A rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white light LED and its preparation method

Abstract

This invention relates to a rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs and its preparation method. The main crystalline phase of the microcrystalline glass is MgAl2Si3O. 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+ Under ultraviolet light irradiation, rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light with a color temperature of 3335–4500 K and a color rendering index (CRI) of not less than 82.7. The preparation method involves preparing a base glass from SiO2, Al2O3, MgO, ZnO, CeO2, Tb4O7, and Sm2O3, followed by controlled nucleation and crystallization treatment to obtain the microcrystalline glass. The product of this invention exhibits uniform distribution, good transparency, and excellent thermal and physicochemical stability, making it suitable for constructing high CRI, low color temperature white LED devices excited by ultraviolet chips. The preparation method of this invention is simple, low-cost, and has industrialization potential.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, and relates to a rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs and its preparation method. Background Technology

[0002] White light-emitting diodes (WLEDs), as a new generation of solid-state lighting sources, have advantages such as high efficiency, long lifespan, fast response speed, and environmental friendliness. They are widely used in automotive headlights, LCD backlights, streetlights, and general lighting.

[0003] To date, commercially available WLEDs are primarily achieved through combinations of blue or ultraviolet LED chips and multi-color phosphors, with significant efforts focused on researching different phosphors. The most typical example is the use of blue InGaN chips to excite yellow yttrium aluminum garnet (Y3Al5O3). 12 YAG:Ce phosphors dominate the WLED lighting market due to their high lumen efficiency and low production cost. However, this method requires dispersing the phosphor in an organic binder. The heat generated by the chip in high-power devices causes the organic encapsulation material, with its poor thermal stability and low thermal conductivity, to age and yellow, leading to reduced luminous efficiency, color coordinate drift, and other problems, thus decreasing the long-term reliability and lifespan of the device. Furthermore, the refractive index of YAG:Ce particles (1.84) is mismatched with that of epoxy resin or silicone (1.55), resulting in poor transparency after homogenization and significant light scattering loss. Therefore, there is an urgent need to develop novel inorganic transparent solid-state luminescent materials with high thermal conductivity and good chemical stability.

[0004] Luminescent glass-ceramic combines the advantages of crystalline and glass materials, possessing not only excellent transparency and high mechanical properties, but also good thermal stability, durability, and lifespan. Furthermore, compared to luminescent ceramics and single-crystal materials, fluorescent glass-ceramic offers a wider variety of types, more flexible design, and can be shaped and processed using various glass fabrication techniques. It is also inexpensive, simple to prepare, and easy to mass-produce, making it a promising alternative to phosphors for WLEDs. For example, reference 1 (YAGglass-ceramic phosphor for white LED(I):background and development[P].Proc.SPIE,2005.5941:594111.) first prepared YAG:Ce fluorescent glass-ceramic suitable for blue light excitation, enabling resin-free encapsulation and exhibiting high thermal stability and luminous efficiency, making it a mainstream phosphor conversion material for next-generation WLEDs. However, the emission spectrum of YAG:Ce fluorescent microcrystalline glass excited by blue light chips is mainly yellow light, with insufficient emission of cyan, green and red light. This results in WLED devices exhibiting a low color rendering index and a high correlated color temperature, and poor white light quality, which is not conducive to indoor lighting and applications with high color requirements.

[0005] High color temperatures can lead to eye fatigue, macular degeneration, retinal damage, insomnia, and other health problems. Low color rendering index (CRI) can impair the eye's color perception. Prolonged exposure to light sources with poor color rendering can reduce the sensitivity of the cone cells in the eye, easily causing visual fatigue and potentially leading to myopia. In the existing technology, those skilled in the art have long sought to solve the problem of low CRI and high correlated color temperature in order to produce microcrystalline glass that combines both. However, none of these efforts have been successful.

[0006] For example:

[0007] Document 2 (Synthesis and luminescence properties of Ce:Y3Al5O 12 glassceramic by spontaneous crystallization[J].Materials Letters, 2015,151:31-34.) Using Ce 3+ A method for spontaneous crystallization of PbO-SiO2-Al2O3-Y2O3-B2O3 glass during melting and quenching was used to successfully prepare transparent YAG:Ce microcrystalline glass. In this method, the sample emitted white light under 465nm blue light excitation. The color temperature of the assembled WLED was 5561K, which is high. The color rendering index was 69.3, which is low. The transparency of the sample was poor, and the composition contained lead.

[0008] Document 3 (Erosion behavior and luminescence properties of Y3Al5O 12 :Ce 3+ -embedded calcium bismuth borate glass-ceramics for WLEDs[J].Journal of the American Ceramic Society,2019,102(4):2053-2065.) The pulverized B2O3-Bi2O3-CaO-Eu2O3 base glass was mixed with commercial YAG:Ce phosphor and eutectic at 640-700℃ to obtain YAG:Ce microcrystalline glass. The optimal color temperature of this YAG-microcrystalline glass and the WLED packaged with blue chip is 3940K, and the color rendering index is 70.1. In this technical solution, although the resulting material has a low color temperature, its color rendering index is also low. In addition, the material has low visible light transmittance and poor transparency (the poor transparency is partly due to the mismatch in refractive indices between the glass matrix and the phosphor, and partly because this literature uses a sintering method. During the sintering process, the raw material particles or powder usually begin to melt or partially melt first, and then gradually bond together. In this process, the gaps between the particles may form pores. Defects such as pores generated during sintering will also reduce the transmittance of visible light due to the absorption and scattering of light. Furthermore, when the phosphor and glass are remelted, the molten glass will erode the phosphor particles (erosion occurs because the sintering temperature is high, and a reaction occurs between the main glass and the YAG:Ce particles, leading to the corrosion of the phosphor particles), causing defects in the microcrystalline glass, resulting in a decrease in the luminescent and mechanical properties of the material.

[0009] Reference 4 (Rare Earth Ions (Ce) 3+ / Tb 3+ / Sm 3+ Study on the optical properties of yttrium phosphate-doped glass crystals [D]. Ningbo University, 2018. Ce was prepared. 3+ / Tb 3+ Transparent glass-ceramics co-doped with YPO4 nanocrystals, the glass matrix composition being 45SiO2-19Al2O3-21Na2CO3-10YF3-5P2O5, Tb 3+ The content is 1 mol%, Ce 3+The content ranges from 0 to 1.5 mol%. In this scheme, the sample emits white light under 331 nm excitation, with a color rendering index (CRI) of 58.4–86.3 and a color temperature of 5304–5930 K, which is high. Furthermore, this glass system contains fluorides, which are harmful to humans and the environment. The physicochemical and thermal stability of phosphate-based microcrystalline glass is also poor. The luminescent performance of rare-earth doped glass may be affected by ambient temperature and humidity, leading to changes in the LED's color temperature and CRI, thus impacting the color quality of lighting and displays.

[0010] Reference 5 (Study on rare earth-doped white light-emitting transparent microcrystalline glass [D]. China Jiliang University, 2014.) prepared Ce 3+ / Tb 3+ BaYF5-doped glass-ceramics were used to obtain glass-ceramics. While the resulting glass-ceramics possess advantages such as low phonon energy, high luminous efficiency, and resistance to rare-earth ion concentration quenching, and their emission spectrum has chromaticity coordinates (0.287, 0.336) primarily within the white light region, their color temperature is high at 8000K, and their color rendering index is only 65. Furthermore, these glass-ceramics contain fluorides, which are harmful to human health and the environment.

[0011] Reference 6 (Study on the luminescent properties of rare earth-doped LiYF4 microcrystalline glass for LEDs [D]. Ningbo University, 2019) prepared Pr using a melt method. 3+ While ion-doped transparent glass-ceramics containing LiYF4 nanocrystals offer advantages such as low phonon energy, high luminous efficiency, and resistance to rare-earth ion concentration quenching, and emit white light when excited at the optimal wavelength of 444 nm, the color temperature of the WLED encapsulated in this glass-ceramic is 5791 K, and the color rendering index is 60.8. Furthermore, this glass-ceramic contains fluorides, which are harmful to human health and the environment.

[0012] In summary, although researchers have conducted many studies on rare earth ion-doped transparent microcrystalline glasses, the problems of high color temperature and low color rendering index still exist.

[0013] Therefore, it is of great significance to study a rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs and its preparation method to solve the above problems. Summary of the Invention

[0014] The purpose of this invention is to solve the problems existing in the prior art and to provide a rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs and its preparation method.

[0015] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0016] A rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs, with MgAl2Si3O as the main crystalline phase. 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+ ;

[0017] Rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs is prepared by controlled nucleation and crystallization of a base glass. The base glass has the following composition: SiO2 57.51–57.64 mol%, Al2O3 20.82–20.87 mol%, MgO 14.86–14.91 mol%, ZnO 5.95–5.96 mol%, CeO2 0.02–0.06 mol%, Tb4O7 0.10–0.30 mol%, and Sm2O3 0.40–0.50 mol%.

[0018] Under ultraviolet light irradiation, the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light (under ultraviolet light irradiation, the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass can simultaneously emit blue light, green light, and red light, and these multi-color lights are mixed together to achieve white light emission); the white light-emitting diode (WLED) assembled from the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and the ultraviolet LED chip has a color temperature of 3335-4500K and a color rendering index of not less than 82.7.

[0019] As a preferred technical solution:

[0020] The rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs, as described above, has a Vickers hardness of not less than 8 GPa and a visible light transmittance of not less than 80%.

[0021] The method for preparing rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs as described above is characterized by: mixing SiO2, Al2O3, MgO, ZnO, CeO2, Tb4O7 and Sm2O3 into a mixture, melting the mixture to form a glass melt, casting it into a mold, and then annealing it to obtain a base glass. The base glass is then subjected to controlled nucleation and crystallization treatment to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs.

[0022] The preparation method of rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, as described above, includes the following specific steps:

[0023] (1) Weigh the glass batch materials SiO2, Al2O3, MgO, ZnO, CeO2, Tb4O7 and Sm2O3 precisely according to the set molar percentage, and grind them in an agate mortar until they are evenly mixed to obtain a mixture;

[0024] (2) The mixture is loaded into a corundum crucible and placed in a high-temperature electric furnace. The temperature is raised to 1600-1640℃ under a reducing atmosphere and heated for 4-6 hours to obtain a uniform glass melt.

[0025] (3) Pour the glass melt into a preheated graphite mold for molding, and anneal the molded glass at 680-750°C for 3-6 hours. After cooling to room temperature, the base glass is obtained.

[0026] (4) The base glass is placed in a high-temperature electric furnace and heated from room temperature to 790-850°C at a heating rate of 3-10°C / min under a reducing atmosphere. The temperature is held for 3-8 hours for nucleation heat treatment. Then, the temperature is further increased to 900-1000°C at a heating rate of 3-10°C / min and held for 0.5-1.5 hours for crystallization heat treatment. Finally, the glass is cooled to room temperature with the furnace to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass.

[0027] In the above-described method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, the reducing atmosphere in steps (2) and (4) is CO.

[0028] In the above-described method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, the preheating temperature in step (3) is 300-600℃.

[0029] Invention Mechanism:

[0030] This invention utilizes a melting method to melt Ce 3+ 、Tb 3+ 、Sm 3+ Rare earth ions are co-doped into the base glass of the MAS system, and the metastable phase MgAl2Si3O is precipitated through further heat treatment. 10 In MgAl2Si3O 10 Establishing Ce in the crystal phase 3+ -Tb 3+ -Sm 3+ Energy transfer produces white light emission. Under ultraviolet light excitation, Ce... 3+ Emitting blue-violet light at 350–400 nm, Tb 3+ Emits blue and green light in the 400–560 nm range, Sm 3+ Emits red light in the 560–670 nm range. By controlling the ratio of the three components, the type, size, and distribution of precipitated grains can be adjusted to prepare MgAl2Si3O4. 10A transparent microcrystalline glass with MgAl₂Si₃O₃ as the main crystalline phase. 10 The crystalline phase possesses the high mechanical properties of crystals, and its refractive index is similar to that of the MAS glass matrix, thus ensuring high transparency. Furthermore, by rationally controlling the proportions of the three rare-earth ions, the relative intensities of the blue, green, and red emission bands can be tuned to obtain the low color temperature white light of this invention.

[0031] Compared with existing technologies, the rare earth ion-doped magnesium aluminum silicon microcrystalline glass of the present invention has a simple preparation method, widely available raw materials, low cost, less pollution during production, and is environmentally friendly. The prepared material is physically and chemically stable, has good luminescence performance, and controllable color temperature, making it an ideal candidate material for white light WLED and related display and lighting devices.

[0032] Furthermore, compared to similar luminescent glasses, it possesses more stable physicochemical properties (Vickers hardness above 8 GPa), making it easier to adjust for high luminous efficiency and low color temperature (3335–4500 K) in WLEDs. Specifically, the precipitated MgAl2Si3O 10 Compared to glass substrates, crystals have lower phonon energies, which helps reduce the nonradiative energy loss of rare-earth ion excited states and prolong the excited state lifetime, thus enhancing the luminescence intensity of rare-earth ions; MgAl2Si3O in microcrystalline glass 10 The crystals are discretely distributed, providing more dispersed sites to accommodate rare earth ions compared to a glass matrix. The doping concentration of rare earth ions in MgAl₂Si₃O₃ can be precisely controlled by adjusting the heat treatment process of the glass-ceramic and the doping concentration of rare earth ions. 10 The size, content, and distribution of crystals make it easier to adjust the spectral distribution of light emission (i.e., it is easier to change the ratio of blue, green, and red spectra), thereby changing the color temperature of the light emission.

[0033] Patent CN 104389018 A discloses the doping of Tb in α-NaYF4 single crystals. 3+ / Sm 3+ / Ce 3+ First, it is an α-NaYF4 single crystal, unlike the MgAl2Si3O4 used in this invention. 10 In glass-ceramics with the main crystalline phase, the emission spectra of luminescent ions differ between the two matrix materials. For example, in the emission spectrum of α-NaYF4 single crystal, a significant Tb level appears. 3+ 4G 5 / 2 →6H 7 / 2 (585nm) and 4G 5 / 2 →6H 7 / 2 (585nm) transition, Sm 3+ At 600nm (4G) 5 / 2 →6H 7 / 2The emitted light at point () is weaker; while in the microcrystalline glass of this invention, Sm 3+ 4G at 600nm 5 / 2 →6H 7 / 2 The transition is more advantageous. Therefore, compared to other materials, the microcrystalline glass of this invention can achieve more red light emission, which is beneficial for obtaining a lower color temperature. Secondly, in patent CN 104389018A, Tb 3+ 、Sm 3+ Ce 3+ The total amount of ions is 0.0624 mol% < x + y + z < 0.0896 mol%. The rare earth ion content is relatively low. Although white light was obtained, the proportion of red light is still insufficient, resulting in a relatively high color temperature. Furthermore, with the increase of Tb... 3+ 、Sm 3+ Ce 3+ The total ion content changes, and the color temperature changes irregularly. However, this invention is based on MgAl2Si3O... 10 The microcrystalline glass matrix with Tb as the main crystalline phase was determined through extensive experimental exploration. 3+ 、Sm 3+ Ce 3+ Within the specific range of ion doping content in this invention (0.02–0.06 mol% CeO2, 0.10–0.30 mol% Tb4O7, 0.49–0.50 mol% Sm2O3), the emission of white light with a low color temperature and high color rendering index can be achieved, with a color temperature of 3479–4500 K and a color rendering index of not less than 82.7. If the total content of CeO2 and Tb4O7 doping is too high, it will lead to a colder color temperature (>4500 K). The color rendering index is related to the spectral distribution, which is the result of the synergistic effect of various factors such as matrix material and rare earth ion content. The closer it is to the natural spectrum (or standard spectrum), the higher the color rendering index. To improve the color rendering index, the missing spectrum needs to be added. This invention introduces a certain amount of Sm2O3 to supplement the red spectrum and adjusts the ratio of blue, green, and red spectra by changing the content of CeO2 and Tb4O7, thereby obtaining a high color rendering index.

[0034] Beneficial effects:

[0035] (1) The present invention discloses a method for preparing rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, which for the first time utilizes cerium, terbium, and samarium co-doped metastable phase MgAl2Si3O 10 White light-emitting diodes are fabricated by combining microcrystalline glass with ultraviolet chips to achieve white light emission; rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass can simultaneously emit blue, green and red light under ultraviolet light excitation and directly mix them to form white light, without the need for color matching through multiple fluorescent materials, which can effectively improve the color rendering index and color temperature control of white LEDs.

[0036] (2) The rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass of the present invention has uniform crystal distribution, good transparency, and good thermal and physicochemical stability, and can be used to construct white LED devices with high color rendering index and low color temperature excited by ultraviolet chips.

[0037] (3) The rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LED of the present invention is beneficial to simplifying the packaging structure of white LED, with simple preparation process, low cost, and industrialization potential (such as good stability, long service life, and convenient processing). Attached Figure Description

[0038] Figure 1 This is the excitation spectrum of the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass prepared in Example 1 at a monitoring wavelength of 420 nm.

[0039] Figure 2 This is the X-ray diffraction pattern of the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass prepared in Example 2;

[0040] Figure 3 These are the emission spectra of rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass prepared in Examples 1-4 under 365nm ultraviolet light excitation;

[0041] Figure 4 The image shows the CIE color coordinate diagrams of the WLEDs assembled with rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and 365nm ultraviolet chips prepared in Examples 1-4. Detailed Implementation

[0042] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0043] The testing standards / methods involved in this invention are as follows:

[0044] Color temperature and color rendering index: A WLED device was obtained by assembling a 1.2mm thick rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass sample with a 365nm ultraviolet LED chip. The color temperature and color rendering index of the WLED were tested using an HSP-3000 spectrometer from Hangzhou Hongpu Optoelectronics Co., Ltd.

[0045] Vickers hardness: After grinding and polishing, the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass sample was tested for Vickers hardness using an FV-700 microhardness tester. The load applied to the surface of the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass sample was 29.4 N, and the holding time was 10 s.

[0046] Visible light transmittance: The rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass sample was processed into a 2 mm thick sheet. After polishing both sides, the average light transmittance in the wavelength range of 380-780 nm was measured using a Hitachi U-3310 UV-Vis spectrophotometer.

[0047] Example 1

[0048] A method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, the specific steps of which are as follows:

[0049] (1) Weigh the glass batch material precisely according to the set molar percentages, namely SiO2 57.52mol%, Al2O3 20.83mol%, MgO 14.88mol%, ZnO 5.95mol%, CeO2 0.02mol%, Tb4O7 0.30mol%, and Sm2O3 0.50mol%, and grind it in an agate mortar until it is evenly mixed to obtain a mixture.

[0050] (2) The mixture is loaded into a corundum crucible and placed in a high-temperature electric furnace. The temperature is raised to 1630°C under a CO atmosphere and heated for 4 hours to obtain a uniform glass melt.

[0051] (3) Pour the glass melt into a graphite mold preheated at 500°C for molding, and anneal the molded glass at 680°C for 4 hours. After cooling to room temperature, the base glass is obtained.

[0052] (4) The base glass is placed in a high-temperature electric furnace and heated from room temperature to 840°C at a heating rate of 5°C / min under CO atmosphere. It is kept at the temperature for 5 hours for nucleation heat treatment. Then, it is heated to 950°C at a heating rate of 5°C / min and kept at the temperature for 1 hour for crystallization heat treatment. Finally, it is cooled to room temperature with the furnace to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass.

[0053] The main crystalline phase of the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is MgAl2Si3O. 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+ ;like Figure 1 As shown, the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass has an excitation spectrum that covers the emission of ultraviolet chips, and can be effectively excited by ultraviolet LED chips; such as Figures 3-4As shown, under ultraviolet light irradiation at a wavelength of 365nm, the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light; the chromaticity coordinates of the WLED assembled with the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and the 365nm ultraviolet chip are (0.3831, 0.4128), the color temperature is 4148K, and the color rendering index is 82.7; the Vickers hardness of the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is 8.29GPa, and the visible light transmittance is 83.82%.

[0054] Example 2

[0055] A method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, the specific steps of which are as follows:

[0056] (1) Weigh the glass batch material precisely according to the set molar percentages, namely SiO2 57.51mol%, Al2O3 20.82mol%, MgO 14.86mol%, ZnO 5.95mol%, CeO2 0.06mol%, Tb4O7 0.30mol%, and Sm2O3 0.50mol%, and grind it in an agate mortar until it is evenly mixed to obtain the mixture.

[0057] (2) The mixture is loaded into a corundum crucible and placed in a high-temperature electric furnace. The temperature is raised to 1620°C under a CO atmosphere and heated for 5 hours to obtain a uniform glass melt.

[0058] (3) Pour the glass melt into a graphite mold preheated at 400°C for molding, and anneal the molded glass at 680°C for 6 hours. After cooling to room temperature, the base glass is obtained.

[0059] (4) The base glass is placed in a high-temperature electric furnace and heated from room temperature to 840°C at a heating rate of 5°C / min under CO atmosphere. It is kept at the temperature for 5 hours for nucleation heat treatment. Then, it is heated to 950°C at a heating rate of 5°C / min and kept at the temperature for 1 hour for crystallization heat treatment. Finally, it is cooled to room temperature with the furnace to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass.

[0060] like Figure 2 As shown, the main crystalline phase of the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is MgAl2Si3O. 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+ ;like Figures 3-4As shown, under ultraviolet light irradiation at a wavelength of 365nm, the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light; the chromaticity coordinates of the WLED assembled with the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and the 365nm ultraviolet chip are (0.3667, 0.3984), the color temperature is 4498K, and the color rendering index is 83.9; the Vickers hardness of the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is 8.27GPa, and the visible light transmittance is 82.31%.

[0061] Example 3

[0062] A method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, the specific steps of which are as follows:

[0063] (1) Weigh the glass batch material precisely according to the set molar percentages, namely SiO2 57.58mol%, Al2O3 20.85mol%, MgO 14.89mol%, ZnO 5.96mol%, CeO2 0.02mol%, Tb4O7 0.20mol%, and Sm2O3 0.50mol%, and grind it in an agate mortar until it is evenly mixed to obtain the mixture.

[0064] (2) The mixture is loaded into a corundum crucible and placed in a high-temperature electric furnace. The temperature is raised to 1600°C under a CO atmosphere and heated for 6 hours to obtain a uniform glass melt.

[0065] (3) Pour the glass melt into a graphite mold preheated at 300°C for molding, and anneal the molded glass at 720°C for 3 hours. After cooling to room temperature, the base glass is obtained.

[0066] (4) The base glass is placed in a high-temperature electric furnace and heated from room temperature to 840°C at a heating rate of 5°C / min under CO atmosphere. It is kept at the temperature for 5 hours for nucleation heat treatment. Then, it is heated to 950°C at a heating rate of 5°C / min and kept at the temperature for 1 hour for crystallization heat treatment. Finally, it is cooled to room temperature with the furnace to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass.

[0067] The main crystalline phase of the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is MgAl2Si3O. 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+ ;like Figures 3-4As shown, under ultraviolet light irradiation at a wavelength of 365nm, the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light; the chromaticity coordinates of the WLED assembled with the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and the 365nm ultraviolet chip are (0.3772, 0.3697), the color temperature is 4016K, and the color rendering index is 88.3; the Vickers hardness of the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is 8.3GPa, and the visible light transmittance is 85.32%.

[0068] Example 4

[0069] A method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, the specific steps of which are as follows:

[0070] (1) Weigh the glass batch material precisely according to the set molar percentages, namely SiO2 57.64mol%, Al2O3 20.87mol%, MgO 14.91mol%, ZnO 5.96mol%, CeO2 0.02mol%, Tb4O7 0.10mol%, and Sm2O3 0.50mol%, and grind it in an agate mortar until it is evenly mixed to obtain a mixture.

[0071] (2) The mixture is loaded into a corundum crucible and placed in a high-temperature electric furnace. The temperature is raised to 1640°C under a CO atmosphere and heated for 4 hours to obtain a uniform glass melt.

[0072] (3) Pour the glass melt into a graphite mold preheated at 600°C for molding, and anneal the molded glass at 750°C for 3 hours. After cooling to room temperature, the base glass is obtained.

[0073] (4) The base glass is placed in a high-temperature electric furnace and heated from room temperature to 840°C at a heating rate of 5°C / min under CO atmosphere. It is kept at the temperature for 5 hours for nucleation heat treatment. Then, it is heated to 950°C at a heating rate of 5°C / min and kept at the temperature for 1 hour for crystallization heat treatment. Finally, it is cooled to room temperature with the furnace to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass.

[0074] The main crystalline phase of the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is MgAl2Si3O. 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+ ;like Figures 3-4As shown, under ultraviolet light irradiation at a wavelength of 365nm, the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light. The chromaticity coordinates of the WLED assembled with the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and the 365nm ultraviolet chip are (0.3826, 0.3208), the color temperature is 3335K, and the color rendering index is 87.1. The Vickers hardness of the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is 8.11GPa, and the visible light transmittance is 86.56%.

[0075] Example 5

[0076] A method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, the specific steps of which are as follows:

[0077] (1) Weigh the glass batch material precisely according to the set molar percentages, namely SiO2 57.56mol%, Al2O3 20.84mol%, MgO 14.89mol%, ZnO 5.95mol%, CeO2 0.06mol%, Tb4O7 0.30mol%, and Sm2O3 0.40mol%, and grind it in an agate mortar until it is evenly mixed to obtain the mixture.

[0078] (2) The mixture is loaded into a corundum crucible and placed in a high-temperature electric furnace. The temperature is raised to 1620°C under a CO atmosphere and heated for 5 hours to obtain a uniform glass melt.

[0079] (3) Pour the glass melt into a graphite mold preheated at 400°C for molding, and anneal the molded glass at 680°C for 6 hours. After cooling to room temperature, the base glass is obtained.

[0080] (4) The base glass is placed in a high-temperature electric furnace and heated from room temperature to 790°C at a heating rate of 3°C / min under CO atmosphere. It is kept at the temperature for 8 hours for nucleation heat treatment. Then, it is heated to 1000°C at a heating rate of 10°C / min and kept at the temperature for 0.5 hours for crystallization heat treatment. Finally, it is cooled to room temperature with the furnace to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass.

[0081] The main crystalline phase of the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is MgAl2Si3O. 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+Under 365nm ultraviolet light irradiation, rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light; the chromaticity coordinates of the WLED assembled with the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and the 365nm ultraviolet chip are (0.3625, 0.3519), the color temperature is 4358K, and the color rendering index is 85.9; the Vickers hardness of the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is 8.13GPa, and the visible light transmittance is 81.92%.

[0082] Example 6

[0083] A method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, the specific steps of which are as follows:

[0084] (1) Weigh the glass batch material precisely according to the set molar percentages, namely SiO2 57.51mol%, Al2O3 20.82mol%, MgO 14.86mol%, ZnO 5.95mol%, CeO2 0.06mol%, Tb4O7 0.30mol%, and Sm2O3 0.50mol%, and grind it in an agate mortar until it is evenly mixed to obtain the mixture.

[0085] (2) The mixture is loaded into a corundum crucible and placed in a high-temperature electric furnace. The temperature is raised to 1620°C under a CO atmosphere and heated for 5 hours to obtain a uniform glass melt.

[0086] (3) Pour the glass melt into a graphite mold preheated at 400°C for molding, and anneal the molded glass at 680°C for 6 hours. After cooling to room temperature, the base glass is obtained.

[0087] (4) The base glass is placed in a high-temperature electric furnace and heated from room temperature to 850°C at a heating rate of 10°C / min under CO atmosphere. The temperature is held for 3 hours for nucleation heat treatment. Then, the temperature is further increased to 1000°C at a heating rate of 3°C / min and held for 0.5 hours for crystallization heat treatment. Finally, the glass is cooled to room temperature with the furnace to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass.

[0088] The main crystalline phase of the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is MgAl2Si3O. 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+Under 365nm ultraviolet light irradiation, rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light; the chromaticity coordinates of the WLED assembled with the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and the 365nm ultraviolet chip are (0.3732, 0.3813), the color temperature is 4215K, and the color rendering index is 86.5; the Vickers hardness of the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is 8.34GPa, and the visible light transmittance is 80.75%.

[0089] Example 7

[0090] A method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, the specific steps of which are as follows:

[0091] (1) Weigh the glass batch material precisely according to the set molar percentages, namely SiO2 57.51mol%, Al2O3 20.82mol%, MgO 14.86mol%, ZnO 5.95mol%, CeO2 0.06mol%, Tb4O7 0.30mol%, and Sm2O3 0.50mol%, and grind it in an agate mortar until it is evenly mixed to obtain the mixture.

[0092] (2) The mixture is loaded into a corundum crucible and placed in a high-temperature electric furnace. The temperature is raised to 1620°C under a CO atmosphere and heated for 5 hours to obtain a uniform glass melt.

[0093] (3) Pour the glass melt into a graphite mold preheated at 400°C for molding, and anneal the molded glass at 680°C for 6 hours. After cooling to room temperature, the base glass is obtained.

[0094] (4) The base glass is placed in a high-temperature electric furnace and heated from room temperature to 790°C at a heating rate of 8°C / min under CO atmosphere. It is kept at the temperature for 8 hours for nucleation heat treatment. Then, it is heated to 900°C at a heating rate of 5°C / min and kept at the temperature for 1.5 hours for crystallization heat treatment. Finally, it is cooled to room temperature with the furnace to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass.

[0095] The main crystalline phase of the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is MgAl2Si3O. 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+Under 365nm ultraviolet light irradiation, rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light; the chromaticity coordinates of the WLED assembled with the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and the 365nm ultraviolet chip are (0.3605, 0.3323), the color temperature is 4272K, and the color rendering index is 84.1; the Vickers hardness of the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is 8.27GPa, and the visible light transmittance is 85.53%.

[0096] Example 8

[0097] A method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs, the specific steps of which are as follows:

[0098] (1) Weigh the glass batch material precisely according to the set molar percentages, namely SiO2 57.64mol%, Al2O3 20.87mol%, MgO 14.91mol%, ZnO 5.96mol%, CeO2 0.02mol%, Tb4O7 0.10mol%, and Sm2O3 0.50mol%, and grind it in an agate mortar until it is evenly mixed to obtain a mixture.

[0099] (2) The mixture is loaded into a corundum crucible and placed in a high-temperature electric furnace. The temperature is raised to 1640°C under a CO atmosphere and heated for 4 hours to obtain a uniform glass melt.

[0100] (3) Pour the glass melt into a graphite mold preheated at 600°C for molding, and anneal the molded glass at 750°C for 3 hours. After cooling to room temperature, the base glass is obtained.

[0101] (4) The base glass is placed in a high-temperature electric furnace and heated from room temperature to 850°C at a heating rate of 5°C / min under CO atmosphere. The temperature is held for 5 hours for nucleation heat treatment. Then, the temperature is further increased to 1000°C at a heating rate of 8°C / min and held for 1 hour for crystallization heat treatment. Finally, the glass is cooled to room temperature with the furnace to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass.

[0102] The main crystalline phase of the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is MgAl2Si3O. 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+Under 365nm ultraviolet light irradiation, rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light; the chromaticity coordinates of the WLED assembled with the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and the 365nm ultraviolet chip are (0.3856, 0.3571), the color temperature is 3651K, and the color rendering index is 90.6; the Vickers hardness of the rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass is 8.24GPa, and the visible light transmittance is 80.43%.

Claims

1. A rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs, characterized in that: The main crystalline phase is MgAl2Si3O 10 The luminescent center is a doped rare-earth ion Ce. 3+ 、Tb 3+ and Sm 3+ ; Rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs is prepared by controlled nucleation and crystallization of a base glass. The base glass has the following composition: SiO2 57.51–57.64 mol%, Al2O3 20.82–20.87 mol%, MgO 14.86–14.91 mol%, ZnO 5.95–5.96 mol%, CeO2 0.02–0.06 mol%, Tb4O7 0.10–0.30 mol%, and Sm2O3 0.40–0.50 mol%. The rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs is produced by mixing SiO2, Al2O3, MgO, ZnO, CeO2, Tb4O7, and Sm2O3 into a mixture, melting the mixture to form a glass melt, casting it into a mold, and then annealing it to obtain a base glass. The base glass is then subjected to controlled nucleation and crystallization treatments. The melting of the mixture to form the glass melt and the controlled nucleation and crystallization treatments of the base glass are both carried out under a reducing atmosphere. Under ultraviolet light irradiation, the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass emits white light; the white light-emitting diode assembled from the rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass and the ultraviolet LED chip has a color temperature of 3335-4500K and a color rendering index of not less than 82.

7.

2. The rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs according to claim 1, characterized in that, The rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass has a Vickers hardness of not less than 8 GPa and a visible light transmittance of not less than 80%.

3. A method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs as described in claim 1 or 2, characterized in that: SiO2, Al2O3, MgO, ZnO, CeO2, Tb4O7 and Sm2O3 are mixed into a mixture, which is then melted to form a glass melt, cast into shape, and annealed to obtain a base glass. The base glass is then subjected to controlled nucleation and crystallization treatment to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet conversion white LEDs.

4. The method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs according to claim 3, characterized in that, The specific steps are as follows: (1) Weigh the glass batch materials SiO2, Al2O3, MgO, ZnO, CeO2, Tb4O7 and Sm2O3 precisely according to the set molar percentage, and grind them in an agate mortar until they are evenly mixed to obtain a mixture; (2) The mixture is loaded into a crucible and placed in a high-temperature electric furnace. The temperature is raised to 1600-1640°C under a reducing atmosphere and heated for 4-6 hours to obtain a uniform glass melt. (3) Pour the glass melt into a preheated graphite mold for molding, and anneal the molded glass at 680-750°C for 3-6 hours. After cooling to room temperature, the base glass is obtained. (4) The base glass is placed in a high-temperature electric furnace and heated from room temperature to 790-850°C at a heating rate of 3-10°C / min under a reducing atmosphere. The temperature is held for 3-8 hours for nucleation heat treatment. Then, the temperature is further increased to 900-1000°C at a heating rate of 3-10°C / min and held for 0.5-1.5 hours for crystallization heat treatment. Finally, the glass is cooled to room temperature with the furnace to obtain rare earth ion-doped magnesium aluminum silicon transparent microcrystalline glass.

5. The method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs according to claim 4, characterized in that, The reducing atmosphere in steps (2) and (4) is CO.

6. The method for preparing rare-earth ion-doped magnesium aluminum silicon transparent microcrystalline glass for ultraviolet-converting white LEDs according to claim 4, characterized in that, The preheating temperature in step (3) is 300-600℃.

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