Composite structure fluorescent ceramic for regulating photothermal performance and preparation method and application thereof

Abstract

The application discloses a composite structure fluorescent ceramic for regulating photothermal performance and a preparation method and application thereof. The composite structure fluorescent ceramic is composed of a plurality of light emitting units, each of which is sequentially composed of an outer skin layer, a fluorescent body and a heat conduction rod, wherein the outer skin layer is circumferentially coated on the surface layer of the fluorescent body, and the heat conduction rod is circumferentially arranged in the fluorescent body. The composite structure ceramic blank is printed layer by layer through 3D printing combined with photocuring technology, and the composite structure ceramic is obtained after sintering. The total reflection effect caused by the difference in refractive index between the outer skin layer and the fluorescent body limits the light beam in the fluorescent body, thereby solving the problem of uncontrolled emission spot. The circumferentially arranged heat conduction rod in the fluorescent body and the outer skin layer effectively and directionally transport the waste heat accumulated in the fluorescent body under high-power laser excitation, thereby solving the problem of thermal runaway of the fluorescent body. The composite structure fluorescent ceramic can be applied to the fields of laser illumination and display after being packaged with high-power blue laser.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of fluorescent ceramic preparation and laser lighting display, and particularly relates to a composite structure fluorescent ceramic for regulating and controlling photothermal performance and a preparation method and application thereof. BACKGROUND

[0002] Fluorescent ceramic is a kind of ceramic material with special optical and thermal properties, which is widely used in the field of laser lighting technology. Its unique feature is that it has excellent optical transparency and heat resistance, making it a potential choice for high-power lasers and laser modules. Although fluorescent ceramic has many advantages in the field of laser lighting, as researchers explore fluorescent ceramics with better light color performance, fluorescent ceramics have exposed the following problems: ①Light spot out of control problem, which means that the ceramic emission light spot area is much larger than the size of the incident laser, and irregular or distorted phenomena may occur. The size of the light spot may also change over time, temperature or other factors, resulting in unstable light spot size. ②Poor heat dissipation, current fluorescent ceramic lighting devices are mostly homogeneous ceramic structures, which cannot effectively conduct and dissipate heat under high-power laser excitation, resulting in heat shock problems caused by heat accumulation. ③It is difficult to form complex structures. The current ceramic forming based on 3D printing technology generally has the problem of slow forming speed from slurry to green body, resulting in large device error.

[0003] At present, in the literature (Laser Photonics Rev, 2019, 13 (10) 1900147-1-10), the research team found that by introducing air holes as strong scattering sources, the scattering coefficient of the material can be significantly improved, thereby effectively limiting the size of the fluorescent ceramic light spot. However, the research team did not provide an effective means to regulate the size of the fluorescent ceramic light spot. At the same time, in the design of the microstructure of the fluorescent material, the introduction of air holes can effectively improve the scattering coefficient, but it will greatly reduce the thermal conductivity of the material. In the literature (Opt. Express, 2020, 28 (4): 5758-5767), the research team built a professional light spot size test system. Through this test system platform, the research team compared the light spot size limiting ability of a variety of fluorescent materials such as YAG: Ce transparent ceramic, YAG: Ce / Al2O3 composite ceramic, single crystal and various commercial materials. Through comparison experiments, it was found that the difference between the "light spot size" and the "laser spot size" of a single fluorescent material is basically constant.

[0004] Chinese invention patent CN115108822A prepares a light-heat regulated ceramic nanofiber reinforced ZnAl2O4:Eu by embedding γ-AlOOH nanofibers and rare earth Eu3+ into a ZnAl2O4 matrix through thermodynamic strengthening technology 3+ Aerogel. The ceramic fluorescent aerogel prepared by this method has high mechanical strength and high luminescent efficiency, but its heat dissipation performance is still poor, which is not suitable for high-power laser lighting application scenarios.

[0005] Chinese invention patent CN112390641B is based on 3D gel printing technology. First, a gel printing slurry is prepared, and a fiber blank is made using a 3D printer, and then a YAG transparent ceramic optical fiber is prepared after drying, sintering, polishing and a series of treatments. However, the refractive index adjustment range of this transparent ceramic optical fiber is greatly limited.

[0006] Chinese invention patent CN116768628A uses gel casting technology to construct an array core composite structure fluorescent ceramic. The gel state package structure is used as a carrier to construct the core structure to obtain an array core composite structure fluorescent ceramic. This structure realizes light spot regulation through the refractive index difference between the two fluorescent ceramics, but this composite structure fluorescent ceramic lacks heat dissipation design and relies on a single mold, which cannot be personalized designed for different lighting scenarios.

[0007] In the literature (Luminescence Journal, 2024, 52(3)), the research team carried out research on YAG transparent ceramic light-cured 3D printing forming technology, including the development of YAG ceramic slurry, the construction of ceramic green body, and the research on debinding and sintering process of the green body. The research team used vacuum high-temperature sintering process to prepare YAG transparent ceramic with a visible light transmittance of 82.9%. However, the fluorescent ceramic prepared by this method based on light-cured 3D printing technology is a homogeneous single structure, which has poor heat dissipation capacity and light spot control problem in LD / LED lighting scenarios, so it is not suitable for high-power laser lighting scenarios.

[0008] Chinese invention patent CN115925409A uses gel casting process to first make slurry injection molding, and then prepares the core structure of the optical fiber after a series of treatments such as drying and sintering. Then the core is placed in a capillary glass tube, and then the phosphor slurry is injected into it to prepare a core structure optical fiber ceramic. This method realizes high color rendering and high color rendering of ceramic by using two different types of ceramic core and phosphor, but this composite structure ceramic lacks heat dissipation structure design.

[0009] Chinese invention patent CN111825453A utilizes a paste extrusion process and a solid-state sintering process to extrude slurry through infusion devices A and B to produce ceramic optical fibers. The slurries in the two infusion devices are core ceramic slurry and phosphor ceramic slurry, respectively. However, the collimation of the ceramic optical fibers produced by this method is not high, therefore the device quality cannot be guaranteed.

[0010] Therefore, it is of great significance to design fluorescent ceramics with controllable spot size, better heat dissipation, and the ability to be customized to adapt to diverse working scenarios. Summary of the Invention

[0011] To address the aforementioned problems, this invention proposes a composite fluorescent ceramic with modulated photothermal properties, its preparation method, and its application. This composite fluorescent ceramic is a special composite structure ceramic with numerous cylindrical pores, each filled with thermally conductive rods arranged in a circumferential array within the fluorescent ceramic phosphor. Simultaneously, an outer skin layer is added to the outside of the fluorescent ceramic phosphor. Utilizing the total internal reflection effect generated by the refractive index difference between the outer skin layer and the fluorescent ceramic phosphor, the light field can be confined within the phosphor, thereby enhancing the focusing effect.

[0012] One objective of this invention is to provide a composite fluorescent ceramic with modulated photothermal properties. The composite fluorescent ceramic has heat-conducting rods of AlN-Al2O3 arranged in a circumferential array inside. These heat-conducting rods will improve the directional transport capacity of accumulated waste heat inside the phosphor, thereby alleviating the problem of thermal runaway of fluorescent ceramics in high-power lighting scenarios.

[0013] The second objective of this invention is to provide a composite fluorescent ceramic with adjustable photothermal properties. The outer surface of the composite ceramic is coated with an outer skin structure composed of Al2O3 or MgO. The outer skin and the internal fluorescent ceramic phosphor have a refractive index difference, thereby achieving total internal reflection of the light path inside the device. This confines the transmitted light field to the inside of the phosphor, thereby improving the problem of uncontrolled light spot in laser lighting devices.

[0014] The third objective of this invention is to provide a method for the rapid prototyping of composite fluorescent ceramics with regulated photothermal properties. By using UV curing technology to rapidly solidify the ceramic slurry, the method solves the problem of slow molding speed in the process of forming fluorescent ceramic devices from fluid slurry to solid.

[0015] The fourth objective of this invention is to provide a composite fluorescent ceramic that, through the stacking and combination of composite fluorescent ceramic units, can be applied to lighting applications with different size requirements.

[0016] To achieve the above objectives, the technical solution adopted in this invention is as follows: After preparing ceramic slurry for the phosphor, heat-conducting rods, and outer skin in the composite structure, the various structures are extruded and printed using 3D printing technology. During the 3D printing process, UV light (405nm wavelength ultraviolet light) is used for irradiation, thereby achieving rapid curing and molding of the extruded material. The heat-conducting rod structure is arranged in a periodic circumferential array within the phosphor structure, and the cross-section of each heat-conducting rod structure is circular. The area ratio of the heat-conducting rod structure is 16.67% to 25%, and the phosphor structure is composed of Ca3Sc2Si3O. 12 :Ce 3+ YAG:Ce and CaAlSiN3:Eu 2 + The mixture has a heat-conducting rod structure of AlN-Al2O3 mixture and an outer skin structure of Al2O3 or MgO.

[0017] The photopolymerization 3D printing mechanism of this invention includes a three-axis slide rail (x-axis, y-axis, z-axis), a computer, an air compressor, a pneumatic two-piece assembly, a slurry nozzle, a slurry delivery pipe, a storage tank, a UV lamp cover, and a substrate. The slurry nozzle moves spatially via the x-axis, y-axis, and z-axis slide rails. The air compressor is connected to the pneumatic two-piece assembly via an air duct. The computer is connected to the 3D printing mechanism and the UV lamp cover via wires, controlling the slurry extrusion and the spatial movement of the nozzle mechanism, respectively. The storage tank is connected to the nozzle via the slurry delivery pipe, and the UV lamp cover is connected to the substrate.

[0018] Furthermore, the slurry in the storage box is delivered by air pressure through slurry delivery pipes to the same slurry nozzle. The slurry nozzle has three slurry extrusion ports, each with a diameter of 0.2 mm. Under computer control, the extrusion ports work alternately.

[0019] Furthermore, the air compressor is connected to the pneumatic double-unit via an air duct, and the pneumatic double-unit is sealed to the liquid storage tank. Gas pressure forces the slurry out of the extrusion nozzle. The computer is connected to the 3D printer via wires to control the spatial movement of the nozzle and the alternating extrusion of the slurry.

[0020] Furthermore, the slurry storage tank is equipped with an integrated resistive humidity sensor to monitor the slurry's humidity level in real time. Simultaneously, the storage tank utilizes an ultrasonic atomizer to provide humidification, releasing an appropriate amount of atomized moisture according to the control system's instructions. This prevents the ceramic slurry from drying out excessively and clumping due to changes in time and temperature during printing.

[0021] A composite fluorescent ceramic with modulated photothermal properties is composed of several luminescent units stacked together. Each luminescent unit consists of an outer skin layer (which also functions as a light-modulating and heat-conducting layer), a phosphor (emitting light), and a heat-conducting rod. The outer skin layer circumferentially covers the surface of the phosphor, and the heat-conducting rods are arranged in a circumferential array inside the phosphor. The outer skin layer is composed of component E, the phosphor is composed of component F, and the heat-conducting rods are composed of component G, wherein E is at least one of Al₂O₃ and MgO; F is composed of... a Ca3Sc2Si3O 12 :Ce 3+ - b YAG:Ce- c CaAlSiN3:Eu 2+ The mixture, 0.1≤ a≤ 0.2, 0.075 ≤c≤ 0.15, b =1- a - c G is x Al2O3- y A mixture of AlN, 0.25≤ x ≤0.75, y =1- x .

[0022] Furthermore, the refractive index of the outer skin layer is less than that of the phosphor and it has a high thermal conductivity of 25~30 W / (m·K), while the heat-conducting rod has a high thermal conductivity of 30~33 W / (m·K).

[0023] The method for preparing composite fluorescent ceramics with regulated photothermal properties using photopolymerization 3D printing, as described in this invention, utilizes photopolymerization 3D printing technology to directly write and print devices. After preparing the outer skin layer, phosphor, and heat-conducting rod slurry, they are placed in their respective slurry containers. Three coordinate systems are set up using the X-axis distances of three extrusion nozzles. The three extrusion nozzles are alternately used to print the various structures of the composite ceramic layer by layer. Specifically, the outer skin layer structure is printed first, followed by the phosphor structure, and finally the heat-conducting rod structure, ultimately obtaining a composite ceramic with regulated photothermal properties. The method includes the following steps:

[0024] (1) Preparation of outer skin layer slurry:

[0025] ① Powder modification: Wetting and dispersing agent BYK w969 (BYK GmbH, Germany), surfactant amine oxide OA, and 3-(isobutenoyloxy)propyltrimethoxysilane Silane A174 were sequentially added to a 95wt% ethanol solution prepared with ultrapure water and anhydrous ethanol, and ultrasonically dispersed for 10 min; a powder with a density of 3.5~3.58 g / cm³ was slowly added. 3 The α-phase Al₂O₃ raw material powder has a density of 3.5~3.58 g / cm³. 3The MgO raw material powder was magnetically stirred at 70℃ for 1 hour; the resulting suspension was filtered, washed three times, and the obtained powder was vacuum dried at 60℃ for 36 hours; then the dried powder was transferred to a mortar, ground and crushed, and passed through a 100-mesh sieve to obtain modified Al2O3 powder or modified MgO powder; wherein the amounts of BYK w969, OA, and Silane A174 were 5 wt% of the α-phase Al2O3 raw material powder or MgO raw material powder, respectively.

[0026] ② Slurry preparation: The wet dispersant BYK w969 (BYK GmbH, Germany), surfactant amine oxide OA, polyethylene glycol 200 (the crosslinking agent used in photocuring), sodium oleate, and dispersant KOS 110 were added to the photocurable material, followed by ultrasonic dispersion for 30 minutes. Then, the modified Al2O3 powder or modified MgO powder prepared in step ① was slowly added, and the mixture was mechanically stirred for 2 hours to obtain a premix. The premix was ball-milled at 300 r / min for 10 hours, and then vacuum-defoamed at 60°C for 1 hour to obtain a uniform, bubble-free photocurable Al2O3 slurry or MgO slurry, which is the outer skin layer slurry. The photocurable material was prepared by mixing PPTTA, TMPTA, and HDDA in a weight ratio of 1:4:5, and the weight ratio of the photocurable material to the modified Al2O3 powder or modified MgO powder was 10:1. Ethylene oxide (5) pentaerythritol tetraacrylate acts as a UV monomer in the photocuring technology; TMPTA is trimethylolpropane triacrylate, which acts as a crosslinking agent in the photocuring technology; HDDA is 1,6-hexanediol diacrylate, which acts as a UV monomer in the photocuring technology; the addition amounts of YK w969, OA, polyethylene glycol 200, sodium oleate and KOS 110 are all 5wt% of modified Al2O3 powder or modified MgO powder.

[0027] (2) Preparation of phosphor paste:

[0028] ① Mix the phosphor with ceramic raw material powder ( a Ca3Sc2Si3O 12 :Ce 3+ - b YAG:Ce- c CaAlSiN3:Eu 2+ , 0.1≤ a≤ 0.2, 0.075 ≤c≤ 0.15, b =1- a - cA mixed powder was prepared by stirring and mixing the UV monomer with Sudan Red 3 (a light absorber), TPO (a photoinitiator), and UV monomer, followed by drying. The particle size of the mixed powder was 250 nm-300 nm. The weight ratio of UV monomer to mixed ceramic raw material powder was 10:1. The UV monomer was a mixture of hexanediol diacrylate and pentaerythritol tetraacrylate ethoxylate in a mass ratio of 4:1. The amounts of Sudan Red 3 (a light absorber) and TPO (a photoinitiator) were both 0.4 wt% to 1.5 wt% of the UV monomer.

[0029] ② Add the dispersant ammonium citrate and the pH adjuster tetramethylammonium hydroxide to deionized water to prepare a phosphor structure premix; wherein, based on the mass of the mixed powder in step ①, the amount of ammonium citrate is 0.35 wt% and the amount of tetramethylammonium hydroxide is 1.2 wt%.

[0030] ③ The raw material powder after drying in step ① is added to the phosphor structure premix in step ② in four to five batches. The first batch contains 50% of the total mass of the raw material powder. After all the raw material powder is added to the premix, it is ball-milled at low speed. Then, monomer acrylamide AM and N,N'-methylenebisacrylamide are added and ball-milled at low speed. After ball milling, the slurry is degassed to obtain a phosphor slurry stock solution with a solid content of 40 vol% to 48 vol%. The ball milling speed is 50-90 r / min, the grinding balls are high-purity alumina balls, and the mass ratio of raw material powder to high-purity alumina balls is 0.8:1.9. Based on the mass of the raw material mixed powder, the amount of monomer acrylamide AM added is 2.0 wt%, and the mass ratio of monomer acrylamide AM to N,N'-methylenebisacrylamide is 1:10 to 1:12.

[0031] ④ Add the catalyst tetramethylethylenediamine solution to the phosphor slurry stock solution obtained in step ③, stir, then add the initiator ammonium persulfate solution and stir evenly to obtain the phosphor slurry; the solid content of the prepared phosphor slurry is 40 vol%~48 vol%; wherein the concentration of tetramethylethylenediamine solution is 25 wt%, the concentration of ammonium persulfate solution is 8 wt%, the amount of tetramethylethylenediamine solution added is 0.05-0.3 vol% of the phosphor slurry stock solution; the amount of ammonium persulfate solution added is 0.4-0.6 vol% of the phosphor slurry stock solution.

[0032] (3) Preparation of heat-conducting rod slurry:

[0033] ① Mix 200g of aluminum nitride and aluminum oxide powder x Al2O3- y AlN (0.25≤ x≤0.75, y=1-x) was dispersed in 100 mL of anhydrous ethanol, and Sudan Red 3 (light absorber), TPO (photoinitiator), and UV monomer were added and stirred to obtain a suspension; wherein, the UV monomer and aluminum nitride and alumina mixed powder were mixed. x Al2O3- y The weight ratio of AlN is 10:1, and the UV monomer is a mixture of hexanediol diacrylate and pentaerythritol tetraacrylate in a mass ratio of 4:1. Based on the mass of the mixed powder, 1-7 wt% of polymaleic anhydride HPMA is added to the above suspension. Then, it is added to a ball mill jar, wherein the mass ratio of zirconia balls to aluminum nitride to aluminum oxide mixed powder in the ball mill jar is 2:1. The mixture is ball-milled at 250 r / min for 12 h to obtain a completely dispersed and uniform mixed suspension. The mixed suspension is then centrifuged, filtered, washed, and dried in an oven at 55℃ for 12 h to obtain a surface-modified aluminum oxide and aluminum nitride mixed powder.

[0034] ② The surface-modified alumina and aluminum nitride mixed powder is dispersed in deionized water to obtain a modified powder suspension. Then, polyvinyl alcohol (PVA) is added as a binder. The amount of PVA is 1-3 wt% based on the weight of the modified powder suspension. The pH is adjusted to 7.0 with NH3·H2O. Based on the mass of the surface-modified alumina and aluminum nitride mixed powder, 1-7 wt% of polymaleic anhydride (HPMA) is added to the above suspension. Then, the mixture is added to a ball mill jar, wherein the ball mill jar contains zirconia balls. The mass ratio of aluminum nitride to aluminum oxide mixed powder is 2:1. The mixture is continuously ball-milled at 250 r / min for 2 h. After adding plasticizer phthalate and defoamer, the mixture is continuously ball-milled at 250 r / min for 2 h to finally obtain a heat-conducting rod slurry with a solid content of 70-75%. The defoamer used is Daida Chemical (GN-56). Based on the weight of the modified powder suspension, the amount of plasticizer phthalate is 1 wt%, and the amount of defoamer is 0.2-1 wt%.

[0035] (4) Using photopolymer 3D printing technology, the three types of pastes were directly written to print various structures:

[0036] ① Place the phosphor paste, the heat-conducting rod paste, and the outer skin paste into their respective paste storage boxes;

[0037] ② Set nozzles 1, 2, and 3 as three coordinate systems. The coordinate system of nozzle 1 is translated along the x-axis by the distance between the nozzle centers to obtain the coordinate system of nozzle 2. The coordinate system of nozzle 2 is then translated along the x-axis by the distance between the nozzle centers to obtain the coordinate system of nozzle 3. The fluorescent ceramic structure model is sliced. The printing speed is set to 3 mm / s, the printing pressure range to 65-75 psi, the printing platform temperature to 30℃, and the slice thickness to 0.1 mm (slightly smaller than the nozzle diameter to ensure complete overlap between adjacent layers). Using photopolymer 3D printing technology, nozzle 1 first prints an outer skin structure. After curing, nozzle 3 prints a heat-conducting rod structure, and after curing, nozzle 2 prints the phosphor structure of the fluorescent ceramic. The three nozzles are used alternately, printing layer by layer, with UV curing applied layer by layer throughout the process, finally obtaining a composite ceramic preform.

[0038] (5) Remove the glue from the 3D printed blank and perform post-processing. Remove the support structure, clean and dry the printed part, and clean and trim the surface at the same time. Then transfer it to a temperature and humidity control box, where the temperature is controlled at 30~40℃ and the humidity is controlled at 75~80%, and let it stand for 10~15 hours.

[0039] (6) Place the dried green body in a crucible for bisque firing, and then bisque fire in a muffle furnace to remove the organic matter in the green body. Hold at 380℃~390℃ for 10h to 12h. Hold at 700℃~800℃ for 6h to 8h.

[0040] (7) The calcined green blank is sintered in an argon atmosphere at 1490℃~1510℃ for 10h~15h, and then cooled to room temperature to obtain a composite fluorescent ceramic with controlled photothermal properties.

[0041] The present invention also provides the application of the composite structure fluorescent ceramic with controlled photothermal properties in the field of fluorescence conversion LD laser lighting, wherein the outer skin layer is wrapped around the phosphor and its cross-sectional area is 1% to 3% of the cross-sectional area of ​​the entire device, the number of heat-conducting rods is controlled at 35 to 44, and the total cross-sectional area of ​​the heat-conducting rods is controlled at 16.67% to 25% of the cross-sectional area of ​​the device.

[0042] Furthermore, when the composite fluorescent ceramic with controlled photothermal properties is applied to LD laser lighting devices, the excitation source is a blue LD laser.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The composite structure fluorescent ceramic preparation method proposed in this invention combines 3D printing technology. Compared with existing traditional ceramic forming methods such as manual molding or pressing, this preparation method has no limitations on processes and molds, and can realize complex shapes and structures of devices.

[0045] 2. The composite fluorescent ceramic preparation method proposed in this invention uses UV curing technology, which improves upon the slow molding speed of existing 3D printed ceramic technology after the slurry is extruded from the nozzle. Its curing process is layer-by-layer, and the curing time is short. Compared with existing technologies, the preparation method proposed in this invention can significantly shorten the manufacturing cycle and improve production efficiency.

[0046] 3. This invention designs a circumferential array structure of heat-conducting rods inside the phosphor ceramic to improve the problem of heat runaway and enhance the heat dissipation capacity of the device by directional heat transport.

[0047] 4. The present invention designs an outer skin structure on the outer surface of the fluorescent host, which can achieve total internal reflection by taking advantage of the high refractive index difference between the two materials, the coating layer and the outer skin layer. This allows the light field to be confined within the core of the device, thereby improving the light focusing ability of the device and improving the problem of light spot runaway.

[0048] 5. By changing the 3D printing parameters, this invention can change the diameter and number of heat dissipation rods of the device, thereby achieving a balance between the device's light-emitting performance and heat dissipation level. At the same time, the light-concentrating layer can be customized through the personalized design of the 3D printing parameters to adjust the light spot expansion ratio, so as to adapt to different laser lighting application scenarios.

[0049] 6. This invention provides a method for preparing composite fluorescent ceramics using photopolymerization 3D printing. The fluorescent ceramics prepared by this method have controllable thickness, are simple to process, and are suitable for large-scale production.

[0050] 7. The composite ceramic unit designed in this invention can be stacked and combined to design different honeycomb structures, thereby enabling personalized design for lighting application scenarios of different sizes.

[0051] 8. In the method for preparing composite fluorescent ceramics with regulated photothermal properties proposed in this invention, the 3D printing mechanism is designed with three material storage boxes connected to the same nozzle, and printing is performed alternately through three sets of coordinate systems set up through three extrusion ports. In existing 3D printing methods, it is necessary to replace one type of slurry after it is used up, and the cleaning of the material boxes reduces production efficiency. Therefore, the improved method proposed in this invention improves production efficiency while avoiding cross-contamination between the two types of slurries.

[0052] 9. The total internal reflection effect generated by the refractive index difference between the outer skin and the phosphor in this invention confines the light beam inside the phosphor, thereby solving the problem of uncontrolled emission spot. The heat-conducting rods arranged in a circumferential array inside the phosphor and the outer skin effectively and directionally transport the waste heat accumulated inside the phosphor under high-power laser excitation, thus solving the problem of thermal runaway in the phosphor. This composite fluorescent ceramic structure can withstand high-power-density blue laser excitation and emits high-quality white light with high beam collimation, high brightness, and high luminous flux. After encapsulation with a high-power blue laser, this composite fluorescent ceramic structure can be applied to the fields of laser lighting and display. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of a single light-emitting unit in a composite fluorescent ceramic structure for regulating photothermal performance, as proposed in this invention.

[0054] Figure 2 This is a schematic diagram of the composite fluorescent ceramic structure for regulating photothermal properties proposed in this invention.

[0055] Figure 3 This is a schematic diagram of heat transport in the heat-conducting rod structure proposed in this invention.

[0056] Figure 4 This is a schematic diagram of the phosphor structure light spot modulation proposed in this invention.

[0057] Figure 5 This is a schematic diagram of the photopolymerization 3D printing molding device proposed in this invention.

[0058] Figure 6 This is a schematic diagram of the nozzle head in the photopolymerization 3D printing molding device proposed in this invention. Detailed Implementation

[0059] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above-described invention.

[0060] The preparation method of the outer skin layer slurry in this invention is as follows:

[0061] ① Powder modification: Wetting and dispersing agent BYK w969 (BYK GmbH, Germany), surfactant ammonium oxide OA, and 3-(isobutyryloxy)propyltrimethoxysilane Silane A174 were sequentially added to a 95wt% ethanol solution prepared with ultrapure water and anhydrous ethanol, and ultrasonically dispersed for 10 min; a powder with a density of 3.5~3.58 g / cm³ was slowly added. 3 The α-phase Al₂O₃ raw material powder has a density of 3.5~3.58 g / cm³. 3The MgO raw material powder was magnetically stirred at 70℃ for 1 hour; the resulting suspension was filtered, washed three times, and the obtained powder was vacuum dried at 60℃ for 36 hours; then the dried powder was transferred to a mortar, ground and crushed, and passed through a 100-mesh sieve to obtain modified Al2O3 powder or modified MgO powder; wherein the amounts of BYK w969, OA, and Silane A174 were 5 wt% of the α-phase Al2O3 raw material powder or MgO raw material powder, respectively.

[0062] ② Slurry preparation: The wet dispersant BYK w969 (BYK GmbH, Germany), surfactant ammonium oxide OA, polyethylene glycol 200 (crosslinking agent used in photocuring), sodium oleate, and dispersant KOS 110 were added to the photocurable material, followed by ultrasonic dispersion for 30 minutes. Then, the modified Al2O3 powder or modified MgO powder prepared in step ① was slowly added, and the mixture was mechanically stirred for 2 hours to obtain a premix. The premix was ball-milled at 300 r / min for 10 hours, and then vacuum-defoamed at 60°C for 1 hour to obtain a uniform, bubble-free photocurable Al2O3 slurry or MgO slurry, which is the outer skin layer slurry. The photocurable material was prepared by mixing PPTTA, TMPTA, and HDDA in a weight ratio of 1:4:5, and the weight ratio of the photocurable material to the modified Al2O3 powder or modified MgO powder was 10:1. Ethylene oxide (5) pentaerythritol tetraacrylate acts as a UV monomer in the photocuring technology; TMPTA is trimethylolpropane triacrylate, which acts as a crosslinking agent in the photocuring technology; HDDA is 1,6-hexanediol diacrylate, which acts as a UV monomer in the photocuring technology; the addition amounts of YK w969, OA, polyethylene glycol 200, sodium oleate and KOS 110 are all 5wt% of modified Al2O3 powder or modified MgO powder.

[0063] The preparation method of the phosphor paste in this invention is as follows:

[0064] ① Mix the phosphor with ceramic raw material powder ( a Ca3Sc2Si3O 12 :Ce 3+ - b YAG:Ce- c CaAlSiN3:Eu 2+ , 0.1≤ a≤ 0.2, 0.075 ≤c≤ 0.15, b =1- a - cA mixed powder was prepared by stirring and mixing the UV monomer with Sudan Red 3 (a light absorber), TPO (a photoinitiator), and UV monomer, followed by drying. The particle size of the mixed powder was 250 nm-300 nm. The weight ratio of UV monomer to mixed ceramic raw material powder was 10:1. The UV monomer was a mixture of hexanediol diacrylate and pentaerythritol tetraacrylate ethoxylate in a mass ratio of 4:1. The amounts of Sudan Red 3 (a light absorber) and TPO (a photoinitiator) were both 0.4 wt% to 1.5 wt% of the UV monomer.

[0065] ② Add the dispersant ammonium citrate and the pH adjuster tetramethylammonium hydroxide to deionized water to prepare a phosphor structure premix; wherein, based on the mass of the mixed powder in step ①, the amount of ammonium citrate is 0.35 wt% and the amount of tetramethylammonium hydroxide is 1.2 wt%.

[0066] ③ The raw material powder after drying in step ① is added to the phosphor structure premix in step ② in four to five batches. The first batch contains 50% of the total mass of the raw material powder. After all the raw material powder is added to the premix, it is ball-milled at low speed. Then, monomer acrylamide AM and N,N'-methylenebisacrylamide are added and ball-milled at low speed. After ball milling, the slurry is degassed to obtain a phosphor slurry stock solution with a solid content of 40 vol% to 48 vol%. The ball milling speed is 50-90 r / min, the grinding balls are high-purity alumina balls, and the mass ratio of raw material powder to high-purity alumina balls is 0.8:1.9. Based on the mass of the raw material mixed powder, the amount of monomer acrylamide AM added is 2.0 wt%, and the mass ratio of monomer acrylamide AM to N,N'-methylenebisacrylamide is 1:10 to 1:12.

[0067] ④ Add the catalyst tetramethylethylenediamine solution to the phosphor slurry stock solution obtained in step ③, stir, then add the initiator ammonium persulfate solution and stir evenly to obtain the phosphor slurry; the solid content of the prepared phosphor slurry is 40 vol%~48 vol%; wherein the concentration of tetramethylethylenediamine solution is 25 wt%, the concentration of ammonium persulfate solution is 8 wt%, the amount of tetramethylethylenediamine solution added is 0.05-0.3 vol% of the phosphor slurry stock solution; the amount of ammonium persulfate solution added is 0.4-0.6 vol% of the phosphor slurry stock solution.

[0068] The preparation method of the heat-conducting rod slurry in this invention is as follows:

[0069] ① Mix 200g of aluminum nitride and aluminum oxide powder x Al2O3- y AlN (0.25≤ x≤0.75, y=1-x) was dispersed in 100 mL of anhydrous ethanol, and Sudan Red 3 (light absorber), TPO (photoinitiator), and UV monomer were added and stirred to obtain a suspension; wherein, the UV monomer and aluminum nitride and alumina mixed powder were mixed. x Al2O3- y The weight ratio of AlN is 10:1, and the UV monomer is a mixture of hexanediol diacrylate and pentaerythritol tetraacrylate in a mass ratio of 4:1. Based on the mass of the mixed powder, 1-7 wt% of polymaleic anhydride HPMA is added to the above suspension. Then, it is added to a ball mill jar, wherein the mass ratio of zirconia balls to aluminum nitride to aluminum oxide mixed powder in the ball mill jar is 2:1. The mixture is ball-milled at 250 r / min for 12 h to obtain a completely dispersed and uniform mixed suspension. The mixed suspension is then centrifuged, filtered, washed, and dried in an oven at 55℃ for 12 h to obtain a surface-modified aluminum oxide and aluminum nitride mixed powder.

[0070] ② The surface-modified alumina and aluminum nitride mixed powder is dispersed in deionized water to obtain a modified powder suspension. Then, polyvinyl alcohol (PVA) is added as a binder. The amount of PVA is 1-3 wt% based on the weight of the modified powder suspension. The pH is adjusted to 7.0 with NH3·H2O. Based on the mass of the surface-modified alumina and aluminum nitride mixed powder, 1-7 wt% of polymaleic anhydride (HPMA) is added to the above suspension. Then, the mixture is added to a ball mill jar, wherein the ball mill jar contains zirconia balls. The mass ratio of aluminum nitride to aluminum oxide mixed powder is 2:1. The mixture is continuously ball-milled at 250 r / min for 2 h. After adding plasticizer phthalate and defoamer, the mixture is continuously ball-milled at 250 r / min for 2 h to finally obtain a heat-conducting rod slurry with a solid content of 70-75%. The defoamer used is Daida Chemical (GN-56). Based on the weight of the modified powder suspension, the amount of plasticizer phthalate is 1 wt%, and the amount of defoamer is 0.2-1 wt%.

[0071] Example 1

[0072] The preparation method of the composite fluorescent ceramic with controlled photothermal properties in this embodiment is as follows:

[0073] In this embodiment, a schematic diagram of the composite fluorescent ceramic structure for regulating photothermal properties is shown below. Figure 2 As shown, the dotted circular structure in the cross-section is a heat-conducting rod structure, the yellow-red filling part is a fluorescent ceramic phosphor structure, and the outer ring is an outer skin layer structure. The raw materials used in the following examples are all commercially available products, and the particle size range of the raw material powders for the phosphor, heat-conducting rod, and outer skin layer is 300 nm.

[0074] The photopolymerization 3D printing mechanism proposed in this invention includes a three-axis slide rail (x-axis, y-axis, z-axis), a computer, an air compressor, a pneumatic two-piece assembly, a slurry nozzle, a slurry delivery pipe, a storage tank, a UV lamp cover, and a substrate. The slurry nozzle moves spatially via the x-axis, y-axis, and z-axis slide rails. The air compressor is connected to the pneumatic two-piece assembly via an air duct. The computer is connected to the 3D printing mechanism via wires and the pneumatic two-piece assembly, controlling the slurry extrusion and the spatial movement of the nozzle mechanism, respectively. The storage tank is connected to the nozzle via the slurry delivery pipe, and the UV lamp cover is connected to the substrate.

[0075] The slurry in the storage tank is delivered by air pressure through slurry delivery pipes to the same slurry nozzle. The slurry nozzle has three slurry extrusion ports, all with the same diameter. The three extrusion ports operate alternately under computer control.

[0076] An air compressor is connected to a pneumatic two-piece unit via an air duct, and the pneumatic two-piece unit is sealed to a liquid storage tank. Gas pressure forces the slurry out of the extrusion nozzle. Simultaneously, a computer is connected to the 3D printer via wires to control the spatial movement of the nozzle and the alternating extrusion of the slurry. The preparation process is as follows:

[0077] (1) Preparation of heat-conducting rod slurry (solid content 70%)

[0078] (2) Preparation of phosphor paste (solid content 40 vol%):

[0079] (3) After preparing the outer skin layer slurry (the preparation method is the same as in Example 1),

[0080] (4) Place the three slurries obtained into their respective storage boxes. Then set nozzles 1, 2 and 3 as three coordinate systems, slice the model, and set the printing speed to 3 mm / s, platform temperature to 30℃ and slice thickness to 0.1 mm. Start printing. During the printing process, use a UV lamp (405nm wavelength light) for photocuring. Nozzle 1 first prints a phosphor structure 2. After curing, nozzle 2 prints a heat-conducting rod structure 3. After curing, print the outer skin structure 1 (e.g. Figure 1 (As shown). The three extrusion nozzles are alternately used, printing and curing layer by layer to obtain the preform. The design includes 37 heat-conducting rods, with the cross-sectional area of ​​the heat-conducting rods accounting for 17% of the total cross-sectional area of ​​the device, and the cross-sectional area of ​​the outer skin layer accounting for 1% of the total cross-sectional area of ​​the device.

[0081] (5) Remove the glue from the 3D printed blank and perform post-processing. Remove the support structure, clean and dry the printed part, and clean and trim the surface at the same time. Then transfer it to a temperature and humidity control box, where the temperature is controlled at 40°C and the humidity is controlled at 75%, and let it stand for 15 hours.

[0082] (6) Place the dried blank in a crucible for bisque firing, and then bisque fire in a muffle furnace to remove the organic matter in the blank. Hold at 390°C for 12 hours and at 800°C for 7 hours.

[0083] (7) The calcined green blank was sintered in an argon atmosphere at 1500℃ for 15h, and then cooled to room temperature to obtain a composite fluorescent ceramic with controlled photothermal properties.

[0084] The composite fluorescent ceramic obtained in Example 1 was excited by a 455 nm blue laser, and the light source spot expansion ratio was 1.28. The device was 92.6 °C after being excited for 1 minute.

[0085] Example 2

[0086] The preparation method of the composite fluorescent ceramic with controlled photothermal properties in this embodiment is as follows:

[0087] (1) After preparing the slurry for the heat-conducting rod structure (73% solid content), the phosphor structure slurry (45 vol% solid content), and the ceramic slurry for the outer skin layer (preparation method is the same as in Example 1), the obtained slurries were placed in their respective storage boxes. Then, nozzles 1, 2, and 3 were set as three coordinate systems, and the model was sliced. The printing speed was set to 3 mm / s, the platform temperature to 30℃, and the slice thickness to 0.1 mm. Printing was started, and UV lamps (405 nm wavelength light) were used for photocuring during the printing process. Nozzle 1 first printed a layer of phosphor structure, and after curing, nozzle 2 printed the heat-conducting rod structure, and after curing, the outer skin layer structure was printed. The three extrusions were used alternately, printing and curing layer by layer to obtain the blank. The heat-conducting rod structure was designed to have 40 rods, the cross-sectional area of ​​which was 20% of the total cross-sectional area of ​​the device, and the cross-sectional area of ​​the outer skin layer was 2% of the total cross-sectional area of ​​the device.

[0088] (2) Remove the glue from the 3D printed blank and perform post-processing. Remove the support structure, clean and dry the printed part, and clean and trim the surface at the same time. Then transfer it to a temperature and humidity control box, where the temperature is controlled at 30°C and the humidity is controlled at 78%, and let it stand for 5 hours.

[0089] (3) Place the dried blank in a crucible for bisque firing, and then bisque fire in a muffle furnace to remove the organic matter in the blank. Keep it at 390℃ for 12 hours and at 800℃ for 7 hours.

[0090] (4) The calcined green blank was sintered in an argon atmosphere at 1500℃ for 15h, and then cooled to room temperature to obtain a composite fluorescent ceramic with controlled photothermal properties.

[0091] The composite fluorescent ceramic obtained in Example 2 was excited by a 455 nm blue laser, and the light source spot expansion ratio was 1.26. The device was 83.3 °C after being excited for 1 minute.

[0092] Example 3

[0093] The preparation method of the composite fluorescent ceramic with controlled photothermal properties in this embodiment is as follows:

[0094] (1) After preparing the slurry for the heat-conducting rod structure (75% solid content), the phosphor structure slurry (48 vol% solid content), and the ceramic slurry for the outer skin layer (preparation method is the same as in Example 1), the obtained slurries were placed in their respective storage boxes. Then, nozzles 1, 2, and 3 were set as three coordinate systems, and the model was sliced. The printing speed was set to 3 mm / s, the platform temperature to 30℃, and the slice thickness to 0.1 mm. Printing was started, and UV lamps (405 nm wavelength light) were used for photocuring during the printing process. Nozzle 1 first printed a layer of phosphor structure, and after curing, nozzle 2 printed the heat-conducting rod structure, and after curing, the outer skin layer structure was printed. The three extrusions were used alternately, printing and curing layer by layer to obtain the blank. The heat-conducting rod structure was designed to have 44 rods, the cross-sectional area of ​​which was 25% of the total cross-sectional area of ​​the device, and the cross-sectional area of ​​the outer skin layer was 3% of the total cross-sectional area of ​​the device.

[0095] (2) Remove the glue from the 3D printed blank and perform post-processing. Remove the support structure, clean and dry the printed part, and clean and trim the surface at the same time. Then transfer it to a temperature and humidity control box, where the temperature is controlled at 30°C and the humidity is controlled at 80%, and let it stand for 5 hours.

[0096] (3) Place the dried blank in a crucible for bisque firing, and then bisque fire in a muffle furnace to remove the organic matter in the blank. Keep it at 390℃ for 12 hours and at 800℃ for 7 hours.

[0097] (4) The calcined green blank was sintered in an argon atmosphere at 1500℃ for 15h, and then cooled to room temperature to obtain a composite fluorescent ceramic with controlled photothermal properties.

[0098] The composite fluorescent ceramic obtained in Example 3 was excited by a 455 nm blue laser, and the resulting spot expansion ratio was 1.19. The device was 72 °C after being excited for 1 minute.

[0099] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A composite structure fluorescent ceramic for regulating photothermal performance, characterized by, The composite structure ceramic is composed of a plurality of light emitting units, each of which is composed of an outer skin layer, a fluorescent body and a heat conducting rod in sequence, wherein the outer skin layer circumferentially covers the surface layer of the fluorescent body, and the heat conducting rods are circumferentially arranged in the fluorescent body. The circumferentially wrapped sheath layer component is E, the phosphor component is F, and the heat conducting rod component is G, wherein E is a mixture of AI2O3, MgO, at least one of a Ca3Sc2Si3O 12 :Ce 3+ - b YAG:Ce- c CaAlSiN3:Eu 2+ 0.1 a≤ 0.2, 0.075 ≤c≤ 0.15, b =1- a - c ; G is a mixture of x AI2O3- y AlN, 0.25 x ≤0.75, y =1- x .

2. The composite structure fluorescent ceramic for regulating photothermal performance according to claim 1, characterized in that: The outer skin layer has a refractive index less than that of the fluorescent body and a high thermal conductivity of 25-30 W / (m·K), and the heat conducting rod has a high thermal conductivity of 30-33 W / (m·K).

3. The method of claim 1, wherein the composite structure fluorescent ceramic having a controlled photothermal property is prepared by the steps of: preparing a precursor solution by dissolving a metal salt and a polymer in a solvent; preparing a precursor film by coating the precursor solution on a substrate; and preparing a composite structure fluorescent ceramic by sintering the precursor film. The device is directly printed by using the light-curing 3D printing technology, the outer skin layer, the fluorescent body and the heat conducting rod slurry are placed in the respective slurry boxes after preparation, three sets of coordinate systems are set by the X-axis distance of the three extrusion outlets, and the structures of the composite structure ceramic are printed layer by layer in turn, i.e., the outer skin layer structure is printed first, then the fluorescent body structure is printed, and finally the heat conducting rod structure is printed, so that the composite structure ceramic with regulated photo-thermal performance is obtained, which specifically comprises the following steps: (1) preparing the outer skin layer slurry; (2) preparing the fluorescent body slurry; (3) preparing the heat conducting rod slurry; (4) directly printing the structures by using the light-curing 3D printing technology; (5) degumming and drying the printed body, placing it in a crucible for preliminary firing, discharging the organic matter in the preliminary fired body in a muffle furnace, and then sintering it in an argon atmosphere to obtain the composite structure fluorescent ceramic with regulated photo-thermal performance.

4. The method of claim 3, wherein the composite structure fluorescent ceramic having a controlled photothermal property is prepared by the steps of: preparing a precursor solution by dissolving a metal salt and a polymer in a solvent; preparing a precursor film by applying the precursor solution to a substrate; and preparing a composite structure fluorescent ceramic by heat-treating the precursor film. The preparation method of the outer skin layer slurry in step (1) is as follows: Powder modification: wetting dispersant BYK w969, surfactant amine oxide OA and 3-(isobutenoyloxy) propyl trimethoxysilane Silane A174 were added into 95wt% ethanol solution prepared by ultrapure water and anhydrous ethanol respectively, and ultrasonic dispersion was carried out for 10min; α phase Al2O3 raw powder with density of 3.5~3.58g / cm 3 or MgO raw powder with density of 3.5~3.58g / cm 3 was slowly added, and magnetic stirring was carried out at 70℃ for 1h; the obtained suspension was suction filtered, washed for 3 times, and the obtained powder was vacuum dried at 60℃ for 36h; then the dried powder was moved into a mortar, ground and crushed, and passed through a 100 mesh screen to obtain modified Al2O3 powder or modified MgO powder; wherein the amount of BYK w969, OA and Silane A174 was 5wt% of the α phase Al2O3 raw powder or MgO raw powder respectively; Slurry preparation: wet dispersant BYK w969, surfactant amine oxide OA, polyethylene glycol 200, sodium oleate and dispersant KOS 110 are added into a light-curing material, then ultrasonic dispersion is performed for 30 min, then modified Al2O3 powder or modified MgO powder prepared in step ① is slowly added, mechanical stirring is performed for 2 h to obtain a premix; the premix is ball milled in a ball mill at a speed of 300 r / min for 10 h, and vacuum degassing is performed at 60℃ for 1 h by using a vacuum drying box to obtain a uniform and bubble-free light-curing Al2O3 slurry or MgO slurry, which is the outer skin layer slurry; the light-curing material is prepared by mixing PPTTA, TMPTA and HDDA in a weight ratio of 1:4:5, and the weight ratio of the light-curing material to the modified Al2O3 powder or the modified MgO powder is 10:1; wherein PPTTA is ethoxylated (5) pentaerythritol tetraacrylate, which acts as a UV monomer in the light-curing technology; TMPTA is trimethylolpropane triacrylate, which acts as a crosslinking agent in the light-curing technology; HDDA is 1,6-hexanediol diacrylate, which acts as a UV monomer in the light-curing technology; the addition amounts of YK w969, OA, polyethylene glycol 200, sodium oleate and KOS 110 are all 5wt% of the modified Al2O3 powder or the modified MgO powder.

5. The method of claim 3, wherein the composite structure fluorescent ceramic having a controlled photothermal property is prepared by the steps of: preparing a precursor solution by dissolving a metal salt and a polymer in a solvent; preparing a precursor film by coating the precursor solution on a substrate; and preparing a composite structure fluorescent ceramic by sintering the precursor film. The preparation method of the fluorescent body slurry in step (2) is as follows: ①The mixed ceramic raw material powder of the phosphor a Ca3Sc2Si3O 12 :Ce 3+ - b YAG:Ce- c CaAlSiN3:Eu 2+ , 0.1≤ a ≤ 0.2, 0.075 ≤c≤ 0.15, b =1- a - c The mixed powder is prepared by stirring and mixing the light absorber Sudan 3, the photoinitiator TPO and the UV monomer and then drying, wherein the particle size of the mixed powder is 250nm-300nm, the weight ratio of the UV monomer to the mixed ceramic raw material powder is 10:1, the UV monomer is a mixture of hexanediol diacrylate and ethoxylated (5) pentaerythritol tetraacrylate with a mass ratio of 4:1; the dosages of the light absorber Sudan 3 and the photoinitiator TPO are both 0.4 wt %~1.5 wt % of the UV monomer; ②Dispersant ammonium citrate and PH regulator tetramethylammonium hydroxide are added to deionized water to prepare a fluorescent body structure premix solution; The amount of ammonium citrate is 0.35wt% and the amount of tetramethylammonium hydroxide is 1.2wt% based on the mass of the mixed powder in step 1; The raw material powder after drying in step 1 is added to the premixed solution of the phosphor structure in step 2 in four to five times, and the first time is 50% of the total mass of the raw material powder. After the raw material powder is added to the premixed solution, low-speed ball milling is performed, and then monomer acrylamide AM and N,N'-methylene bisacrylamide are added for low-speed ball milling. After ball milling, the slurry is deaerated to obtain a phosphor slurry stock solution with a solid content of 40vol% to 48vol%. The low-speed ball milling speed is 50-90r / min, the milling ball is high-purity alumina ball, and the mass ratio of the raw material powder to the high-purity alumina ball is 0.8:1.

9. The amount of monomer acrylamide AM added is 2.0wt% based on the mass of the raw material mixed powder, and the mass ratio of monomer acrylamide AM to N,N'-methylene bisacrylamide is 1:10 to 1:

12.

4. A catalyst tetramethyl ethylenediamine solution is added to the phosphor slurry stock solution obtained in step 3, stirred, and then an initiator ammonium persulfate solution is added and stirred uniformly to obtain a phosphor slurry. The prepared phosphor slurry has a solid content of 40vol% to 48vol%. The concentration of the tetramethyl ethylenediamine solution is 25wt%, the concentration of the ammonium persulfate solution is 8wt%, the addition amount of the tetramethyl ethylenediamine solution is 0.05-0.3vol% of the phosphor slurry stock solution, and the addition amount of the ammonium persulfate solution is 0.4-0.6vol% of the phosphor slurry stock solution.

6. The method for preparing composite fluorescent ceramics with regulated photothermal properties according to claim 3, characterized in that, The preparation method of the heat-conducting rod slurry of step (3) is as follows: ① 200 g of aluminum nitride and aluminum oxide mixed powder x Al2O3- y AlN, 0.25≤ x ≤0.75, y = 1-x is dispersed in 100 mL of anhydrous ethanol, and a light absorber Sudan red 3, a photoinitiator TPO, and a UV monomer are added and stirred to obtain a suspension; wherein the weight ratio of the UV monomer to the aluminum nitride and aluminum oxide mixed powder x Al2O3- y AlN is 10:1, and the UV monomer is a mixture of hexanediol diacrylate and ethoxylated (5) pentaerythritol tetraacrylate at a mass ratio of 4:1; 1-7 wt% of polymaleic anhydride HPMA is added to the above suspension based on the mass of the mixed powder; then the mixture is added to a ball mill tank, wherein the mass ratio of zirconia balls to the aluminum nitride and aluminum oxide mixed powder in the ball mill tank is 2:1, and the ball milling is carried out at a speed of 250 r / min for 12 h to obtain a completely dispersed and uniform mixed suspension; then the mixed suspension is centrifuged, filtered, washed, and dried in an oven for 12 h, with the oven temperature set to 55°C, to obtain a surface-modified aluminum oxide and aluminum nitride mixed powder; 2. The surface-modified alumina and aluminum nitride mixed powder is dispersed in deionized water to obtain a modified powder suspension, then a binder polyvinyl alcohol is added, the amount of the binder polyvinyl alcohol is 1-3wt% based on the weight of the modified powder suspension, and the pH value is adjusted to 7.0 by using NH3·H2O; 1-7wt% of polymaleic anhydride HPMA is added in the above suspension based on the mass of the surface-modified alumina and aluminum nitride mixed powder; then it is added into a ball mill tank, the mass ratio of zirconia balls to the mixed powder of aluminum nitride and alumina in the ball mill tank is 2:1, continuous ball milling is carried out at a speed of 250r / min for 2h, after adding plasticizer phthalic acid diester and defoaming agent, continuous ball milling is carried out at a speed of 250r / min for 2h, and finally a heat-conducting rod slurry with a solid content of 70-75% is obtained, wherein the defoaming agent is Datian Chemical GN-56, the amount of the plasticizer phthalic acid diester is 1wt% based on the weight of the modified powder suspension, and the amount of the defoaming agent is 0.2-1wt%.

7. The method for preparing composite fluorescent ceramics with regulated photothermal properties according to claim 3, characterized in that, The light-curing 3D printing technology direct-writing slurry preparation method of step (4) is as follows: ①The phosphor slurry, the heat conduction rod slurry and the outer skin layer slurry are respectively placed in the slurry storage box; ②The nozzle 1, 2 and 3 are set as three coordinate systems, the coordinate system of the nozzle 1 is translated along the x-axis with the center distance of the nozzle to obtain the coordinate system of the nozzle 2, and the coordinate system of the nozzle 2 is translated along the x-axis with the center distance of the nozzle to obtain the coordinate system of the nozzle 3; the fluorescent ceramic structure model is sliced, and the printing speed is set as 3 mm / s, the printing pressure range is 65-75 psi, the printing platform temperature is set as 30℃, and the printing layer slice thickness is 0.1 mm; the light-curing 3D printing technology is used for printing, the nozzle 1 prints an outer skin layer structure first, the nozzle 3 prints the heat conduction rod structure after solidification, and the nozzle 2 prints the phosphor structure of the fluorescent ceramic after solidification; the three nozzles are alternately used for printing, and the UV irradiation light-curing is performed layer by layer, and finally the composite ceramic body is obtained.

8. The method for preparing composite fluorescent ceramics with regulated photothermal properties according to claim 2, characterized in that, The operation process of step (5) is as follows: the organic matter in the element blank is discharged by sintering at 380℃-390℃ for 10h-12h and sintering at 700℃-800℃ for 6h-8h; the operation process of sintering in an argon atmosphere is as follows: sintering in an argon atmosphere at 1490℃-1510℃ for 10h-15h, and then cooling to room temperature.

9. Use of the composite structure fluorescent ceramic for regulating photothermal properties according to claim 1 in the field of fluorescent conversion type LD laser lighting, characterized in that, The outer skin layer is wrapped outside the phosphor, the cross-sectional area is 1%-3% of the cross-sectional area of the entire device, the number of heat conduction rods is controlled to be 35-44, and the total cross-sectional area of the heat conduction rods is controlled to be 16.67%-25% of the cross-sectional area of the device.

10. Use according to claim 9, characterized in that: When the composite structure fluorescent ceramic for regulating the photo-thermal performance is applied to the LD laser lighting device, the excitation source is blue light LD laser.

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