Manufacturing method of metal substrate fluorescence wavelength converter

Abstract

The invention discloses a manufacturing method of a metal substrate fluorescence wavelength converter, which is characterized by sequentially comprising the following steps of: preparing a metal substrate, plating a dielectric film on one surface of the metal substrate, preparing fluorescent film slurry, forming a fluorescent film on the dielectric film, and sintering the fluorescent film at high temperature. The fluorescence wavelength converter manufactured by the invention has the advantages of high conversion efficiency, stable optical performance, good reliability and the like, and can be used in the fields of laser illumination, display and the like.

Description

Technical Field

[0001] The present invention relates to a manufacturing method of a metal substrate fluorescence wavelength converter, which is used in fields such as laser lighting and display. The metal substrate fluorescence wavelength converter of the present invention has the advantages of high conversion efficiency, stable optical performance, good reliability, etc. Background Art

[0002] Light sources based on laser remote excitation fluorescence are being increasingly widely used in many fields such as lighting, display, and detection due to their extremely high light energy density, electro-optical conversion efficiency, and excellent reliability, etc. This technology is based on the following principle, that is, a single-wavelength high-energy density beam generated by a laser diode is used to irradiate and pass through a fluorescence wavelength converter to convert the incident monochromatic light into white light, so as to meet the requirements of being a lighting source. Obviously, the fluorescence wavelength converter plays an important role in such light source technologies, and its conversion efficiency and other performances directly affect the efficiency, reliability, and service life of the light source.

[0003] Heat will be generated during the working process of the fluorescence wavelength converter. Especially in the case of using a high-power laser diode as the excitation source, the incident beam size is very small, and the energy density is therefore very large. For example, the beam diameter can be as small as 0.2 mm, while the optical power of the laser beam can be as high as 5 W. In this case, the energy density of the incident light on the surface of the fluorescence wavelength converter can be as high as 160 W / mm2. Since the efficiency of fluorescence wavelength conversion is usually only about 80%, about 20% of the incident light energy needs to be converted into heat, which needs to be timely exported and dissipated through a heat dissipation device. Otherwise, it will greatly reduce the efficiency of the fluorescence wavelength converter and even cause permanent damage to it.

[0004] In the existing technologies, generally, the fluorescence wavelength converter is connected to a metal substrate with high thermal conductivity by means of organic glue or welding, so that the heat generated during the working process of the fluorescence wavelength converter is dissipated to the environment through the metal substrate and the radiator. The scheme of using organic glue connection is simple, but due to the poor thermal conductivity of the glue and its inability to withstand relatively high temperatures, it is very easy to fail when used in a high-temperature environment for a long time; while the welding scheme can solve the problems existing in the glue scheme, but its process is complex, the processing cost is expensive, and the heat generated during the welding process may also damage the performance of the fluorescence wavelength converter.

[0005] The present invention will propose a new scheme to solve the above problems. Summary of the Invention

[0006] Adopting high-temperature sintering technology to directly connect the fluorescent wavelength converter and the metal substrate can eliminate the thermal resistance between them, improve their thermal conductivity, enhance their reliability, and increase the irradiance power they can withstand. This invention patent will propose a manufacturing method for a metal substrate fluorescent wavelength converter, which directly connects the fluorescent wavelength converter and the metal substrate to achieve efficient, stable, and reliable wavelength conversion.

[0007] A manufacturing method for a metal substrate fluorescent wavelength converter of the present invention, its technological process includes: first preparing a metal substrate, then depositing a dielectric film on the side with higher reflectivity of the metal substrate, then forming a fluorescent film on the dielectric film, and finally sintering the fluorescent film at high temperature.

[0008] Further, the above-mentioned metal substrate is a metal material with high reflectivity, its thickness is between 0.3 mm and 2 mm, and its surface roughness is less than 100 nm, and it is one or a combination of more than one of the following materials: copper and copper alloys, aluminum and aluminum alloys, silver and silver alloys.

[0009] Further, the above-mentioned dielectric film is composed of one or more of the following materials: SiO2, TiO2, Ta2O5, Al2O3, ZnO2, SnO2, ZrO2, AlN, TiN, its film thickness is between 10 nm and 1000 nm, and its preparation method is one or several of the following methods used together: ordinary chemical vapor deposition (CVD), atomic layer deposition (ALD), magnetron sputtering, electron beam evaporation, thermal evaporation.

[0010] Further, the above-mentioned fluorescent film is composed of phosphor and inorganic additives, and the ratio of phosphor to additives is between 30:1 and 15:1. Among them, the phosphor is one or a combination of more than one of the following materials: (Y,Tb)2Al5O 12 :Ce 3+ , (Sr,Ba,Ca)2Si5N8:Eu 2+ , CaAlSiN3:Eu 2+ , BaMgAl 10 O 17 :Eu 2+ , BaMgAl 10 O 17 :Eu 2+ ,Mn 2+ , Ca-alpha-SiAlON:Eu 2+ , Beta-SiAlON:Eu 2+ , (Ca,Sr,Ba)2P2O7:Eu 2+ , (Ca,Sr,Ba)2P2O7:Eu 2+ ,Mn 2+, (Ca, Sr, Ba)5(PO4)3Cl:Eu 2+ , Lu2SiO5:Ce 3+ , (Ca, Sr, Ba)3SiO5:Eu 2+ , (Ca, Sr, Ba)2SiO4:Eu 2+ , Zn2SiO4:Mn 2+ , BaAl 12 O 19 :Mn 2+ , BaMgAl 14 O 23 :Mn 2+ , SrAl 12 O 19 :Mn 2+ , CaAl 12 O 19 :Mn 2+ , YBO3:Tb 3+ , LuBO3:Tb 3+ , Y2O3:Eu 3+ , Y2SiO5:Eu 3+ , Y3Al5O 12 :Eu 3+ , YBO3:Eu 3+ , Y 0.65 Gd 0.35 BO3:Eu 3+ , GdBO3:Eu 3+ , YVO4:Eu 3+ 。

[0012] Furthermore, the additive is one or a combination of more than one of the following materials: Al2O3, P2O5, B2O3, Na2O.

[0012] Furthermore, the process conditions for sintering the above fluorescent film at high temperature are: normal pressure (one atmosphere), the sintering atmosphere is air, nitrogen or argon, the sintering temperature is between 300°C and 600°C, and the holding time is 10 - 100 minutes.

[0013] The present invention has the following advantages:

[0014] (1) No organic materials are used during the manufacturing process, so there is no volatilization of organic substances during sintering, making the microstructure of the prepared fluorescent film controllable; (2) Sintering is carried out under normal pressure without the need for special atmosphere protection, and the process is relatively simple and controllable; (3) Direct bonding of the fluorescent film and the metal substrate can improve the overall conversion efficiency, stability and reliability of the fluorescence wavelength converter. Description of the Drawings

[0015] Figure 1It is a schematic structural diagram of a metal substrate fluorescence wavelength converter.

[0016] Figure 2 It is a schematic structural diagram of a fluorescent film slurry.

[0017] Figure 3 It is a process flow chart of a manufacturing method of a metal substrate fluorescence wavelength converter.

[0018] Figure 4 It is an emission spectrum diagram of YAG-Ce based phosphor.

[0019] Figure 5 It is a schematic structural diagram of a white laser light source.

[0020] Figure 6 It is the photoluminescence spectrum of the YAG-Ce based fluorescence wavelength converter sintered at 400 °C and a blue laser diode light source.

[0021] Figure 7 It is the photoluminescence spectrum of the YAG-Ce based fluorescence wavelength converter sintered at 500 °C and a blue laser diode light source. Detailed implementation manners

[0022] Figure 1 It is a schematic structural diagram of the metal substrate fluorescence wavelength converter of the present invention. As Figure 1 shown, one side of the metal substrate (101) serves as the carrier of the fluorescent film (103), and the other side serves as the contact surface between the fluorescence wavelength converter and the radiator. There is also a dielectric film (102) between the metal substrate (101) and the fluorescent film (103), and its functions are in two aspects: one is to increase the reflectivity of the contact surface between the metal substrate (101) and the fluorescent film (103), so as to ensure that as much light as possible converted by the fluorescent film is transmitted out from the other side of the fluorescent film (103), rather than being absorbed by the metal substrate (103); another function is to promote the formation of the combination between the fluorescent film (103) and the metal substrate (101) during the high-temperature sintering process.

[0023] The selection of the metal substrate (101) needs to meet the following several principles:

[0024] (1) Good thermal conductivity. Because one of the main functions of the metal substrate (101) is to transfer the heat generated by the fluorescent film during operation to the radiator or the environment as soon as possible, so under the premise of meeting other conditions, the higher its thermal conductivity, the better.

[0025] (2) Good heat resistance. The metal substrate (101) receives the heat dissipated by the fluorescent film during the operation of the fluorescence wavelength converter and is itself heated, so it needs to have a certain heat resistance, that is, to maintain the shape of the structure unchanged within the temperature range of the working environment.

[0026] (3) Good surface flatness. One side of the metal substrate (101) is to be combined with the radiator. Therefore, the flatness of this side can ensure a tight combination with the radiator surface, reduce the interface thermal resistance, and ensure the heat dissipation speed. The other side of the metal substrate (101) bears the fluorescent film and needs to reflect as much white light generated by the fluorescent film (103) during operation back to the fluorescent film and output it through the fluorescent film again. Therefore, this side of the metal substrate (101) not only needs to be flat but also has excellent reflectivity in the visible light band.

[0027] (4) Appropriate thickness. The metal substrate (101) needs to have a certain strength, which can be ensured by adjusting its thickness after the material selection is determined.

[0028] Considering the above points comprehensively, the material of the metal substrate (101) can be selected from aluminum and its alloys or copper and its alloys. Such materials not only meet the above basic requirements but also have the advantages of good processing performance and low cost. Regarding the surface flatness of the metal substrate (101), the inventor found in the experiment that the surface roughness should be less than 100 nm. Regarding the thickness of the metal substrate (101), the inventor found in the experiment that according to the design requirements, it is preferably between 0.2 mm and 20 mm.

[0029] As described above, Figure 1 The intermediate dielectric film (102) not only needs to ensure excellent reflectivity of the metal substrate (101) in the visible light band together with the metal substrate (101), but also needs to promote the formation of a tight combination between the fluorescent film (103) and the metal substrate (101) during the sintering process. Therefore, it also needs to meet the following basic requirements: (1) The coefficient of thermal expansion has a good match with the metal substrate (101) and the fluorescent film (103); (2) It has a good interfacial bonding force (adhesive force) with the metal substrate (101) and the fluorescent film (103); (3) It does not reduce the reflectivity of the metal substrate (101) at least; (4) The thickness is as thin as possible to reduce the thermal resistance; (5) The film-making process is simple and controllable. Considering the above comprehensively, the present invention proposes that the dielectric film (102) is composed of a combination of thin films of one or more of the following materials: SiO2, TiO2, Ta2O5, Al2O3, ZnO2, SnO2, ZrO2, AlN, TiN. The thickness of the dielectric film (102) is between 10 nm and 1000 nm. The film-making technology can be one or a combination of several technologies such as ordinary chemical vapor deposition (CVD), atomic layer deposition (ALD), magnetron sputtering, electron beam evaporation, thermal evaporation, etc.

[0030] The fluorescent film (103) is the key to the wavelength converter for wavelength conversion, and it needs to meet the following conditions: (1) excellent fluorescent wavelength conversion efficiency; (2) good thermal conductivity; (3) good heat resistance; (4) certain mechanical strength; (5) good interfacial adhesion with the metal substrate (101) and the dielectric film (102). To meet these conditions, the present invention proposes to first configure a slurry from a fluorescent material (powder), an additive, and a liquid (deionized water), and then use a coating printing or spraying technique to uniformly prepare the slurry on the dielectric film (102), and finally sinter it at a high temperature to form a shape.

[0031] The composition of the fluorescent film slurry is as Figure 2 shown. The fluorescent film slurry includes the following parts: phosphor powder (201), additive (202), and deionized water (203). Here, the role of the phosphor powder (201) is to absorb the incident light and convert the incident light into light of different wavelength bands; the role of the additive (202) is mainly to ensure the appropriate viscosity and fluidity of the slurry, and at the same time help the fluorescent film to have a certain porosity inside after sintering and forming, and have high heat resistance. The deionized water (203) in the slurry is also for adjusting the viscosity and fluidity of the slurry to meet the process requirements of slurry film formation.

[0032] Considering the above requirements for the fluorescent film and the slurry required for its preparation, the present invention proposes to use one or a combination of the following materials as the additive (202): Al2O3, P2O5, B2O3, Na2O.

[0033] The phosphor powder (201) can be selected according to the actual output requirements of the fluorescent wavelength converter, and a combination of one or several of green, yellow, red, orange, etc. can be selected. Further, one or several of the following fluorescent materials can be selected and combined in different proportions: (Y,Tb)2Al5O 12 :Ce 3+ , (Sr,Ba,Ca)2Si5N8:Eu 2+ , CaAlSiN3:Eu 2+ , BaMgAl 10 O 17 :Eu 2 + , BaMgAl 10 O 17 :Eu 2+ ,Mn 2+ , Ca-alpha-SiAlON:Eu 2+ , Beta-SiAlON:Eu 2+ , (Ca,Sr,Ba)2P2O7:Eu 2+ , (Ca,Sr,Ba)2P2O7:Eu 2+ ,Mn2+ , (Ca,Sr,Ba)5(PO4)3Cl:Eu 2+ , Lu2SiO5:Ce 3+ , (Ca,Sr,Ba)3SiO5:Eu 2 + , (Ca,Sr,Ba)2SiO4:Eu 2+ , Zn2SiO4:Mn 2+ , BaAl 12 O 19 :Mn 2+ , BaMgAl 14 O 23 :Mn 2+ , SrAl 12 O 19 :Mn 2+ , CaAl 12 O 19 :Mn 2+ , YBO3:Tb 3+ , LuBO3:Tb 3+ , Y2O3:Eu 3+ , Y2SiO5:Eu 3+ , Y3Al5O 12 :Eu 3+ , YBO3:Eu 3+ , Y 0.65 Gd 0.35 BO3:Eu 3+ , GdBO3:Eu 3+ , YVO4:Eu 3+ 。

[0034] Another important parameter of the fluorescent film slurry is the ratio of the phosphor (201), the additive (202), and the deionized water (203). In the present invention, the ratio between the phosphor (201) and the additive (202) is from 30:1 to 15:1, and the ratio between the additive (202) and the deionized water (203) is from 1:3 to 1:5.

[0035] The manufacturing process flow of the metal substrate fluorescent converter of the present invention can be schematically described by Figure 3 as Figure 3As shown in the figure, first, prepare the metal substrate (101) according to the above requirements. Then, form a dielectric film (102) on the high-reflectivity side of the metal substrate (101). Prepare the slurry of the fluorescent film, and then evenly coat or spray the fluorescent film slurry on the dielectric film (102). After air drying, put it into a high-temperature sintering furnace for sintering. The high-temperature sintering process can be carried out in atmospheric air or a protective gas such as nitrogen or argon. The sintering temperature is controlled below the temperature at which the metal substrate (101) undergoes thermal deformation, but it is necessary to ensure that the sintered fluorescent film has sufficient mechanical strength and forms a tight bond with the metal substrate and has excellent adhesion. The sintering temperature proposed by the present invention is between 300°C and 600°C, and it is held at this temperature for 10 - 100 minutes.

[0036] The following are some specific embodiments to further describe the technical method of the present invention, but the present invention is not limited to these embodiments.

[0037] Example 1: Manufacturing an aluminum substrate fluorescent wavelength converter by high-temperature sintering at 400°C

[0038] According to Figure 3 the process flow chart shown, first, in order to ensure that the fluorescent wavelength converter has sufficient reflectivity and flatness, select 0.3 mm mirror aluminum as the metal substrate, and its reflectivity in the wavelength band of 400 - 700 nm is above 95%. In order to improve the bonding effect between the fluorescent film and the metal substrate and further improve the reflectivity of the aluminum substrate surface, first deposit a dielectric film on the aluminum substrate. In this embodiment, SiO2 / Ta2O5 is selected as the dielectric film, and it is deposited on the aluminum substrate surface by electron beam evaporation technology.

[0039] In this embodiment, YAG-Ce-based fluorescent powder is selected, and its emission spectrum diagram is as shown in Figure 4 the figure. Mix it with the additive in a ratio of 24:1, where the additive contains Al2O3, P2O5, B2O3, and Na2O, and the ratio is 8:21:5:10. Then add 16% of the total mass of deionized water, and stir well for 40 s to prepare the fluorescent film slurry for standby.

[0040] Adopt the coating method to evenly coat the fluorescent film slurry on the side of the aluminum substrate with the dielectric film, and put the aluminum substrate after coating into a high-temperature sintering furnace. Raise the temperature to 400°C at a heating rate of 10°C / min, and hold for 20 minutes. After holding, cool with the furnace. When it is completely cooled, the sintering of the fluorescent film is completed.

[0041] Example 2: Performance test of an aluminum substrate fluorescent wavelength converter manufactured by high-temperature sintering at 400°C

[0042] The fluorescent wavelength converter fabricated in Example 1 was combined with a laser diode to fabricate a white laser light source, and its optical performance was tested. The optical path structure of the white laser light source for testing is as Figure 5 shown, where (501) is a laser diode, (502) is an optical shaping system composed of two convex lenses, and (503) is a fluorescent wavelength converter.

[0043] The test results are shown in Table 1, and the emission spectrum of the system at a rated current of 2 A is as Figure 6 shown.

[0044] Table 1

[0045] Current (A) Luminous Flux (lm) Excitation Light Source Wavelength (nm) Color Temperature (K) 1.0 146 452 11067 1.5 230 452 14225 2.0 367 452 7920 3.0 415 452 17943

[0046] Example 3: Fabricating an aluminum substrate fluorescent wavelength converter by high-temperature sintering at 500 °C.

[0047] To further enhance the resistance of the fluorescent wavelength converter to environmental corrosion and ensure its stability during high-power operation, increasing the film-forming temperature of the fluorescent film is the most direct means to raise the temperature required for the fluorescent film to be damaged or quenched.

[0048] Maintaining the process flow shown in Figure 3 Example 1, SiO2 and Ta2O5 were still selected as dielectric films and deposited on the surface of a 0.3-mm-thick mirror aluminum by electron beam evaporation. To improve the stability of the fluorescent wavelength converter, the sintering temperature was increased from 400 °C to 500 °C while keeping the heating rate and holding time unchanged to enhance the heat resistance of the fluorescent film. Since the sintering temperature of the fluorescent film needs to be increased, the proportion of additives in the fluorescent film slurry needs to be adjusted. The proportions of Al2O3, P2O5, B2O3, and Na2O contained therein were adjusted to 10:20:5:9. At the same time, to maintain the conversion efficiency of the fluorescent wavelength converter during operation, the YAG-Ce-based fluorescent powder and the binder were still mixed at a ratio of 24:1. Deionized water with a total mass of 16% was added to the mixed powder, and it was stirred thoroughly for 40 s to form a fluorescent film slurry for standby.

[0049] The fluorescent film slurry was evenly coated on the side of the aluminum substrate with the dielectric film by the coating method. The aluminum substrate after film coating was placed in a high-temperature sintering furnace. The temperature was raised to 500 °C at a heating rate of 10 °C / min and held for 20 min. After holding, it was cooled with the furnace. After it was completely cooled, the sintering of the fluorescent film was completed.

[0050] Example 4: Performance test of an aluminum substrate fluorescent wavelength converter fabricated by high-temperature sintering at 500 °C

[0051] The fluorescent wavelength converter fabricated in Example 3 was combined with a laser diode to fabricate a structure asFigure 5 The white laser light source shown is subjected to optical performance testing.

[0052] The test results are shown in Table 2, and the emission spectrum of the system at a rated current of 2 A is as Figure 7 shown.

[0053] Table 2

[0054] Current (A) Luminous Flux (lm) Excitation Light Source Wavelength (nm) Color Temperature (K) 1.0 143 452 10059 1.5 233 452 14125 2.0 365 452 7911 3.0 418 452 17899

[0055] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the drawings are only examples and do not limit the present invention. The object of the present invention has been fully and effectively achieved. The function and structural principle of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may have any deformation or modification without departing from the said principle.

Claims

1. A manufacturing method of a metal substrate fluorescence wavelength converter, characterized in that It successively includes the following processes: preparing a metal substrate, depositing a dielectric film on one side of the metal substrate, preparing a phosphor film slurry, forming a phosphor film on the dielectric film, and sintering the phosphor film at high temperature.

2. The manufacturing method of a metal substrate fluorescence wavelength converter according to claim 1, characterized in that The preparation of the metal substrate includes determining that the material type of the metal substrate is one or several of copper and copper alloys, aluminum and aluminum alloys, and silver and silver alloys. The thickness of the metal substrate is between 0.3 mm and 2 mm, the reflectivity of one side is greater than 90%, and the surface roughness is less than 100 nm.

3. The manufacturing method of a metal substrate fluorescence wavelength converter according to claim 1, characterized in that The deposition of the dielectric film on one side of the metal substrate is carried out by using one of the ordinary chemical vapor deposition (CVD), atomic layer deposition (ALD), magnetron sputtering, electron beam evaporation, and thermal evaporation techniques to prepare a dielectric film on the side of the metal substrate with a high reflectivity. The dielectric film is composed of one or several materials among SiO2, TiO2, Ta2O5, Al2O3, ZnO2, SnO2, ZrO2, AlN, and TiN, and its thickness is between 1 nm and 100 nm.

4. The manufacturing method of a metal substrate fluorescence wavelength converter according to claim 1, characterized in that The preparation of the phosphor film slurry is to prepare and mix the phosphor powder, additives, and deionized water in a certain proportion and stir until uniform.

5. The manufacturing method of a metal substrate fluorescence wavelength converter according to claim 4, characterized in that, The phosphor is one or a combination of more than one of the following materials: (Y,Tb)2Al5O 12 :Ce 3+ , (Sr,Ba,Ca)2Si5N8:Eu 2+ , CaAlSiN3:Eu 2+ , BaMgAl 10 O 17 :Eu 2+ , BaMgAl 10 O 17 :Eu 2+ ,Mn 2+ , Ca-alpha-SiAlON:Eu 2+ , Beta-SiAlON:Eu 2+ , (Ca,Sr,Ba)2P2O7:Eu 2+ , (Ca,Sr,Ba)2P2O7:Eu 2+ ,Mn 2+ , (Ca,Sr,Ba)5(PO4)3Cl:Eu 2 + , Lu2SiO5:Ce 3+ , (Ca,Sr,Ba)3SiO5:Eu 2+ , (Ca,Sr,Ba)2SiO4:Eu 2+ , Zn2SiO4:Mn 2+ , BaAl 12 O 19 :Mn 2+ , BaMgAl 14 O 23 :Mn 2+ , SrAl 12 O 19 :Mn 2+ , CaAl 12 O 19 :Mn 2+ , YBO3:Tb 3+ , LuBO3:Tb 3+ , Y2O3:Eu 3+ , Y2SiO5:Eu 3+ , Y3Al5O 12 :Eu 3+ , YBO3:Eu 3+ , Y 0.65 Gd 0.35 BO3:Eu 3+ , GdBO3:Eu 3+ , YVO4:Eu 3+ .

6. The manufacturing method of a metal substrate fluorescence wavelength converter according to claim 4, characterized in that, The additives are one or a combination of several of the following materials: Al2O3, P2O5, B2O3, and Na2O.

7. The manufacturing method of a metal substrate fluorescence wavelength converter according to claim 1, characterized in that, The formation of the phosphor film on the dielectric film is to uniformly form the phosphor film slurry on the dielectric film by means of coating or spraying.

8. The manufacturing method of a metal substrate fluorescence wavelength converter according to claim 1, characterized in that The high-temperature sintering of the phosphor film is completed under the following process conditions: the sintering atmosphere is one of air, nitrogen, or argon, the atmosphere pressure is normal atmospheric pressure of one atmosphere, the sintering temperature is between 300 °C and 600 °C, and the holding time is between 10 minutes and 100 minutes.

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