High-thermal-conductivity reflective fluorescent powder-glass composite color conversion structure, preparation method and application thereof

Abstract

The application discloses a high-thermal-conductivity reflective fluorescent powder-glass composite color conversion structure and a preparation method and application thereof, and relates to the technical field of laser lighting and photoelectric functional materials. The composite color conversion structure comprises a substrate, a reflective intermediate layer and a fluorescent conversion layer; the reflective intermediate layer at least comprises high-reflectivity particles, high-thermal-conductivity particles and a glass phase binder, and the fluorescent conversion layer at least comprises fluorescent powder and a glass matrix, and the thermal conductivity of the substrate is not less than 50 Wm ‑1 ·K 1 The application further provides a space splicing type dynamic color wheel. The technical scheme can take into account higher interface reflectivity, heat dissipation efficiency and structural stability, and is suitable for fields such as laser lighting.

Description

Technical Field

[0001] This invention relates to the field of laser lighting and optoelectronic functional materials technology, specifically to a high thermal conductivity and reflectivity phosphor-glass composite color conversion structure, its preparation method, and its application. Background Technology

[0002] Laser diodes, with their advantages of high power density, good directionality, and high brightness, have become important excitation sources for high-brightness lighting, automotive lighting, projection displays, and special light sources. However, the small laser excitation spot and high local power density make traditional color converters prone to severe local heat accumulation during operation, leading to thermal quenching, brightness reduction, color drift, and structural failure.

[0003] In existing technologies, common color converters include phosphor-silicone structures, phosphor-glass blocks, fluorescent ceramics, and phosphor-glass films. Among these, phosphor-silicone structures have insufficient heat resistance; ordinary phosphor-glass systems have long heat dissipation paths and low thermal conductivity; metallic Al reflective substrates are prone to oxidation; Al2O3 substrates are stable but have insufficient thermal conductivity; and dual-color mixed structures are prone to reabsorption losses.

[0004] Therefore, a reflective composite color conversion structure that can simultaneously achieve high reflectivity, rapid heat dissipation, structural robustness, and low reabsorption loss is needed, and the corresponding material combinations, component ranges, and preparation methods are provided. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a high thermal conductivity and reflectivity phosphor-glass composite color conversion structure and its preparation method, which addresses the problems of unreasonable heat dissipation path, low interface reflectivity, serious heat accumulation and easy reabsorption in dual-color systems of existing laser color converters, so as to achieve a balance between light extraction efficiency, thermal stability and color quality under high power laser excitation.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a high thermal conductivity and reflectivity phosphor-glass composite color conversion structure, comprising a substrate, a reflective intermediate layer disposed on the surface of the substrate, and a fluorescence conversion layer disposed on the reflective intermediate layer; the reflective intermediate layer comprises at least high reflectivity particles, high thermal conductivity particles, and a glass phase binder; the fluorescence conversion layer comprises at least phosphor and a glass substrate; the thermal conductivity of the substrate is not less than 50 W·m. -1 ·K -1 .

[0007] Furthermore, the high reflectivity particles are selected from one or at least two of TiO2, ZrO2, BaSO4, and Al2O3-coated TiO2; the high thermal conductivity particles are selected from one or at least two of Al2O3, AlN, BN, Si3N4, and SiC.

[0008] Furthermore, the mass ratio of high reflectivity particles, high thermal conductivity particles and glass phase binder in the reflective intermediate layer is 6-20:0.5-5:0.5-5, preferably 8-15:0.8-3:1-3, and more preferably 10:1:2.

[0009] Furthermore, the thickness of the reflective intermediate layer is 10–80 μm, preferably 20–60 μm, and more preferably 40 μm.

[0010] Furthermore, the substrate is selected from AlN, Al2O3, Si3N4, or a composite ceramic substrate, preferably an AlN substrate; when an AlN substrate is used, its thermal conductivity is preferably 100–250 W·m. -1 ·K -1 .

[0011] Furthermore, the glass substrate is lithium aluminum silicate glass or lithium aluminum silicate microcrystalline glass, containing SiO2, Li2O, Al2O3, and one or at least two of P2O5, Na2O, K2O, MgO, ZrO2, and CaO.

[0012] Furthermore, the phosphor in the fluorescence conversion layer is preferably Y3Al5O. 12 :Ce 3+ and / or Lu3Al5O 12 :Ce 3+ The phosphor has a mass fraction of 40 wt% to 85 wt%, preferably 50 wt% to 80 wt%, and more preferably 60 wt%. The thickness of the fluorescence conversion layer is 60 to 300 μm, preferably 80 to 180 μm, and more preferably 120 μm.

[0013] Furthermore, the glass substrate contains in-situ precipitated lithium disilicate crystals after sintering.

[0014] This invention also provides a spatially spliced ​​dynamic color wheel structure, in which fluorescence conversion layers of different emission bands are partitioned and arranged on the same rotating color wheel, reducing reabsorption between different phosphors through spatial separation. The first luminescent region uses Y3Al5O 12 :Ce 3+ The second luminescent region uses Lu3Al5O 12 :Ce 3+ The angle ratio between the two is 5:1 to 1:5, preferably 2:1.

[0015] The present invention also provides a method for preparing the above-mentioned composite color conversion structure, comprising the following steps: (1) Preparation of glass powder; (2) High reflectivity particles, high thermal conductivity particles, glass phase binder and organic carrier are mixed to prepare reflective paste; (3) The phosphor is mixed with glass powder and organic carrier to prepare a fluorescent paste; (4) Print the reflective paste onto the substrate surface and dry it; (5) Print the fluorescent paste onto the surface of the reflective intermediate layer and dry it; (6) Co-fire or sintering is performed to obtain the composite color conversion structure.

[0016] Further, the sintering temperature is 780–920 °C, preferably 820–900 °C. The reflective paste and / or fluorescent paste are deposited by screen printing, scraping, spraying, or dispensing.

[0017] The present invention further provides the application of the above-mentioned composite color conversion structure or spatial splicing dynamic color wheel in laser lighting, projection display, automotive lighting, stage lighting or high-brightness directional lighting.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. By constructing a three-layer composite structure of "high thermal conductivity substrate / reflective intermediate layer / fluorescence conversion layer", the heat conduction path is shortened, which is conducive to the rapid removal of heat from the fluorescence conversion layer and improves the overall heat dissipation efficiency of the structure.

[0019] 2. By simultaneously introducing high reflectivity particles and high thermal conductivity particles into the reflective intermediate layer, the reflective intermediate layer can have both light reflection and thermal conductivity functions, which is beneficial to simultaneously improve the interface reflectivity and vertical thermal conductivity efficiency.

[0020] 3. By using a lithium aluminum silicate glass substrate to coat and fix phosphor particles, and then forming lithium disilicate crystals after sintering, it is beneficial to improve the structural robustness and thermal stability of the phosphor conversion layer.

[0021] 4. By adopting a spatial splicing dynamic color wheel design, the fluorescence regions of different emission bands are spatially separated from each other, which helps to reduce the reabsorption loss between different phosphors and improve the overall color quality.

[0022] 5. In the preferred embodiment, the thermal conductivity of Y-PiTA and Lu-PiTA can reach 74.3 W·m and 69.9 W·m, respectively. -1 ·K -1The maximum luminous flux can reach 2658 and 4004 lm respectively; the dynamic color wheel white light output can reach 4528 lm, and the color rendering index can reach 71.3. Attached Figure Description Figure 1 This is a graph showing the luminous flux versus power curves of the structures obtained from LuAG:Ce phosphors in Examples 1-3 of this invention. Figure 2 This is a graph showing the luminous flux versus power curves of the structures obtained from LuAG:Ce phosphors in Examples 1-3 of this invention. Figure 3 This is a graph showing the reflectivity variation of the reflective intermediate layer in Examples 1-3 of this invention; Figure 4 These are the thermal conductivity test results of the structures obtained in Examples 1-3 of this invention; Figure 5 The luminous flux and color rendering index of color wheels spliced ​​in different proportions in this invention; Figure 6 This is a top view of the color wheels spliced ​​in different proportions in this invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 AlN substrate is used as the base material; the mass ratio of high-reflectivity particles, high-thermal-conductivity particles, and glass phase binder in the reflective interlayer is 6:0.5:0.5; the thickness of the reflective interlayer is 20 μm. The fluorescence conversion layer uses a lithium aluminum silicate glass substrate, with a phosphor mass fraction of 40 wt% and a film thickness of 60 μm. The phosphor can be Y3Al5O3. 12 :Ce 3+ Or Lu3Al5O 12 :Ce 3+ .

[0025] Tests have shown that Y3Al5O is used. 12 :Ce 3+ At that time, the thermal conductivity of the obtained structure can reach 98.6 W·m. -1 ·K -1 The maximum luminous flux can reach 2128 lm; it uses Lu3Al5O 12 :Ce 3+ At that time, the thermal conductivity of the obtained structure can reach 89.4 W·m.-1 ·K -1 The maximum luminous flux can reach 2994 lm.

[0026] Example 2 AlN substrate is used as the substrate material; the mass ratio of TiO2:Al2O3:glass phase binder in the reflective intermediate layer is 10:1:2, and the thickness is 40 μm; the phosphor mass fraction in the fluorescence conversion layer is 60 wt%, and the film thickness is 120 μm. The phosphor can be Y3Al5O3. 12 :Ce 3+ Or Lu3Al5O 12 :Ce 3+ .

[0027] Tests have shown that Y3Al5O is used. 12 :Ce 3+ At that time, the thermal conductivity of the obtained structure can reach 74.3 W·m. -1 ·K -1 The maximum luminous flux can reach 2658 lm; it uses Lu3Al5O 12 :Ce 3+ At that time, the thermal conductivity of the obtained structure can reach 69.9 W·m. -1 ·K -1 The maximum luminous flux can reach 4004 lm. The above performance data is only used to illustrate the technical effects achievable by this invention and does not constitute a limitation on the scope of protection of this invention.

[0028] Example 3 The substrate is AlN. The mass ratio of high-reflectivity particles, high-thermal-conductivity particles, and glass phase binder in the reflective interlayer is 20:5:5. The thickness of the reflective interlayer is 60 μm. The phosphor in the fluorescence conversion layer has a phosphor mass fraction of 80 wt% and a film thickness of 300 μm. The phosphor can be Y3Al5O3. 12 :Ce 3+ Or Lu3Al5O 12 :Ce 3+ .

[0029] Tests have shown that Y3Al5O is used. 12 :Ce 3+ At that time, the thermal conductivity of the obtained structure can reach 36.7 W·m. -1 ·K -1 The maximum luminous flux can reach 1396 lm; it uses Lu3Al5O 12 :Ce 3+ At that time, the thermal conductivity of the obtained structure can reach 32.4 W·m. -1 ·K -1 The maximum luminous flux can reach 2056 lm.

[0030] Example 4 Based on the composite color conversion structure described in Embodiment 2, Y3Al5O 12 :Ce 3+ The first luminescent region and containing Lu3Al5O 12 :Ce 3+ The second luminescent area is configured as separate sectors and fixed on a rotating color wheel. The angle ratio between the first and second luminescent areas is 5:1 to 1:5; preferably 2:1.

[0031] Under 62 W laser excitation, this dynamic color wheel can achieve approximately 4528 lm of white light output, with a color rendering index of approximately 71.3. The above performance data are only used to illustrate the technical effects achievable by this invention and do not constitute a limitation on the scope of protection of this invention.

[0032] Summary of Implementation Parameters

[0033] Preparation process implementation method I. Glass Matrix Preparation Lithium aluminum silicate precursor glass can be prepared using a melt-quench method. SiO2, Li2O, Al2O3, P2O5, Na2O, K2O, MgO, ZrO2, and CaO are mixed in a designed stoichiometric ratio and melted at 1450 °C for 1 h, followed by quenching. The resulting glass floc is dried, ball-milled for 6 h, and sieved to obtain precursor glass powder.

[0034] II. Preparation of Organic Carriers Diethylene glycol monobutyl ether acetate, terpineol, and ethyl cellulose can be mixed and stirred at 80 °C until a homogeneous viscous solution is formed, which can then be used as an organic carrier.

[0035] III. Preparation of Reflective and Fluorescent Pastes An organic carrier is mixed with glass powder, high thermal conductivity particles and high reflectivity particles to prepare a reflective paste, wherein the glass powder forms a glass phase binder in the reflective intermediate layer during the subsequent sintering process; an organic carrier is mixed with glass powder and phosphor to prepare a fluorescent paste.

[0036] IV. Printing and Sintering First, reflective paste is printed onto the substrate surface and dried to form a reflective intermediate layer; then, fluorescent paste is printed onto the surface of the reflective intermediate layer and dried to form a fluorescent conversion layer; finally, co-firing or sintering is performed to obtain a composite color conversion structure. The sintering temperature can be 780–920 °C, preferably 820–900 °C. In other embodiments, the printing can be replaced by scraping, spraying, or dispensing deposition.

[0037] V. Material Structural Characteristics After sintering, the main diffraction peak of the phosphor remains stable, and lithium disilicate crystals can form in the glass matrix, which helps to enhance the mechanical integrity and thermal stability of the composite structure. The phosphor particles can be uniformly embedded in the lithium aluminum silicate glass matrix to form a relatively dense composite structure.

[0038] Application Notes The high thermal conductivity and reflectivity phosphor-glass composite color conversion structure and spatially spliced ​​dynamic color wheel provided by this invention can be applied to fields such as laser lighting, projection display, automotive lighting, stage lighting, and high-brightness directional lighting. This invention is particularly valuable in high-power laser excitation scenarios.

[0039] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high thermal conductivity and reflectivity phosphor-glass composite color conversion structure, characterized in that, It includes a substrate, a reflective intermediate layer disposed on the surface of the substrate, and a fluorescence conversion layer disposed on the reflective intermediate layer; The reflective intermediate layer comprises high-reflectivity particles, high-thermal-conductivity particles, and a glass phase binder. The high-reflectivity particles are selected from one or at least two of TiO2, ZrO2, BaSO4, and Al2O3-coated TiO2. The high-thermal-conductivity particles are selected from one or at least two of Al2O3, AlN, BN, Si3N4, and SiC. The mass ratio of the high-reflectivity particles, high-thermal-conductivity particles, and glass phase binder is 6–20:0.5–5:0.5–5. The thickness of the reflective intermediate layer is 10–80 μm. The fluorescence conversion layer comprises phosphor and a glass substrate, wherein the glass substrate is lithium aluminum silicate glass or lithium aluminum silicate microcrystalline glass, and the glass substrate contains in-situ precipitated lithium disilicate crystals after sintering. The thermal conductivity of the substrate is not less than 50 W·m. -1 ·K -1 The phosphor has a mass fraction of 40wt% to 85wt% in the fluorescence conversion layer, and the thickness of the fluorescence conversion layer is 60 to 300 μm.

2. The composite color conversion structure according to claim 1, characterized in that, The mass ratio of the high-reflectivity particles, high-thermal-conductivity particles and glass phase binder is 8-15:0.8-3:1-3, and the thickness of the reflective intermediate layer is 20-60 μm.

3. The composite color conversion structure according to claim 1 or 2, characterized in that, The substrate is selected from AlN, Al2O3, Si3N4, or a composite ceramic substrate; when the substrate is an AlN substrate, its thermal conductivity is 100–250 W·m. -1 ·K -1 .

4. The composite color conversion structure according to any one of claims 1 to 3, characterized in that, The glass substrate comprises SiO2, Li2O, Al2O3, and one or at least two of P2O5, Na2O, K2O, MgO, ZrO2, and CaO.

5. The composite color conversion structure according to any one of claims 1 to 4, characterized in that, The phosphor is selected from one or at least two Ce-doped garnet phosphors; the mass fraction of the phosphor in the fluorescence conversion layer is 50 wt% to 80 wt%, the thickness of the fluorescence conversion layer is 80 to 180 μm, and the phosphor is Y3Al5O 12 :Ce 3+ and / or Lu3Al5O 12 :Ce 3+ .

6. A spatially spliced ​​dynamic color wheel, characterized in that, The first luminescent region and the second luminescent region are formed by the composite color conversion structure according to any one of claims 1 to 5, wherein the first luminescent region and the second luminescent region are spatially separated from each other and each contains phosphors of different emission bands.

7. The spatially spliced ​​dynamic color wheel according to claim 6, characterized in that, The first luminescent region contains Y3Al5O 12 :Ce 3+ The second luminescent region contains Lu3Al5O 12 :Ce 3+ The angle ratio between the first luminous region and the second luminous region is 5:1 to 1:

5.

8. A method for preparing the composite color conversion structure according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Preparation of glass powder; (2) High reflectivity particles, high thermal conductivity particles, glass phase binder and organic carrier are mixed to prepare reflective paste; (3) The phosphor is mixed with glass powder and organic carrier to prepare a fluorescent paste; (4) Print the reflective paste onto the substrate surface and dry it; (5) Print the fluorescent paste onto the surface of the reflective intermediate layer and dry it; (6) Perform co-firing or sintering to obtain the composite color conversion structure; The sintering temperature is 780–920 °C; the reflective paste and / or fluorescent paste are deposited by screen printing, scraping, spraying or dispensing.

9. The application of the composite color conversion structure according to any one of claims 1 to 5 or the spatial splicing dynamic color wheel according to any one of claims 6 to 7 in laser lighting, projection display, automotive lighting, stage lighting or high-brightness directional lighting.

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