Reflection type wavelength conversion device and preparation method thereof

Abstract

The invention discloses a reflective wavelength conversion device and a preparation method thereof. The device comprises a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are sequentially stacked, the laser diffusion layer comprises a first packaging body and functional phase particles dispersed in the first packaging body, the mass ratio of the functional phase particles to the first packaging body is (1.5-4): 10, the visible light transmittance of the first packaging body is 90% or above, and the visible light transmittance of the second packaging body is 90% or above. The functional phase particles comprise coarse particles and fine particles, the mass ratio of the coarse particles to the fine particles is (0.4-1.2): 1, the median diameter D50 of the coarse particles is 0.1-0.4 [mu] m, the median diameter D50 of the fine particles is 0.01-0.05 [mu] m, the laser diffusion layer is used for scattering incident laser and enabling part of the laser to continue to advance in the incident direction, and the other part of the laser to advance in the direction opposite to the incident direction. On the premise that a laser diffusion light path is not newly added, the light source cost is saved and the light source size is reduced, through the microstructure design of the laser diffusion layer, the problem that light beams of a reflective laser illumination light source are blue in the center and yellow in the periphery is solved.

Description

Technical Field

[0001] The present invention belongs to the field of laser lighting and display technology, and specifically relates to a reflective wavelength conversion device and a preparation method thereof. Background Art

[0002] As an advanced lighting technology, laser light sources play an increasingly important role in the field of modern lighting. Its working principle is: the incident laser excites the wavelength conversion material inside the light source to produce yellow light, and the yellow light produced by the excitation combines with the remaining blue light after the excitation to finally obtain white light for illumination. Lasers have the advantages of high power density and small angles, which enable laser light sources to provide higher white light illumination at the same power, usually more than 7 times that of LED light sources, so the irradiation distance is longer, which is particularly suitable for ultra-long-distance lighting scenes, such as large stadiums, highway lighting, etc.

[0003] According to the relative relationship between the laser light emitting direction and the laser incident direction, laser light sources can be divided into reflective laser light sources and transmissive laser light sources. The light emitting direction of the reflective laser light source after the wavelength conversion device is opposite to the incident direction of the excitation light. This design makes the light source brighter, but it also brings the problem of complex structure. The reflective laser light source contains more lenses and other optical components, which not only increases the volume of the light source, but also increases the production cost. Therefore, reflective laser light sources are usually used in high laser power and high brightness lighting occasions, such as large stage lighting, movie projection, etc. These occasions have high requirements on the brightness of the light source, and are not very sensitive to cost, and can bear the higher production cost of reflective laser light sources.

[0004] However, both reflective and transmissive laser light sources face the problem of Gaussian distribution of laser energy. In the illumination light source with LD laser as the excitation light source, the excitation light energy is Gaussian distributed, that is, the blue laser energy in the center of the light spot is high, while the blue laser energy away from the center of the light spot gradually decreases. This uneven energy distribution phenomenon will cause the fluorescent light beam generated by the wavelength conversion material inside the light source to also show unevenness. Specifically, the proportion of blue light in the light at the center of the laser irradiation is high, while the proportion of blue light away from the center is small. This color difference of light will form a "yellow aperture" phenomenon in the illumination area, that is, the center of the light spot is white or blue, while the surrounding area is yellow. This phenomenon greatly affects the uniformity of the light spot and reduces the lighting effect.

[0005] In order to solve the above problems, some clever optical designs are used in the prior art. For example, in the reflective light source, the blue light is split by a dichroic mirror; most of the blue light is used to excite the wavelength conversion material to produce stimulated yellow light, and the remaining blue light in this part of the blue light combines with the stimulated yellow light, showing a distribution characteristic of central blue and surrounding yellow; at the same time, a small proportion of blue light is used to excite the blue light scattering powder to produce non-Gaussian blue light, and this part of the non-Gaussian blue light scattered by the scattering powder combines with the stimulated yellow light, thereby significantly improving the overall beam effect of the light source. Through this design, the beam quality of the light source is optimized and the uniformity of the light spot is improved. However, this technical solution also brings some new problems. First, the introduction of the blue light scattering part increases the number of optical lenses and structural parts, which leads to an increase in the cost of the light source. Secondly, the increase in the number of optical parts and structural parts also increases the volume of the light source, so that the light source requires more space during the design and installation process. These problems have limited the promotion of this technical solution in practical applications to a certain extent. Summary of the invention

[0006] The present invention aims to overcome at least one defect in the prior art and provide a reflective wavelength conversion device, which solves the pain point of the reflective laser lighting light source beam being "blue in the center and yellow around" without adding a new laser to break up the light path, saving light source costs, and reducing the volume of the light source.

[0007] In order to solve the above technical problems, the following technical solutions are adopted: In the first aspect, a reflective wavelength conversion device is proposed. The device includes a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence, the laser diffusion layer includes a first package and functional phase particles dispersed in the first package, the mass ratio of the functional phase particles to the first package is (1.5-4):10, the visible light transmittance of the first package is above 90%, the functional phase particles include coarse particles and fine particles, the mass ratio of the coarse particles to the fine particles is (0.4-1.2):1, the median diameter D50 of the coarse particles is 0.1-0.4 μm, and the median diameter D50 of the fine particles is 0.01-0.05 μm, the laser diffusion layer is used to scatter the incident laser, and make part of the laser continue to travel along the incident direction, while the other part of the laser travels in the direction opposite to the incident direction.

[0008] This solution solves the pain point of "blue in the center and yellow around" of the reflective laser lighting source light beam through the microstructure design of the laser diffusion layer, without adding a new laser to break up the light path, saving the cost of the light source, and reducing the volume of the light source. Specifically, the functional phase particles of different particle size ranges inside the laser diffusion layer will appropriately break up the incident Gaussian laser, and the coarse particles will have a strong Mie scattering effect, causing part of the laser to be scattered at a large angle, prompting this part of the laser to return in a direction roughly opposite to the incident direction. Due to the scattering of the functional phase particles, this part of the reflected laser no longer presents a strong Gaussian shape, but a weak Gaussian distribution or even a flat-angle distribution characteristic. This part of the laser is homogenized, and the laser light intensity at different angles becomes a distribution similar to that of LED light. At the same time, the fine particles will have a Rayleigh weak scattering effect on the incident Gaussian laser, causing this part of the laser to be small. Angle scattering, the laser divergence angle increases appropriately, but this part of the laser generally continues to travel in the direction roughly the same as the incident direction, enters the wavelength conversion layer, excites the fluorescent material inside the wavelength conversion layer, and generates stimulated fluorescence. The stimulated fluorescence and the remaining laser that has not been converted are reflected by the fluorescent reflection layer, and then enter the laser diffusion layer from the wavelength conversion layer, and are scattered by the laser diffusion layer. The orientation is more scattered and homogenized, and combined with the reflected laser that is scattered by the laser diffusion layer and returns in the opposite direction of the laser incident direction, and finally emerges from the laser diffusion layer and enters the air medium, forming a white light with a uniform distribution of light beams. This reflective wavelength conversion device can support and be applied to the development of reflective high-power SMD white laser light sources.

[0009] The wavelength conversion layer includes a second package and phosphor particles dispersed in the second package. The mass ratio of the phosphor particles to the second package is preferably (2-10):1. The visible light transmittance of the second package is preferably 90% or more. The particle size of the phosphor particles is preferably 10-20 μm. The wavelength conversion layer preferably includes scattering particles dispersed in the second package. The mass ratio of the scattering particles to the phosphor particles is preferably (1-25):100, more preferably (10-25):100. The particle size of the scattering particles is preferably 0.01-0.3 μm, more preferably 0.1-0.3 μm. The introduction of scattering particles can further increase the strayness of stimulated fluorescence and residual laser light, thereby enhancing the uniformity of light beam distribution. By selecting the particle size range of the scattering particles and adjusting the ratio of the scattering particles to the phosphor particles and the second package, high light efficiency can be ensured, and the light can be scattered to further evenly distribute the light.

[0010] The material of the first package is preferably any one of organic silica gel, inorganic siloxane, and glass powder, and more preferably glass powder with a refractive index of less than 1.6 and a full melting temperature of 550-750°C. The material of the second package is preferably any one of organic silica gel, inorganic siloxane, and glass powder, and more preferably glass powder with a refractive index of less than 1.6 and a full melting temperature of 650-850°C. If glass powder is used as the material of both the first package and the second package, the full melting temperature of the glass powder used in the first package is preferably less than or equal to the full melting temperature of the glass powder used in the second package.

[0011] The material of the functional phase particles is preferably at least one of aluminum oxide, zinc oxide, magnesium oxide, titanium oxide, and lithopone. The material of the phosphor particles is preferably at least one of yellow powder, green powder, and red powder. The material of the scattering particles is preferably at least one of titanium oxide, aluminum oxide, magnesium oxide, zinc oxide, zirconium oxide, tantalum oxide, lithopone, and barium sulfate powder.

[0012] The fluorescent reflective layer is preferably any one of a metal reflective layer and a dielectric film reflective layer. The material of the metal reflective layer is preferably any one of silver, aluminum, and aluminum-silver alloy. The material of the dielectric film reflective layer is preferably a stacked structure of tantalum oxide and silicon oxide or a stacked structure of titanium oxide and silicon oxide. The metal reflective layer can be attached to one side of the heat sink substrate by coating, or can be bonded to one side of the heat sink substrate by high-temperature sintering, preferably bonded to one side of the heat sink substrate by high-temperature sintering.

[0013] The room temperature thermal conductivity of the heat sink substrate is preferably greater than 30w / (m·k). The heat sink substrate is preferably any one of a ceramic substrate and an inorganic substrate. The ceramic substrate is preferably an aluminum nitride substrate, a silicon carbide substrate, a silicon nitride substrate, or a sapphire substrate. The inorganic substrate is preferably any one of a single crystal silicon substrate, a polycrystalline or single crystal diamond substrate.

[0014] The thickness of the laser diffusion layer is preferably 5 to 40 μm, more preferably 8 to 30 μm. The thickness of the wavelength conversion layer is preferably 30 to 120 μm, more preferably 40 to 120 μm. The thickness of the heat sink substrate is preferably 0.5 to 3 mm. The fluorescent reflection layer is a sintered metal reflection layer, and the thickness of the sintered metal reflection layer is preferably 10 to 30 μm, or the fluorescent reflection layer is a metal-plated reflection layer, and the thickness of the metal-plated reflection layer is preferably 100 to 1000 nm, or the fluorescent reflection layer is a dielectric film reflection layer, and the thickness of the dielectric film reflection layer is preferably 5 to 8 μm.

[0015] In a second aspect, a method for preparing the above-mentioned reflective wavelength conversion device is proposed. The method comprises the following steps: (1) A dielectric film reflective layer is coated on the surface of the heat sink substrate: a dielectric film reflective layer is attached to the surface of the heat sink substrate by evaporation; (2) Preparing wavelength conversion layer slurry: adding phosphor particles and the second encapsulation body to a grinding device, adding an organic solvent, stirring evenly, and then transferring the mixed slurry to a stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining a wavelength conversion layer slurry; (3) The side of the heat sink substrate covered with the dielectric film reflective layer is coated with a wavelength conversion layer: the wavelength conversion layer slurry is coated on the side of the heat sink substrate covered with the dielectric film reflective layer by a screen printing process to obtain a wavelength conversion layer wet film; then, it is baked in a baking oven at a temperature of 100-130°C for 30-60 minutes to obtain a wavelength conversion layer dry film; finally, it is sintered in a sintering furnace at 800-900°C for 30-120 minutes to ensure that the wavelength conversion layer is firmly bonded to the surface of the heat sink substrate; (4) Preparing laser diffusion layer slurry: according to the designed ratio, the coarse particles, fine particles and the first encapsulation body of the functional phase particles are added to the grinding device, and the organic solvent is added and stirred evenly. Then, the mixed slurry is transferred to the stirring device and continued to be stirred and debubbled until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining the laser diffusion layer slurry; (5) The side of the heat sink substrate covered with the wavelength conversion layer is covered with a laser diffusion layer: a laser diffusion layer slurry is coated on the side of the heat sink substrate covered with the wavelength conversion layer by a screen printing process to obtain a wet film of the laser diffusion layer; then, the film is baked in a baking oven at a temperature of 100 to 130°C for 30 to 60 minutes to obtain a dry film of the laser diffusion layer; finally, the film is sintered in a sintering furnace at a temperature of 700 to 800°C for 30 to 120 minutes to ensure that the laser diffusion layer is firmly bonded to the surface of the heat sink substrate, thereby obtaining the reflective wavelength conversion device; Or, the preparation method comprises the following steps: (1) Preparing metal reflective layer slurry: adding metal powder and glass powder into a grinding device, then adding an organic solvent, stirring evenly, then transferring the mixed slurry to a stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining a metal reflective layer slurry; (2) Covering the surface of the heat sink substrate with a sintered metal reflective layer: Using a steel screen printing process, a layer of metal reflective layer slurry is coated on the surface of the heat sink substrate to obtain a sintered metal reflective layer wet film; then, it is baked in a baking oven at a temperature of 100~130℃ for 30~60min to obtain a sintered metal reflective layer dry film; finally, it is sintered in a sintering furnace at 850~900℃ for 30~60min to ensure that the sintered metal reflective layer is firmly bonded to the surface of the heat sink substrate; (3) Preparing wavelength conversion layer slurry: adding phosphor particles and the second encapsulation body to a grinding device, adding an organic solvent, stirring evenly, and then transferring the mixed slurry to a stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining a wavelength conversion layer slurry; (4) The side of the heat sink substrate covered with the sintered metal reflective layer is covered with a wavelength conversion layer: the wavelength conversion layer slurry is coated on the side of the heat sink substrate covered with the sintered metal reflective layer by a screen printing process to obtain a wavelength conversion layer wet film; then, the wavelength conversion layer is baked in a baking oven at a temperature of 100-130°C for 30-60 minutes to obtain a wavelength conversion layer dry film; finally, the wavelength conversion layer is sintered in a sintering furnace at 800-850°C for 30-120 minutes to ensure that the wavelength conversion layer is firmly bonded to the surface of the heat sink substrate; (5) Preparing laser diffusion layer slurry: according to the designed ratio, the coarse particles, fine particles and the first encapsulation body of the functional phase particles are added to the grinding device, and the organic solvent is added and stirred evenly. Then, the mixed slurry is transferred to the stirring device and continued to be stirred and debubbled until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining the laser diffusion layer slurry; (6) The wavelength conversion layer-covered side of the heat sink substrate is covered with a laser diffusion layer: the laser diffusion layer slurry is coated on the wavelength conversion layer-covered side of the heat sink substrate by screen printing to obtain a wet film of the laser diffusion layer; then, the laser diffusion layer is baked in a baking oven at a temperature of 100 to 130°C for 30 to 60 minutes to obtain a dry film of the laser diffusion layer; finally, the laser diffusion layer is sintered in a sintering furnace at a temperature of 700 to 800°C for 30 to 120 minutes to ensure that the laser diffusion layer is firmly bonded to the surface of the heat sink substrate, thereby obtaining the reflective wavelength conversion device of this case.

[0016] Compared with the prior art, this solution has the following beneficial effects: Under the premise of not adding new laser to scatter the light path, saving the cost of the light source, and reducing the volume of the light source, this solution uses the microstructure design of the laser diffusion layer to make the incident laser be properly scattered by the functional phase particles in two particle size ranges. Most of the laser light is scattered by fine particles at a small angle and continues to enter the wavelength conversion layer to generate stimulated fluorescence and residual laser light, ensuring that the wavelength conversion device still has a strong light efficiency, while a small part of the laser light is scattered by coarse particles at a large angle and returns to form reflected laser light, which compensates and combines the stimulated fluorescence and residual laser light reflected by the fluorescent reflection layer to the laser diffusion layer. Moreover, the stimulated fluorescence and residual laser light will also be further scattered by the laser diffusion layer, effectively improving the beam quality and forming a uniformly distributed white light beam, thereby solving the pain point problem of the "blue center and yellow surroundings" of the reflective laser lighting light source beam, and can support and be applied to the development of reflective high-laser power SMD white laser light sources. DETAILED DESCRIPTION

[0017] The reflective wavelength conversion device proposed in this solution includes a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence.

[0018] The laser diffusion layer mainly plays the role of breaking up and transmitting a large amount of laser light and reflecting a small amount of laser light. It is basically composed of the first package and the functional phase particles dispersed in the first package. The thickness is preferably 5-40 μm, more preferably 8-30 μm. The mass ratio of the functional phase particles to the first package is preferably (1.5-4):10.

[0019] Functional phase particles include particles of two particle size ranges, namely coarse particles and fine particles. The median diameter of the coarse particles is D50 = 0.1~0.4μm, and the median diameter of the fine particles is D50 = 0.01~0.05μm. The mass ratio of coarse particles to fine particles is preferably (0.4~1.2):1. A certain amount of coarse particles has a Mie strong scattering effect on the incident Gaussian laser, causing part of the laser to scatter at a large angle and travel in a direction roughly opposite to the incident direction to form a reflected laser. Due to the disorder of the scattering direction, the reflected laser no longer presents a strong Gaussian form, but a weak Gaussian form, or even a flat-angle distribution characteristic. This part of the laser is homogenized, and the laser light intensity at different angles is uniformly distributed like LED light. A certain amount of fine particles has a Rayleigh weak scattering effect on the incident Gaussian laser, causing this part of the laser to scatter at a small angle and continue to travel in a direction roughly the same as the incident direction to form a transmitted laser. Since fine particles have limited effect on laser scattering, the divergence angle of most transmitted lasers will not be too large. The transmitted laser maintains a certain strong Gaussian shape and participates in the subsequent excitation of the wavelength conversion material, ensuring that the wavelength conversion device still has a strong light effect. By adjusting the type, particle size, and coarse-fine particle ratio of the functional phase particles, the ratio of the functional phase particles to the first package, and the thickness of the laser diffusion layer, the ratio of the reflected laser to the transmitted laser can be quantitatively adjusted, so that a large amount of laser is transmitted, and the transmitted laser participates in the excitation of the wavelength conversion layer to ensure the luminous efficiency of the wavelength conversion device, while a small amount of laser is reflected, and the reflected laser compensates and combines the fluorescent light beam generated by the excitation, effectively improving the uniformity of the light spot and the quality of the beam.

[0020] The functional phase particles can be made of at least one material selected from aluminum oxide, zinc oxide, magnesium oxide, titanium oxide, and lithopone, and the first package can be made of a material with a visible light transmittance of more than 90%, such as organic silica gel, inorganic siloxane, glass powder, etc. The first package is preferably made of glass powder, the refractive index of the glass powder is preferably less than 1.6, and the full melting temperature is preferably 550-750°C.

[0021] The wavelength conversion layer mainly receives laser excitation and generates stimulated fluorescence. It is basically composed of a second package and phosphor particles dispersed in the second package. The thickness is preferably 30-120 μm, and more preferably 40-120 μm. Among them, the mass ratio of phosphor particles to the second package is preferably (2-10):1, and the particle size of phosphor particles is preferably 10-20 μm. Most of the transmitted laser light scattered at a small angle and passing through the laser diffusion layer excites the phosphor particles to generate stimulated fluorescence, and a small part fails to reach the phosphor particles to form residual laser light. The stimulated fluorescence is mixed with the residual laser light to form mixed light. Due to the small-angle scattering of the transmitted laser by the laser diffusion layer, the strayness of the mixed light is increased to a certain extent, and the uniformity of the beam distribution is enhanced.

[0022] In addition to the phosphor particles and the encapsulation particles, the wavelength conversion layer is preferably also dispersed with a certain amount of scattering particles, the mass ratio of the scattering particles to the phosphor particles is preferably (1-25):100, more preferably (10-25):100, and the particle size of the scattering particles is preferably 0.01-0.3 μm, more preferably 0.1-0.3 μm. A certain amount of scattering particles can further increase the strayness of the mixed light, so that the uniformity of the light beam distribution is further enhanced. By selecting a suitable particle size range and adjusting the ratio of scattering particles, phosphor particles, and the second encapsulation, it is possible to ensure high light efficiency and to disperse the light, so that the mixed light is further evenly distributed.

[0023] Phosphor particles can be selected from (Y, Gd)3(Al, Ga)5O 12 :Ce, α-Sialon:Eu and other yellow powders, LuAG, GaYAG, β-Sialon:Eu and other green powders, CaAlSiN3:Eu and other red powders, and mixed powders of yellow powder, green powder and red powder can also be selected; scattering particles can be selected from at least one material selected from titanium oxide, aluminum oxide, magnesium oxide, zinc oxide, zirconium oxide, tantalum oxide, lead powder, barium sulfate powder, etc.; the second package can be selected from materials with a visible light transmittance of more than 90%, such as organic silica gel, inorganic siloxane, glass powder, etc., preferably glass powder, the refractive index of the glass powder is preferably less than 1.6, and the full melting temperature is preferably 650~850℃. If both the first package and the second package use glass powder, the full melting temperature of the glass powder used in the first package is preferably not more than the full melting temperature of the glass powder used in the second package.

[0024] The fluorescent reflection layer can be a metal reflection layer or a dielectric film reflection layer, which mainly reflects the stimulated fluorescence and the residual laser. After the mixed light generated by the wavelength conversion layer is reflected by the fluorescent reflection layer, it returns in a direction roughly opposite to the incident direction and is incident on the laser diffusion layer again, and is scattered twice inside the laser diffusion layer, making the light more chaotic and more uniform. Finally, it is mixed with the reflected laser generated by the laser diffusion layer to obtain a uniform white light beam. The material of the metal reflection layer is preferably any one of silver, aluminum, and aluminum-silver alloy. It can be attached to the polished surface of the heat sink substrate by coating, or it can be bonded to one side of the heat sink substrate by high-temperature sintering, preferably bonded to one side of the heat sink substrate by high-temperature sintering. The metal reflection layer obtained by coating is a metal-plated reflection layer, and the thickness is preferably 100~1000nm. The metal reflection layer obtained by high-temperature sintering and bonding is a sintered metal reflection layer, and the thickness is preferably 10~30μm. The material of the dielectric film reflection layer is preferably a stacked structure of tantalum oxide and silicon oxide or a stacked structure of titanium oxide and silicon oxide, and the thickness is preferably 5~8μm. Preferably, the fluorescent reflective layer is a dielectric film reflective layer or a sintered metal reflective layer. These two structures can be used with fluorescent glass or fluorescent ceramics as the wavelength conversion layer, and the wavelength conversion device will have a stronger ability to withstand laser power. The metal-plated reflective layer needs to be matched with an organic fluorescent layer, and its high temperature resistance and high laser power resistance performance are worse.

[0025] The heat sink substrate plays a role in heat conduction and heat dissipation, and conducts the heat generated internally by the laser diffusion layer and the wavelength conversion layer when they are working to the radiator or the air. The heat sink substrate can be made of a material with a room temperature thermal conductivity exceeding 30w / (m·k), preferably a ceramic substrate or an inorganic substrate, such as an aluminum nitride substrate, a silicon carbide substrate, a silicon nitride substrate, a sapphire substrate, a single crystal silicon substrate, a polycrystalline, a single crystal diamond substrate, etc., and the thickness is preferably 0.5~3mm. If the fluorescent reflective layer is attached to the surface of the heat sink substrate by coating, the surface of the heat sink substrate needs to be polished, and the surface roughness of the polished surface Ra≤0.02μm; if the fluorescent reflective layer is attached to the surface of the heat sink substrate by high-temperature sintering, the surface of the heat sink substrate can be polished without polishing, and only fine grinding is performed to ensure that the surface roughness Ra≤5μm.

[0026] When the dielectric film reflective layer is used as the fluorescent reflective layer, the preparation method comprises the following steps: (1) A dielectric film reflective layer is coated on the surface of the heat sink substrate: A dielectric film reflective layer is attached to the surface of the heat sink substrate by evaporation.

[0027] (2) Prepare wavelength conversion layer slurry: add phosphor particles, second encapsulation body, scattering particles (if any) to a grinding device, add organic solvent, stir evenly, then transfer the mixed slurry to a stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed to obtain wavelength conversion layer slurry. Preferably, scattering particles are added to the mixed slurry. Preferably, the organic solvent is pineneol, and the amount used is 20-30wt% of the total amount of powder.

[0028] (3) The side of the heat sink substrate covered with a dielectric film reflective layer is coated with a wavelength conversion layer: the wavelength conversion layer slurry is coated on the side of the heat sink substrate covered with a dielectric film reflective layer by a screen printing process to obtain a wet film of the wavelength conversion layer; then, the film is baked in a baking oven at a temperature of 100 to 130°C for 30 to 60 minutes to obtain a dry film of the wavelength conversion layer; finally, the film is sintered in a sintering furnace at 800 to 900°C for 30 to 120 minutes to ensure that the wavelength conversion layer is firmly bonded to the surface of the heat sink substrate.

[0029] (4) Preparation of laser diffusion layer slurry: Add the coarse particles, fine particles and first encapsulation of the functional phase particles to the grinding device according to the designed ratio, add the organic solvent, stir evenly, and then transfer the mixed slurry to the stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed to obtain the laser diffusion layer slurry. The organic solvent is preferably pinene alcohol, and the amount used is 40-50wt% of the total powder.

[0030] (5) The wavelength conversion layer-covered side of the heat sink substrate is covered with a laser diffusion layer: a screen printing process is used to coat the laser diffusion layer slurry on the wavelength conversion layer-covered side of the heat sink substrate to obtain a laser diffusion layer wet film; then, the laser diffusion layer is baked in a baking oven at a temperature of 100 to 130°C for 30 to 60 minutes to obtain a laser diffusion layer dry film; finally, the laser diffusion layer is sintered in a sintering furnace at 700 to 800°C for 30 to 120 minutes to ensure that the laser diffusion layer is firmly bonded to the surface of the heat sink substrate, thereby obtaining the reflective wavelength conversion device.

[0031] When a sintered metal reflective layer is used as the fluorescent reflective layer, the preparation method comprises the following steps: (1) Prepare the metal reflective layer slurry: add metal powder and glass powder into a grinding device, then add an organic solvent, stir evenly, then transfer the mixed slurry to a stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed to obtain the metal reflective layer slurry. The organic solvent is preferably pine alcohol, and the amount used is 15-25wt% of the total amount of the powder.

[0032] (2) Covering the surface of the heat sink substrate with a sintered metal reflective layer: A layer of metal reflective layer slurry is coated on the surface of the heat sink substrate using a steel screen printing process to obtain a sintered metal reflective layer wet film; then, it is baked in a baking oven at a temperature of 100-130°C for 30-60 minutes to obtain a sintered metal reflective layer dry film; finally, it is sintered in a sintering furnace at 850-900°C for 30-60 minutes to ensure that the sintered metal reflective layer is firmly bonded to the surface of the heat sink substrate.

[0033] (3) Prepare wavelength conversion layer slurry: add phosphor particles, second encapsulation body, scattering particles (if any) to a grinding device, add organic solvent, stir evenly, then transfer the mixed slurry to a stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed to obtain wavelength conversion layer slurry. Preferably, scattering particles are added to the mixed slurry. Preferably, the organic solvent is pineneol, and the amount used is 20-30wt% of the total amount of powder.

[0034] (4) The side of the heat sink substrate covered with the sintered metal reflective layer is covered with a wavelength conversion layer: the wavelength conversion layer slurry is coated on the side of the heat sink substrate covered with the sintered metal reflective layer by a screen printing process to obtain a wet film of the wavelength conversion layer; then, the film is baked in a baking oven at a temperature of 100 to 130°C for 30 to 60 minutes to obtain a dry film of the wavelength conversion layer; finally, the film is sintered in a sintering furnace at 800 to 850°C for 30 to 120 minutes to ensure that the wavelength conversion layer is firmly bonded to the surface of the heat sink substrate.

[0035] (5) Preparation of laser diffusion layer slurry: Add the coarse particles, fine particles and first encapsulation of the functional phase particles to the grinding device according to the designed ratio, add the organic solvent, stir evenly, and then transfer the mixed slurry to the stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed to obtain the laser diffusion layer slurry. The organic solvent is preferably pine oil, and the amount used is 40-50wt% of the total powder.

[0036] (6) The wavelength conversion layer-covered side of the heat sink substrate is covered with a laser diffusion layer: the laser diffusion layer slurry is coated on the wavelength conversion layer-covered side of the heat sink substrate by screen printing to obtain a wet film of the laser diffusion layer; then, the laser diffusion layer is baked in a baking oven at a temperature of 100 to 130°C for 30 to 60 minutes to obtain a dry film of the laser diffusion layer; finally, the laser diffusion layer is sintered in a sintering furnace at a temperature of 700 to 800°C for 30 to 120 minutes to ensure that the laser diffusion layer is firmly bonded to the surface of the heat sink substrate, thereby obtaining the reflective wavelength conversion device of this case.

[0037] In order to allow those skilled in the art to better understand this scheme, the scheme is further described in detail below in conjunction with specific examples. The process methods used in the examples are conventional methods unless otherwise specified; the materials used are commercially available unless otherwise specified. The amounts used in the examples are by weight unless otherwise specified.

[0038] Example 1 The reflective wavelength conversion device of this embodiment includes a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence.

[0039] The laser diffusion layer is mainly composed of the first package and functional phase particles dispersed in the first package. The mass ratio of the functional phase particles to the first package is 2.8:10, and the thickness of the laser diffusion layer is 20μm. The functional phase particles are aluminum oxide particles, including coarse particles with a median diameter of D50 = 0.2μm and fine particles with a median diameter of D50 = 0.02μm. The mass ratio of coarse particles to fine particles is 0.8:1. The first package uses glass powder with a refractive index of less than 1.6 and a full melting temperature of about 700℃.

[0040] The wavelength conversion layer is mainly composed of the second package body and the phosphor particles and scattering particles dispersed in the second package body. The mass ratio of scattering particles to phosphor particles is 15:100, the mass ratio of phosphor particles to the second package body is 5:1, and the thickness of the wavelength conversion layer is 80μm. The phosphor particles are α-Sialon:Eu yellow powder particles with a particle size of 10μm, the scattering particles are aluminum oxide particles with a particle size of 0.1μm, and the second package body is made of glass powder, with a full melting temperature of about 750℃.

[0041] The fluorescent reflection layer adopts a sintered silver reflection layer, which is mainly composed of silver powder and attached to the heat sink substrate by high-temperature sintering. The thickness is 20μm. Specifically, the sintered silver reflection layer is obtained by sintering silver powder with a particle size of about 4μm, glass powder and pine alcohol at a mass ratio of 98:2:20 at a high temperature of 850~900℃.

[0042] The heat sink substrate is an aluminum nitride substrate with a thickness of 1 mm and at least one side is finely ground, and the surface roughness of the finely ground surface is Ra≤5μm.

[0043] The reflective wavelength conversion device is prepared according to the following steps: (1) Preparation of silver reflective layer slurry: Add silver powder and glass powder into a mortar according to a set ratio, then add 20 wt% of pine oil to the total amount of powder, grind manually for 30 min and stir evenly, then transfer the mixed slurry to a planetary stirring device and continue stirring to remove bubbles until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining a silver reflective layer slurry.

[0044] (2) Sintering the silver reflective layer on the surface of the heat sink substrate: A layer of silver reflective layer slurry is coated on the surface of the heat sink substrate by using a steel screen printing process. By controlling the steel screen thickness and printing process parameters, a silver reflective layer wet film of a preset thickness is obtained. Subsequently, the silver reflective layer is baked in a baking oven at a temperature of 100-130°C for 30-60 minutes to volatilize the pine oil inside the silver reflective layer wet film and obtain a sintered silver reflective layer dry film. Finally, the silver reflective layer is sintered in a sintering furnace at 850-900°C for 30-60 minutes to melt the glass powder inside the silver reflective layer, so that the sintered silver reflective layer is firmly bonded to the surface of the heat sink substrate.

[0045] (3) Prepare wavelength conversion layer slurry: Add phosphor particles, second encapsulation body and scattering particles into a mortar according to the set ratio, add 25wt% of pine oil to the total powder, grind manually for 30 minutes and stir evenly, then transfer the mixed slurry to a planetary stirring device and continue stirring to remove bubbles until the powder particles in the mixed slurry are evenly dispersed to obtain wavelength conversion layer slurry.

[0046] (4) The heat sink substrate is covered with a sintered silver reflective layer on one side and a wavelength conversion layer on the other side: the wavelength conversion layer slurry is coated on the heat sink substrate on the sintered metal reflective layer by screen printing, and a wavelength conversion layer wet film of a preset thickness is obtained by controlling the screen parameters and printing process parameters; then, the wet film is baked in a baking oven at a temperature of 100-130°C for 30-60 minutes to volatilize the pine oil in the wet film of the wavelength conversion layer; finally, the wet film is sintered in a sintering furnace at a temperature of 800-850°C for 30-120 minutes to melt the second encapsulation body in the wavelength conversion layer, so that the wavelength conversion layer is firmly bonded to the surface of the heat sink substrate.

[0047] (5) Preparation of laser diffusion layer slurry: According to the designed ratio, the coarse particles, fine particles and the first encapsulation of the functional phase particles are added to the grinding device, and 45 wt% of the total powder amount of pine oil is added. The mixture is manually ground for 30 min and stirred evenly. The mixed slurry is then transferred to a planetary stirring device and continued to be stirred to remove bubbles until the powder particles in the mixed slurry are evenly dispersed to obtain the laser diffusion layer slurry.

[0048] (6) The wavelength conversion layer-covered side of the heat sink substrate is covered with a laser diffusion layer: a screen printing process is used to coat the laser diffusion layer slurry on the wavelength conversion layer-covered side of the heat sink substrate, and a laser diffusion layer wet film of a preset thickness is obtained by controlling the screen parameters and the printing process parameters; then, the laser diffusion layer is baked in a baking oven at a temperature of 100 to 130°C for 30 to 60 minutes to volatilize the pine oil inside the laser diffusion layer wet film, thereby obtaining a laser diffusion layer dry film; finally, the laser diffusion layer is sintered in a sintering furnace at a temperature of 700 to 800°C for 30 to 120 minutes to melt the first packaging body inside the laser diffusion layer, so that the laser diffusion layer is firmly bonded to the surface of the heat sink substrate, thereby obtaining the reflective wavelength conversion device of this case.

[0049] Example 2 The reflective wavelength conversion device of this embodiment includes a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence.

[0050] The laser diffusion layer is mainly composed of the first package and functional phase particles dispersed in the first package. The mass ratio of the functional phase particles to the first package is 1.5:10, and the thickness of the laser diffusion layer is 40μm. The functional phase particles are aluminum oxide particles, including coarse particles with a median diameter of D50 = 0.4μm and fine particles with a median diameter of D50 = 0.05μm. The mass ratio of coarse particles to fine particles is 1:1. The first package uses glass powder with a refractive index of less than 1.6 and a full melting temperature of about 700℃.

[0051] The wavelength conversion layer is the same as that in Example 1.

[0052] The fluorescent reflecting layer is the same as that in Example 1.

[0053] The heat sink substrate is the same as that in Example 1.

[0054] Except for the thickness of the laser diffusion layer and the amount of each raw material, the other structures and preparation process of the reflective wavelength conversion device are basically the same as those of Example 1, and will not be repeated here.

[0055] Example 3 The reflective wavelength conversion device of this embodiment includes a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence.

[0056] The laser diffusion layer is mainly composed of a first package and functional phase particles dispersed in the first package. The mass ratio of the functional phase particles to the first package is 2.2:10, and the thickness of the laser diffusion layer is 30μm. The functional phase particles are aluminum oxide particles, including coarse particles with a median diameter of D50 = 0.1μm and fine particles with a median diameter of D50 = 0.01μm. The mass ratio of coarse particles to fine particles is 1.2:1. The first package uses glass powder with a refractive index of less than 1.6 and a full melting temperature of about 700℃.

[0057] The wavelength conversion layer is the same as that in Example 1.

[0058] The fluorescent reflecting layer is the same as that in Example 1.

[0059] The heat sink substrate is the same as that in Example 1.

[0060] Except for the thickness of the laser diffusion layer and the amount of each raw material, the other structures and preparation process of the reflective wavelength conversion device are basically the same as those of Example 1, and will not be repeated here.

[0061] Example 4 The reflective wavelength conversion device of this embodiment includes a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence.

[0062] The laser diffusion layer is mainly composed of a first package and functional phase particles dispersed in the first package. The mass ratio of the functional phase particles to the first package is 4:10, and the thickness of the laser diffusion layer is 8μm. The functional phase particles are aluminum oxide particles, including coarse particles with a median diameter of D50 = 0.3μm and fine particles with a median diameter of D50 = 0.03μm. The mass ratio of coarse particles to fine particles is 0.4:1. The first package uses glass powder with a refractive index of less than 1.6 and a full melting temperature of about 700℃.

[0063] The wavelength conversion layer is the same as that in Example 1.

[0064] The fluorescent reflecting layer is the same as that in Example 1.

[0065] The heat sink substrate is the same as that in Example 1.

[0066] Except for the thickness of the laser diffusion layer and the amount of each raw material, the other structures and preparation process of the reflective wavelength conversion device are basically the same as those of Example 1, and will not be repeated here.

[0067] Example 5 The reflective wavelength conversion device of this embodiment includes a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence.

[0068] The laser diffusion layer is the same as that in Example 1.

[0069] The wavelength conversion layer is mainly composed of the second package body and the phosphor particles and scattering particles dispersed in the second package body. The mass ratio of scattering particles to phosphor particles is 10:100, and the mass ratio of phosphor particles to the second package body is 10:1. The thickness of the wavelength conversion layer is 40μm. The phosphor particles are α-Sialon:Eu yellow powder particles with a particle size of 10μm, the scattering particles are aluminum oxide particles with a particle size of 0.1μm, and the second package body is made of glass powder. The full melting temperature is about 750℃.

[0070] The fluorescent reflection layer is a sintered silver reflection layer with a thickness of 10 μm. The sintered silver reflection layer is the same as that of Example 1 except for the thickness.

[0071] The heat sink substrate adopts a single crystal silicon substrate with a thickness of 0.5 mm and at least one side is finely ground, and the surface roughness of the finely ground surface Ra≤5μm.

[0072] Except for the raw material dosage of the wavelength conversion layer, the thickness of the fluorescent reflection layer, and the heat sink substrate, the other structures and preparation processes of this embodiment 5 are basically the same as those of embodiment 1, and will not be repeated here.

[0073] Example 6 The reflective wavelength conversion device of this embodiment includes a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence.

[0074] The laser diffusion layer is the same as that in Example 1.

[0075] The wavelength conversion layer is mainly composed of the second package body and the phosphor particles and scattering particles dispersed in the second package body. The mass ratio of scattering particles to phosphor particles is 25:100, the mass ratio of phosphor particles to the second package body is 2:1, and the thickness of the wavelength conversion layer is 120μm. The phosphor particles are α-Sialon:Eu yellow powder particles with a particle size of 10μm, the scattering particles are aluminum oxide particles with a particle size of 0.1μm, and the second package body is made of glass powder, with a full melting temperature of about 750℃.

[0076] The fluorescent reflection layer is a sintered silver reflection layer with a thickness of 30 μm. The sintered silver reflection layer is the same as that of Example 1 except for the thickness.

[0077] The heat sink substrate adopts a single crystal silicon substrate with a thickness of 3 mm and at least one side is finely ground, and the surface roughness of the finely ground surface Ra is less than or equal to 0.02 μm.

[0078] Except for the raw material dosage of the wavelength conversion layer, the thickness of the fluorescent reflection layer, and the heat sink substrate, the other structures and preparation processes of this embodiment 6 are basically the same as those of embodiment 1, and will not be repeated here.

[0079] Example 7 The reflective wavelength conversion device of this embodiment includes a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence.

[0080] The laser diffusion layer is mainly composed of a first package and functional phase particles dispersed in the first package. The mass ratio of the functional phase particles to the first package is 2.8:10, and the thickness of the laser diffusion layer is 20μm. The functional phase particles are titanium oxide particles, including coarse particles with a median diameter of D50 = 0.2μm and fine particles with a median diameter of D50 = 0.02μm. The mass ratio of coarse particles to fine particles is 0.8:1. The first package uses glass powder with a refractive index of less than 1.6 and a full melting temperature of about 700℃.

[0081] The wavelength conversion layer is mainly composed of a second package body and phosphor particles and scattering particles dispersed in the second package body. The mass ratio of scattering particles to phosphor particles is 15:100, the mass ratio of phosphor particles to the second package body is 5:1, and the thickness of the wavelength conversion layer is 80μm. The phosphor particles are α-Sialon:Eu yellow powder particles with a particle size of 20μm, the scattering particles are magnesium oxide particles with a particle size of 0.3μm, and the second package body is organic siloxane.

[0082] The fluorescent reflection layer adopts a dielectric film reflection layer, specifically a stacked structure of tantalum oxide and silicon oxide, with a thickness of 5 μm.

[0083] The heat sink substrate adopts a single crystal silicon substrate with a thickness of 1 mm and at least one side is polished, and the surface roughness of the polished surface Ra≤0.02 μm.

[0084] The reflective wavelength conversion device is prepared according to the following steps: (1) A dielectric film reflective layer is coated on the surface of the heat sink substrate: A dielectric film reflective layer is attached to the surface of the heat sink substrate by evaporation. By controlling the coating power and time, a dielectric film reflective layer of a preset thickness is obtained.

[0085] (2) Prepare wavelength conversion layer slurry: Add phosphor particles, second encapsulation body and scattering particles into a mortar according to the set ratio, add 25wt% of pine oil to the total powder, grind manually for 30 minutes and stir evenly, then transfer the mixed slurry to a planetary stirring device and continue stirring to remove bubbles until the powder particles in the mixed slurry are evenly dispersed to obtain wavelength conversion layer slurry.

[0086] (3) The side of the heat sink substrate covered with a dielectric film reflective layer is covered with a wavelength conversion layer: the wavelength conversion layer slurry is coated on the side of the heat sink substrate covered with a dielectric film reflective layer by using a screen printing process, and a wavelength conversion layer wet film of a preset thickness is obtained by controlling the screen parameters and printing process parameters; then, the wet film is baked in a baking oven at a temperature of 100-130°C for 30-60 minutes to volatilize the pine oil in the wet film of the wavelength conversion layer; finally, the wet film is sintered in a sintering furnace at 800-900°C for 30-120 minutes to melt the second packaging body in the wavelength conversion layer, so that the wavelength conversion layer is firmly bonded to the surface of the heat sink substrate.

[0087] (4) Preparation of laser diffusion layer slurry: According to the designed ratio, the coarse particles, fine particles and the first encapsulation of the functional phase particles are added to the grinding device, and 45 wt% of the total powder amount of pine oil is added. The mixture is manually ground for 30 min and stirred evenly. The mixed slurry is then transferred to a planetary stirring device and continued to be stirred to remove bubbles until the powder particles in the mixed slurry are evenly dispersed to obtain the laser diffusion layer slurry.

[0088] (5) The wavelength conversion layer-covered side of the heat sink substrate is covered with a laser diffusion layer: a screen printing process is used to coat the laser diffusion layer slurry on the wavelength conversion layer-covered side of the heat sink substrate, and a laser diffusion layer wet film of a preset thickness is obtained by controlling the screen parameters and the printing process parameters; then, the laser diffusion layer is baked in a baking oven at a temperature of 100 to 130°C for 30 to 60 minutes to volatilize the pine oil inside the laser diffusion layer wet film, thereby obtaining a laser diffusion layer dry film; finally, the laser diffusion layer is sintered in a sintering furnace at a temperature of 700 to 800°C for 30 to 120 minutes to melt the first packaging body inside the laser diffusion layer, so that the laser diffusion layer is firmly bonded to the surface of the heat sink substrate, thereby obtaining the reflective wavelength conversion device.

[0089] Comparative Example 1 The reflective wavelength conversion device of this comparative example 1 comprises a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence. Except that the functional phase particles of the laser diffusion layer do not contain fine particles, the other parts are the same as those of the embodiment 1.

[0090] Comparative Example 2 The reflective wavelength conversion device of this comparative example comprises a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence. Except that the functional phase particles of the laser diffusion layer do not contain coarse particles, the other parts are the same as those of Example 1.

[0091] Comparative Example 3 The reflective wavelength conversion device of this comparative example comprises a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence. Except that the median diameter D50 of the fine particles in the functional phase particles of the laser diffusion layer is 0.08 μm, the rest is the same as in Example 1.

[0092] Comparative Example 4 The reflective wavelength conversion device of this comparative example comprises a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence. Except that the median diameter D50 of the fine particles in the functional phase particles of the laser diffusion layer is 0.005 μm, the rest is the same as in Example 1.

[0093] Comparative Example 5 The reflective wavelength conversion device of this comparative example comprises a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence. Except that the median diameter D50 of the coarse particles in the functional phase particles of the laser diffusion layer is 0.05 μm, the rest is the same as in Example 1.

[0094] Comparative Example 6 The reflective wavelength conversion device of this comparative example comprises a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence. Except that the median diameter D50 of the coarse particles in the functional phase particles of the laser diffusion layer is 0.8 μm, the rest is the same as in Example 1.

[0095] Comparative Example 7 The reflective wavelength conversion device of this comparative example comprises a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate stacked in sequence. Except that the mass ratio of coarse particles to fine particles in the laser diffusion layer functional phase particles is 0.2:1, the rest is the same as in Example 1.

[0096] Comparative Example 8 The reflective wavelength conversion device of this comparative example comprises a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate stacked in sequence. Except that the mass ratio of coarse particles to fine particles in the laser diffusion layer functional phase particles is 1.5:1, the rest is the same as in Example 1.

[0097] The reflective wavelength conversion devices prepared in the above embodiments and comparative examples were assembled on a laser light source system with a maximum laser power of 60w, 3A current, an electric laser power of 55w, and a Gaussian spot size of Φ1mm in diameter, and tested with a 130mm lens. The test items and test methods are as follows: (1) Illuminance and color temperature test: Light up the light source so that the light beam is projected onto a white wall. Use a illuminance meter to test the central illuminance and color temperature of the wall above the wavelength conversion device.

[0098] (2) Beam quality test: Record the light beam effects of the light sources assembled with the above-mentioned different reflective wavelength conversion devices, and judge the color difference between the center and edge of the light beam.

[0099] The test results are shown in Table 1.

[0100] Table 1 Test results of embodiments and comparative examples

[0101] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A reflective wavelength conversion device, characterized in that: The reflective wavelength conversion device includes a laser diffusion layer, a wavelength conversion layer, a fluorescent reflection layer and a heat sink substrate which are stacked in sequence. The laser diffusion layer includes a first package and functional phase particles dispersed in the first package. The mass ratio of the functional phase particles to the first package is (1.5-4):

10. The visible light transmittance of the first package is above 90%. The functional phase particles include coarse particles and fine particles. The mass ratio of the coarse particles to the fine particles is (0.4-1.2):

1. The median diameter D50 of the coarse particles is 0.1-0.4 μm, and the median diameter D50 of the fine particles is 0.01-0.05 μm. The laser diffusion layer is used to scatter the incident laser and make part of the laser continue to travel along the incident direction, while the other part of the laser travels in the direction opposite to the incident direction.

2. The reflective wavelength conversion device according to claim 1, characterized in that: The wavelength conversion layer includes a second package and phosphor particles dispersed in the second package, the mass ratio of the phosphor particles to the second package is (2-10):1, the visible light transmittance of the second package is above 90%, and the particle size of the phosphor particles is 10-20 μm.

3. The reflective wavelength conversion device according to claim 2, characterized in that: The wavelength conversion layer further includes scattering particles dispersed in the second encapsulation body, the mass ratio of the scattering particles to the phosphor particles is (1-25):100, and the particle size of the scattering particles is 0.01-0.3 μm.

4. The reflective wavelength conversion device according to claim 3, characterized in that: The material of the first packaging body is selected from any one of organic silica gel, inorganic siloxane, and glass powder; and / or The material of the functional phase particles is at least one selected from aluminum oxide, zinc oxide, magnesium oxide, titanium oxide, and lithopone; and / or The material of the second packaging body is selected from any one of organic silica gel, inorganic siloxane and glass powder; and / or The material of the phosphor particles is selected from at least one of yellow powder, green powder and red powder; and / or The material of the scattering particles is at least one selected from titanium oxide, aluminum oxide, magnesium oxide, zinc oxide, zirconium oxide, tantalum oxide, lithopone, and barium sulfate powder.

5. The reflective wavelength conversion device according to claim 4, characterized in that: The material of the first package body is glass powder with a refractive index of less than 1.6 and a full melting temperature of 550~750℃, and the material of the second package body is glass powder with a refractive index of less than 1.6 and a full melting temperature of 650~850℃. The full melting temperature of the glass powder used in the first package body is lower than the full melting temperature of the glass powder used in the second package body.

6. The reflective wavelength conversion device according to any one of claims 1 to 5, characterized in that: The fluorescent reflection layer is selected from any one of a metal reflection layer and a dielectric film reflection layer, the material of the metal reflection layer is selected from any one of silver, aluminum, and aluminum-silver alloy, and the material of the dielectric film reflection layer is selected from a stacked structure of tantalum oxide and silicon oxide or a stacked structure of titanium oxide and silicon oxide.

7. The reflective wavelength conversion device according to any one of claims 1 to 5, characterized in that: The room temperature thermal conductivity of the heat sink substrate exceeds 30w / (m·k), and the heat sink substrate is selected from any one of a ceramic substrate and an inorganic substrate, the ceramic substrate is selected from an aluminum nitride substrate, a silicon carbide substrate, a silicon nitride substrate, and a sapphire substrate, and the inorganic substrate is selected from any one of a single crystal silicon substrate, a polycrystalline or single crystal diamond substrate.

8. The reflective wavelength conversion device according to any one of claims 1 to 5, characterized in that: The thickness of the laser diffusion layer is 5~40μm, the thickness of the wavelength conversion layer is 30~120μm, and the thickness of the heat sink substrate is 0.5~3mm; the fluorescent reflection layer is a sintered metal reflection layer, and the thickness of the sintered metal reflection layer is 10~30μm, or the fluorescent reflection layer is a metal-plated reflection layer, and the thickness of the metal-plated reflection layer is 100~1000nm, or the fluorescent reflection layer is a dielectric film reflection layer, and the thickness of the dielectric film reflection layer is 5~8μm.

9. The reflective wavelength conversion device according to claim 8, characterized in that: The thickness of the laser diffusion layer is 8-30 μm, and the thickness of the wavelength conversion layer is 40-120 μm.

10. A method for preparing a reflective wavelength conversion device according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: (1) A dielectric film reflective layer is coated on the surface of the heat sink substrate: a dielectric film reflective layer is attached to the surface of the heat sink substrate by evaporation; (2) Preparing wavelength conversion layer slurry: adding phosphor particles and the second encapsulation body to a grinding device, adding an organic solvent, stirring evenly, and then transferring the mixed slurry to a stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining a wavelength conversion layer slurry; (4) Preparing laser diffusion layer slurry: according to the designed ratio, the coarse particles, fine particles and the first encapsulation body of the functional phase particles are added to the grinding device, and the organic solvent is added and stirred evenly. Then, the mixed slurry is transferred to the stirring device and continued to be stirred and debubbled until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining the laser diffusion layer slurry; (5) The side of the heat sink substrate covered with the wavelength conversion layer is covered with a laser diffusion layer: a laser diffusion layer slurry is coated on the side of the heat sink substrate covered with the wavelength conversion layer by a screen printing process to obtain a wet film of the laser diffusion layer; then, the film is baked in a baking oven at a temperature of 100 to 130°C for 30 to 60 minutes to obtain a dry film of the laser diffusion layer; finally, the film is sintered in a sintering furnace at a temperature of 700 to 800°C for 30 to 120 minutes to ensure that the laser diffusion layer is firmly bonded to the surface of the heat sink substrate, thereby obtaining the reflective wavelength conversion device; Or, the preparation method comprises the following steps: (1) Preparing metal reflective layer slurry: adding metal powder and glass powder into a grinding device, then adding an organic solvent, stirring evenly, then transferring the mixed slurry to a stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining a metal reflective layer slurry; (2) Covering the surface of the heat sink substrate with a sintered metal reflective layer: Using a steel screen printing process, a layer of metal reflective layer slurry is coated on the surface of the heat sink substrate to obtain a sintered metal reflective layer wet film; then, it is baked in a baking oven at a temperature of 100~130℃ for 30~60min to obtain a sintered metal reflective layer dry film; finally, it is sintered in a sintering furnace at 850~900℃ for 30~60min to ensure that the sintered metal reflective layer is firmly bonded to the surface of the heat sink substrate; (3) Preparing wavelength conversion layer slurry: adding phosphor particles and the second encapsulation body to a grinding device, adding an organic solvent, stirring evenly, and then transferring the mixed slurry to a stirring device to continue stirring and removing bubbles until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining a wavelength conversion layer slurry; (4) The side of the heat sink substrate covered with the sintered metal reflective layer is covered with a wavelength conversion layer: the wavelength conversion layer slurry is coated on the side of the heat sink substrate covered with the sintered metal reflective layer by a screen printing process to obtain a wavelength conversion layer wet film; then, the wavelength conversion layer is baked in a baking oven at a temperature of 100-130°C for 30-60 minutes to obtain a wavelength conversion layer dry film; finally, the wavelength conversion layer is sintered in a sintering furnace at 800-850°C for 30-120 minutes to ensure that the wavelength conversion layer is firmly bonded to the surface of the heat sink substrate; (5) Preparing laser diffusion layer slurry: according to the designed ratio, the coarse particles, fine particles and the first encapsulation body of the functional phase particles are added to the grinding device, and the organic solvent is added and stirred evenly. Then, the mixed slurry is transferred to the stirring device and continued to be stirred and debubbled until the powder particles in the mixed slurry are evenly dispersed, thereby obtaining the laser diffusion layer slurry; (6) The wavelength conversion layer-covered side of the heat sink substrate is covered with a laser diffusion layer: the laser diffusion layer slurry is coated on the wavelength conversion layer-covered side of the heat sink substrate by screen printing to obtain a wet film of the laser diffusion layer; then, the laser diffusion layer is baked in a baking oven at a temperature of 100 to 130°C for 30 to 60 minutes to obtain a dry film of the laser diffusion layer; finally, the laser diffusion layer is sintered in a sintering furnace at a temperature of 700 to 800°C for 30 to 120 minutes to ensure that the laser diffusion layer is firmly bonded to the surface of the heat sink substrate, thereby obtaining the reflective wavelength conversion device of this case.

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