KR102693771B1 - Phosphor plate and method of manufacturing thereof - Google Patents

Abstract

The embodiment discloses a phosphor plate including: a substrate; a plurality of phosphor layers including a first phosphor layer disposed on the substrate and a second phosphor layer disposed on the first phosphor layer; a first boundary layer disposed between the first phosphor layer and the second phosphor layer and including pores;

Description

Phosphor plate and method of manufacturing same {PHOSPHOR PLATE AND METHOD OF MANUFACTURING THEREOF}

The present invention relates to a phosphor plate and a method for manufacturing the same.

The phosphor plate contains phosphor powder and can convert the color of light output from a light source such as an LED (Light Emitting Diode) or LD (Laser Diode).

However, the light emitted from the light source has high power at the center, so when it passes through the phosphor plate, a yellow circle can appear at the edge, which is called the 'yellow ring' phenomenon.

Phosphor plates may have limitations in widely dispersing the light emitted from a light source.

In addition, there may be a problem of carbonization when combining a fluorescent plate with a transparent member using an adhesive, binder, etc. in general.

In addition, there may be issues with reliability.

The embodiments provide a phosphor plate and a method for manufacturing the same, and an optical device including the phosphor plate.

In addition, a phosphor plate having excellent light diffusion efficiency is provided.

Additionally, a phosphor plate with improved reliability is provided.

Additionally, it provides a phosphor plate with large light scattering inside.

According to one embodiment of the present invention, a phosphor plate includes: a substrate; a plurality of phosphor layers including a first phosphor layer disposed on the substrate and a second phosphor layer disposed on the first phosphor layer; and a first boundary layer disposed between the first phosphor layer and the second phosphor layer and including pores.

The refractive index of the plurality of fluorescent layers may be different from the refractive index of the first boundary layer.

The refractive index of the first boundary layer may be 0.5 to 0.6 times the refractive index of the plurality of fluorescent layers.

The above first boundary layer may have pores formed.

The above plurality of phosphor layers may include at least one of YAG, LuAg, and LuYAG.

The above plurality of phosphor layers may include a diffuser.

The above-mentioned dispersants are Al ₂ O ₃ , TiO ₂ , ZrO ₂ and may include at least one of Y ₂ O ₃ , SiO ₂ .

The thickness of each of the plurality of fluorescent layers may be 50 ㎛ to 150 ㎛.

The surface roughness of the above plurality of fluorescent layers may be 0.23 ㎛ to 0.27 ㎛.

The above plurality of phosphor layers may further include a third phosphor layer disposed on the second phosphor layer, and may further include a second boundary layer disposed between the second phosphor layer and the third phosphor layer and including pores.

An optical device according to one embodiment of the present invention includes a phosphor plate including a light source; a substrate on which light emitted from the light source is irradiated; a plurality of phosphor layers including a first phosphor layer disposed on the substrate and a second phosphor layer disposed on the first phosphor layer; and a first boundary layer disposed between the first phosphor layer and the second phosphor layer and including pores.

The refractive index of the first boundary layer may be 0.5 to 0.6 times the refractive index of the plurality of fluorescent layers.

The above first boundary layer may have pores formed.

The light source may be at least one of a laser and a light emitting diode (LED).

The above plurality of phosphor layers may further include a third phosphor layer disposed on the second phosphor layer, and may further include a second boundary layer disposed between the second phosphor layer and the third phosphor layer and including pores.

A method for manufacturing a phosphor plate according to one embodiment of the present invention includes the steps of spraying a phosphor onto a substrate; and the steps of spraying the phosphor multiple times to form a plurality of phosphor layers; wherein a boundary layer including pores is arranged between the plurality of phosphor layers.

The above-mentioned phosphor can be sprayed onto the substrate by at least one of cold spray coating, thermal spray coating, and plasma coating.

According to an embodiment, a phosphor plate having a large surface roughness can be implemented.

In addition, a fluorescent plate with excellent light diffusion efficiency can be manufactured.

In addition, it is possible to manufacture a phosphor plate with improved reliability.

In addition, by allowing the light to spread widely, the light efficiency can be increased while also preventing the occurrence of the 'yellow ring' phenomenon.

Additionally, it is possible to manufacture a phosphor plate with large internal light scattering.

The various advantageous and beneficial effects of the present invention are not limited to the above-described contents, and will be more easily understood in the course of explaining specific embodiments of the present invention.

Figure 1 is a drawing showing the yellow ring phenomenon that occurs in a conventional fluorescent plate.
Figure 2 is a cross-sectional view of a fluorescent plate according to the first embodiment of the present invention.
Figure 3 is an enlarged cross-sectional view of another fluorescent plate according to the first embodiment.
Figure 4 is a drawing explaining the light diffusion in the boundary layer in part A of Figure 3.
FIG. 5 is a drawing illustrating the surface of a fluorescent plate according to the first embodiment.
Figure 6 is a drawing showing the surface roughness of a conventional fluorescent plate.
Fig. 7 is a drawing showing the surface roughness of a fluorescent plate according to the first embodiment.
Fig. 8 is a cross-sectional view of a fluorescent plate according to the second embodiment of the present invention.
Fig. 9 is a drawing showing the orientation angle of the fluorescent plate according to the first embodiment.
Fig. 10 is a drawing showing the orientation angle of a fluorescent plate according to the second embodiment.
Figure 11 is a flow chart of a method for manufacturing a fluorescent plate according to the first embodiment.
Figure 12 is a schematic diagram showing an outline of a cold spray coating device.
Figure 13 is a schematic diagram showing an outline of a thermal spray coating device.
FIG. 14 and FIG. 15 are drawings showing examples of applying the fluorescent plate according to the first embodiment to various optical devices.

The present invention can have various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, but should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

Terms including ordinal numbers such as second, first, etc. may be used to describe various components, but the components are not limited by the terms. The terms are only used to distinguish one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as the first component, and similarly, the first component may also be referred to as the second component. The term and/or includes any combination of a plurality of related described items or any item among a plurality of related described items.

When it is said that a component is "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components in between. On the other hand, when it is said that a component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprises" or "has" and the like are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms defined in commonly used dictionaries, such as those defined in common dictionaries, should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and shall not be interpreted in an idealized or overly formal sense, unless expressly defined in this application.

Hereinafter, embodiments will be described in detail with reference to the attached drawings. Regardless of the drawing symbols, identical or corresponding components are given the same reference numerals and redundant descriptions thereof will be omitted.

Fig. 1 is a drawing showing a yellow ring phenomenon that occurs in a conventional fluorescent plate. Referring to Fig. 1, in a conventional case, a so-called 'yellow ring' phenomenon (Y) may appear, in which a yellow circle is visible at the edge of light passing through a fluorescent plate (100A). This 'yellow ring' phenomenon (Y) may occur when light passing through a fluorescent plate (100A) is not sufficiently diffused.

FIG. 2 is a cross-sectional view of a fluorescent plate (100A) according to the first embodiment of the present invention.

Referring to FIG. 2, a fluorescent plate (100A) according to the first embodiment may include a substrate (110), a plurality of fluorescent layers (120) disposed on the substrate (110), and a boundary layer (130) disposed between the plurality of fluorescent layers (120).

The substrate (110) may be a flexible substrate. For example, in order to implement a flexible display device, the substrate (110) may include glass or polyimide (PI).

For example, the substrate (110) may include, for example, soda lime silica, boron silicate, alumina silicate, or alkali germano silicate.

Additionally, the substrate (110) may be made of any insulating and flexible material, such as PEN (Polyethylene Naphthalate) or PET (Polyethylene Terephthalate).

Additionally, the substrate (110) may be made of either a transparent material or an opaque material. The thickness (d1) of the substrate (110) may be 400 μm to 500 μm.

A plurality of phosphor layers (120) may be arranged on a substrate (110). The plurality of phosphor layers (120) may include a phosphor. The phosphor layer (120) may be in the form of a hardened phosphor powder, but is not limited thereto.

The phosphor may include at least one of a curable resin and a fluorescent resin composition. The phosphor may perform a wavelength conversion function. For example, the phosphor may be a yellow phosphor capable of converting blue light into yellow light, a red phosphor capable of converting blue light into red light, or the like.

The phosphor may include a garnet-type phosphor having a garnet-type crystal structure, such as a garnet system including yttrium-aluminum-garnet (Y ₃ Al ₅ O ₁₂ : Ce(YAG: Ce), terbium-aluminum-garnet (Tb ₃ Al ₃ O ₁₂ : Ce(TAG: Ce)), and ruthenium-aluminum-garnet (LuAG) systems.

Additionally, the phosphor may include a sulfide-based or silicate-based phosphor.

The fluorescent material may have an average particle diameter of 0.1 ㎛ to 0.5 ㎛, but is not limited thereto.

There may be multiple fluorescent layers (120). For example, the fluorescent layer (120) may include a first fluorescent layer (120a), a second fluorescent layer (120b), a third fluorescent layer (120c), and a fourth fluorescent layer (120d), but is not limited thereto.

The thickness (d2) of each phosphor layer (120a, 120b, 120c, 120d) may be 50 µm to 150 µm. And the thickness of the entire phosphor layer (120) may be 200 µm to 600 µm. Here, the thickness may be the length in the Y-axis direction.

In addition, the thickness (d2) of each fluorescent layer (120a, 120b, 120c, 120d) may be the same. However, this is not limited to the present invention, and each fluorescent layer (120a, 120b, 120c, 120d) may be formed differently.

The boundary layer (130) may be arranged between a plurality of fluorescent layers (120). There may also be a plurality of boundary layers (130). For example, the boundary layer (130) may include a first boundary layer (130a), a second boundary layer (130b), and a third boundary layer (130c), but is not limited thereto.

Additionally, a first boundary layer (130a) may be arranged between the first phosphor layer (120a) and the second phosphor layer (120b). The boundary layer (130) may include pores. The pores may be created by repeatedly coating the phosphor layers without firing and bonding during the process of manufacturing the phosphor plate (100A).

FIG. 3 is an enlarged cross-sectional view of a fluorescent plate according to another embodiment of the present invention, and FIG. 4 is a drawing explaining light diffusion in a boundary layer in part A of FIG. 3.

Referring to FIGS. 3 and 4, there are multiple fluorescent layers (120), and a boundary layer (130) can be placed between adjacent fluorescent layers (120).

The boundary layer (130) can be placed between adjacent phosphor layers (120) by applying a repeated phosphor coating method to the substrate (110). The phosphor coating method may use at least one of cold spray coating, thermal spray coating, and plasma coating, but is not limited thereto.

By performing repeated coating operations, the boundary layer (130) can be formed into an irregular rough structure. By this configuration, light diffusion can be improved. However, the present invention is not limited thereto.

A first boundary layer (130a) may be placed between the first fluorescent layer (120a) and the second fluorescent layer (120b). And the first boundary layer (130a) may include a plurality of pores.

For example, the excited light emitted from the light source can pass through the first fluorescent layer (120a) and diffuse into the first boundary layer (130a).

At this time, the above-mentioned light can be amplified in scattering due to the pores of the first boundary layer (130a). Accordingly, the fluorescent plate (100A) according to the first embodiment can greatly improve light diffusion. In addition, the yellow ring phenomenon can be additionally prevented.

FIG. 5 is a drawing illustrating a surface of a fluorescent plate according to the first embodiment. Referring to FIG. 5, the surface of the upper portion of a plurality of fluorescent layers (120) may be rough.

When manufacturing a phosphor plate (100A), the phosphor layer (120) is formed by at least one of cold spray coating, thermal spray coating, and plasma coating, so the surface roughness may be greater than when the phosphor layer (120) is formed by sintering or the like.

The surface of the fluorescent plate (100A) may have a wavy shape or an uneven shape, but is not limited thereto.

By this configuration, the fluorescent plate (100A) can greatly scatter the light passing through it.

FIG. 6 is a drawing illustrating the surface roughness of a conventional fluorescent plate, and FIG. 7 is a drawing illustrating the surface roughness of a fluorescent plate according to the first embodiment.

Referring to Fig. 6, when a phosphor layer (120) is formed by sintering, the surface roughness of the phosphor layer may be 0.03 µm to 0.4 µm. Additionally, the average surface roughness of the phosphor layer formed by sintering may be 0.035 µm.

Referring to FIG. 7, the surface roughness of the fluorescent plate (100A) according to the first embodiment of the present invention may be 0.23 ㎛ to 0.27 ㎛. In addition, the average surface roughness of the fluorescent plate (100A) according to the first embodiment may be 0.25 ㎛. However, it is not limited thereto, and may be applied in various ways depending on the size of the sintered body, etc.

According to this configuration, the surface of the fluorescent layer (120) formed by sintering is flat, so that less scattering can occur when light passes through it. Accordingly, the light can have a strong tendency to travel in a straight line.

On the other hand, since the fluorescent plate (100A) according to the first embodiment has a large surface roughness, light can be scattered in various directions on the surface of the fluorescent plate (100A). Accordingly, the fluorescent plate (100A) of the first embodiment can greatly diffuse light.

The refractive index of the plurality of fluorescent layers (120) may be different from the refractive index of the boundary layer (130). The refractive index of the boundary layer (130) may be 0.5 to 0.6 times the refractive index of the fluorescent layer (120).

For example, the refractive index of the fluorescent layer (120) may be 1.8, and the refractive index of the boundary layer (130) including pores may be 1.0. With this configuration, light may be significantly scattered due to the difference in refractive index between the fluorescent layer (120) and the boundary layer (130).

Light passing through the first fluorescent layer (120a) can be scattered in various directions in the first boundary layer (130a) which has a different refractive index than that of the first fluorescent layer (120a).

In addition, light scattered in the first boundary layer (130a) can be scattered again in the second phosphor layer (120b) having a different refractive index than that of the first boundary layer (130a). Accordingly, light can be scattered repeatedly according to the number of boundary layers (130) in the phosphor plate (100A) of the embodiment. Accordingly, the phosphor plate (100A) of the embodiment can improve the light diffusion efficiency.

Figure 8 is a cross-sectional view of a fluorescent plate according to the second embodiment of the present invention.

A phosphor plate (100B) according to the second embodiment may include a substrate (110), a plurality of phosphor layers (120) disposed on the substrate (110) and including a phosphor and a diffuser, and a boundary layer (130) disposed between the plurality of phosphor layers (120).

The contents of the substrate (110), the fluorescent substance, and the boundary layer (130) can be applied identically to the contents described in the fluorescent substance plate (100A) according to the first embodiment.

The phosphor layer (120) of the phosphor plate (100B) according to the second embodiment may include a phosphor and a diffuser.

Diffusers can improve the light distribution. And the diffusers are Al ₂ O ₃ , TiO ₂ , ZrO ₂ and may include at least one of Y ₂ O ₃ , SiO ₂ .

In addition, the diffuser is a light diffuser, and may include an organic light diffuser or an inorganic light diffuser. The organic light diffuser may include, but is not necessarily limited to, acrylic particles, siloxane particles, urethane particles, melamine particles, polycarbonate particles, styrene particles, etc.

The above inorganic light diffusing agent may include, but is not necessarily limited to, calcium carbonate, barium sulfate, titanium dioxide, aluminum hydroxide, silica, glass, talc, mica, white carbon, magnesium oxide, zinc oxide, etc.

A light diffusing agent can secure excellent light diffusion effects while improving scratch resistance.

The amount of the diffuser may be 10 wt% to 30 wt% by weight relative to the fluorescent substance. If the amount of the diffuser is less than 10 wt% by weight relative to the fluorescent substance, it is difficult to secure a sufficient reflection effect, and if the amount of the diffuser is more than 30 wt% by weight, it is difficult to secure sufficient dispersibility.

The average particle size of the dispersant may be 0.1 ㎛ to 0.5 ㎛, but is not limited thereto.

In addition, the diffuser can form a layer within the fluorescent layer (120). At this time, the layer including the diffuser can have a thickness of 5 μm to 10 μm. And the layer including the fluorescent substance can have a thickness of 80 μm to 90 μm. However, the present invention is not limited thereto.

In addition to uniformly distributing the brightness of light, a diffuser can also change the path of some light.

Thereby, the diffuser can increase the amount of light passing through the fluorescent plate (100A). In addition, the diffuser can further improve the diffusion of light passing through the fluorescent plate (100A).

FIG. 9 is a drawing showing the orientation angle of a phosphor plate according to the first embodiment, and FIG. 10 is a drawing showing the orientation angle of a phosphor plate according to the second embodiment.

Referring to FIGS. 9 and 10, the beam angle of the phosphor plate according to the first embodiment may be 122°. And the beam angle of the phosphor plate according to the second embodiment may be 143°. Here, the beam angle is defined as the beam angle of light passing through the phosphor plate.

The area where light passes through the phosphor plate according to the second embodiment is emitted may be larger than the area where light passes through the phosphor plate according to the first embodiment. (Each area (S1, S2) illustrated in FIGS. 9 and 10 is an area where light passes through the phosphor plate is emitted.)

A diffuser can improve the beam spread by enhancing the light diffusion through the phosphor plate, thereby improving the beam angle.

Fig. 11 is a flowchart of a method for manufacturing a phosphor plate according to the first embodiment. Referring to Fig. 11, a method for manufacturing a phosphor plate according to the first embodiment may include a step of spraying a phosphor (S210) and a step of forming a plurality of phosphor layers (S220).

As a method for spraying the phosphor, at least one of cold spray coating, thermal spray coating, and plasma coating can be used.

Referring to FIG. 12, which is a schematic diagram showing an outline of a low-temperature spray coating device, a low-temperature spray coating device (300) may include a gas heater (301) that heats compressed gas, a powder supply device (302) that receives powder of at least one of a fluorescent substance and a dispersant and supplies it to a spray gun (303), a gas nozzle (304) that sprays the heated compressed gas and the supplied material powder onto a substrate (110), and valves (305, 306) that control the supply amount of compressed gas to the gas heater (301) and the powder supply device (302), respectively.

As the compressed gas, helium, nitrogen, air, etc. can be used, but are not limited thereto. The compressed gas supplied to the gas heater (301) can be supplied to the spray gun (303) after being heated to a temperature lower than the melting point of the powder of either the fluorescent substance or the diffusion agent, for example.

The compressed gas supplied to the powder supply device (302) can be supplied so that the material powder in the powder supply device (302) is discharged to the spray gun (303) at a predetermined amount.

The gas pressure of the compressed gas may be, but is not limited to, 1 MPa to 5 MPa.

Powder of either a fluorescent substance or a diffusion agent supplied to the spray gun (303) can be accelerated by compressed gas and collide at high speed on the substrate (110) to form a film. A fluorescent substance layer can be formed with this film.

Any device capable of forming a phosphor layer by colliding powder of either a phosphor or a diffuser in a solid state toward a substrate (110) is not limited to the low-temperature spray coating device (300) shown in FIG. 12.

Fig. 13 is a schematic diagram showing an outline of a thermal spray coating device. Referring to Fig. 13, a thermal spray coating device (400) may include a chamber (401) and a nozzle (402).

A thermal spray coating device (400) includes a nozzle (402) into which powder is sprayed and a chamber (401) into which powder is injected. For example, the chamber (401) can provide pressure to the nozzle through combustion. The chamber can contain a mixture of a fuel such as acetylene, hydrogen, propane or propylene and a carrier gas such as oxygen. The mixture can be ignited to generate high pressure and create pressure within the chamber (401).

A powder (20) of either a fluorescent substance or a diffuser may be provided to the chamber (401). For example, the powder may be melted from a high-temperature heat source through combustion and may be sprayed at a high speed toward the upper surface of the substrate (110). The powder may collide with the upper surface of the substrate (110). As a result, a fluorescent substance layer may be formed on the substrate (110).

However, it is not limited thereto, and various methods can be applied as thermal spray coating methods, such as powder flame spray, plasma spray, and high velocity oxygen fuel spray (HVOF).

By repeating the spraying of this powder, multiple fluorescent layers can be formed (S220).

FIG. 14 and FIG. 15 are drawings showing examples of applying the fluorescent plate according to the first embodiment to various optical devices.

The optical device may include a phosphor plate and a light source that irradiates light to the phosphor plate. Here, the phosphor plate may be any one of the phosphor plates of the first embodiment and the second embodiment described above.

Referring to FIG. 14, a phosphor plate can be used in a laser module.

The laser module may include a light source, a collimator, a condenser, and a phosphor plate. The light source may be a laser diode (LD) (510).

The collimator (520) can change the light emitted from the laser diode into parallel light. The collimator (520) can be a collimator.

The lens unit (530) can focus light passing through the collimator.

Light passing through the lens unit (530) can be focused on a portion of the fluorescent plate. And light passing through the fluorescent plate can be diffused to the outside. For example, light passing through the fluorescent plate can be white.

Referring to FIG. 15, the phosphor plate can be applied to a lighting device.

The lighting device may include a light source that emits light and a fluorescent plate (100) on which the light is irradiated. The fluorescent plate (100) may be a fluorescent plate according to the first embodiment and the second embodiment.

The light emits light and may be, for example, but is not limited to, an LED chip (610).

The phosphor plate can be placed in the direction in which light is emitted. Light emitted from the LED chip is irradiated to the phosphor plate, and light passing through the phosphor plate can be diffused to the outside.

In this way, the phosphor plate can be applied to a laser module. In addition, the phosphor plate can be applied to various optical devices such as lighting devices including LED packages, vehicle headlamps, etc.

The embodiments of the present invention described above are not limited to the above-described embodiments and the attached drawings, and it will be apparent to a person having prior knowledge in the technical field to which the embodiments of the present invention belong that various substitutions, modifications, and changes are possible within a scope that does not depart from the technical spirit of the embodiments.

100, 100A, 100B: Phosphor Plate
110: Substrate
120: Phosphor layer
121: Phosphor
122: Diffuser
130: Boundary layer

Claims (17)

substrate;
A plurality of phosphor layers including a first phosphor layer disposed on the substrate and a second phosphor layer disposed on the first phosphor layer; and
A first boundary layer is disposed between the first phosphor layer and the second phosphor layer and includes pores;
The refractive index of the plurality of fluorescent layers is different from the refractive index of the first boundary layer,
The above plurality of phosphor layers include at least one of YAG, LuAg and LuYAG,
The above plurality of fluorescent layers include a diffuser,
The above-mentioned dispersant is,
A phosphor plate comprising at least one of Al2O3, TiO2, ZrO2, and Y2O3, SiO2, and having a weight portion of 10 wt% to 30 wt% relative to the phosphor.
In the first paragraph,
A phosphor plate wherein the refractive index of the first boundary layer is 0.5 to 0.6 times the refractive index of the plurality of phosphor layers.
delete delete In the first paragraph,
The thickness of each of the above multiple fluorescent layers is 50 ㎛ to 150 ㎛,
A phosphor plate having a surface roughness of the plurality of phosphor layers of 0.23 ㎛ to 0.27 ㎛.
In the first paragraph,
The above plurality of fluorescent layers further include a third fluorescent layer disposed on the second fluorescent layer,
A phosphor plate further comprising a second boundary layer disposed between the second phosphor layer and the third phosphor layer and including pores.
light source;
A substrate on which light emitted from the light source is irradiated;
A plurality of phosphor layers including a first phosphor layer disposed on the substrate and a second phosphor layer disposed on the first phosphor layer; and
A phosphor plate including a first boundary layer disposed between the first phosphor layer and the second phosphor layer and including pores;
The refractive index of the plurality of fluorescent layers is different from the refractive index of the first boundary layer,
The above plurality of phosphor layers include at least one of YAG, LuAg and LuYAG,
The above plurality of fluorescent layers include a diffuser,
The above-mentioned dispersant is,
An optical device comprising at least one of Al2O3, TiO2, ZrO2, and Y2O3, SiO2, and having a weight portion of 10 wt% to 30 wt% relative to a phosphor.
a step of spraying a fluorescent substance onto a substrate; and
A step of forming multiple fluorescent layers by spraying the fluorescent substance multiple times;
A first boundary layer including pores is disposed between the plurality of fluorescent layers,
The refractive index of the plurality of fluorescent layers is different from the refractive index of the first boundary layer,
The above plurality of phosphor layers include at least one of YAG, LuAg and LuYAG,
The above plurality of fluorescent layers include a diffuser,
The above-mentioned dispersant is,
A method for manufacturing a phosphor plate comprising at least one of Al2O3, TiO2, ZrO2 and Y2O3, SiO2, and having a weight portion of 10 wt% to 30 wt% relative to the phosphor. delete delete delete delete delete delete delete delete delete

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