Fluorescent glass and preparation method and application thereof

Abstract

The application discloses Ce:YAG fluorescent glass as well as a preparation method and application thereof, belongs to the technical field of rare earth luminescent materials, and solves the problems of serious interface corrosion, and decreased luminous efficiency and thermal stability caused by insufficient matching degree between a fluorescent glass matrix material and fluorescent powder in the prior art. The fluorescent glass comprises a glass matrix and Y3Al5O 12 :Ce fluorescent powder; wherein the glass matrix comprises, in terms of molar percentage, 45-55mol% of SiO2, 15-25mol% of Al2O3, 1-10mol% of NaF, 1-10mol% of Na2O, 2-12mol% of MgO, 3-13mol% of CaO and 1-10mol% of K2O. The application has the advantages of relatively low reaction temperature, small energy consumption, no need of complex equipment, loose and cheap material selection, and wide application in the fields of illumination, display and optical devices, etc.

Description

Technical Field

[0001] This invention relates to the field of rare earth luminescent materials technology, and in particular to a fluorescent glass, its preparation method, and its application. Background Technology

[0002] White light-emitting diodes (WLEDs), as a new type of solid-state light source, have been widely used in indicator lighting, backlighting displays, automotive headlights, and general lighting due to their significant advantages such as long lifespan, small size, energy saving, environmental friendliness, and zero pollution. They are gradually replacing traditional incandescent and fluorescent lamps. Currently, commercial WLEDs mainly use a combination of blue InGaN chips and yellow Ce:YAG phosphors, encapsulated with organic resins or silicone. However, in high-power applications, the low thermal conductivity and poor thermal stability of the encapsulation materials lead to heat accumulation and temperature rise in the chip, resulting in problems such as decreased luminous efficiency and color coordinate drift, seriously damaging the long-term reliability of the device. The core bottleneck lies in the fact that the encapsulation materials are difficult to effectively conduct heat and are prone to aging and yellowing at high temperatures, ultimately causing light output attenuation and color inaccuracy.

[0003] Therefore, improving the thermal conductivity and thermal stability of encapsulation materials has become crucial to overcoming the performance bottlenecks in high-power WLED applications. Developing novel inorganic color conversion materials is currently the main research approach, such as transparent fluorescent ceramics (TCs), fluorescent glass ceramics (GCs), fluorescent glass (PiG), and fluorescent thin films (PiF), which have become key directions for improving WLED performance. These materials possess excellent thermal conductivity, chemical stability, and high-temperature tolerance, significantly enhancing long-term reliability while improving device color gamut coverage and brightness. However, these materials still suffer from issues such as blue light leakage under blue light excitation due to uneven phosphor distribution and excessively high local concentrations, insufficient thermal stability, and poor optical performance, hindering their further development in the WLED lighting field. For example, the high-temperature sintering process (>700℃) required for traditional substrates erodes the lattice of YAG:Ce phosphors, damaging the luminescent centers and leading to a decrease in quantum efficiency. Secondly, there is poor thermal and optical matching. The mismatch in the coefficients of thermal expansion between the two can easily introduce internal stress and cracking risks. At the same time, the high-temperature process required to achieve matrix densification often conflicts with the thermal stability requirements of phosphors, easily resulting in products with many pores and strong scattering, affecting luminous efficiency and uniformity. These factors together lead to the inherent defects of traditional fluorescent glass, such as low luminous efficiency, poor thermal stability, and poor optical uniformity.

[0004] In summary, although research on Ce:YAG fluorescent glass in WLED lighting is relatively mature, its practical application still faces challenges. Existing fluorescent glass materials mainly suffer from defects such as low luminous efficiency and poor stability. Therefore, developing Ce:YAG fluorescent glass with high-efficiency luminescence properties that can be excited by blue light has significant theoretical and practical value in promoting the application of semiconductor solid-state lighting sources in WLED lighting. Summary of the Invention

[0005] In view of the above, the present invention aims to provide a fluorescent glass and its preparation method and application, so as to solve at least one of the problems existing in the prior art: (1) the quantum efficiency of traditional fluorescent glass is low and the stability is poor; (2) in traditional fluorescent glass, the glass matrix is ​​easy to erode the phosphor, resulting in low color rendering index and luminous efficiency of the prepared WLED device.

[0006] The objective of this invention is mainly achieved through the following technical solutions:

[0007] The first aspect of this invention provides a fluorescent glass, the fluorescent glass comprising a glass matrix and Y3Al5O 12 Ce phosphor; The glass matrix comprises, by molar percentage: 45-55 mol% SiO2, 15-25 mol% Al2O3, 1-10 mol% NaF, 1-10 mol% Na2O, 2-12 mol% MgO, 3-13 mol% CaO, and 1-10 mol% K2O.

[0008] Furthermore, the glass matrix comprises, by molar percentage: 48-52 mol% SiO2, 18-22 mol% Al2O3, 4-6 mol% NaF, 4-6 mol% Na2O, 6-8 mol% MgO, 7-9 mol% CaO, and 4-6 mol% K2O.

[0009] Furthermore, in the fluorescent glass, the mass percentage of the phosphor is 10~60wt%.

[0010] Furthermore, in the fluorescent glass, the mass percentage of the phosphor is 40-50 wt%.

[0011] A second aspect of the present invention provides a method for preparing the fluorescent glass described in the first aspect, comprising: S1. SiO2, Al2O3, NaF, Na2O, MgO, CaO and K2O are mixed evenly and then melted to obtain a molten liquid. After cooling, glass powder is obtained. S2, mix the glass powder and Y3Al5O 12Ce phosphor is mixed evenly and then sintered to obtain fluorescent glass.

[0012] Furthermore, the sintering conditions include: heating to 600-650°C at a heating rate of 2-10°C / min, and sintering for 10-50 min.

[0013] Furthermore, the method also includes grinding the cooled glass matrix to 10-15 micrometers.

[0014] Furthermore, the method further includes: cutting the obtained fluorescent glass into thin slices with a thickness of 0.2 mm to 1.25 mm and polishing them.

[0015] A third aspect of the present invention provides a WLED lighting device comprising the fluorescent glass described in the first aspect.

[0016] The fourth aspect of this invention provides the application of the fluorescent glass described in the first aspect or the fluorescent glass prepared by the preparation method described in the second aspect in WLED lighting devices.

[0017] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: (1) This invention, through a specific NaF-silicate glass system, endows fluorescent glass with higher chemical stability, effectively inhibiting the erosion of phosphor by the glass matrix. At the same time, the introduction of fluoride ions significantly reduces the sintering temperature in the preparation process, allowing the fluorescent glass to be sintered at a lower temperature, thus protecting commercial Ce:YAG phosphor (i.e., Y3Al5O3). 12 The crystal structure and luminescent activity of Ce phosphor (Ce phosphor) are investigated. Its all-inorganic properties solve the problem of high-temperature yellowing and aging of silicone phosphors, and its higher thermal conductivity can effectively reduce the LED junction temperature and suppress phosphor thermal quenching.

[0018] (2) In the presence of a specific glass matrix, this invention successfully achieved a wide color temperature adjustment range of 3000~6000K by precisely controlling the phosphor doping ratio (10%~60%) and the thickness of the fluorescent glass (0.2~1.25mm). Simultaneously, the optimized low-temperature sintering process maximizes the protection of the Ce:YAG phosphor's crystal structure; for example, in Example 5, the internal quantum efficiency of the fluorescent glass reaches 85.1%, and the external quantum efficiency reaches 55.6%. The final luminous efficiency is stable between 119~150 lumens / watt, simultaneously meeting diverse application scenarios such as warm white light (3000K) required for home lighting and cool white light (6000K) required for commercial lighting, providing reliable technical support for achieving high-quality, customizable solid-state lighting solutions.

[0019] (3) The present invention adopts a low-temperature co-sintering process, which mixes glass powder with commercially available Y3Al5O12 Ce:YAG fluorescent glass is formed by mixing Ce phosphors and sintering at 600~650℃. The preparation process is simple, stable and controllable, and low in cost, which gives it a cost advantage and facilitates large-scale production and market promotion. Attached Figure Description

[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0021] Figure 1 The XRD patterns are those of the fluorescent glass in Examples 1-6 of this invention.

[0022] Figure 2 The images show the excitation and emission spectra of the fluorescent glass in Example 5 of this invention.

[0023] Figure 3 The images show the emission spectra of fluorescent glasses with different phosphor doping amounts in Examples 1-6 of this invention.

[0024] Figure 4 The transmittance spectra of fluorescent glasses with different phosphor doping amounts in Examples 1-6 of this invention are shown.

[0025] Figure 5 The fluorescent glass of the present invention exhibits emission spectra at different sintering temperatures.

[0026] Figure 6 The emission spectra of phosphor and fluorescent glass in the fluorescent glass of Example 5 of the present invention are shown at different test temperatures.

[0027] Figure 7 This is a comparison diagram of the EQE and IQE of fluorescent glass and phosphor in Embodiment 5 of the present invention.

[0028] Figure 8 This is a fluorescence lifetime curve of the fluorescent glass and phosphor in Example 5 of the present invention. Detailed Implementation

[0029] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0030] Due to the inherent poor thermal reliability and easy aging problems of traditional organic encapsulation (silicone) in existing technologies, and the problems of inorganic fluorescent materials (such as existing PiG, GCs, etc.) as alternatives, such as low luminous efficiency, easy blue light leakage, complex preparation process, or damage (corrosion) to phosphors, the first aspect of this invention provides a fluorescent glass, which includes a glass matrix and Y3Al5O12 Ce phosphor; The glass matrix comprises, by molar percentage: 45-55 mol% SiO2, 15-25 mol% Al2O3, 1-10 mol% NaF, 1-10 mol% Na2O, 2-12 mol% MgO, 3-13 mol% CaO, and 1-10 mol% K2O.

[0031] In this invention, the above-mentioned components work synergistically to ensure the chemical stability of the fluorescent glass, effectively prevent the glass components from corroding the Ce:YAG phosphor, and improve the luminous efficiency.

[0032] Specifically, the SiO2 content of no less than 45 mol% provides a stable structural framework for the fluorescent glass and significantly enhances its overall chemical stability, effectively preventing the glass components from corroding the Ce:YAG phosphor. Al2O3, as a network intermediate, further improves the mechanical strength and chemical durability of the glass. Fluoride ions in NaF can break Si-O-Si bonds and form Si-F bonds, thereby significantly reducing the melting temperature, viscosity, and glass transition temperature of the glass. This allows subsequent processes to achieve sintering at a lower temperature of 640℃, avoiding damage to the phosphor at high temperatures. Na2O and K2O, together with NaF, act as fluxing agents, further reducing the softening point of the system. At the same time, the addition of MgO and CaO effectively suppresses the tendency of the glass to crystallize during heat treatment and further improves the chemical stability of the material. Together, they ensure the structural stability of the final composite material at high temperatures and improve the quenching temperature of the product. Specifically, the luminescence intensity retention rate at 175℃ is no less than 78%, preferably no less than 83%.

[0033] Furthermore, considering effective resistance to erosion of Ce:YAG phosphor, the SiO2 content is 45-55 mol%. If it is less than 45 mol%, the network structure of the glass matrix is ​​incomplete, leading to a sharp decrease in the chemical stability of the fluorescent glass. The glass matrix also becomes too soft and has low viscosity during subsequent sintering, causing phosphor sedimentation or glass matrix deformation, and increasing the risk of phosphor erosion. If it is greater than 55 mol%, the melting temperature, viscosity, and transition temperature of the glass matrix will increase significantly. This results in insufficient densification during sintering at lower target sintering temperatures, leading to porosity, reduced light transmittance and mechanical strength, and thus reduced luminous efficiency. For example, the SiO2 content is 45 mol%, 48 mol%, 49 mol%, 50 mol%, 52 mol%, 53 mol%, 55 mol%, or any combination of two of these values.

[0034] Considering the good compatibility with Ce:YAG phosphor and the enhancement of the glass network, the Al2O3 content is 15-25 mol%. If it is less than 15 mol%, the network structure strength of the glass matrix is ​​insufficient, leading to further deterioration of chemical stability, weakened protection of the phosphor, and increased susceptibility to phase separation in the glass matrix. If it is greater than 25 mol%, the network structure of the glass matrix will be unstable, and the viscosity of the glass will increase significantly, making subsequent melting and densification sintering at the target sintering temperature difficult. For example, the Al2O3 content is 15 mol%, 18 mol%, 19 mol%, 20 mol%, 22 mol%, 23 mol%, 25 mol%, or any combination of two of the above values.

[0035] To achieve the crucial low-temperature sintering and adjust the glass network, the NaF concentration is 1-10 mol%. If it is less than 1 mol%, its effect on breaking Si-O-Si bonds, reducing glass viscosity, and lowering the transition temperature is not significant, leading to a higher sintering temperature and failing to achieve the goal of low-temperature sintering to protect the phosphor. If it is greater than 10 mol%, the excess F... - This can make the glass network too fragile, leading to a significant decrease in chemical stability and causing excessive crystallization during sintering. Simultaneously, fluorine is easily volatilized at high temperatures, causing compositional deviation and performance instability, thus affecting fluorescence lifetime. For example, the NaF content is 1 mol%, 1.5 mol%, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 5.5 mol%, 6 mol%, 8 mol%, 10 mol%, or any combination of the above values.

[0036] To further synergistically reduce the sintering temperature, the Na₂O content is 1-10 mol%. If it is less than 1 mol%, its fluxing effect is insufficient, resulting in high glass viscosity, which is not conducive to achieving sufficient densification during sintering at the target temperature. If it is greater than 10 mol%, too many Si-O-Si bonds will be broken, severely damaging the integrity of the glass matrix network, leading to a sharp decline in chemical stability, mechanical strength, and thermal stability, seriously affecting luminescent performance. For example, the Na₂O content is 1 mol%, 1.5 mol%, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 5.5 mol%, 6 mol%, 8 mol%, 10 mol%, or any combination of the above values.

[0037] To jointly suppress crystallization and optimize high-temperature viscosity, the MgO content is 2-12 mol%, and the CaO content is 3-13 mol%. If the content is too low (MgO < 2 mol% or CaO < 3 mol%), the mixed alkaline earth effect cannot be effectively utilized to suppress the crystallization tendency of the glass matrix during heat treatment, and the chemical stability of the glass matrix is ​​also poor. If the content is too high (MgO > 12 mol% or CaO > 13 mol%), the glass network will be excessively broken, reducing its chemical durability and making it difficult to obtain uniform and transparent fluorescent glass. For example, the MgO content is 12 mol%, 3 mol%, 4 mol%, 5 mol%, 5.5 mol%, 6 mol%, 8 mol%, 10 mol%, 12 mol%, or any two of the above values.

[0038] To further optimize performance by utilizing the mixed alkali effect of MgO and CaO, the K2O content is 1-10 mol%. If it is less than 1 mol%, it cannot produce an effective synergistic effect with Na2O, and its additional contribution to inhibiting crystallization and reducing melting temperature is not significant. If it is greater than 10 mol%, excessive K2O will introduce too many network bond breaks due to its large ionic radius. Similar to excessive Na2O, it will severely weaken the glass network structure and adversely affect thermal and chemical stability. For example, the K2O content is 1 mol%, 1.5 mol%, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 5.5 mol%, 6 mol%, 8 mol%, 10 mol%, or any two of the above values.

[0039] In summary, the specific composition system described above can ultimately achieve a lower sintering temperature, avoiding damage to the Ce:YAG phosphor structure, while obtaining good chemical stability and protecting the phosphor interface from corrosion, making it suitable for high-power WLED lighting devices.

[0040] In this invention, it is understood that the Ce:YAG phosphor used is commercially available Y3Al5O. 12 Ce, 450nm excitation, 555nm emission.

[0041] According to some embodiments of the present invention, the phosphor in the fluorescent glass has a mass percentage of 10-60 wt%.

[0042] In this invention, when the mass percentage of phosphor is less than 10 wt%, the phosphor's absorption of blue light is insufficient, leading to a higher color temperature and lower luminous efficiency in the device. When the content continues to increase to above 60 wt%, the excessively dense phosphor particles trigger a significant concentration quenching effect, while simultaneously exacerbating light scattering, which in turn leads to a decrease in internal quantum efficiency and luminous intensity. Exemplarily, in the fluorescent glass, the mass percentage of phosphor is 10 wt%, 15 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, or any two of the above values, preferably 40-50 wt%.

[0043] A second aspect of the present invention provides a method for preparing the fluorescent glass described in the first aspect, comprising: S1. SiO2, Al2O3, NaF, Na2O, MgO, CaO and K2O are mixed evenly and then melted to obtain a molten liquid. After cooling, glass powder is obtained. S2, mix the glass powder and Y3Al5O 12 Ce phosphor is mixed evenly and then sintered to obtain fluorescent glass.

[0044] In this invention, the above preparation method is simple, directly mixing the glass powder obtained in S1 with commercially available Y3Al5O 12 The process involves mixing Ce phosphors and sintering them to form Ce:YAG fluorescent glass. This method is simple, stable, and controllable, and has a low cost, giving it a cost advantage.

[0045] In this invention, it is understood that the amount of the raw materials used is: 45-55 mol% SiO2, 15-25 mol% Al2O3, 1-10 mol% NaF, 1-10 mol% Na2O, 2-12 mol% MgO, 3-13 mol% CaO and 1-10 mol% K2O.

[0046] In this invention, it is understood that the cooling can be performed in water.

[0047] According to some embodiments of the present invention, in step S1, the melting conditions include: a melting temperature of 1200~1400℃ and a melting time of 1~4h.

[0048] In this invention, the melting temperature within the aforementioned range ensures that all oxide raw materials can be completely melted and fully homogenized in the liquid phase, thereby forming a glass melt with uniform chemical composition. The holding time of 1 to 4 hours provides kinetic assurance for this homogenization process, while allowing sufficient time for gases in the melt to escape, significantly reducing internal bubble defects. The resulting glass matrix exhibits excellent optical homogeneity and stable chemical properties.

[0049] According to some embodiments of the present invention, in step S2, the sintering conditions include: heating to 600-650°C at a heating rate of 2-10°C / min, and sintering for 10-50 min.

[0050] In this invention, the aforementioned heating rate allows for the slow decomposition of organic impurities and evaporation of moisture in the glass powder, reducing the risk of sample cracking due to thermal stress. Strictly controlling the sintering temperature within the range of 600-650℃, far below the degradation temperature of Ce:YAG phosphor, and maintaining this temperature for 10-50 minutes, allows the glass powder to reach a viscous flow state, fully encapsulating the phosphor particles and achieving densification. Simultaneously, it maximally suppresses the thermal erosion of the phosphor lattice and interfacial reactions by the glass components, thereby improving internal quantum efficiency.

[0051] According to some embodiments of the present invention, a glass matrix and Y3Al5O are used. 12 Based on the total mass of Ce phosphor, the percentage of phosphor used is 10~60wt%.

[0052] In this invention, when the content is below 10wt%, insufficient blue light absorption leads to excessively high device color temperature and low luminous efficiency; if the content exceeds 60wt%, the phosphor particles are too close together, which will trigger a concentration quenching effect and exacerbate light scattering, thus reducing luminous efficiency. For example, the percentage of phosphor used is 10wt%, 15wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, or any two of the above values, preferably 40-50wt%.

[0053] According to some embodiments of the present invention, in order to facilitate subsequent low-temperature densification sintering, the method further includes: grinding the glass powder after the molten liquid has been cooled to 10-15 micrometers.

[0054] According to some embodiments of the present invention, the method further includes: cutting the obtained Ce:YAG fluorescent glass into thin slices with a thickness of 0.2 mm to 1.25 mm and polishing them.

[0055] In this invention, a diamond wire cutter can be used to cut fluorescent glass.

[0056] In this invention, a fluorescent glass thickness of less than 0.2 mm leads to insufficient blue light absorption and blue light leakage, while a thickness greater than 1.25 mm increases internal light scattering and absorption losses, reducing light extraction efficiency. Polishing significantly reduces Fresnel reflection losses and light scattering caused by roughness when light enters and exits the sample surface.

[0057] After precise thickness control and polishing, the fluorescent glass sheet can achieve higher light extraction efficiency and better heat dissipation performance when encapsulated into WLED devices, thereby ensuring that the final WLED device has a high color rendering index, high luminous efficiency and stable light and color output.

[0058] For example, the thickness of the fluorescent glass is 0.2 mm, 0.25 mm, 0.3 mm, 0.5 mm, 0.75 mm, 0.8 mm, 1 mm and 1.25 mm, or any two of the above values, preferably 0.4 to 0.6 mm.

[0059] A third aspect of the present invention provides a WLED lighting device comprising the fluorescent glass described in the first aspect.

[0060] In this invention, the device further includes a blue LED chip and a heat dissipation substrate. The fluorescent glass is fixed to the heat dissipation substrate by a thermally conductive adhesive layer and is located on the light emission path of the blue LED chip. An optical lens is provided on the side of the fluorescent glass away from the blue LED chip. The optical lens is made of quartz glass or sapphire. A sealed cavity is formed between the optical lens and the fluorescent glass, and the cavity is filled with an inert gas.

[0061] The fourth aspect of the present invention provides an application of the fluorescent glass described in the first aspect in a WLED lighting device.

[0062] In this invention, the fluorescent glass described in the first aspect is applied to WLED lighting devices, which can achieve a color rendering index of 54 to 59 and a luminous efficiency of not less than 119 lm / W (preferably not less than 140 lm / W).

[0063] The WLED lighting device described in this invention can serve as a high-power, high-brightness, and long-life white LED lighting device, such as automotive headlights, special lighting, and high-end general lighting. It can withstand higher operating currents and chip temperatures, exhibiting longer fluorescence decay lifetime and stronger resistance to thermal quenching, thus significantly promoting the development of solid-state lighting technology towards higher performance.

[0064] The advantages of the method of the present invention will be illustrated below through examples.

[0065] In the following examples, the crystal structure of the phosphor was tested using an X'Pert PRO X-ray diffractometer.

[0066] Excitation and emission spectra were measured using an Edinburgh (FL1000) fluorescence spectrometer.

[0067] The internal / external quantum efficiency of luminescence was measured using an Edinburgh (FL1000) fluorescence spectrometer.

[0068] Color rendering index and color temperature were tested using the Far East HAAS-2000.

[0069] Luminous efficiency was tested using the Yuanfang HAAS-2000.

[0070] Fluorescence lifetime was measured using an Edinburgh (FL1000) fluorescence spectrometer.

[0071] Luminous intensity retention rate = luminous intensity measured at 175℃ / luminous intensity measured at room temperature × 100%.

[0072] Example 1 S1. Weigh out 50 mol% SiO2, 20 mol% Al2O3, 5 mol% NaF, 5 mol% Na2O, 7 mol% MgO, 8 mol% CaO, and 5 mol% K2O according to stoichiometric coefficients. Then, place the above raw materials in an agate mortar and grind them thoroughly. Pour the ground mixed powder into an alumina crucible and sinter it in a high-temperature furnace at 1300℃ for 2 hours to obtain a molten liquid. Pour it into water and cool it to obtain a precursor glass block. Finally, grind the glass precursor into 13 micrometer glass powder. S2. The glass powder and Ce:YAG phosphor are mixed evenly to obtain a mixture, wherein the content of Ce:YAG phosphor accounts for 10wt% of the mixture. The mixture is placed in a muffle furnace at 640℃ for sintering. The sintering process is as follows: the initial temperature is room temperature, the temperature is increased to the sintering temperature at a heating rate of 5℃ / min, and then held at this temperature for 30min. Then the temperature is lowered with the furnace and naturally cooled to obtain a large piece of YAG fluorescent glass. The obtained large piece of YAG fluorescent glass is then cut to a thickness of 0.5mm using a diamond wire cutter and polished to obtain the sample YAG fluorescent glass.

[0073] Examples 2-6 The method is the same as in Example 1, except that the content of Ce:YAG phosphor in Examples 2-6 is 20wt%, 30wt%, 40wt%, 50wt%, and 60wt% of the mixture, respectively.

[0074] Example 7 The method is the same as in Example 1, except that the molar fraction of SiO2 is 45 mol.

[0075] Example 8 The method is the same as in Example 1, except that the amount of NaF used is 1 mol.

[0076] Example 9 The method is the same as in Example 1, except that the amount of NaF used is 3 mol.

[0077] Example 10 The method is the same as in Example 1, except that the amount of MgO is 2 mol% and the amount of CaO is 13 mol%.

[0078] Examples 11-12 The method is the same as in Example 4, except that the fluorescent glass is cut into thin slices of 0.2 mm and 1 mm, respectively.

[0079] Comparative Example 1 The method is the same as in Example 1, except that the SiO2 content is 40 mol.

[0080] Comparative Example 2 The method is the same as in Example 1, except that the amount of NaF used is 12 mol.

[0081] Comparative Example 3 The method is the same as in Example 1, except that it does not contain Na2O.

[0082] Comparative Example 4 The method is the same as in Example 1, except that it does not contain MgO and CaO.

[0083] Comparative Example 5 The method is the same as in Example 1, except that the content of Ce:YAG phosphor accounts for 5 wt% of the mixture.

[0084] Test case The internal and external quantum efficiency, thermal quenching performance (luminescence intensity retention rate), and fluorescence lifetime of the fluorescent glasses prepared in the examples and comparative examples were tested, and the results are shown in Table 1.

[0085] Further, the fluorescent glass was fabricated into a WLED lighting device. Specifically, the fluorescent glass obtained in the examples and comparative examples was polished on both sides and then tightly bonded to the light-emitting surface of a 450 nm blue LED chip (InGaN chip) using an inorganic encapsulating agent (silica sol). Subsequently, electrical connections were completed through wire bonding, and the device was assembled into a lamp holder with a high thermal conductivity metal or ceramic substrate. Finally, a standard packaging process was performed to obtain the WLED lighting device. The color temperature, color rendering index, and luminous efficiency of the WLED lighting device were tested under the excitation of a 450 nm blue LED chip, and the results are shown in Table 2.

[0086] Table 1

[0087] Table 2

[0088] Figure 1By comparing with the standard Ce:YAG diffraction peaks, it can be confirmed that in the fluorescent glasses of Examples 1-6, the phosphor maintains a complete crystal structure in the glass matrix without significant phase transition or decomposition, indicating that the low-temperature sintering process effectively protects the phosphor lattice.

[0089] Figure 2 The figure shows the emission spectrum of the fluorescent glass prepared in Example 5 under specific wavelength excitation. As can be seen from the figure, the fluorescent glass can be effectively excited by blue light and emits yellow light, which is consistent with the luminescence characteristics of YAG:Ce and is suitable for blue LED excitation.

[0090] Figure 3 The following are emission spectra of fluorescent glasses with different phosphor doping amounts in Examples 1-6. It can be seen that as the phosphor content increases, the emission intensity of yellow light first increases and then decreases, indicating that the optimal doping range (e.g., 40~50wt%) is optimal. Excessive doping can lead to quenching.

[0091] Figure 4 The transmittance spectra of fluorescent glasses with different phosphor doping amounts in Examples 1-6 show the transmittance curves of fluorescent glasses with different phosphor contents. The higher the phosphor content, the lower the transmittance in the blue light region, indicating that more blue light is absorbed and converted into yellow light. However, too high a content will affect the overall transmittance and uniformity.

[0092] Figure 5 The transmittance spectra of fluorescent glass at different sintering temperatures (Example 5 uses a sintering temperature of 640°C) are shown. The transmittance of fluorescent glass prepared at different sintering temperatures (with constant glass matrix and phosphor doping amounts) was compared. This indicates that sintering temperatures that are too low or too high will affect the density and transmittance of the glass, and 600~650°C is the optimal sintering temperature range.

[0093] Figure 6 The emission spectra of the phosphor and the fluorescent glass in Example 5 at different test temperatures were shown, comparing the luminescence stability of the original phosphor and the fluorescent glass during the heating process. This indicates that the fluorescent glass maintains its luminescence intensity better at high temperatures, demonstrating that the glass matrix protects the phosphor and improves its thermal stability.

[0094] Figure 7 The graphs show a comparison of the EQE and IQE of fluorescent glass and phosphor, comparing the quantum efficiency of the fluorescent glass and the original phosphor. The results indicate that the IQE of the fluorescent glass is higher than that of the phosphor, suggesting that the glass matrix does not significantly impair the luminescence performance of the phosphor, and the higher EQE indicates superior light extraction efficiency.

[0095] Figure 8The graph shows the fluorescence lifetime curves of the fluorescent glass and phosphor in Example 5. It can be seen from the graph that the fluorescent glass in Example 5 has a longer fluorescence lifetime (above 60 ns), indicating that the material has good luminescence stability and a low quenching tendency.

[0096] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A fluorescent glass, characterized in that, The fluorescent glass comprises a glass matrix and Y3Al5O. 12 Ce phosphor; The glass matrix comprises, by molar percentage: 45-55 mol% SiO2, 15-25 mol% Al2O3, 1-10 mol% NaF, 1-10 mol% Na2O, 2-12 mol% MgO, 3-13 mol% CaO, and 1-10 mol% K2O.

2. The fluorescent glass according to claim 1, characterized in that, The glass matrix comprises, by molar percentage: 48-52 mol% SiO2, 18-22 mol% Al2O3, 4-6 mol% NaF, 4-6 mol% Na2O, 6-8 mol% MgO, 7-9 mol% CaO, and 4-6 mol% K2O.

3. The fluorescent glass according to claim 1, characterized in that, In the fluorescent glass, the mass percentage of the phosphor is 10~60wt%.

4. The fluorescent glass according to claim 1, characterized in that, In the fluorescent glass, the mass percentage of the phosphor is 40~50wt%.

5. A method for preparing fluorescent glass according to any one of claims 1-4, characterized in that, include: S1. SiO2, Al2O3, NaF, Na2O, MgO, CaO and K2O are mixed evenly and then melted to obtain a molten liquid. After cooling, glass powder is obtained. S2, mix the glass powder and Y3Al5O 12 Ce phosphor is mixed evenly and then sintered to obtain fluorescent glass.

6. The preparation method according to claim 5, characterized in that, The sintering conditions include: heating to 600-650°C at a heating rate of 2-10°C / min, and sintering for 10-50 min.

7. The preparation method according to claim 5, characterized in that, The method further includes grinding the glass matrix after the molten liquid has cooled to 10-15 micrometers.

8. The preparation method according to any one of claims 5-7, characterized in that, The method further includes: cutting the obtained fluorescent glass into thin slices with a thickness of 0.2 mm to 1.25 mm and polishing them.

9. A WLED lighting device, characterized in that, Includes the fluorescent glass according to any one of claims 1-4.

10. The application of the fluorescent glass according to any one of claims 1-4 or the fluorescent glass prepared by the preparation method according to any one of claims 4-9 in WLED lighting devices.

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