitting device according to the present invention can be improved.
  • the EL layer can be composed of an organic EL material or an inorganic EL material.
  • a display device is a display device in which a plurality of light emitting elements including light emitting elements of different colors are arranged in an array, and each of the plurality of light emitting elements includes any one of the above-described light emitting elements. It is characterized by being composed.
  • each pixel in which the light emitting element is arranged light whose light extraction efficiency is improved by the microresonator structure is used. For this reason, according to the display device according to the present invention, it is possible to improve the light emission efficiency in a balanced manner in viewability and light emission intensity of each pixel.
  • the display device preferably further includes an active element connected to the pair of light reflective electrodes.
  • the above configuration can provide an active drive type display device with excellent display quality.
  • the light emission time can be extended as compared with a passive drive display device, and thus a drive voltage for obtaining desired luminance can be reduced, so that power consumption can be reduced.
  • the active element is disposed on the opposite side of the color conversion layer with the pair of light-reflecting electrodes interposed therebetween.
  • a display device with a high aperture ratio can be realized without being affected by TFTs or wirings provided as active elements. As a result, more effective low power consumption can be achieved.
  • the display device according to the present invention further includes a liquid crystal element that is disposed between the EL layer and the color conversion layer and performs switching by voltage.
  • a display device with excellent display quality can be provided by switching the liquid crystal element.
  • the present invention can be suitably used for flat panel displays such as inorganic EL displays and organic EL displays.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electroluminescent Light Sources (AREA)

Abstract

L'invention concerne un élément électroluminescent (100) comprenant : une paire d'électrodes réfléchissant la lumière (2, 4) ; une couche EL (3) émettant de la lumière ; une paire de couches réfléchissant la lumière (7, 9) ; et une couche de conversion de couleur (8) absorbant la lumière émise par la couche EL (3) et émettant une lumière convertie ayant une couleur différente de celle de ladite lumière absorbée. La paire d'électrodes réfléchissant la lumière (2, 4) forme une structure de microrésonateur qui augmente l'intensité de la lumière émise par la couche EL (3). Par ailleurs, la paire de couches réfléchissant la lumière (7, 8) forme un microrésonateur qui augmente l'intensité de la lumière convertie émise par la couche de conversion de couleur (8).
PCT/JP2011/051211 2010-05-21 2011-01-24 Substrat de luminophore, élément électroluminescent et dispositif d'affichage WO2011145358A1 (fr)

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WO2015181678A1 (fr) * 2014-05-30 2015-12-03 Semiconductor Energy Laboratory Co., Ltd. Dispositif électroluminescent, dispositif d'affichage et dispositif électronique
JP2017037121A (ja) * 2015-08-07 2017-02-16 シャープ株式会社 色変換基板および表示装置
WO2017051298A1 (fr) * 2015-09-21 2017-03-30 Sabic Global Technologies B.V. Réflecteur de bragg réparti sur couche de conversion de couleur à micro cavité pour application d'éclairage à diodes électroluminescentes organiques (oled) bleues
CN110346859A (zh) * 2018-04-08 2019-10-18 京东方科技集团股份有限公司 光学谐振腔、显示面板
WO2019234562A1 (fr) * 2018-06-06 2019-12-12 株式会社半導体エネルギー研究所 Dispositif électroluminescent, dispositif d'affichage et dispositif électronique
CN111009617A (zh) * 2018-10-05 2020-04-14 乐金显示有限公司 自发光显示装置

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WO2006008987A1 (fr) * 2004-07-15 2006-01-26 Idemitsu Kosan Co., Ltd. Écran électroluminescent organique
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US10777762B2 (en) 2014-05-30 2020-09-15 Semiconductor Energy Laboratory Co., Ltd. Light-emitting device, display device, and electronic device with color conversion layers
CN106465507A (zh) * 2014-05-30 2017-02-22 株式会社半导体能源研究所 发光装置、显示装置及电子设备
US11545642B2 (en) 2014-05-30 2023-01-03 Semiconductor Energy Laboratory Co., Ltd. Light-emitting device, display device, and electronic device with color conversion layers
WO2015181678A1 (fr) * 2014-05-30 2015-12-03 Semiconductor Energy Laboratory Co., Ltd. Dispositif électroluminescent, dispositif d'affichage et dispositif électronique
TWI719935B (zh) * 2014-05-30 2021-03-01 日商半導體能源研究所股份有限公司 發光裝置、顯示裝置及電子裝置
US10790462B2 (en) 2014-05-30 2020-09-29 Semiconductor Energy Laboratory Co., Ltd. Light-emitting device, display device, and electronic device with color conversion layers
JP2017037121A (ja) * 2015-08-07 2017-02-16 シャープ株式会社 色変換基板および表示装置
WO2017051298A1 (fr) * 2015-09-21 2017-03-30 Sabic Global Technologies B.V. Réflecteur de bragg réparti sur couche de conversion de couleur à micro cavité pour application d'éclairage à diodes électroluminescentes organiques (oled) bleues
US20180241005A1 (en) * 2015-09-21 2018-08-23 Sabic Global Technologies B.V. Distributed bragg reflector on color conversion layer with micro cavity for blue oled lighting application
CN108140745A (zh) * 2015-09-21 2018-06-08 沙特基础工业全球技术公司 用于蓝色oled照明应用的具有微腔的颜色转换层上的分布布拉格反射器
CN110346859B (zh) * 2018-04-08 2023-05-16 京东方科技集团股份有限公司 光学谐振腔、显示面板
JP7315557B2 (ja) 2018-04-08 2023-07-26 京東方科技集團股▲ふん▼有限公司 光共振器、表示パネル
CN110346859A (zh) * 2018-04-08 2019-10-18 京东方科技集团股份有限公司 光学谐振腔、显示面板
JP2021517263A (ja) * 2018-04-08 2021-07-15 京東方科技集團股▲ふん▼有限公司Ｂｏｅ Ｔｅｃｈｎｏｌｏｇｙ Ｇｒｏｕｐ Ｃｏ．，Ｌｔｄ． 光共振器、表示パネル
JPWO2019234562A1 (ja) * 2018-06-06 2021-07-15 株式会社半導体エネルギー研究所 発光装置、表示装置および電子機器
WO2019234562A1 (fr) * 2018-06-06 2019-12-12 株式会社半導体エネルギー研究所 Dispositif électroluminescent, dispositif d'affichage et dispositif électronique
CN111009617A (zh) * 2018-10-05 2020-04-14 乐金显示有限公司 自发光显示装置
CN111009617B (zh) * 2018-10-05 2024-05-24 乐金显示有限公司 自发光显示装置

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