A trapezoidal structure composite fluorescent glass-ceramics for laser illumination and a preparation method thereof

Abstract

This invention discloses a trapezoidal composite fluorescent glass-ceramic for laser illumination and its preparation method. The composite fluorescent glass-ceramic comprises a trapezoidal fluorescent glass and a high thermal conductivity ceramic coating on the outer layer of the fluorescent glass. The trapezoidal fluorescent glass is formed by melting and casting waste glass doped with luminescent ceramic powder, red phosphor, and high thermal conductivity powder. The composite glass-ceramic prepared by this invention achieves high-brightness white light emission under excitation by a 460nm blue LD chip, with a color rendering index of 82-91, and can withstand an excitation power density of 40W / mm². 2 ~55W / mm 2 Its luminous efficacy is 206–265 lm / W, and its thermal conductivity at room temperature is 18–29 Wm. ‑1 k ‑1 .

Description

Technical Field

[0001] This invention relates to the field of fluorescent materials technology, specifically to a trapezoidal composite fluorescent glass-ceramic for laser illumination and its preparation method. Background Technology

[0002] Glass recycling is crucial for resource conservation, energy conservation, and waste management. Waste recycling limits the negative environmental impact of human industrial activities by reducing the production of raw materials. Using unusable waste glass due to breakage or defects, it is mixed with phosphors to produce fluorescent glass for laser lighting.

[0003] Laser lighting is a technology that uses a high-energy beam of light generated by a laser to achieve illumination. Laser lighting has broad application prospects in outdoor plaza lighting, sports venues, stage lighting, architectural lighting, and automotive lighting. However, when fluorescent glass is subjected to high-power-density laser light (greater than 10W / mm²),... 2 When excited by a laser, a large amount of heat accumulates in the laser-irradiated area, mainly due to energy loss during the light conversion process. However, the thermal conductivity of fluorescent glass is approximately 1.0–3.0 W / m². -1 k -1 The low thermal conductivity is insufficient to dissipate the heat quickly, causing the temperature of the fluorescent glass at the laser point to rise sharply, which in turn leads to a decrease in luminescence intensity and the occurrence of luminescence saturation.

[0004] Currently, to achieve better heat dissipation and luminescence efficiency, researchers are designing the structure and thickness of YAG:Ce fluorescent glass films. The literature (On the luminance saturation of phosphor-in-glass (PiG) films for blue-laser-driven white lighting: Effects of the phosphor content and the film thickness. Journal of the European Ceramic Society. 39 1909-1917 (2019)) reports the preparation of PiG films by coating a phosphor-glass mixture slurry onto a sapphire substrate using a doctor blade, achieving a luminous flux of 1048 lm and a maximum saturation threshold of 10.16 W / mm². -2 However, due to insufficient thermal conductivity, thermal quenching occurs, making it difficult to further improve the final luminescence intensity. This is because it only does not contain Y3Al5O3. 12 The Ce luminescent matrix results in a lack of red light, thus leading to low color rendering. Summary of the Invention

[0005] One objective of this invention is to provide a method for preparing a trapezoidal composite fluorescent glass-ceramic for laser lighting, by doping waste glass with Re... 1-x Ce x )3Al5O 12 Red phosphor and high thermal conductivity powder are combined with a trapezoidal structure and an outer layer of high thermal conductivity ceramic to achieve industrial production.

[0006] The second objective of this invention is to provide a trapezoidal composite fluorescent glass-ceramic for laser illumination prepared by the above-mentioned method, which has the advantages of high color rendering index, good heat dissipation performance, and high luminous efficiency.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention also provides a method for preparing a trapezoidal composite fluorescent glass-ceramic for laser illumination, which employs a melt sintering method and specifically includes the following steps:

[0009] (1) After crushing the waste glass, place it in a mortar and grind it into fine particles. Then, put it together with zirconia ceramic balls into a planetary mixer for fine grinding. After ball milling, sieve to obtain waste glass powder.

[0010] (2) The luminescent ceramic powder, red phosphor, high thermal conductivity powder, and waste glass powder are uniformly mixed. The prepared mixed powder is heat-treated at 550–700℃ for 0.5–3 h in a reducing atmosphere to obtain a molten fluorescent glass liquid; the composition of the luminescent ceramic powder is (Re 1-x Ce x )3Al5O 12 Where RE is one or more of Y, Lu, and Tb, and x is Ce 3+ The molar percentage coefficient of doping substitution is 0.0005 ≤ x ≤ 0.01;

[0011] In the fluorescent glass melt, the mass percentage of red phosphor is 1-9%, the mass percentage of high thermal conductivity powder is 10%-60%, and the mass ratio of luminescent ceramic powder to red phosphor is (4-16):1;

[0012] (3) First, place the high thermal conductivity ceramic with trapezoidal grooves on a preheating platform at 300-500℃ for preheating. Then, pour the molten fluorescent glass liquid into the preheated high thermal conductivity ceramic groove, press the glass with a preheated copper plate, and finally polish the upper surface of the fluorescent glass.

[0013] Preferably, the waste glass components mentioned in step (1) mainly include Si, Ca, Na, O, and K.

[0014] Preferably, the red phosphor mentioned in step (2) is a nitride red phosphor CaAlSiN3:Eu 2+ Or fluoride K2(Si / Ge / Ti)F6:Mn 4+ One of them.

[0015] Preferably, the high thermal conductivity powder mentioned in step (2) is one or both of Al2O3 or MgO.

[0016] Preferably, the high thermal conductivity ceramic mentioned in step (3) is one of aluminum nitride, aluminum oxide, magnesium oxide, boron nitride, magnesium aluminum spinel, magnesium fluoride, and calcium fluoride.

[0017] Preferably, in step (3), the cross section of the trapezoidal groove is square, and the longitudinal section of the trapezoidal groove is a trapezoid with a smaller top and a larger bottom, with an upper base of 1-3 mm, a height of 1-3 mm, and a lower base of 1.2-4 mm.

[0018] Preferably, in step (1), the ball milling speed is 100-200 r / min and the ball milling time is 8-12 h.

[0019] Preferably, in step (1), the mesh size of the sieve is 80 to 200 mesh.

[0020] Secondly, the present invention provides a trapezoidal composite fluorescent glass-ceramic for laser illumination prepared by the above preparation method, the composition of which includes trapezoidal fluorescent glass and a high thermal conductivity ceramic coating on the outer layer of the fluorescent glass.

[0021] The composite glass-ceramic, when excited by a 460nm blue LD chip, achieves high-brightness white light emission with a color rendering index of 82-91 and can withstand an excitation power density of 40W / mm². 2 ~55W / mm 2 Its luminous efficacy is 206–265 lm / W, and its thermal conductivity at room temperature is 18–29 Wm. -1 k -1 .

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The composite glass-ceramic prepared in this invention achieves high-brightness white light emission under excitation by a 460nm blue light LD chip, with a color rendering index of 82-91, and can withstand an excitation power density of 40W / mm². 2 ~55W / mm 2 Its luminous efficacy is 206–265 lm / W, and its thermal conductivity is 18–29 Wm. -1 k -1 .

[0024] (2) In this invention, the fluorescent glass-ceramic is designed in a trapezoidal shape. The trapezoidal structure can realize the reflection of light inside the fluorescent glass, improve the blue light conversion efficiency, and at the same time, the trapezoidal structure can better fix the fluorescent glass.

[0025] (3) The present invention uses waste old glass, which can reduce the pollution of glass to the environment. The method of molten casting can realize mass production, which is conducive to the industrialization of the preparation of composite fluorescent glass-ceramics.

[0026] (4) This invention uses a melt casting method to integrate fluorescent glass with an outer layer of high thermal conductivity ceramic. The fluorescent glass and the outer layer of high thermal conductivity ceramic have a large contact area, which improves the heat dissipation capacity of the ceramic, thereby improving the overall thermal conductivity of the composite fluorescent glass-ceramic, making it applicable to high-power lighting devices.

[0027] (5) By doping (Re) into the glass 1-x Ce x )3Al5O 12 Combined with red phosphor, a high color rendering index can be achieved. Doping with high thermal conductivity powder not only effectively improves the thermal conductivity of fluorescent glass, but also promotes light scattering inside the fluorescent glass, promotes the conversion of blue light, and makes the proportion of different wavelengths of light more uniform, thus resulting in a better lighting effect. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the cross-section of the composite fluorescent glass-ceramic in this invention; in the diagram: 1-blue light; 2-(Re 1-x Ce x )3Al5O 12 The light emitted by fluorescent ceramics upon excitation; the light emitted by 3-red phosphors upon excitation; 4-(Re 1-x Ce x )3Al5O 12 Fluorescent ceramics; 5-red phosphor;

[0030] Figure 2 This is a diagram showing the lighting efficiency corresponding to the power density of the composite fluorescent glass-ceramic prepared in Example 1 of this invention. Detailed Implementation

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

[0032] The raw material powders used in the following examples are all commercially available products.

[0033] The waste glass components used in the following examples mainly include Si, Ca, Na, O, and K.

[0034] Example 1

[0035] A trapezoidal composite fluorescent glass-ceramic structure for laser illumination is prepared by melt sintering, specifically including the following steps:

[0036] (1) Hammer the waste glass into small pieces, coarsely grind the broken glass into fine particles in a mortar, and then put it together with ZrO2 ceramic balls into a planetary mixer for fine grinding. The ball milling speed is 160 r / min and the ball milling time is 10 h. Finally, filter the crushed sample through a 200-mesh sieve to obtain waste glass material.

[0037] (2) Luminescent ceramic powder (Lu 0.9995 Ce 0.0005 )3Al5O 12 Red phosphor CaAlSiN3:Eu 2+ High thermal conductivity powder Al2O3 and waste glass powder were uniformly mixed, and the prepared mixed powder was heat-treated at 600℃ for 2 hours in a reducing atmosphere to obtain a molten fluorescent glass melt; wherein (Lu 0.9995 Ce 0.0005 )3Al5O 12 and CaAlSiN3:Eu 2+ The mass ratio is 8:1, the mass of red phosphor is 8 wt% of the mass of the final mixture of fluorescent glass liquid, and the mass of Al2O3 is 40 wt% of the mass of the final mixture of fluorescent glass liquid;

[0038] (3) First, place the high thermal conductivity ceramic with trapezoidal grooves on a preheating platform at 400°C for preheating. Then, pour the molten fluorescent glass liquid into the preheated high thermal conductivity ceramic groove, press the glass with a preheated copper plate, and finally polish the upper surface of the fluorescent glass.

[0039] In this embodiment, the trapezoidal fluorescent glass in the composite fluorescent glass-ceramic has a 1mm square upper surface and a 1.2mm square lower surface. Its longitudinal section is a trapezoid with a smaller top and larger bottom, and a height of 1mm. A schematic diagram of the structure is shown below. Figure 1 As shown.

[0040] A composite fluorescent glass-ceramic material is excited using a blue laser. Excitation is performed by a 460nm blue laser LD chip, which excites the trapezoidal fluorescent glass. The blue light is absorbed and converted into fluorescence. High thermal conductivity powder scatters the light, and the light is reflected within the fluorescent glass, further enhancing the blue light conversion efficiency. The power density reaches 47.8W / mm². 2 It achieves high-brightness white light emission, with a color rendering index of 89, an operating temperature of 88℃, and a luminous efficacy of 268 lm / W (e.g., Figure 2 As shown in the figure, its thermal conductivity is 27.1 W / m². -1 k -1 .

[0041] Example 2

[0042] A trapezoidal composite fluorescent glass-ceramic structure for laser illumination is prepared by melt sintering, specifically including the following steps:

[0043] (1) Hammer the waste glass into small pieces, coarsely grind the broken glass into fine particles in a mortar, and then put it together with ZrO2 ceramic balls into a planetary mixer for fine grinding. The ball milling speed is 200 r / min and the ball milling time is 12 h. Finally, filter the crushed sample through a 150-mesh sieve to obtain waste glass material.

[0044] (2) Luminescent ceramic powder (Y 0.9992 Ce 0.0008 )3Al5O 12 Red phosphor CaAlSiN3:Eu 2+ High thermal conductivity powder MgO and waste glass powder are uniformly mixed, and the prepared mixed powder is heat-treated at 650℃ for 3 hours in a reducing atmosphere to obtain a molten fluorescent glass melt; wherein (Y 0.9992 Ce 0.0008 )3Al5O 12 and CaAlSiN3:Eu 2+ The mass ratio is 12:1, the mass of red phosphor is 6 wt% of the mass of the final mixture of fluorescent glass liquid, and the mass of ZnO is 30 wt% of the mass of the final mixture of fluorescent glass liquid;

[0045] (3) First, place the high thermal conductivity ceramic with trapezoidal grooves on a preheating platform at 500°C for preheating. Then, pour the molten fluorescent glass liquid into the preheated high thermal conductivity ceramic groove, press the glass with a preheated copper plate, and finally polish the upper surface of the fluorescent glass.

[0046] In this embodiment, the trapezoidal fluorescent glass in the composite fluorescent glass-ceramic has a 2mm square upper surface, a 3mm square lower surface, and a longitudinal section that is a trapezoid with a smaller upper section and a larger lower section, with a height of 2mm.

[0047] A composite fluorescent glass-ceramic material is excited using a blue laser. Excitation is performed by a 460nm blue laser LD chip, which excites the trapezoidal fluorescent glass. The blue light is absorbed and converted into fluorescence. High thermal conductivity powder scatters the light, and the light is reflected within the fluorescent glass, further enhancing the blue light conversion efficiency. The power density reaches 42W / mm². 2 It achieves high-brightness white light emission with a color rendering index of 85, an operating temperature of 105℃, a luminous efficiency of 223 lm / W, and a thermal conductivity of 18.4 Wm. -1 k -1 .

[0048] Example 3

[0049] A trapezoidal composite fluorescent glass-ceramic structure for laser illumination is prepared by melt sintering, specifically including the following steps:

[0050] (1) Hammer the waste glass into small pieces, coarsely grind the broken glass into fine particles in a mortar, and then put it into a planetary mixer with ZrO2 ceramic balls for fine grinding. The ball milling speed is 180 r / min and the ball milling time is 8 h. Finally, filter the crushed sample through a 100-mesh sieve to obtain waste glass material.

[0051] (2) The luminescent ceramic powder (Tb 0.999 Ce 0.001 )3Al5O 12 Red phosphor K2(Si / Ge / Ti)F6:Mn 4+ High thermal conductivity powder Al2O3 and waste glass powder were uniformly mixed, and the prepared mixed powder was heat-treated at 550℃ for 2 hours in a reducing atmosphere to obtain a molten fluorescent glass melt; wherein (Tb 0.999 Ce 0.001 )3Al5O 12 and K2(Si / Ge / Ti)F6:Mn 4+ The mass ratio is 16:1, the mass of red phosphor is 6 wt% of the mass of the final mixture of fluorescent glass liquid, and the mass of Al2O3 is 50 wt% of the mass of the final mixture of fluorescent glass liquid;

[0052] (3) First, place the high thermal conductivity ceramic with trapezoidal grooves on a preheating platform at 350°C for preheating. Then, pour the molten fluorescent glass liquid into the preheated high thermal conductivity ceramic groove, press the glass with a preheated copper plate, and finally polish the upper surface of the fluorescent glass.

[0053] In this embodiment, the trapezoidal fluorescent glass in the composite fluorescent glass-ceramic has a 3mm square upper surface, a 4mm square lower surface, a longitudinal section that is a trapezoid with a smaller upper section and a larger lower section, and a height of 2mm.

[0054] A composite fluorescent glass-ceramic material is excited using a blue laser. Excitation is performed by a 460nm blue laser LD chip, which excites the trapezoidal fluorescent glass. The blue light is absorbed and converted into fluorescence. High thermal conductivity powder scatters the light, and the light is reflected within the fluorescent glass, further enhancing the blue light conversion efficiency. The power density reaches 53W / mm². 2 It achieves high-brightness white light emission with a color rendering index of 84, an operating temperature of 85℃, a luminous efficiency of 256 lm / W, and a thermal conductivity of 29.0 Wm. -1 k -1 .

[0055] Example 4

[0056] A trapezoidal composite fluorescent glass-ceramic structure for laser illumination is prepared by melt sintering, specifically including the following steps:

[0057] (1) Hammer the waste glass into small pieces, coarsely grind the broken glass into fine particles in a mortar, and then put it together with ZrO2 ceramic balls into a planetary mixer for fine grinding. The ball milling speed is 120 r / min and the ball milling time is 8 h. Finally, filter the crushed sample through an 80-mesh sieve to obtain waste glass material.

[0058] (2) Luminescent ceramic powder (Lu 0.9993 Ce 0.0007 )3Al5O 12 Red phosphor K2(Si / Ge / Ti)F6:Mn 4+ High thermal conductivity powder Al2O3 and waste glass powder were uniformly mixed, and the prepared particles were heat-treated at 680℃ for 2 hours in a reducing atmosphere to obtain a molten fluorescent glass melt; wherein (Lu 0.9993 Ce 0.0007 )3Al5O 12 and K2(Si / Ge / Ti)F6:Mn 4+ The mass ratio is 4:1, the mass of red phosphor is 9 wt% of the final mixture of fluorescent glass liquid, and the mass of Al2O3 is 20 wt% of the final mixture of fluorescent glass liquid.

[0059] (3) First, place the high thermal conductivity ceramic with trapezoidal grooves on a preheating platform at 300°C for preheating. Then, pour the molten fluorescent glass liquid into the preheated high thermal conductivity ceramic groove, press the glass with a preheated copper plate, and polish the upper surface.

[0060] In this embodiment, the trapezoidal fluorescent glass in the composite fluorescent glass-ceramic has a 3mm square upper surface, a 4mm square lower surface, and a trapezoidal shape with a smaller upper surface and a larger lower surface in longitudinal section, with a height of 3mm.

[0061] A composite fluorescent glass-ceramic material is excited using a blue laser. Excitation is performed by a 460nm blue laser LD chip, which excites the trapezoidal fluorescent glass. The blue light is absorbed and converted into fluorescence. High thermal conductivity powder scatters the light, and the light is reflected within the fluorescent glass, further enhancing the blue light conversion efficiency. The power density reaches 40W / mm². 2 It achieves high-brightness white light emission with a color rendering index of 91, an operating temperature of 95℃, a luminous efficiency of 206 lm / W, and a thermal conductivity of 24.2 Wm. -1 k -1 .

[0062] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a trapezoidal composite fluorescent glass-ceramic for laser illumination, characterized in that, The melting sintering method includes the following steps: (1) After crushing the waste glass, place it in a mortar and grind it into fine particles. Then, put it together with zirconia ceramic balls into a planetary mixer for fine grinding. After ball milling, sieve to obtain waste glass powder. (2) The luminescent ceramic powder, red phosphor, high thermal conductivity powder, and waste glass powder are uniformly mixed. The prepared mixed powder is heat-treated at 550–700℃ for 0.5–3 h in a reducing atmosphere to obtain a molten fluorescent glass liquid; the composition of the luminescent ceramic powder is (Re 1-x Ce x )3Al5O 12 Where R is one or more of Y, Lu, and Tb, and x is Ce 3+ The molar percentage coefficient of doping substitution is 0.0005 ≤ x ≤ 0.01; In the fluorescent glass melt, the mass percentage of red phosphor is 1-9%, the mass percentage of high thermal conductivity powder is 10%-60%, and the mass ratio of luminescent ceramic powder to red phosphor is (4-16):1; (3) First, place the high thermal conductivity ceramic with trapezoidal grooves on a preheating platform at 300-500℃ for preheating. Then, pour the molten fluorescent glass liquid into the preheated high thermal conductivity ceramic groove, press the glass with a preheated copper plate, and finally polish the upper surface of the fluorescent glass.

2. The method for preparing a trapezoidal composite fluorescent glass-ceramic for laser illumination according to claim 1, characterized in that, The waste glass components mentioned in step (1) mainly include Si, Ca, Na, O, and K.

3. The method for preparing a trapezoidal composite fluorescent glass-ceramic for laser illumination according to claim 1, characterized in that, The red phosphor mentioned in step (2) is a nitride red phosphor CaAlSiN3:Eu 2+ Or fluoride K2(Si / Ge / Ti)F6:Mn 4+ One of them.

4. The method for preparing a trapezoidal composite fluorescent glass-ceramic for laser illumination according to claim 1, characterized in that, The high thermal conductivity powder mentioned in step (2) is one or both of Al2O3 or MgO.

5. The method for preparing a trapezoidal composite fluorescent glass-ceramic for laser illumination according to claim 1, characterized in that, The high thermal conductivity ceramic mentioned in step (3) is one of aluminum nitride, aluminum oxide, magnesium oxide, boron nitride, magnesium aluminum spinel, magnesium fluoride, and calcium fluoride.

6. The method for preparing a trapezoidal composite fluorescent glass-ceramic for laser illumination according to claim 1, characterized in that, In step (3), the cross section of the trapezoidal groove is square, and the longitudinal section of the trapezoidal groove is a trapezoid with a smaller top and a larger bottom, with an upper base of 1-3 mm, a height of 1-3 mm, and a lower base of 1.2-4 mm.

7. The method for preparing a trapezoidal composite fluorescent glass-ceramic for laser illumination according to claim 1, characterized in that, In step (1), the ball milling speed is 100-200 r / min and the ball milling time is 8-12 h.

8. The method for preparing a trapezoidal composite fluorescent glass-ceramic for laser illumination according to claim 1, characterized in that, In step (1), the sieve mesh size is 80 to 200 mesh.

9. A trapezoidal composite fluorescent glass-ceramic for laser illumination prepared by the method according to any one of claims 1 to 8, characterized in that, Its composition includes trapezoidal fluorescent glass and a high thermal conductivity ceramic coating on the outside of the fluorescent glass.

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