JP2016143658A - Light emitting element and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting element having higher brightness and high color purity, and a display device.SOLUTION: A light emitting element of the present invention includes: a substrate; a light emitting layer provided over the substrate; and a wavelength conversion layer provided over the substrate, absorbing light of a first wavelength emitted from the light emitting layer, and emitting light of a second wavelength. The wavelength conversion layer includes photonic crystals, and the photon state density in a light extraction direction of the photonic crystals has a peak in the vicinity of energy corresponding to the second wavelength.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting element and a display device.

  Thin-screen displays that have opened up LCDs have made remarkable progress, opening up new markets such as smartphones and tablet computers. Organic EL (Electro-Luminescence, Organic Light Emitting Diode, hereinafter referred to as “organic EL”) is said to be the mainstream of next-generation displays.

  The organic EL element is basically composed of an anode / light emitting layer / cathode, and is provided with a hole injecting / transporting layer and an electron injecting / transporting layer as appropriate, for example, an anode / hole injecting / transporting layer / light emitting layer / cathode. In addition, those having a configuration of anode / hole injection transport layer / light emitting layer / electron injection transport layer / cathode are known. The hole injecting and transporting layer has a function of transmitting holes injected from the anode to the light emitting layer. The electron injection transport layer has a function of transmitting electrons injected from the cathode to the light emitter layer.

  Then, by interposing the hole injecting and transporting layer between the light emitting layer and the anode, many holes are injected into the light emitting layer with a lower electric field. Furthermore, electrons injected from the cathode or the electron injection / transport layer into the phosphor layer are accumulated at the interface between the hole injection / transport layer and the phosphor layer because the hole injection / transport layer does not transport electrons, and the luminous efficiency increases. It has been known.

  In order to make such an organic EL element a multicolor light emitting element, for example, (1) a color conversion method in which blue light emission is converted into green or red by fluorescence conversion to obtain multicolor light emission (for example, Patent Documents 1 and 2 (2) White color filter method that converts white light emission into red, green, and blue using a color filter to produce multicolor light emission (see, for example, Non-Patent Document 1), (3) White light is produced by a microresonator. Alternatively, a micro-resonator method or the like that realizes red, green, and blue to emit multicolor light from various colors is known.

  Now, photonic crystals are attracting attention as a new method for controlling the behavior of light. A photonic crystal has a structure in the order of the wavelength of light, and the refractive index distribution also changes in the order of the wavelength of light. For this reason, a phenomenon completely different from that of linear optics assuming a structure sufficiently longer than the wavelength of light appears.

  In recent years, this photonic crystal has been attracting attention because microfabrication and structuring techniques have made remarkable progress and it has become possible to easily produce structures in the wavelength order of light. Photonic crystals can enhance the light absorption and emission of the phosphors therein.

  However, the enhancement wavelength has an angle dependency as described in Non-Patent Reference 1. The display must look the same from any angle. Angular dependence is a fatal drawback. For this reason, it has been difficult to realize a display using photonic crystals.

Japanese Patent Laid-Open No. 3-152897 JP-A-5-255860

Optics Express, Vol. 17, No. 15, p13168-p13177 (2009)

  The wavelength conversion method has two major problems. One is that the light extraction efficiency in the wavelength conversion layer is low. The light that cannot be extracted from the front surface of the display by the wavelength conversion substrate cannot be used as an image, so that the luminance decreases. The second problem is that the color purity is low. If the color purity of the light after wavelength conversion is low, the color reproduction area of the display becomes narrow and a beautiful image cannot be projected.

  One embodiment of the present invention has been made in view of the problems of the prior art, and can provide a light-emitting element and a display device with higher luminance and higher color purity.

  A light-emitting element according to one embodiment of the present invention includes a substrate, a light-emitting layer provided over the substrate, a light-emitting layer provided over the substrate, which absorbs light having a first wavelength emitted from the light-emitting layer, A wavelength conversion layer that emits light of a wavelength, wherein the wavelength conversion layer includes a photonic crystal, and a photon density of states in the light extraction direction of the photonic crystal has energy corresponding to the second wavelength. It has a peak in the vicinity.

  In the light-emitting element of one embodiment of the present invention, the second wavelength is λ, the angular frequency corresponding to the peak of the photon density of states in the light extraction direction of the photonic crystal is W, and the photonic crystal If the period is a, the dimensionless amount (λ · W) / a may be in the range of 0.95 to 1.05.

  In the light-emitting element of one embodiment of the present invention, the wavelength conversion layer may include the photonic crystal and a phosphor material dispersed inside the photonic crystal.

  In the light-emitting element of one embodiment of the present invention, the wavelength at which the emission spectrum of the phosphor material exhibits a peak substantially matches the wavelength at which the photon density of states in the light extraction direction of the photonic crystal exhibits a peak. It is good.

  In the light-emitting element of one embodiment of the present invention, the light extraction direction may be a direction perpendicular to the light emission surface of the wavelength conversion layer.

  In the light-emitting element of one embodiment of the present invention, the light-emitting layer may emit blue light, and the first wavelength light may be the blue light.

  The light-emitting element of one embodiment of the present invention may further include a transmissive layer that transmits light of the first wavelength in a region different from a region where the wavelength conversion layer is formed on the substrate.

  In the light-emitting element of one embodiment of the present invention, at least a part of the wavelength conversion layer may absorb the light having the first wavelength and emit green light.

  In the light-emitting element of one embodiment of the present invention, at least a part of the wavelength conversion layer may absorb the light having the first wavelength and emit red light.

  A display device according to one embodiment of the present invention includes the above light-emitting element.

  According to one embodiment of the present invention, a light-emitting element and a display device with higher luminance and higher color purity can be realized.

1 is a schematic cross-sectional view of an organic EL element (light emitting element) according to an embodiment. The figure which shows a red fluorescent substance layer and a green fluorescent substance layer (one-dimensional photonic crystal). A graph showing a density of states for each of the following three angles in a red phosphor layer and a green phosphor layer in which a high refractive index material and a low refractive index material are alternately laminated in a direction perpendicular to the light extraction direction, The figure which shows the state density for every angle in a red fluorescent substance layer and a green fluorescent substance layer (one-dimensional photonic crystal). The graph which shows the emission spectrum of rumogen red. Graph showing the TiO ₂ nanoparticles (refractive index 2.72), fluororesin (the refractive index 1.35), the density of states of each angle of the three-dimensional photonic crystal (artificial opal) when using a. The figure which shows typically the structure of the organic electroluminescence display which is one Embodiment of the display apparatus which concerns on this invention. (A)-(C) are figures which show the example of a system with a display apparatus provided with the light emitting element which concerns on this invention. (A)-(C) are figures which show the example of a system with a display apparatus provided with the light emitting element which concerns on this invention. (A), (B) is a figure which shows the manufacturing process of an organic EL part. (C) is a figure which shows the manufacturing process of a fluorescent substance part, (D) is a figure which shows the bonding process of an organic EL part and a fluorescent substance part. FIG. 9 is a schematic diagram partially showing a cross-sectional configuration of a liquid crystal display device of Example 6. FIG. 10 is a diagram illustrating a system of Example 7.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

[First Embodiment]
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a schematic cross-sectional view of an organic EL element 100 (light emitting element) according to this embodiment.
The organic EL element 100 includes a substrate 101, a TFT circuit 102, an insulating film 103, a first electrode 104a, an edge cover 105, an organic layer 109, a second electrode 110, a sealing film 111, a sealing layer 112, a transmission layer 115, a color A conversion layer (wavelength conversion layer) 119 and a sealing substrate 120 are provided.

Next, each component of the organic EL element 100 according to the present embodiment will be described.
<Substrate 101>
As the substrate 101, for example, an inorganic material substrate made of glass, quartz or the like, a plastic substrate including polyethylene terephthalate, polycarbazole, polyimide, or the like, an insulating substrate such as a ceramic substrate including alumina, or the like, or aluminum (Al), iron A method of anodizing the surface of a metal substrate containing (Fe) or the like, or a substrate coated with an insulator containing silicon oxide (SiO ₂ ) or an organic insulating material on the substrate, or a metal substrate containing Al or the like And a substrate subjected to insulation treatment.

  However, the substrate 101 that can be used in the present invention is not limited to these. Here, a plastic substrate or a metal substrate is preferable in order to form a curved portion and a bent portion without stress. More preferred are substrates in which a plastic substrate is coated with an inorganic material, and substrates in which a metal substrate is coated with an inorganic insulating material.

  Although it is known that organic EL deteriorates even with a low amount of moisture, the use of the above-described substrate makes it difficult to use water as the biggest problem when a plastic substrate is used as an organic EL substrate. It becomes possible to eliminate the deterioration of the organic EL element due to the transmission.

  In addition, it is possible to eliminate leakage (short circuit) due to protrusions of the metal substrate, which is the biggest problem when the metal substrate is used as an organic EL substrate. Since the film thickness of the organic EL is as very thin as about 100 to 200 nm, it is known that a leak (short) occurs in the current in the pixel portion due to the protrusion.

In the case of forming the TFT circuit 102, a substrate that does not melt at a temperature of 500 ° C. or lower and does not cause distortion is preferable. Further, since a general metal substrate has a coefficient of thermal expansion different from that of glass, it is difficult to form a TFT on the metal substrate with a conventional production apparatus, but the linear expansion coefficient is 1 × 10 ⁻⁵ / ° C. or less. By using a metal substrate that is an iron-nickel alloy of this type and matching the linear expansion coefficient to glass, it becomes possible to form TFTs on the metal substrate at low cost using a conventional production apparatus.

  In the case of a plastic substrate, since the heat-resistant temperature is very low, after forming the TFT circuit 102 on the glass substrate, the TFT circuit 102 is transferred to the plastic substrate to transfer the TFT circuit onto the plastic substrate. Is possible.

  Further, the material of the substrate 101 may be glass. By using glass as the material of the substrate 101, deformation does not occur even in a high temperature process, and moisture does not permeate. Therefore, it is possible to prevent deterioration of the organic EL element.

  Further, when light emitted from the organic layer 109 is extracted from the side opposite to the substrate 101, there is no restriction as the substrate 101. However, when light emitted from the organic layer 109 is extracted from the substrate 101 side, it is transparent or translucent. It is necessary to use a substrate. However, the present invention is not limited to these materials and forming methods.

<TFT circuit 102>
The TFT circuit 102 is provided on the substrate 101.
The TFT circuit 102 is formed in advance on the substrate 101 before the organic EL element is formed, and functions as a switching device and a driving device. When the organic EL element according to the present invention includes the TFT circuit 102, the configuration of the TFT circuit 102 includes a known TFT circuit. In the present invention, a metal-insulator-metal (MIM) diode may be used instead of the TFT circuit 102.

  The active drive type organic EL display employing the organic EL element of the present invention and the TFT circuit 102 that can be mounted on the organic EL display device can be formed using known materials, structures, and formation methods.

  As an active layer material of the TFT circuit 102, for example, amorphous silicon (amorphous silicon), polycrystalline silicon (polysilicon), microcrystalline silicon, inorganic semiconductor materials such as cadmium selenide, zinc oxide, indium oxide-oxide Examples thereof include oxide semiconductor materials such as gallium-zinc oxide, and organic semiconductor materials such as polythiophene derivatives, thiophene oligomers, poly (p-ferylene vinylene) derivatives, naphthacene, and pentacene. Examples of the structure of the TFT circuit include a staggered type, an inverted staggered type, a top gate type, and a coplanar type.

Examples of the method for forming the active layer constituting the TFT circuit 102 include the following methods.
(1) Method of ion doping impurities into amorphous silicon formed by plasma induced chemical vapor deposition (PECVD) method (2) Amorphous silicon by low pressure chemical vapor deposition (LPCVD) method using silane (SiH ₄ ) gas A method of crystallizing amorphous silicon by solid phase growth to obtain polysilicon and then ion doping by ion implantation (3) LPCVD using Si ₂ H ₆ gas or SiH ₄ gas Forming amorphous silicon by PECVD method, annealing with excimer laser or other laser, crystallizing amorphous silicon to obtain polysilicon, then ion doping (low temperature process)
(4) A polysilicon layer is formed by LPCVD method or PECVD method, a gate insulating film is formed by thermal oxidation at 1000 ° C. or higher, an n + polysilicon gate electrode is formed thereon, and then ion doping is performed. To perform (high temperature process)
(5) Method of forming organic semiconductor material by inkjet method or the like (6) Method of obtaining single crystal film of organic semiconductor material

The gate insulating film of the TFT circuit 102 can be formed using a known material. Examples thereof include SiO ₂ formed by PECVD, LPCVD, etc., or SiO ₂ obtained by thermally oxidizing a polysilicon film. Further, the signal electrode line, the scanning electrode line, the common electrode line, the first drive electrode, and the second drive electrode of the TFT circuit used in the present invention can be formed of a known material.
For example, tantalum (Ta), aluminum (Al), copper (Cu), and the like can be given. The TFT circuit 102 of the organic EL panel according to the present invention can be formed with the above-described configuration, but is not limited to these materials, structures, and formation methods.

<Insulating film 103>
The insulating film 103 is disposed between the TFT circuit 102 and the first electrode 104a.
The insulating film 103 can be formed of a known material. For example, silicon oxide (SiO ₂ ), silicon nitride (SiN or Si ₂ N ₄ ), tantalum oxide (TaO or Ta ₂ O ₅ ), etc. Inorganic materials, or organic materials such as acrylic resins and resist materials.
Examples of the formation method include dry processes such as chemical vapor deposition (CVD) and vacuum deposition, and wet processes such as spin coating. Moreover, it can also pattern by the photolithographic method etc. as needed.

  In the present embodiment, the light emitted from the organic layer 109 is extracted from the opposite side (second electrode 110 side) of the substrate 101. Therefore, it is preferable that the insulating film 103 has light shielding properties in order to prevent external light from entering the TFT circuit 102 formed over the substrate 101 and changing TFT characteristics.

Alternatively, the insulating film 103 and a light-blocking insulating film may be combined. Examples of the light-shielding insulating film include a material in which a pigment or dye such as phthalocyanine or quinaclone is dispersed in a polymer resin such as polyimide, a color resist, a black matrix material, or an inorganic insulating material such as NixZnyFe ₂ O ₄ . However, the present invention is not limited to these materials and forming methods.

  Further, when the TFT circuit 102 or the like is formed on the substrate 101, unevenness is formed on the surface thereof, and the unevenness causes an organic EL element defect (for example, a defect of the anode 104, a defect of the organic layer 109, a second electrode). 110 disconnection, a short circuit between the anode 104 and the cathode 110, a decrease in breakdown voltage, or the like) may occur. In order to prevent these defects, a planarization film may be provided over the insulating film 103.

  The planarization film can be formed using a known material, and examples thereof include inorganic materials such as silicon oxide, silicon nitride, and tantalum oxide, and organic materials such as polyimide, acrylic resin, and resist material.

  Examples of the method for forming the planarizing film include dry processes such as CVD and vacuum deposition, and wet processes such as spin coating, but the present invention is not limited to these materials and forming methods. Further, the planarization film may have a single layer structure or a multilayer structure.

<Organic layer 109>
The organic layer 109 is located between the first electrode 104a and the second electrode 110.
The organic layer 109 is configured by sequentially stacking a hole transport layer 106, a light emitting layer 107, and an electron transport layer 108. The light emitting layer 107 emits blue light (first wavelength light).

  The organic layer 109 provided in the organic EL device according to the present invention is not limited to the configuration of the present embodiment, and a single layer structure of the light emitting layer 107 or a multilayer structure of the light emitting layer 107, the hole transport layer 106, and the electron transport layer 108. For example, the following configurations may be mentioned, but the present invention is not limited thereto.

(1) Light emitter layer (2) Hole transport layer / light emitter layer (3) Light emitter layer / electron transport layer (4) Hole transport layer / light emitter layer / electron transport layer (5) Hole injection layer / Hole transport layer / light emitter layer / electron transport layer (6) hole injection layer / hole transport layer / light emitter layer / electron transport layer / electron injection layer (7) hole injection layer / hole transport layer / light emission Body layer / hole prevention layer / electron transport layer (8) hole injection layer / hole transport layer / light emitter layer / hole prevention layer / electron transport layer / electron injection layer (9) hole injection layer / hole Transport layer / electron prevention layer / light emitter layer / hole prevention layer / electron transport layer / electron injection layer

  Here, each of the light emitting layer 107, the hole injection layer, the hole transport layer 106, the hole prevention layer, the electron prevention layer, the electron transport layer 108, and the electron injection layer may have a single layer structure or a multilayer structure.

The organic layer 109 preferably has a structure that exhibits a microcavity effect. It is more desirable to form the microcavity effect by, for example, setting the thickness so as to match the wavelength of light to be increased. In the organic EL pixel, the organic layer 109 is sandwiched between a pair of electrode layers. Of these, one electrode layer (first electrode 104a) is used as a mirror surface total reflection material, and the other electrode layer (second electrode 110) is used as a translucent material for a dielectric mirror. Further, the organic layer 109 is formed to have a different thickness according to the wavelength of light desired to be enhanced by each RGB light. As a result, among the light emitted from the organic layer 109, the light component having a shifted wavelength repeats multiple reflection between the two electrode layers (the first electrode 104a and the second electrode 110) and resonates, so that a desired wavelength is obtained. The output is enhanced.
A transparent electrode 104b is stacked on the first electrode 104a, and the first electrode 104a and the transparent electrode 104b constitute the anode 104.

As a result, it is possible to condense the light emitted from the organic layer 109 in the front direction (provide directivity), to reduce the light emission loss that escapes to the surroundings, and to increase the light emission efficiency in the front. It becomes. This makes it possible to more efficiently transport the emitted light to the color conversion layer 119 and to increase the front luminance.
In addition, the emission spectrum can be adjusted by the interference effect.
Further, the emission spectrum can be adjusted by adjusting to the desired emission peak wavelength and half width. In addition, it is possible to control the spectrum so that the red and green phosphors can be excited more effectively, and it is possible to improve the color purity of the blue pixel.

  The light emitting layer 107 may be composed only of the organic light emitting material exemplified below. For example, you may be comprised from the combination of a luminescent dopant and host material. Moreover, a hole transport material, an electron transport material, an additive (a donor, an acceptor, etc.) etc. may be included arbitrarily. Moreover, the structure by which these materials were disperse | distributed in the polymeric material (binding resin) or the inorganic material may be sufficient. From the viewpoint of luminous efficiency and lifetime, it is preferable that a luminescent dopant is dispersed in the host material.

Examples of the organic light emitting material include known light emitting materials for organic EL. 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 organic light emitting material may be classified into a fluorescent material, a phosphorescent material, and the like, and is preferably a phosphorescent material with high light emission efficiency from the viewpoint of reducing power consumption.
Here, although a specific compound is illustrated below, this invention is not limited to these compounds.

  Examples of the low-molecular organic light-emitting material 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 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.

  Examples of the polymer light-emitting material include polyphenylene vinylene derivatives such as poly (2-decyloxy-1,4-phenylene) (DO-PPP), and polyspiro derivatives such as poly (9,9-dioctylfluorene) (PDAF). Can be mentioned.

  Examples of the light-emitting dopant optionally contained in the organic layer 109 include known dopant materials for organic EL. Examples of such dopant materials include fluorescent materials such as styryl derivatives, bis [(4,6-difluorophenyl) -pyridinato-N, C2 ′] picolinate iridium (III) (FIrpic), bis (4 ′). , 6′-difluorophenylpolydinato) tetrakis (1-pyrazoyl) borateiridium (III) (FIr6), and the like.

  In the present invention, the organic layer 109 preferably emits blue light.

  Moreover, as a host material when using a dopant, the well-known host material for organic EL can be mentioned. As such a host material, the above-described low molecular light emitting material, polymer light emitting material, 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 electric charge includes holes and electrons. For the purpose of more efficiently performing injection of holes and electrons from the electrode and transport (injection) to the light emitting layer 107, a hole injection layer, a hole transport layer 106, an electron transport layer 108, and an electron injection layer are used. . These layers may be composed only of the charge injecting and transporting material exemplified below, and may optionally contain additives (donor, acceptor, etc.) and the like. Moreover, the structure by which these materials were disperse | distributed in the polymeric material (binding resin) or the inorganic material may be sufficient.

  As the charge injecting and transporting material, known materials for organic EL and organic photoconductors can be used. Such charge injecting and transporting materials are classified into hole injecting and transporting materials and electron injecting and transporting materials. Specific examples of these compounds are given below, but the present invention is not limited to these materials.

Examples of the material for the hole injection layer and the hole transport layer 106 include oxides such as vanadium oxide (V ₂ O ₅ ) and molybdenum oxide (MoO ₂ ), inorganic p-type semiconductor materials, porphyrin compounds, and N, N ′. -Bis (3-methylphenyl) -N, N'-bis (phenyl) -benzidine (TPD), N, N'-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (NPD), etc. Low molecular weight materials such as aromatic tertiary amine compounds, hydrazone compounds, quinacridone compounds, styrylamine compounds, polyaniline (PANI), polyaniline-camphor sulfonic acid (PANI-CSA), 3,4-polyethylenedioxythiophene / polystyrene Sulfonate (PEDOT / PSS), poly (triphenylamine) derivative (Poly-TPD), polyvinylcarba Examples thereof include polymer materials such as sol (PVCz), poly (p-phenylene vinylene) (PPV), and poly (p-naphthalene vinylene) (PNV).

  Further, from the viewpoint of more efficiently injecting and transporting holes from the anode (first electrode 104a), the material of the hole injection layer is the highest occupied molecular orbit (from the material of the hole transport layer 106). A material having a low energy level of (HOMO) is preferable. The material of the hole transport layer 106 is preferably a material having higher hole mobility than the material of the hole injection layer.

  In order to improve the hole injection / transport property, it is preferable to dope an acceptor. As the 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), DDQ (dicyclodicyanobenzoquinone) and the like. And 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, DDQ and the like are more preferable because they can increase the carrier concentration more effectively.

Examples of materials for the electron injection layer and the electron transport layer include inorganic materials that are n-type semiconductors, oxadiazole derivatives, triazole derivatives, thiopyrazine dioxide derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, diphenoquinone derivatives, and fluorenone derivatives. Low molecular materials such as benzodifuran derivatives; polymer materials such as poly (oxadiazole) (Poly-OXZ) and polystyrene derivatives (PSS) are used. In particular, examples of the electron injection layer include fluorides such as lithium fluoride (LiF) and barium fluoride (BaF ₂ ), and oxides such as lithium oxide (Li ₂ O).

  From the viewpoint of more efficient injection / transport of electrons from the cathode (second electrode 110), the material of the electron injection layer is the lowest unoccupied molecular orbital (LUMO) energy level than the material of the electron transport layer 108. A material having a higher electron mobility than the material of the electron injection layer is preferable as the material of the electron transport layer 108.

  In order to improve the electron injection efficiency and the electron transport property, it is preferable to dope the material of the electron injection layer and the electron transport layer 108 with a donor. As the donor, a known donor material for organic EL can be used. Although these specific compounds are illustrated below, this 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, benzidines (N, N, N ′, N′-tetraphenyl) Benzidine, 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) -N-phenyl-amino) -triphenylamine, etc.), triphenyldi Compounds having aromatic tertiary amine skeleton such as amines (N, N′-di- (4-methyl-phenyl) -N, N′-diphenyl-1,4-phenylenediamine), phenanthrene, pyrene, perylene There are organic materials such as condensed polycyclic compounds such as anthracene, tetracene and pentacene (however, the condensed polycyclic compound may have a substituent), TTFs (tetrathiafulvalene), dibenzofuran, phenothiazine and carbazole. Among these, a compound having an aromatic tertiary amine as a skeleton, a condensed polycyclic compound, and an alkali metal are more preferable because the carrier concentration can be increased more effectively.

  The organic layer 109 such as the hole injection layer, the hole transport layer 106, the light emitting layer 107, the electron transport layer 108, and the electron injection layer is for forming a light emitting layer in which the above-described materials of each layer are dissolved and dispersed in a solvent. Using coating liquid, spin coating method, dipping method, doctor blade method, discharge coating method, spray coating method and other coating methods, ink jet method, letterpress printing method, intaglio printing method, screen printing method, micro gravure coating method, etc. Known wet processes such as printing methods, and known dry processes such as resistance heating vapor deposition, electron beam (EB) vapor deposition, molecular beam epitaxy (MBE), sputtering, organic vapor deposition (OVPD), etc. It can be formed by a process or a laser transfer method.

  When the organic layer 109 is formed by a wet process, the light emitting layer forming coating liquid may contain additives for adjusting the physical properties of the coating liquid, such as a leveling agent and a viscosity adjusting agent.

  The thickness of each layer is, for example, about 1 to 1000 nm, but preferably 10 to 200 nm. If the film thickness is less than 10 nm, the charge injection characteristics, transport characteristics, confinement characteristics, and the like that are originally required cannot be obtained. In addition, pixel defects due to foreign matters such as dust may occur. On the other hand, when the film thickness exceeds 200 nm, the drive voltage increases due to the resistance component of the organic layer 109, leading to an increase in power consumption.

<First electrode 104a and second electrode 110>
The first electrode 104 a is formed on the TFT circuit 102 via the insulating film 103. The second electrode 110 is formed on the organic layer 109. The first electrode 104a and the second electrode 110 sandwich the organic layer 109.

  Of the first electrode 104 a and the second electrode 110, the second electrode 110 on the light extraction side must be a transmissive electrode layer that transmits at least part of the light emitted from the organic layer 109. In the present embodiment, light emitted from the organic layer 109 is taken out from the second electrode 110. In addition, this invention is not limited to this, The light may be taken out from the 1st electrode 104a and the 2nd electrode 110 may reflect light.

  The first electrode 104 a and the second electrode 110 function as a pair as an anode or a cathode of the organic EL element 100. That is, when the first electrode 104a is an anode, the second electrode 110 is a cathode, and when the first electrode 104a is a cathode, the second electrode 110 is an anode.

  Specific compounds and formation methods are exemplified below, but the present invention is not limited to these materials and formation methods. A known electrode material can be used as an electrode material for forming the first electrode 104a and the second electrode 110.

As an electrode material for forming the anode 104, gold (Au), platinum (Pt), nickel (Ni) or the like having a work function of 4.5 eV or more from the viewpoint of more efficiently injecting holes into the organic layer 109. And oxides (ITO) containing indium (In) and tin (Sn), oxides (SnO ₂ ) of tin (Sn), oxides (IZO) containing indium (In) and zinc (Zn) Etc. are mentioned as transparent electrode materials.

  In addition, as an electrode material for forming the cathode, lithium (Li), calcium (Ca), cerium (Ce), a work function of 4.5 eV or less, from the viewpoint of more efficiently injecting electrons into the organic layer 109, Examples thereof include metals such as barium (Ba) and aluminum (Al), and alloys such as Mg: Ag alloy and Li: Al alloy containing these metals.

  The first electrode 104a and the second electrode 110 can be formed by a known method such as an EB vapor deposition method, a sputtering method, an ion plating method, or a resistance heating vapor deposition method using the above materials. It is not limited to the forming method.

  If necessary, the formed electrode can be patterned by a photolithographic fee method or a laser peeling method, or a patterned electrode can be directly formed by combining with a shadow mask. The film thickness is preferably 50 nm or more. When the film thickness is less than 50 nm, the wiring resistance is increased, which may increase the drive voltage.

  In the case of adopting a configuration that exhibits the microcavity effect for the purpose of improving color purity, light emission efficiency, frontal brightness, and the like, the second electrode 110 is preferably a translucent electrode. The material of the semitransparent electrode can be a metal translucent electrode alone or a combination of a metal translucent electrode and a transparent electrode material, and silver is preferable from the viewpoint of reflectance and transmittance.

  The film thickness of the semitransparent electrode layer is preferably 5 to 30 nm. When the film thickness is less than 5 nm, the light cannot be sufficiently reflected, and the interference effect cannot be obtained sufficiently. On the other hand, when the film thickness exceeds 30 nm, the light transmittance is drastically reduced, so that the luminance and efficiency may be lowered.

  Further, as the first electrode 104a, it is preferable to use an electrode with high reflectivity that reflects light. Examples of electrode materials used at this time include reflective metal electrodes such as aluminum, silver, gold, aluminum-lithium alloys, aluminum-neodymium alloys, and aluminum-silicon alloys, and transparent and reflective metal electrodes (reflective electrodes). And the like.

<Edge cover 105>
The edge cover 105 seals the end of the anode 104.
The organic EL element 100 has the edge cover 105 for the purpose of preventing leakage between the first electrode 104a and the second electrode 110 at the edge portion of the first electrode 104a formed on the substrate 101 side. Is preferred. Here, the edge cover 105 can be formed by a known method such as an EB vapor deposition method, a sputtering method, an ion plating method, or a resistance heating vapor deposition method using an insulating material, and a known dry or wet photolithography. It can be patterned by the method.

  In addition, when the organic EL element which concerns on this invention is provided with the edge cover 105, the formation method is not limited to these formation methods.

  In addition, a known material can be used as the insulating material and is not particularly limited in the present invention, but it is necessary to transmit light. For example, SiO, SiON, SiN, SiOC, SiC, HfSiON, ZrO, HfO, LaO etc. are mentioned. Moreover, as a film thickness, 100-2000 nm is preferable. When the film thickness is 100 nm or less, the insulation is not sufficient, and leakage occurs between the first electrode 104a and the second electrode 110, resulting in an increase in power consumption and non-light emission. In addition, when the film thickness is 2000 nm or more, the film forming process takes time, resulting in deterioration of productivity and disconnection of the second electrode 110 at the edge cover 105.

<Sealing film 111, sealing layer 112, sealing substrate 120>
The sealing film 111 is laminated on the second electrode 110. The sealing layer 112 is on the sealing film 111. As will be described later, the color conversion layer 119 is formed on the sealing layer 112, and the sealing substrate 120 is provided on the light exit surface 119 </ b> A of the color conversion layer 119.

  Thus, it is preferable to provide the sealing film 111 or the sealing substrate 120 in the organic EL illumination that employs the display, the display device, and the organic EL element according to the present invention. The sealing film 111 and the sealing substrate 120 can be formed by a known sealing material and sealing method. For example, a method of sealing an inert gas such as nitrogen gas or argon gas with glass, metal, or the like can be given. Furthermore, it is preferable to mix a hygroscopic agent such as barium oxide in the enclosed inert gas because deterioration of the organic EL due to moisture can be effectively reduced.

Further, the sealing film 111 can be formed by applying or bonding a resin on the second electrode 110 by using a spin coating method, an ODF, or a laminating method. Further, an inorganic film such as SiO, SiON, SiN or the like is formed on the second electrode 110 by a plasma CVD method, an ion plating method, an ion beam method, a sputtering method, etc., and then a resin is applied by a spin coating method, ODF, lamination It can also be set as the sealing film 111 by apply | coating using a method or bonding.
The sealing film 111 can prevent the entry of oxygen or moisture into the element from the outside, and the life of the organic EL element is improved.

The present invention is not limited to these members or forming methods.
In the case where light is extracted from the side opposite to the substrate 101 (second electrode 110 side), a light-transmitting material may be used for both the sealing film 111 and the sealing substrate 120.

<Color conversion layer 119, transmission layer 115>
The color conversion layer 119 is provided on the opposite side of the organic layer 109 with the second electrode 110 that transmits light emitted from the organic layer 109 interposed therebetween. The color conversion layer 119 is formed on the sealing film 111 via the sealing layer 112. The color conversion layer 119 is composed of two phosphor layers, a red phosphor layer 113 and a green phosphor layer 114.

The transmissive layer 115 is a transmissive layer that transmits blue light and adjusts the orientation. In the organic EL element, blue light emitted from the organic layer 109 is transported to the color conversion layer 119, and blue light (first wavelength light) incident on the red phosphor layer 113 is red light (second wavelength light). The blue light incident on the green phosphor layer 114 is converted into green light (second wavelength light) and then emitted.
The blue light incident on the transmissive layer 115 is adjusted in orientation and emitted as blue.

  Here, the red phosphor layer 113 and the green phosphor layer 114 themselves have a structure as a photonic crystal whose refractive index changes in a range of a length on the order of nanometers. Since the red phosphor layer 113 and the green phosphor layer 114 are photonic crystals, the intensity of the emitted light emitted in the light extraction direction is enhanced, and the emitted light with higher luminance can be obtained. Further, since the spectrum of the emitted light has a steep peak, emitted light with high color purity can be obtained.

  The red phosphor layer 113 and the green phosphor layer 114 are themselves photonic crystals, but further include phosphor materials exemplified below. The material constituting the photonic crystal is composed of two or more materials having different refractive indexes, and may optionally contain additives. The structure of the photonic crystal and the manufacturing method are the main part of the present invention and will be described in detail later.

  Further, it is preferable to form a black matrix BM between the red phosphor layer 113, the green phosphor layer 114, and the transmission layer 115.

  As the phosphor material of the present invention, a known phosphor material can be used. Such phosphor materials are classified into organic phosphor materials and inorganic phosphor materials. Specific examples of these compounds are shown below, but the present invention is not limited to these materials.

<Organic phosphor material>
As fluorescent dyes that convert blue excitation light into green light emission, 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), 3- (2′-benzoimidazolyl) -7-N, N-diethylaminocoumarin (coumarin 7), naphthalimide dye : Basic yellow 51, solvent yellow 11, solvent yellow 116, and the like.
More preferably, body pi dyes, squaraine dyes, terbium complex dyes and the like having a sharp peak in the emission spectrum can be used. This is because a dye having a sharp emission spectrum has a high effect of improving the light emission efficiency in the present invention. Details will be described later.

  In addition, as a fluorescent dye that converts blue excitation light into red light emission, cyanine dyes: 4-dicyanomethylene-2-methyl-6- (p-dimethylaminostyryl) -4H-pyran, pyridine dyes : 1-ethyl-2- [4- (p-dimethylaminophenyl) -1,3-butadienyl] -pyridinium-perchlorate and rhodamine dyes: rhodamine B, rhodamine 6G, rhodamine 3B, rhodamine 101, rhodamine 110, And basic violet 11, sulforhodamine 101 and the like.

Other fluorescent dyes may be used.
For example, coumarins, rhodamines, fluoresceins, cyanines, porphyrins, naphthalimides, perylenes, quinacridones and the like are preferable because of high fluorescence quantum yield.
More preferably, body pi dyes, squaraine dyes, europium complex dyes, etc. having a sharp peak in the emission spectrum can be used. This is because a dye having a sharp emission spectrum has a high effect of improving the light emission efficiency in the present invention. Details will be described later. Particularly preferred are those having a fluorescence quantum yield of 0.3 or more when dispersed in a polymer binder. This organic fluorescent substance may be used alone or in combination of two or more.

<Inorganic phosphor material>
As phosphors that convert blue excitation light into green light emission, (BaMg) Al ₁₆ O ₂₇ : Eu ²⁺ , Mn ²⁺ , Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ , (SrBa) Al ₁₂ Si ₂ O ₈ : Eu ²⁺ , (BaMg) ₂ SiO ₄ : Eu ²⁺ , Y ₂ SiO ₅ : Ce ³⁺ , Tb ³⁺ , Sr ₂ P ₂ O ₇ -Sr ₂ B ₂ O ₅ : Eu ²⁺ , (BaCaMg) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , Sr ₂ Si ₃ O ₈ -2 SrCl ₂ : Eu ²⁺ , Zr ₂ SiO ₄ , MgAl11O ₁₉ : Ce ³⁺ , Tb ³⁺ , Ba ₂ SiO ₄ : Eu ²⁺ , Sr ₂ SiO ₄ : Eu ²⁺ , ( BaSr) SiO ₄ : Eu ^{2+ and the} like.

Moreover, as a fluorescent substance which converts blue excitation light into red light emission, 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. Examples of the method include a chemical treatment such as a silane coupling agent, a physical treatment by adding fine particles of submicron order, and a combination thereof. In consideration of stability such as deterioration due to excitation light and light emission, inorganic materials are preferable. When using an inorganic material, it is preferable that the average particle diameter of fluorescent substance particles is 1-50 micrometers. When the average particle diameter of the phosphor particles is 1 μm or less, the luminous efficiency of the phosphor is drastically lowered.

  Further, if the average particle size of the phosphor particles is 50 μm or more, it becomes very difficult to form a flat resin film. In this case, the organic layer 109 having a refractive index of about 1.7 and the red phosphor layer 113, the green phosphor layer 114, and the transmission layer 115 made of an inorganic material having a refractive index of about 2.3 are refracted. Depletion with a rate of 1.0 will occur. When the depletion is completed, the light from the organic layer 109 does not efficiently reach the inorganic fluorescent layer, causing a problem that the light emission efficiency of the color conversion layer 119 is lowered.

  Further, the organic layer 109 is preferably planarized with a planarizing film or the like. Thereby, it is possible to prevent depletion between the organic layer 109, the color conversion layer 119, and the transmission layer 115, and to improve the adhesion between the organic EL portion 1 and the phosphor portion 2.

The organic EL element 100 is composed of pixels that emit at least red, green, and blue, and a full color image can be obtained by appropriately controlling the luminance of the pixels.
Further, it is preferable to add phosphors emitting light of cyan and yellow to the pixels as necessary. Here, by setting the color purity of each pixel emitting light to cyan and yellow outside the triangle connected by the color purity points of red, green, and blue light emitting pixels on the chromaticity diagram, red, The color reproduction range can be further expanded compared to a display and a display device that use pixels that emit three primary colors of green and blue.

<Detailed structure of red phosphor layer 113 and green phosphor layer 114>
As described above, the red phosphor layer 113 and the green phosphor layer 114 have a structure as a photonic crystal. A photonic crystal is a structure whose refractive index changes periodically in the order of the wavelength of light. For example, a one-dimensional photonic crystal whose refractive index changes in a one-dimensional direction can be realized, for example, by a dielectric multilayer film in which two types of dielectric films having different refractive indexes are alternately stacked.

  A three-dimensional photonic crystal can be realized by periodically spreading silica or polymer spheres having the same particle size (particle size in the order of the wavelength of light) by utilizing self-organization. The photonic crystal can control the interaction with light in various ways by controlling the period and the refractive index of the material.

The present invention can be realized with either a one-dimensional photonic crystal or a three-dimensional photonic crystal.
(1D photonic crystal)
FIG. 2 is a diagram showing the red phosphor layer 113 and the green phosphor layer 114 (one-dimensional photonic crystal).
The one-dimensional photonic crystal is also called “dielectric multilayer film”. A one-dimensional photonic crystal can be obtained by periodically laminating two or more materials having different refractive indexes.

  As shown in FIG. 2, the red phosphor layer 113 includes a low refractive index layer 113A made of a fluororesin having a refractive index of 1.35 and a high refractive index layer 113B having a refractive index of 1.76. It is set as the structure laminated | stacked periodically. The green phosphor layer 114 is formed by periodically laminating a low refractive index layer 114A made of a fluororesin having a refractive index of 1.35 and a high refractive index layer 114B having a refractive index of 1.76 with the same film thickness. It is configured. Here, the red phosphor layer 113 and the green phosphor layer 114 have different stacking pitches of the high refractive index layer and the low refractive index layer.

  A one-dimensional photonic crystal can be produced, for example, by performing photolithography a plurality of times using a phosphor layer forming coating solution in which the above phosphor material and resin material are dissolved and dispersed in a solvent. As each photosensitive resin, one kind of photosensitive resin (photo-curable resist material) having a reactive vinyl group such as acrylic resin, methacrylic resin, polyvinyl cinnamate resin, and hard rubber resin. Or it is possible to use several types of mixtures.

  Here, the phosphor material may be dispersed in at least one kind of resin materials to be used. In order to control the film thickness of each layer, it is preferable to control the spin rate, which is the rotation speed of the substrate, by using, for example, a spin coating method when applying the resin.

  When an organic solvent is used in these film forming methods, examples of the organic solvent include dichloromethane, 1,2-dichloroethane, chloroform, acetone, cyclohexanone, toluene, benzene, xylene, N, N-dimethylformamide, dimethyl sulfoxide; 1,2-dimethoxyethane; and diethylene glycol dimethyl ether. These solvents may be used alone or in combination of two or more.

  In addition to the photolithography method, spin coating method, dipping method, doctor blade method, discharge coating method, spray coating method and other coating methods, ink jet method, letterpress printing method, intaglio printing method, screen printing method, microgravure coating Known wet processes such as printing methods, etc., such as resistance heating vapor deposition, electron beam (EB) vapor deposition, molecular beam epitaxy (MBE), sputtering, organic vapor deposition (OVPD), etc. It can be formed by a known dry process or a laser transfer method.

  The total film thickness of the color conversion layer 119 is preferably 1 to 100 μm, for example. By setting the film thickness to 1 μm or more, blue light emission from the organic layer 109 can be sufficiently absorbed. As a result, it is possible to obtain an effect of improving the light emission efficiency and improving the color purity by suppressing the blue transmitted light from being mixed with the required color.

  Furthermore, in order to increase absorption of light emission from the organic layer 109 and reduce blue transmitted light to such an extent that the color purity is not adversely affected, the thickness of the color conversion layer 119 is preferably 1 μm or more. Further, when the film thickness of the color conversion layer 119 is 100 μm, the blue light emission from the organic layer 109 is sufficiently absorbed, so that the efficiency of the material can be maintained while maintaining sufficient efficiency as compared with the case where the thickness is larger than that. Consumption can be suppressed and material costs can be reduced.

  The film thickness of the color conversion layer 119 is more preferably 5 to 100 μm. This is because by setting the film thickness to 5 μm, a sufficient number of periodic structures of a photonic crystal of several hundreds of nanometers in one cycle can be secured, and the properties as a photonic crystal become stronger.

(Example of one-dimensional photonic crystal)
FIG. 3 shows the following density of states for each of the following three angles in the red phosphor layer 113 and the green phosphor layer 114 in which a high refractive index material and a low refractive index material are alternately stacked in a direction perpendicular to the light extraction direction. It is a graph which shows. Here, the light extraction direction is 0 degrees (normal direction), the direction that forms an angle of 30 degrees from the light extraction direction, and the direction that forms an angle of 60 degrees from the light extraction direction. Indicates the density of states.

  Each of the red phosphor layer 113 and the green phosphor layer 114 is made of a fluororesin that is a low refractive index resin having a refractive index of 1.35 and a high refractive index resin having a refractive index of 1.76 with the same film thickness. It is constructed by periodically laminating.

  Note that the light extraction direction is a direction perpendicular to the boundary surface between the color conversion layer 119 and the sealing substrate 120 and from the color conversion layer 119 toward the sealing substrate 120. Almost 100% of light traveling in this direction can be extracted out of the device. Therefore, the light extraction efficiency can be improved by increasing the light emission in the light extraction direction.

Here, ω is the angular frequency of light, and a is the period of the one-dimensional photonic crystal.
a shows the thickness of a total of two layers when a high refractive index layer and a low refractive index layer are stacked one by one.
When ωa / 2πC = 0.295, the state density in the 0 degree direction has a peak.

  When the emission spectra of the phosphors included in the red phosphor layer 113 and the green phosphor layer 114 include a wavelength corresponding to ωa / 2πC = 0.295, the light having this peak wavelength is amplified and a fluorescence enhancement phenomenon occurs. . When the emission spectrum of the fluorescent dye has a peak at a wavelength corresponding to ωa / 2πC = 0.295, light emission in the 0-degree direction becomes very strong at this peak wavelength. Here, the “emission spectrum” indicates an emission spectrum in a uniform solvent.

  On the other hand, the density of states in other angular directions at this peak wavelength has a peak on the higher frequency side (short wavelength side), and therefore does not have a peak as shown in FIG. Therefore, no fluorescence enhancement occurs in other angular directions. That is, it is possible to increase the proportion of light traveling in the 0 degree direction among light emitted by the phosphor (for example, green light or red light).

As an example, a case where luminogen red which emits red light is used as a fluorescent dye is given.
FIG. 3 is a diagram showing the state density for each angle in the red phosphor layer 113 and the green phosphor layer 114 (one-dimensional photonic crystal). FIG. 4 shows the emission spectrum of lumogen red.

As shown in FIG. 4, this fluorescent dye has an emission spectrum peak at 603 nm.
In order to overlap the peak wavelength of the fluorescence spectrum with the peak of the state density in the 0 degree direction, 603 nm, that is, the angular frequency ω = 3.13 × 10 ¹⁵ may be substituted for ωa / 2πC = 0.295 to obtain a. Then, a = 178 nm.
That is, the high refractive index layer 113B and the low refractive index layer 113A may be alternately stacked with a thickness of about 89 nm (= a / 2). Then, the light emission of rumogen red is enhanced in the 0 degree direction, and the light extraction efficiency is improved. In addition, color enhancement is improved because enhancement occurs only within a narrow range of around 603 nm.

  Thus, when the wavelength of the converted light is λ, the angular frequency corresponding to the peak of the photon state density in the light extraction direction of the photonic crystal is W, and the period of the photonic crystal is a, the dimensionless amount (Λ · W) / a may be in the range of 0.95 or more and 1.05 or less.

In addition, the wavelength corresponding to the peak of the photon state density is not necessarily the peak of the emission spectrum of the fluorescent dye.
For example, it is said that light having a wavelength of about 620 nm is best for red pixels for display. At this time, even if lumogen red is used as a red fluorescent dye, the wavelength may be shifted from 603 nm, which is the peak of the emission spectrum, and 620 nm may be a wavelength corresponding to the peak of the state density. That is, when the thickness of each layer is about 91.5 nm, a high-quality display with a wider color reproduction region can be obtained.

  Further, the case where the fluorescent dye using rare earth elements is used is considered to be most effective as the present invention. A europium complex using one of the rare earths, europium, has a steep peak at 612 nm with a half-width of 10 nm or less. When the wavelength corresponding to the peak of state density is combined with this peak, the emission enhancement of 612 nm can be achieved and the color purity can be made very high. In the configuration shown in FIG. 2 described above, the thickness of each layer may be about 90 nm.

  In the present invention, the wavelength range in which fluorescence can be enhanced is relatively narrow. However, since rare earth complexes such as euromum complexes are biased in a narrow emission spectrum, the ratio of the wavelength range in which fluorescence can be enhanced is high with respect to the entire emission spectrum. Therefore, the light emission is more concentrated only in the target direction, and the rate of improvement of the light emission efficiency itself is higher. That is, the present invention is particularly compatible with fluorescent dyes having a sharp peak, particularly rare earth complexes, and is highly effective. In addition, it has good compatibility with phosphors having a steep emission spectrum peak such as body pi dyes.

(Demonstration of the implementation of this patent when using a one-dimensional photonic crystal)
A portion of the wavelength conversion layer of the light emitting element is peeled from another layer, cut in the cross-sectional direction of the film, and the cross section is viewed. When the cross section is observed with SEM, TEM, etc., when two or more materials that are periodically different are arranged at intervals of the wavelength order of light (especially 100 nm to 400 nm), the wavelength conversion layer is a photonic crystal. Can be considered. Moreover, since the wavelength conversion material is contained in at least one of the plurality of materials, it can be confirmed that the wavelength conversion material uses a photonic crystal.

(3D photonic crystal)
(Artificial opal)
The three-dimensional photonic crystal can be formed in a self-organizing manner, for example, by dispersing SiO ₂ or TiO ₂ nanoparticles in a liquid resin before curing and depositing on the sealing layer 112. The nanoparticles form a three-dimensional photonic crystal by forming a periodic structure in a close-packed structure, that is, a face-centered cubic lattice. In addition to forming in a self-organized manner, coating methods such as photolithography, spin coating, dipping, doctor blade, discharge coating, spray coating, ink jet, letterpress printing, intaglio printing, screen printing A known wet process using a printing method such as a microgravure coating method, resistance heating vapor deposition, electron beam (EB) vapor deposition, molecular beam epitaxy (MBE), sputtering, organic vapor deposition ( It can be formed by a known dry process such as an OVPD method or a laser transfer method.

FIG. 5 shows the state density for each angle of the three-dimensional photonic crystal (artificial opal) when TiO ₂ nanoparticles (refractive index: 2.72) and fluorine tree (refractive index: 1.35) are used. .
When an artificial opal is created by self-organization, the artificial opal having a face-centered cubic lattice structure has (1,1,1) that the bottom surfaces of the red phosphor layer 113 and the green phosphor layer 114 are face-centered cubic lattices. It is formed to be a surface. Therefore, the light extraction direction is the [1, 1, 1] plane.

Here, ω is the angular frequency of light, and a is the lattice constant of the face-centered cubic lattice.
When ωa / 2πC = 0.46, the state density in the [111] direction has a peak.
When the emission spectra of the phosphors included in the red phosphor layer 113 and the green phosphor layer 114 include a wavelength corresponding to ωa / 2πC = 0.46, light having this peak wavelength (light in the [111] direction) is generated. Amplified and a fluorescence enhancement phenomenon occurs.

  Here, when the emission spectrum of the fluorescent dye has a peak at a wavelength corresponding to ωa / 2πC = 0.46, the light emission in the 0 degree direction becomes very strong at this peak wavelength. Here, the “emission spectrum” indicates an emission spectrum in a uniform solvent.

  On the other hand, since the density of states in other angular directions at this peak wavelength has peaks at different wavelengths, the emission spectrum of the fluorescent dye does not overlap with the peak, and the emission in other angular directions is enhanced by the [111] direction. Not. That is, the proportion of light traveling in the [111] direction among the light emitted by the fluorescent dye can be increased.

As an example, a case where luminogen red which emits red light is used as a fluorescent dye is given.
FIG. 4 is a graph showing an emission spectrum of lumogen red.
As shown in FIG. 4, the fluorescent dye that is red-emitting lumogen red has an emission spectrum peak at 603 nm. In order to overlap the peak wavelength of the fluorescence spectrum with the peak of the state density in the 0 degree direction, a = 178 nm may be set. That is, considering the structure of a face-centered cubic lattice, 63 nm nanospheres may be used.

  Further, the wavelength corresponding to the peak of the state density is not necessarily the peak of the emission spectrum of the fluorescent dye. For example, light having a wavelength of about 620 nm is best for red pixels for display. At this time, even if lumogen red is used as a red fluorescent dye, the wavelength may be shifted from 603 nm, which is the peak of the emission spectrum, and 620 nm may be a wavelength corresponding to the peak of the state density. That is, when the thickness of each layer is about 91.5 nm, a high-quality display with a wider color reproduction region can be obtained.

  Similar to the one-dimensional photonic crystal, the light extraction efficiency is obtained by superimposing the peak wavelength of the fluorescent dye (for example, europium complex / terbium complex) having a very steep emission spectrum peak and the state density peak in the light extraction direction. Improvement and luminous efficiency can be improved.

(Dimensionless / generalized)
Generally speaking, regardless of the dimension of the photonic crystal, the peak W of the density of photons at the angle at which light is to be extracted is assumed to be the period (lattice constant) a of the photonic crystal and the wavelength λ to be enhanced in fluorescence. Is

  In other words, since 2πC = / ω = λ,

であればよい。

If it is.

  Further, the error of ± 5% is within the allowable range. This

と示す。

It shows.

  That is, the color conversion layer 119 includes a photonic crystal, and the photon density in the light extraction direction of the photonic crystal has a peak in the vicinity of energy corresponding to red light and green light.

(Demonstration of the implementation of this patent when using a three-dimensional photonic crystal)
A portion of the wavelength conversion layer of the light emitting element is peeled from another layer, cut in the cross-sectional direction of the film, and the cross section is viewed. When the cross section is observed with SEM, TEM, or the like, and the nanoparticles are periodically arranged, it can be regarded as a photonic crystal.

  Further, in the case of an artificial opal, it can be said that the artificial opal has a substantially periodic structure when the volume occupation ratio in the red phosphor layer 113 or the green phosphor layer 114 is about 70 to 74%. This is because when the spheres are packed most densely in a three-dimensional space, they are always arranged in a close-packed structure (face-centered cubic lattice or hexagonal close-packed) periodic structure.

  Moreover, it can confirm that it is a wavelength conversion material using a photonic crystal because the wavelength conversion material is contained in at least 1 of the resin material which fixes the nanoparticle or the structure.

<Other components>
In addition to the above components, a color filter can be provided between the sealing substrate 120 on the light extraction side and the red phosphor layer 113, the green phosphor layer 114, and the transmission layer 115. A conventional color filter can be used as the color filter. Here, by providing the color filter, the color purity of the red pixel, the green pixel, and the blue pixel can be increased, and the color reproduction range of the organic EL display and the organic EL display device can be expanded.

  Further, since the red color filter disposed on the red phosphor layer 113 and the green color filter disposed on the green phosphor layer 114 absorb the blue component and the ultraviolet component of the external light, the phosphor layer by the external light It is possible to reduce or prevent the emission of light and to reduce or prevent a decrease in contrast.

  A polarizing plate can be provided on the light extraction side. As the polarizing plate, a combination of a conventional linear polarizing plate and a λ / 4 plate can be used. Here, by providing the polarizing plate, it is possible to prevent external light reflection on the electrodes of the organic EL display and the organic EL display device, and external light reflection on the surface of the substrate or the sealing substrate. The contrast of the organic EL display device can be improved.

  In the present embodiment, the case where the organic layer 109 is an organic electroluminescence light emitting layer is described, but the present invention is not limited to this. For example, a light emitting diode (LED) such as a blue light emitting diode may be employed as the organic layer 109. In addition, when an LED is employed, blocking and transmission of light emitted by the liquid crystal may be controlled.

<Effect>
The organic EL element 118 according to the invention forms a photonic crystal in the red phosphor layer 113 and the green phosphor layer 114, and wavelength-converts the traveling direction of the wavelength-converted light intentionally in the extraction direction. The light extraction efficiency afterwards is improved. As a result, the power consumption of the entire light emitting element is reduced.

  The organic EL display is required to have higher definition. However, as the definition increases, the number of banks that block between pixels also increases, and the proportion of non-light-emitting regions increases. Therefore, the power consumption of a high-definition display with the same size increases. The present invention is particularly effective in reducing the power consumption of such a high-definition display.

<Display, display device>
Moreover, a display (for example, organic EL display etc.) provided with the light emitting element which concerns on this invention, and a display apparatus (for example, organic display apparatus etc.) are also in the category of this invention. Accordingly, it is possible to realize a high-quality display and display device with higher brightness and wider viewing angle.

Here, an example of the display device according to the present invention will be described with reference to FIG.
FIG. 6 is a diagram schematically showing the structure of an organic EL display device (display device) 700 which is an embodiment of the display device according to the present invention. The organic EL display device 700 includes an organic EL panel 701, a video signal driving circuit 702, a scanning circuit 703, a CPU 704, a controller 705, and an organic EL power supply circuit 706.

  The CPU 704 receives an image signal from a tuner (not shown) or the like. A signal indicating a driving method of the video signal driving circuit 702 and the scanning circuit 703 is created based on the image signal, and the signal is sent to the controller 705. The controller 705 drives the video signal driving circuit 702 and the scanning circuit 703 based on the signal. Specifically, the scanning circuit 703 sends a scanning signal to the scanning line in the organic EL panel 701. The video signal driving circuit 702 sends a video signal to the data line in the organic EL panel. At this time, the organic EL power supply circuit 706 supplies an appropriate voltage to the video signal driving circuit 702 and the scanning circuit 703.

  The display device according to the present invention is not limited to the organic EL display device, and may be a liquid crystal display device, for example.

  When the display device according to the present invention is a liquid crystal display device, reference numeral 701 is a liquid crystal panel and reference numeral 706 is a liquid crystal power supply circuit.

  In the light emitting device according to the present invention, the light emitting layer 107 may emit blue light, and the color conversion layer 119 may be a phosphor layer that converts blue light into fluorescence.

  The phosphor layer includes a red phosphor layer 113 that converts blue light emitted from the light emitting layer 107 into red, and a green phosphor layer 114 that converts blue light emitted from the light emitting layer 107 into green. It may be configured.

  According to said structure, it is the color conversion method which discharge | releases blue light with the light emitting layer 107, and converts the blue light into red light and green light by the red fluorescent substance layer 113 and the green fluorescent substance layer 114, respectively. By arranging the fluorescent dye in the photonic crystal, it is possible to enhance light emission from a specific wavelength (the peak wavelength of the state density in the light extraction direction of the photonic crystal) only in the light extraction direction. Thereby, the emitted light with high brightness and high color purity can be obtained.

  In addition, the light-emitting element according to the present invention includes the first electrode 104a and the second electrode 110 that sandwich the light-emitting layer 107, and the second electrode 110 is a semi-transmissive electrode layer. In addition, the first electrode 104a, the second electrode 110, and the light emitting layer 107 are preferably configured to exhibit a microcavity effect. According to this configuration, the brightness and color purity of the output light are greatly improved due to the expression of the microcavity effect.

The light-emitting element according to the present invention may further include a transmissive layer 115 that transmits blue light without converting the color, and the transmissive layer 115 may include the above-described TiO ₂ nanoparticles. According to this configuration, the luminance of blue light passing through the transmission layer 115 can be improved.

  The color conversion layer 119 includes a red phosphor layer 113 that converts blue light emitted from the organic layer 109 into red, and a green phosphor layer 114 that converts blue light emitted from the organic layer 109 into green. The size of the phosphor particles contained in the red phosphor layer 113, the size of the phosphor particles contained in the green phosphor layer 114, and the size of the metal nanoparticles contained in the transmission layer 115 may be different from each other.

  According to this configuration, the luminance of light having a predetermined wavelength is more effectively increased by optimizing the size of the particles contained in each of the red phosphor layer 113, the green phosphor layer 114, and the transmission layer 115. be able to.

  In the light-emitting element according to the present invention, the particles may be mixed with the fluorescent particles in the color conversion layer 119 or the transmission layer 115 or may be disposed on the surface near the organic layer 109.

In addition, a particle film may be formed in the color conversion layer 119 or on the surface of the transmission layer 115 on the side close to the organic layer 109.
As described above, high-luminance outgoing light can be obtained with any configuration.

In the light-emitting element according to the present invention, the particles may be a metal. The particles may be spherical or may have shapes that differ in at least two cross-sections that are orthogonal to each other.
Further, the particles may be formed by aggregation of a plurality of particles, or may be composed of a metal and a dielectric.
Thus, with any configuration, it is possible to obtain high-luminance outgoing light.

  In the light emitting device according to the present invention, the organic layer 109 may be an organic electroluminescence light emitting layer. According to this configuration, it is possible to obtain an organic electroluminescence element with higher luminance and a wider viewing angle.

<System>
In addition, as an example of a system having a display device including a light emitting element according to the present invention, a system shown in FIGS. 7A to 7C can be considered.
As shown in FIG. 7A, a system 1000 includes a light emitting element 1001 according to the present invention on a front surface, and a battery, a communication module, and the like are built in a main body portion 1002. The system 1000 is, for example, a smart photon, a tablet personal computer, an electronic book, an electronic album, an electronic textbook, an electronic dictionary, or the like, but is not limited thereto. In the case of battery driving, since the battery capacity is limited, the use time can be extended by reducing the power consumption using the light emitting element 1001 according to the present invention.

  Further, as shown in FIG. 7B, a system 1100 is a television that includes the light emitting element 1101 according to the present invention on the front surface and has a main body portion 1102 with a tuner. Since the larger the TV, the larger the power consumption. Therefore, the power consumption can be greatly reduced by using the light emitting element 1101 according to the present invention.

  Further, as shown in FIG. 7C, a system 1200 is a timepiece using the light emitting element 1201 according to the present invention in a dial 1202 portion. By using the light emitting element 1201 according to the present invention for the dial 1202, not only the time display function but also various information such as a weather forecast can be displayed.

In addition, the light-emitting element according to the present invention can be used in the same manner as shown in FIGS.
The light-emitting element according to the present invention includes, for example, a flexible display (system 1300) that can be bent as shown in FIG. 8A and an elliptical display (system 1400) that is not rectangular as shown in FIG. 8B. Or a folding display (system 1500) as shown in FIG.

  As shown in FIG. 8A, the system 1300 is a wearable display such as a tablet PC or a smart phone, and includes a light emitting element 1301 according to the present invention on the front surface of a main body portion 1302. If it is applied to a wearable display, it is flexible so that the wearability is improved.

  As shown in FIG. 8B, the system 1400 is an elliptical display including the light emitting element 1401 according to the present invention on the front surface of the main body portion 1402, and can be used as a television or electronic advertisement with improved interior characteristics. .

  As shown in FIG. 8C, the system 1500 is a foldable display including a light emitting element 1501 according to the present invention on the front surface of a main body portion 1502. Utilizing the advantage of being foldable, it can be used, for example, as a paperback book type or new book type electronic book.

Below, the organic EL element 100 of a present Example is demonstrated.
The organic EL element 100 of this example was manufactured as follows.

<Production of organic EL element 100>
First, the organic EL part 1 and the phosphor part 2 were respectively produced.

<Organic EL part 1>
(1. Selection of substrate 101)
A glass substrate having a thickness of 0.7 mm was used as the substrate 101 of the TFT circuit.

FIGS. 9A to 9D and FIGS. 9A and 9B are diagrams illustrating a manufacturing process of the organic EL unit 1.
(2. Formation of anode)
First, as illustrated in FIG. 9A, the anode 104 is formed over the substrate 101. A first electrode 104a made of silver was formed to a thickness of 100 nm by a sputtering method, and then a transparent electrode 104b made of ITO (Indium Soot) was formed thereon to a thickness of 20 nm by a sputtering method. Patterning was performed on 90 2 mm-wide stripes by photolithography.

Next, after depositing 200 nm of SiO ₂ by sputtering, patterning is performed so that the edge portion (width 10 μm) of the anode 104 is covered with SiO ₂ , and an edge cover 105 is formed as shown in FIG. 9B. did. After the patterning is completed, ultrasonic cleaning for 10 minutes in pure water and ultrasonic cleaning for 10 minutes in acetone are performed. Thereafter, steam cleaning was further performed using isopropyl alcohol for 5 minutes, followed by drying at 100 ° C. for 1 hour.

(3. Formation of the organic layer 109)
The substrate 101 on which the above operation (2. formation of the anode 104) has been performed is fixed to a substrate holder in an in-line type resistance heating vapor deposition apparatus, and the pressure is reduced to a vacuum of 1 × 10 ⁻⁴ Pa or less, whereby the organic layer 109 Formed. In this embodiment, the organic layer 109 has a multilayer structure including a hole injection layer / hole transport layer / organic light emitting layer / hole prevention layer / electron transport layer / electron injection layer.

First, 1,1-bis-di-4-tolylamino-phenyl-cyclohexane (TAPC) was formed to a thickness of 100 nm by resistance heating vapor deposition to form a hole injection layer.
Next, N, N′-di-1-naphthyl-N, N′-diphenyl-1,1′-biphenyl-1,1′-biphenyl-4,4′-diamine (NPD) is obtained by resistance heating vapor deposition. A film was formed to a thickness of 40 nm, and a hole transport layer 106 was formed as shown in FIG.

  Subsequently, 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) were co-deposited at a deposition rate of 1.5 Å / sec and 0.2 Å / sec to form a film thickness of 30 nm, as shown in FIG. A light emitting layer 107 was formed. In the present embodiment, the light emitting layer 107 is a blue light emitting layer.

Next, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was used to form a film with a thickness of 10 nm to form a hole blocking layer. Further, tris (8-hydroxyquinoline) aluminum (Alq ₃ ) was used to form a film with a thickness of 30 nm, so that an electron transport layer 108 was formed as illustrated in FIG.

Finally, lithium fluoride (LiF) was used to form a film with a thickness of 0.5 nm to form an electron injection layer.
In this way, an organic layer 109 was formed on the substrate 101.

(4. Formation of cathode 110)
As shown in FIG. 10A, a cathode (second electrode) 110 is formed on the organic layer 109.
In forming the cathode, first, the substrate 101 on which the anode 104 and the organic layer 109 were formed was fixed to a metal deposition chamber.

  Next, a surface of the organic layer 109 is covered with a cathode forming shadow mask provided with openings so that a stripe-shaped cathode 110 having a width of 2 mm can be formed in a direction perpendicular to the stripe of the anode 104. Thereafter, magnesium and silver are co-evaporated under the conditions of 0.1 Å / sec and 0.9 １ / sec, respectively, by vacuum deposition to form a desired pattern so as to have a film thickness of 1 nm, thereby forming the cathode 110. did.

  Subsequently, silver was vapor-deposited under the conditions of 1 kg / sec to form a desired pattern so as to have a film thickness of 19 nm. By providing this silver layer, the microcavity effect is emphasized, and a voltage drop due to wiring resistance at the cathode 110 can be prevented.

  In the present embodiment, the organic EL element 100 has a microcavity effect between the anode 104 and the cathode 110 by using the anode 104 as a reflective electrode and the cathode 110 as a semi-transmissive electrode. As a result, light emission is adjusted to a peak of 460 nm and a half-value width of 50 nm, the front luminance is increased, and light emission energy from the organic layer 109 can be transported to the color conversion layer 119 more efficiently.

Next, SiO ₂ was formed to a thickness of 3 μm by plasma CVD, and a sealing film 111 made of an inorganic material was formed as shown in FIG. Using a shadow mask, the sealing film 111 was patterned from the edge of the display portion to a sealing area of 2 mm in the vertical and horizontal directions.

  The organic EL part 1 is manufactured by the steps according to the above (1. Selection of the substrate 101), (2. Formation of the anode 104), (3. Formation of the organic layer 109), (4. Formation of the cathode 110). did.

<Production of phosphor part 2>
FIG. 10C is a diagram illustrating a manufacturing process of the phosphor portion 2.
(1. Selection of sealing substrate 120)
As shown in FIG. 10C, a glass substrate having a thickness of 0.7 mm was used as the sealing substrate 120. On the sealing substrate 120, a red phosphor layer 113, a green phosphor layer 114, and a transmission layer 115 each having a width of 3 mm were formed.

(2. Formation of red phosphor layer 113, green phosphor layer 114, and transmissive layer 115)
A: Formation of red phosphor layer 113 First, a red phosphor forming coating solution in which a fluororesin (refractive index of 1.35 upon curing) and lumogen red (0.5 weight percent with respect to the fluororesin) are dissolved in a solvent. Create 1. The obtained red phosphor-forming coating solution 1 was applied to a desired position with a width of 3 mm on a glass substrate by spin coating. At this time, the spin rate was applied at 2000 rpm. Thereafter, heating and drying were performed in a vacuum oven (200 ° C., 10 mmHg) for about 4 hours to form a red phosphor layer 113 having a film thickness of about 89 nm containing lumogen red.

  A red phosphor forming coating solution 2 is prepared by dissolving a high refractive index resin (refractive index of 1.76 at curing) and lumogen red (0.5 weight percent with respect to the fluororesin) in a solvent. The obtained red phosphor-forming coating solution 2 was applied onto a fluororesin layer with a width of 3 mm on a glass substrate by spin coating. At this time, the spin rate was applied at 2000 rpm. Thereafter, heating and drying were performed in a vacuum oven (200 ° C., 10 mmHg) for about 4 hours to form a red phosphor layer 113 having a film thickness of about 89 nm containing lumogen red.

  The step of forming the above-mentioned fluororesin layer and the step of forming the high refractive index layer were repeated 10 times to produce a red phosphor layer 113 having a thickness of about 1.8 μm.

B: Formation of green phosphor layer 114 First, a green phosphor forming coating solution in which PMMA (polymethyl methacrylate / acrylic resin) and coumarin 6 (0.5 weight percent with respect to fluororesin) are dissolved in a solvent is prepared. create. The obtained green phosphor-forming coating solution was applied to a desired position with a width of 3 mm on a glass substrate by spin coating. At this time, the spin rate was applied at 500 rpm. Thereafter, heating and drying were performed in a vacuum oven (200 ° C., 10 mmHg) for about 4 hours to form a green phosphor layer 114 containing coumarin 6 and having a film thickness of about 1.8 μm.

C: Formation of Transmission Layer 115 First, a blue transmission layer coating solution is prepared by dissolving PMMA (polymethyl methacrylate / acrylic resin) in which TiO ₂ nanoparticles having a particle size of 0.1 to 1 μm are dispersed in a solvent. The obtained blue transmission layer coating solution was applied to a desired position with a width of 3 mm on a glass substrate by spin coating. At this time, the spin rate was applied at 500 rpm. Thereafter, heating and drying were performed in a vacuum oven (200 ° C., 10 mmHg) for about 4 hours to form a transmission layer 115 having a thickness of about 1.8 μm. mHg) and dried by heating for 4 hours to form a transmissive layer 115 containing no phosphor.
Here, TiO ₂ nanoparticles having a particle diameter of 0.1 to 1 μm are dispersed in the transmission layer 115. This is because the blue light transmission direction is brought close to the red phosphor layer 113 and the green phosphor layer 114.

  The phosphor part 2 was produced by the steps according to the above (1. Selection of the sealing substrate 120) and (2. Formation of the red phosphor layer 113, the green phosphor layer 114, and the transmission layer 115).

<Assembly of organic EL element 100>
FIG. 10D is a diagram showing a bonding process between the organic EL portion 1 and the phosphor portion 2.
As shown in FIG. 10D, the organic EL part 1 and the phosphor part 2 produced as described above were aligned using an alignment marker installed outside the display part. The phosphor portion 2 is preliminarily coated with a thermosetting resin, and the organic EL portion 1 and the phosphor portion 2 are brought into close contact with each other through the thermosetting resin and heated at 90 ° C. for 2 hours. Was cured.
This alignment was performed in a dry air environment (water content: −80 ° C.) for the purpose of preventing deterioration of the organic EL due to water.

  Finally, the organic EL element 100 was completed by connecting the terminals formed around the substrate 101 of the organic EL unit 1 to an external power source.

Thus, the organic EL element 100 was manufactured by bonding the organic EL part 1 and the phosphor part 2 together.
The organic EL unit 1 was configured by sequentially laminating an anode 104, an organic layer 109, and a cathode layer 4 on a substrate 101. As the substrate 101, a glass substrate having a thickness of 0.7 mm was used. As the anode 104, a mirror-surface totally reflective electrode containing silver and ITO was used. The organic layer 109 has a multilayer structure including a hole injection layer / hole transport layer / organic light emitting layer / hole prevention layer / electron transport layer / electron injection layer. The organic layer 109 was formed from organic molecules that emit blue light. As the cathode 110, a magnesium-silver transflective electrode was used.

  As the phosphor portion 2, a red phosphor layer 113, a green phosphor layer 114, and a transmission layer 115 each having a width of 3 mm were formed on the sealing substrate 120. A sealing substrate 22 is provided on the phosphor part 2. As the sealing substrate 120, a glass substrate having a thickness of 0.7 mm was used.

  By applying voltage to the anode 104 and the cathode 110, the organic layer 109 emitted blue light. Blue light becomes light having high luminance and high color purity by the microcavity effect, and is transported to the phosphor portion 2. Blue light is converted into red and green by the fluorescent molecules mixed in the red phosphor layer 113 and the green phosphor layer 114.

  In the red phosphor layer 113, since the fluorescent dye lumogen red is dispersed in the photonic crystal having a predetermined density of states, light emission around 603 nm which is the peak wavelength of lumogen red is enhanced. As a result, emitted light with high luminance and high color purity was obtained from the red phosphor layer 113.

[Features of organic EL element 100]
Compared to a conventional organic EL display element in which the color conversion layer 119 is not a photonic crystal, in the organic EL element 100 according to the present invention, the luminance of the red pixel is improved by about 5 to 10%, and a desired voltage is desired by an external power source. The desired good image could be obtained by applying to the striped electrode.

[Configuration of Organic EL Element in Example 2]
Below, the organic EL element of a present Example is demonstrated.
The organic EL device of this example was manufactured as follows.

  Also in Example 2, the organic EL element was configured by bonding the organic EL part 1 and the phosphor part 2 together. The organic EL unit 1 was configured by sequentially laminating an anode 104, an organic layer 109, and a cathode layer 4 on a substrate 101. As the substrate 101, a glass substrate having a thickness of 0.7 mm was used. As the anode 104, a mirror-surface totally reflective electrode containing silver and ITO was used. The organic layer 109 has a multilayer structure including a hole injection layer / hole transport layer / organic light emitting layer / hole prevention layer / electron transport layer / electron injection layer.

  The organic layer 109 was formed from organic molecules that emit blue light. As the cathode 110, a magnesium-silver transflective electrode was used. As the phosphor portion 2, a red phosphor layer 113, a green phosphor layer 114, and a transmission layer 115 each having a width of 3 mm were formed on the sealing substrate 120. A sealing substrate 22 is provided on the phosphor part 2. As the sealing substrate 120, a glass substrate having a thickness of 0.7 mm was used. Since the configuration of each member is the same as that of the organic EL element 100, detailed description is omitted, and only differences from the organic EL element 100 will be described.

  First, the organic EL unit 1 was subjected to the same method as in Example 1 (1. Selection of substrate 101), (2. Formation of anode 104), (3. Formation of organic layer 109), (4. Prepared by steps according to (formation).

Next, the phosphor part 2 was created.
The method for creating the phosphor portion 2 is also the same as that in the first embodiment, but the period of the photonic crystal in the red phosphor layer 113 is different. In Example 2, spin coating was performed at a spin rate of 1900 rpm so that the film thickness of the high refractive index layer and the low refractive index layer of the photonic crystal formed in the red phosphor layer 113 was about 91.5 nm. At this time, the same resin as Example 1 was used for the low refractive index layer and the high refractive index layer, respectively, and the same lumogen red was used for the fluorescent dye. An organic EL element 200 was produced by assembling the organic EL part 1 and the phosphor part 2 thus produced in the same manner as in Example 1.

[Characteristics of Organic EL Element in Example 2]
Compared with a conventional organic EL display element in which the red phosphor layer 113 is not a photonic crystal, the organic EL element in this embodiment has a brightness of the red pixel improved by about 5 to 10%, and a desired voltage is desired by an external power source. The desired good image could be obtained by applying to the striped electrode.
In particular, since the red light of 610 to 630 nm is enhanced, the red color reproduction area is widened and a more vivid image can be obtained.

[Configuration of Organic EL Element in Example 3]
Below, the organic EL element of a present Example is demonstrated.
The organic EL device of this example was manufactured as follows.

  Also in Example 3, the organic EL element was configured by bonding the organic EL part 1 and the phosphor part 2 together. The organic EL unit 1 was configured by sequentially laminating an anode 104, an organic layer 109, and a cathode layer 4 on a substrate 101. As the substrate 101, a glass substrate having a thickness of 0.7 mm was used. As the anode 104, a mirror-surface totally reflective electrode containing silver and ITO was used. The organic layer 109 has a multilayer structure including a hole injection layer / hole transport layer / organic light emitting layer / hole prevention layer / electron transport layer / electron injection layer. The organic layer 109 was formed from organic molecules that emit blue light. As the cathode 110, a magnesium-silver transflective electrode was used.

  As the phosphor portion 2, a red phosphor layer 113, a green phosphor layer 114, and a transmission layer 115 each having a width of 3 mm were formed on the sealing substrate 120. A sealing substrate 22 is provided on the top of the phosphor portion 2. As the sealing substrate 120, a glass substrate having a thickness of 0.7 mm was used. Since the configuration of each member is the same as that of the organic EL element 100, detailed description is omitted, and only differences from the organic EL element 100 will be described.

  First, the organic EL unit 1 was subjected to the same method as in Example 1 (1. Selection of substrate 101), (2. Formation of anode 104), (3. Formation of organic layer 109), (4. Prepared by steps according to (formation).

Next, the phosphor part 2 was created.
In the phosphor part 2 according to the present embodiment, the green phosphor layer 114 also has a structure as a photonic crystal. The creation method is the same as in the first and second embodiments.
The film thickness of the high refractive index layer and the low refractive index layer is about 77 nm, and coumarin 6 is used as the fluorescent dye. Then, the fluorescence of green light having a wavelength of 520 nm can be enhanced in the light extraction direction. The red phosphor layer 113 was produced by the same method as in Example 1.
The organic EL part 1 and the phosphor part 2 thus produced were assembled in the same manner as in Example 1 to produce an organic EL element.

[Characteristics of Organic EL Element in Example 3]
Compared to a conventional organic EL display element in which the green phosphor layer 114 and the red phosphor layer 113 are not photonic crystals, the organic EL element in the present embodiment has a green pixel luminance of approximately 5% and a red pixel luminance of approximately 0.5%. The image was improved by about 5 to 10%, and a desired good image could be obtained by applying a desired voltage to a desired stripe electrode by an external power source. In particular, since green light with high visibility was enhanced, a brighter image could be obtained.

[Configuration of Organic EL Element in Example 4]
Below, the organic EL element of a present Example is demonstrated.
The organic EL device of this example was manufactured as follows.
Also in Example 4, the organic EL element was comprised by bonding the organic EL part 1 and the fluorescent substance part 2 together.

The organic EL unit 1 was configured by sequentially laminating an anode 104, an organic layer 109, and a cathode layer 4 on a substrate 101. As the substrate 101, a glass substrate having a thickness of 0.7 mm was used. As the anode 104, a mirror-surface totally reflective electrode containing silver and ITO was used.
The organic layer 109 has a multilayer structure including a hole injection layer / hole transport layer / organic light emitting layer / hole prevention layer / electron transport layer / electron injection layer. The organic layer 109 was formed from organic molecules that emit blue light. As the cathode 110, a magnesium-silver transflective electrode was used. As the phosphor portion 2, a red phosphor layer 113, a green phosphor layer 114, and a transmission layer 115 each having a width of 3 mm were formed on the sealing substrate 120. A sealing substrate 22 is provided on the top of the phosphor portion 2. As the sealing substrate 120, a glass substrate having a thickness of 0.7 mm was used.

  Since the configuration of each member is the same as that of the organic EL element 100, detailed description is omitted, and only differences from the organic EL element 100 will be described.

  First, the organic EL unit 1 was subjected to the same method as in Example 1 (1. Selection of substrate 101), (2. Formation of anode 104), (3. Formation of organic layer 109), (4. Prepared by steps according to (formation).

Next, the phosphor part 2 was created.
In the phosphor part 2 according to the present embodiment, the production method of the red phosphor layer 113 having a structure as a photonic crystal is different from that of the first to third embodiments. In this example, TiO ₂ nanoparticles having a particle size of about 63 nm are used. A sol-gel method was used as a method for producing the TiO ₂ nanoparticles. The TiO ₂ nanoparticles were dispersed in water, applied to the red phosphor layer 113, dried at room temperature for 3 days, and the TiO ₂ nanoparticles were arranged in a face-centered cubic lattice crystal form by self-assembly.

  Then, after infiltrating a fluororesin containing lumogen red, it was cured by heating and drying in a vacuum oven (200 ° C., 10 mmHg) for about 4 hours. In this way, the red phosphor layer 113 was produced, and the green phosphor layer 114 and the transmissive layer 115 were produced in the same manner as in Example 1, thereby producing the phosphor portion 2. The organic EL part 1 and the phosphor part 2 thus produced were assembled in the same manner as in Example 1 to produce an organic EL element.

[Characteristics of Organic EL Element in Example 4]
Compared to a conventional organic EL display element in which the red phosphor layer 113 is not a photonic crystal, the organic EL element in the present embodiment improves the luminance of the red pixel by about 5% and applies a desired voltage to the desired stripe by an external power source. The desired good image could be obtained by applying to the electrode. In order to produce the red phosphor layer 113 after controlling the particle size in advance, it could be produced more easily than the methods of Examples 1 to 3 which were applied one by one by spin coating.

[Configuration of Organic EL Element in Example 5]
Below, the organic EL element of a present Example is demonstrated.
The organic EL device of this example was manufactured as follows.

  Also in Example 5, the organic EL element was comprised by bonding the organic EL part 1 and the fluorescent substance part 2 together. The organic EL unit 1 was configured by sequentially laminating an anode 104, an organic layer 109, and a cathode layer 4 on a substrate 101. As the substrate 101, a glass substrate having a thickness of 0.7 mm was used. As the anode 104, a mirror-surface totally reflective electrode containing silver and ITO was used. The organic layer 109 has a multilayer structure including a hole injection layer / hole transport layer / organic light emitting layer / hole prevention layer / electron transport layer / electron injection layer. The organic light emitting layer was formed from organic molecules that emit blue light. As the cathode layer 4, a magnesium-silver transflective electrode was used.

  As the phosphor portion 2, a red phosphor layer 113, a green phosphor layer 114, and a transmission layer 115 each having a width of 3 mm were formed on the sealing substrate 120. A sealing substrate 22 is provided on the phosphor part 2. As the sealing substrate 120, a glass substrate having a thickness of 0.7 mm was used. Since the configuration of each member is the same as that of the organic EL element 100, detailed description is omitted, and only differences from the organic EL element 100 will be described.

  First, the organic EL unit 1 was subjected to the same method as in Example 1 (1. Selection of substrate 101), (2. Formation of anode 104), (3. Formation of organic layer 109), (4. Prepared by steps according to (formation).

Next, the phosphor part 2 was created. Since the phosphor portion 2 according to the present embodiment is substantially the same as the phosphor portion 2 according to the fourth embodiment, only different portions will be described. The difference from the phosphor part 2 of Example 4 is that TiO ₂ nanoparticles having a particle diameter of about 65 nm were used. As a result, the color reproduction region can be further expanded by enhancing the light of 620 nm having a longer wavelength than that of Example 4 in which the light of 603 nm is enhanced.

[Characteristics of Organic EL Element in Example 5]
Compared with a conventional organic EL display element in which the color conversion layer 119 is not a photonic crystal, the organic EL element in this embodiment improves the luminance of the red pixel by about 5%, and a desired voltage is applied to the desired stripe shape by an external power source. A desired good image could be obtained by applying to the electrode. In order to produce the color conversion layer 119 after controlling the particle diameter in advance, it could be produced more easily than the methods of Examples 1 to 3 which were applied one by one by spin coating.

[Configuration of Liquid Crystal Display Device 900]
Hereinafter, the liquid crystal display device 900 in this embodiment will be described with reference to FIG.

First, the configuration of the liquid crystal display device (display device) 900 will be described.
FIG. 11 is a schematic diagram partially showing a cross-sectional configuration of the liquid crystal display device of this example.
The liquid crystal display device 900 includes a backlight unit 90, a liquid crystal unit 91, and a phosphor unit 92. As shown in FIG. 11, the backlight unit 90 is configured by arranging blue light emitting diode elements 901 on a plane. The blue light emitting diode element 901 includes a light emitting unit 902 and a light guide unit 903.

The liquid crystal unit 91 is configured by sequentially laminating a polarizing plate 904, a TFT substrate 905, an electrode layer 906, an alignment film 907, a liquid crystal layer 908, and an alignment film 909. As the phosphor portion 92, a red phosphor layer 913, a green phosphor layer 914, and a blue transmission layer 915 were formed on the substrate 910. A sealing substrate 922 is provided on the phosphor portion 92. The red phosphor layer 913, the green phosphor layer 914, and the blue transmissive layer 915 were each formed by the method described in Example 1.
In the phosphor part 92, the configuration of each member is the same as that of the phosphor part 2 in the organic EL element 100, and thus detailed description thereof is omitted.

[Production of liquid crystal display device 900]
Regarding the production of the liquid crystal display device 900, a liquid crystal unit 91 different from the production of the organic EL element 100 will be described. The liquid crystal part 91 was produced as follows. As the TFT substrate 905, an unpolished glass substrate was selected. A scan electrode was formed on an unpolished glass substrate using Al, and the surface of the scan electrode was covered with an alumina film which was an anodic oxide film of Al. Next, a gate insulating (gate SiN) film and an amorphous silicon (a-Si) film were formed so as to cover the scan electrodes.

  Further, an n-type a-Si film, a pixel electrode, and a signal electrode were formed on the a-Si film. Subsequently, a common electrode was provided in the same layer as the pixel electrode and the signal electrode. The pixel electrode and the signal electrode were both parallel to the stripe-shaped common electrode and intersected with the scanning electrode, and a thin film transistor and a metal electrode group were formed on one substrate. Thus, an electric field is applied between the pixel electrode and the common electrode on the substrate, and the direction thereof is substantially parallel to the substrate interface, so that a so-called IPS (In-Plane Switch) type liquid crystal element is formed.

  The electrodes on the substrate are all formed using Al, but the present invention is not limited to this, and any electrode having a low electrical resistance, such as chromium or copper, may be used.

  In this embodiment, the number of pixels is 40 (× 3) × 30, the horizontal direction of the pixel pitch (ie, between the common electrodes) is 80 μm, and the vertical direction (ie, between the gate electrodes) is 240 μm. The width of the common electrode was 12 μm, and the gap between the adjacent common electrodes was narrower than 68 μm, thereby ensuring a high aperture ratio.

  In addition, a polarizing plate 904 is provided on the TFT substrate 905 having a thin film transistor, and a polarizing plate 911 is provided on the substrate 910 opposite to the TFT substrate 905. The polarizing axis of the polarizing plate 904 and the polarizing axis of the polarizing plate 911 were made to be orthogonal to each other.

  In the liquid crystal layer 908, the liquid crystal molecules were arranged so that the major axis directions of the liquid crystal molecules in the vicinity of the upper and lower interfaces were substantially parallel to each other and the angle formed with the applied electric field direction was 15 degrees. In the liquid crystal cell, liquid crystal having positive dielectric anisotropy composed mainly of a compound having three fluoro groups at its ends was sealed. The cell gap was made to be 3.8 μm in a liquid crystal sealed state.

  G1220DU manufactured by Nitto Denko Corporation was used for the polarizing plate 904 and the polarizing plate 911, and the liquid crystal layer was sandwiched between two polarizing plates. Of the polarizing plates 904 and 911, one polarization transmission axis is arranged substantially parallel to the rubbing direction, and the other is arranged so as to be orthogonal to the rubbing direction. The rubbing direction is a major axis direction of liquid crystal molecules in the vicinity of the interface. Thereby, normally closed characteristics were obtained.

  A drive LSI was connected to the panel thus obtained to produce an active matrix drive element.

[Features of the liquid crystal display device 900]
Compared with a conventional liquid crystal display device in which the phosphor layer does not contain metal particles, the luminance is improved by about 5 to 10% in the liquid crystal display device 900, and a desired voltage is applied to a desired pixel electrode by an external power source. Thus, a desired good image could be obtained.

A system 1000 according to the present embodiment will be described with reference to FIG.
The system 1000 is, for example, a smart photon, a tablet personal computer, an electronic book, an electronic album, an electronic textbook, an electronic dictionary, or the like, but is not limited thereto. This time, assuming a digital book, a system 1000 was manufactured using an A5 size organic EL element. A system 1000 includes a light emitting element 1001 (organic EL element 100), a touch panel 1003, a touch panel wiring 1004, a light emitting element wiring 1005, a battery 1006, a central processing unit 1007, a substrate 1011 back cover 1009 on which a recording medium 1008 is mounted, and a surface. Cover 1010.

  At this time, the system 1000 may include a speaker, a camera, or a communication antenna. As shown in FIG. 12, first, a substrate 1011 on which chips necessary for the operation of an electronic book such as a battery 1006, a central processing unit 1007, and a recording medium 1008 are mounted is attached to the back cover 1009. Further thereon, a light emitting element 1001 and a touch panel 1003 are arranged in this order. The touch panel wirings 1004 and 1005 were connected to the substrate 1011 and the front cover 1010 was attached.

[Features of System 1000]
The luminance in the front direction was improved by about 10% as compared with the case where a conventional light emitting element in which no metal particles were contained in the phosphor layer was used. In particular, the present invention uses a photonic crystal structure to particularly increase the brightness in the front direction, so that the viewing direction can be adjusted by hand during use and is suitable for electronic books that are less likely to be viewed from an oblique direction. ing.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to. You may combine the structure of each embodiment suitably.

  W ... Peak, 101, 910, 1011 ... Substrate, 107 ... Light emitting layer, 115 ... Transmission layer, 119 ... Color conversion layer (wavelength conversion layer), 119A ... Light exit surface, 700 ... Organic EL display device (display device), 900 ... Liquid crystal display device (display device), 1001, 1101, 1201, 1301, 1401, 1501 ... Light emitting element

Claims (10)

A substrate,
A light emitting layer provided on the substrate;
A wavelength conversion layer that is provided on the substrate and absorbs light of a first wavelength emitted from the light emitting layer and emits light of a second wavelength;
The wavelength conversion layer includes a photonic crystal,
The light-emitting element, wherein a photon density of states in the light extraction direction of the photonic crystal has a peak in the vicinity of energy corresponding to the second wavelength.   When the second wavelength is λ, the angular frequency corresponding to the peak of the photon state density in the light extraction direction of the photonic crystal is W, and the period of the photonic crystal is a, the dimensionless amount (λ · 2. The light-emitting element according to claim 1, wherein W) / a is in a range of 0.95 or more and 1.05 or less.   The light emitting device according to claim 1, wherein the wavelength conversion layer includes the photonic crystal and a phosphor material dispersed in the photonic crystal.   4. The light emitting device according to claim 3, wherein a wavelength at which the emission spectrum of the phosphor material exhibits a peak substantially coincides with a wavelength at which the photon state density in the light extraction direction of the photonic crystal exhibits a peak. .   5. The light emitting device according to claim 1, wherein the light extraction direction is a direction perpendicular to a light emission surface of the wavelength conversion layer.   The light emitting element according to any one of claims 1 to 5, wherein the light emitting layer emits blue light, and the light of the first wavelength is the blue light.   The light-emitting element according to claim 6, further comprising a transmission layer that transmits light of the first wavelength in a region different from a region where the wavelength conversion layer is formed on the substrate.   The light emitting device according to claim 7, wherein at least a part of the wavelength conversion layer absorbs light of the first wavelength and emits green light.   9. The light emitting device according to claim 7, wherein at least part of the wavelength conversion layer absorbs light of the first wavelength and emits red light.   A display device comprising the light-emitting element according to claim 1.

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