Fluorescence converter and preparation method thereof

Abstract

The invention belongs to the technical field of underwater lighting, and particularly discloses a fluorescence converter and a preparation method thereof. The fluorescence converter comprises a heat conduction substrate and a metal fluorescent layer which are arranged in a stacked mode. The metal fluorescent layer contains nano-silver and fluorescent powder; the heat conduction substrate comprises a metal base material layer. Wherein the metal fluorescent layer can be obtained by uniformly mixing nano-silver paste and fluorescent powder particles, and can also be obtained by spraying the fluorescent powder particles on the surface of the nano-silver paste. According to the fluorescent converter, the metal fluorescent layer containing the nano-silver is arranged and the heat conduction substrate is introduced, so that the heat dissipation capability of the fluorescent powder can be remarkably improved, the luminous flux of the fluorescent converter is further improved, and the capability of the fluorescent converter for bearing high-power laser irradiation is improved. Meanwhile, the sintering temperature of the nano-silver is lower than that of common glass powder, so that thermal damage to the fluorescent powder in the sintering process can be reduced, the luminous efficiency of the metal fluorescent layer is improved, the service life of the metal fluorescent layer is prolonged, and the requirements for high brightness and high reliability of deep sea illumination are met.

Description

Technical Field

[0001] This invention belongs to the field of underwater lighting technology, specifically relating to a fluorescence converter and its preparation method. Background Technology

[0002] With the rapid development of marine technology, the demand for deep-sea lighting is constantly increasing in areas such as military applications, seabed oil / gas development, mineral exploration, underwater space resource utilization, and deep drilling, deep diving, and deep-netting technologies. Laser light sources have advantages such as high luminous efficiency, high brightness, energy saving, and environmental friendliness, making them suitable for deep-sea lighting. Currently, deep-sea laser light sources mainly use blue lasers to excite fluorescent conversion materials to obtain white light. Due to the small laser spot size and concentrated power density, the fluorescent converter generates extremely high amounts of heat. Traditional fluorescent converters mix phosphors with silica gel to form fluorescent silica gel, but silica gel has low thermal conductivity and poor heat resistance, making it prone to cracking and aging under laser irradiation. To improve reliability, phosphors can be mixed with glass powder and sintered at high temperatures to form fluorescent glass. However, glass has low thermal conductivity, only 0.2-2 W / (m·K). Under high-power laser excitation, the temperature of the fluorescent glass rises sharply, causing phosphor quenching and rapid saturation of luminous flux, making it difficult to meet the high-power and high-brightness lighting requirements of the deep sea. In addition, the sintering temperature of fluorescent glass films is currently relatively high, around 620°C. At high temperatures, the quantum efficiency of phosphors will drop sharply, resulting in a decrease in the luminous efficacy of the fluorescent glass film.

[0003] To improve the heat dissipation performance of fluorescent glass, a fluorescent glass paste is typically applied to the surface of a heat dissipation substrate before sintering. Since the coefficient of thermal expansion of alumina ceramic is similar to that of fluorescent glass, delamination between the two does not occur during sintering. However, due to the low thermal conductivity of alumina (only 20 W / (m·K), it can typically only withstand power densities of 10 W / mm². 2 The following describes laser irradiation. It is well known that the thermal conductivity of copper and aluminum is much higher than that of alumina ceramics, and they are also inexpensive. However, copper has a much higher coefficient of thermal expansion than fluorescent glass. During high-temperature sintering, the two materials may experience interfacial delamination due to phosphor-thermal mismatch, and the fluorescent glass film may even break and detach. Currently, some researchers are using aluminum as a heat dissipation substrate. However, to address the thermal conductivity mismatch issue, a thermal buffer layer is applied directly to the fluorescent glass film and the aluminum substrate. But this thermal buffer layer reduces heat transfer efficiency.

[0004] In summary, white laser fluorescent glass films currently face the following three problems: 1) The low thermal conductivity of the glass matrix leads to severe photothermal coupling effect in the fluorescent glass film; 2) The low thermal conductivity of the ceramic thermally conductive substrate, but due to the mismatch between the thermal expansion coefficients of glass and metal, it is impossible to use high thermal conductivity metals as thermally conductive substrates; 3) The high sintering temperature of the fluorescent glass film severely reduces the quantum efficiency of the phosphor. Summary of the Invention

[0005] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide a fluorescence converter.

[0006] The second objective of this invention is to provide a method for preparing a fluorescence converter.

[0007] The third objective of this invention is to provide a lighting device.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A first aspect of the present invention provides a fluorescence converter, comprising a thermally conductive substrate and a metal fluorescent layer stacked thereon; the metal fluorescent layer contains silver nanoparticles and phosphor; the thermally conductive substrate comprises a metal substrate layer.

[0009] The metallic phosphor layer in this invention is mainly composed of nano-silver and phosphor. Nano-silver replaces the glass matrix in existing technologies because its thermal conductivity is significantly higher than that of glass, enabling efficient heat dissipation of the phosphor, rapidly reducing its operating temperature, and effectively mitigating the photothermal coupling effect. Furthermore, the thermal conductivity of nano-silver is close to that of the metallic substrate layer, allowing for better compatibility between the two during sintering and preventing interfacial delamination. The thermal conductivity of the metallic substrate layer is also much higher than that of the ceramic substrate in existing technologies, further improving the thermal conductivity of the phosphor converter and achieving rapid heat dissipation.

[0010] In some embodiments of the present invention, the average particle size of the nanosilver is 10-50 nm; in some embodiments of the present invention, the average particle size of the nanosilver is any value of 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, or a range formed by any two of them.

[0011] In some embodiments of the present invention, the thickness of the metal substrate layer is 0.1 to 10 mm; in some embodiments of the present invention, the thickness of the metal substrate layer is any value of 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or a range formed by any two of these values.

[0012] In some embodiments of the present invention, the thickness of the metallic fluorescent layer is 10~400 μm; in some embodiments of the present invention, the thickness of the metallic fluorescent layer is 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm. The range of values ​​formed by any one of the following: m, 130μm, 135μm, 140μm, 145μm, 150μm, 155μm, 160μm, 165μm, 170μm, 175μm, 180μm, 185μm, 190μm, 195μm, 200μm, 220μm, 240μm, 250μm, 260μm, 280μm, 300μm, 320μm, 340μm, 350μm, 360μm, 380μm, 400μm, or any combination thereof.

[0013] In some embodiments of the present invention, the mass ratio of the nano-silver to the phosphor is (0.2~5):1; in some embodiments of the present invention, the mass ratio of the nano-silver to the phosphor is any value or a range formed by any two of the following: 0.2:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1, 5:1.

[0014] In some embodiments of the present invention, the phosphor is selected from Y3Al5O 12 :Ce 3+ CaAlSiN3:Eu 2+ Lu3Al5O 12 :Ce 3+ At least one of the following; wherein, Y3Al5O 12 :Ce 3+ It is a yellow YAG phosphor; CaAlSiN3:Eu 2+ It is a red CASN phosphor, Lu3Al5O 12 :Ce 3+ It is a green LuAG phosphor.

[0015] In some embodiments of the present invention, the material of the metal substrate layer is selected from at least one of copper and aluminum.

[0016] In some embodiments of the present invention, the thermally conductive substrate further includes a gold wetting layer disposed on the surface of the metal substrate layer; the gold wetting layer is located between the metal substrate layer and the metal phosphor layer. Disposing of a gold wetting layer on the metal substrate layer can prevent oxidation of the metal substrate layer, thereby affecting the laser saturation threshold and luminous flux of the phosphor converter.

[0017] In some embodiments of the present invention, the thickness of the gold wetting layer is 25~500 μm; in some embodiments of the present invention, the thickness of the gold wetting layer is 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm. The range of values ​​formed by any one of the following: 150μm, 155μm, 160μm, 165μm, 170μm, 175μm, 180μm, 185μm, 190μm, 195μm, 200μm, 220μm, 240μm, 250μm, 260μm, 280μm, 300μm, 320μm, 340μm, 350μm, 360μm, 380μm, 400μm, 420μm, 440μm, 450μm, 460μm, 480μm, 500μm.

[0018] In some embodiments of the present invention, the material of the gold wetting layer includes Au; in some embodiments of the present invention, the material of the gold wetting layer is Au.

[0019] In some embodiments of the present invention, the metallic fluorescent layer comprises a silver nanolayer and phosphor particles; the phosphor particles are dispersed inside and / or on the surface of the silver nanolayer.

[0020] The second aspect of the present invention provides a method for preparing the fluorescence converter described in the first aspect of the present invention, wherein the preparation method is method one or method two; The first method includes the following steps: A metallic fluorescent paste is prepared by mixing materials including nano-silver and phosphor. The metallic phosphor paste is coated onto the surface of the thermally conductive substrate and then sintered to obtain the phosphor converter. The second method includes the following steps: A paste containing silver nanoparticles is coated onto the surface of the thermally conductive substrate to form a silver nanoparticle layer; Phosphor particles are sprayed onto the surface of the nano-silver layer, pressure is applied to embed the phosphor particles into the nano-silver layer, and sintering is performed to obtain the fluorescence converter.

[0021] In this invention, nano-silver is used as a raw material. Nano-silver has a low sintering temperature of only 250~400℃, which is much lower than the 620℃ of glass. This can reduce the thermal damage to the phosphor during sintering, thereby improving the quantum efficiency of the phosphor.

[0022] In some embodiments of the present invention, the step of coating the metal phosphor paste on the surface of the thermally conductive substrate specifically involves coating the metal phosphor paste onto the surface of the metal substrate layer or the gold wetting layer in the thermally conductive substrate, and then drying it to form a film of the metal phosphor paste on the surface of the thermally conductive substrate.

[0023] In some embodiments of the present invention, the coating is performed by scraping.

[0024] In some embodiments of the present invention, the drying temperature is 70~120°C; in some embodiments of the present invention, the drying temperature is any value or a range formed by any two of 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, and 120°C.

[0025] In some embodiments of the present invention, the drying time is 20 to 60 minutes; in some embodiments of the present invention, the drying time is any value of 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, or a range formed by any two of these values.

[0026] In some embodiments of the present invention, the sintering temperature is 250~400℃; in some embodiments of the present invention, the sintering temperature is any value or a range formed by any two of the following: 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, 295℃, 300℃, 305℃, 310℃, 315℃, 320℃, 325℃, 330℃, 335℃, 340℃, 345℃, 350℃, 355℃, 360℃, 365℃, 370℃, 375℃, 380℃, 385℃, 390℃, 395℃, and 400℃.

[0027] In some embodiments of the present invention, the sintering time is 20 to 50 minutes; in some embodiments of the present invention, the sintering time is any value or a range formed by any two of the following: 20 minutes, 22 minutes, 24 minutes, 25 minutes, 26 minutes, 28 minutes, 30 minutes, 32 minutes, 34 minutes, 35 minutes, 36 minutes, 38 minutes, 40 minutes, 42 minutes, 44 minutes, 45 minutes, 46 minutes, 48 ​​minutes, and 50 minutes.

[0028] In some embodiments of the present invention, the metallic fluorescent paste contains nano-silver, fluorescent powder, binder and solvent.

[0029] In some embodiments of the present invention, the metallic fluorescent paste is obtained by mixing phosphor, nano-silver, ethyl cellulose, and terpineol. In some embodiments of the present invention, the metallic fluorescent paste is prepared by a method comprising the following steps: first, heating ethyl cellulose and terpineol to 80-100°C and mixing them, then mixing them with phosphor and nano-silver.

[0030] In some embodiments of the present invention, the mass ratio of phosphor to ethyl cellulose is 1:(0.01~0.06); in some embodiments of the present invention, the mass ratio of phosphor to ethyl cellulose is any value of 1:0.01, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06 or a range formed by any two of them.

[0031] In some embodiments of the present invention, the mass ratio of phosphor to terpineol is 1:(0.2~0.8); in some embodiments of the present invention, the mass ratio of phosphor to terpineol is any value of 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8 or any range formed by both.

[0032] In some embodiments of the present invention, the mass ratio of ethyl cellulose to terpineol is 1:(18~22); in some embodiments of the present invention, any value of 1:18, 1:19, 1:20, 1:21, 1:22 or a range formed by any two of them.

[0033] A third aspect of the present invention provides a lighting device including the fluorescence converter described in the first aspect of the present invention.

[0034] The beneficial effects of the present invention are as follows: By setting a metal fluorescent layer containing nano-silver and introducing a thermally conductive substrate, the fluorescent converter of the present invention can significantly improve the heat dissipation capacity of the phosphor, thereby increasing the luminous flux of the fluorescent converter and improving its ability to withstand high-power laser irradiation, thus meeting the high brightness requirements of deep-sea lighting.

[0035] The method for preparing the fluorescence converter in this invention uses silver paste as the preparation material, which enables sintering at a low temperature of 250~400℃, reducing thermal damage to the phosphor and thus improving the laser saturation threshold and luminous flux of the fluorescence converter containing it. Detailed Implementation

[0036] The following examples provide a more detailed description of the specific implementation of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are methods that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0037] In some embodiments of the present invention, a fluorescence converter is provided, comprising a thermally conductive substrate and a metal fluorescent layer stacked thereon; the metal fluorescent layer contains silver nanoparticles and phosphor; the thermally conductive substrate comprises a metal substrate layer.

[0038] The metallic phosphor layer in this invention is mainly composed of nano-silver and phosphor. Nano-silver replaces the glass matrix in existing technologies because its thermal conductivity is significantly higher than that of glass, enabling efficient heat dissipation of the phosphor, rapidly reducing its operating temperature, and effectively mitigating the photothermal coupling effect. Furthermore, the thermal conductivity of nano-silver is close to that of the metallic substrate layer, allowing for better compatibility between the two during sintering and preventing interfacial delamination. The thermal conductivity of the metallic substrate layer is also much higher than that of the ceramic substrate in existing technologies, further improving the thermal conductivity of the phosphor converter and achieving rapid heat dissipation.

[0039] In some embodiments of the present invention, the average particle size of the silver nanoparticles is 10-50 nm; in some embodiments of the present invention, the average particle size of the silver nanoparticles is any value of 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, or a range formed by any two of them.

[0040] In some embodiments of the present invention, the thickness of the metal substrate layer is 0.1~10mm; in some embodiments of the present invention, the thickness of the metal substrate layer is any value of 0.1mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or a range formed by any two of them.

[0041] In some embodiments of the present invention, the thickness of the metallic fluorescent layer is 10~400 μm; in some embodiments of the present invention, the thickness of the metallic fluorescent layer is 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm. The range of values ​​formed by any combination of 130μm, 135μm, 140μm, 145μm, 150μm, 155μm, 160μm, 165μm, 170μm, 175μm, 180μm, 185μm, 190μm, 195μm, 200μm, 220μm, 240μm, 250μm, 260μm, 280μm, 300μm, 320μm, 340μm, 350μm, 360μm, 380μm, and 400μm.

[0042] In some embodiments of the present invention, the mass ratio of the nano-silver to the phosphor is (0.2~5):1; in some embodiments of the present invention, the mass ratio of the nano-silver to the phosphor is any value or a range formed by any two of the following: 0.2:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1, 5:1.

[0043] In some embodiments of the present invention, the phosphor is selected from Y3Al5O 12 :Ce 3+ CaAlSiN3:Eu 2+ Lu3Al5O 12 :Ce 3+ At least one of the following; wherein, Y3Al5O 12 :Ce 3+ It is a yellow YAG phosphor; CaAlSiN3:Eu 2+ It is a red CASN phosphor, Lu3Al5O 12 :Ce 3+ It is a green LuAG phosphor.

[0044] In some embodiments of the present invention, the material of the metal substrate layer is selected from at least one of copper and aluminum.

[0045] In some embodiments of the present invention, the thermally conductive substrate further includes a gold wetting layer disposed on the surface of the metal substrate layer; the gold wetting layer is located between the metal substrate layer and the metal phosphor layer. Disposing of a gold wetting layer on the metal substrate layer can prevent oxidation of the metal substrate layer, thereby affecting the laser saturation threshold and luminous flux of the phosphor converter.

[0046] In some embodiments of the present invention, the thickness of the gold wetting layer is 25~500 μm; in some embodiments of the present invention, the thickness of the gold wetting layer is 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, 1 The range of values ​​formed by any one of the following: 50μm, 155μm, 160μm, 165μm, 170μm, 175μm, 180μm, 185μm, 190μm, 195μm, 200μm, 220μm, 240μm, 250μm, 260μm, 280μm, 300μm, 320μm, 340μm, 350μm, 360μm, 380μm, 400μm, 420μm, 440μm, 450μm, 460μm, 480μm, 500μm.

[0047] In some embodiments of the present invention, the material of the gold wetting layer includes Au; in some embodiments of the present invention, the material of the gold wetting layer is Au.

[0048] In some embodiments of the present invention, the metallic fluorescent layer comprises a silver nanolayer and phosphor particles; the phosphor particles are dispersed inside and / or on the surface of the silver nanolayer.

[0049] In some embodiments of the present invention, a method for preparing a fluorescence converter is provided, comprising the following steps: A metallic fluorescent paste is prepared by mixing materials including nano-silver and phosphor. The metallic phosphor paste is coated onto the surface of the thermally conductive substrate and then sintered to obtain the phosphor converter. In some embodiments of the present invention, a method for preparing a fluorescence converter is provided, comprising the following steps: A paste containing silver nanoparticles is coated onto the surface of the thermally conductive substrate to form a silver nanoparticle layer; Phosphor particles are sprayed onto the surface of the nano-silver layer, pressure is applied to embed the phosphor particles into the nano-silver layer, and sintering is performed to obtain the fluorescence converter.

[0050] In this invention, nano-silver is used as a raw material. Nano-silver has a low sintering temperature of only 250~400℃, which is much lower than the 620℃ of glass. This can reduce the thermal damage to the phosphor during sintering, thereby improving the quantum efficiency of the phosphor.

[0051] In some embodiments of the present invention, the step of coating the metal phosphor paste on the surface of the thermally conductive substrate specifically involves coating the metal phosphor paste onto the surface of the metal substrate layer or the gold wetting layer in the thermally conductive substrate, and then drying it to form a film of the metal phosphor paste on the surface of the thermally conductive substrate.

[0052] In some embodiments of the present invention, the coating is performed by scraping.

[0053] In some embodiments of the present invention, the drying temperature is 70~120℃; in some embodiments of the present invention, the drying temperature is any value or a range formed by any two of 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, and 120℃.

[0054] In some embodiments of the present invention, the drying time is 20 to 60 minutes; in some embodiments of the present invention, the drying time is any value of 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, or a range formed by any two of them.

[0055] In some embodiments of the present invention, the sintering temperature is 250~400℃; in some embodiments of the present invention, the sintering temperature is any value or a range formed by any two of the following: 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, 295℃, 300℃, 305℃, 310℃, 315℃, 320℃, 325℃, 330℃, 335℃, 340℃, 345℃, 350℃, 355℃, 360℃, 365℃, 370℃, 375℃, 380℃, 385℃, 390℃, 395℃, and 400℃.

[0056] In some embodiments of the present invention, the sintering time is 20-50 min; in some embodiments of the present invention, the sintering time is any value or a range formed by any two of the following: 20 min, 22 min, 24 min, 25 min, 26 min, 28 min, 30 min, 32 min, 34 min, 35 min, 36 min, 38 min, 40 min, 42 min, 44 min, 45 min, 46 min, 48 min, and 50 min.

[0057] In some embodiments of the present invention, the metallic fluorescent paste contains nano-silver, fluorescent powder, binder and solvent.

[0058] In some embodiments of the present invention, the metallic fluorescent paste is obtained by mixing fluorescent powder, nano silver, ethyl cellulose, and terpineol.

[0059] In some embodiments of the present invention, the mass ratio of phosphor to ethyl cellulose is 1:(0.01~0.06); in some embodiments of the present invention, the mass ratio of phosphor to ethyl cellulose is any value of 1:0.01, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06 or a range formed by any two of them.

[0060] In some embodiments of the present invention, the mass ratio of phosphor to terpineol is 1:(0.2~0.8); in some embodiments of the present invention, the mass ratio of phosphor to terpineol is any value of 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8 or a range formed by any two of these values.

[0061] The specific implementation of the present invention will be further described in detail below with reference to specific embodiments: Example 1 This example provides a fluorescence converter, including a copper substrate, a gold wetting layer and a metallic phosphor layer stacked sequentially. The copper substrate has a thickness of 1mm and a size of 15mm × 15mm. The thickness of the gold wetting layer is 25 μm; The thickness of the metallic fluorescent layer is 100 μm; the metallic fluorescent layer contains silver nanoparticles and phosphor (i.e., yellow YAG phosphor), and the mass ratio of silver nanoparticle paste to phosphor is 1:1; the average particle size of the silver nanoparticles is 25 nm.

[0062] This example provides a method for preparing a fluorescence converter, including the following steps: To prevent oxidation of the copper substrate, a gold wetting layer (25 μm thick) was deposited on the surface of the copper substrate. A fluorescent metal paste was formed by mixing 0.89 g of silver paste (90% solids content), 0.8 g of yellow YAG phosphor, 0.017 g of ethyl cellulose, and 0.35 g of terpineol. This paste was then coated onto the gold wetting layer using a doctor blade to form a 120 μm thick fluorescent metal paste film. It was subsequently dried at 90 °C for 20 min. Finally, the dried metal paste film was sintered at 250 °C for 30 min and cooled in the furnace to obtain the phosphor converter in this example.

[0063] White light is generated by a laser that excites a fluorescence converter, and the luminous flux of this white light is measured using an integrating sphere. During the test, the laser power is continuously increased, and the luminous flux of the white light obtained by exciting the fluorescence converter at different powers is recorded. As the laser power increases, its luminous flux continuously rises. However, once the laser power exceeds a certain value, its luminous flux continuously decreases. The laser power corresponding to the highest luminous flux is called the saturation threshold.

[0064] Tests showed that the laser saturation threshold (i.e., the maximum laser power density that the fluorescence converter in this example can withstand) is 50 W / mm². 2 The corresponding luminous flux is 8698 lm.

[0065] Example 2 This example provides a fluorescence converter, including a copper substrate and a metallic phosphor layer stacked sequentially. The copper substrate has a thickness of 2mm and a size of 20×20mm. The thickness of the metallic fluorescent layer is 150 μm; the metallic fluorescent layer contains silver nanoparticles and phosphor, the average particle size of the silver nanoparticles is 35 nm, and the mass ratio of silver nanoparticles to phosphor in the metallic fluorescent layer is 2:1.

[0066] This example provides a method for preparing a fluorescence converter, including the following steps: A fluorescent metal paste was prepared by mixing 1.33 g of silver paste (90% solids content), 0.6 g of phosphor (0.5 g of yellow YAG phosphor and 0.1 g of red CASN phosphor), 0.02 g of ethyl cellulose, and 0.4 g of terpineol. This paste was then coated onto a copper substrate using a doctor blade to form a 180 μm thick film. The film was subsequently dried at 90 °C for 20 min. Finally, the dried metal paste film was sintered at 300 °C for 30 min and then cooled in the furnace to obtain the phosphor converter in this example.

[0067] The laser saturation threshold of the fluorescence converter in this example was tested to be 46 W / mm². 2 The corresponding luminous flux is 7546 lm.

[0068] Example 3 This example provides a fluorescence converter, including an aluminum substrate and a metallic phosphor layer stacked sequentially. The aluminum substrate has a thickness of 1.5 mm and a size of 10×10 mm. The thickness of the metallic fluorescent layer is 200 μm; the metallic fluorescent layer contains silver nanoparticles and phosphor, with a mass ratio of silver nanoparticles to phosphor of 0.5:1, and the average particle size of the silver nanoparticles is 50 nm.

[0069] This example provides a method for preparing a fluorescence converter, including the following steps: A fluorescent metal paste was prepared by mixing 0.45 g of silver paste (90% solids content), 0.8 g of phosphor (0.4 g of yellow YAG phosphor and 0.4 g of green LuAG phosphor), 0.014 g of ethyl cellulose, and 0.30 g of terpineol. This paste was then applied to an aluminum substrate using a doctor blade to form a 230 μm thick film. The film was subsequently dried at 90 °C for 20 min. Finally, the dried metal paste film was sintered at 350 °C for 30 min and then cooled in the furnace to obtain the fluorescence converter described in this example.

[0070] Tests showed that the laser saturation threshold of the fluorescence converter in this example is 40 W / mm². 2 The corresponding luminous flux is 6578 lm.

[0071] In summary, the laser saturation threshold of the fluorescence converters prepared in Examples 1-3 of this invention is 35-60 W / mm². 2 The luminous flux is 6000~9000lm, and the laser saturation threshold and luminous flux are significantly higher than those of the scheme using phosphor and glass powder. Therefore, the present invention has a better luminous effect and can be used for underwater laser illumination.

[0072] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A fluorescence converter, characterized in that: It includes a thermally conductive substrate and a metallic fluorescent layer stacked together; the metallic fluorescent layer contains silver nanoparticles and phosphor. The thermally conductive substrate includes a metal substrate layer.

2. The fluorescence converter according to claim 1, characterized in that: The average particle size of the silver nanoparticles is 10~50 nm; And / or, the thickness of the metallic phosphor layer is 10~400μm.

3. The fluorescence converter according to claim 1, characterized in that: The phosphor is selected from Y3Al5O 12 :Ce 3+ CaAlSiN3:Eu 2+ Lu3Al5O 12 :Ce 3+ At least one of them; And / or, the material of the metal substrate layer is selected from at least one of copper and aluminum.

4. The fluorescence converter according to claim 1, characterized in that: The thermally conductive substrate further includes a gold wetting layer disposed on the surface of the metal substrate layer; the gold wetting layer is located between the metal substrate layer and the metal phosphor layer.

5. The fluorescence converter according to claim 4, characterized in that: The thickness of the gold wetting layer is 25~500μm; And / or, the material of the gold wetting layer includes Au.

6. The fluorescence converter according to claim 1, characterized in that: The mass ratio of the nano-silver to the phosphor is (0.2~5):

1.

7. The fluorescence converter according to claim 1, characterized in that: The metallic fluorescent layer comprises a silver nanoparticle layer and phosphor particles; the phosphor particles are dispersed inside and / or on the surface of the silver nanoparticle layer.

8. The method for preparing the fluorescence converter according to any one of claims 1 to 7, characterized in that: The preparation method is either Method 1 or Method 2; The first method includes the following steps: A metallic fluorescent paste is prepared by mixing materials including nano-silver and phosphor. The metallic phosphor paste is coated onto the surface of the thermally conductive substrate and then sintered to obtain the phosphor converter. The second method includes the following steps: A paste containing silver nanoparticles is coated onto the surface of the thermally conductive substrate to form a silver nanoparticle layer; Phosphor particles are sprayed onto the surface of the nano-silver layer, pressure is applied to embed the phosphor particles into the nano-silver layer, and sintering is performed to obtain the fluorescence converter.

9. The method for preparing a fluorescence converter according to claim 8, characterized in that: The sintering temperature is 250~400℃; and / or the sintering time is 20~50min; And / or, the metallic fluorescent paste contains nano-silver, fluorescent powder, binder and solvent.

10. A lighting device, characterized in that: Includes the fluorescence converter according to any one of claims 1 to 7.