Reflective fluorescent glass converter with heat dissipation through hole and preparation method and application thereof

Abstract

This invention relates to a reflective fluorescent glass transducer with heat dissipation through-holes, its preparation method, and its applications. The reflective fluorescent glass transducer comprises a heat dissipation substrate (4), a reflective layer (3), a fluorescent glass layer (2), and a scattering layer (1) stacked layer by layer. A through-hole array is provided on the heat dissipation substrate (4), and each heat dissipation through-hole (5) is filled with a highly thermally conductive metal. Through the heat dissipation through-hole array and the filling with highly thermally conductive metal, the heat dissipation performance of the fluorescent glass layer (2) is effectively improved. Combined with the scattering layer (1) covering its surface to assist in heat conduction and dissipation, the problem of heat deposition easily occurring on the outer surface of the reflective fluorescent glass transducer far from the heat dissipation substrate (4) under high power conditions due to the single-sided heat dissipation structure is completely solved. This reflective fluorescent glass transducer has advantages such as a high luminous saturation threshold and high light extraction, and can be applied to many fields such as high-power laser lighting and laser displays.

Description

Technical Field

[0001] This invention relates to the field of laser lighting or laser display technology, specifically to a reflective fluorescent glass converter with heat dissipation holes, its preparation method, and its application. Background Technology

[0002] Laser illumination technology, with its high output power, excellent brightness, long-distance projection capability, and good beam collimation characteristics, has been widely applied in various high-tech fields such as aerospace, medical equipment, and optical communication. Currently, common laser illumination devices on the market typically consist of a laser emitting element and a fluorescent conversion material, the latter primarily used to convert the excitation laser into white laser light for output. Under high-power laser excitation conditions, significant heat accumulation occurs inside the laser illumination device. If the heat dissipation path is inadequate or the heat dissipation efficiency is insufficient, not only will the light conversion efficiency decrease significantly, but it may also lead to thermal failure of the device. Furthermore, traditional fluorescent conversion materials are mostly organic fluorescent resins, which suffer from poor heat resistance and low thermal conductivity, making them unable to withstand continuous excitation by high-power-density lasers. They are also prone to material degradation phenomena such as thermal corrosion and carbonization, limiting their reliable application in high-power scenarios.

[0003] Fluorescent glass, an inorganic composite material composed of a glass matrix and dispersed phosphors, possesses a series of advantages, including good thermal stability, flexible and adjustable optical parameters, simple fabrication process, and relatively low cost. Despite its excellent properties in many aspects, fluorescent glass still exhibits certain defects and shortcomings, primarily including poor thermal conductivity and localized heat accumulation under high-power laser excitation conditions. Furthermore, in traditional single-sided heat dissipation structures (such as ceramic substrate solutions), heat is difficult to dissipate uniformly under high-power conditions, typically forming heat accumulation on the outer surface region far from the heat dissipation interface. This fails to meet the stringent requirements of high-power laser illumination for efficient thermal management, adversely affecting the luminous intensity and long-term thermal stability of white laser sources.

[0004] In summary, under current technological conditions, there is an urgent need to develop and design a novel fluorescence conversion structure to ensure that it can significantly improve light conversion efficiency and overall heat dissipation performance under high-power laser excitation, while also enhancing the working stability and lifespan of fluorescent materials. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides a reflective fluorescent glass converter with heat dissipation through-holes. By setting an array of heat dissipation through-holes on a heat dissipation substrate and electroplating them with thermally conductive metal, heat is rapidly dissipated from the fluorescent region, avoiding light decay and material degradation caused by localized high temperatures, and effectively improving the heat dissipation performance of the fluorescent glass layer. Simultaneously, the scattering layer covering the surface of the fluorescent glass layer also serves both as a heat conductor and a heat dissipator, jointly solving the problem of heat deposition on the outer surface far from the heat dissipation substrate in traditional single-sided heat dissipation structures under high power conditions. This meets the comprehensive requirements of current high-power laser lighting and next-generation laser display systems in terms of brightness, reliability, and thermal management.

[0006] As a complementary component, this invention uses a conductive silver paste material with high reflectivity in the 430nm-480nm wavelength range to prepare the reflective layer, effectively improving the luminous brightness of the laser source (especially the white laser source). The reflective fluorescent glass converter provided by this invention does not use organic bonding materials, avoiding problems such as failure and carbonization that are prone to occur under high-power laser excitation and high-temperature conditions, significantly improving the long-term reliability and service life of the device.

[0007] To achieve the aforementioned multiple objectives, the reflective fluorescent glass transducer with heat dissipation vias provided by this invention has a composite structure of at least four layers, including a heat dissipation substrate, a reflective layer, a fluorescent glass layer, and a scattering layer stacked layer by layer. At least one heat dissipation via penetrating only the heat dissipation substrate is provided on the heat dissipation substrate, and the via is filled with a thermally conductive metal material, such as copper. Copper has good thermal conductivity and is filled into the heat dissipation via through electroplating. Since the heat dissipation via vertically penetrates the heat dissipation substrate, the filled thermally conductive metal directly contacts the reflective layer for heat conduction, significantly enhancing the heat dissipation effect.

[0008] In the above scheme, when the number of layers of the reflective fluorescent glass converter is greater than four, the remaining layers are attached to the surface of the scattering layer in sequence.

[0009] In the above scheme, the reflective fluorescent glass converter has only four layers, which are, from bottom to top, a heat dissipation substrate, a reflective layer, a fluorescent glass layer, and a scattering layer. The heat dissipation substrate and the scattering layer are both outer layers, and the fluorescent glass layer and the reflective layer are both middle layers.

[0010] In the above scheme, the reflective layer partially or completely covers the surface of the heat dissipation substrate, preferably completely; the fluorescent glass layer partially or completely covers the surface of the reflective layer, preferably completely; and the scattering layer partially or completely covers the surface of the fluorescent glass layer, preferably completely. For each preferred scheme, this means that the heat dissipation substrate, the reflective fluorescent glass layer, and the scattering layer all have the same shape and area.

[0011] In the above scheme, multiple (≥3, the specific number can also be 9, 12, 16, etc.) heat dissipation through holes are provided on the surface of the heat dissipation substrate. The heat dissipation through holes are distributed on the surface of the heat dissipation substrate, thereby forming a heat dissipation through hole array.

[0012] In the above scheme, the heat dissipation holes can be evenly distributed on the entire surface of the heat dissipation substrate, or they can be concentrated in the center or central area of ​​the heat dissipation substrate.

[0013] In the above scheme, the heat dissipation holes can be distributed in a multi-row, multi-column manner, or in a nested circular, triangular, or elliptical manner, that is, the heat dissipation holes are distributed on the sides of multiple concentric circular, triangular, or elliptical shapes of different sizes.

[0014] In the above scheme, the sizes of the heat dissipation holes are equal or unequal, preferably equal. In some embodiments, in order to achieve better heat dissipation, the size of the heat dissipation holes in the center or central region of the heat dissipation substrate can be relatively larger, while the size of the heat dissipation holes in the edge region can be relatively smaller. Of course, the size of the heat dissipation holes in different locations can also be the same.

[0015] In the above scheme, the shape of the heat dissipation through hole is a regular closed shape such as a circle, ellipse, triangle, polygon, or other irregular closed shape.

[0016] In the above scheme, the heat dissipation substrate is selected from any one of aluminum nitride (AlN) ceramic, alumina (Al2O3) ceramic, boron nitride (BN) ceramic, metallic aluminum, and diamond, and its thermal conductivity is not less than 320W / m·K.

[0017] In the above scheme, the reflective layer is made of metallic silver, and its reflectivity in the 430nm-480nm band is not less than 90%.

[0018] In the above scheme, the fluorescent glass layer comprises phosphor and glass powder in a mass ratio of 0.3-2:1; the scattering layer comprises inorganic thermally conductive filler and glass powder in a mass ratio of 1:1-100. The phosphor is specifically a monochromatic or multicolor phosphor, such as YAG phosphor. The glass powder in the scattering layer and the fluorescent glass layer is specifically a low-temperature glass powder with a glass transition temperature not exceeding 700℃, such as Schott glass powder with the chemical composition 25B₂O₃-10SiO₂-35ZnO-6Li₂O-12La₂O₃-12WO₃ or 20Bi₂O₃-60B₂O₃-10ZnO-10BaO. The inorganic thermally conductive filler is selected from at least one of diamond powder, boron nitride powder, and alumina powder.

[0019] To ensure heat dissipation under high-power conditions, the thickness of the heat sink substrate is set to 0.3mm-3mm. To reduce optical losses caused by the substrate, the thickness of the reflective layer is set to 100μm-250μm, which is the maximum thickness among all functional layers. The corresponding thickness of the phosphor glass layer is set to 60μm-200μm. To ensure sufficient optical conditions for phosphor excitation, the thickness of the scattering layer is set to 20μm-40μm, which is the thinnest thickness among all functional layers. That is, the thickness order of each layer is: reflective layer > phosphor glass layer > scattering layer.

[0020] A second objective of this invention is to provide a method for fabricating the aforementioned reflective fluorescent glass converter with heat dissipation through-holes, the method comprising: S1. After coating the surface of the heat sink substrate with conductive silver paste and drying it, the reflective layer is formed by low-temperature sintering.

[0021] S2. After coating the reflective layer surface with fluorescent glass paste, dry it to form a fluorescent glass paste layer.

[0022] S3. After coating the surface of the fluorescent glass paste layer with a scattering paste and drying it, the two layers are then co-sintered to fuse and bond them together, thus forming a fluorescent glass layer and a scattering layer.

[0023] S4. Cover the front of the heat sink substrate with an insulating protective film to wrap the reflective layer, fluorescent glass layer and scattering layer, so as to protect each functional layer; use a laser to drill holes on the back of the heat sink substrate to form heat dissipation through holes that penetrate only the heat sink substrate.

[0024] S5. Use an electroplating process to electroplat a thermally conductive metal, such as copper, into the heat dissipation holes.

[0025] In the above scheme, the low-temperature sintering temperature in step S1 is 180℃-220℃, and the drying temperature is 120℃-150℃.

[0026] In the above scheme, the fluorescent glass paste in step S2 is composed of raw materials including phosphor, glass powder, and organic solvent. The selected phosphor and glass powder are as described above, and the selected organic solvent is at least one of turpentine percolate, ethanol, butyl carbitol acetate, and dibutyl phthalate. The drying temperature for this step is 120℃-150℃.

[0027] In the above scheme, the scattering slurry in step S3 is composed of inorganic thermally conductive filler, glass powder, and organic solvent, with the selection of glass powder and organic solvent being the same as in step S2. The drying temperature in this step is 120℃-150℃, the co-sintering temperature is 550℃-700℃, and the co-sintering time is 40min-90min. The fluorescent glass layer and the scattering layer are integrally formed through a high-temperature sintering process, effectively eliminating interlayer separation and porosity defects at the interface, and significantly improving the performance and structural reliability of the reflective fluorescent glass converter.

[0028] In the above scheme, the process parameters for electroplating the thermally conductive metal in step S5 are: electroplating additive working temperature of 0℃-85℃, and current density of 0.5A / dm. 2 -3A / dm 2 The electroplating rate is 30μm / h-200μm / h. The electroplating solution consists of: copper sulfate pentahydrate 150g / L-300g / L, sulfuric acid 30g / L-70g / L, sodium chloride 10mg / L-100mg / L, polyethylene glycol 150mg / L-500mg / L, and sodium thiazolinyl dithiopropane sulfonate 0.5mg / L-10mg / L. The stirring rate during the electroplating process is 100r / min-2000r / min.

[0029] In the above scheme, the coating method in steps S1, S2 and S3 is selected from any one of screen printing, spraying, blade coating, spin coating, dip-coating, and slot extrusion coating.

[0030] The third objective of this invention is to apply the aforementioned reflective fluorescent glass converter with heat dissipation holes to fields such as laser lighting and laser display, thereby realizing laser lighting and laser display by converting fluorescent light into white laser light source.

[0031] The reflective fluorescent glass converter provided by this invention operates by incident laser light from the upper surface of a heat-dissipating substrate. After passing through the scattering layer and reaching the fluorescent glass layer, the laser encounters inorganic phosphor particles, which excite fluorescence. The incident laser light is then reflected back after encountering the reflective layer, improving the fluorescence excitation effect. This reflective fluorescent glass converter comprises at least four layers, each with the following functions: the heat-dissipating substrate effectively dissipates heat generated under high-power laser excitation, ensuring the thermal stability and reliability of the reflective fluorescent glass converter during continuous operation; the reflective layer, in close contact with the fluorescent glass layer, not only efficiently conducts the heat generated under high-power laser excitation to the heat-dissipating substrate but also significantly reduces the absorption loss of photons by the substrate; the scattering layer, positioned between the air and the fluorescent glass layer, forms a physical separation structure, ensuring efficient heat conduction along the direction towards the heat-dissipating substrate. Furthermore, the inorganic thermally conductive filler in the scattering layer effectively scatters the incident light, thereby improving the uniformity of the emitted white light spot color. The heat dissipation vias effectively increase the saturation threshold of the reflective fluorescent glass converter, enabling it to meet the requirements of high-power laser excitation.

[0032] Compared with existing similar products or technologies, the beneficial effects of this invention are mainly reflected in the following aspects: (1) The reflective fluorescent glass converter prepared by this invention has a reflective structure. Through a heat dissipation substrate with an array of heat dissipation through-holes and a scattering layer that also has a thermal conductivity, bidirectional low thermal resistance heat dissipation of the fluorescent conversion element is achieved. By filling the heat dissipation through-holes with metallic copper, heat is quickly directed from the heat concentration area to the back of the heat dissipation substrate. Combined with a high thermal conductivity (≥320W / m·K) AlN substrate, the equivalent thermal resistance of the device and the temperature rise gradient of the fluorescent glass layer are significantly reduced. The diamond / BN scattering layer provides a lateral heat diffusion channel parallel to the light-emitting surface, realizing a bidirectional heat dissipation path. This effectively alleviates the heat accumulation on the side away from the heat dissipation substrate under high power excitation of the single-sided heat dissipation structure and the resulting failure risks such as warping, cracking, and delamination.

[0033] (2) The present invention preferably uses conductive silver paste and low-temperature sintering to form a reflective layer, which has high reflectivity in the 430nm-480nm wavelength band, and can send back the laser light that has not been absorbed in the first pass to the fluorescent glass layer for re-conversion. The scattering layer introduces multiple scattering and emission angle shaping, reduces the total internal reflection loss at the interface, improves the light extraction efficiency and emission uniformity, and finally obtains a high luminous saturation threshold (greater than 35W / mm). 2 A reflective fluorescent glass converter with high light extraction (luminous efficiency greater than 5500lm) is used, making it applicable to high laser saturation threshold fluorescence conversion white laser light sources, meeting the needs of high-power laser lighting and laser display.

[0034] (3) In this invention, copper is preferred as the heat-conducting medium for the heat dissipation through-holes. Compared with a single AlN substrate, the high thermal conductivity of copper (390W / m·K-400W / m·K) significantly improves the heat dissipation efficiency of the fluorescent glass layer. In addition, copper is easy to deposit in the through-holes through electroplating, which can form a continuous and dense metal layer, ensuring the uniformity and stability of the heat dissipation through-holes. The process is mature and has good controllability. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the reflective fluorescent glass converter with heat dissipation holes described in this invention.

[0036] Figure 2 This is an enlarged schematic diagram of the heat dissipation substrate containing a 3×3 heat dissipation through-hole array in this invention.

[0037] Figure 3 This is a process flow diagram of the fabrication process of the reflective fluorescent glass converter with heat dissipation holes described in this invention.

[0038] Figure description: 1-scattering layer, 2-fluorescent glass layer, 3-reflective layer, 4-heat dissipation substrate, 5-heat dissipation through hole, 6-PVC electroplating tape. Detailed Implementation

[0039] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments listed below are merely illustrative of the invention and do not constitute any limitation thereof. Furthermore, the technical features involved in the various embodiments described below can be combined with each other as long as they do not conflict with each other.

[0040] Unless otherwise stated, the descriptions of orientation or positional relationships in this invention, such as "upper," "lower," "left," "right," "front," and "rear," are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the purpose of facilitating the description of this invention and simplifying the description. They are not intended to indicate or imply that the system or component referred to must have a specific orientation or be constructed or operated in a specific orientation, and should not be construed as limiting the technical solution of this invention.

[0041] The structure of the reflective fluorescent glass converter with heat dissipation holes provided by this invention is as follows: Figure 1-2 As shown, from top to bottom, it includes a scattering layer 1, a fluorescent glass layer 2, a reflective layer 3, and a heat sink substrate 4. Multiple through-holes 5 are formed on the lower surface of the heat sink substrate 4, and the interior of the through-holes 5 is filled with metallic copper through electroplating. High-power (e.g., 5W and above) blue light excites yellow phosphor from the upper side of the heat sink substrate 4 to obtain white light for laser illumination or display.

[0042] The fabrication method of the reflective fluorescent glass converter with heat dissipation holes is as follows: Figure 3 As shown, the specific steps include: S1. Conductive silver paste is coated onto the upper surface of the heat sink substrate 4 by means of screen printing, etc., then dried at 120℃-150℃, then heated to 180-220℃ for low-temperature sintering, and after natural cooling, a reflective layer 3 is formed on the surface of the heat sink substrate 4.

[0043] S2. A fluorescent glass paste is prepared using phosphor, glass powder, and organic solvent as raw materials. The fluorescent glass paste is coated onto the surface of the reflective layer 3 by methods such as screen printing. Then, it is dried at 120℃-150℃ and naturally cooled to form a fluorescent glass paste layer on the surface of the reflective layer 3. The mass ratio of phosphor to glass powder in the paste is 0.3-2:1, and the phosphor is selected as a monochromatic (e.g., yellow) phosphor or a multicolor phosphor, while the glass powder is selected as a low-temperature glass powder with a glass transition temperature not exceeding 700℃.

[0044] S3. A scattering layer slurry is prepared using inorganic thermally conductive fillers such as diamond and BN, glass powder, and organic solvents as raw materials. The scattering layer slurry is coated onto the surface of the fluorescent glass slurry layer by means of screen printing, etc. Then, it is dried at 120℃-150℃, and then heated to 550℃-700℃ for sintering. After natural cooling, fluorescent glass layer 2 and scattering layer 1 are obtained simultaneously.

[0045] S4. PVC electroplated tape 6 is attached to the upper surface of the heat sink substrate 4, covering the reflective layer 3, the fluorescent glass layer 2, and the scattering layer 1. The heat sink substrate 4 is then inverted, and a laser is used to drill holes in the uncovered surface of the heat sink substrate 4, forming multiple heat dissipation through-holes 5 that penetrate only the heat sink substrate 4. These heat dissipation through-holes 5 are arranged in multiple rows and columns to form a heat dissipation through-hole array.

[0046] S5. Using an electroplating process, metallic copper is electroplated into the heat dissipation through-holes 5 of the heat dissipation substrate 4, thereby obtaining... Figure 1 The aforementioned reflective fluorescent glass converter.

[0047] Example 1 The first step is to prepare the reflective layer 3. An AlN ceramic substrate with a length and width of 15 mm and a thickness of 1 mm is selected as the heat dissipation substrate 4. Conductive silver paste is coated on the upper surface of the AlN ceramic substrate by screen printing. Then, it is heated to 120℃ and dried for 30 min. Then, it is heated to 200℃ for low-temperature sintering. After natural cooling, a reflective layer 3 with a thickness of about 0.1 mm is obtained.

[0048] The second step involves preparing the fluorescent glass paste layer. 0.6g of YAG phosphor, 0.4g of Schottky glass powder, and 0.32g of turpentine percolate are mixed evenly to obtain the fluorescent glass paste. The fluorescent glass paste is then screen-printed onto the surface of reflective layer 3, ensuring complete coverage. The layer is then heated to 120℃ and dried for 30 minutes to obtain a fluorescent glass paste layer with a thickness of approximately 0.15mm.

[0049] The Schott glass powder used in Example 1 of this invention has the following chemical composition: 25B₂O₃-10SiO₂-35ZnO-6Li₂O-12La₂O₃-12WO₃. The Arabic numerals preceding each component indicate the molar percentage of that component. Taking 25B₂O₃ as an example, it indicates that the molar percentage of B₂O₃ in the glass powder is 25%.

[0050] The third step involves preparing the scattering layer 1. 0.2g of diamond powder, 0.8g of Schottky glass powder (composition as in the previous step), and 0.32g of turpentine percolate are mixed evenly to obtain a diamond glass slurry. The diamond glass slurry is then coated onto the surface of the fluorescent glass slurry layer using a screen printing process. The mixture is then heated to 120℃ and dried for 30 minutes, followed by sintering at 700℃ for 90 minutes. After sintering, it is allowed to cool naturally to room temperature. During sintering, the diamond glass slurry melts and integrates with the fluorescent glass slurry layer, resulting in a fluorescent glass layer 2 with a thickness of approximately 0.15mm and a scattering layer 1 with a thickness of approximately 0.02mm.

[0051] Step 4: Laser drilling. The AlN ceramic substrate is completely covered with PVC electroplated tape 6, then inverted for laser drilling to obtain multiple heat dissipation through-holes 5 with a diameter of approximately 2mm. The drilling depth is strictly controlled to ensure complete penetration through the AlN ceramic substrate without damaging the reflective layer 3. After drilling, the result is as follows: Figure 2 The diagram shows a 3x3 array of heat dissipation through-holes.

[0052] Step 5: Electroplating copper into the heat dissipation through-hole 5. Electroplating process parameters: Electroplating additive manufacturing operating temperature 25℃, current density 1.5A / dm³. 2 The electroplating rate was 100 μm / h. The electroplating solution consisted of: copper sulfate pentahydrate 200 g / L, sulfuric acid 60 g / L, sodium chloride 50 mg / L, polyethylene glycol 300 mg / L, and sodium thiazolinyl dithiopropane sulfonate 6 mg / L. Mechanical stirring was performed during the electroplating process at a speed of 400 r / min to ensure a dense and uniform copper layer deposition inside the through-holes. After electroplating, the plating solution was removed, cleaned, and the desired result was obtained. Figure 1 The aforementioned reflective fluorescent glass converter with heat dissipation through-holes.

[0053] Comparative Example 1 This comparative example is basically the same as Example 1, except that the fifth step of copper electroplating was not performed. The resulting reflective fluorescent glass converter has empty heat dissipation holes 5, without any filling material.

[0054] Comparative Example 2 The first step is to prepare the reflective layer 3. An AlN ceramic substrate with a length and width of 15 mm and a thickness of 1 mm is selected as the heat dissipation substrate 4. Conductive silver paste is coated on the upper surface of the AlN ceramic substrate by screen printing. Then, it is heated to 120℃ and dried for 30 min. Then, it is heated to 200℃ for low-temperature sintering. After natural cooling, a reflective layer 3 with a thickness of about 0.1 mm is obtained.

[0055] The second step involves preparing the fluorescent glass paste layer. 0.6g of YAG phosphor, 0.4g of Schottky glass powder (from the same batch as in Example 1), and 0.32g of turpentine percolate are mixed evenly to obtain the fluorescent glass paste. The fluorescent glass paste is then screen-printed onto the surface of the reflective layer 3, completely covering it. The layer is then heated to 120°C and dried for 30 minutes to obtain a fluorescent glass paste layer with a thickness of approximately 0.15mm.

[0056] Comparative Example 2 shows a conventional reflective ceramic-based fluorescent converter.

[0057] Example 2 The first step is to prepare the reflective layer 3. An AlN ceramic substrate with a length and width of 20 mm and a thickness of 1 mm is selected as the heat dissipation substrate 4. Conductive silver paste is coated on the upper surface of the AlN ceramic substrate by screen printing. Then, it is heated to 120°C and dried for 30 min. Then, it is heated to 200°C for low-temperature sintering. After natural cooling, a reflective layer 3 with a thickness of about 0.15 mm is obtained.

[0058] The second step involves preparing the fluorescent glass paste layer. 0.6g of YAG phosphor, 0.5g of Schottky glass powder (chemical composition: 20Bi₂O₃-60B₂O₃-10ZnO-10BaO), and 0.48g of turpentine oil are mixed evenly to obtain the fluorescent glass paste. The fluorescent glass paste is then screen-printed onto the surface of reflective layer 3, completely covering it. The layer is then heated to 120℃ and dried for 30 minutes to obtain a fluorescent glass paste layer with a thickness of approximately 0.2mm.

[0059] The third step involves preparing the scattering layer 1. 0.01g of BN powder, 0.99g of Schottky glass powder (composition as in the previous step), and 0.32g of turpentine percolate are mixed evenly to obtain a BN glass paste. The BN glass paste is then coated onto the surface of the fluorescent glass paste layer using a screen printing process. The mixture is then heated to 120℃ and dried for 30 minutes, followed by sintering at 550℃ for 40 minutes. After sintering, it is allowed to cool naturally to room temperature. During sintering, the BN glass paste melts and integrates with the fluorescent glass paste layer, resulting in a fluorescent glass layer 2 with a thickness of approximately 0.2mm and a scattering layer 1 with a thickness of approximately 0.04mm.

[0060] The fourth step is laser drilling. The upper surface of the AlN ceramic substrate is completely covered with PVC electroplated tape 6, then inverted for laser drilling to obtain multiple 3mm diameter heat dissipation through-holes 5. The drilling depth is strictly controlled to ensure complete penetration through the AlN ceramic substrate without damaging the reflective layer 3. After drilling, a 4-row, 4-column array of heat dissipation through-holes is obtained.

[0061] Step 5: Copper plating of heat dissipation through-holes. Plating process parameters: Electroplating additive manufacturing operating temperature 25℃, current density 2A / dm³. 2 The electroplating rate was 100 μm / h. The electroplating solution consisted of: copper sulfate pentahydrate 180 g / L, sulfuric acid 40 g / L, sodium chloride 30 mg / L, polyethylene glycol 300 mg / L, and sodium thiazolinyl dithiopropane sulfonate 6 mg / L. Mechanical stirring was performed during the electroplating process at a speed of 500 r / min to ensure a dense and uniform copper layer deposition inside the through-holes. After electroplating, the plating solution was removed, cleaned, and the desired result was obtained. Figure 1 The aforementioned reflective fluorescent glass converter with heat dissipation through-holes.

[0062] Comparative Example 3 This comparative example is basically the same as Example 2, except that the fifth step of copper electroplating was not performed. The resulting reflective fluorescent glass converter has empty heat dissipation holes 5, without any filling material.

[0063] Comparative Example 4 The first step is to prepare the reflective layer 3. An AlN ceramic substrate with a length and width of 20 mm and a thickness of 1 mm is selected as the heat dissipation substrate 4. Conductive silver paste is coated on the upper surface of the AlN ceramic substrate by screen printing. Then, it is heated to 120°C and dried for 30 min. Then, it is heated to 200°C for low-temperature sintering. After natural cooling, a reflective layer 3 with a thickness of about 0.15 mm is obtained.

[0064] The second step involves preparing the fluorescent glass paste layer. 0.6g of YAG phosphor, 0.5g of Schottky glass powder (chemical composition: 20Bi₂O₃-60B₂O₃-10ZnO-10BaO), and 0.48g of turpentine percolate are mixed evenly to obtain the fluorescent glass paste. The fluorescent glass paste is then screen-printed onto the surface of reflective layer 3, completely covering it. The layer is then heated to 120℃ and dried for 30 minutes to obtain a fluorescent glass paste layer with a thickness of approximately 0.2mm.

[0065] Comparative Example 4 yielded a conventional reflective ceramic-based fluorescent converter.

[0066] To fully understand the performance of the reflective phosphor converters fabricated in each embodiment, the following tests were performed: The reflective fluorescence converters prepared in Examples 1 to 2 and Comparative Examples 1 to 4 were used as test samples. They were excited by a laser source with an output power of 5W, and their optical performance parameters in the excited state and surface temperature distribution in the working state were measured using an integrating sphere optical testing system and an infrared thermal imager, respectively. The specific test results are shown in the table below: Table 1. Comparison of test results for different samples

[0067] Comparing Example 1 and Comparative Example 1, it can be found that under the same power density laser excitation, the surface temperature rise of the sample in Comparative Example 1 is 20-30°C higher than that of the sample in Example 1, resulting in more severe local heat deposition. This leads to obvious thermal quenching and cracks in the fluorescent glass layer after long-term (8h) operation, while the fluorescent glass layer in Example 1 still functions normally. The same conclusion can be drawn by comparing the test results of Example 2 and Comparative Example 3.

[0068] Comparing Example 1 and Comparative Example 2, it can be found that under 5W laser irradiation, the luminous efficiency of the sample in Comparative Example 2 is only 150 lm / W, while the luminous efficiency of the sample in Example 1 is increased to 195 lm / W, an increase of up to 30%; the laser power saturation threshold also increased from 20W / mm² in Comparative Example 2. 2 Increased to 38W / mm in Example 1 2 The increase was as high as 90%; the corresponding luminous flux at the saturation threshold increased from 2005 lm in Comparative Example 2 to 5566 lm in Example 1, an increase of 178%.

[0069] Comparing Example 2 and Comparative Example 4, it can be found that under 5W laser irradiation, the luminous efficiency of the sample in Comparative Example 4 is only 165 lm / W, while the luminous efficiency of the sample in Example 2 is increased to 206 lm / W, an increase of up to 25%; the laser power saturation threshold also increased from 23W / mm² in Comparative Example 4. 2Increased to 42W / mm in Example 2 2 The increase was as high as 83%; the corresponding luminous flux at the saturation threshold increased from 2460 lm in Comparative Example 4 to 5983 lm in Example 2, an increase of 143%.

[0070] The comparison results above show that the reflective fluorescent glass converter with heat dissipation holes prepared according to the method of the present invention can fully meet the application requirements of high thermal conductivity and high light extraction laser illumination.

Claims

1. A method for fabricating a reflective fluorescent glass transducer with heat dissipation through-holes, characterized in that... The method includes: S1 uses any one of the following methods: screen printing, spraying, doctor blade coating, spin coating, dip-coating, or slot extrusion coating. After coating the surface of the heat dissipation substrate (4) with conductive silver paste, it is dried at 120℃-150℃ and then sintered at a low temperature of 180℃-220℃ to form a reflective layer (3). S2 uses any one of the following methods: screen printing, spraying, doctor blade coating, spin coating, dip-coating, or slot extrusion coating. After coating the reflective layer (3) with fluorescent glass paste, it is dried at 120℃-150℃ to form a fluorescent glass paste layer. S3 uses any one of the following methods: screen printing, spraying, doctor blade coating, spin coating, dip-coating, or slot extrusion coating. After coating the fluorescent glass paste layer with a scattering paste, it is dried at 120℃-150℃ and then co-sintered at 550℃-700℃ to form a fluorescent glass layer (2) and a scattering layer (1). S4 covers the surface of the heat sink substrate (4) with a protective film, which is used to wrap the reflective layer (3), the fluorescent glass layer (2) and the scattering layer (1). Then, holes are drilled on the other surface of the heat sink substrate (4) to form a heat dissipation through hole (5) that penetrates the heat sink substrate (4). S5 is filled with thermally conductive metal by electroplating in the heat dissipation through-hole (5). The specific process parameters are: the electroplating additive working temperature is 0℃-85℃, and the current density is 0.5A / dm. 2 -3A / dm 2 The electroplating rate is 30μm / h-200μm / h. The electroplating solution consists of: copper sulfate pentahydrate 150g / L-300g / L, sulfuric acid 30g / L-70g / L, sodium chloride 10mg / L-100mg / L, polyethylene glycol 150mg / L-500mg / L, sodium thiazolinyl dithiopropane sulfonate 0.5mg / L-10mg / L, and the stirring rate during the electroplating process is 100r / min-2000r / min. The thickness of the heat dissipation substrate (4) is 0.3mm-3mm, and its material is selected from any one of aluminum nitride ceramic, alumina ceramic, and boron nitride ceramic, and its thermal conductivity is not less than 320W / m·K; a plurality of heat dissipation through holes (5) are uniformly distributed on the surface of the heat dissipation substrate (4), the size of the heat dissipation through holes (5) is the same or different, and its shape is selected from at least one of circle, ellipse, triangle, and polygon, and the heat dissipation through holes (5) are filled with thermally conductive copper. The thickness of the reflective layer (3) is 100μm-250μm, and its material is metallic silver. Its reflectivity in the 430nm-480nm wavelength band is not less than 90%. The thickness of the fluorescent glass layer (2) is 60μm-200μm, and its composition includes phosphor and glass powder in a mass ratio of 0.3-2:

1. The scattering layer (1) has a thickness of 20μm-40μm and its composition includes inorganic thermally conductive filler and glass powder with a mass ratio of 1:1-100. All phosphors are either monochromatic or multicolor phosphors, all glass powders are low-temperature glass powders with a glass transition temperature not exceeding 700℃, and the inorganic thermally conductive fillers are selected from at least one of diamond powder and boron nitride powder.

2. The preparation method according to claim 1, characterized in that: The reflective fluorescent glass converter has only four layers: the reflective layer (3) partially or completely covers the surface of the heat dissipation substrate (4), the fluorescent glass layer (2) partially or completely covers the surface of the reflective layer (3), and the scattering layer (1) partially or completely covers the surface of the fluorescent glass layer (2).

3. The preparation method according to claim 1, characterized in that: The number of heat dissipation holes (5) is not less than 3.

4. The preparation method according to claim 1, characterized in that: The fluorescent glass paste in step S2 is composed of phosphor, glass powder and organic solvent. The scattering paste in step S3 is composed of inorganic thermally conductive filler, glass powder and organic solvent. The organic solvent is selected from at least one of turpentine percolate, ethanol, butyl carbitol acetate and dibutyl phthalate.

5. The application of the preparation method according to any one of claims 1-4 in laser lighting or laser display.

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