Wavelength conversion device and preparation method thereof

Abstract

The invention discloses a wavelength conversion device and a preparation method thereof.The wavelength conversion device comprises a heat sink substrate, an active metal transition layer, a high-temperature sintering silver reflecting layer, a glass sintering layer and a wavelength conversion layer which are sequentially stacked from bottom to top, and the high-temperature sintering silver reflecting layer is obtained by sintering glass powder and silver powder; the density of the high-temperature sintering silver reflecting layer is larger than 98%, the coating length and / or width of the high-temperature sintering silver reflecting layer on the heat sink substrate is smaller than the coating length and / or width of the glass sintering layer, the wavelength conversion layer and the active metal transition layer, and the heat sink substrate is a ceramic substrate or an inorganic material substrate with the heat conductivity larger than 30 w / m.k. The wavelength conversion layer is a glass fluorescent layer prepared by sintering inorganic glass powder and fluorescent powder particles or a ceramic fluorescent layer prepared by sintering ceramic powder particles and fluorescent powder particles. The wavelength conversion device is high in limit blue light resistant power, good in heat conduction and heat dissipation effect, high in wavelength conversion efficiency and good in reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of wavelength conversion devices used in laser lighting or laser display fields, and more specifically, to a wavelength conversion device and a preparation method thereof. Background Art

[0002] At present, the color wheel light-emitting devices in the field of laser lighting and laser display mostly use diffuse reflection layers or silver-plated layers as fluorescent reflection layers. The diffuse reflection layer is mainly composed of metal oxide diffuse reflection particles and organic silica gel or inorganic glass powder. The thickness is usually above 70μm or even above 100μm to ensure that the diffuse reflection layer has a high fluorescence reflectivity. However, the thermal conductivity of the diffuse reflection particles, organic silica gel and inorganic glass powder inside the diffuse reflection layer is low, and the reflection layer is thick, resulting in a very low thermal conductivity coefficient of the layer (below 1), which makes the light-emitting device have poor thermal conductivity and heat dissipation effect. The probability of thermal quenching of the fluorescence wavelength conversion layer is high, which affects the reliability of the device's light emission and limits its application in high laser power lighting and display scenarios. The advantage of the wavelength conversion device using a silver-plated reflection layer is that there is no need to design a diffuse reflection layer, the process is simple, and the silver-plated reflection layer also has a high reflectivity in the visible light band. The light-emitting effect of the prepared device can basically match the diffuse reflection layer solution. However, the silver-plated layer in the silver-plated reflective layer is mainly made of aluminum, which can only withstand temperatures below 200°C. The only wavelength conversion material that can be matched for fluorescence generation is the organic fluorescent layer made of organic silica composite fluorescent powder particles. The thermal conductivity of the organic fluorescent layer is very low, which causes the thermal conductivity and heat dissipation of the fluorescent light-emitting device prepared by the silver-plated reflective layer to be poor. The laser power resistance of the device is also not high, which limits its application in high-power display scenarios, such as laser engineering machine light source, laser cinema projector light source, high-power laser searchlight, stage light and beam light, etc. It is necessary to seek a wavelength conversion device with higher resistance to extreme blue light power, better thermal conductivity and heat dissipation. Summary of the invention

[0003] The present invention aims to overcome at least one defect of the above-mentioned prior art and provide a wavelength conversion device, which has high resistance to extreme blue light power, good thermal conductivity and heat dissipation effects, high wavelength conversion efficiency, and good reliability.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A wavelength conversion device comprises a heat sink substrate, an active metal transition layer, a high-temperature sintered silver reflection layer, a glass sintered layer and a wavelength conversion layer which are sequentially stacked from bottom to top, wherein the high-temperature sintered silver reflection layer is obtained by sintering glass powder and silver powder at above 800°C, the density of the high-temperature sintered silver reflection layer is greater than 98%, the coating length and / or width of the high-temperature sintered silver reflection layer on the heat sink substrate is smaller than the coating length and / or width of the glass sintered layer, the wavelength conversion layer and the active metal transition layer, the heat sink substrate is a ceramic substrate or an inorganic material substrate with a thermal conductivity exceeding 30w / m·k, and the wavelength conversion layer is a glass fluorescent layer obtained by sintering inorganic glass powder and fluorescent powder particles, or a ceramic fluorescent layer obtained by sintering ceramic powder particles and fluorescent powder particles.

[0006] This technical solution adopts a ceramic substrate or an inorganic material substrate with a thermal conductivity exceeding 30w / m·k, ensuring that the heat generated during the operation of the wavelength conversion layer can be promptly conducted away through the heat sink substrate, and the substrate can withstand high temperatures above 900°C without damage, thereby ensuring that the high-temperature sintering process of the silver reflective layer will not cause damage to the heat sink substrate.

[0007] Designing an active metal transition layer on the surface of the heat sink substrate can improve the interfacial bonding strength between the heat sink substrate and the high-temperature sintered silver reflective layer. The valence bond of the high-temperature sintered silver reflective layer is mainly a metal bond, while the heat sink substrate is a ceramic or inorganic material, and its valence bond is mainly a covalent bond. The affinity between the metal bond and the covalent bond is poor. The substrate bonding of the two valence bond forms has a weak interfacial bonding strength. Designing an active metal transition layer between the two can improve the bonding strength between the heat sink substrate and the high-temperature sintered silver reflective layer. The reason is that the active metal can form an alloy bond with the silver in the high-temperature sintered silver reflective layer, and can also capture the oxygen in the glass phase component of the high-temperature sintered silver reflective layer to form an oxide covalent bond. In addition, since the material structure of the surface layer of the heat sink substrate usually has defects, it is conducive to the enrichment of oxygen molecules, so an oxide layer is formed on the surface of the heat sink substrate. The oxygen in this oxide layer is easily captured by the highly active metal to form an oxide covalent bond. Under the combined effect of the two, an active metal oxide and alloy transition layer is formed between the heat sink substrate and the high-temperature sintered silver reflective layer, thereby improving the bonding strength between the heat sink substrate and the high-temperature sintered silver reflective layer.

[0008] Compared with the silver-plated reflective layer (the silver-plated reflective layer can only withstand temperatures below 250°C, and can therefore only be adapted to the organic silicone fluorescent light-emitting layer with poor thermal conductivity), the high-temperature sintered silver reflective layer has higher temperature resistance and can be adapted to glass fluorescent layers and ceramic fluorescent layers with high thermal conductivity and good temperature resistance. The wavelength conversion device obtained has higher blue light power resistance. Compared with the diffuse reflection layer and the dielectric film reflection layer, the high-temperature sintered silver reflective layer also has a higher thermal conductivity, and the wavelength conversion device has better thermal conductivity and heat dissipation effects. The better the thermal quenching resistance of the fluorescent layer of the wavelength conversion device obtained, the higher the laser power density resistance. The high-temperature sintered silver reflective layer can be used as a fluorescent reflection part and as a bonding layer between the wavelength conversion layer and the heat sink substrate. There is no need to design an additional bonding layer, which reduces the number of interfaces and thus reduces the interface thermal resistance. The high-temperature sintered silver reflective layer is obtained by sintering glass powder and silver powder at high temperature, and the density is greater than 98%, which can fully guarantee the reflectivity of the high-temperature sintered silver reflective layer and improve the conversion efficiency of the wavelength conversion device. The coating length and / or width of the high-temperature sintered silver reflective layer on the heat sink substrate is smaller than the coating length and / or width of the glass sintered layer, the wavelength conversion layer and the active metal transition layer, thereby ensuring that the high-temperature sintered silver reflective layer is wrapped by the glass sintered layer, the active metal transition layer and the wavelength conversion layer, isolating the high-temperature sintered silver reflective layer from the corrosion effects of water, oxygen and sulfur substances in the air, and improving the reliability of the light-emitting device.

[0009] A glass sintering layer in a glassy state is designed between the high-temperature sintered silver reflective layer and the wavelength conversion layer, which plays the following roles: silver in the high-temperature sintered silver reflective layer is an active metal and is easy to migrate to the wavelength conversion layer, thereby reducing the luminous efficiency of the wavelength conversion layer; the glass sintering layer is a pure glass layer with a dense structure, which can isolate the silver layer from migrating to the wavelength conversion layer, thereby eliminating the influence of the migration of metallic silver on the luminous efficiency of the wavelength conversion layer; the glass sintering layer with a dense structure wraps the high-temperature sintered silver layer, which can isolate the corrosion effects of water vapor, oxygen, sulfur and other substances in the air on the high-temperature sintered silver reflective layer such as oxidation and sulfidation, thereby increasing the reliability and stability of the light-emitting device.

[0010] Compared with the wavelength conversion layer composed of organic silicon or inorganic silicon and phosphor, the glass phosphor layer made by sintering inorganic glass powder and phosphor particles or the ceramic phosphor layer made by sintering ceramic powder particles and phosphor particles has good high temperature resistance and good heat dissipation.

[0011] In one embodiment, the high temperature sintered silver reflective layer is obtained by sintering glass powder and silver powder at 850-900°C.

[0012] In one embodiment, the silver powder includes a first silver powder and a second silver powder, wherein the median diameter of the first silver powder is 0.5-5 μm, and the median diameter of the second silver powder is 20-200 nm. The combination of the two types of silver powders with coarse and fine particles can ensure the density of the high-temperature sintered silver reflective layer and improve the reflectivity of the high-temperature sintered silver reflective layer.

[0013] In one embodiment, the combined specific surface area of ​​the first silver powder and the second silver powder is 1-2 m 2 / g, and the full melting temperature of the glass powder is 700-800° C. Such a combination can make the sintering temperatures of the glass powder and the silver powder compatible.

[0014] In one embodiment, the mass ratio of silver powder to glass powder in the high temperature sintered silver reflective layer is (97-99.5):(0.5-3).

[0015] In one embodiment, the mass ratio of the first silver powder to the second silver powder is (3-8):1, for example, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, etc.

[0016] In one embodiment, the active metal transition layer is a titanium layer, a nickel layer, or a chromium layer.

[0017] In one embodiment, the wavelength conversion layer is a glass fluorescent layer made by sintering inorganic glass powder and fluorescent powder particles, the glass sintered layer is a sintered layer of low-refractive index glass powder, and the low-refractive index glass powder is a powder of inorganic glass powder whose refractive index is not higher than that of the glass fluorescent layer.

[0018] In one embodiment, the sintering temperature of the glass powder in the high-temperature sintered silver reflective layer is greater than the sintering temperature of the low-refractive index glass powder in the glass sintered layer and greater than the sintering temperature of the inorganic glass powder in the wavelength conversion layer.

[0019] In one embodiment, the linear expansion coefficient of the inorganic glass powder in the wavelength conversion layer is between that of the phosphor particles and the heat sink substrate, and the linear expansion coefficient of the glass powder of the high-temperature sintered silver reflective layer is higher than that of the heat sink substrate and lower than that of the silver powder.

[0020] In one embodiment, the thickness of the wavelength conversion layer is 40-120 μm; and / or the thickness of the glass sintered layer is 1-2 μm; and / or the thickness of the high-temperature sintered silver reflective layer is 10-30 μm; and / or the thickness of the active metal transition layer is 100-500 nm; and / or the thickness of the heat sink substrate is 0.5-3 mm.

[0021] (1) The method for preparing the wavelength conversion device comprises the following steps: coating the surface of the heat sink substrate with an active metal transition layer: coating the surface of the heat sink substrate with an active metal transition layer by magnetron sputtering or evaporation;

[0022] (2) preparing a sintered silver reflective layer slurry: adding silver powder and glass powder into a mortar, adding an organic solvent, grinding and stirring evenly, and then placing the mixture in a planetary mixer for stirring and removing bubbles to obtain a uniformly dispersed sintered silver reflective layer slurry;

[0023] (3) The side of the heat sink substrate covered with the active metal transition layer is covered with a high-temperature sintered silver reflective layer: the sintered silver reflective layer slurry in step (2) is coated on the side of the heat sink substrate covered with the active metal transition layer by screen printing or steel screen printing, and then dried and sintered, so that the sintered silver reflective layer is firmly bonded to the surface of the heat sink substrate and the density of the sintered silver reflective layer is above 98%;

[0024] (4) preparing a glass sintering layer slurry: adding an organic solvent to the low-refractive index glass powder, stirring evenly, and then transferring to a planetary mixer for stirring and removing bubbles, so that the low-refractive index glass powder is evenly dispersed to obtain a glass sintering layer slurry;

[0025] (5) Covering the surface of the high-temperature sintered silver reflective layer with a glass sintered layer: using a screen printing process, a layer of glass sintered layer slurry is coated on the surface of the high-temperature sintered silver reflective layer, and the coating length and / or width of the glass sintered layer slurry is controlled so that the glass sintered layer slurry wraps the high-temperature sintered silver reflective layer, and then baked in an oven to obtain a dry film of the glass sintered layer, and then the heat sink substrate covered with the dry film of the glass sintered layer is placed in a sintering furnace for sintering, so that the glass sintered layer is bonded to the surface of the high-temperature sintered silver reflective layer, and together with the active metal transition layer, the glass sintered layer wraps the high-temperature sintered silver reflective layer;

[0026] (6) preparing fluorescent glass slurry: adding fluorescent powder particles and inorganic glass powder particles into a mortar, adding an organic solvent, grinding and stirring, and then placing in a planetary mixer to stir and remove bubbles, to obtain a uniformly dispersed glass fluorescent slurry;

[0027] (7) Covering the surface of the glass sintered layer with a glass fluorescent layer: Using a screen printing process, a layer of glass fluorescent slurry is coated on the surface of the glass sintered layer, and the coating length and / or width of the glass fluorescent slurry is controlled so that the glass fluorescent wet film wraps the glass sintered layer; then, the glass fluorescent wet film is baked in an oven to obtain a glass fluorescent dry film, and sintered so that the glass fluorescent layer is firmly bonded to the surface of the heat sink substrate to obtain a wavelength conversion device.

[0028] Or the method for preparing the wavelength conversion device comprises the following steps:

[0029] S1. Coating a layer of active metal transition layer on the surface of the heat sink substrate: coating a layer of active metal transition layer on the surface of the heat sink substrate by magnetron sputtering or evaporation;

[0030] S2. Prepare sintered silver reflective layer slurry: add silver powder and glass powder into a mortar, add an organic solvent, grind and stir evenly, place in a planetary mixer and stir to remove bubbles, so as to obtain a uniformly dispersed sintered silver reflective layer slurry;

[0031] S3, the side of the heat sink substrate surface covered with the active metal transition layer is covered with a high-temperature sintered silver reflective layer: the sintered silver reflective layer slurry in step S2 is coated on the side of the heat sink substrate covered with the active metal transition layer by screen printing or steel screen printing process, and dried and sintered, so that the sintered silver reflective layer is firmly bonded to the surface of the heat sink substrate and the density of the sintered silver reflective layer is above 98%;

[0032] S4, preparing glass sintering layer slurry: adding an organic solvent to the low-refractive index glass powder, stirring evenly, and then transferring to a planetary mixer for stirring and removing bubbles, so that the low-refractive index glass powder is evenly dispersed to obtain glass sintering layer slurry;

[0033] S5. Covering the surface of the high-temperature sintered silver reflective layer with a glass sintered layer: covering the surface of the high-temperature sintered silver reflective layer with a layer of glass sintered layer slurry, and controlling the coating length and / or width of the glass sintered layer slurry so that the glass sintered layer slurry wraps the high-temperature sintered silver reflective layer, and a glass sintered layer wet film is formed on the surface;

[0034] S6. Preparation of fluorescent ceramics: adding ceramic powder particles and fluorescent powder particles into a ball mill, adding an organic solvent as a ball milling medium, and mixing the materials uniformly to obtain fluorescent ceramic slurry; placing the fluorescent ceramic slurry in an oven to dry, and then grinding and crushing to obtain fluorescent ceramic dry powder, using SPS sintering technology to obtain fluorescent ceramic block materials, and then slicing, grinding and polishing to obtain ceramic fluorescent sheets;

[0035] S7. Covering the surface of the glass sintered layer with a ceramic fluorescent layer: placing the ceramic fluorescent sheet prepared in step S6 on the surface of the wet film of the glass sintered layer, and then baking it in an oven to obtain a dry film of the glass sintered layer, and then placing the dry film of the glass sintered layer with the ceramic fluorescent sheet attached to the surface into a sintering furnace for sintering, so that the fluorescent ceramic sheet is firmly bonded to the surface of the heat sink substrate by the glass sintered layer, thereby obtaining a wavelength conversion device.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows: the technical solution adopts a high-temperature sintered silver reflective layer as the reflective layer of the wavelength conversion device, which has a higher blue light power resistance capability; the density of the high-temperature sintered silver reflective layer is greater than 98%, which can fully guarantee the reflectivity of the high-temperature sintered silver reflective layer and improve the conversion efficiency of the wavelength conversion device; and the high-temperature sintered silver reflective layer can be used as the bonding layer between the wavelength conversion layer and the heat sink substrate, without the need to design an additional bonding layer, thereby reducing the number of interfaces and thus reducing the interface thermal resistance; the coating length and / or width of the high-temperature sintered silver reflective layer on the heat sink substrate is less than the coating length and / or width of the glass sintered layer, the wavelength conversion layer and the active metal transition layer, which can ensure that the high-temperature sintered silver reflective layer is bonded by the intermediate layer The heat sink substrate is wrapped with an active metal transition layer and a wavelength conversion layer to isolate the corrosion of the high-temperature sintered silver reflective layer by water, oxygen and sulfur substances in the air, thereby improving the reliability of the light-emitting device. The active metal transition layer can improve the interface bonding strength between the heat sink substrate and the high-temperature sintered silver reflective layer to ensure the reliability of the device. On the one hand, the glass sintering layer can isolate the metal silver of the high-temperature sintered silver reflective layer from migrating to the wavelength conversion layer, thereby eliminating the influence of the metal silver migration on the luminous efficiency of the wavelength conversion layer. On the other hand, the densely structured glass sintering layer can completely wrap the high-temperature sintered silver layer, which can isolate the corrosion of the high-temperature sintered silver reflective layer by water vapor, oxygen, sulfur and other substances in the air, such as oxidation and sulfidation, thereby increasing the reliability and stability of the light-emitting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a simplified structural diagram of the wavelength conversion device of Example 1.

[0038] Explanation of the reference numerals: 1. heat sink substrate; 2. active metal transition layer; 3. high temperature sintered silver reflective layer; 4. glass sintered layer; 5. wavelength conversion layer. DETAILED DESCRIPTION

[0039] In order to make the application purpose, technical solution and beneficial technical effect of the present application clearer, the present application is further described in detail in conjunction with the embodiments below. It should be understood that the embodiments described in this specification are only for explaining the present application, not for limiting the present application.

[0040] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unambiguous range; and any lower limit can be combined with other lower limits to form an unambiguous range, and any upper limit can be combined with any other upper limit to form an unambiguous range. In addition, although not explicitly stated, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unambiguous range.

[0041] In the description of this article, it should be noted that, unless otherwise specified, “above” and “below” are inclusive of the number itself, and the “multiple” in “one or more” means more than two.

[0042] The above application content of the present application is not intended to describe each disclosed embodiment or each implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided by a series of examples, which can be used in various combinations. In each example, enumeration is only used as a representative group and should not be interpreted as exhaustive.

[0043] During the research process, the inventors found that the common reflective wavelength conversion devices on the market cannot withstand ultra-high power lasers. The reason is that the wavelength conversion layer and the fluorescent reflection layer are not tolerant enough and the overall reliability of the wavelength conversion layer is poor.

[0044] This application is proposed based on the discovery and research of the above-mentioned problems.

[0045] In a first aspect, the present application provides a wavelength conversion device, comprising a heat sink substrate 1, an active metal transition layer 1, a high-temperature sintered silver reflective layer 3, a glass sintered layer 4 and a wavelength conversion layer 5 stacked in sequence from bottom to top.

[0046] Wavelength conversion layer 5: It can be a glass fluorescent layer made by sintering inorganic glass powder and phosphor particles, or it can be a ceramic fluorescent layer made by high-temperature sintering of ceramic powder particles and phosphor particles, which has good high temperature resistance and good heat dissipation. The wavelength conversion layer 5 can also contain a certain amount of added particles such as aluminum oxide, titanium oxide, silicon oxide, zinc oxide, magnesium oxide, zirconium oxide, etc. The wavelength conversion layer 5 is preferably a glass fluorescent layer, and the sintering temperature can be lower. When the wavelength conversion layer 5 is a glass fluorescent layer, the sintering temperature of the inorganic glass powder must be lower than the sintering temperature of the glass powder of the high-temperature sintered silver reflective layer and the low-refractive index glass powder in the glass sintered layer. The coating length and / or width of the wavelength conversion layer 5 on the heat sink substrate 1 must be larger than the coating length and / or width of the high-temperature sintered silver reflective layer so as to completely wrap the high-temperature sintered silver reflective layer 3. The linear expansion coefficient of the inorganic glass powder in the glass fluorescent layer is preferably between that of the phosphor particles and the heat sink substrate, specifically (30-80)*10 -7 / ℃.

[0047] The glass sintering layer 4 is a sintering layer of low-refractive index glass powder, which is a powder of inorganic glass powder with a refractive index not higher than that of the glass fluorescent layer, and can be a combination of two or more of aluminum oxide, silicon oxide, zinc oxide, boron oxide and the like. Silver in the high-temperature sintered silver reflective layer 3 is an active metal, which is easy to migrate to the wavelength conversion layer 5, reducing the luminous efficiency of the wavelength conversion layer 5, while the glass sintering layer 4 is a pure glass layer with a dense structure, which can isolate the silver layer from migrating to the wavelength conversion layer 5, thereby eliminating the influence of the migration of metal silver on the luminous efficiency of the wavelength conversion layer 5; the glass sintering layer 4 with a dense structure completely wraps the high-temperature sintered silver layer 3, which can isolate the corrosion effects of water vapor, oxygen and sulfur in the air on the high-temperature sintered silver reflective layer such as oxidation and sulfidation, thereby increasing the reliability and stability of the light-emitting device. The refractive index of the low-refractive index glass powder is preferably not higher than the refractive index of the inorganic glass powder of the glass fluorescent layer. For example, a low-refractive index glass powder (refractive index below 1.6) with a main content of silicon oxide is preferred, which can improve the extraction efficiency of fluorescence in the glass fluorescent layer and increase the light output in the wavelength conversion layer 5. The sintering temperature of the low-refractive index glass powder is lower than the sintering temperature of the glass powder in the high-temperature sintered silver reflective layer 3, but higher than the sintering temperature of the inorganic glass powder in the wavelength conversion layer 5. The coating length and / or width of the glass sintered layer 4 on the heat sink substrate 1 needs to be larger than the coating length and / or width of the high-temperature sintered silver reflective layer 3 so as to completely wrap the high-temperature sintered silver reflective layer 3. The coating length and / or width of the glass sintered layer 4 on the heat sink substrate 1 can be the same as or narrower than the coating length and / or width of the wavelength conversion layer 5. The thickness of the glass sintered layer 4 is preferably 1-2um.

[0048] The high-temperature sintered silver reflective layer 3 is obtained by sintering glass powder and silver powder at above 800°C, and the mass ratio of silver powder to glass powder in the reflective silver layer is (97-99.5): (0.5-3). Compared with the silver-plated reflective layer (the silver-plated reflective layer can only withstand temperatures below 250°C, and can therefore only be adapted to the organic silicone fluorescent light-emitting layer with poor thermal conductivity), the high-temperature sintered silver reflective layer 3 has higher temperature resistance and can be adapted to glass fluorescent layers and ceramic fluorescent layers with high thermal conductivity and good temperature resistance. The wavelength conversion device prepared has higher blue light power resistance. Compared with the diffuse reflection layer and the dielectric film reflection layer, the high-temperature sintered silver reflective layer 3 also has a higher thermal conductivity, and the wavelength conversion device has better thermal conductivity and heat dissipation effects. The better the thermal quenching resistance of the fluorescent layer of the prepared wavelength conversion device, the higher the laser power density resistance. The high-temperature sintered silver reflective layer 3 can be used as a fluorescent reflection part and as a bonding layer between the wavelength conversion layer and the heat sink substrate. There is no need to design an additional bonding layer, which reduces the number of interfaces and thus reduces the interface thermal resistance. The density of the high-temperature sintered silver reflective layer 3 is greater than 98%, which can fully ensure the reflectivity of the high-temperature sintered silver reflective layer and improve the conversion efficiency of the wavelength conversion device. The silver powder includes a first silver powder and a second silver powder with two particle size ranges of coarse and fine particles. The median diameter of the first silver powder is 0.5-5μm, and the median diameter of the second silver powder is 20-200nm. The combination of these two coarse and fine particles of silver powder can ensure the density of the high-temperature sintered silver reflective layer 3 and improve the sintering activity, and improve the reflectivity of the high-temperature sintered silver reflective layer 3 at the lowest temperature possible. The comprehensive specific surface area of ​​the two silver powders is 1-2m 2 / g, the full melting temperature of the glass powder is 700-800℃, for example, the glass powder can be made of Si-Al-Zn-BO material, so that the sintering temperature of the glass powder and the silver powder can be adapted. The coating length and / or width of the high-temperature sintered silver reflective layer 3 on the heat sink substrate 1 is smaller than the coating length and / or width of the glass sintered layer 4, the wavelength conversion layer 5 and the active metal transition layer 2, ensuring that the high-temperature sintered silver reflective layer 3 is wrapped by the glass sintered layer 4, the active metal transition layer 2 and the wavelength conversion layer 5, isolating the high-temperature sintered silver reflective layer 3 from the corrosion of water, oxygen and sulfur substances in the air, and improving the reliability of the light-emitting device.

[0049] The active metal transition layer 2 is a titanium layer, a nickel layer, or a chromium layer, and is located between the high-temperature sintered silver reflective layer 3 and the heat sink substrate 1, and can improve the interfacial bonding strength between the heat sink substrate 1 and the high-temperature sintered silver reflective layer 3. The valence bond of the high-temperature sintered silver reflective layer 3 is mainly a metal bond, while the heat sink substrate 1 is a ceramic or inorganic material, and its valence bond is mainly a covalent bond. The affinity between the metal bond and the covalent bond is poor, and the substrate bonding of the two valence bond forms has a weak interfacial bonding strength. The reason why designing an active metal transition layer 2 between the two can improve the bonding strength between the heat sink substrate 1 and the high-temperature sintered silver reflective layer 3 is that the active metal can form an alloy bond with the silver in the high-temperature sintered silver reflective layer 3, and can also capture the oxygen in the glass phase component of the high-temperature sintered silver reflective layer 3 to form an oxide covalent bond. In addition, since the material structure of the surface layer of the heat sink substrate 1 usually has defects, it is conducive to the enrichment of oxygen molecules, so an oxide layer is formed on the surface of the heat sink substrate 1, and the oxygen in this oxide layer is easily captured by the highly active metal to form an oxide covalent bond. Under the combined effect of the two, an active metal oxide and alloy transition layer is formed between the heat sink substrate 1 and the high temperature sintered silver reflective layer 3, thereby improving the bonding strength between the heat sink substrate 1 and the high temperature sintered silver reflective layer 3. The coating length and / or width of the active metal transition layer 2 on the heat sink substrate 1 is greater than the coating length and / or width of the high temperature sintered silver reflective layer 3, thereby wrapping the high temperature sintered silver reflective layer 3 together with the wavelength conversion layer 5 and the glass sintered layer 4. The active metal transition layer 2 is preferably a metal titanium layer. The thickness of the active metal transition layer 2 is preferably 100-500nm.

[0050] The heat sink substrate 1 is used as a heat-conducting and heat-dissipating layer of the wavelength conversion device. A ceramic substrate or an inorganic material substrate with a thermal conductivity exceeding 30w / m·k is selected to ensure that the heat generated during the operation of the wavelength conversion layer can be promptly conducted out through the heat sink substrate. The substrate can withstand high temperatures above 900°C without damage, thereby ensuring that the sintering process of the high-temperature silver reflective layer 3 will not cause damage to the heat sink substrate 1. Specifically, the heat sink substrate 1 can be a single crystal silicon substrate, a diamond substrate, a silicon nitride substrate, an aluminum nitride substrate, a sapphire substrate, etc. The surface roughness of the heat sink substrate Ra≤0.1μm, and the shape can be annular, circular, square, etc., preferably annular and circular, and the thickness is preferably 0.5-3mm.

[0051] Since all the layers of the wavelength conversion device of the technical solution are made of high thermal conductivity materials, the device can be used as a static wavelength conversion device, and has a simple structure, with only a high thermal conductivity substrate layer (heat sink substrate 1) + a high thermal conductivity reflective layer (high-temperature sintered silver reflective layer 3) + a fluorescent layer (wavelength conversion layer 5) (the thickness of the active metal transition layer and the glass sintered layer are very thin, and the interface thermal resistance is very low. They can be regarded as modified layers, and the interface thermal resistance can be ignored). There are no other solder layers and low-temperature silver adhesive layers. The device has fewer longitudinal interfaces, lower interface thermal resistance, better thermal conductivity and heat dissipation effects, and higher resistance to laser power density, making it suitable for high-power and ultra-high-power laser lighting scenarios.

[0052] When the wavelength conversion layer 5 is a glass fluorescent layer, the preparation method of the wavelength conversion device comprises the following steps:

[0053] (1) A layer of active metal transition layer 2 is coated on the surface of the heat sink substrate 1: A layer of active metal transition layer 2 is coated on the surface of the heat sink substrate by magnetron sputtering or evaporation. Preferably, the magnetron sputtering method is used, and the active metal transition layer 2 with a thickness of 100-500 nm is obtained by controlling the sputtering power and the coating time.

[0054] (2) Preparing a sintered silver reflective layer slurry: Add silver powder and glass powder to a mortar, add an organic solvent, grind and stir evenly, and place in a planetary mixer to stir and remove bubbles to obtain a uniformly dispersed sintered silver reflective layer slurry. Preferably, a set ratio of the first silver powder, the second silver powder, and the glass powder are added to a mortar, and a set mass of an organic solvent such as terpineol is added. After manually grinding and stirring for 10-30 minutes to mix evenly, the slurry is placed in a planetary mixer to stir and remove bubbles to obtain a uniformly dispersed sintered silver reflective layer slurry.

[0055] (3) The active metal transition layer 2 is coated on the surface of the heat sink substrate 1, and the high-temperature sintered silver reflective layer 3 is coated on one side: the sintered silver reflective layer slurry in step (2) is coated on the side of the heat sink substrate covered with the active metal transition layer 2 by screen printing or steel screen printing, and dried and sintered, so that the sintered silver reflective layer is firmly bonded to the surface of the heat sink substrate and the density of the sintered silver reflective layer is above 98%. Preferably, a screen printing process is used to control the viscosity of the sintered silver reflective layer slurry, the screen plate parameters and the printing process parameters, so that a sintered silver reflective layer wet film with a thickness of 10-30μm is coated on the side of the heat sink substrate covered with the active metal transition layer. The drying condition of the wet film is preferably to bake at 110-130℃ in an oven for 30-60min, so as to obtain a dry film of the silver reflective layer. The sintering condition is preferably to sinter in a sintering furnace, in an air atmosphere, and set the sintering insulation temperature to 850-900℃, and the sintering time is 30-60min.

[0056] (4) preparing the glass sintering layer slurry: adding an organic solvent to the low-refractive index glass powder, stirring evenly, and then transferring to a planetary mixer to stir and remove bubbles, so that the low-refractive index glass powder is evenly dispersed, and the glass sintering layer slurry is obtained. Specifically, it can be: adding an organic solvent such as pine oil alcohol to the low-refractive index glass powder, manually grinding in a mortar for 10-30 minutes, and then transferring the glass sintering layer slurry to a planetary mixer to stir and remove bubbles, so that the low-refractive index glass powder is evenly dispersed, and the glass sintering layer slurry is obtained.

[0057] (5) Covering the surface of the high-temperature sintered silver reflective layer 3 with a glass sintered layer 4: Using a screen printing process, a layer of glass sintered layer slurry is coated on the surface of the high-temperature sintered silver reflective layer 3, and the coating length and / or width of the glass sintered layer slurry is controlled so that the glass sintered layer slurry wraps the high-temperature sintered silver reflective layer, and then baked in an oven to obtain a glass sintered layer dry film, and then the heat sink substrate covered with the glass sintered layer dry film is placed in a sintering furnace for sintering, so that the glass sintered layer 4 is bonded to the surface of the high-temperature sintered silver reflective layer 3, and together with the active metal transition layer 2, the high-temperature sintered silver reflective layer 3 is wrapped. The preferred conditions for oven baking are baking at 110-130°C for 30-60 minutes. The preferred conditions for sintering in a sintering furnace are: in an air atmosphere, the insulation temperature is 750-800°C, and the sintering time is 20-60 minutes.

[0058] (6) Preparing fluorescent glass slurry: Add fluorescent powder particles and inorganic glass powder particles into a mortar, add an organic solvent such as pine oil, grind and stir, and place in a planetary mixer to stir and remove bubbles to obtain a uniformly dispersed glass fluorescent slurry.

[0059] (7) The surface of the glass sintered layer 4 is coated with a glass fluorescent layer: a screen printing process is used to coat the surface of the glass sintered layer with a layer of glass fluorescent slurry, and the coating length and / or width of the glass fluorescent slurry is controlled so that the glass fluorescent wet film wraps the glass sintered layer; then, the glass fluorescent wet film is baked in an oven to obtain a glass fluorescent dry film, and sintered so that the glass fluorescent layer is firmly bonded to the surface of the heat sink substrate to obtain a wavelength conversion device. Preferably, the baking conditions in the oven are 110-130°C for 30-60 minutes, and the sintering conditions are: sintering at 700-800°C for 30-60 minutes in an air atmosphere.

[0060] When the wavelength conversion layer 5 is a ceramic fluorescent layer, the preparation method of the wavelength conversion device comprises the following steps:

[0061] S1. Coating a layer of active metal transition layer 2 on the surface of the heat sink substrate 1: Coating a layer of active metal transition layer 2 on the surface of the heat sink substrate 1 by magnetron sputtering or evaporation.

[0062] S2. Prepare sintered silver reflective layer slurry: add silver powder and glass powder into a mortar, add an organic solvent, grind and stir evenly, place in a planetary mixer and stir to remove bubbles, so as to obtain a uniformly dispersed sintered silver reflective layer slurry.

[0063] S3. The surface of the heat sink substrate 1 is covered with an active metal transition layer 2 and one side is covered with a high-temperature sintered silver reflective layer 3: the sintered silver reflective layer slurry in step S2 is coated on the side of the heat sink substrate covered with the active metal transition layer by screen printing or steel screen printing, and then dried and sintered, so that the sintered silver reflective layer is firmly bonded to the surface of the heat sink substrate and the density of the sintered silver reflective layer is above 98%.

[0064] S4. Prepare glass sintering layer slurry: add organic solvent to low-refractive index glass powder, stir evenly, and then transfer to a planetary mixer for stirring and removing bubbles, so that the low-refractive index glass powder is evenly dispersed to obtain glass sintering layer slurry.

[0065] S5, coating the surface of the high-temperature sintered silver reflective layer 3 with a glass sintered layer 4: coating the surface of the high-temperature sintered silver reflective layer 3 with a layer of glass sintered layer slurry, controlling the coating length and / or width of the glass sintered layer slurry, so that the glass sintered layer slurry wraps the high-temperature sintered silver reflective layer, and a glass sintered layer wet film is formed on the surface;

[0066] S6. Preparation of fluorescent ceramics: adding ceramic powder particles and phosphor particles into a ball mill, adding an organic solvent (such as anhydrous ethanol) as a ball milling medium, and obtaining a fluorescent ceramic slurry after uniformly mixing the materials through ball milling; placing the fluorescent ceramic slurry in an oven to dry, and then grinding and crushing it to obtain fluorescent ceramic dry powder, using SPS sintering technology to obtain fluorescent ceramic block materials, and then slicing, grinding and polishing to obtain ceramic fluorescent sheets.

[0067] S7, the surface of the glass sintered layer 4 is covered with a ceramic fluorescent layer: the ceramic fluorescent sheet prepared in step S6 is placed on the surface of the wet film of the glass sintered layer, and then baked in an oven to obtain a dry film of the glass sintered layer, and then the dry film of the glass sintered layer with the ceramic fluorescent sheet attached to the surface is placed in a sintering furnace for sintering, so that the fluorescent ceramic sheet is firmly bonded to the surface of the heat sink substrate by the glass sintered layer, and a wavelength conversion device is obtained. Preferably, the baking conditions in the oven are 110-130°C for 30-60 minutes. Preferably, the sintering conditions in the sintering furnace are: in an air atmosphere, the sintering insulation temperature is 750-800°C, and the sintering time is 20-60 minutes.

[0068] In order to allow those skilled in the art to better understand this solution, the solution is further described in detail below in conjunction with specific examples. The process methods used in the examples are all conventional methods unless otherwise specified; the materials used are all commercially available unless otherwise specified.

[0069] The high temperature sintered silver reflective layer 3 described in the following embodiments is subjected to a density test using the national standard GB / T 3850. Example 1

[0070] like Figure 1 As shown, this embodiment discloses a wavelength conversion device, including a heat sink substrate 1, an active metal transition layer 2, a high-temperature sintered silver reflective layer 3, a glass sintered layer 4 and a wavelength conversion layer 5 stacked in sequence from bottom to top.

[0071] The heat sink substrate 1 is an aluminum nitride substrate with a surface roughness Ra≤0.1 μm and a linear expansion coefficient of (56-60)*10 -7 / ℃, the shape is ring-shaped and the thickness is 1mm.

[0072] The active metal transition layer 2 is a titanium layer with a thickness of 200 nm.

[0073] The high-temperature sintered silver reflective layer 3 is obtained by sintering silver powder and glass at a mass ratio of 98:2 at 850°C. The density of the high-temperature sintered silver reflective layer 3 is 99.3%. The silver powder includes a first silver powder and a second silver powder. The median diameter of the first silver powder is 3μm, the median diameter of the second silver powder is 100nm, and the mass ratio of the first silver powder to the second silver powder is 6:1. The comprehensive specific surface area of ​​the silver powder is 1-2m 2 / g, linear expansion coefficient is 190*10 -7 / ℃, the glass powder is Si-Al-Zn-BO series glass powder, the full melting temperature is 700-800℃, and the linear expansion coefficient is (65-75)*10 -7 / ℃; the thickness of the high temperature sintered silver reflective layer is 20μm.

[0074] The glass sintered layer 4 is a sintered layer of a glass phase mixture of silicon oxide and aluminum oxide, the ratio of the two is about 3:1, and the thickness of the glass sintered layer is 1 μm.

[0075] The wavelength conversion layer 5 is a sintered layer of a mixture of inorganic glass powder (Zn-B-Si-O system), phosphor (YAG yellow powder), and aluminum oxide, and the mass ratio of inorganic glass powder, phosphor, and aluminum oxide is about 1:3:0.2. The linear expansion coefficient of the inorganic glass powder is (65-70)*10 -7 / ℃, the refractive index is about 1.65; the linear expansion coefficient of the phosphor is 75*10 -7 / ° C. The thickness of the wavelength conversion layer 5 is 80 μm.

[0076] The coating length and / or width of the wavelength conversion layer 5, glass sintered layer 4, high temperature sintered silver reflective layer 3, and active metal transition layer 2 on the heat sink substrate 1 are: high temperature sintered silver reflective layer 3 < glass sintered layer 4 / active metal transition layer 2 ≤ wavelength conversion layer 5.

[0077] The preparation method of the wavelength conversion device described in this embodiment is as follows:

[0078] (1) A layer of active metal transition layer 2 is coated on the surface of the heat sink substrate 1: A titanium metal layer with a thickness of 200 nm is coated on the surface of the aluminum nitride substrate of the circular heat sink substrate with a thickness of about 1 mm by controlling the sputtering power and coating time using a magnetron sputtering method.

[0079] (2) preparing a sintered silver reflective layer slurry: adding the first silver powder, the second silver powder and the glass powder in the above proportions into a mortar, adding pinene alcohol (the amount is 35% of the total amount of the silver powder), manually grinding and stirring for 10-30 minutes to mix evenly, and then placing the mixture in a planetary mixer to stir and remove bubbles, thereby obtaining a uniformly dispersed sintered silver reflective layer slurry.

[0080] (3) The active metal transition layer 2 is coated on the surface of the heat sink substrate 1, and a high-temperature sintered silver reflective layer 3 is coated on one side of the heat sink substrate covered with the active metal transition layer: a sintered silver reflective layer wet film with a thickness of 20 μm is coated on the side of the heat sink substrate covered with the active metal transition layer by a screen printing process, by controlling the viscosity of the sintered silver reflective layer slurry, the screen plate parameters and the printing process parameters, and then baked in an oven at 120° C. for 30-60 min to obtain a silver reflective layer dry film, and then sintered in a sintering furnace in an air atmosphere, setting the sintering insulation temperature to 850-900° C. and the sintering time to 30-60 min, so that the sintered silver reflective layer is firmly bonded to the surface of the heat sink substrate and the density of the sintered silver reflective layer is 99.3%.

[0081] (4) preparing a slurry for a glass sintering layer: adding an organic solvent, pinene alcohol, to a low-refractive-index glass powder, grinding the powder manually in a mortar for 10 to 30 minutes, stirring the powder evenly, and transferring the mixture to a planetary mixer for stirring and removing bubbles, so that the low-refractive-index glass powder is evenly dispersed to obtain a slurry for a glass sintering layer.

[0082] (5) Covering the surface of the high-temperature sintered silver reflective layer 3 with a glass sintered layer 4: Using a screen printing process, controlling the viscosity of the glass sintered layer slurry, screen plate parameters and printing process parameters, covering the surface of the high-temperature sintered silver reflective layer 3 with a 1 μm glass sintered layer slurry, controlling the coating length and / or width of the glass sintered layer slurry so that the glass sintered layer slurry wraps the high-temperature sintered silver reflective layer, and then baking in an oven at 120° C. for 30-60 min to obtain a dry film of the glass sintered layer, and then placing the heat sink substrate covered with the dry film of the glass sintered layer in a sintering furnace for sintering in an air atmosphere at a holding temperature of 750-800° C. for 30 min, so that the glass sintered layer adheres to the surface of the high-temperature sintered silver reflective layer 3 and wraps the high-temperature sintered silver reflective layer 3 together with the active metal transition layer 2.

[0083] (6) Preparation of fluorescent glass slurry: Add fluorescent powder particles, inorganic glass powder particles and alumina into a mortar according to the above proportions, add organic solvent pineneol (the dosage is 22% of the fluorescent powder particles), grind and stir manually for 10-30 minutes, and then place in a planetary mixer to stir and remove bubbles to obtain a uniformly dispersed glass fluorescent slurry.

[0084] (7) Covering the surface of the glass sintered layer 4 with a glass fluorescent layer: Using a screen printing process, controlling the viscosity of the glass fluorescent slurry, the screen plate parameters and the printing process parameters, a layer of 80 μm glass fluorescent slurry is coated on the surface of the glass sintered layer 4, and controlling the coating length and / or width of the glass fluorescent slurry so that the glass fluorescent wet film wraps the glass sintered layer; then, baking the glass fluorescent wet film in an oven at 120° C. for 30-60 min to obtain a glass fluorescent dry film, and then sintering it in a sintering furnace at 700-800° C. for 30-60 min in an air atmosphere, so that the glass fluorescent layer is firmly bonded to the surface of the heat sink substrate 1, thereby obtaining a wavelength conversion device. Example 2

[0085] This embodiment 2 discloses a wavelength conversion device, including a heat sink substrate 1, an active metal transition layer 2, a high-temperature sintered silver reflective layer 3, a glass sintered layer 4 and a wavelength conversion layer 5 stacked in sequence from bottom to top. Its structure and preparation method are substantially the same as those of embodiment 1, except that the high-temperature reflective silver layer 3 is different. The high-temperature sintered silver reflective layer 3 of this embodiment 2 is obtained by sintering silver powder and glass at a mass ratio of 99.5:0.5 at 850°C. The density of the high-temperature sintered silver reflective layer 3 is 98.3%. The silver powder includes a first silver powder and a second silver powder. The median diameter of the first silver powder is 0.5μm, the median diameter of the second silver powder is 50nm, and the mass ratio of the first silver powder to the second silver powder is 8:1. The comprehensive specific surface area of ​​the silver powder is 1-2m 2 / g, linear expansion coefficient is 190*10 -7 / ℃, the glass powder is Si-Al-Zn-BO series glass powder, the full melting temperature is 700-800℃, and the linear expansion coefficient is (65-75)*10 -7 / ℃; the thickness of the high temperature sintered silver reflective layer 3 is 30μm. Example 3

[0086] This embodiment 3 discloses a wavelength conversion device, including a heat sink substrate 1, an active metal transition layer 2, a high-temperature sintered silver reflective layer 3, a glass sintered layer 4 and a wavelength conversion layer 5 stacked in sequence from bottom to top. Its structure and preparation method are substantially the same as those of embodiment 1, except that the high-temperature reflective silver layer 3 is different. The high-temperature sintered silver reflective layer 3 of this embodiment 3 is obtained by sintering silver powder and glass at a mass ratio of 97:3 at 850°C. The density of the high-temperature sintered silver reflective layer 3 is 99.6%. The silver powder includes a first silver powder and a second silver powder. The median diameter of the first silver powder is 5μm, the median diameter of the second silver powder is 200nm, and the mass ratio of the first silver powder to the second silver powder is 3:1. The comprehensive specific surface area of ​​the silver powder is 1-2m 2 / g, linear expansion coefficient is 190*10 -7 / ℃, the glass powder is Si-Al-Zn-BO series glass powder, the full melting temperature is 700-800℃, and the linear expansion coefficient is (65-75)*10 -7 / ℃; the thickness of the high temperature sintered silver reflective layer 3 is 10μm. Example 4

[0087] This embodiment 4 discloses a wavelength conversion device, including a heat sink substrate 1, an active metal transition layer 2, a high-temperature sintered silver reflective layer 3, a glass sintered layer 4 and a wavelength conversion layer 5 stacked in sequence from bottom to top. Its structure and preparation method are substantially the same as those of embodiment 1, except that the high-temperature reflective silver layer 3 is different. The high-temperature sintered silver reflective layer 3 of this embodiment 4 is obtained by sintering silver powder and glass at a mass ratio of 99:1 at 850°C. The density of the high-temperature sintered silver reflective layer is 99%. The silver powder includes a first silver powder and a second silver powder. The median diameter of the first silver powder is 1μm, the median diameter of the second silver powder is 20nm, and the mass ratio of the first silver powder to the second silver powder is 6:1. The comprehensive specific surface area of ​​the silver powder is 1-2m 2 / g, linear expansion coefficient is 190*10 -7 / ℃, the glass powder is Si-Al-Zn-BO series glass powder, the full melting temperature is 700-800℃, and the linear expansion coefficient is (65-75)*10 -7 / ℃; the thickness of the high temperature sintered silver reflective layer is 20μm. Example 5

[0088] This embodiment 5 discloses a wavelength conversion device, including a heat sink substrate 1, an active metal transition layer 2, a high-temperature sintered silver reflective layer 3, a glass sintered layer 4 and a wavelength conversion layer 5 which are stacked in sequence from bottom to top.

[0089] The heat sink substrate 1 is an aluminum nitride substrate with a surface roughness Ra≤0.1 μm and a linear expansion coefficient of (56-60)*10 -7 / ℃, the shape is ring-shaped and the thickness is 3mm.

[0090] The active metal transition layer 2 is a titanium layer with a thickness of 500 nm.

[0091] The high temperature sintered silver reflective layer 3 is the same as that in the first embodiment.

[0092] The glass sintered layer 4 is a sintered layer of a glass phase mixture of silicon oxide and aluminum oxide, the ratio of the two is about 3:1, and the thickness of the glass sintered layer is 2 μm.

[0093] The wavelength conversion layer is a sintered layer of a mixture of inorganic glass powder (Zn-B-Si-O system), phosphor (YAG yellow powder), and alumina, and the mass ratio of inorganic glass powder, phosphor, and alumina is about 1:1:0.1. The linear expansion coefficient of the inorganic glass powder is (65-70)*10 -7 / ℃, the refractive index is about 1.65; the linear expansion coefficient of the phosphor is 75*10 -7 / °C. The thickness of the wavelength conversion layer is 120 μm.

[0094] The coating length and / or width of the wavelength conversion layer 5, glass sintered layer 4, high temperature sintered silver reflective layer 3, and active metal transition layer 2 on the heat sink substrate 1 are: high temperature sintered silver reflective layer 3 < glass sintered layer 4 / active metal transition layer 2 ≤ wavelength conversion layer 5. Example 6

[0095] This embodiment 6 discloses a wavelength conversion device, including a heat sink substrate 1, an active metal transition layer 2, a high-temperature sintered silver reflective layer 3, a glass sintered layer 4 and a wavelength conversion layer 5 which are stacked in sequence from bottom to top.

[0096] The heat sink substrate 1 is an aluminum nitride substrate with a surface roughness Ra≤0.1 μm and a linear expansion coefficient of (56-60)*10 -7 / ℃, the shape is ring-shaped and the thickness is 0.5mm.

[0097] The active metal transition layer 2 is a titanium layer with a thickness of 100 nm.

[0098] The high temperature sintered silver reflective layer 3 is the same as that in the first embodiment.

[0099] The glass sintered layer 4 is the same as that in Example 1.

[0100] The wavelength conversion layer 5 is a sintered layer of a mixture of inorganic glass powder (Zn-B-Si-O system), phosphor (YAG yellow powder), and aluminum oxide, and the mass ratio of inorganic glass powder, phosphor, and aluminum oxide is about 1:6:0.3. The linear expansion coefficient of the inorganic glass powder is (65-70)*10 -7 / ℃, the refractive index is about 1.65; the linear expansion coefficient of the phosphor is 75*10 -7 / °C. The thickness of the wavelength conversion layer is 40 μm.

[0101] The coating length and / or width of the wavelength conversion layer 5, glass sintered layer 4, high temperature sintered silver reflective layer 3, and active metal transition layer 4 on the heat sink substrate 1 are: high temperature sintered silver reflective layer 3 < glass sintered layer 4 / active metal transition layer 2 ≤ wavelength conversion layer 5. Example 7

[0102] This embodiment 7 discloses a wavelength conversion device, including a heat sink substrate 1, an active metal transition layer 2, a high-temperature sintered silver reflective layer 3, a glass sintered layer 4 and a wavelength conversion layer 5 which are stacked in sequence from bottom to top.

[0103] The heat sink substrate 1 is a single crystal silicon substrate with a surface roughness Ra≤0.1 μm and a linear expansion coefficient of 2.6*10 -6 / ℃*10 -7 / ℃, the shape is ring-shaped and the thickness is 1mm.

[0104] The active metal transition layer 2 is a chromium layer with a thickness of 200 nm.

[0105] The high temperature sintered silver reflective layer 3 is the same as that in the first embodiment.

[0106] The glass sintered layer 4 is the same as that in Example 1.

[0107] The wavelength conversion layer 5 is a ceramic fluorescent layer, which is obtained by sintering a sintered layer of a mixture of ceramic powder particles (alumina) and fluorescent powder particles (YAG yellow powder). The mass ratio of ceramic powder particles to fluorescent powder is about 1:1.

[0108] The coating length and / or width of the wavelength conversion layer 5, glass sintered layer 4, high temperature sintered silver reflective layer 4, and active metal transition layer 2 on the heat sink substrate 1 are: high temperature sintered silver reflective layer 3 < glass sintered layer 4 / active metal transition layer 2 ≤ wavelength conversion layer 5.

[0109] The preparation method of the wavelength conversion device comprises the following steps:

[0110] (1) The surface of the heat sink substrate 1 is coated with an active metal transition layer 2: a chromium layer of the active metal transition layer 2 is plated on the surface of the heat sink substrate 1 by magnetron sputtering or evaporation.

[0111] (2) Preparing a sintered silver reflective layer slurry: Add silver powder and glass powder into a mortar, add an organic solvent, grind and stir evenly, and place in a planetary mixer to stir and remove bubbles to obtain a uniformly dispersed sintered silver reflective layer slurry.

[0112] (3) The surface of the heat sink substrate 1 is covered with an active metal transition layer 2 and one side thereof is covered with a high-temperature sintered silver reflective layer 3: the sintered silver reflective layer slurry in step S2 is coated on the side of the heat sink substrate covered with the active metal transition layer by screen printing or steel screen printing, and then dried and sintered, so that the sintered silver reflective layer 3 is firmly bonded to the surface of the heat sink substrate 1 and the density of the sintered silver reflective layer 3 is above 99.3%.

[0113] (4) preparing a slurry for a glass sintering layer: adding an organic solvent to a low-refractive index glass powder, stirring the mixture evenly, and transferring the mixture to a planetary mixer for stirring and removing bubbles, so that the low-refractive index glass powder is evenly dispersed to obtain a slurry for a glass sintering layer.

[0114] (5) Covering the surface of the high-temperature sintered silver reflective layer 3 with a glass sintered layer 4: Covering the surface of the high-temperature sintered silver reflective layer 3 with a layer of glass sintered layer slurry, and controlling the coating length and / or width of the glass sintered layer slurry so that the glass sintered layer slurry wraps the high-temperature sintered silver reflective layer, and a glass sintered layer wet film is formed on the surface;

[0115] (6) Preparation of fluorescent ceramics: Ceramic powder particles and phosphor particles are added to a ball mill, and an organic solvent (such as anhydrous ethanol) is added as a ball milling medium. The mixture is ball milled for 12 hours to obtain a fluorescent ceramic slurry. The fluorescent ceramic slurry is placed in an oven and dried at 70°C for 24 hours, and then ground and crushed, and passed through a 200-mesh sieve to obtain a fluorescent ceramic dry powder. The fluorescent ceramic block material is obtained by SPS sintering technology, and then sliced, ground and polished to obtain a 120-μm thick ceramic fluorescent sheet.

[0116] (7) The surface of the glass sintered layer 4 is covered with a ceramic fluorescent layer: the ceramic fluorescent sheet prepared in step S6 is placed on the surface of the wet film of the glass sintered layer, and then baked in an oven at 120°C for 30-60 minutes to obtain a dry film of the glass sintered layer. The dry film of the glass sintered layer with the ceramic fluorescent sheet attached to the surface is then placed in a sintering furnace for sintering in an air atmosphere at a sintering insulation temperature of 750-800°C for 30 minutes, so that the fluorescent ceramic sheet is firmly bonded to the surface of the heat sink substrate 1 by means of the glass sintered layer 4, thereby obtaining a wavelength conversion device. Comparative Example 1

[0117] A wavelength conversion device comprises a heat sink substrate 1, an active metal transition layer 2, a high temperature sintered silver reflection layer 3, a glass sintered layer 4 and a wavelength conversion layer 5 which are sequentially stacked from bottom to top. The structure and preparation method of this comparative example 1 are substantially the same as those of Example 1, except that the coating width of the wavelength conversion layer 1, the glass sintered layer 2, the high temperature sintered silver reflection layer 3 and the active metal transition layer 4 on the heat sink substrate 1 in this comparative example 1 is: high temperature sintered silver reflection layer 3 = glass sintered layer 4 = active metal transition layer 2 = wavelength conversion layer 5. Comparative Example 2

[0118] A wavelength conversion device comprises a heat sink substrate 1, an active metal transition layer 2, a high temperature sintered silver reflective layer 3, a glass sintered layer 4 and a wavelength conversion layer 5 which are sequentially stacked from bottom to top. The structure and preparation method of the comparative example 1 are substantially the same as those of the embodiment 1, except that the silver powder of the high temperature sintered silver reflective layer 3 of the comparative example 2 is different. The silver powder of the comparative example 2 only uses silver powder with a median diameter of 3 μm, and the density of the obtained high temperature sintered silver reflective layer is 88%.

[0119] The wavelength conversion devices prepared in each embodiment and each comparative example were subjected to performance tests, and the test items were as follows:

[0120] (1) Test for tolerance to extreme blue light power: adjust the blue light power to a lower range, then continuously increase the blue light power and observe the change in luminous flux. When the luminous flux stops increasing or even decreases, record the blue light power, which is the limit value of the blue light power tolerance of the wavelength conversion device (i.e., the extreme blue light power). The luminous flux corresponding to the extreme blue light power is the extreme luminous flux.

[0121] (2) Luminous flux test at 30W blue light power: Light up the light source and align the light outlet of the light source with the entrance of the integrating sphere so that the light completely enters the integrating sphere. Test the luminous flux of the wavelength conversion device at 30W low blue light power.

[0122] (3) Aging cycle reliability test: Test the change in the luminous flux of the wavelength conversion device before and after aging under high-temperature and low-temperature cycles. When the luminous flux after aging drops to 90% of that before aging, it is the tolerable limit aging time. Calculate the number of cycles to evaluate its reliability. High and low temperature test environment: high temperature 85℃, low temperature -40℃. One cycle 2h.

[0123] The test results are shown in Table 1

[0124] Table 1

[0125] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the claims of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A wavelength conversion device, characterized in that: The invention comprises a heat sink substrate, an active metal transition layer, a high-temperature sintered silver reflective layer, a glass sintered layer and a wavelength conversion layer which are sequentially stacked from bottom to top, wherein the high-temperature sintered silver reflective layer is obtained by sintering glass powder and silver powder at above 800°C, the density of the high-temperature sintered silver reflective layer is greater than 98%, the coating length and / or width of the high-temperature sintered silver reflective layer on the heat sink substrate is smaller than the coating length and / or width of the glass sintered layer, the wavelength conversion layer and the active metal transition layer, the heat sink substrate is a ceramic substrate or an inorganic material substrate with a thermal conductivity exceeding 30w / m·k, the wavelength conversion layer is a glass fluorescent layer obtained by sintering inorganic glass powder and fluorescent powder particles, or is a ceramic fluorescent layer obtained by sintering ceramic powder particles and fluorescent powder particles.

2. The wavelength conversion device according to claim 1, characterized in that: The silver powder includes a first silver powder and a second silver powder, the first silver powder has a median diameter of 0.5-5 μm, and the second silver powder has a median diameter of 20-200 nm.

3. The wavelength conversion device according to claim 2, characterized in that: The combined specific surface area of ​​the first silver powder and the second silver powder is 1-2 m 2 / g, and the full melting temperature of the glass powder is 700-800°C.

4. The wavelength conversion device according to claim 1, characterized in that: The mass ratio of silver powder to glass powder in the high-temperature sintered silver reflective layer is (97-99.5):(0.5-3).

5. The wavelength conversion device according to claim 1, characterized in that: The active metal transition layer is a titanium layer, a nickel layer, or a chromium layer.

6. The wavelength conversion device according to claim 1, characterized in that: The wavelength conversion layer is a glass fluorescent layer made by sintering inorganic glass powder and fluorescent powder particles. The glass sintered layer is a sintered layer of low-refractive index glass powder. The low-refractive index glass powder is a powder of inorganic glass powder whose refractive index is not higher than that of the glass fluorescent layer.

7. The wavelength conversion device according to claim 6, characterized in that: The linear expansion coefficient of the inorganic glass powder in the wavelength conversion layer is between that of the phosphor particles and the heat sink substrate, and the linear expansion coefficient of the glass powder of the high-temperature sintered silver reflective layer is higher than that of the heat sink substrate and lower than that of the silver powder.

8. The wavelength conversion device according to any one of claims 1 to 7, characterized in that: The thickness of the wavelength conversion layer is 40-120 μm; and / or the thickness of the glass sintered layer is 1-2 μm; and / or the thickness of the high-temperature sintered silver reflective layer is 10-30 μm; and / or the thickness of the active metal transition layer is 100-500 nm; and / or the thickness of the heat sink substrate is 0.5-3 mm.

9. The method for preparing the wavelength conversion device according to any one of claims 1 to 8, characterized in that: The steps include: (1) coating the surface of the heat sink substrate with an active metal transition layer: coating the surface of the heat sink substrate with an active metal transition layer by magnetron sputtering or evaporation; (2) preparing a sintered silver reflective layer slurry: adding silver powder and glass powder into a mortar, adding an organic solvent, grinding and stirring evenly, and then placing the mixture in a planetary mixer for stirring and removing bubbles to obtain a uniformly dispersed sintered silver reflective layer slurry; (3) The side of the heat sink substrate covered with the active metal transition layer is covered with a high-temperature sintered silver reflective layer: the sintered silver reflective layer slurry in step (2) is coated on the side of the heat sink substrate covered with the active metal transition layer by screen printing or steel screen printing, and then dried and sintered, so that the sintered silver reflective layer is firmly bonded to the surface of the heat sink substrate and the density of the sintered silver reflective layer is above 98%; (4) preparing a glass sintering layer slurry: adding an organic solvent to the low-refractive index glass powder, stirring evenly, and then transferring to a planetary mixer for stirring and removing bubbles, so that the low-refractive index glass powder is evenly dispersed to obtain a glass sintering layer slurry; (5) Covering the surface of the high-temperature sintered silver reflective layer with a glass sintered layer: using a screen printing process, a layer of glass sintered layer slurry is coated on the surface of the high-temperature sintered silver reflective layer, and the coating length and / or width of the glass sintered layer slurry is controlled so that the glass sintered layer slurry wraps the high-temperature sintered silver reflective layer, and then baked in an oven to obtain a dry film of the glass sintered layer, and then the heat sink substrate covered with the dry film of the glass sintered layer is placed in a sintering furnace for sintering, so that the glass sintered layer is bonded to the surface of the high-temperature sintered silver reflective layer, and together with the active metal transition layer, the glass sintered layer wraps the high-temperature sintered silver reflective layer; (6) preparing fluorescent glass slurry: adding fluorescent powder particles and inorganic glass powder particles into a mortar, adding an organic solvent, grinding and stirring, and then placing in a planetary mixer to stir and remove bubbles, to obtain a uniformly dispersed glass fluorescent slurry; (7) Covering the surface of the glass sintered layer with a glass fluorescent layer: using a screen printing process, covering the surface of the glass sintered layer with a layer of glass fluorescent slurry, and controlling the coating length and / or width of the glass fluorescent slurry so that the glass fluorescent wet film wraps the glass sintered layer; Subsequently, the glass fluorescent wet film is baked in an oven to obtain a glass fluorescent dry film, which is then sintered so that the glass fluorescent layer is firmly bonded to the surface of the heat sink substrate to obtain a wavelength conversion device.

10. The method for preparing the wavelength conversion device according to any one of claims 1 to 5 and 8, characterized in that: The steps include: S1. Coating a layer of active metal transition layer on the surface of the heat sink substrate: coating a layer of active metal transition layer on the surface of the heat sink substrate by magnetron sputtering or evaporation; S2. Prepare sintered silver reflective layer slurry: add silver powder and glass powder into a mortar, add an organic solvent, grind and stir evenly, place in a planetary mixer and stir to remove bubbles, so as to obtain a uniformly dispersed sintered silver reflective layer slurry; S3, the side of the heat sink substrate surface covered with the active metal transition layer is covered with a high-temperature sintered silver reflective layer: the sintered silver reflective layer slurry in step S2 is coated on the side of the heat sink substrate covered with the active metal transition layer by screen printing or steel screen printing process, and dried and sintered, so that the sintered silver reflective layer is firmly bonded to the surface of the heat sink substrate and the density of the sintered silver reflective layer is above 98%; S4, preparing glass sintering layer slurry: adding an organic solvent to the low-refractive index glass powder, stirring evenly, and then transferring to a planetary mixer for stirring and removing bubbles, so that the low-refractive index glass powder is evenly dispersed to obtain glass sintering layer slurry; S5. Covering the surface of the high-temperature sintered silver reflective layer with a glass sintered layer: covering the surface of the high-temperature sintered silver reflective layer with a layer of glass sintered layer slurry, and controlling the coating length and / or width of the glass sintered layer slurry so that the glass sintered layer slurry wraps the high-temperature sintered silver reflective layer, and a glass sintered layer wet film is formed on the surface; S6. Preparation of fluorescent ceramics: adding ceramic powder particles and fluorescent powder particles into a ball mill, adding an organic solvent as a ball milling medium, and mixing the materials uniformly to obtain fluorescent ceramic slurry; placing the fluorescent ceramic slurry in an oven to dry, and then grinding and crushing to obtain fluorescent ceramic dry powder, using SPS sintering technology to obtain fluorescent ceramic block materials, and then slicing, grinding and polishing to obtain ceramic fluorescent sheets; S7. Covering the surface of the glass sintered layer with a ceramic fluorescent layer: placing the ceramic fluorescent sheet prepared in step S6 on the surface of the wet film of the glass sintered layer, and then baking it in an oven to obtain a dry film of the glass sintered layer, and then placing the dry film of the glass sintered layer with the ceramic fluorescent sheet attached to the surface into a sintering furnace for sintering, so that the fluorescent ceramic sheet is firmly bonded to the surface of the heat sink substrate by the glass sintered layer, thereby obtaining a wavelength conversion device.

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