JP2014029928A - Phosphor substrate, light emitting device using the same, display device, lighting device, and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently radiate light emitted from a phosphor layer to the exterior.SOLUTION: A phosphor layer 102 is composed of a number of phosphor particles 103 made of a phosphor material and gaps 104 respectively maintained at areas between the phosphor particles 103. Adhesive layers (members) 106, which cause the phosphor particles 103 to adhere to each other, are formed in at least parts of portions of the phosphor particles 103 which contact with each other.

Description

  The present invention relates to a phosphor substrate, a light emitting device, a display device, a lighting device, and a solar cell module that can efficiently emit light emitted from a phosphor layer to the outside.

  In recent years, the need for flat panel displays (FPDs) has increased with the advancement of sophistication in society. As a problem of flat panel displays, there is a demand for higher light utilization efficiency. In order to achieve high efficiency of light utilization, for example, an excitation light source in the ultraviolet to near-ultraviolet wavelength region and a liquid crystal pixel with a TFT active matrix configuration are used to pass the excitation light and be arranged to face the pixel. There is known a liquid crystal display module that emits light by irradiating the phosphor with ultraviolet rays (see, for example, Patent Documents 1 and 2).

In addition, an illumination device that emits light from the blue range to the blue-green range, and a color filter that cuts red light, green light, and light from the blue range other than the blue-green range using the light from the blue range to the blue-green range as excitation light Are known (see, for example, Patent Documents 3, 4, and 5).

JP 60-50578 A Japanese Patent Laid-Open No. 7-253576 JP 2000-131683 A JP 2006-309225 A JP 2008-10298 A

In the display devices described in Patent Documents 1 to 5 described above, the liquid crystal display element functions as an optical shutter that selectively allows excitation light to pass therethrough, and display is performed by fluorescence of a phosphor disposed in a pixel through which excitation light has passed. . The fluorescent color is determined by the characteristics of the phosphor, and each of the red, green, and blue colors can be displayed vividly. Therefore, there is no light absorption by the color filter, and an improvement in light utilization efficiency can be expected.
The phosphor layer of the phosphor substrate in the display devices described in Patent Documents 1 to 5 is formed by dispersing or dissolving the phosphor in a binder material such as a resin.

  However, since the refractive index of the substrate material (glass substrate or the like) and the binder resin are generally close, the difference between the incident angle θi and the refractive angle θr is small at the phosphor layer and the substrate interface. On the other hand, since there is a large difference in refractive index at the interface between the substrate and air (outside air), light emitted at an angle larger than the total reflection angle determined by the difference in refractive index between the two is totally reflected and guided through the substrate. The emitted light could not be efficiently emitted outside the substrate.

 In addition, when the phosphor substrate is used as a display device, the phosphor is dispersed in the resin to constitute the phosphor layer, so that light emitted from the phosphor layer is refracted between the substrate and air (outside air). There is a problem in that the light emission reflected at the rate interface enters the adjacent pixel, the light emission is observed from the pixel that should not emit light originally, and the display quality deteriorates, for example, color blur occurs.

  The present invention has been made to solve the above-described problems, and is a phosphor substrate, a light-emitting device, a display device, a lighting device, and the like that can efficiently emit light emitted from the phosphor layer to the outside. And it aims at providing a solar cell module.

In order to solve the above problems, some aspects of the present invention provide the following phosphor substrate, and a light emitting device, a display device, a lighting device, and a solar cell module using the phosphor substrate.
That is, the phosphor substrate of the present invention includes a light transmissive substrate, a phosphor layer formed on one surface of the substrate, a wavelength selection film formed on the phosphor layer,
A phosphor substrate comprising at least
The phosphor layer emits light by excitation light,
The phosphor layer includes a large number of phosphor particles and voids maintained between the phosphor particles.

  The excitation light has a wavelength range of 400 nm to 1500 nm.

  The average dimension of the voids is greater than or equal to the dominant wavelength of light emitted from the phosphor layer.

  The gap is filled with a low refractive medium.

  The low refractive medium is a gas.

  The gas is air, nitrogen, argon, or a mixed gas thereof.

  A member made of a material different from that of the phosphor particles is disposed in the gap.

  A partition that rises from one surface of the substrate and surrounds a side surface in the thickness direction of the phosphor layer is further formed, and at least a region of the partition facing the phosphor layer has light scattering or light reflectivity. Features.

  The partition wall divides the phosphor layer into a plurality of regions.

  The phosphor particles are composed of a plurality of types of phosphor particles made of mutually different phosphor materials, and the emission main wavelength of the first phosphor particles is 500 to 560 nm among the plurality of types of phosphor particles. It is characterized by.

  Of the plurality of regions, only the first phosphor particles are accommodated in the first region.

  Said 1st fluorescent substance particle consists of several types of fluorescent substance particles from which emission main wavelengths mutually differ in the range of 500-560 nm.

  Between the said board | substrate and the said fluorescent substance layer in said 1st division, it has the maximum value of the transmittance | permeability in the wavelength range of 500-560 nm, and also the transmittance | permeability of the light of the wavelength range of 500-560 nm is 430- It is further characterized by further comprising a filter layer having a larger transmittance than that of light in each wavelength region of 490 nm and 600 to 650 nm.

  The phosphor particles are composed of a plurality of types of phosphor particles made of different phosphor materials, and among the plurality of types of phosphor particles, the emission main wavelength of the second phosphor particles is 600 to 650 nm. It is characterized by.

  Of the plurality of regions, the second compartment contains only the second phosphor particles.

  Between the said board | substrate and the said fluorescent substance layer in said 2nd division, it has the maximum value of the transmittance | permeability in the wavelength range of 600-650 nm, and also the transmittance | permeability of the light of the wavelength range of 600-650 nm is 430-300. It is further characterized by further comprising a filter layer that is larger than the maximum transmittance of light in each wavelength region of 490 nm and 500 to 560 nm.

  The phosphor particles are composed of a plurality of types of phosphor particles made of different phosphor materials, and among the plurality of types of phosphor particles, the emission main wavelength of the third phosphor particles is 430 to 490 nm. It is characterized by.

  Of the plurality of regions, the third region contains only the third phosphor particles.

  Between the said board | substrate and the said fluorescent substance layer in said 3rd division, it has the maximum value of the transmittance | permeability in the wavelength range of 430-490 nm, and also the transmittance | permeability of the light of the wavelength range of 430-490 nm is 500- It is further characterized by further comprising a filter layer that is larger than the maximum transmittance of light in each wavelength region of 560 nm and 600 to 650 nm.

  The phosphor particles are composed of a plurality of types of phosphor particles made of different phosphor materials, and among the plurality of types of phosphor particles, the emission main wavelength of the fourth phosphor particles is 560 to 590 nm. It is characterized by.

  Of the plurality of regions, the fourth compartment contains only the fourth phosphor particles.

  The phosphor layer is formed between the substrate and the wavelength selection film, and the wavelength selection film transmits the excitation light and reflects the light emission.

The phosphor substrate of the present invention comprises at least a light-transmitting substrate, a phosphor layer formed on one surface of the substrate, and a wavelength selection film formed on the phosphor layer. A phosphor substrate,
The phosphor layer emits light by excitation light,
The wavelength selective film transmits the excitation light and reflects the emission;
A phosphor substrate having a light emission extraction efficiency of 55% or more by which light emitted from the phosphor layer is transmitted through and extracted from the substrate.
The phosphor layer includes a large number of phosphor particles and voids maintained between the phosphor particles.

  The excitation light has a wavelength range of 400 nm to 1500 nm.

  A light-emitting device of the present invention includes the phosphor substrate described in each of the above items and a light source that emits the excitation light.

  The light source is an LED element.

  The light source is an organic EL element.

  A liquid crystal layer for controlling the incidence of the excitation light is further disposed between the phosphor substrate and the light source.

  A display device according to the present invention includes the light-emitting device described in each item.

  The illuminating device of this invention was equipped with the light-emitting device as described in said each item.

  A solar cell module according to the present invention includes the phosphor substrate described in each of the above items and a photoelectric conversion element.

  The solar cell module is characterized in that a peak wavelength of an emission spectrum of the phosphor layer is shorter than a wavelength of light that maximizes a photoelectric conversion efficiency of the photoelectric conversion element.

  According to the present invention, it is possible to provide a phosphor substrate, a light emitting device, a display device, a lighting device, and a solar cell module capable of efficiently emitting light emitted from the phosphor layer to the outside.

It is sectional drawing which shows the phosphor substrate of 1st Embodiment of this invention. It is sectional drawing which shows the effect | action of this invention and the conventional phosphor substrate. It is explanatory drawing which shows the measuring method of a space | gap dimension. It is an image which shows the effect of the present invention and the conventional phosphor substrate. It is sectional drawing which shows the fluorescent substance substrate of 2nd Embodiment of this invention. It is a graph which shows an example of the emission spectrum of a green fluorescent substance particle, and the transmission spectrum of a green filter. It is sectional drawing which shows the fluorescent substance substrate of the modification of 2nd Embodiment of this invention. It is sectional drawing which shows the fluorescent substance substrate of 3rd Embodiment of this invention. It is sectional drawing which shows the light-emitting device of 4th Embodiment of this invention. It is sectional drawing which shows the light-emitting device of the modification of 4th Embodiment of this invention. It is sectional drawing which shows the solar cell module of 5th Embodiment of this invention. It is a graph which shows the relationship with the photoelectric conversion efficiency with respect to the wavelength of the light in a solar cell element. It is a graph which shows the effect which applied the fluorescent substance substrate to the solar cell. It is a graph which shows the component which a red fluorescent substance absorbs among the absorption spectrum of a red fluorescent substance, an emission spectrum, the spectrum of sunlight, and the spectrum of sunlight. It is a graph which shows the light power conversion efficiency of the component which a red fluorescent substance absorbs among the emission spectrum of a red fluorescent substance, the spectrum of sunlight, and a crystalline silicon solar cell. It is a graph which shows the component which a red fluorescent substance absorbs among the absorption spectrum of the red fluorescent substance of another structure, an emission spectrum, the spectrum of sunlight, and the spectrum of sunlight. It is a graph which shows the light power conversion efficiency of the component which a red fluorescent substance absorbs among the emission spectrum of the red fluorescent substance of another structure, and the spectrum of sunlight, and a GaAs solar cell. It is a graph which shows the main transmissive wavelength range of a color filter. It is a top view which shows the display apparatus of this invention. It is a perspective view which shows the illuminating device of this invention.

  Hereinafter, a phosphor substrate, a light emitting device, a display device, a lighting device, and a solar cell module according to the present invention will be described with reference to the drawings. The following embodiments are specifically described for better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified. In addition, in the drawings used in the following description, in order to make the features of the present invention easier to understand, there is a case where a main part is shown in an enlarged manner for the sake of convenience. Not necessarily.

[First Embodiment]
The first embodiment of the present invention will be described below.
FIG. 1 is a schematic cross-sectional view showing the phosphor substrate of the first embodiment.
The phosphor substrate 100 according to the present embodiment includes a light-transmitting substrate 101 and a phosphor layer 102 that is disposed on one surface 101 a of the substrate 101. In the phosphor substrate 100, the side opposite to the surface facing the substrate 101 of the phosphor layer 102 is an excitation light incident surface Ef on which the excitation light FL that excites the phosphor layer 102 is incident.

  The excitation light FL may be emitted by an excitation light source (not shown) such as a blue LED. The excitation light FL is incident on the phosphor layer 102 from the excitation light incident surface Ef, thereby exciting the phosphor layer 102. Is emitted. As the excitation light FL, light having a wavelength of 400 nm or more longer than the near ultraviolet region is used. The phosphor layer 102 is excited by such excitation light having a wavelength of 400 nm or more.

  Further, it is preferable that a band pass filter layer 105 is further formed on the excitation light incident surface Ef of the phosphor layer 102. The band-pass filter layer 105 transmits the excitation light FL and reflects the light emitted from the phosphor layer 102 by the excitation light FL.

  The phosphor layer 102 is composed of a large number of phosphor particles 103 made of a phosphor material and voids 104 held between the phosphor particles 103. Further, an adhesive layer (member) 106 that adheres the phosphor particles 103 to each other is formed on at least a part of the portion where the phosphor particles 103 are in contact with each other.

  The phosphor particles 103 may be formed in a spherical or irregular shape regardless of whether they are organic phosphors or inorganic phosphors. The phosphor particles 103 are the same even if they have different shapes. It may be a shape. In addition, the phosphor particles 103 may have different dimensions or the same dimensions.

Hereinafter, although the constituent material examples of each element constituting the phosphor substrate 100 of the present embodiment are listed, the present invention is not limited to these.
Since the light-transmitting substrate 101 needs to take out the light emitted from the phosphor particles from the fluorescence emission surface Ff of the substrate 101, the substrate 101 needs to be transparent to the light emission from the phosphor particles. There is. For example, an inorganic material substrate made of glass, quartz or the like, a plastic substrate made of polyethylene terephthalate, polycarbazole, polyimide, or the like can be given.

  Various types of adhesives can be used as the type of adhesive constituting the adhesive layer (member) 14, and examples thereof include silicic acid polymerization (Si—O—Si—crosslinking), phosphoric acid bonding (PO— Examples thereof include an adhesive using P-). An adhesive using PVA (polyvinyl alcohol) can also be used.

  The bandpass filter layer 15 preferably has a characteristic of transmitting only the wavelength of the excitation light. For example, when the wavelength of the excitation light is blue (wavelength 450 nm), light in the blue region (light in the wavelength range of 435 to 480 nm) is transmitted and light from green to the near infrared region (wavelength in the blue region). It has a function of reflecting light outside the range. For example, it may be composed of a thin film such as gold or silver, or a dielectric multilayer film.

  As the phosphor material constituting the phosphor particle 103, in the case of an organic phosphor material, as a blue fluorescent dye, for example, stilbenzene dye: 1,4-bis (2-methylstyryl) benzene, trans-4, 4'-diphenylstilbenzene, coumarin dye: 7-hydroxy-4-methylcoumarin, 2,3,6,7-tetrahydro-11-oxo-1H, 5H, 11H- [1] benzopyrano [6,7,8 -Ij] ethyl quinolidine-10-carboxylate (coumarin 314), 10-acetyl-2,3,6,7-tetrahydro-1H, 5H, 11H- [1] benzopyrano [6,7,8-ij] quinolidine- 11-one (coumarin 334), anthracene dyes: 9,10 bis (phenylethynyl) anthracene, perylene and the like.

  In addition, as a green fluorescent dye of an organic phosphor material, for example, a coumarin dye: 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), 10- (benzothiazole -2-yl) -2,3,6,7-tetrahydro-1H, 5H, 11H- [1] benzopyrano [6,7,8-ij] quinolizin-11-one (coumarin 545), coumarin 545T, coumarin 545P , Naphthalimide dyes: basic yellow 51, solvent yellow 11, solvent yellow 98, solvent yellow 116 Solvent Yellow 43, Solvent Yellow 44, Perylene dyes: Lumogen Yellow, Lumogen Green, Solvent Green 5, fluorescein dye, azo dye, phthalocyanine dye, anthraquinone dye, quinacridone dye, isoindolinone dye, Examples include thioindigo dyes and dioxazine dyes.

  Examples of red fluorescent dyes for organic phosphor materials include cyanine dyes: 4-dicyanomethylene-2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM), DCM-2. DCJTB, pyridine dye: 1-ethyl-2- [4- (p-dimethylaminophenyl) -1,3-butadienyl] -pyridinium-perchlorate (pyridine 1), and xanthene dye: rhodamine B, rhodamine 6G , Rhodamine 3B, rhodamine 101, rhodamine 110, basic violet 11, sulforhodamine 101, basic violet 11, basic red 2, perylene dye: lumogen orange, lumogen pink, rumogen red, solvent orange 55, oxazine dye, chrysene dye, Thiofurabi Dye, pyrene dye, anthracene dye, acridone dye, acridine dye, fluorene dye, terphenyl dye, ethene dye, butadiene dye, hexatriene dye, oxazole dye, coumarin dye, stilbene And dyes such as di- and triphenylmethane dyes, thiazole dyes, thiazine dyes, naphthalimide dyes and anthraquinone dyes.

  When an organic phosphor material is used as each color phosphor, it is desirable to use a dye that is not easily degraded by blue light, ultraviolet light, or external light of the backlight. In this respect, it is particularly preferable to use a perylene dye having excellent light resistance and a high quantum yield.

In the case of an inorganic phosphor material, as a blue phosphor, Sr ₂ P ₂ O ₇ : Sn ₄ +, Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , SrGa ₂ S ₄ : Ce ³⁺ , CaGa ₂ S ₄ : Ce ³⁺ , (Ba, Sr) (Mg, Mn) Al ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ca, Ba ₂ , 0 Mg) ₁₀ (PO ₄ ) _{6 Cl 2} : Eu ²⁺ , BaAl ₂ SiO ₈ : Eu ²⁺ , Sr ₂ P ₂ O ₇ : Eu ²⁺ , Sr ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , (Sr, Ca, Ba) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , BaMg ₂ Al ^{_{16 O 27: Eu 2+, (}} Ba, Ca) 5 (PO 4) 3 Cl: Eu 2+, Ba 3 MgSi 2 O 8: Eu 2+, Sr 3 MgSi 2 O 8: Eu 2+ , etc. And the like

In addition, as the green phosphor of the inorganic phosphor material, (BaMg) Al ₁₆ O ₂₇ : Eu ²⁺ , Mn ²⁺ , Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ , (SrBa) Al ₁₂ Si ₂ O ₈ : Eu ²⁺ , (BaMg) ₂ SiO ₄ : Eu ²⁺ , Y ₂ SiO ₅ : Ce ³⁺ , Tb ³⁺ , Sr ₂ P ₂ O ⁷ -Sr ₂ B ₂ O ₅ : Eu ²⁺ , (BaCaMg) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , Sr ₂ Si ₃ O ₈ -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⁺ , (BaS ^{_{) SiO 4: Eu 2+, (}} Si, Al) 6 (O, N) 8: Eu 2+, Ca 3 (Sc, Mg) 2 Si 3 O 12: Ce 3+, SrSi _{(O, Cl) 2 N 2} : Eu 2+ and the like.

As red phosphors of inorganic phosphor materials, Y ₂ O ₂ S: Eu ³⁺ , YAlO ₃ : Eu ³⁺ , Ca ₂ Y ₂ (SiO ₄ ) ₆ : Eu ³⁺ , LiY ₉ (SiO ₄ ) ₆ O ₂ : Eu ³⁺ , YVO ₄ : Eu ³⁺ , CaS: Eu ³⁺ , Gd ₂ O ₃ : Eu ³⁺ , Gd ₂ O ₂ S: Eu ³⁺ , Y (P, V) O ₄ : Eu ³⁺ , Mg ₄ GeO ₅ . 5F: 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 , (Sr, Ca) AlSiN ₃ : Eu ²⁺ , CaAlSiN ₃ : Eu ²⁺ , SrSiN ₂ : Eu ²⁺ , SrAlSiN ₃ : Eu ²⁺ , Ca ₂ Si ₅ N ₈ : Eu ²⁺ , Sr ₂ Si ₅ N ₈ : Eu ²⁺ , Ba ₂ AlSi ₅ N ₈ : Eu ²⁺ , Sr ₂ Si ₃ O ₂ N ₄ : Eu ²⁺ , Sr ₂ Si ₃ Al ₂ O ₂ N ₆ : Eu ²⁺ , SrSc ₂ O ₄ : Eu ²⁺ , (Sr, Ba) ₃ SiO ₅ : Eu ²⁺ , Mg ₂ TiO ₄ : Mn ^{2+ and the} like.

  The inorganic phosphor material may be subjected to a surface modification treatment as necessary. The method may be a chemical treatment such as a silane coupling agent or a physical treatment by adding submicron order particles. And those using a combination thereof. In consideration of stability such as deterioration due to excitation light and deterioration due to light emission, it is generally preferable to use an inorganic material.

In the case of inorganic phosphors, these phosphors generally have a refractive index = 1.8 or higher. For example, the refractive index of YAG: Ce, TAG: Ce, Al ₂ O ₃ : Ce is about 1.8. In the case of organic phosphors, those having a high refractive index of about 1.7 or more are generally used. For example, the refractive index of C ₂₀ H ₁₈ N ₂ O ₂ S (coumarin 6) is about 1.69.

  The average particle diameter (d50) of the phosphor particles 103 is preferably about 1 μm to 20 μm regardless of whether the phosphor is an inorganic phosphor or an organic phosphor. If the average particle size is 1 μm or less, the luminous efficiency of the phosphor layer 11 may be rapidly reduced. If the particle size is small, the excitation light cannot be sufficiently absorbed. In addition, it is assumed that the average void size also decreases with the particle size, and if the average void size is smaller than the emission main wavelength, the light extraction efficiency from the phosphor layer may be reduced.

  On the other hand, when the average particle diameter (d50) of the phosphor particles 103 is 20 μm or more, there are the following problems. First, for a phosphor film formed on a transparent substrate, a structure in which the phosphor is excited by an excitation light source from the phosphor film side and light emitted from the phosphor layer is extracted through the transparent substrate is defined as a transmissive phosphor substrate Then, when a large number of phosphor particles are stacked, light emitted from the phosphor particles on the excitation light side of the phosphor layer is reflected and scattered by the phosphor particles on the substrate side of the phosphor layer. It is interrupted by. That is, the light extraction efficiency from the phosphor layer is reduced.

On the other hand, when the phosphor particles are not sufficiently stacked, the phosphor layer cannot absorb the excitation light sufficiently, so the amount of light emitted from the phosphor layer is decreased, and as a result, the amount of light emitted from the phosphor layer is decreased. Let
Therefore, in the case of a transmissive phosphor substrate, the extraction efficiency is most improved when 3 to 4 phosphor particle layers are stacked in relation to the film thickness described later.

When the average particle diameter of the phosphor particles is 20 μm or more, when 3 to 4 particle layers are laminated, the layer thickness of the phosphor layer becomes 60 to 80 μm, which increases the number of materials and leads to an increase in material cost. In addition, when a display device application is assumed, it becomes difficult to perform patterning at a high resolution.
For example, when considering a 60-inch FHD (1920 × 1080 pixels) RGB three-color display device, the size of each pixel of RGB is about 210 × 210 μm. When the average particle diameter of the phosphor particles is 20 μm or more, the number of phosphor particles arranged on one plane without any gap is 10 × 10 or less.

  Considering a 40 inch FHD (1920 × 1080 pixels) RGB three-color display device, the size of each RGB pixel is about 130 × 130 μm. When the average particle diameter of the phosphor particles is 20 μm or more, the number of phosphor particles arranged in a single plane without a gap is 6 × 6 or less.

  In the case of limiting to a display device, it is very difficult to apply to a region that is not sufficiently wide with respect to the phosphor particles in view of a method of applying the phosphor particles to a desired pixel position described later. When the coating amount is large, the phosphor layer protrudes easily from the pixel, and as will be described later, the film thickness becomes unnecessarily thick and the light extraction efficiency decreases. On the contrary, when the coating amount is small, a region in which the phosphor particles in the phosphor layer are sparse occurs. Therefore, there is a possibility that sufficient quality in the display device cannot be ensured.

  The film thickness of the phosphor layer 102 is usually about 100 nm to 100 μm, but preferably 1 μm to 100 μm. If the thickness of the phosphor layer 102 is less than 100 nm, it becomes difficult to sufficiently absorb the excitation light emitted from the light source, so that the emission efficiency is lowered, and the transmitted light of the excitation light is mixed with the required color. Problems such as deterioration of color purity arise. Further, in order to increase the absorption of light emitted from the light source and reduce the transmitted light of the excitation light to such an extent that the color purity is not adversely affected, the film thickness is preferably 1 μm or more. Further, if the thickness of the phosphor layer 102 exceeds 100 μm, the light emitted from the light source is already sufficiently absorbed. Therefore, the efficiency is not increased, but only the material is consumed and the material cost is increased.

  The film thickness of the phosphor layer 102 is further preferably 1 μm to 80 μm. The reason is that a particle size (1 to 20 μm) × 3,4 particle layer is preferable. However, it is also preferable to set a more limited film thickness range according to the light absorption coefficient and particle size of the phosphor. The reason is as follows.

  Comparing the organic phosphor and the inorganic phosphor, the organic phosphor generally has a higher absorption coefficient. Therefore, since organic phosphors can sufficiently absorb excitation light even when the particle size is small and the phosphor layer thickness is small compared to inorganic phosphors, organic phosphors are better than inorganic phosphors. A preferable particle size range and film thickness range are set in the range of small particle size and small film thickness. Thus, it is preferable to set a more limited film thickness range according to the light absorption coefficient and particle size of the phosphor.

  A gap 104 formed between the phosphor particles 103 is filled with a low refractive medium. The low refractive medium may be a gas, and examples thereof include air, nitrogen, argon, or a mixed gas thereof.

The gap 104 may be a vacuum. For example, low vacuum according to JIS standard: degree of vacuum is 100 Pascal or higher, medium vacuum: degree of vacuum is 0.1 to 100 Pascal, high vacuum: degree of vacuum is 10 ^{−5 to} 0.1 Pascal, ultrahigh vacuum: degree of vacuum is Any vacuum state such as 10 ⁻⁵ Pascal or less may be used.

  As a method of forming the void 104 filled with such a low refractive medium, a dispersion liquid for forming a phosphor layer containing the phosphor particles 103 and an adhesive constituting the adhesive layer (member) 106 is prepared, and the substrate 10 is formed. It is applied on one surface 10a. Thereafter, the dispersion is volatilized by heat treatment at 400 to 500 ° C./1 hour, and voids 104 as shown in FIG. 1 are formed in the volatilized portion.

  An example of a method for forming the gap 13 filled with such a low refractive medium will be given. First, a phosphor layer forming dispersion liquid containing phosphor particles 12, a thermally decomposable resin that is a raw material of a member constituting the adhesive layer (member) 14, and a solvent is prepared, and is formed on one surface 10 a of the substrate 10. Apply. Thereafter, heat treatment volatilizes the solvent in the dispersion liquid, decomposes the thermally decomposable resin in the dispersion liquid, and reduces the volume, thereby forming voids 13 between the phosphors. In addition, the resin component that remains slightly between the phosphor particles serves as an adhesive and becomes the adhesive member 14.

In the case of an inorganic phosphor, the heat treatment temperature is preferably 400 to 500 ° C./about 1 to 3 hours from the viewpoint of heat resistance of the phosphor. On the other hand, in the case of an organic phosphor, the heat resistance is generally 200 ° C. or lower, and therefore, the heat treatment temperature of the organic phosphor is desirably 200 ° C. or lower. Therefore, it is desirable to use a decomposition temperature of the thermally decomposable resin used for the organic phosphor of 200 ° C. or less.
In the case of an organic phosphor, a phosphor film can be formed as organic phosphor particles after heat treatment by dispersing in an insoluble solvent.

  As a method for applying the dispersion liquid for forming the phosphor layer to the substrate 101, 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 A known wet process such as a printing method such as a printing method, a screen printing method or a micro gravure coating method can be preferably employed.

The concept of the gap 104 in the phosphor layer 102 will be described with an example of a method for measuring the gap dimension.
FIG. 3A is a scanning electron microscope image (SEM image) of the cross section of the phosphor layer 102. The cross section of the phosphor layer 102 is obtained by cleaving the phosphor substrate 1 perpendicular to the thickness direction of the phosphor layer 102. As the scanning electron microscope, model number SU8020 manufactured by Hitachi High-Tech was used. However, the scanning electron microscope is not limited as long as it is a scanning electron microscope having equivalent performance.

In addition, an SEM image obtained from 90 ° perpendicular to the cross section shown in FIG. 3A at the same location as FIG. 3A and taken from above the thickness direction of the phosphor layer 102 is also acquired.
The phosphor region and the void region at the cross-sectional position are defined from the SEM image captured from 90 ° perpendicular to FIG. 3 (a) and FIG. 3 (a). FIG. 3B is a diagram in which the phosphor region is defined. The phosphor region 901 is surrounded by a black line. FIG. 3C binarizes the phosphor region and the void region at the above-described cross-sectional position, and shows the phosphor region 902 in black and the void region 903 in white.

  Then, a circular area 904 indicated by a dotted line is filled so as to fill the void area defined in FIG. At this time, the large circular area 904 is filled first, and then the small circular area 904 is filled. FIG. 3D shows a state in which the circular region 904 indicated by the dotted line is filled in this way. The diameter of each circular region 904 illustrated in FIG. 3D is defined as the dimension of the gap 104 in the phosphor substrate (phosphor layer 102).

The frequency distribution is obtained by measuring the dimensions of the plurality of gaps 104. The median value obtained from the frequency distribution (median) is defined as the average dimension of the air gap 104.
The cross-sectional SEM images of the five phosphor layers 102 were taken by the measurement method described above, and the frequency distribution was obtained by measuring the dimensions of a total of 50 voids 104. The average dimension of the air gap 104 defined by the median value (median) obtained from the frequency distribution was about 12 μm.

The operation of the phosphor substrate of the present embodiment having the above configuration will be described in comparison with conventional phosphor substrates (Conventional Example 1 and Conventional Example 2).
FIG. 2A is a cross-sectional view showing the operation of the phosphor substrate of Conventional Example 1. FIG.
FIG. 2B is a cross-sectional view showing the operation of the phosphor substrate of Conventional Example 2.
FIG. 2C is a cross-sectional view showing the operation of the phosphor substrate of the present embodiment.
FIG. 2A: As shown in Conventional Example 1, the phosphor substrate 200 has a phosphor layer 202 formed on one surface of a transparent substrate 201, and this phosphor layer 202 is inorganic in the sealing resin 204. The phosphor 203 is dispersed. A wavelength selection layer 205 is formed on the phosphor layer (on the opposite side of the transparent substrate 201).
SrSi ₂ (O, Cl) ₂ N ₂ : Eu ²⁺ was used for the inorganic phosphor layer 203. Polystyrene was used for the sealing resin 204. The particle size of the inorganic phosphor 203 (SrSi ₂ (O, Cl) ₂ N ₂ : Eu ²⁺ ) was about 15 μm. The thickness of the phosphor layer 202 was about 45 μm.

FIG. 2B: As shown in Conventional Example 2, the phosphor substrate 200 has a phosphor layer 202 formed on one surface of a transparent substrate 201, and this phosphor layer 202 is organic in a sealing resin 204. The phosphor 203 is dissolved. A wavelength selection layer 205 is formed on the phosphor layer (on the opposite side of the transparent substrate 201). Coumarin 6 was used for the organic phosphor layer 203. Polystyrene was used for the sealing resin 204.
The film thickness of the phosphor layer 202 was about 27 μm.

FIG. 2 (c): As shown in this embodiment, the phosphor substrate 100 has a phosphor layer 102 formed on one surface of a transparent substrate 101, and the phosphor layer 102 is composed of a plurality of phosphor particles. A void 104 is formed between the phosphor particles. The air gap 104 is filled with air. A wavelength selection layer 105 is formed on the phosphor layer (on the opposite side of the transparent substrate 101). SrSi ₂ (O, Cl) ₂ N ₂ : Eu ²⁺ was used for the inorganic phosphor layer 103.
The particle size of the inorganic phosphor 103 (SrSi ₂ (O, Cl) ₂ N ₂ : Eu ²⁺ ) was about 15 μm. The film thickness of the phosphor layer 102 was about 48 μm.

  In the configuration of the conventional phosphor substrate 200 shown in FIG. 2A, an angle smaller than the total reflection angle determined by the difference in refractive index at the interface 201b between the transparent (glass) substrate 101 and air (outside air) Ar. The fluorescent light 207a having is taken out to the air side. On the other hand, the light emission 207 b and the light emission 208 having an angle larger than the total reflection angle determined by the refractive index difference are totally reflected and guided through the transparent (glass) substrate 101. Therefore, the emitted light cannot be efficiently extracted outside the substrate.

  Further, the light emission 207b totally reflected at the interface 201b and a part of the light emission 207b of the light emission 208 enter the phosphor layer 202 again after total reflection, and are scattered by the inorganic phosphor 203, and the reflection angle is changed again. It enters the interface 201b at an angle smaller than the total reflection angle and is taken out to the air side.

  In the configuration of the conventional phosphor substrate 200 shown in FIG. 2B, an angle smaller than the total reflection angle determined by the difference in refractive index at the interface 201b between the transparent (glass) substrate 101 and air (outside air) Ar. The light emission 207 having is taken out to the air side. On the other hand, the light emission 209 having an angle larger than the total reflection angle determined by the refractive index difference is totally reflected and guided through the transparent (glass) substrate 101 and the phosphor layer 202. In the conventional example 2 shown in FIG. 2B, the organic phosphor is dissolved in the phosphor layer 202, and the light guided through the phosphor layer 202 is not scattered. Therefore, the light emission 209 once totally reflected at the interface 201b is guided between the interface 201b and the wavelength selection layer 205 and is not extracted outside the substrate.

  In the configuration of the phosphor substrate 100 of the present embodiment shown in FIG. 2C, the light emission 107 emitted from the phosphor particles once enters the gap 104 and then enters the transparent (glass) substrate 101. It is obvious that such light emission 107 is always smaller than the total reflection angle at the interface 101b with air (outside air) Ar. Therefore, the light emission 107 is always extracted outside the substrate.

  As an exception, out of the light emitted from the phosphor particles that are directly incident on the substrate 101 from the position where the phosphor particles and the substrate 101 are in contact, at the interface 101b between the transparent (glass) substrate 101 and air (outside air) Ar, The light emission 108a having an angle larger than the total reflection angle determined by the refractive index difference is guided through the substrate 101, but the ratio is very small.

  Therefore, the fluorescence 107 incident on the substrate 101 from the gap 104 can be emitted from the substrate 101 toward the air (outside air) Ar. Thereby, in the phosphor substrate 100 of the present embodiment, it is possible to emit more light emitted from the phosphor layer toward the air (outside air) Ar as compared with the conventional phosphor substrate 200. It becomes possible to increase the fluorescence emission efficiency of the phosphor substrate.

Table 1 shows measurement results obtained by measuring the external extraction efficiency of light emission in the above-described conventional example 1 (FIG. 2A), conventional example 2 (FIG. 2B), and the present embodiment (FIG. 2C). Show. The measurement was performed according to the following procedure.
A. A phosphor substrate is placed in an integrating sphere of a total luminous flux measurement system (integrated hemisphere QE-1100 manufactured by Otsuka Electronics Co., Ltd.), and the total light emission amount is measured.
B. Next, the phosphor substrate is attached to a window of the same size as the phosphor substrate provided in the integrating sphere QE-1100 in such a direction that the light transmitted through the substrate enters the integrating sphere, and the amount of light transmitted through the substrate. Measure.
C. The extraction efficiency is defined as A / B.

  According to Table 1 showing the measurement results of the external extraction efficiency of light emission, the external extraction efficiency of light emission is 54% in the configuration of Conventional Example 1 and 25% in the configuration of Conventional Example 2, whereas In the embodiment, it was confirmed that the external extraction efficiency of 80%, which is very high emission, can be realized.

In addition, the phosphor substrate of this embodiment has an effect of reducing bleeding of emitted light.
FIG. 4 is a photograph showing the operation of the present embodiment and the conventional phosphor substrate.
4A shows the conventional phosphor substrate shown in FIG. 2A, and FIG. 4B shows the state of light emission of the phosphor substrate of this embodiment shown in FIG. 2C from the transparent substrate side. It is a photograph taken. Using a blue LED with an emission wavelength of 450 nm and a 5 mm square mask window as an excitation light source, only the central 5 mm square was irradiated from the wavelength selection film (bandpass filter) side.

  In the conventional phosphor substrate shown in FIG. 2 (a), the ratio of the component of emitted light that is guided through the substrate is large, and a part of the component is scattered by the substrate. Outside air). For this reason, as shown in FIG. 4A, although the emitted light is originally rectangular, its outline blurs and blurs.

  On the other hand, in the phosphor substrate of this embodiment shown in FIG. 2C, the fluorescence incident on the substrate from the gap can always be emitted from the substrate toward the air (outside air), so that there are few fluorescent components propagating through the substrate. For this reason, as shown in FIG.4 (b), rectangular light emission is radiate | emitted with a clear outline, almost without bleeding. Therefore, if such a phosphor substrate of this embodiment is applied to a display device, it is possible to project a clear image with little blur.

[Second Embodiment]
FIG. 5 is a schematic cross-sectional view showing a display device including the phosphor substrate according to the second embodiment.
A display device 500 according to this embodiment includes a phosphor substrate 520, an excitation light source 514, and a liquid crystal layer 515. The excitation light source 514 is a light source device that emits excitation light FL having a wavelength of 405 nm, for example. The liquid crystal layer 515 may be a known liquid crystal layer that controls the incidence of the excitation light FL on the phosphor substrate 520.

  The phosphor substrate 520 includes a light-transmitting substrate 501 and a phosphor layer 502 placed on one surface 501 a of the substrate 501. In the phosphor substrate 520, the side opposite to the surface facing the substrate 501 of the phosphor layer 502 is an excitation light incident surface Ef on which the excitation light FL that excites the phosphor layer 502 is incident.

  It is preferable that a band pass filter layer 505 is further formed on the excitation light incident surface Ef of the phosphor layer 502. The band-pass filter layer 505 transmits the excitation light FL and reflects light emitted from the phosphor layer 502 by the excitation light FL.

  The phosphor layer 502 includes a large number of phosphor particles 503 made of a phosphor material and voids 504 held between the phosphor particles 503. The gap 504 is filled with nitrogen gas. The phosphor layer 502 rises from one surface 501a of the substrate 501 and is partitioned (first to third partitions) for each predetermined region by partition walls 512 surrounding the side surfaces along the thickness direction of the phosphor layer 502. A region of the partition 512 facing at least the phosphor particles 503 has light scattering properties or light reflection properties. Further, it is preferable that a light shielding layer 511 is further formed between the bottom of each partition wall 512 and the substrate 501.

  The phosphor particles 503 are divided into green phosphor particles 503G arranged in the first compartment, red phosphor particles 503R arranged in the second compartment, and third compartments for each region divided by the partition 512. The arranged blue phosphor particles 503B are filled. Of the phosphor particles 503, the emission main wavelength (peak wavelength region) of the green phosphor particles 503G (first phosphor particles) is 500 to 560 nm. The emission main wavelength (peak wavelength range) of the red phosphor particles 503R (second phosphor particles) is 600 to 650 nm. The emission main wavelength (peak wavelength range) of the blue phosphor particles 503B (third phosphor particles) is 430 to 490 nm.

  Further, between these red phosphor particles 503R, green phosphor particles 503G, blue phosphor particles 503B and the substrate 501, a red filter 513R, a green filter 513G, which is a color filter 513 partitioned by a light shielding layer 511, respectively. A blue filter 513B is formed.

  The green filter 513G arranged in the first section has a maximum transmittance in a wavelength range of 500 to 560 nm (green light), and has a light transmittance in a wavelength range of 500 to 560 nm (green light). , 430 to 490 nm (blue light) and 600 to 650 nm (red light).

  The red filter 513R arranged in the second section has a maximum transmittance in the wavelength region of 600 to 650 nm (red light), and has a light transmittance in the wavelength region of 600 to 650 nm (red light). , 430 to 490 nm (blue light) and 500 to 560 nm (green light).

  The green filter 513B arranged in the first section has a maximum transmittance in the wavelength region of 430 to 490 nm (blue light), and has a light transmittance in the wavelength region of 430 to 490 nm (blue light). , 500 to 560 nm (green light) and 600 to 650 nm (red light).

  FIG. 18 shows a graph in which the transmission wavelength regions of the red filter 513R, the green filter 513G, and the blue filter 513B are measured. In this graph, for example, the red filter 513R is 600 to 650 nm, the green filter, with the wavelength range having the maximum transmittance centered on light in the wavelength range where the transmittance is 50% or more as the main transmission wavelength region of each filter. 513G transmits light in the wavelength range of 500 to 560 nm, and the blue filter 513B transmits light in the wavelength range of 430 to 490 nm.

  Table 2 shows the maximum transmittance (%) and the minimum transmittance (%) of red light, green light, and blue light in each filter.

  As the color filter 513, a known color filter can be used. Here, by providing the color filter, the color purity of the red pixel PR, the green pixel PG, and the blue pixel PB partitioned by the partition wall 512 can be increased, and the color reproduction range of the display device 500 can be expanded. .

FIG. 6 shows the emission spectrum of the green phosphor particles 503G (SrSi ₂ (O, Cl) ₂ N ₂ : Eu ²⁺ ) arranged in the first section and the transmission spectrum of the green filter 513G arranged in the first section. An example is shown. Although the emission spectrum of the green phosphor particles 503G has an emission peak at about 540 nm, it has a tail to a wavelength of about 650 nm and has a significant red component. However, the emission spectrum of the green phosphor particles 503G that has passed through the green filter 513G is obtained by multiplying the emission spectrum of the green phosphor particles 503G by the transmission spectrum of the green filter 513G. Can be increased.

  Further, it is absorbed by the phosphor particles 503R, 503G, and 503B by the blue filter 513B facing the blue phosphor particles 503B, the green filter 513G facing the green phosphor particles 503G, and the red filter 513R facing the red phosphor particles 503R. In addition, since the transmitted excitation light can be prevented from leaking to the outside, it is possible to prevent a decrease in color purity of light emission due to light emission from the phosphor particles 503R, 503G, and 503B and color mixture by the excitation light. .

  Further, external light (light incident from the outside of the substrate) is generated by the blue filter 513B facing the blue phosphor particles 503B, the green filter 513G facing the green phosphor particles 503G, and the red filter 513R facing the red phosphor particles 503R. Therefore, it is possible to reduce or prevent light emission of the phosphor particles 513R, 513G, and 513B in the unintended pixel due to external light, and it is possible to reduce or prevent a decrease in contrast.

  The partition 512 is made of a material containing, for example, a resin and light scattering particles. For example, it is preferable that light scattering particles having a higher refractive index than the resin are dispersed in a resin having a low refractive index. Further, in order for blue light to be effectively scattered by the light-scattering partition walls, the particle size of the light-scattering particles needs to be in the Mie scattering region. About -500 nm is preferable.

  The resin material forming the partition wall 512 is preferably a light-transmitting resin. Specific examples of the resin material include acrylic resin (refractive index: 1.49), melamine resin (refractive index: 1.57), nylon (refractive index: 1.53), polystyrene (refractive index: 1.60), Melamine beads (refractive index: 1.57), polycarbonate (refractive index: 1.57), polyvinyl chloride (refractive index: 1.60), polyvinylidene chloride (refractive index: 1.61), polyvinyl acetate (refractive) Ratio: 1.46), polyethylene (refractive index: 1.53), polymethyl methacrylate (refractive index: 1.49), poly MBS (refractive index: 1.54), medium density polyethylene (refractive index: 1. 53), high density polyethylene (refractive index: 1.54), tetrafluoroethylene (refractive index: 1.35), poly (trifluoroethylene chloride) (refractive index: 1.42), polytetrafluoroethylene (refractive index: 1.3 ), And the like.

  When an inorganic material is used as the light scattering particles constituting the partition wall 512, for example, an oxide of at least one metal selected from the group consisting of silicon, titanium, zirconium, aluminum, indium, zinc, tin, and antimony And the like.

  In the case where particles (inorganic particles) made of an inorganic material are used for the partition walls 512, for example, silica beads (refractive index: 1.44), alumina beads (refractive index: 1.63), titanium oxide beads (refractive index). Anatase type: 2.50, rutile type: 2.70), zirconia oxide beads (refractive index: 2.05), zinc oxide beads (refractive index: 2.00), barium titanate (BaTiO3) (refractive index: 2) .4).

  When particles (organic particles) made of an organic material are used for the partition walls 512, for example, polymethyl methacrylate beads (refractive index: 1.49), acrylic beads (refractive index: 1.50), acrylic-styrene Polymer beads (refractive index: 1.54), melamine beads (refractive index: 1.57), high refractive index melamine beads (refractive index: 1.65), polycarbonate beads (refractive index: 1.57), styrene beads (Refractive index: 1.60), crosslinked polystyrene beads (refractive index: 1.61), polyvinyl chloride beads (refractive index: 1.60), benzoguanamine-melamine formaldehyde beads (refractive index: 1.68), silicone beads (Refractive index: 1.50).

  By selecting an alkali-soluble resin as a constituent resin of the material of the partition wall 512 and adding a photopolymerizable monomer, a photopolymerization initiator, and a solvent, the partition wall material can be made into a photoresist, and patterned by photolithography. 512 can be formed.

  The vertical and horizontal size of the opening section (one section of the phosphor layer) partitioned by the light shielding layer 511 of the partition wall 512 is preferably about 20 μm × 20 μm to about 500 μm × 500 μm. The partition 512 preferably has a reflectance of 80% or more in the CIE 1976 L * a * b display system.

  For the purpose of improving the contrast as usual, a thin black barrier rib layer may be inserted on the light extraction direction side of the light scattering barrier 512 in comparison with the light scattering barrier of about 0.01 μm to 3 μm. Furthermore, in order to prevent excitation light designed to enter a certain pixel from leaking to adjacent pixels and causing color mixing, the light of the light-scattering partition wall is absorbed for the purpose of absorbing the light entering the adjacent pixels. A thin black barrier rib layer may be inserted on the side opposite to the take-out direction as compared with a light-scattering barrier rib of about 0.01 μm to 3 μm.

When patterning the phosphor layer 502 by a dispenser method, an ink jet method, or the like, it is essential to impart liquid repellency to the partition 512 in order to prevent the phosphor solution from overflowing from the partition 512 and mixing colors between adjacent pixels. It is. Examples of a method for imparting liquid repellency to the partition 512 include the following methods.
(1) Fluorine plasma treatment For example, as disclosed in Japanese Patent Application Laid-Open No. 2000-76979, a plasma treatment is performed on a substrate on which a partition wall is formed under a condition where the introduced gas is a fluorine-based gas, thereby repelling the partition wall. Liquidity can be imparted.
(2) Addition of fluorinated surface modifier A liquid repellency can be imparted to the partition walls by adding a fluorinated surface modifier to the light scattering partition material. As the fluorine-based surface modifier, for example, a UV curable surface modifier Defenser (manufactured by DIC Corporation), Mega Fuck, or the like can be used.

The shape of the partition wall 512 is such that the opening of the partition wall 512 is wider on the incident side than the emission side of the excitation light so that the excitation light does not enter the adjacent pixel of the pixel that should originally be incident. It is desirable.
In order to sufficiently improve the adhesion between the substrate 501 and the partition 512, the ratio of the height of the partition 512 to the lateral width of the partition 512 (aspect ratio) is preferably 1 or more.

  While the fluorescence extraction efficiency of the display device using the phosphor substrate having the conventional structure shown in FIG. 3A is 31%, according to the display device of this embodiment shown in FIG. Improved to 51%. This makes it possible to realize a bright and clear full-color display device.

[Modification of Second Embodiment]
In the display device 500 shown in FIG. 5, one type of phosphor particle 503 is arranged in each section partitioned by the partition 512, but two or more types of phosphor particles 503 are arranged in one section. You may do it. For example, in the modification of the second embodiment shown in FIG. 7, three types of green phosphor particles 503G1, 503G2, and 503G3 are arranged in the second section of the phosphor layer 502. The three types of green phosphor particles 503G1, 503G2, and 503G3 have emission main wavelengths different from each other in the emission main wavelength (peak wavelength region) range of 500 to 560 nm. The phosphor particles arranged in one section may be a plurality of types of phosphor particles having different average particle diameters.

[Third Embodiment]
FIG. 8 is a schematic cross-sectional view showing a display device including the phosphor substrate according to the third embodiment.
A display device 600 according to this embodiment includes a phosphor substrate 650, an excitation light source 614, and a liquid crystal layer 615. The excitation light source 614 is a light source device that emits excitation light FL having a wavelength of 450 nm, for example. The liquid crystal layer 615 may be a known liquid crystal layer that controls the incidence of the excitation light FL on the phosphor substrate 650.

  The phosphor substrate 650 includes a light-transmitting substrate 601 and a phosphor layer 602 disposed so as to overlap one surface 601a of the substrate 601. The phosphor substrate 650 has an excitation light incident surface Ef on which the excitation light FL for exciting the phosphor layer 602 is incident on the opposite side of the phosphor layer 602 from the surface facing the substrate 601.

  It is preferable that a band pass filter layer 605 is further formed on the excitation light incident surface Ef of the phosphor layer 602. The band-pass filter layer 605 transmits the excitation light FL and reflects light emitted from the phosphor layer 602 by the excitation light FL.

  The phosphor layer 602 includes a large number of phosphor particles 603 made of a phosphor material and voids 604 maintained between the phosphor particles 603. The gap 604 is filled with argon gas. The phosphor layer 602 rises from one surface 601a of the substrate 601 and is partitioned for each predetermined region by a partition wall 612 surrounding the side surface along the thickness direction of the phosphor layer 602. A region of the partition 612 facing at least the phosphor particles 603 has light scattering property or light reflecting property. Further, it is preferable that a light shielding layer 611 is further formed between the bottom of each partition wall 612 and the substrate 601.

  The phosphor particles 603 are filled with red phosphor particles 603R, green phosphor particles 603G, and scatterer particles 603S for each region partitioned by the partition 612. Of the phosphor particles 503, the emission main wavelength of the green phosphor particles 503G (first phosphor particles) is 500 to 560 nm. Further, the scatterer particles 603S scatter light (fluorescence) in a wavelength region of 400 nm or more.

  Further, between the red phosphor particles 603R, the green phosphor particles 603G, the scatterer particles 603S, and the substrate 601, a red filter 613R, a green filter 613G, which is a color filter 613 partitioned by a light shielding layer 611, and a blue color, respectively. A filter 613B is formed. The red filter 613R transmits light having a wavelength region of 600 to 650 nm as a main wavelength. The green filter 613G transmits light having a wavelength region of 500 to 560 nm as a main wavelength. The blue filter 613B transmits light having a wavelength region of 430 to 490 nm as a main wavelength.

  The scatterer particle 603S may be made of an organic material or an inorganic material, but is preferably made of an inorganic material. This makes it possible to diffuse or scatter light having directivity from the outside (for example, a light emitting element) more isotropically and effectively. Further, by using an inorganic material, it is possible to provide a light scattering layer that is stable to light and heat. Moreover, it is preferable that the scatterer particles 603S have high transparency. Further, it is preferable that particles having a higher refractive index than the base material are dispersed in the low refractive index base material. Further, in order for blue light to be effectively scattered by the scatterer particles 603S, the particle size of the scatterer particles 603S needs to be in the Mie scattering region. About 500 nm is preferable.

  When an inorganic material is used as the scatterer particle 603S, for example, an oxide of at least one metal selected from the group consisting of silicon, titanium, zirconium, aluminum, indium, zinc, tin, and antimony is used as a main component. Particles and the like.

  In the case of using the scatterer particles 603S and particles (inorganic particles) made of an inorganic material, for example, silica beads (refractive index: 1.44), alumina beads (refractive index: 1.63), titanium oxide. Beads (refractive index anatase type: 2.50, rutile type: 2.70), zirconia bead (refractive index: 2.05), zinc oxide beads (refractive index: 2.00), barium titanate (BaTiO3) ( Refractive index: 2.4) etc. are mentioned.

  When particles (organic particles) made of an organic material are used as the scatterer particles 603S, for example, polymethyl methacrylate beads (refractive index: 1.49), acrylic beads (refractive index: 1.50), acrylic -Styrene copolymer beads (refractive index: 1.54), melamine beads (refractive index: 1.57), high refractive index melamine beads (refractive index: 1.65), polycarbonate beads (refractive index: 1.57) Styrene beads (refractive index: 1.60), crosslinked polystyrene beads (refractive index: 1.61), polyvinyl chloride beads (refractive index: 1.60), benzoguanamine-melamine formaldehyde beads (refractive index: 1.68) And silicone beads (refractive index: 1.50).

  The resin material used by mixing with the scatterer particles 603S is preferably a translucent resin. Examples of the resin material include acrylic resin (refractive index: 1.49), melamine resin (refractive index: 1.57), nylon (refractive index: 1.53), polystyrene (refractive index: 1.60). , Melamine beads (refractive index: 1.57), polycarbonate (refractive index: 1.57), polyvinyl chloride (refractive index: 1.60), polyvinylidene chloride (refractive index: 1.61), polyvinyl acetate ( Refractive index: 1.46), polyethylene (refractive index: 1.53), polymethyl methacrylate (refractive index: 1.49), poly MBS (refractive index: 1.54), medium density polyethylene (refractive index: 1) .53), high density polyethylene (refractive index: 1.54), tetrafluoroethylene (refractive index: 1.35), poly (trifluoroethylene chloride) (refractive index: 1.42), polytetrafluoroethylene (refractive index) : .35), and the like.

  Note that as the excitation light source 614 for exciting the phosphor layer 602 of the phosphor substrate 650, an illumination device using an organic EL element can also be used as the excitation light source. As the organic EL element, a known organic EL element can be applied.

[Fourth Embodiment]
FIG. 9 is a schematic cross-sectional view showing a light emitting device including the phosphor substrate according to the fourth embodiment.
The light emitting device 700 of this embodiment includes a phosphor substrate 710 and a light source 711. The phosphor substrate 710 includes a substrate 701 and a phosphor layer 702 formed on one surface 701a of the substrate 701. The phosphor layer 702 is composed of a large number of phosphor particles 703 made of a phosphor material, and voids 704 held between the phosphor particles 703. The air gap 704 is filled with air. Further, the phosphor particles 703 may be any mixture of red phosphor particles 703R that emit red light by excitation light emitted from the light source 711 and green phosphor particles 703G that emit green light, for example. Further, it is preferable that a band pass filter layer 705 is further formed on the phosphor layer 702 on the light source 711 side.

  The light source 711 includes a base material 713 provided with an LED chip 712, a transparent sealing resin 714 that seals the LED chip 712 to the base material 713, and a reflector formed so as to surround the LED chip 712 and the sealing resin 714. 715, a lead wire 716 of the LED chip 712 formed along the peripheral surface of the base 713, a wire 717 for connecting the LED chip 712 and the lead wire 716, and the like.

  The wire 717 may be a conductive metal alloy, but gold, gold alloy, aluminum, copper, silver, or the like is mainly used from the viewpoint of easy alloying with the LED chip 712 or the electrode material. In addition, although what was wire-bonded is shown in FIG. 8, what mounted the flip chip mounting of LED chip 712 may be sufficient. Further, for the purpose of improving electrostatic characteristics, an electrostatic protection element (for example, a Zener diode or a resistance element) may be connected in parallel with the LED chip 712.

The LED chip 712 may be an LED chip containing GaN that emits blue light (excitation light), for example. The reflector 715 uses nylon-based polyphthalamide (PPA) or a silicone-based resin as a molding resin, and a filler for expressing light scattering in the molding resin, such as TiO ₂ , SiO ₂ , alumina, Consists of dispersed aluminum nitride, mullite, etc.

The sealing resin 714 may be made of epoxy resin, urea resin, silicone resin, modified epoxy resin, modified silicone resin, polyamide, glass, or the like.
As the phosphor particles, in addition to mixing the red phosphor particles 703R and the green phosphor particles 703G, for example, it is also preferable to use yellow phosphor particles that emit yellow light.

  Like the light emitting device 700 of this embodiment, the phosphor substrate 710 is used for the LED chip 712, thereby improving the light emission luminance and suppressing the variation in manufacturing quality due to the combination of the LED chip 712 and the phosphor substrate 710. The effect of suppressing the deterioration of the phosphor particles 703 by separating the LED chip 712 that emits heat and the phosphor particles 703 can be obtained.

[Modification of Fourth Embodiment]
FIG. 10 is a schematic cross-sectional view showing a light emitting device including the phosphor substrate according to the fourth embodiment.
In the light emitting device 700 shown in FIG. 9, the light source 711 having a configuration in which one LED chip 712 is arranged on one surface of the base material 713 is used. However, in the modification of the fourth embodiment shown in FIG. A plurality of LED chips 712, 712,... These LED chips 712, 712,... Can be used as surface light sources that are connected in series to illuminate a wide range. The LED chip 712 may be connected in series or in parallel.

[Fifth Embodiment]
FIG. 11: is a cross-sectional schematic diagram which shows the solar cell module provided with the fluorescent substance substrate of 5th Embodiment.
In the solar cell module 800 of this embodiment, a phosphor substrate 810 and a photoelectric conversion element 817 are formed so as to overlap each other.
The phosphor substrate 810 includes a light-transmitting substrate 801 and a phosphor layer 802 arranged so as to overlap one surface 801a of the substrate 801. The phosphor layer 802 includes a large number of phosphor particles 803 made of a phosphor material and voids 804 held between the phosphor particles 803. The air gap 804 is filled with air.

Examples of the photoelectric conversion element 817 include a silicon solar cell, a GaAs solar cell, a CuInGaSe mixed crystal solar cell (ClGS solar cell), and the like. The photoelectric conversion element 817, in addition to those described above, for _{example, InGaP, InGaAs, AlGaAs, Cu} (In, Ga) Se 2, Cu (In, Ga) (Se, S) 2, CuInS 2, CdTe, CdS Etc. can also be used. Furthermore, it is also preferable to use a solar cell having another structure such as a quantum dot solar cell as the photoelectric conversion element.

  As shown in FIG. 12, in any of the crystalline silicon solar cell, the GaAs solar cell, and the ClGS solar cell, the optical power conversion efficiency φ is the maximum at the wavelength determined by the band gap of the material of each solar cell element. Then, the longer wavelength side is steeply lowered, and the conversion efficiency is slowly lowered on the shorter wavelength side.

  On the other hand, as shown in FIG. 13, the spectrum of sunlight (air mass 1.5) rises steeply from a wavelength of about 300 nm, reaches a maximum at a wavelength of about 460 nm, and the intensity gradually decreases on the longer wavelength side.

Therefore, if the light on the short wavelength side of sunlight is converted by the phosphor substrate 810 into light having a higher photovoltaic power conversion efficiency φ of the solar cell element, the photoelectric conversion efficiency of the entire solar cell module can be improved. It becomes possible.
On the other hand, when the wavelength of the light converted by the phosphor substrate 810 is longer than the maximum value of the photoelectric conversion efficiency φ of the solar cell element, the photoelectric conversion efficiency of the entire solar cell module is lowered.

FIG. 13 is a graph showing the effect of combining the phosphor substrate 810 with the photoelectric conversion element 817. “Components absorbed by phosphor particles 803 in the spectrum of sunlight (see FIG. 18)” when red phosphor CaAlSiN ₃ : Eu ²⁺ is used as phosphor particles 803 constituting phosphor substrate 810 (refer to FIG. 18 below). (Referred to as spectrum I), “emission spectrum of phosphor substrate 810 (see FIG. 18)” (hereinafter referred to as spectrum II), “sunlight spectrum (air mass 1.5)” (hereinafter referred to as spectrum III), “Spectrum of sunlight passing through phosphor particles 803” (hereinafter referred to as spectrum IV), “Optical power conversion efficiency φ spectrum of crystalline silicon solar cell (see FIG. 18)” (hereinafter referred to as spectrum V), Shown again. According to FIG. 14, sunlight with a peak on the short wavelength side is emitted by the phosphor substrate 810 with respect to the crystalline silicon solar cell having the characteristic that the photoelectric conversion efficiency increases uniformly toward the long wavelength side. This indicates that the light can be converted to the longer wavelength side, whereby the photoelectric conversion efficiency of the photoelectric conversion element 817 by sunlight can be improved.

  More specifically, when the phosphor substrate 810 is irradiated with sunlight from the wavelength selection film side, the phosphor substrate 810 absorbs the spectrum I, converts the wavelength into the spectrum II, and the light is incident on the photoelectric conversion element 817 side. It is taken out. In addition, the spectrum IV transmitted through the phosphor substrate 810 is also irradiated to the electric conversion element 817.

  When the numerical values are read from FIG. 13, the optical power conversion efficiency φ of the photoelectric conversion element 817 having a wavelength region of spectrum I, more specifically, about 300 nm to about 600 nm, is 7% to 19%. The optical power conversion efficiency φ of the photoelectric conversion element 817 in the wavelength region of the spectrum II, more specifically, about 600 nm to about 750 nm is 19% to 25%. Comparing the both, it can be seen that the photoelectric power conversion efficiency φ of the photoelectric conversion element 817 is higher in the wavelength region of the spectrum II.

Here further,
(Left side) [Spectrum I × Photoelectric power conversion efficiency of solar cell φ (Spectrum V)]
Λ
(Right side) [Spectrum II × Quantum efficiency of phosphor × Extraction efficiency × Photoelectric power conversion efficiency of solar cell φ (Spectrum V)]
In this case, the photoelectric conversion efficiency of the entire solar cell module can be improved. The above (left side) does not apply the phosphor substrate 810, and the amount of power generated when sunlight directly enters the photoelectric conversion element 817. It is. The spectrum I and the spectrum V in FIG. 13 are proportional to the overlapping area.

  On the other hand, the above (right side) is the amount of power generated when sunlight is incident on the solar cell module 800 of this embodiment in which the phosphor substrate 810 is directly applied to the photoelectric conversion element 817. When the phosphor substrate 810 absorbs the spectrum I and emits the spectrum II to the photoelectric conversion element 817, the light intensity is reduced by multiplying the quantum efficiency of the phosphor particles 803 and the extraction efficiency of the phosphor substrate 810. Therefore, the amount obtained by multiplying the spectrum obtained by multiplying the spectrum II by the quantum efficiency and the extraction efficiency of the phosphor by the spectrum V is the power generation amount of the solar cell module 800 of the present embodiment. The power generation amount of the solar cell module 800 of this embodiment is proportional to the amount obtained by multiplying the area where the spectrum II and the spectrum V of FIG. 134 overlap with the quantum efficiency and the extraction efficiency of the phosphor.

Therefore, in order to improve the power generation amount of the entire solar cell module, the light extraction efficiency of the phosphor substrate 810 needs to be sufficiently high. By applying the phosphor substrate 810 having the configuration of the present invention, which can be expected to have high extraction efficiency, to the photoelectric conversion element 817, it becomes easy to satisfy the above formula (left side) (right side).
Further, the phosphor substrate 810 converts the wavelength into a wavelength region where the optical power conversion efficiency φ is high and makes light incident on the photoelectric conversion element 817, so that the temperature rise of the photoelectric conversion element 817 can be suppressed, and the light of the photoelectric conversion element 817 can be suppressed. Degradation of power conversion characteristics can be prevented.
Above (left side)

In FIG. 14, the absorption spectrum (absorption rate) and emission spectrum (light intensity) of the red phosphor (CaAlSiN ₃ : Eu ²⁺ ) constituting the phosphor substrate 810 and the spectrum of sunlight (air mass 1.5), The component which a red fluorescent substance absorbs in the spectrum of sunlight is shown.

FIG. 15 shows the emission spectrum (light intensity) of the red phosphor (CaAlSiN ₃ : Eu ²⁺ ) that also constitutes the phosphor substrate 810 and the optical power conversion efficiency φ of the crystalline silicon solar cell.
According to the red phosphor having such characteristics, the spectrum of sunlight can be converted to the long wavelength side, and the photoelectric conversion efficiency of the photoelectric conversion element 817 can be improved.

  As another configuration, FIG. 16 shows the absorption spectrum (absorption rate), emission spectrum (light intensity) and spectrum of sunlight (air mass 1.5) of the red phosphor (perylene dye lumogen red) constituting the phosphor substrate 810. ), A component absorbed by the red phosphor in the sunlight spectrum.

FIG. 17 shows the components absorbed by the red phosphor in the emission spectrum (light intensity) and sunlight spectrum of the red phosphor (perylene dye lumogen red) that also constitutes the phosphor substrate 810, and the crystalline silicon solar cell. The optical power conversion efficiency φ is shown.
Even in a red phosphor having such characteristics, the spectrum of sunlight can be converted to the longer wavelength side, and the photoelectric conversion efficiency of the photoelectric conversion element 817 can be improved.

  The phosphor substrate and the light emitting device according to the above embodiment can be applied to a mobile phone 1000 as an electronic apparatus, for example, as shown in FIG. A cellular phone 1000 illustrated in FIG. 19A includes a voice input portion 1003, a voice output portion 1004, an antenna 1005, an operation switch 1006, a display portion 1002, a housing 1001, and the like. The phosphor substrate and the light emitting device of the above embodiment can be suitably applied as the display unit 1002. By applying the phosphor substrate and the light emitting device according to the above embodiment to the display portion 1002 of the mobile phone 1000, a high contrast image can be displayed with low power consumption.

    The phosphor substrate and the light emitting device according to the above embodiment can be applied to a thin television 1100 as an electronic apparatus, for example, as shown in FIG. A thin television 1100 illustrated in FIG. 19B includes a display portion 1102, a speaker 1103, a cabinet 1101, a stand 1104, and the like. The phosphor substrate and the light emitting device of the above embodiment can be suitably applied as the display unit 1102. By applying the phosphor substrate and the light-emitting device according to the above embodiment to the display portion 1102 of the thin television 1100, a high-contrast image can be displayed with low power consumption.

    The phosphor substrate and the light emitting device according to the above embodiment can be applied to a ceiling light 1400 as a lighting device, for example, as shown in FIG. A ceiling light 1400 illustrated in FIG. 20A includes a light emitting portion 1401, a suspended line 1402, a power cord 1403, and the like. The phosphor substrate and light emitting device of the above embodiment can be suitably applied as the light emitting unit 1401. By applying the phosphor substrate and the light-emitting device according to the above embodiment to the light-emitting portion 1401 of the ceiling light 1400, it is possible to obtain illumination light of a free color tone with low power consumption, and realize a lighting device with high light performance. can do. In addition, it is possible to realize a lighting fixture capable of emitting surface light with high color purity with uniform illuminance.

    The phosphor substrate and the light emitting device according to the above embodiment can be applied to a lighting stand 1500 as a lighting device, for example, as shown in FIG. A lighting stand 1500 illustrated in FIG. 20B includes a light-emitting portion 1501, a stand 1502, a main switch 1503, a power cord 1504, and the like. The phosphor substrate and light emitting device of the above embodiment can be suitably applied as the light emitting unit 1501. By applying the phosphor substrate and the light-emitting device according to the above embodiment to the light-emitting portion 1501 of the lighting stand 1500, it is possible to obtain illumination light of a free color tone with low power consumption, and realize a lighting device with high light performance. can do. In addition, it is possible to realize a lighting fixture capable of emitting surface light with high color purity with uniform illuminance.

  100 phosphor substrate, 101 substrate, 102 phosphor layer, 103 phosphor particle, 104 void, 106 adhesive layer (member), 105 band pass filter layer.

Claims (32)

A light transmissive substrate, a phosphor layer formed on one surface of the substrate, a wavelength selective film formed on the phosphor layer,
A phosphor substrate comprising at least
The phosphor layer emits light by excitation light,
The phosphor layer is composed of a large number of phosphor particles and voids kept between the phosphor particles.   The phosphor substrate according to claim 1, wherein the excitation light has a wavelength range of 400 nm or more and 1500 nm or less.   3. The phosphor substrate according to claim 1, wherein an average dimension of the voids is equal to or greater than a dominant wavelength of light emitted from the phosphor layer.   4. The phosphor substrate according to claim 1, wherein the gap is filled with a low refractive medium.   5. The phosphor substrate according to claim 4, wherein the low refractive medium is a gas.   6. The phosphor substrate according to claim 5, wherein the gas is air, nitrogen, argon, or a mixed gas thereof.   The phosphor substrate according to claim 1, wherein a member made of a material different from that of the phosphor particles is disposed in the gap.   A partition that rises from one surface of the substrate and surrounds a side surface in the thickness direction of the phosphor layer is further formed, and at least a region of the partition facing the phosphor layer has light scattering or light reflectivity. The phosphor substrate according to any one of claims 1 to 7, characterized in that:   The phosphor substrate according to claim 8, wherein the partition wall partitions the phosphor layer into a plurality of regions.   The phosphor particles are composed of a plurality of types of phosphor particles made of mutually different phosphor materials, and the emission main wavelength of the first phosphor particles is 500 to 560 nm among the plurality of types of phosphor particles. The phosphor substrate according to claim 1, wherein:   11. The phosphor substrate according to claim 10, wherein only the first phosphor particles are accommodated in the first compartment among the compartments of the plurality of regions.   The phosphor substrate according to claim 10 or 11, wherein the first phosphor particles are composed of a plurality of types of phosphor particles having different emission main wavelengths within a range of 500 to 560 nm.   Between the said board | substrate and the said fluorescent substance layer in said 1st division, it has the maximum value of the transmittance | permeability in the wavelength range of 500-560 nm, and also the transmittance | permeability of the light of the wavelength range of 500-560 nm is 430- The phosphor substrate according to claim 11, further comprising a filter layer having a larger transmittance than the maximum transmittance of light in each wavelength region of 490 nm and 600 to 650 nm.   The phosphor particles are composed of a plurality of types of phosphor particles made of different phosphor materials, and among the plurality of types of phosphor particles, the emission main wavelength of the second phosphor particles is 600 to 650 nm. The phosphor substrate according to claim 1, wherein:   The phosphor substrate according to claim 14, wherein only the second phosphor particles are accommodated in a second compartment among the plurality of regions.   Between the said board | substrate and the said fluorescent substance layer in said 2nd division, it has the maximum value of the transmittance | permeability in the wavelength range of 600-650 nm, and also the transmittance | permeability of the light of the wavelength range of 600-650 nm is 430-300. The phosphor substrate according to claim 15, further comprising a filter layer having a larger transmittance than that of light in each wavelength region of 490 nm and 500 to 560 nm.   The phosphor particles are composed of a plurality of types of phosphor particles made of different phosphor materials, and among the plurality of types of phosphor particles, the emission main wavelength of the third phosphor particles is 430 to 490 nm. The phosphor substrate according to claim 1, wherein:   18. The phosphor substrate according to claim 17, wherein only the third phosphor particles are accommodated in a third section among the sections of the plurality of regions.   Between the said board | substrate and the said fluorescent substance layer in said 3rd division, it has the maximum value of the transmittance | permeability in the wavelength range of 430-490 nm, and also the transmittance | permeability of the light of the wavelength range of 430-490 nm is 500- The phosphor substrate according to claim 18, further comprising a filter layer having a larger transmittance than the maximum transmittance of light in each wavelength region of 560 nm and 600 to 650 nm.   The phosphor particles are composed of a plurality of types of phosphor particles made of different phosphor materials, and among the plurality of types of phosphor particles, the emission main wavelength of the fourth phosphor particles is 560 to 590 nm. The phosphor substrate according to claim 1, wherein:   21. The phosphor substrate according to claim 20, wherein only the fourth phosphor particles are accommodated in a fourth compartment among the plurality of regions.   The phosphor layer is formed between the substrate and the wavelength selection film, and the wavelength selection film transmits the excitation light and reflects the light emission. The phosphor substrate according to 1. A light transmissive substrate, a phosphor layer formed on one surface of the substrate, a wavelength selective film formed on the phosphor layer,
A phosphor substrate comprising at least
The phosphor layer emits light by excitation light,
The wavelength selective film transmits the excitation light and reflects the emission;
A phosphor substrate having a light emission extraction efficiency of 55% or more by which light emitted from the phosphor layer is transmitted through and extracted from the substrate.
The phosphor layer is composed of a large number of phosphor particles and voids kept between the phosphor particles.   The phosphor substrate according to claim 23, wherein the excitation light has a wavelength range of 400 nm or more and 1500 nm or less.   25. A light emitting device comprising: the phosphor substrate according to claim 1; and a light source that emits the excitation light.   26. The light emitting device according to claim 25, wherein the light source is an LED element.   26. The light emitting device according to claim 25, wherein the light source is an organic EL element.   28. The light-emitting device according to claim 25, further comprising a liquid crystal layer for controlling the incidence of the excitation light between the phosphor substrate and the light source.   A display device comprising the light-emitting device according to claim 25.   An illumination apparatus comprising the light emitting device according to any one of claims 25 to 28.   A solar cell module comprising the phosphor substrate according to any one of claims 1 to 24 and a photoelectric conversion element. 32. The sun according to claim 31, wherein in the solar cell module, the peak wavelength of the emission spectrum of the phosphor layer is shorter than the wavelength of light that maximizes the photoelectric conversion efficiency of the photoelectric conversion element. Battery module.