A lens-type fluorescent composite ceramic for laser illumination and its preparation method

Abstract

This invention discloses a lens-type fluorescent composite ceramic for laser illumination and its preparation method, comprising a YAG ceramic lens and a fluorescent ceramic block disposed at the central focal point inside the YAG ceramic lens. The chemical formula of the fluorescent ceramic block is (Re). 1‑x Ce x )3Al5O 12 In the formula, Re represents one or more elements from Y, Lu, Ga, Gd, and Tb, where 0.0001 ≤ x ≤ 0.005. Preparation method: Fluorescent ceramic blocks are prepared using a dry pressing method; a gel casting slurry is prepared using YAG ceramic lens powder as raw material. The fluorescent ceramic block is then coated onto the central focal point of the YAG ceramic lens using a double gel casting process. The fluorescent composite ceramic is obtained through drying, debinding, sintering, annealing, and polishing. This method effectively improves luminous efficiency and heat dissipation capacity while flexibly controlling the light divergence angle. The prepared fluorescent composite ceramic achieves high lumen efficiency and high brightness luminous performance, making it suitable for long-term stable lighting in various fields.

Description

Technical Field

[0001] This invention relates to the field of laser lighting technology, specifically to a lens-type fluorescent composite ceramic for laser lighting and its preparation method. Background Technology

[0002] Fluorescent ceramics have become the best-performing and most promising fluorescent materials for high-power solid-state lighting due to their high thermal stability and conductivity, high quantum efficiency, and easily tunable microstructure. Typically, fluorescent ceramics paired with LED chips emit light in a 360° arc, and the emitted light approximates Lambertian light, but with a large divergence angle, making it difficult to obtain a well-collimated illumination beam. Therefore, current LED-excited fluorescent ceramics suffer from the problem of a large divergence angle.

[0003] White laser lighting is the next generation of lighting technology following white LED lighting, boasting significant advantages such as environmental friendliness, energy saving, high luminous efficacy, high efficiency, and small size. Compared to LEDs, LDs are not only more efficient, brighter, and have a longer illumination distance, but they also overcome the inherent "efficiency degradation" problem of LEDs at high power, making them promising for applications in automotive headlights, outdoor lighting, laser cinemas, and other fields.

[0004] Because laser light sources have advantages such as concentrated energy and good collimation, they can form high-energy-density point light sources. Therefore, with certain optical designs, laser lighting fixtures with very small beam divergence angles can be designed. At the same power, their illumination distance is much greater than that of xenon lamps and LED lamps, which is very advantageous for long-distance lighting applications. However, the power density of blue light that fluorescent ceramic sheets can withstand is very limited. Excessive power density can cause thermal quenching or even burnout of the fluorescent ceramic sheets. Therefore, heat dissipation is still an issue for LD-excited fluorescent ceramics.

[0005] CN207796611U discloses an optical structure for laser illumination, which employs a conical light-shielding tube. Its optical path is complex, and the collimation path design is difficult. Therefore, it is not the best choice in terms of cost and difficulty when applied to general lighting. CN218721037U discloses a 360-degree laser illumination structure, in which a first cylindrical mirror, a second cylindrical mirror, and a right-angle prism are arranged sequentially in the laser beam incident direction. The right-angle prism can rotate along the axis to achieve 360-degree laser illumination. Although this device can achieve omnidirectional illumination, the optical design is complex, there are many optical components, and there is a lot of light loss.

[0006] Therefore, in view of the above problems, it is necessary to propose a technical solution that has a simple optical path design, does not require secondary optical path design, can reduce the light divergence angle, and can achieve stable operation of fluorescent materials. Summary of the Invention

[0007] The purpose of this invention is to provide a lens-type fluorescent composite ceramic for laser lighting and its preparation method. This method can reduce light scattering, effectively improve luminous efficiency and heat dissipation capacity, and flexibly control the light divergence angle. The prepared lens-type fluorescent composite ceramic can achieve high lumen efficiency and high brightness luminous performance, and can be used for long-term stable lighting in different fields.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a lens-type fluorescent composite ceramic for laser illumination, wherein the fluorescent composite ceramic is composed of a fluorescent ceramic block and a YAG ceramic lens, the fluorescent ceramic block being disposed at the central focal point inside the YAG ceramic lens, and the chemical formula of the fluorescent ceramic block (Re...) 1-x Ce x )3Al5O 12 In the formula, Re is one or more of the elements Y, Lu, Ga, Gd, and Tb, and x is the value of Re. 3+ Replace Ce 3+ The percentage of moles in a given position, 0.0001≤x≤0.005.

[0009] Preferably, the fluorescent ceramic block is a cube with a side length of 1-2 mm and a linear transmittance of 10-30% at 800 nm; the YAG ceramic lens has a bottom diameter of 5-10 mm, a surface curvature of 0.2-0.4, and a focal length of 6-10 mm.

[0010] This invention also provides a method for preparing the above-mentioned lens-type fluorescent composite ceramic for laser illumination, the specific steps of which are as follows:

[0011] S1. Millimeter-scale fluorescent ceramic blocks were prepared using the dry pressing method.

[0012] S1-1, Using Re₂O₃, Ce₂O₃, and Al₂O₃ as raw material powders, according to the chemical formula (Re 1-x Ce x )3Al5O 12 Weigh each raw material according to the stoichiometric ratio of the corresponding elements, where Re is one or more of Y, Lu, Ga, Gd, and Tb, and x is the stoichiometric ratio of Re. 3+ Replace Ce 3 + The percentage of moles in a given position, 0.0001 ≤ x ≤ 0.005;

[0013] S1-2. After mixing the above raw materials, add sintering aid, dispersant, anhydrous ethanol, and Al2O3 grinding balls, and then sequentially perform ball milling, drying, sieving, and calcination to obtain (Re). 1-x Ce x )3Al5O 12 Fluorescent ceramic block powder;

[0014] S1-3, Dry-press the fluorescent ceramic block powder to... Fluorescent ceramic blanks are formed in the mold;

[0015] S1-4. The fluorescent ceramic block blank is vacuum sintered and annealed, then cut and polished to obtain an area of ​​1.0–4.0 mm². 2 Fluorescent ceramic blocks with a thickness of 1-2 mm;

[0016] S2, Press Y3Al5O 12 The raw material powders Y2O3 and Al2O3 were weighed according to the stoichiometric ratio, and dispersant, sintering aid, anhydrous ethanol and Al2O3 grinding balls were added. The powders were then ball-milled, dried, sieved and calcined to obtain YAG ceramic lens powder.

[0017] S3. Add dispersant, pH adjuster, monomer acrylamide, crosslinking agent, pure water and Al2O3 grinding ball to the YAG ceramic lens powder prepared in step S2. After ball milling, filter out the slurry, remove bubbles under vacuum, add initiator, and mix evenly to obtain gel casting slurry.

[0018] S4. Pour part of the gel casting slurry prepared in S3 into a customized lens mold for one injection and solidification. The injection height is consistent with the focal length of the lens. Thermal initiation is carried out at 50-80℃ to solidify and form the shape.

[0019] S5. Wait for the lens layer in step S4 to gel for 1-2 hours to obtain the preliminary gel preform. Then, place the millimeter-sized fluorescent ceramic block prepared in step S1 in the center of the preliminary gel preform. Finally, pour the remaining gel casting slurry prepared in S3 into the mold for secondary casting and solidification to obtain the preform.

[0020] S6. After drying the green body in a constant temperature and humidity chamber, place it in a muffle furnace to remove the binder and obtain a composite ceramic green body.

[0021] S7. The composite ceramic blank is placed in a vacuum sintering furnace to obtain composite fluorescent ceramic, which is then air annealed in a muffle furnace. Finally, the ceramic surface and bottom surface are polished to obtain lens-type fluorescent composite ceramic.

[0022] Preferably, in steps S1-2 and S2, the sintering aid is MgO and TEOS, and the amount added is 0.1-0.6 wt.% and 0.3-0.5 wt.% of the total mass of the raw material powder, respectively; the dispersant is PEI, and the amount added is 0.1-0.5 wt.% of the total mass of the raw material powder.

[0023] Preferably, in steps S1-2 and S2, the ball milling speed is 160-220 r / min, the ball milling time is 10-24 h; the drying temperature is 50-80℃, the drying time is 6-24 h; the sieve mesh size is 80-300 mesh; and the calcination temperature is 800-1000℃, the calcination time is 8-16 h.

[0024] Preferably, in steps S1-3, the tableting pressure is 50-200 MPa and the holding time is 20-30 min;

[0025] Preferably, in steps S1-4, the vacuum sintering temperature is 1750-1800℃ and the sintering time is 8-12h; the annealing temperature is 1400-1450℃ and the annealing time is 8-16h.

[0026] Preferably, in step S3, the dispersant is ammonium citrate, added at 0.25–0.5 wt% of the YAG ceramic lens powder; the pH adjuster is tetramethylammonium hydroxide, added at 1–1.5 wt% of the YAG ceramic lens powder; the monomeric acrylamide is added at 2–3 wt% of the YAG ceramic lens powder; the crosslinking agent is N-N'-methylenebisacrylamide, added at 0.2–0.3 wt% of the YAG ceramic lens powder; the initiator is ammonium persulfate, added at 0.02–0.1 wt% of the YAG ceramic lens powder; the ball milling speed is 140–200 r / min, the ball milling time is 8–12 h; and the solid content of the slurry filtered after ball milling is 40–60 vol.%.

[0027] Preferably, in step S6, the drying temperature is 25-60℃, the drying humidity is 30%-80%, and the drying time is 12-36h; the glue discharge temperature is 600-900℃, and the glue discharge time is 24-72h.

[0028] Preferably, in step S7, the vacuum sintering temperature is 1750–1800℃, and the holding time is 8–30h; the annealing temperature is 1400–1450℃, and the annealing time is 8–16h.

[0029] Compared with existing technical solutions, the present invention has the following advantages:

[0030] (1) In this invention, the fluorescent ceramic block is designed in a millimeter-scale cubic shape. Its light-emitting surface is small and its brightness is high. When it is wrapped inside the YAG ceramic lens, there will be no loss of light emitted from the side, thus achieving high-brightness illumination. Furthermore, the light extraction rate can be effectively improved and the light divergence angle can be flexibly controlled by adjusting the surface curvature of the YAG ceramic lens to suit different lighting applications, achieving high lumen efficiency and high-brightness light-emitting performance. At the same time, the millimeter-scale light-emitting surface is well matched with the laser spot size, resulting in a more superior lumen effect.

[0031] (2) The present invention uses a co-firing method to prepare composite fluorescent ceramics. The fluorescent ceramics have stronger adhesion to the YAG lens blank, and the overall heat dissipation capacity of the composite ceramics is improved by utilizing the coating advantage, making it more suitable for long-term stable lighting in different fields.

[0032] (3) The present invention uses a two-stage gel casting method to prepare irregularly shaped composite ceramics, which effectively controls the fine structure of the green blank and does not produce defects such as cracks and deformation. At the same time, it can achieve mass production, which is conducive to the industrialization of the preparation of composite fluorescent ceramics. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the lens-type fluorescent composite ceramic of the present invention;

[0034] Appendix Figure 1 In the middle: 1. Fluorescent ceramic block, 2. YAG ceramic lens;

[0035] Figure 2 This is a physical image of the lens-type fluorescent composite ceramic of the present invention. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Example 1

[0038] A lens-type fluorescent composite ceramic for laser illumination, with the following structure: Figure 1 As shown, the fluorescent composite ceramic consists of a fluorescent ceramic block 1 and a YAG ceramic lens 2. The fluorescent ceramic block 1 is disposed at the central focal point inside the YAG ceramic lens 2. The chemical formula of the fluorescent ceramic block 1 is (YAG). 0.9999 Ce 0.0001 )3Al5O 12 .

[0039] The fluorescent ceramic block 1 is a cube with a side length of 1.414 mm and a linear transmittance of 30% at 800 nm; the YAG ceramic lens 2 has a bottom diameter of 15 mm, a surface curvature of 0.3, and a focal length of 6 mm.

[0040] The specific steps for preparing the above-mentioned lens-type fluorescent composite ceramic are as follows:

[0041] S1. Millimeter-scale fluorescent ceramic blocks were prepared using the dry pressing method.

[0042] S1-1, Using Y₂O₃, Ce₂O₃, and Al₂O₃ as raw material powders, according to the chemical formula (Y₂O₃, Ce₂O₃, and Al₂O₃), ... 0.9999 Ce 0.0001 )3Al5O 12 Weigh each raw material according to the stoichiometric ratio of the corresponding elements;

[0043] S1-2. After mixing the above raw materials, add sintering aid (0.1 wt% MgO and 0.3 wt% TEOS), dispersant (0.1 wt% PEI), anhydrous ethanol and Al2O3 grinding balls, and then sequentially ball mill, dry, sieve and calcinate to obtain (Y). 0.9999 Ce 0.0001 )3Al5O 12 Fluorescent ceramic block powder; ball milling speed 160 r / min, ball milling time 12 h; drying temperature 50℃, drying time 6 h; sieve mesh size 80 mesh; calcination temperature 800℃, calcination time 8 h;

[0044] S1-3, Dry-press the fluorescent ceramic block powder to... Fluorescent ceramic blanks are formed in the mold, with a pressing pressure of 100 MPa and a holding time of 20 min;

[0045] S1-4. The fluorescent ceramic block blank is vacuum sintered and annealed. The vacuum sintering temperature is 1750℃, and the sintering time is 8 hours. The annealing temperature is 1400℃, and the annealing time is 8 hours. Finally, it is cut and polished to obtain a blank with an area of ​​2.0 mm². 2 A fluorescent ceramic block with a thickness of 1 mm;

[0046] S2, Press Y3Al5O 12 Y2O3 and Al2O3 raw material powders were weighed according to the stoichiometric ratio. Dispersant (0.1 wt% PEI), sintering aid (0.1 wt% MgO and 0.3 wt% TEOS), anhydrous ethanol and Al2O3 grinding balls were added. The powders were then ball-milled, dried, sieved and calcined to obtain YAG ceramic lens powder. The ball milling speed was 160 r / min and the ball milling time was 12 h. The drying temperature was 50 ℃ and the drying time was 6 h. The sieve mesh size was 80 mesh. The calcination temperature was 800 ℃ and the calcination time was 8 h.

[0047] S3. Add 0.25wt% of dispersant ammonium citrate, 1wt% of pH adjuster tetramethylammonium hydroxide, 2wt% of monomer acrylamide, 0.2wt% of crosslinking agent N-N'-methylenebisacrylamide, pure water and Al2O3 grinding balls to the YAG ceramic lens powder prepared in step S2. After ball milling at 140 r / min for 8 h, filter out the slurry. The solid content of the slurry is 40 vol.%. After vacuum degassing, add 0.02wt% of initiator ammonium persulfate and mix evenly to obtain gel casting slurry.

[0048] S4. Pour part of the gel casting slurry prepared in S3 into a custom lens mold (designed focal length of 6mm, curvature of 0.3, and bottom diameter of 15mm) for one injection and solidification. The injection height is consistent with the focal length of the lens. Thermal initiation is carried out at 50℃ to solidify and form the shape.

[0049] S5. Wait 1 hour for the lens layer in step S4 to gel first to obtain the preliminary gel preform. Then place the millimeter-sized fluorescent ceramic block prepared in step S1 in the center of the preliminary gel preform. Finally, pour the remaining gel casting slurry prepared in S3 into the mold for secondary casting and solidification to obtain the preform.

[0050] S6. After drying the green body in a constant temperature and humidity chamber, place it in a muffle furnace to remove the binder and obtain a composite ceramic green body; the drying temperature is 60℃, the drying humidity is 80%, and the drying time is 12h; the binder removal temperature is 900℃ and the binder removal time is 24h.

[0051] S7. The composite ceramic blank is sintered in a vacuum sintering furnace to obtain composite fluorescent ceramic. The vacuum sintering temperature is 1750℃ and the holding time is 8 hours. Then, it is air annealed in a muffle furnace at 1400℃ for 8 hours. Finally, the ceramic surface and bottom surface are polished to obtain lens-shaped fluorescent composite ceramic. See the actual picture. Figure 2 .

[0052] The lens-type fluorescent composite ceramic was excited by a blue laser. When the blue light output power was 10W, the fluorescent ceramic device exhibited stable luminescence, operating at 80℃ with a luminous efficiency of 120 lm / W, a luminous flux of up to 1200 lm, and a luminous density of 1529 lm / mm². 2 The light divergence angle is 10°.

[0053] Example 2

[0054] A lens-type fluorescent composite ceramic for laser illumination, with the following structure: Figure 1 As shown, the fluorescent composite ceramic consists of a fluorescent ceramic block 1 and a YAG ceramic lens 2. The fluorescent ceramic block 1 is disposed at the central focal point inside the YAG ceramic lens 2. The chemical formula of the fluorescent ceramic block 1 is (Lu). 0.995 Ce 0.005 )3Al5O 12 .

[0055] The fluorescent ceramic block 1 is a cube with a side length of 1 mm and a linear transmittance of 20% at 800 nm; the YAG ceramic lens 2 has a bottom diameter of 15 mm, a surface curvature of 0.3, and a focal length of 6 mm.

[0056] The specific steps for preparing the above-mentioned lens-type fluorescent composite ceramic are as follows:

[0057] S1. Millimeter-scale fluorescent ceramic blocks were prepared using the dry pressing method.

[0058] S1-1, Using Lu2O3, Ce2O3, and Al2O3 as raw material powders, according to the chemical formula (Lu 0.995 Ce 0.005 )3Al5O 12 Weigh each raw material according to the stoichiometric ratio of the corresponding elements;

[0059] S1-2. After mixing the above raw materials, add sintering aid (0.6 wt% MgO and 0.5 wt% TEOS), dispersant (0.5 wt% PEI), anhydrous ethanol and Al2O3 grinding balls, and then sequentially ball mill, dry, sieve and calcinate to obtain (Lu 0.995 Ce 0.005 )3Al5O 12 Fluorescent ceramic block powder; ball milling speed 220 r / min, ball milling time 24 h; drying temperature 80℃, drying time 24 h; sieve mesh size 300 mesh; calcination temperature 1000℃, calcination time 10 h.

[0060] S1-3, Dry-press the fluorescent ceramic block powder to... Fluorescent ceramic blanks are formed in the mold; the pressing pressure is 200MPa and the holding time is 30min;

[0061] S1-4. The fluorescent ceramic block blank is vacuum sintered and annealed. The vacuum sintering temperature is 1800℃ and the sintering time is 10h. The annealing temperature is 1450℃ and the annealing time is 10h. Finally, it is cut and polished to obtain a blank with an area of ​​1.0mm². 2 A fluorescent ceramic block with a thickness of 1 mm;

[0062] S2, Press Y3Al5O 12 Y2O3 and Al2O3 raw material powders were weighed according to the stoichiometric ratio. Dispersant (0.5wt% PEI), sintering aid (0.6wt% MgO and 0.5wt% TEOS), anhydrous ethanol and Al2O3 grinding balls were added. The powders were then ball-milled, dried, sieved and calcined to obtain YAG ceramic lens powder. The ball milling speed was 220 r / min and the ball milling time was 24 h. The drying temperature was 80℃ and the drying time was 24 h. The sieve mesh size was 300 mesh. The calcination temperature was 1000℃ and the calcination time was 10 h.

[0063] S3. Add 0.5wt% of dispersant ammonium citrate, 1.5wt% of pH adjuster tetramethylammonium hydroxide, 3wt% of monomer acrylamide, 0.3wt% of crosslinking agent N-N'-methylenebisacrylamide, pure water and Al2O3 grinding balls to the YAG ceramic lens powder prepared in step S2. After ball milling at 200 r / min for 12 h, filter out the slurry. The solid content of the slurry is 60 vol.%. After vacuum degassing, add 0.05wt% of initiator ammonium persulfate and mix evenly to obtain gel casting slurry.

[0064] S4. Pour part of the gel casting slurry prepared in S3 into a custom lens mold (designed focal length of 5mm, curvature of 0.2, and bottom diameter of 12mm) for one injection and solidification. The injection height is consistent with the focal length of the lens. Thermal initiation is carried out at 60℃ to solidify and form the shape.

[0065] S5. Wait 2 hours for the lens layer in step S4 to gel before obtaining the preliminary gel preform. Then place the millimeter-sized fluorescent ceramic block prepared in step S1 in the center of the preliminary gel preform. Finally, pour the remaining gel casting slurry prepared in S3 into the mold for secondary casting and solidification to obtain the preform.

[0066] S6. After drying the green body in a constant temperature and humidity chamber, place it in a muffle furnace to remove the binder and obtain a composite ceramic green body; the drying temperature is 50℃, the drying humidity is 30%, and the drying time is 24h; the binder removal temperature is 800℃ and the binder removal time is 72h.

[0067] S7. The composite ceramic blank is placed in a vacuum sintering furnace and sintered to obtain composite fluorescent ceramic. The vacuum sintering temperature is 1780℃ and the holding time is 10h. Then, it is air annealed in a muffle furnace at a temperature of 1450℃ for 10h. Finally, the ceramic surface and bottom surface are polished to obtain lens-type fluorescent composite ceramic.

[0068] The lens-type fluorescent composite ceramic was excited by a blue laser. When the blue light output power was 10W, the fluorescent ceramic device exhibited stable luminescence, operating at 75℃ with a luminous efficiency of 150 lm / W, a luminous flux of up to 1500 lm, and a luminous density of 746 lm / mm². 2 The light divergence angle is 15°.

[0069] Example 3

[0070] A lens-type fluorescent composite ceramic for laser illumination, with the following structure: Figure 1 As shown, the fluorescent composite ceramic consists of a fluorescent ceramic block 1 and a YAG ceramic lens 2. The fluorescent ceramic block 1 is disposed at the central focal point inside the YAG ceramic lens 2. The chemical formula of the fluorescent ceramic block 1 is (Gd... 0.9999 Ce 0.0001 )3Al5O 12 .

[0071] The fluorescent ceramic block 1 is a cube with a side length of 2mm and a linear transmittance of 10% at 800nm; the YAG ceramic lens 2 has a bottom diameter of 18mm, a surface curvature of 0.2, and a focal length of 10mm.

[0072] The specific steps for preparing the above-mentioned lens-type fluorescent composite ceramic are as follows:

[0073] S1. Millimeter-scale fluorescent ceramic blocks were prepared using the dry pressing method.

[0074] S1-1, Using Gd₂O₃, Ce₂O₃, and Al₂O₃ as raw material powders, according to the chemical formula (Gd₂O₃, Ce₂O₃, and Al₂O₃), ... 0.9999 Ce 0.0001 )3Al5O 12 Weigh each raw material according to the stoichiometric ratio of the corresponding elements;

[0075] S1-2. After mixing the above raw materials, add sintering aid (0.3wt% MgO and 0.4wt% TEOS), dispersant (0.1wt% PEI), anhydrous ethanol, and Al2O3 grinding balls. Then, sequentially ball mill, dry, sieve, and calcinate to obtain (Gd). 0.9999 Ce 0.0001 )3Al5O 12 Fluorescent ceramic block powder; ball milling speed 180 r / min, ball milling time 16 h; drying temperature 60℃, drying time 8 h; sieve mesh size 100 mesh; calcination temperature 800℃, calcination time 16 h.

[0076] S1-3, Dry-press the fluorescent ceramic block powder to... Fluorescent ceramic blanks are formed in the mold; the pressing pressure is 50 MPa and the holding time is 25 min;

[0077] S1-4. The fluorescent ceramic block blank is vacuum sintered and annealed. The vacuum sintering temperature is 1760℃, and the sintering time is 10 hours. The annealing temperature is 1400℃, and the annealing time is 16 hours. Finally, it is cut and polished to obtain a blank with an area of ​​2.0 mm². 2 A fluorescent ceramic block with a thickness of 1 mm;

[0078] S2, Press Y3Al5O 12Y2O3 and Al2O3 raw material powders were weighed according to the stoichiometric ratio. Dispersant (0.2wt% PEI), sintering aid (0.3wt% MgO and 0.2wt% TEOS), anhydrous ethanol and Al2O3 grinding balls were added. The powders were then ball-milled, dried, sieved and calcined to obtain YAG ceramic lens powder. The ball milling speed was 200 r / min and the ball milling time was 10 h. The drying temperature was 60℃ and the drying time was 8 h. The sieve mesh size was 200 mesh. The calcination temperature was 800℃ and the calcination time was 16 h.

[0079] S3. Add 0.35wt% of dispersant ammonium citrate, 1.5wt% of pH adjuster tetramethylammonium hydroxide, 2.5wt% of monomer acrylamide, 0.15wt% of crosslinking agent N-N'-methylenebisacrylamide, pure water and Al2O3 grinding balls to the YAG ceramic lens powder prepared in step S2. After ball milling at 200 r / min for 8 h, filter out the slurry. The solid content of the slurry is 55 vol.%. After vacuum degassing, add 0.1wt% of initiator ammonium persulfate and mix evenly to obtain gel casting slurry.

[0080] S4. Pour part of the gel casting slurry prepared in S3 into a custom lens mold (designed focal length of 10mm, curvature of 0.2, and bottom diameter of 18mm) for one injection and solidification. The injection height is consistent with the focal length of the lens. Thermal initiation is carried out at 60℃ to solidify and form the shape.

[0081] S5. Wait for the lens layer in step S4 to gel for 1.5 hours to obtain the preliminary gel preform. Then, place the millimeter-sized fluorescent ceramic block prepared in step S1 in the center of the preliminary gel preform. Finally, pour the remaining gel casting slurry prepared in step S3 into the mold for secondary casting and solidification to obtain the preform.

[0082] S6. After drying the green body in a constant temperature and humidity chamber, place it in a muffle furnace to remove the binder and obtain a composite ceramic green body; the drying temperature is 25℃, the drying humidity is 60%, and the drying time is 36h; the binder removal temperature is 600℃ and the binder removal time is 48h.

[0083] S7. The composite ceramic blank is placed in a vacuum sintering furnace and sintered to obtain composite fluorescent ceramic. The vacuum sintering temperature is 1800℃ and the holding time is 30h. Then, it is air annealed in a muffle furnace at a temperature of 1400℃ for 16h. Finally, the ceramic surface and bottom surface are polished to obtain lens-type fluorescent composite ceramic.

[0084] The composite fluorescent ceramic device, excited by blue laser light, exhibits stable luminescence at a blue light output power of 10W, operating at 85℃ with a luminous efficiency of 160 lm / W, a luminous flux of up to 1600 lm, and a luminous density of 850 lm / mm². 2 The light divergence angle is 18°.

[0085] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a lens-type fluorescent composite ceramic for laser illumination, characterized in that, The fluorescent composite ceramic consists of a fluorescent ceramic block (1) and a YAG ceramic lens (2). The fluorescent ceramic block (1) is located at the central focal point inside the YAG ceramic lens (2). The chemical formula of the fluorescent ceramic block (1) is Re. 1-x Ce x )3Al5O 12 In the formula, Re is one or more of the elements Y, Lu, Ga, Gd, and Tb. x For Re 3+ Replace Ce 3+ The percentage of moles in a given position, 0.0001≤ x ≤0.005; The specific steps of the preparation method are as follows: S1. Millimeter-scale fluorescent ceramic blocks were prepared using the dry pressing method. S1-1, Using Re₂O₃, Ce₂O₃, and Al₂O₃ as raw material powders, according to the chemical formula (Re 1-x Ce x )3Al5O 12 Weigh each raw material according to the stoichiometric ratio of the corresponding elements, where Re is one or more of the elements Y, Lu, Ga, Gd, and Tb. x For Re 3+ Replace Ce 3+ The percentage of moles in a given position, 0.0001≤ x ≤0.005; S1-2. After mixing the above raw materials, add sintering aid, dispersant, anhydrous ethanol, and Al2O3 grinding balls. Then, sequentially perform ball milling, drying, sieving, and calcination to obtain (Re). 1-x Ce x )3Al5O 12 Fluorescent ceramic block powder; S1-3. The fluorescent ceramic block powder is dry-pressed into a φ20 mm mold to form a fluorescent ceramic block blank; S1-4. The fluorescent ceramic block blank is vacuum sintered and annealed, then cut and polished to obtain an area of ​​1.0–4.0 mm². 2 Fluorescent ceramic blocks with a thickness of 1–2 mm; S2, Press Y3Al5O 12 The raw material powders Y2O3 and Al2O3 were weighed according to the stoichiometric ratio, and dispersant, sintering aid, anhydrous ethanol and Al2O3 grinding balls were added. The powders were then ball-milled, dried, sieved and calcined to obtain YAG ceramic lens powder. S3. Add dispersant, pH adjuster, monomer acrylamide, crosslinking agent, pure water and Al2O3 grinding ball to the YAG ceramic lens powder prepared in step S2. After ball milling, filter out the slurry, remove bubbles under vacuum, add initiator, and mix evenly to obtain gel casting slurry. S4. Pour part of the gel casting slurry prepared in S3 into a custom lens mold for one injection and solidification. The injection height is consistent with the focal length of the lens. Thermal initiation is carried out at 50-80 ℃, and solidification is performed. S5. Wait for the lens layer in step S4 to gel for 1-2 hours to obtain the preliminary gel preform. Then, place the millimeter-sized fluorescent ceramic block prepared in step S1 in the center of the preliminary gel preform. Finally, pour the remaining gel casting slurry prepared in S3 into the mold for secondary casting and solidification to obtain the preform. S6. After drying the green body in a constant temperature and humidity chamber, place it in a muffle furnace to remove the binder and obtain a composite ceramic green body. S7. The composite ceramic blank is placed in a vacuum sintering furnace to obtain composite fluorescent ceramic, which is then air annealed in a muffle furnace. Finally, the ceramic surface and bottom surface are polished to obtain lens-type fluorescent composite ceramic.

2. The method for preparing a lens-type fluorescent composite ceramic for laser illumination according to claim 1, characterized in that, In steps S1-2 and S2, the sintering aids are MgO and TEOS, and the amounts added are 0.1-0.6 wt.% and 0.3-0.5 wt.% of the total mass of the raw material powder, respectively; the dispersant is PEI, and the amount added is 0.1-0.5 wt.% of the total mass of the raw material powder.

3. A method for preparing a lens-type fluorescent composite ceramic for laser illumination according to claim 1 or 2, characterized in that, In steps S1-2 and S2, the ball milling speed is 160-220 r / min, the ball milling time is 10-24 h; the drying temperature is 50-80 ℃, the drying time is 6-24 h; the sieve mesh size is 80-300 mesh; the calcination temperature is 800-1000 ℃, and the calcination time is 8-16 h.

4. A method for preparing a lens-type fluorescent composite ceramic for laser illumination according to claim 1 or 2, characterized in that, In steps S1-3, the tableting pressure is 50-200 MPa, and the holding time is 20-30 min.

5. A method for preparing a lens-type fluorescent composite ceramic for laser illumination according to claim 1 or 2, characterized in that, In steps S1-4, the vacuum sintering temperature is 1750~1800 ℃, and the sintering time is 8~12h; the annealing temperature is 1400~1450 ℃, and the annealing time is 8~16h.

6. A method for preparing a lens-type fluorescent composite ceramic for laser illumination according to claim 1 or 2, characterized in that, In step S3, the dispersant is ammonium citrate, added at 0.25–0.5 wt% of the YAG ceramic lens powder; the pH adjuster is tetramethylammonium hydroxide, added at 1–1.5 wt% of the YAG ceramic lens powder; the monomeric acrylamide is added at 2–3 wt% of the YAG ceramic lens powder; the crosslinking agent is N-N'-methylenebisacrylamide, added at 0.2–0.3 wt% of the YAG ceramic lens powder; the initiator is ammonium persulfate, added at 0.02–0.1 wt% of the YAG ceramic lens powder; the ball milling speed is 140–200 r / min, and the ball milling time is 8–12 h; the solid content of the slurry filtered after ball milling is 40–60 vol.%.

7. A method for preparing a lens-type fluorescent composite ceramic for laser illumination according to claim 1 or 2, characterized in that, In step S6, the drying temperature is 25–60 ℃, the drying humidity is 30%–80%, and the drying time is 12–36 h; the glue discharge temperature is 600–900 ℃, and the glue discharge time is 24–72 h.

8. A method for preparing a lens-type fluorescent composite ceramic for laser illumination according to claim 1 or 2, characterized in that, In step S7, the vacuum sintering temperature is 1750–1800 ℃, and the holding time is 8–30 h; the annealing temperature is 1400–1450 ℃, and the annealing time is 8–16 h.

9. The method for preparing a lens-type fluorescent composite ceramic for laser illumination according to claim 1, characterized in that, The fluorescent ceramic block (1) is a cube with a side length of 1 to 2 mm and a linear transmittance of 10 to 30% at 800 nm; the YAG ceramic lens (2) has a bottom diameter of 5 to 10 mm, a surface curvature of 0.2 to 0.4, and a focal length of 6 to 10 mm.

Images