CN115703963A - Fluorescent sheet, manufacturing method of fluorescent sheet and light-emitting device - Google Patents

Abstract

The fluorescent sheet comprises a substrate and fluorescent powder particles, wherein the fluorescent powder particles are distributed in the substrate, the shape of the fluorescent powder particles is columnar, an included angle smaller than 90 degrees is formed between the columnar extending direction and a light emergent surface of the fluorescent sheet, and the electromagnetic wave resonance frequency of the fluorescent powder particles is 3.85 multiplied by 10 ¹⁴ Hz～7.89×10 ¹⁴ Within the range of Hz. By the mode, the optical expansion amount of the light source can be reduced.

Description

Fluorescent sheet, manufacturing method of fluorescent sheet and light-emitting device

Technical Field

The application belongs to the field of fluorescent light sources, and particularly relates to a fluorescent sheet, a manufacturing method of the fluorescent sheet and a light-emitting device.

Background

The laser fluorescent light source is generally used for projection display systems, and compared with the projection display light source using a traditional high-brightness bulb light source such as UHD (ultra high-definition) and the like, the laser fluorescent light source can realize the advantages of long service life, high efficiency, no pollution and the like; compared with an LED light source, the laser fluorescent light source has the advantages of high brightness and the like, and compared with a pure laser light source, the laser fluorescent light source has no speckle problem and is low in cost.

In the fluorescent sheet for the fluorescent laser light source in the prior art, the fluorescent particles are all particles in random shapes, the excited light-emitting angle characteristic of the fluorescent sheet is in Lambert distribution, and the divergence angle is large.

Disclosure of Invention

The technical problem that this application mainly solved provides a fluorescence piece, fluorescent piece's manufacturing method and illuminator, can reduce the divergence angle when fluorescence escapes the phosphor powder piece mere exit face, obtains the light source that the optical expansion volume is littleer under the same condition of excitation facula size, is favorable to improving the facula luminance of light source then.

In order to solve the above technical problems, the present application provides a phosphor sheet, which includes a substrate and phosphor particles, wherein the phosphor particles are distributed in the substrate, the phosphor particles are in a columnar shape, and form an angle smaller than 90 ° with a light emitting surface of the phosphor sheet along an extending direction of the columnar shape, and an electromagnetic wave resonance frequency of the phosphor particles is 3.85 × 10 ¹⁴ Hz～7.89×10 ¹⁴ Within the range of Hz.

Preferably, the product of the length of the phosphor particles in the extending direction of the columnar shape and the refractive index thereof is in the range of 0.4 to 4 μm.

Preferably, the length of the phosphor particles in the extending direction is greater than twice the width, and the width direction is perpendicular to the extending direction.

Preferably, the extending direction of the phosphor particles forms an angle of 0 to 30 ° with the light emitting surface of the phosphor sheet.

Preferably, in the fluorescent sheet, more than 70% of the total number of the fluorescent powder particles form an included angle of 0-30 degrees with the light emergent surface of the fluorescent sheet.

Preferably, the refractive index of the matrix is smaller than the refractive index of the phosphor particles. Preferably, the difference between the refractive index of the phosphor particles and the refractive index of the matrix is greater than 0.2.

Preferably, the phosphor particles occupy 10-90% by volume of the phosphor sheet.

In order to solve the above technical problem, the present application provides a method for manufacturing a fluorescent sheet, including: preparing columnar phosphor particles having an electromagnetic wave resonance frequency of 3.85 × 10 ¹⁴ Hz～7.89×10 ¹⁴ Within the range of Hz; mixing the fluorescent powder particles and the matrix according to a preset volume ratio; the orientation of the phosphor particles in the matrix is adjusted so that the phosphor particles are able to form an angle of less than 90 DEG with the light exit surface of the finished phosphor sheet along the direction of extension of the columnar shape.

Preferably, the orientation of the phosphor particles in the matrix is adjusted by means of ultrasonic vibration or standing.

In order to solve the above technical problem, the present application provides a light emitting device including the above fluorescent sheet.

The beneficial effect of this application is: different from the prior art, the shape of the phosphor particles in the technical scheme of the application is columnar, and the electromagnetic wave resonance frequency of the phosphor particles is within the range of

3.85×10 ¹⁴ Hz～7.89×10 ¹⁴ Within the range of Hz, the frequency band close to the visible light can make the fluorescence coupled into the phosphor particles easier to resonate. Furthermore, the shape of the phosphor particles is columnar, which is similar to the arrangement of the antenna, according to the radiation direction principle of the antenna, the amplified energy in the phosphor particles can be more concentrated in the direction perpendicular to the extension direction of the phosphor particles, and the phosphor particles form an included angle smaller than 90 degrees with the light emergent surface of the phosphor sheet along the columnar extension direction, so that more energy in the phosphor particles can be radiated through the light emergent surface of the phosphor sheet at a smaller angle, and further the energy ratio in a smaller divergence angle of the light emergent surface of the phosphor sheet is increased, thereby reducing the optical expansion amount of the fluorescence excitation light spot with the same size, and further being beneficial to improving the light spot brightness of the light source.

Drawings

FIG. 1 is a schematic diagram of a fluorescent laser light source display system;

FIG. 2 is a schematic cross-sectional view of an embodiment of a phosphor plate of the present application;

FIG. 3 is a schematic flow chart of a method for manufacturing a phosphor plate according to the present application;

FIG. 4 is a light intensity distribution diagram of an embodiment of a phosphor plate and a Lambertian radiator according to the present application.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples. It is to be noted that the following examples are only illustrative of the present application, and do not limit the scope of the present application. Likewise, the following examples are only some examples and not all examples of the present application, and all other examples obtained by a person of ordinary skill in the art without any inventive step are within the scope of the present application.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the drawings described above, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a fluorescent laser light source display system. As shown in fig. 1, the display system 10 mainly includes a laser display light source 11, an optical engine 12, an imaging lens 13, a screen 14, and optical elements and hardware and software systems. The optical machine 12 further includes a micro display chip 121 and a TIR prism 122, and light emitted from the laser display light source 11 passes through the dodging device and the optical lens to provide uniform illumination light to illuminate the micro display chip 121. The micro display chip 121 may perform pixelated light intensity modulation on the illumination light, thereby forming a display image on the micro display chip 121. The display image is magnified and imaged by the imaging lens, and a large-size display screen is formed on the screen 14.

There are two main technical routes for laser display light sources: one is an RGB three-color laser light source technology adopting a multiband narrow-wavelength semiconductor laser; the other is a fluorescent laser light source technology which adopts a single-waveband semiconductor laser and combines rare earth luminescent materials. Compared with the RGB three-color laser light source, the fluorescent laser light source has the highest brightness comparable to that of the RGB three-color laser light source, and has a significant advantage in cost.

And a single-waveband semiconductor laser with mature technology, lower cost and excellent performance is adopted to excite a high-performance and low-cost fluorescent material, and a wide-color-gamut three-primary-color light source can be realized through a wavelength selection device. The method of adopting the fluorescent laser light source technology of combining the single-waveband semiconductor laser and the rare earth fluorescent material comprises the following steps: the blue laser excites YAG fluorescent powder to obtain yellow fluorescent light, and then the yellow fluorescent light and the unabsorbed laser are mixed and proportioned through colored light to obtain white light.

The inventor of the application finds that in a common fluorescent sheet of a fluorescent laser light source, fluorescent powder particles are in a random granular shape, strong scattering exists in a fluorescent powder layer, the characteristic of the luminous angle of the fluorescent powder layer after being excited shows Lambert distribution, and the divergence angle is large.

In order to improve the technical problem, the present application proposes the following embodiments:

referring to fig. 2, fig. 2 is a schematic cross-sectional view of a phosphor plate according to an embodiment of the present application. As shown in fig. 2, the phosphor sheet 100 includes a substrate 110 and phosphor particles 120; wherein, the phosphor particles 120 are distributed in the substrate 110, the phosphor particles 120 are columnar, and form an angle less than 90 degrees with the light emergent surface of the phosphor sheet 100 along the extending direction of the columnar, and the electromagnetic wave resonance frequency of the phosphor particles 120 is 3.85 × 10 ¹⁴ Hz～7.89×10 ¹⁴ Within the range of Hz.

In the present application, a surface on which excitation light enters the phosphor sheet is defined as a light incident surface, and a surface on which fluorescence is emitted from the phosphor sheet is defined as a light emitting surface. Since the fluorescent material is generally made into a sheet shape, i.e. a fluorescent sheet, when applied, for example, in the case of a transmissive light source, the light incident surface and the light emitting surface can be two opposite planes of the fluorescent sheet; for a reflective light source, the light entrance face and the light exit face may be the same plane of the phosphor sheet. Of course the application is applicable to other forms of light sources or other shapes of fluorescent material.

The shape of the phosphor particles 120 used in the present embodiment is a column, and specifically, the phosphor particles may be a cylinder, an elliptic cylinder, a square long cylinder, a hexagonal long cylinder, an octagonal long cylinder, and the like, and the specific shape is not limited here. The columnar shape can be obtained by controlling the synthesis conditions of the phosphor particles 120.

According to the law of conservation of expansion, under the condition that losses such as scattering and absorption are not considered for an ideal optical system, the optical expansion of a light beam passing through the optical system is unchanged. Wherein, the etendue is a geometric characteristic for describing a light beam with a certain aperture angle and a certain cross-sectional area, and is defined as a product of the cross-sectional area of the light beam and a projection of a spatial solid angle enclosed by the light beam on a normal line of the cross-section. In an actual optical system, when a light beam passes through scattering, absorption, dodging, and the like, the etendue increases to some extent (etendue dilution), and it is impossible to decrease while maintaining the light energy.

In this embodiment, phosphor particles 120 in phosphor sheet 100 lie along the extending direction of the pillar shape such that the extending direction of phosphor particles 120 forms an angle of less than 90 ° with the light exit surface of phosphor sheet 100. The shape of the phosphor particles 120 is columnar, so that the phosphor particles 120 are similar to an optical dipole antenna, and similar to the arrangement of the antenna, according to the radiation direction principle of the antenna, the phosphor can be radiated in the direction perpendicular to the extending direction of the phosphor particles 120, so that more phosphor can be radiated through the light emitting surface of the phosphor plate 100 at a smaller divergence angle, the energy ratio of the light emitting surface of the phosphor plate 100 radiated at a smaller divergence angle is increased, when the size of the excitation light spot is the same, the optical expansion amount of the phosphor excited by the phosphor plate 100 can be reduced, and the light spot brightness of the fluorescent laser light source can be improved.

In this embodiment, the resonant frequency of the electromagnetic wave of the phosphor particles 120 is 3.85 × 10 ¹⁴ Hz～7.89×10 ¹⁴ Within the range of Hz, it can be further set at 4X 10 ¹⁴ Hz～4.6×10 ¹⁴ In the Hz range, i.e. close to the frequency band of visible light. Since light is also an electromagnetic wave, the electromagnetic wave resonance frequency of the phosphor particles 120 is the frequency at which the electromagnetic wave resonates in the phosphor particles. The light applied in the light source is generally in the visible light band, and by making the resonant frequency of the electromagnetic wave of phosphor particle 120 close to the visible light band, the excited phosphor is more easily coupled into phosphor particle 120 to resonate, and then is emitted outward in the antenna radiation direction of phosphor particle 120, i.e., in the direction perpendicular to the extension direction of phosphor particle 120.

Further, in the present embodiment, the product of the length of the phosphor particles 120 in the extending direction of the columnar shape and the refractive index of the phosphor particles 120 is in the range of 0.4 to 4 μm.

The crystal growth shape of the phosphor particles 120 can be controlled by controlling the synthesis conditions of the phosphor particles 120, for example, controlling the synthesis conditions of flux, thermal field environment, or cooling rate during the growth of the phosphor particles 120. In this embodiment, by limiting the synthesis conditions of the phosphor particles 120, the phosphor particles 120 satisfying the above value of the product range of the length of the phosphor particles 120 and the refractive index can be obtained. The refractive index of the phosphor particles is related to the properties of the phosphor particles themselves, and is typically 1.7 to 2.5. By limiting the product value of the length of the phosphor particles 120 in the columnar extending direction and the refractive index of the phosphor particles 120 to be within the range of 0.4-4 μm, the resonant frequency of the electromagnetic waves in the phosphor particles 120 can be made to approach the visible light frequency range, and a relatively good antenna coupling effect can be achieved, so that the energy radiation directivity in the phosphor particles 120 is stronger, further more energy is radiated in the direction perpendicular to the extending direction of the phosphor particles 120, the optical expansion amount of the fluorescence excited by the phosphor plate is reduced, and the light spot brightness of the phosphor light source is increased.

Further, the length of the phosphor particles 120 in the extending direction is greater than twice the width, wherein the width direction is perpendicular to the extending direction.

In this embodiment, the phosphor particles 120 are columnar, the extension distance of the phosphor particles 120 along the extension direction of the columnar shape is the length of the phosphor particles 120, and the extension distance perpendicular to the extension direction of the phosphor particles 120 is the width of the phosphor particles 120, and the ratio of the length to the width of the phosphor particles 120 is limited to be greater than 2 in this embodiment. Satisfying the ratio of the length to the width of the phosphor particles 120 to be greater than 2 provides the phosphor particles 120 with sufficient radiation anisotropy that the fluorescent light tends to radiate in the direction perpendicular to the extension direction, i.e., the width direction. The upper limit of the ratio is generally determined by the manufacturing process of the phosphor particles, and the application is not particularly limited. Further, in one embodiment, the ratio of the length to the width of the phosphor particles 120 may be less than 100, and further may be less than 10.

Further, the extending direction of the phosphor particles 120 forms an angle of 0 to 30 ° with the light emitting surface of the phosphor sheet 100.

In this embodiment, by controlling the manufacturing conditions of the phosphor sheet 100, the extending direction of the phosphor particles 120 in the phosphor sheet 100 can be made to form an angle of 0 to 30 ° with the light emitting surface of the phosphor sheet 100. The smaller the angle between the phosphor particles 120 and the light emitting surface of the phosphor sheet 100 is, the smaller the divergence angle of the fluorescent light is, the smaller the etendue of the excited fluorescence is. Even more advantageously, the included angle may be 0-20 °, and even more advantageously, the included angle may be 0-15 °.

Further, in the application example of the phosphor patch 100, more than 70% of the total number of phosphor particles 120 form an angle of 0-30 ° with the light exit surface of the phosphor patch 100, i.e. the total number of phosphor particles 120 of more than 70% form an angle of 0-30 ° with the light exit surface of the phosphor patch 100. The process of controlling the direction of the phosphor particles 120 in the phosphor sheet 100 has a certain process error, so that the processing process of the phosphor sheet 100 can be controlled, the phosphor particles 120 having an included angle of 0 to 30 degrees with the light emitting surface of the phosphor sheet 100 account for more than 70% of the number of all the phosphor particles 120 in the phosphor sheet 100, the processing difficulty of the phosphor sheet 100 can be reduced, the energy ratio of the excited fluorescence of the phosphor sheet 100 in a smaller divergence angle can be further increased, and the optical expansion amount of the excited fluorescence can be reduced. Furthermore, it is possible to arrange that more than 80% or more than 90%, or even more than 95% of the total number of phosphor particles 120 makes an angle of 0-30 with the light exit surface of the phosphor sheet 100.

Further, the refractive index of the matrix 110 is smaller than the refractive index of the phosphor particles 120 to enable coupling of the phosphor with the phosphor particles 120.

The phosphor particles 120 used in laser display are typically rare earth doped ceramic crystal particles. In this embodiment, where a difference in refractive index between phosphor particles 120 and matrix 110 is desired, and the refractive index of phosphor particles 120 is high, matrix 110 is not preferably configured to have a high refractive index, e.g., matrix 110 may have a refractive index of less than 1.6 or less than 1.5. In some specific application examples, the difference between the refractive indexes of the phosphor particles 120 and the matrix 110 can be set to be greater than 0.2, which can improve the coupling efficiency of the phosphor particles 120 and the fluorescence, so that the phosphor particles 120 and the fluorescence are easier to resonate. The upper limit of the difference in refractive index is determined by the particular type of phosphor particles and matrix used.

In the process of manufacturing the phosphor sheet 100, the material of the matrix 110 needs to have certain fluidity and viscosity, and the phosphor particles 120 can maintain their solid state, so that the phosphor particles 120 can be mixed into the fluid matrix 110, and the matrix 110 doped with the phosphor particles 120 can be restored to the solid state, and then encapsulated to obtain the phosphor sheet 100. The materials of phosphor particles 120 and matrix 110 can be chosen flexibly according to specific application requirements, and are not limited herein.

Further, the material of the substrate 110 may be an organic substrate or an inorganic substrate, and for example, may be any one of silica gel, glass or ceramic, and the silica gel may be organic silica gel or inorganic silica gel. The material of the phosphor particles 120 is not particularly limited, and may be, for example, YAG: ce ³⁺ 、LuAG:Ce ³⁺ 、(Sr,Ca)AlSiN ₃ :Eu ²⁺ Any one of the above.

Further, the present application provides a method for manufacturing a fluorescent sheet, which is used for manufacturing the above fluorescent sheet, please refer to fig. 3, and fig. 3 is a flowchart of the method for manufacturing the fluorescent sheet of the present application. The manufacturing method of the fluorescent sheet comprises the following steps.

S10: columnar phosphor particles are prepared.

In this embodiment, the phosphor particles can be formed into a columnar shape by selecting an appropriate method as needed so that the resonant frequency of the electromagnetic wave in the phosphor particles is 3.85 × 10 ¹⁴ Hz～7.89×10 ¹⁴ Within the range of Hz, i.e. close to the visible frequency band, the specific synthesis method is not limited here. For example, the phosphor particles can be prepared by various methods such as a high-temperature solid phase method, a sol-gel method, a solution combustion method, a hydrothermal method, a microwave method, and a coprecipitation method.

S20: the phosphor particles are mixed with the matrix in a predetermined volume ratio.

In different application examples, the mixing ratio of the matrix and the phosphor particles can be adjusted to obtain a light source with desired effect. In some non-limiting embodiments, the volume ratio of the phosphor particles in the phosphor sheet may be 10-90%, or may be further set to 10-60%.

S30: the orientation of the phosphor particles in the matrix is adjusted so that the phosphor particles form an angle of less than 90 DEG with the light exit surface of the finished phosphor sheet along the direction of extension of the columnar shape.

In step S30, the orientation of the phosphor particles in the matrix can be adjusted by ultrasonic vibration or standing. By setting the mixing conditions, the phosphor particles can be kept in a solid state and have a columnar shape under the conditions, and the matrix has a certain viscosity and fluidity under the conditions, and in this case, the matrix can be in the state of, for example, an uncured silica gel raw material, a molten glass, a slurry formed from a glass or ceramic raw material powder and an auxiliary agent, or the like. When the solid phosphor particles are mixed in a matrix and left to stand or subjected to ultrasonic vibration, the columnar shape of the solid phosphor particles causes the phosphor particles to fall down in the direction of extension due to gravity and viscous resistance.

Specifically, the present application proposes the following examples for different phosphor sheet fabrication methods, based on the shape of the Wen Yingguang powder particles and the orientation requirements in the phosphor sheet, in combination with the material requirements of the phosphor particles and the host.

The first embodiment is mainly used for manufacturing red fluorescent sheets, and the specific implementation steps are as follows.

In this embodiment, first, according to step S10, the phosphor particle composition (Sr, ca) AlSiN is selected ₃ :Eu ²⁺ Wherein rare earth element Eu ²⁺ Has a doping concentration of 0.8% (mole fraction), and a phosphor particle having a grain size of 0.5 μm in extension length in the extension direction and 0.15 μm in extension width in the direction perpendicular to the extension direction was synthesized, wherein the phosphor particle had a light emission center of 600nm.

According to step S20, the matrix is set to be silica gel, and the phosphor particles and the silica gel raw material are blended in a volume ratio of 1:2.

According to step S30, the mixture of the phosphor particles and the silica gel raw material is placed on an ultrasonic platform.

On the ultrasonic platform, the vibration of ultrasonic wave can make the columnar fluorescent powder particles tend to be arranged along the direction parallel to the light emitting surface of the fluorescent sheet along the extending direction of the fluorescent powder particles under the action of gravity and viscous resistance in the silica gel raw material.

In the phosphor sheet obtained by this embodiment, the phosphor particles act like an optical dipole antenna with a high-order component. The specific optical radiation energy distribution is shown in fig. 4, and fig. 4 is a light intensity distribution diagram of the phosphor plate of the present application and a lambertian radiator. It can be observed that the energy occupancy of the phosphor sheet 100 in this embodiment is higher than that of the lambertian radiator in a small divergence angle.

The second embodiment is mainly used for manufacturing yellow fluorescent sheets, and the specific implementation steps are as follows.

In this embodiment, first, according to step S10, the phosphor particles are selected to have a composition of YAG to Ce ³⁺ Rare earth element Ce ³⁺ Has a doping concentration of 1% (mole fraction). Phosphor particles having a grain size of 0.6 μm in length in the extending direction and 0.18 μm in width in the direction perpendicular to the extending direction were synthesized, and the luminescence center of the phosphor particles was 560nm.

According to step S20, the matrix is set to be glass, and phosphor particles are blended with glass frit in a volume ratio of 1:2.

After the glass is melted, the mixture of the phosphor particles and the molten glass is left to stand for one hour according to step S30.

During the standing, the phosphor particles are arranged in a direction in which the extending direction is parallel to the light emitting surface of the phosphor sheet by gravity and viscous resistance in the molten glass, which can obtain the similar effect to the first embodiment. Please refer to fig. 4 for a specific optical radiation energy distribution, which is not described herein.

The application also provides a light-emitting device, which comprises an excitation light source and the fluorescent sheet. The excitation light source can be a laser light source, an LED light source or other suitable light sources, and the fluorescence sheet is irradiated by the excitation light source to generate fluorescence. The Light emitting device can be applied to projection and Display systems, such as a Liquid Crystal Display (LCD), a Digital Light Processing (DLP) or a projector; but also to lighting systems, such as automotive lights; the method can also be applied to the technical field of 3D display. In the light emitting device, the fluorescent sheet may be made into a movable device, such as a color wheel, so that the excitation light source emitted by the excitation light source is incident on the color wheel which rotates, thereby generating fluorescent light.

To sum up, in the technical solution of the present application, the shape of the phosphor particles in the phosphor sheet is a column, and the phosphor particles form an included angle smaller than 90 degrees with the light emergent surface of the phosphor sheet along the extending direction of the column, and the shape of the phosphor particles makes the electromagnetic wave resonance frequency of the phosphor particles approach the frequency of visible light, so that the phosphor particles in the phosphor sheet act as an antenna, and the direction of the phosphor particles is arranged so that the fluorescence coupled into the phosphor particles can be radiated out through the light emergent surface of the phosphor sheet with a smaller divergence angle, thereby reducing the optical expansion of the light, and facilitating to improve the emergent spot brightness of the fluorescent laser light source.

The above embodiments are merely examples and are not intended to limit the scope of the present disclosure, and all modifications, equivalents, and flow charts using the contents of the specification and drawings of the present disclosure, which are directly or indirectly applied to other related technical fields, are included in the scope of the present disclosure.

Claims (11)

1. A phosphor sheet, comprising a substrate and phosphor particles;

the fluorescent powder particles are distributed in the substrate, the shape of the fluorescent powder particles is columnar, an included angle smaller than 90 degrees is formed between the columnar extending direction and the light emergent surface of the fluorescent sheet, and the electromagnetic wave resonance frequency of the fluorescent powder particles is 3.85 multiplied by 10 ¹⁴ Hz～7.89×10 ¹⁴ Within the range of Hz.

2. The phosphor sheet according to claim 1, wherein a product value of a length of said phosphor particles in an extending direction of said columnar shape and a refractive index of said phosphor particles is in a range of 0.4 to 4 μm.

3. The phosphor patch as recited in claim 1, wherein the phosphor particles have a length along the direction of elongation greater than twice a width, wherein the width is oriented perpendicular to the direction of elongation.

4. A phosphor plate as claimed in claim 1, wherein the direction of extension of the phosphor particles is at an angle of 0-30 ° to the light exit face of the phosphor plate.

5. A phosphor plate as claimed in claim 1, wherein more than 70% of the total number of phosphor particles in the phosphor plate are at an angle of 0-30 ° to the light exit surface of the phosphor plate.

6. A phosphor patch as claimed in claim 1, wherein the refractive index of said matrix is smaller than the refractive index of said phosphor particles.

7. A phosphor patch as claimed in claim 6, wherein the difference between the refractive index of the phosphor particles and the refractive index of the matrix is larger than 0.2.

8. The phosphor sheet of claim 1, wherein said phosphor particles occupy 10-90% by volume of the phosphor sheet.

9. A method for manufacturing a fluorescent sheet is characterized by comprising the following steps:

preparing columnar phosphor particles having an electromagnetic wave resonance frequency of 3.85 × 10 ¹⁴ Hz～7.89×10 ¹⁴ Within the range of Hz;

mixing the fluorescent powder particles and the matrix according to a preset volume ratio;

and adjusting the directions of the fluorescent powder particles in the substrate so that the fluorescent powder particles form an included angle of less than 90 degrees with the light emergent surface of the manufactured fluorescent sheet along the extension direction of the columnar shape.

10. The method of claim 9, wherein the direction of the phosphor particles in the matrix is adjusted by ultrasonic vibration or standing.

11. A light-emitting device comprising the fluorescent sheet as set forth in any one of claims 1 to 8.

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