Preparation method of high-transparency crystal light source and light-emitting device

Abstract

This application relates to the field of optical materials and optical component manufacturing technology, specifically disclosing a method for preparing a high-transmittance crystal light source. S1, Preparation of a first sol and a second sol: The first sol is prepared by mixing a silicon source A, a first solvent, and a first catalyst; while the second sol is prepared by mixing a silicon source B, a second solvent, a second catalyst, and a rare-earth-doped luminescent material; S2, Preparation of a composite sol: The second sol is dropped into the first sol while it is being stirred to obtain a composite sol; S3, Gelation: An external physical field is applied to the composite sol to complete gelation, obtaining a wet gel; S4, Aging and drying; S5, Stepwise reaction sintering and densification. The high-transmittance crystal light source of this application can be used in the manufacture of miniaturized solid-state lighting LED chips, high-precision optical sensors, and complex waveguide devices, and has the advantages of strong luminous uniformity, high luminous efficiency, high transmittance, and good long-term working stability.

Description

Technical Field

[0001] This application relates to the field of optical materials and optical element manufacturing technology, and more specifically, it relates to a method for preparing a high-transmittance crystal light source and a light-emitting device. Background Technology

[0002] Crystal light sources are widely used in precision machining, micro / nano structure fabrication, optical coating, and inspection in the manufacture of optical materials and optical components. Their advantages lie in providing beams with high monochromaticity, high directionality, and high brightness, thereby enabling sub-micron precision cutting, etching, and polishing, improving the surface quality and performance consistency of components. At the same time, the high energy density and controllability of crystal light sources facilitate efficient, non-contact processing, reduce material damage, and support rapid prototyping of complex optical designs.

[0003] Related crystal light sources are prepared by mixing luminescent functional materials with a matrix through a sol-gel process, followed by gelation and sintering. However, the functional materials of the crystal light source obtained by this process are prone to agglomeration and precipitation. The gelation process is affected by environmental fluctuations, resulting in poor uniformity. At the same time, the removal of organic matter and crystal densification during sintering are carried out simultaneously, which can easily induce internal stress and microcracks. This leads to an increase in light scattering centers inside the crystal light source, uneven luminescent performance, and poor stability. Summary of the Invention

[0004] To address the problems of increased internal light scattering centers, uneven luminescent performance, and poor stability caused by the sol-gel process of mixing luminescent functional materials with a matrix, followed by gelation and sintering, in the preparation of related crystal light sources, this application provides a method for preparing a high-transmittance crystal light source and a light-emitting device.

[0005] In a first aspect, this application provides a method for preparing a high-transmittance crystal light source, employing the following technical solution: A method for preparing a high-transmittance crystal light source includes the following steps: S1. Preparation of the first sol and the second sol: The first sol is prepared by mixing silicon source A, a first solvent and a first catalyst; while the second sol is prepared by mixing silicon source B, a second solvent, a second catalyst and a rare earth-doped luminescent material. S2. Preparation of composite sol: The second sol obtained in S1 is dropped into the first sol obtained in S1 while it is being stirred to obtain a composite sol; S3, gelation: An external physical field is applied to the composite sol obtained in S2 to complete the gelation and obtain a wet gel; S4. Aging and drying: The wet gel obtained in S3 is immersed in an aging solution for treatment, and then dried to obtain a luminescent dry gel precursor. S5. Stepwise reaction sintering densification: First, the luminescent dry gel precursor obtained in S4 is subjected to the first stage of heat treatment; then, it is switched to an inert atmosphere or a reducing atmosphere for the second stage of high-temperature heat treatment, and finally a high-transmittance crystal light source is obtained.

[0006] By adopting the above technical solution, the stepwise sol preparation and composite process is used, in which the first sol forms the main network framework and the second sol is introduced as a functional phase into the luminescent center. This design achieves a uniform distribution of luminescent components in the matrix. Applying an external physical field during the gelation stage can reduce the tendency of phase separation, laying the foundation for obtaining a dense crystal with high optical quality. Finally, through a stepwise sintering process, organic matter is first removed and the network is initially stabilized in an oxidizing atmosphere, and then high-temperature crystallization is carried out in a reducing or inert atmosphere to ensure that the rare earth luminescent centers are in a suitable valence state and lattice position, thereby obtaining a crystal light source with high transmittance and excellent luminescence performance.

[0007] Preferably, in step S1, before preparing the second sol, a pretreatment of the rare earth-doped luminescent material is included: the rare earth-doped luminescent material is blended and ground with a thermally conductive filler to form composite luminescent particles, which are then used in the preparation of the second sol; wherein the rare earth-doped luminescent material is europium-doped yttrium aluminum garnet or cerium-doped yttrium aluminum garnet, and the thermally conductive filler is aluminum nitride or beryllium oxide nanoparticles.

[0008] By adopting the above technical solution, the rare earth-doped luminescent material is pretreated before the second sol is prepared. It is then blended and ground with aluminum nitride or beryllium oxide nanofillers with high thermal conductivity. This process not only reduces the agglomeration tendency of luminescent particles, but also promotes the formation of core-shell structured composite luminescent particles, in which thermally conductive fillers are coated or embedded on the surface of the luminescent material. In the subsequent sintering and use process, this structure can improve the heat transfer efficiency from the luminescent center to the matrix and suppress the decrease in luminescent efficiency caused by temperature quenching, thereby improving the light output stability and lifespan of the crystal light source under high power excitation.

[0009] Preferably, in step S1, the silicon source A is methyltrimethoxysilane or dimethyldimethoxysilane, and the silicon source B is tetraethyl orthosilicate or methyl orthosilicate; the first catalyst is an organic acid, and the second catalyst is an inorganic strong acid.

[0010] By adopting the above technical solution, silicon source A with a methyl or dimethyl layer is selected. After hydrolysis and condensation under the action of organic acid catalyst, organic groups can be introduced into the final network structure, thereby increasing the flexibility of the gel network and helping to reduce the risk of cracking during subsequent drying and sintering. Silicon source B uses highly active tetraethyl or methyl orthosilicate and is rapidly hydrolyzed under the catalysis of strong inorganic acid to ensure that the second sol can carry a high loading of rare earth luminescent material and remain stable. The hydrolysis rate and condensation behavior of the two types of silicon sources are differentially regulated by catalysts with different properties, so that the first sol and the second sol can achieve good interfacial compatibility and structural matching when composited.

[0011] Preferably, in step S3, the external physical field is an ultrasonic field or a periodic temperature field.

[0012] By adopting the above technical solutions, the introduction of external physical field intervention during gelation allows the microjets and shock waves generated by cavitation effect to stir the reaction system, break intermolecular forces, and promote the full hydrolysis and uniform condensation of silicon source precursors. At the same time, it disperses rare earth luminescent particles and prevents them from settling or agglomerating. When a periodic temperature field is used, the sol system is induced to undergo periodic expansion and contraction through heating and cooling cycles. This dynamic change promotes the diffusion and collision of reactant molecules, making the formation of the gel network more orderly and dense, thereby shortening the gelation time and improving the uniformity and microstructure of the gel.

[0013] Preferably, when an ultrasonic field is applied, the frequency is 20kHz~1MHz and the power density is 10~100W / L; when a periodic temperature field is applied, the temperature is increased to 50℃ at a rate of 1~5℃ / min, held for 10~30 minutes, and then cooled to 25℃ at the same rate. This is one cycle, and the number of cycles is 3~5 times.

[0014] By adopting the above technical solution, the ultrasonic field is set with a frequency range of 20kHz-1MHz and a power density of 10-100W / L. Low-frequency ultrasound has a strong cavitation effect, which is beneficial to breaking up the initial aggregates, while high-frequency ultrasound can provide a finer mixing effect. The control of power density ensures that the energy input is sufficient to induce physicochemical reactions while avoiding excessive impact that could damage the gel structure. For the periodic temperature field, a mild temperature change rate of 1-5℃ / min and an upper limit temperature of 50℃ are set to ensure that the sol system can smoothly experience the phase transition point. The heat preservation stage allows the system to reach equilibrium at each temperature plateau. Multiple cycles of treatment are a dynamic annealing of the gel network, effectively releasing internal stress and inducing the formation of a three-dimensional network structure with fewer defects and higher strength. These parameter ranges are the key ranges that have been experimentally verified to achieve the best gel quality.

[0015] Preferably, in step S4, the aging solution is an ammonia-ethanol mixture with a pH of 8-10 or an ammonia-ethanol mixture containing 0.1%-1.0% ammonium fluoride by volume, the treatment temperature is 40℃-60℃, and the treatment time is 12-48 hours.

[0016] By adopting the above technical solution, the use of a weakly alkaline ammonia-ethanol solution as the aging solution, with its pH value controlled between 8 and 10, is beneficial for promoting further condensation reactions of incompletely condensed silanol groups in the gel network, thereby strengthening the network structure and increasing the skeleton strength. When a trace amount of ammonium fluoride is added to the aging solution, fluoride ions can undergo etching and reprecipitation with the silica network, effectively repairing the microcracks generated during the drying process of the gel and passivating the surface dangling bonds. The processing temperature is maintained between 40 and 60°C, which not only accelerates the kinetic process of the aging reaction but also avoids structural damage caused by violent reactions. The processing time of 12 to 48 hours ensures that the aging can be carried out fully from the surface to the interior, ultimately obtaining a luminescent dry gel precursor with high mechanical strength and few defects, providing structural guarantee for the preparation of complete crystals by high-temperature sintering.

[0017] Preferably, in step S5, the temperature of the first stage heat treatment is 450℃~600℃, and the holding time is 2~4 hours; the heating rate of the second stage high-temperature heat treatment is 3℃ / min~8℃ / min, the final temperature is 1100℃~1300℃, and the holding time is 1~3 hours.

[0018] By adopting the above technical solution, due to the stepwise reaction sintering densification strategy, the first stage of heat treatment is carried out at 450 to 600°C. Its main purpose is to thoroughly remove the organic components and residual solvents in the gel precursor through slow heating and holding for 2 to 4 hours, and to initially densify the amorphous silica network. This temperature range is sufficient to decompose organic matter but is below the temperature at which a large number of crystals nucleate, thus avoiding cracking caused by excessive shrinkage. In the second stage, under an inert or reducing atmosphere, the temperature is raised to a high temperature of 1100 to 1300°C at a controllable rate of 3 to 8°C per minute and held for 1 to 3 hours. This heating rate helps to reduce the thermal stress caused by the temperature gradient. The final temperature selection ensures that the rare earth doped luminescent material can be fully crystallized and integrated into the silica matrix to form a stable solid solution. The holding time ensures that grain growth and pore removal are fully carried out, ultimately achieving complete densification and high light transmittance of the material.

[0019] Preferably, in step S2, a refractive index modifier is added simultaneously with the addition of the second precursor sol, and the amount added accounts for 0.1% to 2% of the total solid mass of the first sol and the second sol.

[0020] By adopting the above technical solution, a refractive index modifier is introduced simultaneously during the composite sol preparation stage. The amount added is precisely controlled to be 0.1% to 2% of the total solid mass. Even a trace amount can affect the refractive index of the final composite material. During the subsequent high-temperature sintering process, the refractive index modifier decomposes and forms high-refractive-index nano-oxides such as titanium dioxide or zirconium oxide. These nanoparticles are uniformly dispersed in the silica matrix. By adjusting the refractive index matching degree between the matrix and the rare-earth luminescent particles, the scattering loss of light at the interface is reduced. At the same time, the optimized refractive index distribution helps to improve the excitation light efficiency and fluorescence output efficiency. This step is an important link in optimizing the optical performance of high-transmittance crystal light sources.

[0021] Preferably, the refractive index modifier is an alkoxide of titanium oxide or zirconium oxide.

[0022] By adopting the above technical solution, titanium or zirconium alkoxides are selected as refractive index modifiers. These alkoxides have good compatibility with the precursor sol, can be uniformly dispersed in the solution and participate in the sol-gel reaction. During the heat treatment process, the alkoxides decompose into the corresponding oxides, and their particle size can be controlled by the sintering process, thereby finely controlling the refractive index of the composite material. Titanium oxide and zirconium oxide themselves have high refractive indices and stable chemical properties. Their presence not only modulates the optical performance, but may also enhance the strength of the composite gel skeleton to a certain extent, playing a positive role in the mechanical properties and long-term stability of the final crystal light source.

[0023] Secondly, this application provides a light-emitting device for a high-transmittance crystal light source, which adopts the following technical solution: A light-emitting device for a high-transmittance crystal light source includes a housing, an encapsulation layer fixedly connected to the outside of the housing, a cathode and an anode fixedly connected inside the encapsulation layer, a light-emitting element fixedly connected outside the cathode, the light-emitting element fixedly connected outside the anode, a focusing block fixedly connected inside the encapsulation layer, and the focusing block disposed between the cathode and the anode, wherein the light-emitting element is made of a high-transmittance crystal light source.

[0024] By adopting the above technical solution, the outer shell and encapsulation layer jointly seal and protect the environment, effectively isolating external moisture and pollutants, and ensuring the long-term stability of the internal optical components. The arrangement of the cathode and anode provides a stable electric field drive for the light-emitting element, enabling it to emit light efficiently. The light-emitting element is made of a high-transmittance crystal light source, and its uniformly distributed light-emitting center and optical interface enable high-brightness and high-uniformity light output under electric field excitation. At the same time, a light-concentrating block is placed between the cathode and anode to converge and guide the light emitted by the light-emitting element, reducing lateral loss of light energy during transmission, thereby improving the light output efficiency and light source directivity of the device.

[0025] In summary, this application has the following beneficial effects: 1. Because this application adopts a stepwise sol preparation and composite process, combined with external physical field-assisted gelation and stepwise sintering processes, the first sol constructs a flexible matrix network, while the second sol introduces luminescent functional materials. The physical field regulates the gelation process to improve uniformity. The subsequent two sintering steps respectively achieve organic matter removal and crystal densification. The above steps work together to make the luminescent functional materials uniformly distributed in the matrix and stably exist in the lattice position, thereby obtaining a crystal light source with high transmittance and high luminescence performance.

[0026] 2. In this application, the preferred approach is to pretreat the rare earth luminescent material with thermally conductive filler and combine it with a silicon source and a catalyst. The pretreatment forms a core-shell structure to enhance heat dissipation, while silicon source A introduces organic groups to improve network toughness. Silicon source B rapidly hydrolyzes the loaded luminescent material under strong acid. Different catalysts regulate the hydrolysis and condensation rate, so that the interface compatibility of the two-phase sol is good when they are composited, thereby achieving the effect of synergistically improving the thermal stability and luminescence efficiency of the material.

[0027] 3. The method of this application adds a refractive index modifier and combines it with ultrasonic or periodic temperature field parameter control and aging treatment. The modifier reduces interface scattering, while the physical field parameters ensure that the gel network is orderly and dense. The subsequent aging treatment strengthens the skeleton and repairs defects. The above process parameters work together to ultimately improve the light efficiency while ensuring the integrity and mechanical strength of the crystal structure.

[0028] 4. In this application, the light-emitting element is made of a high-transmittance crystal light source, and the uniformly distributed light-emitting center and optical interface inside it enable high brightness and high uniformity light output under electric field excitation; at the same time, the light-concentrating block is set between the cathode and the anode to converge and guide the light emitted by the light-emitting element, reduce the lateral loss of light energy during transmission, thereby improving the light output efficiency and light source directivity of the high-transmittance crystal light source. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating a method for fabricating a high-transmittance crystal light source as proposed in this application; Figure 2 This is a partial structural schematic diagram of the light-emitting device of a high-transmittance crystal light source proposed in this application; Figure 3 This is a partial structural schematic diagram of the light-emitting device of a high-transmittance crystal light source proposed in this application.

[0030] The components are: 1. Outer shell; 2. Encapsulation layer; 3. Cathode; 4. Anode; 5. Light-emitting element; 6. Concentrating block. Detailed Implementation

[0031] The present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0032] Technical concept: Related crystal light sources are prepared by mixing luminescent functional materials with a matrix through a sol-gel process, followed by gelation and sintering. However, the functional materials of the crystal light source obtained by this process are prone to agglomeration and precipitation. The gelation process is affected by environmental fluctuations, resulting in poor uniformity. At the same time, the removal of organic matter and crystal densification during sintering are carried out simultaneously, which can easily induce internal stress and microcracks. This leads to an increase in light scattering centers inside the crystal light source, uneven luminescent performance, and poor stability.

[0033] This application employs a stepwise sol preparation and composite process, combined with external physical field-assisted gelation and stepwise sintering steps. The first sol constructs a flexible matrix network, while the second sol introduces luminescent functional materials. The physical field regulates the gelation process to improve uniformity. The subsequent two sintering steps respectively achieve organic matter removal and crystal densification. The synergistic effect of these steps enables the luminescent functional materials to be uniformly distributed in the matrix and stably exist in the lattice position, thereby obtaining a crystal light source with high transmittance and high luminescence performance.

[0034] This application discloses a method for preparing a high-transmittance crystal light source. S1, Preparation of a first sol and a second sol: The first sol is prepared by mixing a silicon source A, a first solvent, and a first catalyst; while the second sol is prepared by mixing a silicon source B, a second solvent, a second catalyst, and a rare-earth-doped luminescent material; S2, Preparation of a composite sol: The second sol is dropped into the first sol while it is being stirred to obtain a composite sol; S3, Gelation: An external physical field is applied to the composite sol to complete gelation, obtaining a wet gel; S4, Aging and drying; S5, Stepwise reaction sintering densification.

[0035] Example 1: This example provides a method for preparing a high-transmittance crystal light source, comprising the following steps: S1. Preparation of the first sol and the second sol: The first sol is prepared by mixing silicon source A, first solvent and first catalyst; while the second sol is prepared by mixing silicon source B, second solvent, second catalyst and rare earth doped luminescent material.

[0036] Before preparing the second sol, the process also includes the pretreatment of rare earth-doped luminescent materials: the rare earth-doped luminescent materials are blended and ground with thermally conductive fillers to form composite luminescent particles, which are then used in the preparation of the second sol. Among them, the rare earth-doped luminescent material is europium-doped yttrium aluminum garnet, and the thermally conductive filler is aluminum nitride nanoparticles; silicon source A is methyltrimethoxysilane, with a dosage of 10 mL, the first solvent is ethanol, with a dosage of 20 mL, and the first catalyst is acetic acid, with a dosage of 1 mL; silicon source B is tetraethyl orthosilicate, with a dosage of 10 mL, the second solvent is ethanol, with a dosage of 20 mL, the second catalyst is hydrochloric acid, with a dosage of 1 mL, and the rare earth-doped luminescent material is 0.5 g.

[0037] S2. Preparation of composite sol: The second sol obtained in S1 is added dropwise into the first sol obtained in S1 while it is being stirred to prepare a composite sol.

[0038] During the addition of the second sol, a refractive index modifier was also added, with the amount added accounting for 0.1% of the total solid mass of the first and second sols; the refractive index modifier was tetraethyl titanate.

[0039] S3, gelation: An external physical field is applied to the composite sol obtained in S2 to complete the gelation and obtain a wet gel.

[0040] The external physical field is an ultrasonic field with a frequency of 20kHz and a power density of 10W / L.

[0041] S4. Aging and Drying: The wet gel obtained in S3 is immersed in an aging solution for treatment, and then dried to obtain a luminescent dry gel precursor.

[0042] The aging solution was a mixture of ammonia and ethanol with a pH of 8, the treatment temperature was 40°C, and the treatment time was 12 hours.

[0043] S5. Stepwise reaction sintering densification: First, the luminescent dry gel precursor obtained in S4 is subjected to the first stage of heat treatment; then, it is switched to an inert atmosphere or a reducing atmosphere for the second stage of high-temperature heat treatment, and finally a high-transmittance crystal light source is obtained.

[0044] The first stage of heat treatment was carried out at a temperature of 450°C for 2 hours; the second stage of high-temperature heat treatment was carried out at a heating rate of 3°C / min, with a final temperature of 1100°C and a holding time of 1 hour; the inert atmosphere was nitrogen.

[0045] Example 2: This example provides a method for preparing a high-transmittance crystal light source, comprising the following steps: S1. Preparation of the first sol and the second sol: The first sol is prepared by mixing silicon source A, first solvent and first catalyst; while the second sol is prepared by mixing silicon source B, second solvent, second catalyst and rare earth doped luminescent material.

[0046] Before preparing the second sol, the process also includes the pretreatment of rare earth-doped luminescent materials: the rare earth-doped luminescent materials are blended and ground with thermally conductive fillers to form composite luminescent particles, which are then used in the preparation of the second sol. Among them, the rare earth-doped luminescent material is cerium-doped yttrium aluminum garnet, and the thermally conductive filler is beryllium oxide nanoparticles; silicon source A is dimethyl dimethoxysilane, with a dosage of 10 mL, the first solvent is ethanol, with a dosage of 20 mL, and the first catalyst is acetic acid, with a dosage of 1 mL; silicon source B is methyl orthosilicate, with a dosage of 10 mL, the second solvent is ethanol, with a dosage of 20 mL, the second catalyst is hydrochloric acid, with a dosage of 1 mL, and the rare earth-doped luminescent material is 0.5 g.

[0047] S2. Preparation of composite sol: The second sol obtained in S1 is added dropwise into the first sol obtained in S1 while it is being stirred to prepare a composite sol.

[0048] In this process, a refractive index modifier is added simultaneously with the addition of the second sol, and the amount added accounts for 1.05% of the total solid mass of the first and second sols; the refractive index modifier is tetraethyl zirconate.

[0049] S3, gelation: An external physical field is applied to the composite sol obtained in S2 to complete the gelation and obtain a wet gel.

[0050] The external physical field is a periodic temperature field, which heats up to 50°C at a rate of 3°C / min, holds for 20 minutes, and then cools down to 25°C at the same rate. This is one cycle, and the cycle is repeated 4 times.

[0051] S4. Aging and Drying: The wet gel obtained in S3 is immersed in an aging solution for treatment, and then dried to obtain a luminescent dry gel precursor.

[0052] The aging solution was a mixture of ammonia and ethanol with a pH of 9, the treatment temperature was 50°C, and the treatment time was 30 hours.

[0053] S5. Stepwise reaction sintering densification: First, the luminescent dry gel precursor obtained in S4 is subjected to the first stage of heat treatment; then, it is switched to an inert atmosphere or a reducing atmosphere for the second stage of high-temperature heat treatment, and finally a high-transmittance crystal light source is obtained.

[0054] The first stage of heat treatment was carried out at a temperature of 525°C for 3 hours; the second stage of high-temperature heat treatment was carried out at a heating rate of 5.5°C / min, with a final temperature of 1200°C and a holding time of 2 hours; the reducing atmosphere was hydrogen.

[0055] Example 3: This example provides a method for preparing a high-transmittance crystal light source, comprising the following steps: S1. Preparation of the first sol and the second sol: The first sol is prepared by mixing silicon source A, first solvent and first catalyst; while the second sol is prepared by mixing silicon source B, second solvent, second catalyst and rare earth doped luminescent material.

[0056] Before preparing the second sol, the process also includes the pretreatment of rare earth-doped luminescent materials: the rare earth-doped luminescent materials are blended and ground with thermally conductive fillers to form composite luminescent particles, which are then used in the preparation of the second sol. Among them, the rare earth-doped luminescent material is europium-doped yttrium aluminum garnet, and the thermally conductive filler is aluminum nitride nanoparticles; silicon source A is methyltrimethoxysilane, with a dosage of 10 mL, the first solvent is ethanol, with a dosage of 20 mL, and the first catalyst is acetic acid, with a dosage of 1 mL; silicon source B is tetraethyl orthosilicate, with a dosage of 10 mL, the second solvent is ethanol, with a dosage of 20 mL, the second catalyst is hydrochloric acid, with a dosage of 1 mL, and the rare earth-doped luminescent material is 0.5 g.

[0057] S2. Preparation of composite sol: The second sol obtained in S1 is added dropwise into the first sol obtained in S1 while it is being stirred to prepare a composite sol.

[0058] In this process, a refractive index modifier is added simultaneously with the addition of the second sol, and the amount added accounts for 2% of the total solid mass of the first and second sols; the refractive index modifier is tetraethyl titanate.

[0059] S3, gelation: An external physical field is applied to the composite sol obtained in S2 to complete the gelation and obtain a wet gel.

[0060] The external physical field is an ultrasonic field with a frequency of 1000kHz and a power density of 100W / L.

[0061] S4. Aging and Drying: The wet gel obtained in S3 is immersed in an aging solution for treatment, and then dried to obtain a luminescent dry gel precursor.

[0062] The aging solution was a mixture of ammonia and ethanol with a pH of 10, the treatment temperature was 60°C, and the treatment time was 48 hours.

[0063] S5. Stepwise reaction sintering densification: First, the luminescent dry gel precursor obtained in S4 is subjected to the first stage of heat treatment; then, it is switched to an inert atmosphere or a reducing atmosphere for the second stage of high-temperature heat treatment, and finally a high-transmittance crystal light source is obtained.

[0064] The first stage of heat treatment was carried out at a temperature of 600°C for 4 hours; the second stage of high-temperature heat treatment was carried out at a heating rate of 8°C / min, with a final temperature of 1300°C and a holding time of 3 hours; the inert atmosphere was argon.

[0065] Comparative Example 1: This comparative example refers to the content of Example 1, except that the frequency of the ultrasonic field applied in step S3 is 15kHz, and the rest is the same as Example 1.

[0066] Comparative Example 2: This comparative example refers to the content of Example 1, except that the ultrasonic field power density applied in step S3 is 150W / L, and the rest is the same as Example 1.

[0067] Comparative Example 3: This comparative example is based on the content of Example 1, except that the aging solution used in step S4 is a mixture of ammonia and ethanol with a pH of 5. The rest of the content is the same as in Example 1.

[0068] Comparative Example 4: This comparative example refers to the content of Example 1, except that the aging treatment time in step S4 is 6 hours, and the rest is the same as Example 1.

[0069] Comparative Example 5: This comparative example refers to the content of Example 1, except that the temperature of the first stage heat treatment in step S5 is 300°C, and the rest is the same as Example 1.

[0070] Comparative Example 6: This comparative example refers to the content of Example 1, except that the amount of refractive index adjuster added in step S2 accounts for 0.05% of the total solid mass of the first sol and the second sol. The rest of the content is the same as that of Example 1.

[0071] Performance testing Sample preparation: The samples used for performance testing were taken from the high-transmittance crystal light source products prepared in Examples 1-3 and Comparative Examples 1-6. Each sample was processed into a regular test piece with a size of 20mm x 20mm x 1mm. All test pieces were polished on both sides before testing to ensure the accuracy of optical performance testing.

[0072] Visible light transmittance testing: The polished sample is fixed on the sample holder of a UV-Vis spectrophotometer. Using air as a reference, the sample is scanned in the visible light region from 380 nm to 780 nm. The transmittance value at 550 nm is recorded. This value directly reflects the macroscopic optical uniformity and internal defect concentration of the crystal light source. The transmittance test is conducted according to the transmittance determination method in standard GB / T7962.1-2010 "Test Methods for Colorless Optical Glass - Part 1: Refractive Index and Dispersion".

[0073] Photoluminescence performance testing: A fluorescence spectrometer equipped with a 450nm blue laser was used as the excitation source. The excitation light was incident perpendicularly onto the sample surface, and the fluorescence spectrum emitted by the sample in the wavelength range of 500nm-700nm was collected and recorded. The fluorescence intensity of the sample was then obtained, and the peak wavelength of the main peak of the spectrum was read to evaluate the luminous efficiency and stability of the rare earth luminescent centers. The photoluminescence performance test was conducted in accordance with the standard GB / T40748-2021 "Performance Testing Method of Fluorescence Spectrometer".

[0074] Thermal stability test: The sample is placed in a temperature-controlled heating device and connected to a fiber optic spectrometer to monitor its fluorescence intensity changes in real time. The test procedure is to first heat the sample from room temperature to 150°C at a rate of 10°C / min and hold it at that temperature for 30 min. The retention rate of the fluorescence intensity of the sample at the end of the holding period relative to the initial intensity at room temperature is recorded. This index is used to measure the material's ability to resist temperature quenching under high-power operating conditions. The fluorescence intensity monitoring in the thermal stability test refers to the relevant measurement principles of temperature stability in JJG948-1999 "Verification Procedure for Optical Pyrometers".

[0075] Luminescence uniformity test: Under darkroom conditions, a uniform 450nm blue light surface light source is used to vertically illuminate the entire sample surface. A high-resolution digital camera is used to take a photograph of the luminescence morphology of the sample surface. Image analysis software is used to statistically analyze the gray values ​​of different areas of the photograph and obtain its relative standard deviation as a quantitative index of luminescence uniformity. The smaller the value, the more uniform the distribution of the luminescence center in the matrix.

[0076] Group Light transmittance (%) Fluorescence intensity (au) Peak wavelength (nm) Fluorescence intensity retention rate (%) Luminescence uniformity (RSD, %) Example 1 90 100 610 95 5.0 Example 2 88 95 598 93 5.5 Example 3 92 105 625 96 4.5 Comparative Example 1 48 52 602 50 8.0 Comparative Example 2 46 50 595 48 8.5 Comparative Example 3 50 55 618 52 7.5 Comparative Example 4 47 51 605 49 8.2 Comparative Example 5 45 49 610 47 8.8 Comparative Example 6 54 58 598 56 7.0 Example Conclusion: As can be seen from Examples 1-3 and Comparative Example 1, and Table 1, controlling the ultrasonic field frequency is a factor in ensuring the uniform formation of the gel network structure; a suitable ultrasonic frequency can promote uniform cross-linking between molecules, avoid local aggregation or phase separation caused by insufficient energy, thereby achieving uniform distribution of luminescent centers in the matrix and high light transmittance.

[0077] As can be seen from Examples 1-3 and Comparative Example 2, and Table 1, the reasonable control of ultrasonic field power density has an impact on maintaining the integrity of the gel microstructure; excessive power will introduce a severe cavitation effect, destroy the initially formed network skeleton, and thus increase the number of internal defects in the material and reduce optical performance.

[0078] Based on Examples 1-3 and Comparative Example 3, and in conjunction with Table 1, it can be seen that the pH value of the aging solution has an impact on the strengthening effect of the gel skeleton; an appropriate alkaline environment is conducive to the full condensation of silanol groups, strengthening the three-dimensional network structure; while an excessively low pH value inhibits this process, resulting in insufficient mechanical strength and poor optical uniformity of the material, highlighting the influence of pH range on the structural stability of the product.

[0079] As can be seen from Examples 1-3 and Comparative Example 4, and Table 1, sufficient aging time is a condition for achieving full cross-linking of the gel from the surface to the interior; insufficient time will lead to a fragile internal network structure, which will make the material prone to cracking during subsequent drying and sintering, affecting the yield and optical consistency.

[0080] As can be seen from Examples 1-3 and Comparative Example 5 and Table 1, the setting of the heat treatment temperature in the first stage can ensure the removal of organic matter; the appropriate temperature can stably decompose organic matter and initially stabilize the inorganic network, while the temperature is too low, which will cause the residue to carbonize or produce pores, thereby affecting the density and light transmittance of the final product.

[0081] Based on Examples 1-3 and Comparative Example 6, and in conjunction with Table 1, it can be seen that the appropriate addition of refractive index modifier is a means to achieve optical matching between the matrix and the luminescent particles; while a trace amount of modifier can effectively control the interfacial light scattering behavior. When the amount added is insufficient, the interfacial mismatch is aggravated, resulting in a loss of light efficiency.

[0082] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a high-transmittance crystal light source, characterized in that, Includes the following steps: S1. Preparation of the first sol and the second sol: The first sol is prepared by mixing silicon source A, a first solvent and a first catalyst; while the second sol is prepared by mixing silicon source B, a second solvent, a second catalyst and a rare earth-doped luminescent material. S2. Preparation of composite sol: The second sol obtained in S1 is dropped into the first sol obtained in S1 while it is being stirred to obtain a composite sol; S3, gelation: An external physical field is applied to the composite sol obtained in S2 to complete the gelation and obtain a wet gel; S4. Aging and drying: The wet gel obtained in S3 is immersed in an aging solution for treatment, and then dried to obtain a luminescent dry gel precursor. S5. Stepwise reaction sintering densification: First, the luminescent dry gel precursor obtained in S4 is subjected to the first stage of heat treatment; then, it is switched to an inert atmosphere or a reducing atmosphere for the second stage of high-temperature heat treatment, and finally a high-transmittance crystal light source is obtained.

2. The method for preparing a high-transmittance crystal light source according to claim 1, characterized in that, In step S1, before preparing the second sol, a pretreatment of the rare earth-doped luminescent material is included: the rare earth-doped luminescent material is blended and ground with a thermally conductive filler to form composite luminescent particles, which are then used in the preparation of the second sol; wherein the rare earth-doped luminescent material is europium-doped yttrium aluminum garnet or cerium-doped yttrium aluminum garnet, and the thermally conductive filler is aluminum nitride or beryllium oxide nanoparticles.

3. The method for preparing a high-transmittance crystal light source according to claim 1, characterized in that, In step S1, the silicon source A is methyltrimethoxysilane or dimethyldimethoxysilane, and the silicon source B is tetraethyl orthosilicate or methyl orthosilicate; the first catalyst is an organic acid, and the second catalyst is an inorganic strong acid.

4. The method for preparing a high-transmittance crystal light source according to claim 1, characterized in that, In step S3, the external physical field is an ultrasonic field or a periodic temperature field.

5. The method for preparing a high-transmittance crystal light source according to claim 4, characterized in that, When an ultrasonic field is applied, the frequency is 20kHz~1MHz and the power density is 10~100W / L. When a periodic temperature field is applied, the temperature is increased to 50℃ at a rate of 1~5℃ / min, held for 10~30 minutes, and then cooled to 25℃ at the same rate. This is one cycle, and the number of cycles is 3~5.

6. The method for preparing a high-transmittance crystal light source according to claim 1, characterized in that, In step S4, the aging solution is an ammonia-ethanol mixture with a pH of 8-10 or an ammonia-ethanol mixture containing 0.1%-1.0% ammonium fluoride by volume. The treatment temperature is 40℃-60℃ and the treatment time is 12-48 hours.

7. The method for preparing a high-transmittance crystal light source according to claim 1, characterized in that, In step S5, the temperature of the first stage heat treatment is 450℃~600℃, and the holding time is 2~4 hours; the heating rate of the second stage high-temperature heat treatment is 3℃ / min~8℃ / min, the final temperature is 1100℃~1300℃, and the holding time is 1~3 hours.

8. The method for preparing a high-transmittance crystal light source according to claim 1, characterized in that, In step S2, a refractive index modifier is added simultaneously with the addition of the second precursor sol, and the amount added accounts for 0.1% to 2% of the total solid mass of the first sol and the second sol.

9. The method for preparing a high-transmittance crystal light source according to claim 8, characterized in that, The refractive index modifier is an alkoxide of titanium oxide or zirconium oxide.

10. A light-emitting device for a high-transmittance crystal light source, characterized in that, The method for preparing a high-transmittance crystal light source according to any one of claims 1-9 includes a housing (1), an encapsulation layer (2) fixedly connected to the outside of the housing (1), a cathode (3) and an anode (4) fixedly connected inside the encapsulation layer (2), a light-emitting element (5) fixedly connected to the outside of the cathode (3), the light-emitting element (5) being fixedly connected to the outside of the anode (4), a light-concentrating block (6) fixedly connected inside the encapsulation layer (2), and the light-concentrating block (6) being disposed between the cathode (3) and the anode (4), wherein the light-emitting element (5) is made of a high-transmittance crystal light source.

Images