Fluorophoric glass material for high-power LED and preparation method and application thereof

Abstract

This invention discloses a fluorescent glass material for high-power LEDs, its preparation method, and its application, relating to the field of inorganic glass luminescent materials. The technical solution of this invention includes the following components: glass powder and phosphor, wherein the glass powder is composed of SiO2, B2O3, Al2O3, CaO, Y2O3, and Na2O, and the phosphor is Y3Al5O3. 12 :Ce 3+ Y3Al5O 12 :Ce 3+ Phosphors are mixed with low-melting-point glass powder SiO2-B2O3-Al2O3-CaO-Y2O3-Na2O, pressed into a compact, sintered, and then cut, ground, and polished to obtain a yellow fluorescent conversion material. By optimizing the phosphor concentration and the thickness of the fluorescent glass, the color temperature, color rendering index, and color coordinates of the white light spectrum can be easily controlled, with a maximum luminous efficiency of ~140 lm / W, which can be used in high-power LED white light lighting and display fields.

Description

Technical Field

[0001] This invention relates to a fluorescent glass material for high-power LEDs, its preparation method, and its application, belonging to the field of inorganic light-emitting materials technology. Background Technology

[0002] White LEDs, as the fourth generation of lighting sources, possess numerous advantages such as high efficiency, good stability, long lifespan, and small size, and are widely used in indoor and outdoor lighting. To further expand into special lighting and display fields such as searchlights, projection displays, and automotive headlights, high-power white LEDs have experienced rapid development. Among these advancements, highly efficient and stable all-inorganic phosphor conversion materials are key to the development of high-power LEDs. Phosphor / glass composite materials are well-suited to the new and demanding remote packaging strategies for devices under high-power conditions, effectively addressing reliability and lifespan issues caused by traditional epoxy resin bonding packaging under high-power conditions, such as localized temperature rise, aging, and damp heat degradation. Furthermore, the combination of phosphor / glass composite materials offers diverse options. By adjusting and optimizing the glass composition and mixing, curing, and sintering it with specific phosphors, fluorescent glass materials that combine the high quantum efficiency of phosphors with the high physicochemical stability of the glass matrix can be obtained. Therefore, fluorescent glass is considered one of the most promising candidates for phosphor conversion materials in the development of high-power LEDs, demonstrating excellent prospects in applications requiring higher brightness, longer lifespan, and greater illumination distances.

[0003] The biggest challenge in preparing fluorescent glass materials by combining phosphors with a glass matrix stems from the interfacial reaction. Effectively controlling the erosion of the phosphor by this reaction, or suppressing its degree, to maximize the preservation of the phosphor's integrity, ultimately determines the overall luminescent performance of the fluorescent glass. The influencing factors for this reaction can be primarily attributed to the compatibility of the phosphor and glass matrix compositions, and secondly, to the heat treatment regime during fluorescent glass synthesis, which is significantly dependent on the glass composition. Therefore, effectively coordinating the phosphor / glass composition compatibility and the heat treatment regime is crucial for preparing high-performance fluorescent glasses. Furthermore, numerous process-related issues also affect the final material's performance, such as the morphology and size of the powder particles, and factors like the sintering atmosphere and environment.

[0004] Currently, most researchers are focused on the direct composite preparation of fluorescent glass with phosphors and commercial glass powders. Chinese patent CN107572777A discloses a method for preparing tellurate transparent fluorescent glass for LED lighting, which involves using Y3Al5O... 12 :Ce 3+Fluorescent glass is prepared by compositing phosphor with a TeO2-Na2CO3-H3BO3-ZnO glass matrix. This method considers refractive index matching to select a low-melting-point tellurate glass matrix and ignores the dominant influence of interfacial reactions. Under low current conditions of 10mA, the highest lumen efficiency of the material is about 100 lm / W. However, this type of glass system has insufficient processability, making it difficult to mass-produce. Chinese patent CN107176791A discloses a high-power fluorescent glass ceramic for lighting and display, its preparation method, and its application, which uses Y3Al5O 12 :Ce 3+ A fluorescent glass-ceramic was prepared by compositing phosphor with a SiO2-A2O-ZnO-MO (A represents alkali metal, M represents alkaline earth metal) glass matrix. This method considered the influence of the heat treatment regime, i.e., lowering the sintering temperature of the fluorescent glass-ceramic, but neglected the coordination between the phosphor / glass matrix composition matching and the heat treatment regime. The luminous efficiency of the encapsulated white LED device was 100 lm / W. Chinese patent CN110128019A discloses a method for preparing and applying a yellow fluorescent glass-ceramic, which uses photopolymerization / 3D printing to obtain (Y,Gd)AG:Ce. 3+ The porous SiO2 glass-based fluorescent glass-ceramic design suffers from poor compatibility between the glass substrate and phosphor, and requires stringent heat treatment conditions (>1000℃, 2h), resulting in an internal quantum efficiency of less than 80% and a luminous efficiency of only 96 lm / W for the encapsulated device. In conclusion, current fluorescent glass designs for high-power LEDs still have many shortcomings. It is difficult to obtain fluorescent glass materials that combine high quantum efficiency of phosphors with high physicochemical stability of glass, and their luminous efficiency and processability still need improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a fluorescent glass material for high-power LEDs, its preparation method, and its application, thereby overcoming the shortcomings of the existing technology. This invention achieves this by harmonizing Y3Al5O 12 :Ce 3+ By matching the composition of phosphor and glass substrate, regulating the corresponding heat treatment regime, and taking into account other process influencing factors to suppress the two-phase interface reaction and reduce the thermal erosion of phosphor, fluorescent glass materials with high internal quantum efficiency and high physicochemical stability can be obtained. Furthermore, by optimizing phosphor concentration and fluorescent glass thickness, the white light spectrum color temperature, color rendering index, and color coordinates can be controlled, while achieving high lumen efficiency for use in high-power LED white light lighting and display fields.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A high-power LED fluorescent glass material includes glass powder and phosphor. The glass powder is a low-melting-point glass powder composed of SiO2, B2O3, Al2O3, CaO, Y2O3, and Na2O in a mass fraction of 40:23:6:8:7:16. The phosphor is Y3Al5O3. 12 :Ce 3+ The emission wavelength is located at ~554nm; the high-power LED fluorescent glass material achieves control over the white light spectrum color temperature, color rendering index, and color coordinates by optimizing the phosphor concentration and fluorescent glass thickness, with a maximum luminous efficiency of ~140lm / W.

[0008] As an improvement, the glass powder is composed of the following components by mass fraction: 40% SiO2, 23% B2O3, 6% Al2O3, 8% CaO, 7% Y2O3, and 16% Na2O, with the sum of the mass fractions of each component being 100%.

[0009] The phosphor has a mass fraction of 10-50% of the total mass of the glass powder.

[0010] The thickness of the fluorescent glass material used in the high-power LED is 0.15-0.40 mm.

[0011] The above-mentioned method for preparing fluorescent glass material for high-power LEDs includes the following steps:

[0012] (1) Weigh the raw materials of glass powder, namely SiO2, B2O3, Al2O3, CaO, Y2O3 and Na2O, according to the mass fraction ratio, and mix them thoroughly in a mortar and grind them to obtain glass mixture;

[0013] (2) After pouring the glass mixture into the corundum crucible, it is placed in a muffle furnace at a temperature of 1500℃ for constant temperature melting for 1 hour. The resulting molten glass liquid is quenched to obtain precursor glass. It is then ball-milled into powder and passed through a 200-mesh sieve to obtain precursor glass powder.

[0014] (3) After mixing the precursor glass powder obtained in step 2 with the phosphor powder evenly, weigh an appropriate amount and place it in a φ20 mold. Press the blank under a pressure of 15MPa, place it in an electric furnace, heat it to 800℃ under atmospheric pressure, and then let it cool with the furnace to make high-power LED fluorescent glass material.

[0015] (4) The high-power LED fluorescent glass material is mechanically processed, cut, polished and ground to a fluorescent glass sheet with a thickness of 0.15-0.40mm.

[0016] The above-mentioned fluorescent glass material for high-power LEDs is used in the fabrication of high-power LED white light lighting or display devices.

[0017] Beneficial effects:

[0018] Compared with the prior art, the present invention provides a high-power LED fluorescent glass material, its preparation method, and its application. First, it selects Y3Al5O... 12 :Ce 3+ SiO2, with extremely low solubility in phosphors, serves as the main glass-forming agent. Secondly, appropriate amounts of Al2O3 and Y2O3 are introduced into the glass matrix to suppress the unidirectional diffusion of Al and Y elements from the phosphor phase to the glass phase. Simultaneously, optimizing the Al2O3 and Y2O3 content avoids the reverse diffusion process of Al and Y elements in the glass phase, i.e., a balanced chemical potential gradient design. Furthermore, Na2O is introduced to lower the glass transition temperature to adjust the heat treatment regime of the fluorescent glass, and CaO is introduced to further ensure the mechanical strength of the glass to meet processing requirements. This addresses the issue of alkali metal Na... + and alkaline earth metals Ca 2+ Regarding the issue of easy diffusion at high temperatures, the system provided by this invention contains [BO4]. - and [AlO4] - The amount of tetrahedrons is used to achieve the tetrahedron avoidance principle and charge balance requirements for Na. + Ca 2+ Self-diffusion suppression was achieved. Ultimately, effective coordination between phosphor / glass composition matching and heat treatment regime was realized, resulting in the preparation of a high-performance fluorescent glass material, Y3Al5O, which combines the high quantum efficiency of the phosphor with the high physicochemical stability of the glass. 12 :Ce 3+ The phosphor is a SiO2-B2O3-Al2O3-CaO-Y2O3-Na2O system glass powder. Therefore, from the perspective of interfacial reaction, effectively coordinating the compositional matching of phosphor / glass matrix and heat treatment regime, while taking into account various influencing factors in the preparation process, to develop a highly efficient and stable fluorescent glass material for high-power LEDs has extremely important theoretical significance and practical value.

[0019] The specific advantages are as follows:

[0020] 1) This invention, based on the perspective of suppressing interfacial reactions, uniquely proposes a glass formulation for two-phase diffusion equilibrium in Y3Al5O. 12 :Ce 3+ Significant results have been achieved in fluorescent glass systems, and it is expected to be extended to various fluorescent glass systems.

[0021] 2) The glass matrix system of the present invention has simple and readily available components, low cost, and the preparation process of fluorescent glass is simple, the heat treatment regime is mild, the processability is strong, and it is easy to carry out large-scale industrial production, and has a broad application market prospect.

[0022] 3) The fluorescent glass material of the present invention, by optimizing the phosphor concentration and the thickness of the fluorescent glass, can easily achieve the control of the white light spectrum color temperature, color rendering index and color coordinates. When encapsulating white LED devices, the highest luminous efficiency can reach ~140lm / W under high power conditions of ~3W. It can be used in the field of high power LED lighting and display. With the combination of heat sink technology, it is expected to be applied to the field of laser lighting and display, and has significant practical and economic value. Attached Figure Description

[0023] Figure 1 The images show actual fluorescent glass samples obtained in Examples 1, 3, 4, 5, and 6 of this invention.

[0024] Figure 2 Example 6 of the present invention and Y3Al5O 12 :Ce 3+ Normalized excitation spectra of phosphors;

[0025] Figure 3 Example 6 of the present invention and Y3Al5O 12 :Ce 3+ Normalized emission spectra of phosphors;

[0026] Figure 4 Example 6 of the present invention and Y3Al5O 12 :Ce 3+ Internal quantum efficiency of phosphors compared to other phosphors;

[0027] Figure 5 Example 6 of the present invention and Y3Al5O 12 :Ce 3+ Fluorescence lifetime of phosphors compared to other phosphors;

[0028] Figure 6 The color coordinate diagrams of the fluorescent glasses prepared in Examples 1, 3, 4, 5, and 6 of this invention under excitation by a 450nm blue light chip are shown.

[0029] Figure 7 The color coordinate diagrams of the fluorescent glasses prepared in Examples 7, 8, 9, 10, and 11 of this invention under 450nm blue light chip excitation are shown. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to embodiments. This description is only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0031] Example

[0032] Weigh out 40wt% SiO2, 23wt% B2O3, 6wt% Al2O3, 8wt% CaO, 7wt% Y2O3 and 16wt% Na2O glass powder to form raw materials. Then, place the weighed raw materials in a mortar and mix them thoroughly, and grind them to obtain a glass mixture. Pour the glass mixture into a corundum crucible and place it in a muffle furnace at a temperature of 1500℃ for constant temperature melting for 1 hour. Quench the obtained molten glass liquid to obtain precursor glass. Roll mill the precursor glass into powder and pass it through a 200-mesh sieve to obtain precursor glass powder.

[0033] The precursor glass powder prepared above was mixed with Y3Al5O at mass fractions of 10 wt% (Example 1), 12 wt% (Example 2), 20 wt% (Example 3), 30 wt% (Example 4), 40 wt% (Example 5), and 50 wt% (Example 6). 12 :Ce 3+ After the phosphor powder is mixed evenly, an appropriate amount is weighed and placed into a φ20 mold. The mixture is pressed into a compact under 15MPa pressure, placed in an electric furnace, and heated to 800℃ under atmospheric pressure before being cooled with the furnace to produce a high-power LED fluorescent glass material. This high-power LED fluorescent glass material is then machined, cut, polished to a thickness of 0.15mm, and then cut into fluorescent glass sheets with a length and width of 2-4mm. These sheets are then encapsulated onto a high-power LED blue light chip. Table 1 shows the color temperature (CCT), color rendering index (CRI), color coordinates (CIE), luminous flux (LF), and luminous efficacy (LE) values ​​for each of Examples 1-6 under a 3W high-power condition.

[0034] Table 1 Performance data of fluorescent glass materials for high-power LEDs in different embodiments

[0035]

[0036]

[0037] Examples 7-11

[0038] The high-power LED fluorescent glass material of Example 6 was cut, polished and ground to different thicknesses, namely 0.15mm (Example 7), 0.20mm (Example 8), 0.25mm (Example 9), 0.30mm (Example 10), and 0.40mm (Example 11). It was then cut into fluorescent glass sheets with a length of 2-4mm and a width of 2-4mm, and directly encapsulated on the high-power LED blue light chip by organic resin bonding.

[0039] Table 2 shows the color temperature (CCT), color rendering index (CRI), color coordinates (CIE), luminous flux (LF), and luminous efficacy (LE) values ​​for each of Examples 7-11 under a high power of 3W.

[0040] Table 2 Performance data of LEDs under different specifications

[0041]

[0042] As shown in Table 2, by adjusting the thickness of the fluorescent glass, the color temperature, color rendering index, and color coordinates can be easily controlled, and the luminous efficiency can reach up to 140 lm / W.

[0043] Depend on Figure 2 and Figure 3 It can be seen that the high-power LED fluorescent glass material prepared in Example 6 and Y3Al5O 12 :Ce 3+ The excitation and emission spectra of the phosphor almost overlapped, and the shape remained unchanged, indicating that Y3Al5O 12 :Ce 3+ The spectral properties of the phosphor are well preserved in the designed glass substrate.

[0044] Depend on Figure 4 The formula for calculating internal quantum efficiency is: Internal quantum efficiency = Total number of photons generated by the material / Total number of photons absorbed. This formula shows that the internal quantum efficiency of the prepared fluorescent glass material is as high as 97%, comparable to Y3Al5O4. 12 :Ce 3+ The phosphors are almost uniform, indicating that the integrity of the phosphors has been well preserved.

[0045] Depend on Figure 5 The fluorescence lifetime calculation formula is: I(t)=I0exp(-t / T), which shows that the fluorescence lifetime of the prepared fluorescent glass material is 61.7ns, which is only about 0.6ns lower than that of the phosphor (62.3ns). This indicates that the designed glass substrate and the corresponding heat treatment process did not have a significant thermal erosion effect on the phosphor.

[0046] Figure 6 and Figure 7 This indicates that the color coordinates of fluorescent glass can be easily controlled by adjusting the concentration and thickness of the phosphor.

[0047] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A fluorescent glass material for high-power LEDs, comprising glass powder and phosphor, characterized in that, The glass powder is a low-melting-point glass powder composed of SiO2, B2O3, Al2O3, CaO, Y2O3, and Na2O in a mass fraction of 40:23:6:8:7:16; the phosphor is Y3Al5O 12 :Ce 3+ The emission wavelength is located at 554nm; the thickness of the fluorescent glass material for high-power LEDs is 0.15-0.40mm; the fluorescent glass material for high-power LEDs achieves control over the white light spectrum color temperature, color rendering index, and color coordinates by optimizing the phosphor concentration and the thickness of the fluorescent glass, with a maximum luminous efficiency of 140lm / W. The method for preparing the fluorescent glass material for high-power LEDs includes the following steps: Step 1: Weigh the raw materials of glass powder, SiO2, B2O3, Al2O3, CaO, Y2O3 and Na2O, according to the mass fraction ratio, and mix them thoroughly in a mortar and grind them to obtain a glass mixture. Step 2: After pouring the glass mixture into the corundum crucible, place it in a muffle furnace at a temperature of 1500℃ for constant temperature melting for 1 hour. Quench the obtained molten glass liquid to obtain precursor glass, then ball mill it into powder and pass it through a 200-mesh sieve to obtain precursor glass powder. Step 3: After mixing the precursor glass powder obtained in Step 2 with the phosphor powder evenly, weigh an appropriate amount and place it into a φ20 mold. Press the preform under a pressure of 15MPa, place it in an electric furnace, heat it to 800℃ under atmospheric pressure, and then let it cool with the furnace to produce high-power LED fluorescent glass material. Step 4: Machining the high-power LED fluorescent glass material described above, cutting, grinding and polishing it to a fluorescent glass sheet with a thickness of 0.15-0.40mm.

2. The fluorescent glass material for high-power LEDs according to claim 1, characterized in that, The mass fraction of the phosphor is 10-50% of the total mass of the glass powder.

3. The application of the high-power LED fluorescent glass material as described in claim 1 in the fabrication of high-power LED white light lighting or display devices.

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