A glass-based fluorescent ceramic material, its preparation method and application

Abstract

This invention discloses a glass-based fluorescent ceramic material, its preparation method, and its applications. The glass-based fluorescent ceramic material of this invention comprises a substrate and a fluorescent glass film, wherein the fluorescent glass film is disposed on at least one surface of the substrate; the substrate is selected from garnet-based fluorescent ceramics; the fluorescent glass film comprises at least a glassy component and a fluorescent element; the thickness ratio of the substrate to the fluorescent glass film is 20:1-50:1. The glass-based fluorescent ceramic material of this invention has outstanding advantages such as good thermal stability and good optical performance. When used for encapsulation to obtain LED light sources, it achieves high luminous efficacy and high color rendering index (CRI) illumination.

Description

Technical Field

[0001] This invention relates to a glass-based fluorescent ceramic material, its preparation method, and its application, belonging to the field of solid-state luminescent materials. Background Technology

[0002] White light-emitting diodes (wLEDs) have been widely used in solid-state lighting due to their advantages such as environmental friendliness, high efficiency, long lifespan, and energy saving. Currently, the manufacturing method for commercial white LEDs involves combining a blue LED chip with YAG:Ce yellow phosphor and embedding it in silicone or organic resin. However, for high-power wLEDs, the heat resistance and thermal conductivity (0.1–0.4 W / m²) of the organic encapsulation material are crucial. -1 K -1 The light emission level is low, which can lead to a decrease in luminous efficacy and severe discoloration after prolonged use.

[0003] Compared to organic resins or silicone, glass has higher thermal conductivity and better chemical stability, effectively protecting phosphor particles and thus improving luminous efficiency and extending lifespan. Currently, much research focuses on fluorescent glass and glass-based fluorescent glass films. Patent CN105399325 discloses a Ce:YAG fluorescent glass for white LEDs and its preparation method. The method involves uniformly mixing PbO, B2O3, ZnO, and SiO2, melting the mixture at a high temperature (around 1000℃), water quenching to obtain glass fragments, and then mixing the broken glass fragments with YAG:Ce phosphor and sintering to form fluorescent glass. This fluorescent glass uses the toxic raw material PbO, which is detrimental to safe production. Furthermore, the light obtained using a single YAG:Ce yellow phosphor is cool white light. This white light, lacking red components, often exhibits high color temperature and low color rendering index (CRI), making it unsuitable for lighting applications requiring high CRI and low color temperature.

[0004] Compared to fluorescent glass or glass-based fluorescent glass films, fluorescent ceramics are considered the best choice for phosphor converters due to their superior thermal conductivity and thermal stability. Therefore, developing a high CRI fluorescent glass film based on YAG-based fluorescent ceramics is of great significance. Summary of the Invention

[0005] To address the above problems, the present invention provides the following technical solution:

[0006] A glass-based fluorescent ceramic material includes a substrate and a fluorescent glass film disposed on at least one surface of the substrate, for example, on either one surface or on both surfaces.

[0007] According to an embodiment of the present invention, the substrate is selected from garnet-based fluorescent ceramics. Preferably, the garnet-based fluorescent ceramic is selected from, for example, YAG-based fluorescent ceramics, LuAG-based fluorescent ceramics, such as YAG:Ce, LuAG:Ce, and YLuAG:Ce.

[0008] According to an embodiment of the present invention, the thickness ratio of the substrate to the fluorescent glass film is 20:1 to 50:1, for example, 50:1.

[0009] According to an embodiment of the present invention, the fluorescent glass film comprises at least a glass body and a fluorescent element.

[0010] According to an embodiment of the present invention, the fluorescent element is uniformly distributed in the glass body.

[0011] According to an embodiment of the present invention, the content of the fluorescent element in the fluorescent glass film is 0.003-0.009 wt%, for example, 0.006 wt%.

[0012] According to an embodiment of the present invention, the glass body is selected from Bi2O3-B2O3-SiO2-Na2O-M x O glass system, in which oxide M x In O, M is selected from at least one of Li, Zn, Al, P, Ba, and Ga, and x is selected from 1 to 3, for example, 1, 2, and 3.

[0013] According to an embodiment of the present invention, the fluorescent element is selected from elements that exhibit red fluorescence, such as Eu. 2+ Mn 2 + Mn 4+ At least one of them.

[0014] Preferably, the element with red fluorescence is provided by a phosphor. Further, the phosphor is selected from (Sr,Ca)AlSiN3:Eu 2+ Phosphor, CaAlSiN3:Eu 2+ Phosphor, Sr2Si5N8:Eu 2+ At least one of the fluorescent powders.

[0015] According to an embodiment of the present invention, the fluorescent glass film is prepared by mixing the powder of the glass body with the phosphor and sintering it.

[0016] Preferably, the phosphor accounts for 0.1 wt% to 80 wt% of the total mass of the glass body powder and phosphor, for example, 50 wt%.

[0017] Preferably, the particle size of the glass body powder is no greater than 80 micrometers, for example, 23 micrometers.

[0018] This invention also provides a method for preparing the above-mentioned glass-based fluorescent ceramic material, the method comprising the following steps:

[0019] (1) Preparation of glass powder: glass powder is obtained by melting glass and then rapidly cooling it.

[0020] (2) Mix the phosphor with the glass powder obtained in step (1) and add an organic solvent to prepare a slurry;

[0021] (3) The slurry from step (2) is coated onto the substrate surface, dried, and sintered to obtain the glass-based composite fluorescent ceramic.

[0022] According to an embodiment of the present invention, in step (1), the glass body has the meaning as described above. Preferably, the glass body can be prepared by methods known in the art, for example, by mixing raw materials with a stoichiometric ratio and then melting them at a high temperature. In the present invention, the high-temperature melting can be performed at a temperature known in the art, for example, above 800°C, or even 950°C or 1000°C. Preferably, after high-temperature melting, the temperature can be maintained for a period of time, for example, 0 min to 60 min, or even 30 min.

[0023] According to an embodiment of the present invention, in step (1), the melting temperature is above 800°C, preferably 850-950°C, for example 950°C or 1000°C.

[0024] According to an embodiment of the present invention, in step (1), the melting time is 30 min to 120 min, for example, 60 min.

[0025] According to an embodiment of the present invention, in step (1), after melting, a heat preservation treatment can also be performed. The heat preservation treatment refers to heat preservation at the melting temperature for a time of 10 min to 60 min, for example, 30 min.

[0026] According to an embodiment of the present invention, in step (1), the rapid cooling process includes rapidly cooling the molten glass body at 0-100°C, optionally followed by crushing and grinding. Preferably, after grinding, the glass powder is passed through a 200-300 mesh sieve.

[0027] According to an embodiment of the present invention, in step (2), the organic solvent is selected from alcohols and cellulose. Preferably, the alcohol is selected from at least one of terpineol and isopropanol. Preferably, the cellulose is selected from ethyl cellulose.

[0028] According to an embodiment of the present invention, in step (2), the mass ratio of oleyl alcohol to cellulose is 1-30:1, for example, 20:1.

[0029] For example, the organic solvent is composed of terpineol and ethyl cellulose, with a mass ratio of terpineol to ethyl cellulose of 20:1.

[0030] According to an embodiment of the present invention, the amount of organic solvent used is not specifically limited, as long as the slurry can be obtained. For example, the mass ratio of glass powder to organic solvent is 1:3.

[0031] According to an embodiment of the present invention, in step (2), the phosphor accounts for 0.1wt%-80wt% of the total mass of the glass powder and the phosphor, for example, 50wt%.

[0032] According to an embodiment of the present invention, in step (3), the amount of slurry and substrate used during coating is not specifically limited, as long as the glass-based composite fluorescent ceramic can be obtained. For example, the mass ratio of the slurry to the substrate is 2:3.

[0033] According to an embodiment of the present invention, in step (3), the drying refers to being carried out at a temperature below 100°C, for example, 70°C.

[0034] According to an embodiment of the present invention, in step (3), the sintering conditions include: a sintering temperature of 400℃-600℃ and a holding time of 10-30min. For example, the sintering temperature is 530℃ and the holding time is 30min.

[0035] The present invention also provides the application of the above-mentioned glass-based fluorescent ceramic material in high-power LEDs.

[0036] According to an embodiment of the present invention, the high-power LED refers to an LED with a rated current exceeding 20mA, such as a 670mA constant current drive.

[0037] The beneficial effects of this invention are:

[0038] (1) This invention develops a glass with a low melting temperature, solving the problem of high-temperature glass erosion of nitride red phosphors, and successfully prepares glass-based fluorescent ceramic materials. The prepared glass-based fluorescent ceramic materials have outstanding advantages such as good thermal stability and good optical properties.

[0039] (2) The glass-based fluorescent ceramic material described in this invention uses YAG-based fluorescent ceramic as a substrate, which has good heat dissipation effect. Attached Figure Description

[0040] Figure 1 The transmittance curve of the glass illustrates that the prepared glass has high transmittance.

[0041] Figure 2The emission spectra of the glass-based fluorescent ceramic materials in Examples 1-4 are shown below: a distinct emission peak is observed at 603 nm, which is due to the (Sr,Ca)AlSiN3:Eu 2+ The main emission peak, and with (Sr,Ca)AlSiN3:Eu 2+ As the concentration of phosphor increases, the emission peak of the red phosphor becomes stronger and undergoes a redshift, which is consistent with reality. Detailed Implementation

[0042] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0043] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0044] Example 1

[0045] The preparation method of glass-based fluorescent ceramic materials is as follows:

[0046] (1) Preparation of glass powder: Take glass raw materials according to 58wt% Bi2O3, 20wt% B2O3, 10wt% SiO2, 4wt% ZnO, 3wt% Al2O3, 4wt% Na2O, and 1wt% Li2O and put them into an agate mortar. Mix the above raw materials evenly and put them into a platinum crucible. After the muffle furnace is heated to 950℃, put the platinum crucible into it and keep it at that temperature for 60 minutes. After the temperature is kept, take out the platinum crucible. At this time, the glass melt in the platinum crucible is rapidly cooled in the air to obtain glass blocks. After the glass blocks are broken, put them into a mortar and grind them. Pass them through a 300-mesh sieve to obtain glass powder.

[0047] (2)(Sr,Ca)AlSiN3:Eu 2+ The red phosphor and the glass powder from step (1) were weighed in a 1:1 mass ratio, mixed evenly, and then an organic solvent (composed of terpineol and ethyl cellulose, with a mass ratio of 20:1 for terpineol and ethyl cellulose, and a mass ratio of 3:1 for the organic solvent and glass powder) was added to prepare a slurry. This slurry was then spin-coated onto one surface of a YAG:Ce ceramic substrate to obtain a glass film, wherein the thickness ratio of the glass film to the ceramic substrate was 1:50. The coated ceramic sheet was then dried in an oven at 70°C for 8 hours. Finally, the dried ceramic sheet was sintered in a muffle furnace at 530°C for 30 minutes to obtain the glass-based fluorescent ceramic material.

[0048] The glass-based fluorescent ceramic material of this embodiment is encapsulated with a blue light chip to form an LED device. At room temperature, with a constant current of 670mA applied, the measured performance parameters are as follows:

[0049] Luminous efficacy: 98.35 lm / W; Color rendering index: 72.2.

[0050] Example 2

[0051] The preparation method of glass-based fluorescent ceramic materials is as follows:

[0052] (1) Preparation of glass powder: Take glass raw materials according to 58wt% Bi2O3, 20wt% B2O3, 10wt% SiO2, 4wt% ZnO, 3wt% Al2O3, 4wt% Na2O, and 1wt% Li2O and put them into an agate mortar. Mix the above raw materials evenly and put them into a platinum crucible. After the muffle furnace is heated to 950℃, put the platinum crucible into it and keep it at that temperature for 60 minutes. After the temperature is kept, take out the platinum crucible. At this time, the glass melt in the platinum crucible is rapidly cooled in the air to obtain glass blocks. After the glass blocks are broken, put them into a mortar and grind them. Pass them through a 300-mesh sieve to obtain glass powder.

[0053] (2)(Sr,Ca)AlSiN3:Eu 2+ The red phosphor and the glass powder from step (1) were weighed in a ratio of 1:1.5 (mass ratio), mixed evenly, and then an organic solvent (composed of terpineol and ethyl cellulose, with a mass ratio of 20:1 for terpineol and ethyl cellulose, and a mass ratio of 3:1 for the organic solvent and glass powder) was added to prepare a slurry. This slurry was then spin-coated onto one surface of a YAG:Ce ceramic substrate to obtain a glass film, wherein the thickness ratio of the glass film to the ceramic substrate was 1:50. The coated ceramic sheet was then dried in an oven at 70°C for 8 hours. Finally, the dried ceramic sheet was sintered in a muffle furnace at 530°C for 30 minutes to obtain the glass-based fluorescent ceramic material.

[0054] The glass-based fluorescent ceramic material and blue light chip of this embodiment are packaged into an LED device. At room temperature, a constant current of 670mA is applied, and the measured performance parameters are as follows:

[0055] Luminous efficacy: 115.99 lm / W; Color rendering index: 74.5.

[0056] As can be seen, the glass-based fluorescent ceramic material in this embodiment has excellent light and color performance, which can meet the needs of high-power LED lighting.

[0057] Example 3

[0058] The preparation method of glass-based fluorescent ceramic materials is as follows:

[0059] (1) Preparation of glass powder: Take glass raw materials with 58wt% Bi2O3, 20wt% B2O3, 10wt% SiO2, 4wt% ZnO, 3wt% Al2O3, 4wt% Na2O, and 1wt% Li2O and put them into an agate mortar. Mix the raw materials evenly and put them into a platinum crucible. After the muffle furnace is heated to 950℃, put the platinum crucible into it and keep it at that temperature for 60 minutes. After the temperature is kept, take out the platinum crucible. At this time, the glass melt in the platinum crucible is rapidly cooled to glass blocks in the air. After the glass blocks are broken, put them into the mortar and grind them. Pass them through a 300-mesh sieve to obtain glass powder.

[0060] (2)(Sr,Ca)AlSiN3:Eu 2+ The red phosphor and the glass powder from step (1) were weighed in a 1:2 ratio, and the YAG:Ce fluorescent ceramic sheet was ground to 0.4 mm. Other conditions were the same as in Example 1 to obtain the glass-based fluorescent ceramic material.

[0061] The glass-based fluorescent ceramic material of this embodiment is encapsulated with a blue light chip to form an LED device. At room temperature, with a constant current of 670mA applied, the measured performance parameters are as follows:

[0062] Luminous efficacy: 77.44 lm / W; Color rendering index: 81.6.

[0063] As can be seen, the glass-based fluorescent ceramic material in this embodiment has excellent light and color performance, which can meet the needs of high-power LED lighting.

[0064] Example 4

[0065] The preparation method of glass-based fluorescent ceramic materials is as follows:

[0066] (1) Preparation of glass powder: Take glass raw materials with 58wt% Bi2O3, 20wt% B2O3, 10wt% SiO2, 4wt% ZnO, 3wt% Al2O3, 4wt% Na2O, and 1wt% Li2O and put them into an agate mortar. Mix the raw materials evenly and put them into a platinum crucible. After the muffle furnace is heated to 950℃, put the platinum crucible into it and keep it at that temperature for 60 minutes. After the temperature is kept, take out the platinum crucible. At this time, the glass melt in the platinum crucible is rapidly cooled to glass blocks in the air. After the glass blocks are broken, put them into the mortar and grind them. Pass them through a 300-mesh sieve to obtain glass powder.

[0067] (2)(Sr,Ca)AlSiN3:Eu 2+ The red phosphor and the glass powder from step (1) were weighed in a ratio of 1:3, and other conditions were the same as in Example 1, to obtain a glass-based fluorescent ceramic material.

[0068] The glass-based fluorescent ceramic material of this embodiment is encapsulated with a blue light chip to form an LED device. At room temperature, with a constant current of 670mA applied, the measured performance parameters are as follows:

[0069] Luminous efficacy: 107.31 lm / W; Color rendering index: 71.2.

[0070] As can be seen, the glass-based fluorescent ceramic material in this embodiment has excellent light and color performance, which can meet the needs of high-power LED lighting.

[0071] Comparative Example 1

[0072] The preparation method of fluorescent glass is as follows:

[0073] (1) Preparation of glass powder: Weigh the powder raw materials according to 52mol%PbO, 33mol%B2O3, 10mol%ZnO and 5mol%SiO2, mix them and melt them at 800℃ for 3 hours to obtain glass powder.

[0074] (2) Take the glass powder from step (1) and add 5 wt% YAG:Ce phosphor and 5 wt% (Sr,Ca)AlSiN3:Eu 2+ Red phosphor powder was mixed and placed in a crucible, which was then placed directly into a resistance furnace at 600°C. After holding at this temperature for 30 minutes, the mixture was shaped and annealed at 300°C to obtain fluorescent glass.

[0075] The prepared fluorescent glass is opaque and has low hardness, making it impossible to measure its luminescence properties.

[0076] It can be seen that the addition of yellow and red phosphors in this comparative example resulted in an opaque fluorescent glass with lower hardness. Compared with Example 1, the superior performance of the glass-based fluorescent ceramic in this invention is evident.

[0077] Comparative Example 2

[0078] The preparation method of glass-based fluorescent ceramic materials is as follows:

[0079] (1) Preparation of glass powder: Take glass raw materials according to 58wt% Bi2O3, 20wt% B2O3, 10wt% SiO2, 4wt% ZnO, 3wt% Al2O3, 4wt% Na2O, and 1wt% Li2O and put them into an agate mortar. After the raw materials are mixed evenly, put them into a platinum crucible. After the muffle furnace is heated to 950℃, put them into the crucible and keep them warm for 60 minutes. After the heat preservation is completed, take them out and cool them quickly in the air. After crushing, put them into the mortar and grind them. Pass them through a 300-mesh sieve to obtain glass powder.

[0080] (2)(Sr,Ca)AlSiN3:Eu 2+The red phosphor and the glass powder from step (1) were weighed in a ratio of 9:1, and other conditions were the same as in Example 1, to obtain a glass-based fluorescent ceramic material.

[0081] Because the glass-based fluorescent ceramic material contains relatively little glass powder, the phosphor is difficult to adhere to the ceramic sheet, and it is easy to scrape the phosphor off the ceramic sheet.

[0082] Comparative Example 3

[0083] The preparation method of glass-based fluorescent ceramic materials is as follows:

[0084] (1) Preparation of glass powder: Take glass raw materials according to 58wt% Bi2O3, 20wt% B2O3, 10wt% SiO2, 4wt% ZnO, 3wt% Al2O3, 4wt% Na2O, and 1wt% Li2O and put them into an agate mortar. After the raw materials are mixed evenly, put them into a platinum crucible. After the muffle furnace is heated to 950℃, put them into the crucible and keep them warm for 60 minutes. After the heat preservation is completed, take them out and cool them quickly in the air. After crushing, put them into the mortar and grind them. Pass them through a 300-mesh sieve to obtain glass powder.

[0085] (2) K2SiF6:Mn 4+ The red phosphor and the glass powder from step (1) were weighed in a 1:1 ratio, and other conditions were the same as in Example 1, to obtain a glass-based fluorescent ceramic material.

[0086] Due to K2SiF6:Mn 4+ The red phosphor has poor thermal stability, causing it to turn black after co-sintering with glass powder at 530℃, making it impossible to measure its luminescence properties. This indicates that K2SiF6:Mn... 4+ Red fluorescent powder is not suitable for this method.

[0087] The exemplary embodiments of the present invention have been described above. However, the scope of protection of this application is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A glass-based fluorescent ceramic material, characterized in that, It includes a substrate and a fluorescent glass film, wherein the fluorescent glass film is disposed on at least one surface of the substrate; The substrate is selected from garnet-based fluorescent ceramics; The fluorescent glass film comprises at least a glass body and a fluorescent element; The garnet-based fluorescent ceramic is selected from either YAG-based fluorescent ceramic or LuAG-based fluorescent ceramic. The fluorescent element is uniformly distributed in the glass body; The fluorescent element in the fluorescent glass film contains 0.003-0.009 wt%; The thickness ratio of the substrate to the fluorescent glass film is 20:1-50:1; The glass body is selected from Bi2O3-B2O3-SiO2-Na2O-M. x O glass system, in which oxide M x In O, M is selected from at least one of Li, Zn, Al, P, Ba, and Ga, and x is selected from 1 to 3. The fluorescent element is selected from elements that exhibit red fluorescence.

2. The glass-based fluorescent ceramic material according to claim 1, characterized in that, The fluorescent glass film is prepared by mixing the glass powder with the fluorescent element and sintering it.

3. The method for preparing the glass-based fluorescent ceramic material according to claim 1 or 2, characterized in that, The preparation method includes the following steps: (1) Preparation of glass powder: glass powder is obtained by melting glass and then rapidly cooling it. (2) Mix the phosphor with the glass powder obtained in step (1) and add an organic solvent to prepare a slurry; (3) The slurry from step (2) is coated onto the substrate surface, dried, and sintered to obtain the glass-based composite fluorescent ceramic.

4. The preparation method according to claim 3, characterized in that, In step (1), the melting temperature is above 800°C; In step (1), the melting time is 30 min to 120 min.

5. The preparation method according to claim 4, characterized in that, In step (1), after melting, a heat preservation treatment is also performed. The heat preservation treatment refers to heat preservation at the melting temperature for 10 min to 60 min. In step (1), the rapid cooling process includes rapidly cooling the molten glass body at 0~100℃, followed by crushing and grinding.

6. The preparation method according to claim 3, characterized in that, In step (2), the organic solvent is selected from a mixture of alcohols and cellulose; In step (2), the mass ratio of the alcohol to cellulose is 1-30:1; In step (2), the phosphor accounts for 0.1wt%-80wt% of the total mass of the glass powder and the phosphor.

7. The preparation method according to claim 3, characterized in that, In step (3), drying is carried out at a temperature below 100°C; In step (3), the sintering conditions include: sintering temperature of 400℃-600℃ and holding time of 10-30min.

8. The application of the glass-based fluorescent ceramic material according to claim 1 or 2 in high-power LEDs.

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