Inorganic fluorescence conversion element for laser illumination and display as well as preparation and application of inorganic fluorescence conversion element

Abstract

The invention belongs to the technical field of laser illumination and laser display, and discloses an inorganic fluorescence conversion element for laser illumination and display and preparation and application thereof, the inorganic fluorescence conversion element comprises a fluorescent glass layer (1), a Ti / Cu seed layer (3), a composite coating (2) and a heat dissipation substrate (4); wherein the upper surface of the heat dissipation substrate (4) is covered by the fluorescent glass layer (1), and the side surfaces and the upper surface of the heat dissipation substrate (4) are coated by the Ti / Cu seed layer (3); the Ti / Cu seed layer (3) is of a laminated structure of a Ti layer and a Cu layer; and the composite plating layer (2) is a metal copper electroplated layer doped with nano and / or micron-sized heat-conducting particles (22). According to the invention, the heat dissipation performance of the fluorescent glass layer is improved by using the fully-coated heat conduction structure of the composite coating, and meanwhile, the Ti layer in the seed layer also improves the back extraction of photons, so that the luminance of a laser light source (especially a white laser light source) is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser lighting and laser display, and more specifically, relates to an inorganic fluorescence conversion element for laser lighting and display, and its preparation and application. Background Art

[0002] Laser lighting technology has the advantages of ultra-high power (such as, above 30 W / mm 2 above), ultra-high brightness (such as, above 5000 lumens), high collimation, long irradiation distance, and higher conversion efficiency under high current density, etc., and gradually replaces traditional light sources and is widely used in fields such as automotive headlights, aviation lighting, medical and health, special lighting, visible light communication, etc. Laser display technology is also the mainstream technology for future high-end displays such as large-screen projection, automotive flat panel displays, digital cinemas, and mobile phone projections.

[0003] Currently, in the technical solutions of laser lighting and laser backlight display, a fluorescence conversion white laser light source is often adopted, that is, a blue laser chip remotely excites a yellow phosphor layer, including a transmissive laser light source and a reflective laser light source. Since the irradiation spot of the blue laser chip is small and the laser power density is high, the phosphor layer needs to withstand high laser radiation energy and fluorescence conversion heat, while traditional organic fluorescent resins have poor heat resistance and low thermal conductivity, and there are some problems of thermal corrosion and carbonization under high-power density laser excitation, making it difficult to meet the packaging requirements of white laser light sources. Therefore, conversion materials based on fluorescent glass have gradually become the research focus.

[0004] Fluorescent glass is an inorganic composite material composed of glass and phosphor, and has the advantages of high thermal stability, easy adjustment of optical properties, simple preparation process, low cost, etc. However, due to the low thermal conductivity of the fluorescent glass layer, traditional single-sided heat dissipation structures such as ceramic-based and sapphire-based are prone to thermal deposition failure on the outer surface far from the heat dissipation substrate under high-power laser excitation, which has a great impact on the luminous brightness and thermal stability of white laser light sources (for example, in the prior art, Cu sheets have been used to form fluorescent glass through medium and low temperature co-firing, but under the high-temperature conditions of lasers, due to the difference in thermal expansion coefficients, the fluorescent glass will be damaged); at the same time, the reflective fluorescence conversion element has a serious light absorption effect, making it difficult to meet the requirements of laser driving or excitation, restricting the development of laser lighting technology. Therefore, it is urgent to propose an inorganic fluorescence conversion element with a high luminous saturation threshold (greater than 30 W / mm 2 ) and high light extraction (luminous efficiency greater than 200 lm / W) to meet the requirements of high-power laser lighting and laser display. Summary of the Invention

[0005] In view of the above defects or improvement requirements of the prior art, the purpose of the present invention is to provide an inorganic fluorescence conversion element for laser lighting and display, its preparation and application. The all-round heat-conducting structure of the composite coating improves the heat dissipation performance of the fluorescent glass layer. At the same time, the Ti layer in the seed layer also improves the back extraction of photons, effectively improving the luminous brightness of the laser light source (especially the white laser light source). No organic bonding material is used in the inorganic fluorescence conversion element of the present invention, avoiding the failure or even carbonization of organic materials under high-power laser excitation and high temperature, improving the long-term reliability of the inorganic fluorescence conversion element, and being able to solve the problem of failure of the traditional single-sided heat dissipation structure under high-power laser excitation.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided a reflective inorganic fluorescence conversion element for laser lighting or laser display, including a fluorescent glass layer, a Ti / Cu seed layer, a composite coating and a heat dissipation substrate; wherein, Part or all of the upper surface of the heat dissipation substrate is covered by the fluorescent glass layer, and the two are closely connected; when part of the upper surface of the heat dissipation substrate is covered by the fluorescent glass layer, the side surface and the upper surface of the fluorescent glass layer, the side surface of the heat dissipation substrate and the upper surface not covered by the fluorescent glass layer are all coated with the Ti / Cu seed layer; when all of the upper surface of the heat dissipation substrate is covered by the fluorescent glass layer, the side surface and the upper surface of the fluorescent glass layer, and the side surface of the heat dissipation substrate are all coated with the Ti / Cu seed layer; The upper surface and the side surface of the Ti / Cu seed layer are completely covered by the composite coating; the Ti / Cu seed layer is a laminated structure of a Ti layer and a Cu layer, wherein the Cu layer is in direct contact with the composite coating; the composite coating is a copper electroplating layer doped with nano- and / or micron-sized heat-conducting particles.

[0007] As a further preference of the present invention, the heat dissipation substrate has a transmittance of not less than 60% in the wavelength range of 430-480 nm, and the material of the heat dissipation substrate is transparent sapphire or diamond.

[0008] As a further preference of the present invention, the overall reflectance of the composite coating is not less than 90% in the wavelength range of 430-480 nm.

[0009] As a further preference of the present invention, the thickness of the fluorescent glass layer is 60-200 μm; The thickness of the Ti / Cu seed layer is 100-200 nm; The thickness of the composite coating is 100-250 μm.

[0010] As a further preference of the present invention, the material used for the heat-conducting particles has a thermal conductivity greater than 30 W / (m·K); In the composite coating, the volume ratio of the heat-conducting particles is 10% - 50%.

[0011] As a further preference of the present invention, the material of the heat-conducting particles is one or more of diamond, boron nitride or alumina.

[0012] According to another aspect of the present invention, the present invention provides a method for preparing the above-mentioned inorganic fluorescence conversion element for reflective laser illumination or laser display, comprising the following steps: S1. Prepare a fluorescent glass paste, coat the fluorescent glass paste on the heat dissipation substrate to form a fluorescent glass paste layer, and then co-fire to complete the melting of the glass, so as to form a fluorescent glass layer covering a part of the upper surface of the heat dissipation substrate; S2. Through a magnetron sputtering process, deposit a Ti layer and a Cu layer on the side surface and the upper surface of the fluorescent glass layer, the side surface of the heat dissipation substrate and the upper surface not covered by the fluorescent glass layer to obtain a Ti / Cu seed layer; S3. Use a copper electroplating solution doped with nano- and / or micron-scale heat-conducting particles, and prepare a composite coating on the upper surface and the side surface of the Ti / Cu seed layer through an electroplating process, so as to obtain an inorganic fluorescence conversion element for reflective laser illumination or laser display.

[0013] As a further preference of the present invention, in step S1, the coating is carried out by screen printing; The fluorescent glass paste is mixed from raw materials including phosphor powder, glass powder and organic solvent; The phosphor powder is a monochromatic phosphor powder or a multicolor phosphor powder; The mass ratio of the phosphor powder to the glass powder is (0.3 - 2):1; The glass powder is a low-temperature glass powder with a glass transition temperature not exceeding 700 °C; The temperature used for the co-firing is 550 - 700 °C; the sintering time is 40 - 90 min.

[0014] According to still another aspect of the present invention, the present invention provides the application of the above-mentioned inorganic fluorescence conversion element for reflective laser illumination or laser display, which is used for laser illumination or laser display, with a luminous flux of more than 5000 lm and a laser power density of 30 W / mm 2 or more.

[0015] As a further preference of the present invention, the laser illumination and the laser display are used for a fluorescence conversion white laser light source.

[0016] Through the above technical solutions conceived by the present invention, compared with the prior art, the following beneficial effects can be achieved: (1) The inorganic fluorescence conversion element obtained in the present invention has a reflective structure, and the all-round heat dissipation of the fluorescence conversion element is realized through a composite coating and a heat dissipation substrate. When the inorganic fluorescence conversion element obtained in the present invention is in use, the laser is incident from below the heat dissipation substrate. After traveling to the fluorescent glass layer, when it encounters phosphor particles, fluorescence will be excited. At the same time, when the light encounters the Ti layer in the seed layer, reflection will occur. Therefore, it is a reflective structure. In the field of lasers, the prior art has already used Cu sheets to form fluorescent glass through medium and low temperature co-firing. However, due to the difference in thermal expansion coefficient, under the condition of high-power laser excitation, the local temperature will rise rapidly, and the fluorescent glass will be damaged. Moreover, the electroplating process is rarely used in the laser field. In the present invention, a composite Cu layer is electroplated on the heat dissipation substrate-fluorescent glass sheet, and all-round heat dissipation is realized through the upper composite Cu layer and the lower heat dissipation substrate. The composite coating can achieve heat conduction above and on the side of the fluorescent glass layer, improving reliability. At the same time, the Ti layer in the seed layer can also improve the light efficiency (this is because the Cu layer has serious photon absorption, while the Ti layer in the seed layer has a reflection effect and can be used for light extraction on the back of the fluorescent glass layer), and the heat dissipation substrate can also achieve heat conduction below the fluorescent glass layer.

[0017] (2) The reflective inorganic fluorescence conversion element obtained in the present invention is an inorganic fluorescence conversion element with a high luminous saturation threshold (greater than 30 W / mm 2 ), and high light extraction (luminous efficiency greater than 200 lm / W). It can be applied to a high laser saturation threshold fluorescence conversion white laser light source and can meet the requirements of high-power laser lighting and laser display. The inorganic fluorescence conversion element in the present invention can be applied to a high-brightness fluorescence conversion white laser light source and can withstand high-power density laser driving or excitation, enabling the white laser light engine and its equipment to have ultra-high brightness and reliability, and promoting the development of laser lighting technology.

[0018] (3) The composite coating of the reflective inorganic fluorescence conversion element obtained in the present invention is doped with micron-sized heat-conducting particles, which improves the overall thermal conductivity of the fluorescence conversion element while effectively alleviating the problem of excessive internal stress and cracking in the electroplated metal layer during micron-sized thick film electroplating, optimizing the problem of insufficient heat conduction of the fluorescent glass layer, and ensuring the reliability of the element during long-term operation under high laser power input. Brief Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of an inorganic fluorescence conversion element for laser lighting and display provided by an embodiment of the present invention.

[0020] Figure 2 It is an enlarged schematic structural diagram of the composite coating in an embodiment of the present invention.

[0021] Figure 3Process flow chart for preparing an inorganic fluorescence conversion element for laser illumination and display provided by an embodiment of the present invention.

[0022] Figure 1 , Figure 2 In the figures, the meanings of the respective reference numerals are as follows: 1 is a fluorescent glass layer, 2 is a composite coating layer, 3 is a Ti / Cu seed layer, 4 is a heat dissipation substrate, 21 is a copper matrix, and 22 is a heat conduction particle. Detailed implementation manners

[0023] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various implementation manners of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] Embodiment 1 An inorganic fluorescence conversion element for laser illumination and laser display, as Figure 1 shown, includes: a fluorescent glass layer 1, a composite coating layer 2, a Ti / Cu seed layer 3, and a heat dissipation substrate 4; wherein, the fluorescent glass layer 1 is located on the upper surface of the heat dissipation substrate 4, the Ti / Cu seed layer 3 is located on the upper surface and side surfaces of the heat dissipation substrate 4 and the fluorescent glass layer 1, and the composite coating layer 2 is disposed above and on the side surfaces of the Ti / Cu seed layer 3 (completely covering the Ti / Cu seed layer 3; wherein, the Ti / Cu seed layer 3 is a stacked structure of a Ti layer and a Cu layer, the Ti layer is in direct contact with the fluorescent glass layer 1, and the Cu layer is in direct contact with the composite coating layer 2); the heat dissipation substrate 4 has a transmittance greater than 60% in the wavelength band of 430 - 480 nm; the composite coating layer 2 has a reflectance greater than 90% in the wavelength band of 430 - 480 nm; this inorganic fluorescence conversion element is a reflective structure, and high-power blue light (such as, power 3W; of course, other power settings above 3W can also be used) is excited from one side of the heat dissipation substrate to excite yellow phosphor to obtain white light for laser illumination or display.

[0025] The preparation method of this inorganic fluorescence conversion element, as Figure 3 shown, mainly includes the following steps: Step 1: Preparation of phosphor. Select a sapphire substrate with a thickness of 1 mm; the length and width of the sapphire substrate are both 15 mm; mix 0.5 g of YAG phosphor with 1.5 g of Schott glass powder (chemical composition: 25B2O3-10SiO2-35ZnO-6Li2O-12La2O3-12WO3; the Arabic numerals before each component in the chemical composition represent the molar percentage of that component. Taking 25B2O3 as an example, the molar percentage of B2O3 in the glass powder is 25%; the same below), and 0.35 g of turpentine alcohol to form a fluorescent glass paste, and coat it on the surface of the 1-mm-thick sapphire heat dissipation substrate through the screen printing process; the area of the fluorescent glass layer is 20 mm 2 (Of course, other area settings can also be adopted, as long as part or all of the upper surface of the heat dissipation substrate is covered by the fluorescent glass layer; for example, other areas within the range of 20~40 mm 2 ). Then sinter at 700 °C (sintering time is 90 min) to obtain a fluorescent glass film with a thickness of 0.1 mm.

[0026] Step 2: Prepare a seed layer on the upper surface of the fluorescent glass layer and the side surface of the sapphire by magnetron sputtering. The materials are Ti metal and Cu metal (the targets are titanium target and copper target with a purity of 99.999%), which are used for the light extraction of the fluorescent glass layer facing away from the light. The process parameters of magnetron sputtering are: vacuum degree is 3.0×10 −4 Pa, the substrate temperature is 25 °C, the target-substrate distance is 6 cm, the DC power supply power is 1500 W, the argon gas flow rate is 30 mL / min, the sputtering pressure is 0.5 Pa, and the sputtering time is 100 s (sputter the Ti target first, and then the Cu target; among them, the sputtering time of the Ti target is 50 s, and the sputtering time of the Cu target is 50 s). The thickness of the obtained seed layer is 100 nm, among which, the thickness of the Ti layer is 50 nm, and the thickness of the Cu layer is 50 nm.

[0027] Step 3: Electroplate copper on the outer surface of the seed layer. The working temperature of electroplating additive is 25 °C; the current density is 6.5 A / cm 2 ; the electroplating rate is 100 μm / h, and the components of the electroplating solution used are: 187.5 g / L of copper sulfate pentahydrate, 60 g / L of sulfuric acid, 50 mg / L of sodium chloride, 300 mg / L of polyethylene glycol, 6 mg / L of sodium thiazolinyl dithiopropane sulfonate, and the stirring rate is 400 revolutions per minute. The electroplating solution is doped with diamond micropowder with a particle size of 100 microns and a doping amount of 50 g / L.

[0028] Comparative Example 1 The preparation process of Comparative Example 1 is generally the same as that of Example 1, except that in Step 3, no heat-conducting particles are added to the electroplating solution; accordingly, the obtained electroplated copper layer will crack due to excessive internal stress, and a device with the desired structure cannot be obtained.

[0029] Comparative Example 2 This Comparative Example 2 is to prepare a traditional sapphire-based fluorescence conversion element. The preparation method only includes Step 1 of Example 1 (all parameter conditions in Step 1 are the same as those in Step 1 of Example 1), and Steps 2 and 3 are not carried out.

[0030] Example 2 An inorganic fluorescence conversion element for laser illumination and display, as Figure 1 shown, includes: a fluorescent glass layer 1, a composite coating layer 2, a Ti / Cu seed layer 3, and a heat dissipation substrate 4; wherein, the fluorescent glass layer 1 is located on the upper surface of the heat dissipation substrate 4, the Ti / Cu seed layer 3 is located on the upper surface and side surfaces of the heat dissipation substrate 4 and the fluorescent glass layer 1, and the composite coating layer 2 is disposed above and on the side of the Ti / Cu seed layer 3 (completely covering the Ti / Cu seed layer 3; wherein, the Ti / Cu seed layer 3 is a laminated structure of a Ti layer and a Cu layer, the Ti layer is in direct contact with the fluorescent glass layer 1, and the Cu layer is in direct contact with the composite coating layer 2); the heat dissipation substrate 4 has a transmittance greater than 70% in the wavelength band of 430 - 480 nm; the composite coating layer 2 has a reflectivity greater than 90% in the wavelength band of 430 - 480 nm; this inorganic fluorescence conversion element is a reflection type structure, and high-power blue light (such as, a power of 3 W) excites yellow phosphor from one side of the heat dissipation substrate to obtain white light for laser illumination or display.

[0031] The preparation method of this inorganic fluorescence conversion element, as Figure 3 shown, mainly includes the following steps: Step 1, preparation of the phosphor. Select a sapphire substrate with a thickness of 1.5 mm; select the length and width of the sapphire substrate to be 15 mm each; mix 1 g of YAG phosphor with 0.5 g of low-temperature glass powder (chemical composition: 20Bi2O3 - 60B2O3 - 10ZnO - 10BaO) and 0.32 g of turpentine alcohol to form a fluorescent glass slurry, and coat it on the surface of a 1.5-mm-thick sapphire heat dissipation substrate through a screen printing process; the area of the fluorescent glass layer is 40 mm 2 ; then sinter at 550 °C (sintering time is 40 min) to obtain a fluorescent glass film with a thickness of 0.2 mm.

[0032] Step 2, prepare a seed layer on the upper surface of the fluorescent glass layer and the side surface of the sapphire by a magnetron sputtering process, and the materials are Ti metal and Cu metal (the targets are titanium target and copper target with a purity of 99.999%), which is used for light extraction from the back of the fluorescent glass layer. The process parameters of magnetron sputtering are: the vacuum degree is 3.5×10−4 Pa, the substrate temperature is 30 °C, the target-substrate distance is 6.5 cm, the DC power supply power is 1200 W, the argon gas flow rate is 45 mL / min, the sputtering pressure is 0.5 Pa, and the sputtering time is 200 s (first sputter the Ti target and then the Cu target; among them, the sputtering time of the Ti target is 100 s, and the sputtering time of the Cu target is 100 s). The thickness of the seed layer obtained is 200 nm, among which, the thickness of the Ti layer is 100 nm, and the thickness of the Cu layer is 100 nm.

[0033] Step three, electroplate copper on the outer surface of the seed layer. The working temperature of electroplating additive manufacturing is 25 °C; the current density is 8 A / cm 2 ; the electroplating rate is 100 μm / h, and the composition of the electroplating solution used is: 195.5 g / L of copper sulfate pentahydrate, 75 g / L of sulfuric acid, 45 mg / L of sodium chloride, 300 mg / L of polyethylene glycol, 8.5 mg / L of sodium thiazolinyl disulfide propane sulfonate, and the stirring rate is 500 revolutions per minute. The electroplating solution is doped with diamond micropowder with a particle size of 400 microns and a doping amount of 10 g / L.

[0034] Comparative Example 3 The preparation process of this Comparative Example 3 is generally the same as that of Example 2, except that in step three, no heat-conducting particles are added to the electroplating solution; accordingly, the obtained electroplated copper layer will crack due to excessive internal stress and a device with the desired structure cannot be obtained.

[0035] Comparative Example 4 This Comparative Example 4 is to prepare a traditional sapphire-based fluorescence conversion element. The preparation method only includes step one of Example 2 (the parameter conditions in step one are all the same as those in step one of Example 2), and steps two and three are not passed through.

[0036] For the fully encapsulated heat-dissipating inorganic fluorescence conversion element prepared in Example 1, under 3 W laser irradiation, compared with the traditional sapphire-based fluorescence conversion element prepared in Comparative Example 2, the luminous efficiency is only 186 lm / W, and the luminous efficiency is increased to 214 lm / W. The laser power saturation threshold tolerance is increased from 10 W / mm of the device obtained in Comparative Example 2 2 to 36 W / mm 2 ; the corresponding luminous flux under the saturation threshold is increased from 1836 lm of the device obtained in Comparative Example 2 to 5384 lm. It can be seen that the fully encapsulated heat-dissipating inorganic fluorescence conversion element prepared in Example 1 can meet the requirements of high heat conduction and high light extraction laser illumination applications.

[0037] The fully encapsulated heat-dissipating inorganic fluorescence conversion element prepared in Example 2, under 3 W laser irradiation, compared with the traditional sapphire-based fluorescence conversion element prepared in Comparative Example 4 with a luminous efficacy of only 178 lm / W, the luminous efficacy is increased to 205 lm / W. The laser power saturation threshold tolerance is increased from 17 W / mm of the device obtained in Comparative Example 4 2 to 42 W / mm 2 ; the corresponding luminous flux under the saturation threshold is increased from 2085 lm of the device obtained in Comparative Example 4 to 5983 lm. It can be seen that Example 2 also meets the requirements of high thermal conductivity and high light extraction for laser lighting applications.

[0038] Example 3 The preparation process of this Example 3 is generally the same as that of Example 2, except that in Step 1, the sapphire substrate is replaced with a diamond substrate of the same size. Due to the excellent thermal conductivity of the diamond substrate (>500 W·m -1 ·K -1 ), the prepared fluorescence conversion element has a laser power saturation threshold tolerance increased from 17 W / mm of the device obtained in Comparative Example 4 2 to 58 W / mm 2 ; the corresponding luminous flux under the saturation threshold is increased from 2085 lm of the device obtained in Comparative Example 4 to 7856 lm.

[0039] The above examples are only illustrative. For example, in addition to covering some areas on the upper surface of the heat-dissipating substrate, the fluorescent glass layer can also cover the entire upper surface of the heat-dissipating substrate; for another example, the length, width, and thickness of the heat-dissipating substrate 4 can all be set otherwise (for example, the thickness of the heat-dissipating substrate 4 can also be other thicknesses within the range of 0.3 mm to 3 mm; the overall thickness of the corresponding inorganic fluorescence conversion element can vary from 0.5 mm to 3.5 mm); and, in addition to the sapphire substrate, substrates with good thermal conductivity such as diamond substrates can also be used, as long as the overall heat-dissipating substrate + glass layer has a certain stiffness; the thickness of the Ti layer and the thickness of the Cu layer in the seed layer can also be adjusted separately; the fluorescent glass paste can also adopt other formulations reported in the prior art.

[0040] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An inorganic fluorescence conversion element for reflective laser illumination or laser display, characterized in that, It includes a fluorescent glass layer (1), a Ti / Cu seed layer (3), a composite coating (2), and a heat dissipation substrate (4); wherein, Part or all of the upper surface of the heat dissipation substrate (4) is covered by the fluorescent glass layer (1), and the two are closely connected; when part of the upper surface of the heat dissipation substrate (4) is covered by the fluorescent glass layer (1), the side surface and the upper surface of the fluorescent glass layer (1), the side surface of the heat dissipation substrate (4), and the upper surface not covered by the fluorescent glass layer (1) are all coated with the Ti / Cu seed layer (3); when all of the upper surface of the heat dissipation substrate (4) is covered by the fluorescent glass layer (1), the side surface and the upper surface of the fluorescent glass layer (1), and the side surface of the heat dissipation substrate (4) are all coated with the Ti / Cu seed layer (3); The upper surface and the side surface of the Ti / Cu seed layer (3) are completely covered by the composite coating (2); the Ti / Cu seed layer (3) is a laminated structure of a Ti layer and a Cu layer, wherein the Cu layer is in direct contact with the composite coating (2); the composite coating (2) is a copper electroplating layer doped with nano- and / or micron-sized heat-conducting particles (22).

2. The inorganic fluorescence conversion element for reflective laser illumination or laser display according to claim 1, wherein The transmittance of the heat dissipation substrate (4) in the wavelength range of 430 - 480 nm is not less than 60%, and the material of the heat dissipation substrate (4) is transparent sapphire or diamond.

3. The inorganic fluorescence conversion element for reflective laser illumination or laser display according to claim 1, characterized in that, The overall reflectance of the composite coating (2) in the wavelength range of 430 - 480 nm is not less than 90%.

4. The inorganic fluorescence conversion element for reflective laser illumination or laser display according to claim 1, characterized in that, The thickness of the fluorescent glass layer (1) is 60 - 200 μm; The thickness of the Ti / Cu seed layer (3) is 100 - 200 nm; The thickness of the composite coating (2) is 100 - 250 μm.

5. The inorganic fluorescence conversion element for reflective laser illumination or laser display according to claim 1, characterized in that The material used for the heat-conducting particles (22) has a thermal conductivity greater than 30 W / (m·K); In the composite coating (2), the volume ratio of the heat-conducting particles (22) is 10% - 50%.

6. The inorganic fluorescence conversion element for reflective laser illumination or laser display according to claim 5, characterized in that, The material used for the heat-conducting particles (22) is one or more of diamond, boron nitride, or alumina.

7. The preparation method of the inorganic fluorescence conversion element for reflective laser illumination or laser display according to any one of claims 1-6, characterized in that, It includes the following steps: S1. Prepare a fluorescent glass paste, coat the fluorescent glass paste on the heat dissipation substrate to form a fluorescent glass paste layer, and then co-fire to complete glass melting, thereby covering and forming a fluorescent glass layer on part of the upper surface of the heat dissipation substrate; S2. Through a magnetron sputtering process, deposit a Ti layer and a Cu layer on the side surface and the upper surface of the fluorescent glass layer, the side surface of the heat dissipation substrate, and the upper surface not covered by the fluorescent glass layer to obtain a Ti / Cu seed layer; S3. Use a copper electroplating solution doped with nano- and / or micron-sized heat-conducting particles, and prepare a composite coating on the upper surface and the side surface of the Ti / Cu seed layer through an electroplating process, thereby obtaining an inorganic fluorescent conversion element for reflective laser illumination or laser display.

8. The preparation method according to claim 7, wherein In step S1, the coating is carried out by means of screen printing; The fluorescent glass paste is formed by mixing raw materials including fluorescent powder, glass powder, and organic solvent; The fluorescent powder is a single-color fluorescent powder or a multi-color fluorescent powder; The mass ratio of the fluorescent powder to the glass powder is (0.3 - 2):1; The glass powder is a low-temperature glass powder with a glass transition temperature not exceeding 700 °C; The temperature used for co-firing is 550-700 °C; the sintering time is 40-90 min.

9. Application of the inorganic fluorescence conversion element for reflective laser illumination or laser display according to any one of claims 1 - 6, characterized in that, For laser illumination or laser display, with a luminous flux of more than 5000 lm and a laser power density of 30 W / mm 2 or more.

10. The application according to claim 9, characterized in that, The laser illumination and the laser display are used for a fluorescence-converted white-light laser light source.

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