JP2017016792A - Wavelength conversion element, light-emitting device, display device and illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion element capable of obtaining high-intensity light by being irradiated with excitation light from the exterior.SOLUTION: A wavelength conversion element comprises a substrate, and a wavelength conversion layer provided on one surface of the substrate. The wavelength conversion layer comprises: a light emitter layer that has a light emitter for generating light by being irradiated with excitation light; a metal film provided on the one surface of the substrate; and a plurality of wavelength conversion particles at least partially contacted with the metal film. The wavelength conversion particles comprises: metal nanoparticles; a dielectric layer that coats surfaces of the metal nanoparticles; and light emitter contained in the dielectric layer and that generates light by being irradiated with excitation light.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wavelength conversion element, a light emitting device, a display device, and a lighting device.

  As one of light-emitting elements used for display devices and the like, an organic electroluminescence element is conventionally known. Hereinafter, electroluminescence is abbreviated as “EL”. As an example of an organic EL element using wavelength conversion, the following Patent Document 1 includes an organic EL material part and a fluorescent material part, and a part of blue light emitted from the organic EL material part is obtained by fluorescence emission of the fluorescent material part. An “organic EL element” that converts green light or red light and realizes multicolor emission of blue, green, and red is disclosed.

  In an organic EL element using this type of light emission, as means for improving light emission efficiency and obtaining high intensity light, Patent Document 2 below discloses a light emitting layer that emits blue light, and red light that receives blue light. An “organic EL element” including a color conversion layer that is generated, a color conversion layer that receives blue light to generate green light, and a transmission layer that transmits blue light is disclosed. In this organic EL element, the color conversion layer and the transmission layer contain metal nanoparticles that express the surface plasmon phenomenon. According to Patent Document 2, there is an effect that the light conversion is enhanced by containing metal nanoparticles in the color conversion layer.

Japanese Patent Laid-Open No. 3-152897 International Publication No. 2011/104936

  Patent Document 2 discloses a configuration in which a plurality of metal nanoparticles are aggregated. Here, it is described that plasmons may be enhanced by aggregating a plurality of metal nanoparticles. However, even if this configuration is used, there is a problem that a sufficiently high light emission intensity cannot be obtained.

  One aspect of the present invention is made to solve the above-described problem, and an object of the present invention is to provide a wavelength conversion element that can obtain high-intensity light by external excitation light irradiation. . An object of one embodiment of the present invention is to provide a light-emitting device from which high-intensity light can be obtained. An object of one embodiment of the present invention is to provide a display device capable of performing bright display by using the above light-emitting device. An object of one embodiment of the present invention is to provide a bright lighting device by using the above light-emitting device.

  In order to achieve the above object, a wavelength conversion element according to one aspect of the present invention includes a substrate and a wavelength conversion layer provided on one surface of the substrate, and the wavelength conversion layer is irradiated with excitation light. A light emitting layer having a light emitting body that emits light, a metal film provided on the one surface of the substrate, and a plurality of wavelength conversion particles at least partially in contact with the metal film, the wavelength conversion particles Comprises a metal nanoparticle, a dielectric layer covering the surface of the metal nanoparticle, and a light emitter that is contained in the dielectric layer and emits light when irradiated with the excitation light.

  In the wavelength conversion element according to one aspect of the present invention, the light emitter included in the light emitter layer and the light emitter included in the wavelength conversion particle may emit light in the same wavelength range. .

  In the wavelength conversion element according to one aspect of the present invention, the light emitter included in the light emitter layer and the light emitter included in the wavelength conversion particle may emit light in different wavelength ranges. .

  In the wavelength conversion element according to one aspect of the present invention, the distance from the interface on the metal film opposite to the interface with the substrate to the center of the wavelength conversion particle is ½ of the particle diameter of the wavelength conversion particle. It may be the following.

  In the wavelength conversion element according to one aspect of the present invention, the plurality of wavelength conversion particles may be arranged in one layer in a state where a part of the wavelength conversion particles are embedded in the metal film.

  In the wavelength conversion element according to one aspect of the present invention, the phosphor layer may contain metal nanoparticles.

  In the wavelength conversion element according to one aspect of the present invention, the material of the metal nanoparticles includes any one of gold, silver, aluminum, platinum, and copper, and the configuration of the metal nanoparticles includes a sphere or rod made of a single metal. Or a dielectric sphere coated with metal, or an aggregate of two or more particles.

  In the wavelength conversion element according to one aspect of the present invention, an area occupation ratio of the plurality of wavelength conversion particles per unit area of the metal film may be 0.3 or more and 0.9 or less.

  The wavelength conversion element according to one aspect of the present invention may include a wavelength selection unit that reflects or transmits the excitation light and transmits or reflects the light.

  In the wavelength conversion element according to one aspect of the present invention, the metal film may include a first region and a second region in which the transmittance of the excitation light is larger than the first region. Good. In this case, when the metal film is viewed from the normal direction, the region where the wavelength conversion particles exist overlaps the first region, and the region where the wavelength conversion particles do not exist overlaps the second region. May be.

  A light emitting device according to one aspect of the present invention includes the excitation light source unit that emits the excitation light, and the wavelength conversion element according to one aspect of the present invention.

  In the light emitting device according to one aspect of the present invention, the excitation light is incident from a surface of the wavelength conversion layer on the metal film side, and the light is from a surface of the wavelength conversion layer opposite to the metal film. The structure which injects may be sufficient.

  In the light emitting device according to one aspect of the present invention, the excitation light is incident from a surface of the wavelength conversion layer opposite to the metal film, and the light is opposite to the metal film of the wavelength conversion layer. The structure which injects from the surface may be sufficient.

  A display device according to one aspect of the present invention includes the light-emitting device according to one aspect of the present invention.

  An illumination device according to one aspect of the present invention includes the light-emitting device according to one aspect of the present invention.

  According to one aspect of the present invention, it is possible to realize a wavelength conversion element that can obtain high intensity light by irradiation with excitation light from the outside. According to one aspect of the present invention, a light emitting device capable of obtaining high intensity light can be realized. According to one embodiment of the present invention, a display device using a light emitting device capable of obtaining high intensity light can be realized. According to one embodiment of the present invention, an illumination device using a light emitting device capable of obtaining high intensity light can be realized.

It is sectional drawing of the light-emitting device of 1st Embodiment. (A) It is a figure which shows the absorption and emission spectrum of rumogen red, (B) It is a figure which shows the absorption and emission spectrum of coumarin 6. (A) It is a figure for demonstrating the effect | action of the metal nanoparticle in a prior art, (B) It is a figure for demonstrating the effect | action of the metal nanoparticle in this embodiment. FIG. 2 shows a simulation model of emission intensity in the prior art, (A) a plan view of a wavelength conversion unit, and (B) a sectional view taken along line A-A ′ of (A). FIG. 2 shows a simulation model of light emission intensity in the present embodiment, (A) a plan view of a wavelength conversion unit, and (B) a cross-sectional view taken along line B-B ′ of (A). It is a graph which shows the relationship between the metal film thickness and emission peak intensity when the area occupation rate of particle | grains is 0.3. It is a graph which shows the relationship between the metal film thickness and emission peak intensity when the area occupation rate of a particle | grain is 0.4. It is a graph which shows the relationship between the metal film thickness and emission peak intensity when the area occupation rate of a particle | grain is 0.9. It is a graph which shows the relationship between excitation light intensity, the number of light-emitting body particles, and a metal film thickness. It is a graph which shows the relationship between the light extraction efficiency from luminous body particle | grains, the light emission peak intensity, and a metal film thickness. It is a graph which shows the relationship between the area occupation rate of the wavelength conversion particle per unit area of a metal film, and luminescence peak intensity. It is a graph which shows the relationship between the area occupation rate of the wavelength conversion particle | grains per unit area of a metal film, and emission peak intensity when changing a metal film thickness. (A)-(E) It is process sectional drawing which shows the 1st manufacturing method of a wavelength conversion part. (A)-(D) It is process top view which shows the 1st manufacturing method of a wavelength conversion part. It is a figure which shows the manufacturing method of (A)-(D) wavelength conversion particle | grains. (A)-(D) It is process sectional drawing which shows the 2nd manufacturing method of a wavelength conversion part. (A)-(D) It is process sectional drawing which shows the 3rd manufacturing method of a wavelength conversion part. It is sectional drawing of the light-emitting device of 2nd Embodiment. It is a graph which shows the relationship between the area occupation rate of the wavelength conversion particle per unit area of a metal film, and luminescence peak intensity. It is a graph which shows the relationship between the area occupation rate of the wavelength conversion particle | grains per unit area of a metal film, and emission peak intensity when changing a metal film thickness. It is process sectional drawing which shows the manufacturing method of (A)-(D) wavelength conversion board | substrates. It is process top view which shows the manufacturing method of (A)-(D) wavelength conversion board | substrates. It is a figure which shows the absorption and emission spectrum of coumarin 6 and rhodamine 101. It is sectional drawing of the light-emitting device of 3rd Embodiment. (A) It is a figure which shows the scattering intensity spectrum of a silver covering silica sphere, and the luminescence spectrum of rumogen red, (B) It is a figure which shows the scattering intensity spectrum of a silver covering silica sphere, and the emission spectrum of coumarin 6. It is a figure which shows the absorption and scattering spectrum of a silver covering silica sphere. It is a perspective view of the illuminating device of 4th Embodiment. It is sectional drawing which follows the C-C 'line of FIG. (A)-(C) It is a figure for demonstrating the usage method of an illuminating device. It is a perspective view of the illuminating device of 5th Embodiment. It is sectional drawing which shows the modification of wavelength conversion particle.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a cross-sectional view showing the light emitting device of the first embodiment.
In the following drawings, in order to make each component easy to see, the scale of the size may be varied depending on the component.

[overall structure]
As shown in FIG. 1, the light emitting device 1 of this embodiment includes an excitation light source unit 2 and a wavelength conversion unit 3. The excitation light source unit 2 emits excitation light for exciting the luminescent particles 14R and 14G of the wavelength conversion unit 3. The excitation light source unit 2 is provided to face the first surface 3a (the lower surface in FIG. 1) of the wavelength conversion unit 3. The wavelength conversion unit 3 includes phosphor particles 14R and 14G that generate light when irradiated with excitation light. In the wavelength converter 3, the luminescent particles 14R and 14G absorb excitation light and emit light in a wavelength region (color) different from the excitation light. In other words, the wavelength range (color) of the excitation light emitted from the excitation light source unit 2 is converted by the wavelength conversion unit 3. The excitation light source unit 2 includes a first substrate 5, a light emitting unit 6, and a second substrate 7. The wavelength conversion unit 3 includes a third substrate 8, a wavelength conversion layer 4, and a fourth substrate 12. The wavelength conversion layer 4 includes a metal film 9, a plurality of wavelength conversion particles 10R and 10G, and light emitting layers 11R and 11G.
Detailed configurations of the excitation light source unit 2 and the wavelength conversion unit 3 will be described later.

  The light emitting device 1 of the present embodiment is assumed to be used as a display device. Therefore, the light emitting device 1 has a plurality of pixels arranged in a matrix. The pixel is composed of a red sub-pixel 15R that displays red, a green sub-pixel 15G that displays green, and a blue sub-pixel 15B that displays blue. In FIG. 1, only one pixel composed of the red sub-pixel 15R, the green sub-pixel 15G, and the blue sub-pixel 15B among the plurality of pixels is shown as a representative.

[Excitation light source]
As the first substrate 5, 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) A metal substrate containing iron (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 is anodized on the surface. And a substrate subjected to insulation treatment by the above method. However, the substrates that can be used in this embodiment are not limited to these substrates. For example, when the material of the substrate is glass, deformation is not caused even by a high-temperature process and moisture is not transmitted, which is preferable in that deterioration of the organic EL element can be suppressed. As the second substrate 7, a substrate similar to the first substrate 5 can be used.

  Although not shown in FIG. 1, a TFT circuit is provided on the surface of the first substrate 5 on the side facing the second substrate 7. The TFT circuit functions as a switching element and a driving element of the excitation light source unit. As a specific configuration of the TFT circuit, a known TFT circuit can be used.

  The excitation light source unit 2 includes a cathode 17, an anode 18, and an organic light emitting layer 19 sandwiched between the cathode 17 and the anode 18. The organic light emitting layer 19 has a configuration in which, for example, an electron injection layer 20, an electron transport layer 21, a hole blocking layer 22, a light emitter layer 23, a hole transport layer 24, and a hole injection layer 25 are laminated in this order from the cathode 17 side. Have The light emitter layer 23 emits blue light.

The organic light emitting layer 19 is not limited to the configuration of the present embodiment, and may be a single layer structure of the light emitter layer 23 or a multilayer structure including the light emitter layer 23, the hole transport layer 24, the electron transport layer 21, and the like. . For example, although the following nine types of structures are mentioned, this invention is not limited by these.
(1) Light emitter layer
(2) Light emitter layer / hole transport layer (3) Electron transport layer / light emitter layer (4) Electron transport layer / light emitter layer / hole transport layer (5) Electron transport layer / light emitter layer / hole transport Layer / hole injection layer (6) electron injection layer / electron transport layer / light emitter layer / hole transport layer / hole injection layer (7) electron transport layer / hole prevention layer / light emitter layer / hole transport layer / Hole injection layer (8) electron injection layer / electron transport layer / hole prevention layer / light emitter layer / hole transport layer / hole injection layer (9) electron injection layer / electron transport layer / hole prevention layer / Light emitter layer / electron prevention layer / hole transport layer / hole injection layer Here, light emitter layer, hole injection layer, hole transport layer, hole prevention layer, electron prevention layer, electron transport layer and electron injection layer Each of these layers may have a single layer structure or a multilayer structure.

  The excitation light source unit 2 may have a structure that exhibits a microcavity effect. In order to exhibit the microcavity effect, for example, it is desirable to set the thickness of the organic light emitting layer 19 so as to match the wavelength of light to be enhanced. In the organic EL element, the organic light emitting layer 19 is sandwiched between a pair of electrodes. Of these, one electrode is made of a mirror surface total reflection material, the other electrode is made of a semi-transmission material such as a dielectric mirror, and the thickness of the organic light emitting layer 19 is formed in accordance with the wavelength range of blue light, for example. As a result, the light emitted from the light emitter layer 23 repeats multiple reflections between the pair of electrodes and resonates to be output with a desired wavelength. Also, with this structure, the light from the light emitter layer 23 can be given directivity, and the light emission efficiency at the front can be increased. In this way, light can be supplied to the wavelength conversion unit 3 more efficiently, and the front luminance can be increased. In addition, the emission spectrum can be adjusted by the interference effect. Accordingly, it is possible to control to a spectrum that can excite the red light emitter and the green light emitter more effectively, and to improve the color purity of the blue sub-pixel 15B.

  The luminous body layer 23 may be composed of only an organic light emitting material exemplified below, or may be composed of a combination of a light emitting dopant and a host material, and optionally includes a hole transport material, an electron transport material, Additives (donor, acceptor, etc.) may be included, and these materials may be dispersed in a polymer material (binding resin) or an inorganic material. From the viewpoint of luminous efficiency and luminous lifetime, those in which a luminescent dopant is dispersed in a host material are preferable.

  Examples of the organic light emitting material include known light emitting materials for organic EL. This type of light-emitting material is 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.

Specific compounds are exemplified below, but the present 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 luminescent 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 that is optionally contained in the light-emitting layer 23 include known dopant materials for organic EL elements. Examples of such dopant materials include luminescent materials such as styryl derivatives, bis [(4,6-difluorophenyl) -pyridinato-N, C2 ′] picolinate iridium (III) (FIrpic), bis (4 ′, 6 And phosphorescent organometallic complexes such as' -difluorophenylpolydinato) tetrakis (1-pyrazoyl) borateiridium (III) (FIr ₆ ).

  Examples of the host material when using the dopant include known host materials for organic EL elements. 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. The electron injection layer 20 and the electron transport layer 21 are used for the purpose of more efficiently injecting and transporting electrons from the cathode 17 to the light emitting layer 23. A hole injection layer 25 and a hole transport layer 24 are used for the purpose of efficiently injecting and transporting holes from the anode 18 to the light emitting layer 23. These layers may be composed only of the charge injection / transport materials exemplified below, and may optionally contain additives (donors, acceptors, etc.), and these materials are polymer materials (conjugates). Wear resin) or a structure dispersed in an inorganic material.

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

Examples of materials for the hole injection layer 25 and the hole transport layer 24 include oxides such as vanadium oxide (V ₂ O ₅ ) and molybdenum oxide (MoO ₂ ), inorganic p-type semiconductor materials, porphyrin compounds, N, N '-Bis (3-methylphenyl) -N, N'-bis (phenyl) -benzidine (TPD), N, N'-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (NPD) Low molecular weight materials such as aromatic tertiary amine compounds, hydrazone compounds, quinacridone compounds, styrylamine compounds, etc., polyaniline (PANI), polyaniline-camphor sulfonic acid (PANI-CSA), 3,4-polyethylenedioxythiophene / Polystyrene sulfonate (PEDOT / PSS), poly (triphenylamine) derivative (Poly-TPD), polyvinyl carbonate Examples thereof include polymer materials such as rubazole (PVCz), poly (p-phenylene vinylene) (PPV), and poly (p-naphthalene vinylene) (PNV).

  From the viewpoint of more efficient injection and transport of holes from the anode 18, the material of the hole injection layer 25 has the highest occupied molecular orbital (HOMO) energy level than the material of the hole transport layer 24. It is preferable to use a low material. The material of the hole transport layer 24 preferably has a higher hole mobility than the material of the hole injection layer 25.

  In order to further improve the hole injecting property and transporting property, the material is preferably doped with an acceptor. As an acceptor, the well-known acceptor material for organic EL elements 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, POC ₁₃ , 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 effectively increase the carrier concentration.

Examples of materials for the electron injection layer 20 and the electron transport layer 21 include inorganic materials that are n-type semiconductors, oxadiazole derivatives, triazole derivatives, thiopyrazine dioxide derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, diphenoquinone derivatives, Low molecular materials such as fluorenone derivatives and benzodifuran derivatives; polymer materials such as poly (oxadiazole) (Poly-OXZ) and polystyrene derivatives (PSS) are used. In particular, examples of the material for the electron injection layer 20 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 performing electron injection / transport from the cathode 17 more efficiently, the material of the electron injection layer 20 is a material having a higher energy level of the lowest unoccupied molecular orbital (LUMO) than the material of the electron transport layer 21. The material for the electron transport layer 21 is preferably a material having a higher electron mobility than the material for the electron injection layer 20.

  In order to further improve the electron injection efficiency and the electron transport property, the material of the electron injection layer 20 and the electron transport layer 21 is preferably doped with a donor. As a donor, the well-known donor material for organic EL elements 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.), triphenyldia Compounds having an aromatic tertiary amine skeleton such as N (N, N′-di- (4-methyl-phenyl) -N, N′-diphenyl-1,4-phenylenediamine), phenanthrene, pyrene, perylene Organic materials such as condensed polycyclic compounds such as anthracene, tetracene and pentacene (however, the condensed polycyclic compounds may have a substituent), TTF (tetrathiafulvalene), dibenzofuran, phenothiazine and carbazole. Among these, compounds having an aromatic tertiary amine in the skeleton, condensed polycyclic compounds, and alkali metals are more preferable because the carrier concentration can be effectively increased.

  In the case of this embodiment, the light emitter layer 23 emits light in the blue wavelength region of 380 to 480 nm. Specifically, FIrPic [bis (3,5-difluoro-2- (2-pyridylphenyl- (2-carboxypyridyl) iridium (III)]) having a central emission wavelength in the vicinity of 450 nm is used as the light-emitting material.

  The organic light emitting layer 19 including the hole injection layer 25, the hole transport layer 24, the light emitter layer 23, the electron transport layer 21, the electron injection layer 20, and the like was prepared by dissolving and dispersing the materials of these layers in a solvent. It can form using the coating liquid for light emitting layer formation. At this time, 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, printing method such as micro gravure coating method, etc. A known wet process, a resistance heating vapor deposition method, an electron beam (EB) vapor deposition method, a molecular beam epitaxy (MBE) method, a sputtering method, an organic vapor deposition (OVPD) method, or the like, A laser transfer method or the like is used. When the organic light emitting layer 19 is formed by a wet process, the light emitting layer forming coating solution may contain additives for adjusting the physical properties of the coating solution such as a leveling agent and a viscosity adjusting agent.

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

  Of the cathode 17 and the anode 18, the electrode from which light is extracted must transmit at least part of the light emitted from the light emitter layer 23. In the present embodiment, light emitted from the light emitter layer 23 is extracted from the anode 18 side. Note that the order of stacking may be reversed from that of the present embodiment, and light may be extracted from the cathode 17 and the anode 18 may reflect the light.

As an electrode material for forming the cathode 17 and the anode 18, known electrode materials can be used. As an electrode material for forming the anode 18, gold (Au), platinum (Pt), nickel (Ni) having a work function of 4.5 eV or more from the viewpoint of more efficiently injecting holes into the organic light emitting layer 19. ) And an oxide containing indium (In) and tin (Sn) (ITO), tin (Sn) oxide (SnO ₂ ), indium (In) and zinc (Zn) ( IZO) and the like are listed as transparent electrode materials. The electrode material for forming the cathode 17 is lithium (Li), calcium (Ca), cerium (Ce) having a work function of 4.5 eV or less from the viewpoint of more efficient electron injection into the organic light emitting layer 19. And metals such as barium (Ba) and aluminum (Al), or alloys such as Mg: Ag alloys and Li: Al alloys containing these metals.

The sealing layer 27 seals the side surface of the organic light emitting layer 19. The sealing layer 27 can be formed using any insulating material. The insulating material may be an organic material or an inorganic material.
The excitation light source unit 2 is not necessarily limited to the OLED, and may be configured by an LED, a fluorescent lamp, or the like.

[Wavelength converter]
As shown in FIG. 1, the wavelength conversion unit 3 includes a third substrate 8, a wavelength conversion layer 4, and a fourth substrate 12. The wavelength conversion layer 4 includes a metal film 9, a plurality of wavelength conversion particles 10R and 10G, light emitter layers 11R and 11G, a light transmission layer 29, a fourth substrate 12, and a black matrix 30. . The metal film 9, the plurality of wavelength conversion particles 10 </ b> R and 10 </ b> G, the light emitter layers 11 </ b> R and 11 </ b> G, and the light transmission layer 29 are sandwiched between the third substrate 8 and the fourth substrate 12. The third substrate 8 is disposed so as to face the excitation light source unit 2. The fourth substrate 12 is disposed on the side opposite to the excitation light source unit 2.

  As the third substrate 8, for example, a substrate made of a material having a high light transmittance such as an inorganic material substrate made of glass, quartz or the like, a plastic substrate containing polyethylene terephthalate, polycarbazole, polyimide, or the like is preferably used. However, the substrate used in this embodiment is not limited to these substrates. Also for the fourth substrate 12, a substrate made of the same material as the third substrate 8 can be used.

  The metal film 9 is provided on the first surface 11a (the surface on the side where the third substrate 8 is provided) of the light emitting layers 11R and 11G. Of the three sub-pixels, the metal film 9 is provided in the red sub-pixel 15R and the green sub-pixel 15G, and is not provided in the blue sub-pixel 15B. As the metal film 9, it is desirable to use gold, silver, aluminum or the like, and in this embodiment, silver is used. The film thickness of the metal film 9 is desirably in the range of 1 nm to 200 nm. In the case of the present embodiment, the metal film 9 needs to transmit the excitation light emitted from the excitation light source unit 2 toward the light emitter layers 11R and 11G. Therefore, the film thickness of the metal film 9 needs to be thin to some extent, for example, 45 nm.

  The wavelength conversion layer 4 includes two light emitter layers, a light emitter layer 11R and a light emitter layer 11G, and one light transmission layer 29. The light emitter layer 11R is provided corresponding to the red sub-pixel 15R. The light emitter layer 11G is provided corresponding to the green sub-pixel 15G. The light transmission layer 29 is provided corresponding to the blue subpixel 15B. The light transmission layer 29 has a function of adjusting the light distribution state of the transmitted blue light while transmitting the blue light. A black matrix 30 is formed between the two adjacent light emitter layers 11R and 11G and between the light emitter layers 11R and 11G and the light transmission layer 29. Note that the light emitter layer referred to in the present embodiment does not necessarily have to be composed of the light emitter material, and at least a part of the light emitter layer contains the light emitter material. That's fine. Further, as the light emitting material, a phosphor material or a phosphor material may be used.

  In the light emitting device 1 of the present embodiment, the blue light emitted from the excitation light source unit 2 enters the wavelength conversion unit 3. The blue light incident on the light emitter layer 11R is converted into red light and emitted. The blue light incident on the light emitter layer 11G is converted into green light and emitted. The blue light incident on the light transmission layer 29 is adjusted in the light distribution state and emitted as blue light.

  The phosphor layer 11R and the phosphor layer 11G may be composed of only the phosphor material exemplified below, and may optionally contain additives and the like, and these materials are polymer materials (binding resin). ) Or a structure dispersed in an inorganic material. Further, the phosphor material is not limited to the phosphor material, and may be a phosphor material or the like.

  The phosphor layer 11R and the phosphor layer 11G of the present embodiment have a configuration in which a plurality of phosphor particles 14R and 14G are dispersed in a transparent resin. The luminescent particles 14R and 14G generate light when irradiated with excitation light. Here, the wavelength range of the excitation light corresponds to the blue range, and the wavelength range of the light emitted by the irradiation of the excitation light corresponds to the color gamut of each individual sub-pixel. That is, the luminescent particles 14R used in the luminescent layer 11R of the red sub-pixel 15R generate red light when irradiated with excitation light in the blue color. The luminescent particles 14G used in the luminescent layer 11G of the green subpixel 15G generate green light when irradiated with excitation light in the blue color. The thickness of the light emitter layers 11R and 11G is, for example, 7 μm.

  A known phosphor material can be used for the phosphor particles 14R and 14G of the present embodiment. Such phosphor materials are classified into organic phosphor materials, inorganic phosphor materials, organic phosphor materials, inorganic phosphor materials and the like. Although these specific compounds are illustrated below, this invention is not limited to these materials.

  As an organic fluorescent material, as a fluorescent dye that converts blue excitation light into green light, 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'-benzimidazolyl) -7-N, N-diethylaminocoumarin (coumarin 7) ), Naphthalimide dyes: basic yellow 51, solvent yellow 11, solvent yellow 116, fluorescein dye, and the like.

  As fluorescent dyes that convert blue excitation light into red light, 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, basic violet 11, sulfo Rhodamine 101 etc. are mentioned.

Inorganic phosphor materials include (BaMg) Al ₁₆ O ₂₇ : Eu ²⁺ , Mn ²⁺ , Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ , (SrBa) Al as phosphors that convert blue excitation light into green light. 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 ) 3Cl: Eu ²⁺ , Sr ₂ Si ₃ O ₈ -2SrCl ₂ : Eu ²⁺ , Zr ₂ SiO ₄ , MgAl ₁₁ O 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.

As phosphors that convert blue excitation light into red light, Y ₂ O ₂ S: Eu ³⁺ , YA ₁ O 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.

Host materials that convert blue excitation light into red light and green light as organic phosphor materials include organometallic complexes, oxadiazole compounds, phenanthroline compounds, triazine compounds, triazole compounds, and spirofluorenes It is desirable to use one or more selected from the group consisting of system compounds.
Phosphorescent dopants that convert blue excitation light into red and green light include bisthienylpyridine acetylacetonate iridium, bis (benzothienylpyridine) acetylacetonate iridium, bis (2-phenylbenzothiazole) acetylacetonate iridium, It is desirable to use one or more selected from the group consisting of bis (1-phenylisoquinoline) iridium acetylacetonate, tris (1-phenylisoquinoline) iridium, and tris (2-phenylpyridine) iridium.

Examples of inorganic phosphor materials that convert blue excitation light into red light and green light include CaS: Eu ²⁺ , Mn ²⁺ , SrS: Eu ²⁺ , (Zn, Cd) S: Ag; M g ₄ GeO _5.5 F: MN ⁴⁺ , ZnSe: Cu, or ZnSeS: Cu, Cl and ZnS: Cu ⁺ , SrGa ₂ S ₄ : Eu ²⁺ , YAG: Ce ³⁺ , BaSrGa ₄ S ₇ : Eu are preferably used.

  In addition, the light emitter layer 11R and the light emitter layer 11G can be formed using a light emitter layer forming coating solution in which the light emitter material and the resin material are dissolved and dispersed in a solvent. At this time, 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, printing method such as micro gravure coating method, etc. A known wet process, a resistance heating vapor deposition method, an electron beam (EB) vapor deposition method, a molecular beam epitaxy (MBE) method, a sputtering method, an organic vapor deposition (OVPD) method, or the like, A laser transfer method or the like is used.

  A material such as PMMA (polymethyl methacrylate), PVA (polyvinyl alcohol), or the like is used for the transparent resin constituting the light emitter layer 11R and the light emitter layer 11G. For example, lumogen red is used for the phosphor particles 14R used in the phosphor layer 11R of the red sub-pixel 15R. The absorption / emission spectrum of lumogen red is shown in FIG. From this, it can be seen that Lumogen Red has an absorption maximum wavelength of 570 nm and an emission maximum wavelength of 600 nm. For example, coumarin 6 is used for the phosphor particles 14G used in the phosphor layer 11G of the green sub-pixel 15G. The absorption / emission spectrum of coumarin 6 is shown in FIG. From this, it can be seen that the absorption maximum wavelength of coumarin 6 is 450 nm, and the emission maximum wavelength is 500 nm.

  The plurality of wavelength conversion particles 10 </ b> R and 10 </ b> G are provided in a form in which a part of the lower side of each wavelength conversion particle 10 </ b> R and 10 </ b> G is embedded in the metal film 9. In the case of this embodiment, the particle diameters of the wavelength conversion particles 10 </ b> R and 10 </ b> G are larger than the film thickness of the metal film 9. The plurality of wavelength conversion particles 10R and 10G are basically arranged in a single layer without being stacked. However, it is ideal that the plurality of wavelength conversion particles 10R and 10G are perfectly arranged in one layer, but a part of the plurality of wavelength conversion particles 10R and 10G is aggregated, and the stacked portions are slightly. May be present. The wavelength conversion particles 10R and 10G are substantially spherical, and the diameter of the wavelength conversion particles 10R and 10G is preferably in the range of 0.01 μm to 1 μm (10 nm to 1000 nm), for example, 0.01 μm to 0.1 μm (10 nm to 100 nm). ) Is more preferable. In the present embodiment, the diameter of the wavelength conversion particles 10R and 10G is, for example, about 70 nm. The wavelength conversion particles 10R and 10G include metal nanoparticles 32, a dielectric layer 33 that covers the surface of the metal nanoparticles 32, and a plurality of phosphor particles 14R and 14G contained in the dielectric layer 33. Yes.

  Specific examples of the metal nanoparticles 32 include the following, but are not limited thereto. The metal nanoparticles 32 may be anything that can induce a surface plasmon phenomenon. The “surface plasmon phenomenon” refers to a state where electrons in the metal nanoparticles 32 resonate with the electric field of light. The surface plasmon phenomenon is caused when light is incident from a material with a high refractive index to a material with a low refractive index below the critical angle and totally reflected and oozes into a material with a low refractive index, or the diameter is smaller than the wavelength of light. It is also excited when electrons such as metal particles resonate with near-field light (evanescent light) in the case of light entering from the opening when light enters the opening.

Furthermore, there are two principles for increasing the light intensity of the luminescent particles due to surface plasmons, and can be simply explained as follows. First, when the excitation light is irradiated to the metal nanoparticles, an enhanced electric field is formed in the vicinity of the metal nanoparticles, and this enhanced electric field acts on the phosphor particles existing in the vicinity of the metal nanoparticles (dipole resonance). ), High intensity light can be obtained from the phosphor particles. In order to enhance this effect, the plasmon resonance wavelength needs to exist within the absorption wavelength range of the phosphor particles.
Second, when the phosphor particles are irradiated with the excitation light, if the metal nanoparticles are present in the vicinity of the phosphor particles, the energy transferred by the phosphor particles is transferred to the metal nanoparticles, thereby the metal nanoparticles. Therefore, high intensity light can be obtained. In order to enhance this effect, the plasmon resonance wavelength needs to exist within the emission wavelength region of the phosphor particles.

  As the metal nanoparticles 32, for example, Au, Ag, Al, Pt, Cu, Mn, Mg, Ca, Li, Yb, Eu, Sr, Ba, Na, etc., and two or more kinds of these metals are used. An alloy selected and formed as appropriate, for example, Mg: Ag, Al: Li, Al: Ca, Mg: Li is used. Among the above, as the metal nanoparticle 32, it is desirable to use gold, silver, aluminum or the like, as in the case of the metal film 9. In this embodiment, silver is used. Silver is suitable for the material of the metal nanoparticles 32 because it can efficiently absorb blue excitation light. The shape of the metal nanoparticles 32 is preferably spherical, rod-shaped, a shape in which a dielectric sphere is covered with a metal, two or more aggregates, and the like in this embodiment. The size of the metal nanoparticle 32 needs to be a size at which plasmon resonance is expressed by light in the visible range. The diameter of the metal nanoparticles 32 is preferably in the range of 0.01 μm to 1 μm (10 nm to 1000 nm), and more preferably in the range of 0.01 μm to 0.1 μm (10 nm to 100 nm). In the present embodiment, the diameter of the metal nanoparticles 32 is, for example, 60 nm.

  The dielectric layer 33 covers the surface of the spherical metal nanoparticle 32 with a substantially constant thickness. The dielectric layer 33 is preferably a transparent material such as silicon oxide or titanium oxide. In this embodiment, silicon oxide is used. The thickness of the dielectric layer 33 corresponds to the gap between the metal nanoparticles 32 and the metal film 9. Therefore, controlling the thickness of the dielectric layer 33 is equivalent to controlling the gap between the metal nanoparticles 32 and the metal film 9. In order to generate strong plasmon resonance between the metal nanoparticles 32 and the metal film 9, the gap between the metal nanoparticles 32 and the metal film 9 needs to be equal to or less than the diameter of the metal nanoparticles 32. In the present embodiment, since the diameter of the metal nanoparticles 32 is 60 nm, the thickness of the dielectric layer 33 (the gap between the metal nanoparticles 32 and the metal film 9) is preferably 60 nm or less. Therefore, in the present embodiment, the thickness of the dielectric layer 33 is set to 5 nm, for example. Thus, the plasmon resonance wavelength is about 450 nm.

  In the present embodiment, a plurality of phosphor particles 14R and 14G are dispersed in the dielectric layer 33. The phosphor particles 14R and 14G contained in the dielectric layer 33 are the same as the phosphor particles 14R and 14G contained in the phosphor layers 11R and 11G. That is, the phosphor particles 14R in the dielectric layer 33 of the wavelength conversion particles 10R present in the red sub-pixel 15R and the phosphor particles 14R contained in the phosphor layer 11R are irradiated with the excitation light in the blue region in the red region. Produces light. The phosphor particles 14G in the dielectric layer 33 of the wavelength conversion particles 10G existing in the green sub-pixel 15G and the phosphor particles 14G contained in the phosphor layer 11G are irradiated with light in the green region by irradiation with excitation light in the blue region. Produce.

  In the red sub-pixel 15R of the present embodiment, lumogen red (absorption maximum wavelength 570 nm / light emission maximum wavelength: 600 nm) is used as the phosphor particles 14R. In the green subpixel 15G, coumarin 6 (absorption maximum wavelength 450 nm / light emission maximum wavelength: 500 nm) is used as the luminescent particles 14G.

The light conversion principle of the wavelength conversion particles 10R and 10G will be described using the absorption / emission spectra of Lumogen Red and Coumarin 6 in FIGS. 2 (A) and 2 (B).
First, when the wavelength conversion particles 10 </ b> R and 10 </ b> G are irradiated with blue excitation light (emission maximum wavelength 450 nm), an enhanced electric field is formed in the vicinity of the metal nanoparticles 32. At this time, the enhanced electric field formed is strongest at the plasmon resonance wavelength, and the wavelength corresponds to about 450 nm. The formed enhanced electric field acts on lumogen red or coumarin 6 at an absorption wavelength of 450 nm, so that light having an emission maximum wavelength of 600 nm or 500 nm is emitted from lumogen red or coumarin 6.
Further, the blue region excitation light (light emission maximum wavelength 450 nm) that could not be absorbed by the wavelength conversion particles 10R and 10G is absorbed by the luminogen red or coumarin 6 of the light emitting layers 11R and 11G inside the red sub-pixels 15R and 15B. , Light having an emission maximum wavelength of 600 nm or 500 nm is emitted. That is, light with high intensity, which is the sum of the light emitted from the wavelength conversion particles 10R and 10G and the light emitted from the light emitter particles 14R and 14G inside the light emitter layer, is emitted to the outside.

  However, the emission wavelength region of the phosphor particles 14R and 14G in the dielectric layer 33 of the wavelength conversion particles 10R and 10G and the emission wavelength region of the phosphor particles 14R and 14G in the phosphor layers 11R and 11G coincide with each other. It does not have to be. That is, the luminescent material in the dielectric layer 33 of the wavelength converting particles 10R and 10G may be different from the luminescent material in the luminescent layers 11R and 11G.

  The light transmission layer 29 is provided corresponding to the blue subpixel 15B. The blue sub-pixel 15B is provided with a light transmission layer 29 because the blue light emitted from the excitation light source unit 2 may be transmitted without wavelength conversion. For the light transmission layer 29, for example, a transparent resin material such as PMMA or PVA is used.

  The black matrix 30 is provided in a lattice shape so as to partition adjacent sub-pixels. A known light shielding material is used for the black matrix 30. The dimension of the sub-pixel is, for example, 51 μm × 13 μm. In this case, the resolution as the display device is 440 ppi.

In this embodiment, although it is not the structure containing a wavelength selection part (not shown), you may provide the wavelength selection part in the single side | surface or both surfaces of the wavelength conversion layer 4. FIG. For example, a dichroic filter that transmits blue light and reflects light outside the blue region is reflected on the third substrate 8 side of the wavelength conversion layer 4, and blue light is reflected on the fourth substrate 12 side. In addition, each of the dichroic mirrors that transmit light outside the blue range can be used as the wavelength selection unit.
At this time, since the light in the blue region emitted from the excitation light source unit 2 has a longer optical path length inside the wavelength conversion layer 4 than when there is no wavelength selection unit, the phosphor particles efficiently absorb and emit light. be able to. The emitted light is transmitted through the wavelength selection section on the fourth substrate 12 side of the wavelength conversion layer 4 and emitted.

Hereinafter, the electric field enhancing action by the plasmon resonance of the metal nanoparticles 32 will be described with reference to FIGS.
FIG. 3A is a diagram for explaining the action of the metal nanoparticles 32 in the conventional structure. FIG. 3B is a diagram for explaining the operation of the metal nanoparticles 32 in the present embodiment.

  As shown in FIG. 3A, in the conventional structure, two metal nanoparticles 32 having a diameter D1 (D1 is 60 nm, for example) are paired and exist in the form of a metal nanoparticle pair. When the excitation light Lr is incident on the metal nanoparticle pair, strong absorption occurs in the gap region having a width S1 (S1 is, for example, 5 nm) between the metal nanoparticles, and an accompanying enhanced electric field is formed in the gap region. That is, when the luminescent particles 14 are present in the narrow gap region between the metal nanoparticles, the enhanced electric field generated in the gap region acts on the luminescent particles (dipole resonance), so that high intensity light is emitted from the luminescent material. Emitted from particles. Thus, in the conventional structure, the region where the enhanced electric field is formed is a very limited narrow region (a region surrounded by a broken line denoted by reference symbol R1).

  On the other hand, as shown in FIG. 3B, in the present embodiment, the thickness S2 (S2 is, for example, 5 nm) in which the surface of the metal nanoparticles 32 having the diameter D2 (D2 is, for example, 60 nm) includes the phosphor particles 14 is included. A part of the wavelength conversion particle 10 is embedded in the metal film 9 in a state of being covered with the dielectric layer 33. With this structure, the metal nanoparticles 32 and the metal film 9 are opposed to each other with the dielectric layer 33 therebetween, so that a gap region is formed, and many phosphor particles 14 are formed in the gap region between the metal nanoparticles 32 and the metal film 9. Exists. As described above, in the structure of the present embodiment, the region where the enhanced electric field is formed is a region wider than the conventional region (the region surrounded by the two-dot chain line denoted by reference symbol R2), and the luminous body existing in the region where the enhanced electric field is formed. The number of particles 14 can be increased more than before. Thereby, the intensity | strength of light emission can be raised rather than before. Furthermore, when the depth at which the wavelength converting particles 10 are embedded in the metal film 9 is increased within a predetermined range, the region where the enhanced electric field is formed is further expanded, and the electric field intensity per unit volume can be increased. As a result, since the enhanced electric field generated in the gap region can act on more luminescent particles than in the past, higher intensity light is emitted from the luminescent particles.

The inventors of the present invention performed a simulation of light emission intensity with the conventional structure and the structure of this example. The result will be described.
4A and 4B show simulation models of light emission intensity in the prior art. 4A is a plan view of the wavelength conversion unit, and FIG. 4B is a cross-sectional view taken along the line AA ′ in FIG. 4A.
FIGS. 5A and 5B show simulation models of light emission intensity in this example. FIG. 5A is a plan view of the wavelength conversion unit, and FIG. 5B is a cross-sectional view taken along the line BB ′ of FIG.

Assume a green sub-pixel 15G having a vertical dimension L of 51 μm and a horizontal dimension W of 13 μm. The diameter D1 of the conventional metal (silver) nanoparticles 32 is set to 60 nm, and the gap S1 between the conventional metal nanoparticles 32 is set to 5 nm. The diameter D2 of the metal nanoparticles 32 of this example was 60 nm, and the thickness S2 of the dielectric layer 33 of the wavelength conversion particles 10 (the gap between the metal nanoparticles 32 and the metal film 9) was 5 nm. As the light emitter layer (not shown in FIGS. 4A, 4B, 5A, and 5B), a coumarin 6 dispersed as a light emitter in a transparent resin made of PMMA was used. The number of phosphor (coumarin 6) particles present in the phosphor layer was 2.8 × 10 ⁹ .

  As a conventional structure, as shown in FIGS. 4A and 4B, a structure in which metal nanoparticle pairs 32P are arranged on a glass substrate 35 is assumed. Note that the phosphor particles 14 existing between two adjacent metal nanoparticle pairs 32P were also taken into consideration. On the other hand, as shown in FIGS. 5A and 5B, the metal film 9 made of silver is formed on the glass substrate 35 and the metal film 9 is partially embedded in the structure of this embodiment. Thus, what arranged the wavelength conversion particle | grains 10 was assumed. Conventionally, in this example, the plurality of metal nanoparticles 32 and the wavelength conversion particles 10 are arranged in one layer without overlapping.

Here, as a parameter used for calculating the emission intensity, the occupation area ratio Φ of the particles (metal nanoparticles 32 or wavelength conversion particles 10) per unit area is defined by the following equation (1) or (2).
For the conventional structure,
Φ = (projected area of metal nanoparticle pair 32P) × (number of units) / (pixel area) (1)
In this example,
Φ = (projected area of wavelength converting particle 10) × (number of units) / (pixel area) (2)
(1) The number of units in the formula is the number of a pair of metal nanoparticles 32P. (2) The number of units in the formula is the number of wavelength conversion particles 10.

The inventors of the present invention have shown the relationship between the metal film thickness and the emission peak intensity when the area occupancy Φ of the particles is changed to three types of 0.3, 0.4, 0.9 and the conventional structure and this example. Compared.
The comparison results are shown in FIGS. In addition, since there is no metal film in the conventional structure, the emission peak intensity is shown as a constant value.
FIG. 6 is a graph showing the relationship between the metal film thickness and the emission peak intensity when the particle area occupation ratio Φ is 0.3. FIG. 7 is a graph showing the relationship between the metal film thickness and the emission peak intensity when the particle area occupation ratio Φ is 0.4. FIG. 8 is a graph showing the relationship between the metal film thickness and the emission peak intensity when the particle area occupation ratio Φ is 0.9.
In any graph, the horizontal axis represents the metal film thickness [nm], and the vertical axis represents the emission peak intensity [a. u. ].

For the calculation of the emission peak intensity in this example, (1) a model in which excitation light passes through the metal film 9 and is irradiated onto the luminescent particles in the luminescent layer, and light is emitted from the luminescent particles; (2) When the wavelength conversion particle 10 is irradiated with the excitation light, an enhanced electric field is formed in the gap region between the metal nanoparticle 32 and the metal film 9, and the enhanced electric field acts on the luminescent particles. Two models were assumed:
6 to 8, the emission peak intensity derived from the model (1) is indicated by a curve of A, the emission peak intensity derived from the model (2) is indicated by a curve of B, and the total of both emission peak intensities is shown. The (total emission peak intensity) is indicated by the curve indicated by symbol C. The emission peak intensity in the conventional structure is indicated by a broken line F.

  As shown by the curve of symbol A, for light emission derived from the model (1), as the metal film thickness increases, the excitation light is less likely to pass through the metal film, and the light emitter in the light emitter layer is irradiated. As the amount of light decreases, the emission peak intensity decreases. As indicated by the curve indicated by the symbol B, with respect to the light emission derived from the model (2), as the metal film thickness increases from 0, the formation region of the enhanced electric field due to the plasmon resonance shown in FIG. The peak intensity increases. However, if the metal film thickness becomes too thick, the excitation light becomes difficult to transmit through the metal film, and the emission peak intensity decreases.

  As shown in FIG. 6, when the area occupancy Φ of the particles is 0.3, the amount of the wavelength conversion particles 10 is still small in the present embodiment. Of the total emission peak intensity shown, the emission derived from the model (1) is dominant. Although the total emission peak intensity shows a maximum value when the metal film thickness t is 15 nm, the emission peak intensity in the conventional structure indicated by the straight line F is not exceeded even when the total emission peak intensity becomes maximum.

  On the other hand, as shown in FIG. 7, when the area occupancy Φ of the particles is increased to 0.4, the amount of the wavelength conversion particles 10 is increased to some extent, and the effect of the enhanced electric field is exhibited. Among the total emission peak intensities indicated by, the emission derived from the model (2) is dominant. When the metal film thickness t was 45 nm, the total light emission peak intensity showed the maximum value, and within the range of the metal film thickness t of 5 nm to 60 nm, the light emission peak intensity about 1 to 1.3 times that of the conventional film was obtained. As shown in FIG. 8, when the particle area occupation ratio Φ further increases to 0.9, the light emission derived from the model (2) occupies most of the total light emission. When the metal film thickness t is 45 nm, the total light emission peak intensity is maximum, and the light emission peak intensity is about 1 to 4.5 times that of the conventional film thickness t within a range of at least 5 nm to 70 nm.

  From the above results, when the area occupancy Φ satisfies at least 0.4 ≦ Φ ≦ 0.9, the wavelength conversion unit of the present embodiment is different from the conventional wavelength conversion unit in the range where the metal film thickness t is 5 nm to 60 nm. It was found that the emission peak intensity was higher than that. In particular, the emission peak intensity showed the maximum value when the metal film thickness t was 45 nm.

Hereinafter, in this example, the reason why the emission peak intensity becomes maximum when the metal film thickness t is 45 nm is presumed.
FIG. 9 is a graph showing the relationship between the excitation light intensity, the number of luminescent particles, and the metal film thickness. The horizontal axis of the graph is the metal film thickness [nm], and the vertical axis on the left side of the graph is the intensity of the excitation light [a. u. The vertical axis on the right side of the graph is the number of illuminants (coumarin 6) on which the enhanced electric field acts.
FIG. 10 is a graph showing the relationship between the light extraction efficiency from the phosphor particles, the emission peak intensity, and the metal film thickness. The horizontal axis of the graph is the metal film thickness [nm], and the vertical axis on the left side of the graph is the light extraction efficiency [a. u. The vertical axis on the right side of the graph represents the emission peak intensity [a. u. ].
In FIGS. 9 and 10, it is assumed that the wavelength conversion particles are arranged on the metal film in a hexagonal close-packed manner. At this time, the area occupancy Φ of the wavelength conversion particles per unit area of the metal film is 0.9.

The emission peak intensity was calculated using the relationship of the following formula (3).
(Emission intensity) ∝ ((A) Excitation light intensity irradiated to the metal nanoparticle part in the wavelength conversion layer)
× ((B) Number of inter-gap phosphor particles on which the enhanced electric field acts)
× ((C) Luminescence extraction efficiency from illuminant) (3)

Considering (A) in the formula (3), as shown by the solid line in FIG. 9, the enhanced electric field between the metal nanoparticle and the metal film generated by irradiating the metal nanoparticle part with excitation light is applied to the phosphor particles. When acting, as the metal film thickness t increases, the intensity of the excitation light irradiated to the metal nanoparticle part in the wavelength conversion layer is somewhat reduced by absorption by the metal film.
Considering (B), as shown by a broken line in FIG. 9, when an enhanced electric field between the metal nanoparticle and the metal film generated by irradiating the metal nanoparticle part with excitation light is applied to the phosphor particles, the metal film As the thickness t increases, the number of inter-gap phosphor particles that the enhanced electric field acts on increases.
Considering (C), as shown in FIG. 10, even if the metal film thickness t increases from 0 (zero), the light emission efficiency from the phosphor particles is substantially constant, but the metal film thickness t is 35 nm. If it exceeds, the transmittance of the light emitted from the luminescent particles will decrease, and the light extraction efficiency from the luminescent material will decrease.

When the above three factors (A) to (C) are multiplied, as shown in the solid line graph of FIG. 10, the emission peak intensity shows the maximum value when the metal film thickness t is 45 nm.
The reason is that (a) when the metal film thickness t is less than 45 nm, the number of inter-gap phosphor particles on which the enhanced electric field acts decreases, and (b) when the metal film thickness t is thicker than 45 nm, This is because the excitation light intensity between the particles and the metal film is reduced, and the light extraction efficiency from the light emitting layer is reduced.

  As a summary of the above, FIG. 11 is a graph showing the relationship between the area occupancy rate of the phosphor particles per unit area and the emission peak intensity in the conventional structure and the structure of this example. In FIG. 11, the horizontal axis of the graph represents the area occupancy rate of the phosphor particles per unit area, and the vertical axis of the graph represents the emission peak intensity [a. u. ]. Reference symbol F is a graph of the conventional structure, and reference symbol D is a graph of the structure of the present embodiment.

  In the case of the conventional structure, as shown in FIG. 4 (A), the metal nanoparticle pairs 32P sandwiching the luminescent particles 14 are sequentially arranged adjacent to each other. Increases linearly and slowly as the number of metal nanoparticle pairs increases. On the other hand, in the case of the configuration of this example, the presence of the metal film is dominant in the region where the area occupancy Φ of the phosphor particles is small, and the emission peak intensity is smaller than the conventional one. However, in the region where the area occupancy Φ of the luminescent particles is large, the presence of the wavelength conversion particles is dominant, and the emission peak intensity is increased more than before. Specifically, when the area occupancy Φ of the phosphor particles is in the range of 0.34 or more and 0.9 or less (0.34 ≦ Φ ≦ 0.9), the emission peak intensity of the present embodiment is the light emission of the conventional structure. It becomes higher than the peak intensity.

  Next, FIG. 12 is a graph showing the relationship between the area occupancy rate of the phosphor particles per unit area and the emission peak intensity when the metal film thickness is changed in this example. In FIG. 12, the horizontal axis of the graph represents the area occupancy of the phosphor particles per unit area, and the vertical axis of the graph represents the emission peak intensity [a. u. ]. The metal film thickness t was changed in four types of 5 nm, 15 nm, 20 nm, and 45 nm. In FIG. 12, data of a conventional structure is also shown. Symbol A is a graph with a metal film thickness t of 5 nm, Symbol B is a graph with a metal film thickness t of 15 nm, Symbol C is a graph with a metal film thickness t of 20 nm, and Symbol D is a graph with a metal film thickness t. It is a graph of 45 nm, and the symbol F is a graph of a conventional structure.

  As described above, when the metal film thickness t is 45 nm, the area occupancy Φ of the phosphor particles is in the range of 0.34 to 0.9 (0.34 ≦ Φ ≦ 0.9). The emission peak intensity of is higher than the emission peak intensity of the conventional structure. However, as shown in FIG. 12, when the metal film thickness t is reduced to 15 nm or 20 nm, the range of the area occupation ratio Φ in which the emission peak intensity of the present embodiment exceeds the conventional emission peak intensity is 0.31 or more, 0 .9 or less (0.31 ≦ Φ ≦ 0.9). The reason for this is considered to be that when the metal film thickness t is reduced, the excitation light is likely to pass through the metal film, and the ratio of absorption by the light emitter in the light emitter layer is increased.

  As described above, in this embodiment, the effect of increasing the emission peak intensity is considered assuming the green sub-pixel, but the same effect can be obtained for the red sub-pixel. In the case of the red subpixel, the gap between the metal nanoparticle and the metal film may be increased or the refractive index of the surrounding medium may be increased as compared with the case of the green subpixel.

Hereinafter, a first example of the method for manufacturing the wavelength conversion unit 3 of the green sub-pixel used in the present embodiment will be described with reference to FIGS. 13 (A) to (E) and FIGS. 14 (A) to (D). .
13A to 13E are cross-sectional views showing the method of manufacturing the wavelength conversion unit 3 in the order of steps. 14A to 14D are plan views showing the method of manufacturing the wavelength conversion unit 3 in the order of steps.

  First, as shown in FIGS. 13A and 14A, a polydimethylsiloxane (PDMS) film 37 is formed on one surface of the glass substrate 35. On the other hand, a master mold 38 having a plurality of hemispherical structures 38r is produced. For example, a plurality of structures 38r can be formed by self-organizing polystyrene on a substrate. The diameter of the structure 38r is 90 nm, for example, and the height of the structure 38r is 45 nm, for example.

  Next, after the surface of the master mold 38 on which the structure 38r is formed is pressed against the PDMS film 37, the shape of the structure 38r is transferred to the PDMS film 37 by peeling the master mold 38 from the PDMS film 37. Thereby, the PDMS film 37 having a plurality of hemispherical concave portions 37d is formed on the glass substrate 35. The diameter of the concave portion 37d is, for example, 90 nm, and the depth of the concave portion 37d is, for example, 45 nm.

  Next, as shown in FIGS. 13B and 14B, a metal film 39 (silver film) is formed on one surface of the glass substrate 35 by, for example, vapor deposition. The film thickness of the metal film 39 (silver film) is, for example, 10 nm. For example, the metal film 39 is formed along the surface of the PDMS film 37 and the inner wall surface of the recess 37d by forming the film by a vapor deposition method.

Next, as shown in FIG. 13C, the glass substrate 35 on which the metal film 39 is formed on the surface of the PDMS film 37 and the inner wall surface of the recess 37d is replaced with an aminoalkanethiol (H ₂ NC _n H _{2n + 1} -SH). (n = 2)) Impregnation into the solution. At this time, thiol is adsorbed on the surface side of silver. Thereby, the positively charged amino group (NH ₂ ⁺ ) is terminated.

Next, metal nanoparticles 32 (silver nanoparticles) covered with a dielectric layer 33 (silicon oxide) containing phosphor particles 14 (coumarin 6) on a glass substrate 35 on which a metal film 39 is formed, so-called A solution of wavelength conversion particles 10 is dropped and allowed to stand overnight. At this time, NH ₂ ⁺ (metal film surface) and O ⁻ (wavelength conversion particle surface) exert an electrostatic interaction, so that the wavelength conversion particles as shown in FIGS. 13 (D) and 14 (C). 10 and the concave surface of the metal film 39 are adsorbed to each other.

  Thereafter, when the glass substrate 35 is pulled up from the solution, the wavelength conversion particles 10 for one layer are adsorbed, and the wavelength conversion particles 10 that have not been subjected to electrostatic interaction remain in the solution. In this way, the metal film 39 (coumarin 6 / silver nanoparticle structure) in which the wavelength conversion particles 10 for one layer are embedded is formed. Since the interval between the wavelength conversion particles 10 is determined by the height of the structure 38r of the master mold 38 and the interval between the structures 38r, it can be freely adjusted.

  Here, the manufacturing method of a wavelength conversion particle solution is demonstrated using FIG. 15 (A)-(D). As a means for forming silicon oxide, hydrolysis / polycondensation reaction of TEOS (Tetraethyl orthosilicate) was used.

First, as shown in FIG. 15 (A), a silver nanoparticle aqueous solution 41 with citrate (particle diameter of silver nanoparticles 42: 60 nm, concentration of silver nanoparticles 42: 1.7 × 10 ¹⁰ particles / mL: to _{sigma-Aldrich),} turning on the H 2 O / EtOH mixture.

Next, as shown in FIG. 15B, coumarin 6 (0.2 ml, 1.0 × 10 ⁻² M in EtOH) is added as a luminescent material to the solution 43 prepared in the previous step. The rotor 44 is sufficiently stirred. Then, TEOS (0.2 ml, 1.0 × 10 ⁻³ M in EtOH) is added and stirred well. At this time, the temperature of the water bath is kept constant at 35 ° C.
15 minutes after adding TEOS, base catalyst NaOH (0.2 ml, 0.1 M) is added and the solution 43 is allowed to react for about 6 hours with stirring. At this time, the concentration of water with respect to ethanol is set to 55.6 mol / l. The volume of the preparation solution is 2 mL.

  After the reaction, as shown in FIG. 15C, a solution 45 of silicon oxide-coated silver nanoparticles containing so-called coumarin 6, so-called wavelength conversion particles 10, is formed. However, since there exist excess coumarin 6, NaOH, etc. as an impurity, the following processes are performed.

Excess coumarin 6 present in the solution 45 is removed by centrifuging the solution 45 prepared in the previous step. That is, since the precipitate (reactant) and the supernatant are separated by centrifugation, after collecting the supernatant, the precipitate is diluted with water. By repeating this operation several times, excess coumarin 6 can be removed. Silver nanoparticles 32 (final formed product) having a thickness of 5 nm of silicon oxide 33 are produced. When the silver nanoparticles 32 are dispersed in water, a deprotonation reaction of the OH group on the surface of the silicon oxide 33 occurs and is negatively charged with O ^{− as} shown in FIG. Note that the particle size distribution before and after the silicon oxide coating can be measured by DLS (Dynamic Light Scattering) measurement for the particles produced in the previous step. Therefore, the mode value of the particle size of the obtained particles can be grasped.
A wavelength conversion particle solution can be manufactured by the above process.

Next, as shown in FIGS. 13 (E) and 14 (D), PMMA and coumarin 6 (weight ratio of 1.0 wt% with respect to PMMA) are used as the chloroform solvent on the glass substrate 35 on which the wavelength conversion particles 10 are adsorbed. By applying a solution in which is dispersed, a light emitting layer 11G of a green sub-pixel having a thickness of 7 μm is formed. Note that the mixing ratio of coumarin 6 is 1.0 wt% in terms of the weight ratio to PMMA. Increasing the concentration beyond this is not practical because it does not dissolve in the solvent.
Note that the light emitting layer of the red sub-pixel can be produced in the same procedure by changing the dye to be used from coumarin 6 to lumogen red 305.

Next, the glass substrate having a wavelength conversion layer prepared by the above procedure and a transparent base material are bonded together to manufacture the wavelength conversion unit 3. Then, the excitation light source part 2 and the wavelength conversion part 3 which were produced separately are bonded together.
Through the above steps, the light emitting device 1 of this example is completed.

Hereinafter, a second example of the method for manufacturing the wavelength conversion unit of the present embodiment will be described with reference to FIGS.
First, the glass substrate is immersed in a palladium chloride solution. Thereby, a catalyst metal is provided to the surface of the glass substrate.
Next, the glass substrate provided with the catalytic metal is immersed in an electroless copper plating bath (copper nitrate or the like, bath temperature: 50 ° C., pH 11.5). As a result, a copper film 46 having a thickness of 5 nm is formed on the surface of the glass substrate 35 as shown in FIG. The copper film 46 contributes to improving the adhesion between silver to be formed later and the glass substrate 35.
Thereafter, the glass substrate 35 on which the copper film 46 is formed is put into an electric furnace and held at a temperature of 400 ° C. for 30 minutes.

Next, the surface of the copper film 46 on the surface of the glass substrate 35 is modified with aminoalkanethiol (H ₂ NC _n H _{2n + 1} -SH (n = 2)). Thereafter, the glass substrate 35 is immersed in an aqueous solution of coumarin 6-containing silica-coated silver nanoparticles (wavelength conversion particles) overnight. Thereby, as shown in FIG. 16B, the wavelength conversion particles 10 are adsorbed on the surface of the copper film 46.

  Next, the glass substrate 35 on which the wavelength converting particles 10 are adsorbed is immersed in an electroless copper plating bath (silver cyanide, bath temperature 30 ° C.). Thereby, as shown in FIG. 16C, a silver film 47 is formed on the copper film 46, and a part of the wavelength conversion particles 10 is embedded in the silver film 47. The film thickness of the silver film 47 is 45 nm, for example.

  Next, on the wavelength conversion particle 10 and the silver film 47, a phosphor layer made of PMMA containing coumarin 6 as shown in FIG. 16D by the same method as in the first example described above. 11G is formed. Through the above process, the wavelength conversion layer of the green sub-pixel is completed.

Hereinafter, a third example of the method for manufacturing the wavelength conversion unit of the present embodiment will be described with reference to FIGS.
First, a silver film is formed on a glass substrate by vapor deposition or the like. Thereafter, the silver film formed on the glass substrate is annealed (temperature: 200 ° C., time: 40 minutes) in a nitrogen atmosphere. Thereby, as shown in FIG. 17A, a silver island film 48 in which silver is present in isolation is formed on the surface of the glass substrate 35.

Next, the glass substrate 35 on which the silver island film 48 is formed is impregnated overnight in an ethanol solution of 3-aminopropyltriethoxysilane (APTES). As a result, as shown in FIG. 17B, the surface of the glass substrate 35 other than the surface of the silver island film 48 is modified with a positively charged amino group (NH ₂ ⁺ ).

  Next, the glass substrate 35 whose surface is modified with an amino group is taken out from the ethanol solution. Thereafter, the glass substrate 35 is immersed in an aqueous solution of coumarin 6-containing silica-coated silver nanoparticles (wavelength conversion particles) overnight. Thereby, as shown in FIG. 17C, the surface of the silver island film 48 and the wavelength conversion particles 10 are electrostatically adsorbed. Thereafter, the glass substrate 35 is dried in an oven.

  A phosphor made of PMMA containing coumarin 6 as shown in FIG. 17D on the glass substrate 35 on which the wavelength converting particles 10 are electrostatically adsorbed by the same method as in the first example described above. Layer 11G is formed. Through the above process, the wavelength conversion layer of the green sub-pixel is completed.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the light emitting device of the second embodiment is the same as that of the light emitting device of the first embodiment, and the configuration of the metal film that embeds part of the wavelength conversion particles is different from that of the first embodiment.
FIG. 18 is a cross-sectional view of the light emitting device of the second embodiment.
18, the same code | symbol is attached | subjected to the same component as drawing used in 1st Embodiment, and detailed description is abbreviate | omitted.

  As shown in FIG. 18, in the light emitting device 51 of the second embodiment, the metal film 52 constituting a part of the wavelength conversion layer 53 has a first region 52a in which the transmittance of excitation light is smaller than that of the second region. And a second region 52b having a higher transmittance of excitation light than the first region. In the case of the second embodiment, the first region 52a is a region where a metal film such as silver is present. The second region 52b is a region where there is no metal film and the opening of the metal film is filled with a substance having a higher excitation light transmittance than the metal film. Examples of a substance having a higher transmittance of excitation light than a metal film such as silver include air, an arbitrary light transmissive material, and an upper light emitting layer material.

  When the metal film 52 is viewed from the normal direction, a region where the wavelength conversion particles 10R and 10G are present, that is, a circular region obtained by projecting the outer shape of the wavelength conversion particles 10R and 10G onto the metal film 52 is the first region. 52a substantially matches. A region where the wavelength conversion particles 10R and 10G are not present, that is, a region other than the circular region substantially coincides with the second region 52b. However, the circular area may not necessarily completely match the first area 52a, and the area other than the circular area may not completely match the second area 52b. It suffices that at least a part of the circular region overlaps the first region 52a and at least a part of the region other than the circular region overlaps the second region 52b. Other configurations are the same as those of the first embodiment.

  Also in the configuration of the second embodiment, as in the first embodiment, more phosphor particles 14R and 14G emit light with higher intensity than before due to the electric field enhancement effect in the gap region between the metal nanoparticles 32 and the metal film 52. To do. Further, in the present embodiment, the region where the wavelength conversion particles 10R and 10G are not present is the second region 52b where the metal film 52 is not present and the transmittance of the excitation light is large. Therefore, the attenuation amount of the excitation light incident on the second region 52b (absorption amount by the metal film 52) is smaller than that in the first embodiment, and the excitation light is in the second region 52b in which the wavelength conversion particles 10R and 10G are not present. The phosphor particles 14R and 14G in the phosphor layers 11R and 11G are irradiated with the intensity maintained. Therefore, the intensity of light emitted from the light emitter particles 14R and 14G in the light emitter layers 11R and 11G is higher than that in the first embodiment.

  FIG. 19 is a graph comparing the relationship between the area occupancy of the wavelength conversion particles 10R and 10G and the emission peak intensity in the conventional example, the first embodiment, and the second embodiment. The horizontal axis of the graph represents the area occupancy Φ of the wavelength conversion particles per unit area of the metal film. The vertical axis of the graph represents the emission peak intensity [a. u. ]. The graph indicated by the symbol A is data of the light emitting device of the first embodiment. A graph indicated by a symbol B is data of the light emitting device of the second embodiment. A graph indicated by a symbol F is data of a conventional light emitting device. The film thickness of silver (metal film) was 45 nm.

  As shown in FIG. 19, when comparing the graph A of the first embodiment and the graph B of the second embodiment, particularly in a region where the area occupancy Φ of the wavelength conversion particles is small, the second region where no wavelength conversion particles are present. The effect of the second embodiment that the amount of attenuation of the excitation light incident on the light source decreases becomes significant. As a result, the emission peak intensity of the second embodiment is greater than the emission peak intensity of the first embodiment. In the case of the first embodiment, the area occupancy Φ of the phosphor particles is higher than the emission peak intensity of the conventional structure in the range of 0.34 to 0.9 (0.34 ≦ Φ ≦ 0.9). On the other hand, in the case of the second embodiment, the area occupancy Φ of the phosphor particles is in the range of 0.20 or more and 0.9 or less (0.20 ≦ Φ ≦ 0.9) than the emission peak intensity of the conventional structure. Get higher. As described above, according to the light emitting device of the second embodiment, the range of the area occupancy Φ of the luminescent particles that can increase the emission peak intensity more than before can be expanded.

  FIG. 20 shows the relationship between the area occupancy Φ of the wavelength conversion particles and the emission peak intensity when the film thickness of silver (metal film) is changed in the light emitting device of the second embodiment added to the data of FIG. It is. The horizontal axis of the graph represents the area occupancy Φ of the wavelength conversion particles per unit area of the metal film. The vertical axis of the graph represents the emission peak intensity [a. u. ]. The graph indicated by the symbol A is data of the light emitting device of the first embodiment. The graph indicated by symbol B is data when the film thickness of silver (metal film) is 5 nm in the second embodiment. The graph indicated by symbol C is data when the film thickness of silver (metal film) is 15 nm in the second embodiment. The graph indicated by the symbol D is data when the film thickness of silver (metal film) is 20 nm in the second embodiment. The graph indicated by symbol E is data when the film thickness of silver (metal film) is 45 nm in the second embodiment. A graph indicated by a symbol F is data of a conventional light emitting device.

  As shown in the graph of symbol E, in the second embodiment, when the film thickness of silver (metal film) is 45 nm, the area occupation ratio Φ of the phosphor particles is in the range of 0.20 or more and 0.9 or less (0 .20 ≦ Φ ≦ 0.9), which is higher than the emission peak intensity of the conventional structure. From the data in FIG. 20, it was found that when the film thickness of silver (metal film) is 45 nm, the range of the area occupancy Φ of the phosphor particles where the emission peak intensity is higher than the conventional one is the widest.

Hereinafter, an example of the manufacturing method of the wavelength conversion part of 2nd Embodiment is demonstrated using FIG. 21 (A)-(D) and FIG. 22 (A)-(D).
First, a glass substrate is covered with a pattern mask, and the glass substrate is immersed in a palladium chloride solution. Thereby, a catalyst metal is provided to the region corresponding to the opening of the pattern mask on the surface of the glass substrate.

Next, the glass substrate provided with a catalytic metal on a part of the surface is immersed in an electroless copper plating bath (such as copper nitrate: bath temperature 50 ° C., pH 11.5). Thereby, a copper film having a thickness of 5 nm is formed on the surface of the glass substrate. The reason for forming the copper film is to improve the adhesion between the silver-glass substrate.
Thereafter, the glass substrate on which the copper film is formed is put into an electric furnace and held at a temperature of 400 ° C. for 30 minutes. Then, as shown in FIG. 21A, the pattern mask 54 is peeled from the glass substrate 35. Thereby, a patterned copper film 55 is formed on the surface of the glass substrate 35.

Next, the surface of the copper film 55 on the glass substrate 35 is modified with aminoalkanethiol (H ₂ NC _n H _{2n + 1} -SH (n = 2)). Thereafter, for the wavelength conversion part of the green sub-pixel 15G, the glass substrate is similarly applied to the aqueous solution of silica-coated silver nanoparticles (wavelength conversion particles) containing coumarin 6 and the wavelength conversion part of the red sub-pixel 15R. Are each immersed in an aqueous solution of coumarin 6-containing silica-coated silver nanoparticles (wavelength conversion particles) overnight. Thereby, the wavelength conversion particles 10 are adsorbed on the surface of the copper film 55 as shown in FIGS.

  Next, the glass substrate 35 on which the wavelength converting particles 10 are adsorbed is immersed in an electroless silver plating bath (silver cyanide, etc .: bath temperature 30 ° C.). Thus, as shown in FIGS. 21C and 22C, the silver film 47 is formed in a state where the lower side of the wavelength conversion particle 10 is buried in the silver film 47. However, in the second embodiment, the silver film 47 is selectively formed on the patterned copper film 55. The film thickness of the silver film 47 is, for example, 45 nm.

  Next, on the glass substrate 35 on which the silver film 47 is formed, as shown in FIGS. 21D and 22D, the wavelength conversion unit of the green sub-pixel 15G is formed by the same method as in the first embodiment. On the other hand, the light emitter layer 11G made of PMMA containing coumarin 6 is formed, and the light emitter layer 11R made of PMMA containing rhodamine 101 is formed for the wavelength conversion part of the red sub-pixel 15R. Thereby, the wavelength conversion layers of the green sub-pixel 15G and the red sub-pixel 15R are completed. When this manufacturing method is used, the light emitting layer material having a higher transmittance of excitation light than the silver film is present in the second region 52b.

  FIG. 23 shows absorption / emission spectra of coumarin 6 and rhodamine 101. From this, it can be seen that coumarin 6 has an absorption maximum wavelength of 450 nm / emission maximum wavelength: 500 nm, and rhodamine 101 has an absorption maximum wavelength of 570 nm / emission maximum wavelength: 590 nm.

Using this result, the color conversion principle of the wavelength conversion layer of the red sub-pixel 15R will be described.
First, an irradiating electric field is formed in the vicinity of the metal nanoparticles 32 (resonance wavelength: 450 nm) by irradiating the wavelength conversion layer with excitation light in the blue region (emission maximum wavelength: 450 nm). Thereafter, the enhanced electric field of the metal nanoparticles 32 acts on coumarin 6 (absorption maximum wavelength 450 nm / emission maximum wavelength: 500 nm) having a higher absorbance in the blue region than rhodamine 101 (absorption maximum wavelength 570 nm / emission maximum wavelength: 590 nm). To do. This means that coumarin 6 can exchange excitation light energy more efficiently than rhodamine 101. At this time, energy is transferred to rhodamine 101 in the luminescent layer dispersed in the vicinity of coumarin 6 by Forster energy transfer between coumarin 6 and rhodamine 101. As a result, high intensity light (emission maximum wavelength: 590 nm) is emitted through rhodamine 101. Incidentally, the energy transfer efficiency is sufficiently high since the overlap between the emission spectrum of coumarin 6 and the absorption spectrum of rhodamine 101 is large.
As described above, the phosphor particles contained in the dielectric layer 33 of the wavelength conversion particle 10R and the phosphor particles contained in the phosphor layer 11R are selected differently, thereby increasing the conversion efficiency from blue to red. be able to.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the light emitting device of the third embodiment is the same as that of the light emitting device of the first embodiment, but the first embodiment is that excitation light is incident from one surface of the wavelength conversion unit and light is emitted from the same surface. Different from form.
FIG. 24 is a cross-sectional view of the light emitting device of the third embodiment.
In FIG. 24, the same components as those used in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As illustrated in FIG. 24, the light emitting device 61 according to the third embodiment includes an excitation light source unit 62, a wavelength conversion unit 63, and a dichroic mirror 64. In 1st Embodiment, the excitation light source part was provided facing the 1st surface (lower surface in FIG. 1) of the wavelength conversion part. On the other hand, in 3rd Embodiment, the excitation light source part 62 is provided facing the 2nd surface 63b (upper surface in FIG. 24) of the wavelength conversion part 63. FIG.

  In the excitation light source unit 62, the constituent material of the cathode (not shown) is different from that of the first embodiment. In the first embodiment, a metal such as Li, Ca, Ce, Ba, or Al, or an alloy such as an Mg: Ag alloy or Li: Al alloy containing these metals is used as the constituent material of the cathode. . On the other hand, in the third embodiment, a transparent conductive material such as ITO or IZO is used as a constituent material of the cathode. In the third embodiment, IZO with high light transmittance for blue light is used. IZO is formed by sputtering, for example. The light transmittance of IZO is about 80% with respect to blue light having a wavelength of 450 nm. Thereby, in 3rd Embodiment, the whole excitation light source part 62 has a light transmittance over substantially the whole visible region. Components other than the cathode are the same as those in the first embodiment.

  In the wavelength conversion unit 63, the film thickness t3 of the metal film 65 constituting a part of the wavelength conversion layer 66 is larger than the film thickness of the metal film of the first embodiment. In the first embodiment, the thickness of the metal film is about 45 nm. On the other hand, in the third embodiment, the film thickness t3 of the metal film 65 is, for example, about 200 nm. Thereby, the metal film 65 has a film thickness that can sufficiently reflect visible light, and the reflectance with respect to light having a wavelength of 400 to 800 nm is 95% or more. In the red subpixel 15R and the green subpixel 15G, the metal film 65 is provided on the second surface 8b of the third substrate 8. In the blue subpixel 15 </ b> B, the metal film 65 is provided on the first surface 12 a of the fourth substrate 12. Components other than the metal film 65 are the same as those in the first embodiment.

  In the phosphor layers 11R and 11G of the wavelength conversion layer 66, in addition to the phosphor particles 14R and 14G, metal nanoparticles 40 are dispersed. In this embodiment, the material of the metal nanoparticles 40 is a silica sphere coated with silver. The sizes were (inner diameter, outer diameter) = (30, 50), (10, 50) (unit: [nm]), respectively. At this time, the scattering intensity spectrum by plasmons is as shown in FIGS. 25 (A) and 25 (B). Thus, the resonance wavelengths of plasmons are 600 and 500 nm, respectively, and the half-value widths of those spectra are 10 and 20 nm, respectively. On the other hand, the luminous maximum wavelengths of the phosphor particles 14R and 14G, that is, lumogen red and coumarin 6, are 600 and 500 nm, respectively, and their spectral half widths are 50 and 60 nm, respectively.

  Note that the ratio {(scattering) / (absorption + scattering)} of scattering and absorption due to plasmon resonance tends to increase greatly in the case of a metal-coated dielectric sphere compared to a metal sphere of the same particle size. As an example, FIG. 26 shows an absorption / scattering spectrum of a silica sphere coated with silver (inner diameter, outer diameter) = (10, 50). From this, it is understood that the {(scattering) / (absorption + scattering)} ratio is about 0.91 at the resonance wavelength. This means that rumogen red present in the vicinity of silver transfers energy to the silica particles coated with silver present in the vicinity when the excitation light is absorbed, and about 91% of the absorbed energy from the silica particles coated with silver. % Is emitted as resonance scattering.

  The particle diameter D3 of the wavelength conversion particles 10R and 10G is, for example, 60 nm as in the first embodiment, and is smaller than the film thickness t3 of the metal film 65. However, it is preferable that the wavelength conversion particles 10 </ b> R and 10 </ b> G are not completely buried in the metal film 65. Specifically, it is preferable that r ≦ 1/2 × D3 is satisfied, where r is the distance from the first surfaces 11Ra, 11Ga of the light emitting layers 11R, 11G to the centers of the wavelength conversion particles 10R, 10G. When the above conditions are satisfied, the wavelength conversion particles 10R and 10G are buried in the metal film 65 from the position where the wavelength conversion particles 10R and 10G are in contact with the metal film 65, and the wavelength conversion particles 10R and 10G have a metal on the upper part. There will be somewhere between the position where the film 65 does not exist.

  The reason why the above conditions are preferable is that the wavelength conversion particles 10 </ b> R and 10 </ b> G cannot obtain the electric field enhancement effect in the gap region between the metal nanoparticle 32 and the metal film 65 unless they are in contact with the metal film 65. Further, when the wavelength conversion particles 10R and 10G are buried too deeply in the metal film 65 and the metal film 65 exists above the wavelength conversion particles 10R and 10G, the excitation light is absorbed by the metal film 65 and the wavelength conversion particles 10R, 10G, This is because it becomes difficult to reach 10G and the electric field enhancement effect is weakened.

  A dichroic mirror 64 is used in the wavelength selection unit of this embodiment. The dichroic mirror 64 is provided on the surface opposite to the side where the wavelength conversion unit 63 of the excitation light source unit 62 is provided (the upper surface of the excitation light source unit 62 in FIG. 24). The dichroic mirror 64 is provided in the red subpixel 15R and the green subpixel 15G, and is not provided in the blue subpixel 15B. The dichroic mirror 64 has a characteristic of reflecting light in the blue region and transmitting light outside the blue region. The dichroic mirror 64 has, for example, a reflectance of 95% for light having a wavelength of 450 nm and a transmittance of 70% for light having a wavelength of 500 nm.

  With the above configuration, the light-emitting device 61 of the third embodiment is a reflective light-emitting device that allows excitation light to enter from one surface of the wavelength conversion unit 63 and emit light from the same surface. That is, as shown in FIG. 24, in the red subpixel 15R and the green subpixel 15G, the excitation light L1 traveling from the excitation light source unit 62 toward the wavelength conversion unit 63 is transmitted through the fourth substrate 12 of the wavelength conversion unit 63. Then, the light enters the light emitter layers 11R and 11G. In addition, the excitation light L2 traveling from the excitation light source unit 62 toward the opposite side of the wavelength conversion unit 63 is reflected by the dichroic mirror 64, and then passes through the fourth substrate 12 of the wavelength conversion unit 63 to transmit the light emitter layers 11R, 11R, Incident on 11G.

  A part of the excitation light (light emission maximum wavelength: 450 nm) incident on the light emitter layers 11R and 11G is absorbed by the light emitter particles 14R and 14G, and light is generated from the light emitter particles 14R and 14G. At this time, most of the phosphor particles 11R and 11G that have absorbed the excitation light transfer energy to the metal nanoparticles 40 existing in the vicinity of the phosphor particles 11R and 11G. To emit light (by resonance scattering) from the metal nanoparticles 40. That is, the emission spectra of red and green light are a combination of a part of the light emitted from the phosphor particles 14R and 14G and the most of the light emitted through the metal nanoparticles, but the influence of the former is smaller than that of the latter. A narrow wavelength region specific to resonance is generated.

  Of the excitation light incident on the illuminant layers 11R and 11G, the other excitation light L3 is absorbed by the illuminant particles 14R and 14G in the gap region between the metal nanoparticle 32 and the metal film 65 in the wavelength conversion particles 10R and 10G. Then, light is generated from the phosphor particles 14R and 14G. Although the phosphor particles 14R and 14G emit isotropically, in the third embodiment, since the metal film 65 is sufficiently thick, the light traveling downward from the isotropically emitted light is reflected by the metal film 65, Proceed upward. The light L4 emitted from the wavelength conversion unit 63 sequentially passes through the excitation light source unit 62 and the dichroic mirror 64 and is emitted to the viewing side (upper side in FIG. 24).

  In the blue sub-pixel 15B, the excitation light L5 traveling from the excitation light source unit 62 toward the wavelength conversion unit 63 is reflected by the metal film 65 of the wavelength conversion unit 63 and passes through the excitation light source unit 62, and is viewed on the viewer side (FIG. 24). Above). Further, the excitation light traveling from the excitation light source unit 62 toward the side opposite to the wavelength conversion unit 63 is emitted as it is to the viewing side (upward in FIG. 24).

  Also in the light emitting device 61 of the third embodiment, as in the first embodiment, due to the electric field enhancement effect in the gap region between the metal nanoparticle 32 and the metal film 65, more light emitter particles 14R and 14G have higher intensity than before. Flashes on. Further, in the case of the present embodiment, the excitation light is incident from the second surfaces 11Rb and 11Gb of the light emitter layers 11R and 11G and cannot be absorbed when the light emitter layers 11R and 11G travel once in the film thickness direction. The light is reflected by the metal film 65 and travels again in the light emitting layers 11R and 11G. That is, the optical path length of the excitation light passing through the light emitter layers 11R and 11G is longer than that of the conventional and first embodiments. Therefore, the amount of excitation light absorbed by the luminescent particles 14R and 14G in the third embodiment is increased about twice. As a result, according to the light emitting device 61 of the third embodiment, higher intensity light can be obtained as compared with the light emitting devices of the first embodiment and the second embodiment.

  Furthermore, the metal nanoparticles 40 existing in the vicinity of the phosphor particles 14R and 14G may transfer energy from the phosphor particles 14R and 14G that have absorbed the excitation light to the metal nanoparticles 40 and emit light through the metal nanoparticles 40. it can. Therefore, in this embodiment, an effect of improving color purity is also obtained.

[Fourth Embodiment: Lighting Device]
Hereinafter, the illuminating device of 4th Embodiment of this invention is demonstrated using FIGS. 27-29.
FIG. 27 is a perspective view showing the illumination device of the fourth embodiment. FIG. 28 is a cross-sectional view taken along the line CC ′ of FIG. FIGS. 29A to 29C are diagrams for explaining how to use the lighting device.
27 to 29, the same reference numerals are given to the same components as those used in the previous embodiment, and the description thereof is omitted.

  As shown in FIG. 27, the illumination device 71 of the fourth embodiment has a shape obtained by cutting a cylinder along a plane parallel to the central axis of the cylinder. The surface 71a from which the illumination light is emitted is a curved surface curved inward, and the illumination light LO is emitted toward the side where the cylinder is opened. When the illumination device 71 has a size equivalent to, for example, a 40-inch size fluorescent tube, the length A of the illumination device 71 may be about 120 cm and the width B (outer diameter) may be about 3 cm, for example.

  As illustrated in FIG. 28, the illumination device 71 includes an excitation light source unit 72 and a wavelength conversion unit 73. The lighting device 71 includes a first transparent base material 74, a second transparent base material 75, and a third transparent base material 76. The first transparent substrate 74, the second transparent substrate 75, and the third transparent substrate 76 are all made of a flexible plastic film. Thereby, the user can bend this illuminating device 71 freely at the time of use. Of the three transparent substrates, the second transparent substrate 75 located at the center serves as both the substrate of the excitation light source unit 72 and the substrate of the wavelength conversion unit 73.

  The excitation light source unit 72 emits blue excitation light L1. As the excitation light source unit 72, for example, the same excitation light source unit 2 as in the first embodiment can be used, and thus detailed description thereof is omitted. The phosphor layer 11Y constituting the part of the wavelength conversion layer 77 and the phosphor particles 14Y in the wavelength conversion particle 10Y absorb part of the blue excitation light and emit white light from the wavelength conversion unit 73. A combination is chosen. In the fourth embodiment, coumarin 6 (absorption maximum wavelength 450 nm / light emission maximum wavelength: 500 nm) and rhodamine 101 (absorption maximum wavelength 570 nm / light emission maximum) are respectively used as the light emitter particles 14Y in the light emitter layer 11Y and the wavelength conversion particles 10Y. Wavelength: 590 nm) is used.

  A part of the excitation light L1 emitted from the excitation light source part 72 is absorbed by the illuminant layer 11Y and the illuminant particle 14Y in the wavelength conversion part 73, and wavelength-converted into green and red light (= yellow light LY), Green and red light (= yellow light LY) (wavelength: 500 nm to 590 nm) is emitted from the wavelength conversion unit 73. The other part of the excitation light L1 emitted from the excitation light source 72 is not absorbed by the light emitter layer 11Y and the light emitter particles 14Y, and blue light LB (light emission maximum wavelength: 450 nm) is emitted from the wavelength converter 73. The As a result, white light in which green and red light (= yellow light LY) and blue light LB are combined is emitted from the illumination device 71 of the present embodiment. At this time, since the light emitted from the wavelength region 450 to 590 nm, that is, the wavelength conversion unit 73 is wide from blue to red, white light having a wide wavelength region can be generated.

  In the illumination device 71 of the fourth embodiment, many phosphor particles 14Y emit light with high intensity due to the electric field enhancement effect in the gap region between the metal nanoparticles 32 and the metal film 9. Further, in the present embodiment, since the illumination device 71 is curved, a part of the light L1 ′ of the excitation light L1 is emitted from a specific portion of the wavelength conversion unit 73 without being absorbed by the luminescent particles 14Y. Even so, the light is incident again on the wavelength conversion unit 73 in the region facing the specific portion. Thereby, the optical path length of the excitation light L1 passing through the light emitter layer 11Y becomes longer. Therefore, in the illuminating device 71 of the fourth embodiment, the amount of absorption of the excitation light L1 by the luminescent particles 14Y is greatly increased compared to the case where the illuminating device is not curved. As a result, according to the illumination device 71 of the fourth embodiment, high-intensity white light is obtained.

As shown in FIGS. 29A to 29C, the way of lighting can be changed by changing the way the lighting device 71 is bent.
As shown in FIG. 29A, by bending the lighting device 71 inward, it can be used for an application where it is desired to intensively brighten the area directly under the lighting device 71, such as spot lighting. As shown in FIG. 29B, by flattening the lighting device 71, it can be used as a lighting device for uniformly lighting the entire room. As shown in FIG. 29C, the lighting device 71 can be bent outward so that the room can be brightened in a wider range.

[Fifth Embodiment: Lighting Device]
Hereinafter, the illuminating device of 5th Embodiment of this invention is demonstrated using FIG.
The basic configuration of the illumination device of the fifth embodiment is the same as that of the illumination device of the fourth embodiment, and the configuration of the excitation light source unit is different.
FIG. 30 is a cross-sectional view of the illumination device of the fifth embodiment.
In FIG. 30, the same code | symbol is attached | subjected to the same component as drawing used in 4th Embodiment, and description is abbreviate | omitted.

  In the illumination device of the fourth embodiment, an organic EL element is used as the excitation light source unit. On the other hand, the illuminating device 81 of 5th Embodiment uses the light-guide plate 83 and the light emitting diode 84 (LED) as the excitation light source part 82. FIG. The light guide plate 83 is made of, for example, flexible acrylic resin. A plurality of LEDs 84 that emit blue light are provided on the end surface 83 a of the light guide plate 83. A diffusion film 85 that diffuses incident light is provided between the light guide plate 83 and the second transparent substrate 75. In this example, the plurality of LEDs 84 are provided on the end surface 83 a of the light guide plate 83, but may be provided on the curved surface 83 b of the light guide plate 83. The configuration of the wavelength conversion unit 73 is the same as that of the fourth embodiment.

  In the case of the illumination device 81 according to the fifth embodiment, the blue light LB (excitation light) emitted from the LED 84 is guided by the diffusion film 85 while being guided through the light guide plate 83, and the second light. The light passes through the transparent substrate 75 and isotropically emitted toward the wavelength conversion unit 73. After that, as in the illumination device of the fourth embodiment, a part of the excitation light L1 emitted from the excitation light source unit 82 is absorbed by the phosphor particles 14Y in the wavelength conversion unit 73 and wavelength-converted to yellow light LY. The light LY is emitted from the wavelength conversion unit 73. The other part of the excitation light L1 emitted from the excitation light source unit 82 is not absorbed by the luminescent particles 14Y, and the blue light LB is emitted from the wavelength conversion unit 73 as it is. As a result, the illumination device 81 emits white light obtained by combining the yellow light LY and the blue light LB.

  Also in the fifth embodiment, an effect similar to that of the fourth embodiment can be obtained, that is, an illuminating device that can obtain high-intensity white light can be realized. Furthermore, in the case of this embodiment, high intensity | strength illumination light can be obtained only by adhere | attaching the wavelength conversion part 73 with respect to a commercially available LED illuminating device.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the above embodiment is an example of wavelength conversion particles in which the periphery of one metal nanoparticle is coated with a dielectric layer containing phosphor particles, and the dielectric layer is provided around the spherical metal nanoparticle. Therefore, the film thickness of the dielectric layer, that is, the gap between the metal nanoparticle and the metal film is constant. For example, the gap between the metal nanoparticle and the metal film was unified at about 5 nm.
On the other hand, wavelength conversion particles 90 in which a plurality of metal nanoparticles 32 and a plurality of phosphor particles 14 are dispersed in a dielectric layer 33 may be used, as in the wavelength conversion particles 90 shown in FIG. In this case, the gaps between the metal nanoparticles 32 and the metal film 9 and between the metal nanoparticles 32 and the metal nanoparticles 32 are not constant and are different as G1, G2, and the like. As a result, enhanced electric fields having different plasmon resonance wavelengths act on the phosphor particles 14 existing in G1 and G2, respectively. Therefore, in the case of this structure, the metal-metal gap has a range of, for example, 1 nm to 5 nm, so that excitation light in a wide wavelength range can be efficiently absorbed.

  Therefore, by using the wavelength conversion particle 90 of FIG. 31, for example, not only blue light with a wavelength of 450 nm but also excitation light in a wide wavelength range from blue light with a wavelength of 450 nm to green light with a wavelength of 550 nm is emitted from the phosphor particles 14. It is possible to efficiently convert the wavelength into light of a wavelength. By using the wavelength conversion particles 90 for, for example, a light guide plate of a solar cell module, light having a wide range of wavelengths can be used for solar power generation without wasting sunlight.

  As described above, the wavelength conversion particles used in the present invention can be used not only for display devices and illumination devices but also for solar cell modules. When the wavelength conversion particle of the present invention is used in a solar cell module, when sunlight is directly irradiated to and absorbed by the luminescent particles, light generated from the luminescent particles, when sunlight is irradiated and absorbed by the wavelength converted particles Both light generated from the wavelength conversion particles can be used for photovoltaic power generation.

  The present invention can be used for various display devices such as an organic EL display or a lighting device.

  DESCRIPTION OF SYMBOLS 1,51,61 ... Light-emitting device (display device), 2,72 ... Excitation light source part, 3,73 ... Wavelength conversion part, 4, 53, 66, 77 ... Wavelength conversion layer, 9, 52, 65 ... Metal film, 10, 10R, 10G, 10Y, 90 ... wavelength conversion particles, 11, 11R, 11G, 11Y ... phosphor layer, 14, 14R, 14G, 14Y ... phosphor particles, 32, 40 ... metal nanoparticles, 33 ... dielectric Layer 52a ... 1st area | region 52b ... 2nd area | region 64 ... Dichroic mirror 71, 81 ... Illuminating device.

Claims (15)

A substrate,
A wavelength conversion layer provided on one surface of the substrate,
The wavelength conversion layer includes a light emitter layer that has a light emitter that emits light when irradiated with excitation light; and
A metal film provided on the one surface of the substrate;
A plurality of wavelength conversion particles at least partially in contact with the metal film,
The wavelength converting particles are:
Metal nanoparticles,
A dielectric layer covering the surface of the metal nanoparticles;
A phosphor that is contained in the dielectric layer and emits light when irradiated with the excitation light;
A wavelength conversion element comprising:   The wavelength conversion element according to claim 1, wherein the light emitter included in the light emitter layer and the light emitter included in the wavelength conversion particle emit light in the same wavelength region.   The wavelength conversion element according to claim 1, wherein the light emitter included in the light emitter layer and the light emitter included in the wavelength conversion particle emit light in different wavelength ranges.   The distance from the interface on the opposite side to the interface with the substrate in the metal film to the center of the wavelength conversion particle is 1/2 or less of the particle diameter of the wavelength conversion particle. The wavelength conversion element as described in any one of.   2. The wavelength conversion element according to claim 1, wherein the plurality of wavelength conversion particles are arranged in one layer with a part of the wavelength conversion particles embedded in the metal film.   The wavelength conversion element according to claim 1, wherein the phosphor layer includes metal nanoparticles.   The material of the metal nanoparticles includes any of gold, silver, aluminum, platinum, and copper, and the metal nanoparticles are composed of a sphere or rod made of a single metal, a dielectric sphere coated with metal, two pieces The wavelength conversion element according to claim 1, comprising any of the above-described aggregates of particles.   2. The wavelength conversion element according to claim 1, wherein an area occupation ratio of the plurality of wavelength conversion particles per unit area of the metal film is 0.3 or more and 0.9 or less.   The wavelength conversion element according to claim 1, further comprising a wavelength selection unit that reflects or transmits the excitation light and transmits or reflects the light. The metal film has a first region and a second region in which the transmittance of the excitation light is larger than the first region,
The region where the wavelength converting particles are present overlaps the first region and the region where the wavelength converting particles are not present overlaps the second region when the metal film is viewed from the normal direction. The wavelength conversion element as described in 2. An excitation light source unit for emitting the excitation light;
A light-emitting device comprising the wavelength conversion element according to claim 1.   The light emitting device according to claim 11, wherein the excitation light is incident from a surface of the wavelength conversion layer on the metal film side, and the light is emitted from a surface of the wavelength conversion layer opposite to the metal film. .   The said excitation light injects from the surface on the opposite side to the said metal film of the said wavelength conversion layer, The said light inject | emits from the surface on the opposite side to the said metal film of the said wavelength conversion layer. Light-emitting device.   A display device comprising the light emitting device according to claim 11.   A lighting device comprising the light emitting device according to claim 11.

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