High color rendering index PoCs phosphor and its preparation method and application

Abstract

The present invention discloses a high color rendering index PoCs phosphor and a preparation method and application thereof. The phosphor is composed of Y3Al5O 12 The YAG (YAG) matrix fluorescent ceramic is the substrate, and the substrate is coated with red fluorescent powder or green fluorescent powder. The present invention coats the fluorescent ceramic substrate with fluorescent powder (such as fluorescent red powder or fluorescent green powder), thereby avoiding the problems of direct blue light and low utilization rate caused by excessively high transmittance of the fluorescent ceramic, and reflects the blue light that directly penetrates the fluorescent ceramic back to the fluorescent ceramic, and is excited again by the activated ions, thereby improving the utilization efficiency of the blue light.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic fluorescent materials, and in particular relates to a high color rendering index ceramic coated phosphor layer (PoCs) fluorescent converter and a preparation method thereof and application in high-power LED packaging. Background Art

[0002] LED lighting has become a new generation of lighting technology due to its environmental friendliness, high brightness, long service life, and energy saving. The principle of LED lighting is: 12 :Ce 3+ The (YAG:Ce) fluorescent material is excited by the LED blue light chip, and the emitted yellow light is mixed with some of the unabsorbed blue light to achieve white light emission. As white light LEDs develop towards high-power of hundreds to kilowatts, high-power LEDs have higher requirements for fluorescent materials. High-power LEDs have high packaging density. When driven by high current (>1500mA), the surface temperature of the COB light source can reach 150-200°C. The development of high-power LEDs is limited by the traditional YAG:Ce phosphor packaging mode. The traditional YAG:Ce phosphor packaging uses resin or silicone and other polymer glue for packaging, and its thermal conductivity is low (0.4Wm -1 K -1 ), poor thermal stability, and too high operating temperature can easily cause problems such as LED color shift, reduced luminous efficiency, and reduced service life.

[0003] Compared with the phosphor glue packaging mode, YAG:Ce fluorescent ceramics have higher thermal conductivity (about 14W m -1 K -1 ), better heat dissipation performance, suitable for use as a fluorescent converter for high-power LEDs. Although high-power white light LEDs packaged with YAG:Ce fluorescent ceramics have been commercialized in large space lighting fields such as stadiums and airports, this packaging method lacks red light components in the YAG:Ce emission spectrum, resulting in a low color rendering index for white light LEDs. In recent years, fluorescent films coated with phosphors on sapphire, borosilicate glass, and transparent ceramics as substrates have also developed rapidly. With the help of the excellent heat dissipation performance of the substrate, phosphor glue is coated on the substrate and cured to obtain a fluorescent film. In order to obtain a fluorescent film with a high color rendering index, it is usually practiced to deposit a variety of mixed phosphors such as green phosphor LuAG:Ce and red phosphor CaAlSiN3:Eu on the substrate, but too much phosphor will seriously reduce the transmittance of light, seriously scatter the light, and affect the light output efficiency of the LED. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a high color rendering index ceramic coated phosphor layer (PoCs) solid-state phosphor and a preparation method and application thereof.

[0005] The technical solution of the present invention is as follows:

[0006] A high color rendering index PoCs phosphor, the phosphor is Y3Al5O 12 The (YAG) matrix fluorescent ceramic is a substrate, and the substrate is coated with red fluorescent powder or green fluorescent powder.

[0007] According to the present invention, the coating thickness of the red phosphor or the green phosphor is 0.1-1 mm, for example, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm.

[0008] According to the present invention, red phosphor or green phosphor is mixed with polymer glue and then coated on the substrate.

[0009] According to the present invention, the polymer glue is polyimide, silica gel, silicone resin or epoxy resin. The silicone resin is preferably phenyl vinyl silicone resin.

[0010] According to the present invention, in step (1), the mass ratio of the green phosphor or the red phosphor to the polymer glue is 1:1-4, preferably 1:1-2.

[0011] According to the present invention, the YAG-based fluorescent ceramic is a known product in the prior art. For example, its preparation method is described in the document Weak thermal quenching and tunable luminescence in Ce:Y3(Al,Sc)5O 12 Transparent ceramics for high power white LEDs / LDs, Chem. Eng. J. 2020, 398, 125486 (DOI: 10.1016 / j.cej.2020.125486); or Opt. Mater. Express, 9, 2019, 3333-3341; or Adv. Mater. 2020, 32, 1907888 (10.1002 / adma.201907888), etc. For example, Ce 3+ Doped Y 3-x- y Ce x M y Al 5-z N z O 12 Fluorescent ceramics, including Ce 3+The doping amount is 0.0001≤x≤0.1; M is selected from Lu, Tb or Gd, 0≤y≤2.9999; N is selected from Ga, Sc or Mg-Si / Ca-Si, 0≤z≤5, and under the excitation of blue light or ultraviolet light LED chip, the peak wavelength is 490nm~600nm; or Mn 4+ Doped Y 3-m M m Al 5-n-p Mn n R p O 12 Fluorescent ceramics, including Mn 4+ The doping amount is 0.001≤n≤0.1, 0.001≤p≤0.1; M is Lu, Tb or Gd, 0≤m≤3; R is Mg, Ca, Ba or Sr; under the excitation of blue light or ultraviolet light LED chip, the peak wavelength is 640nm~680nm.

[0012] According to the present invention, the Ce 3+ Doped Y 3-x-y Ce x M y Al 5-z N z O 12 In the fluorescent ceramic, when M is Lu, Tb or Gd, and N is Ga or Sc, the fluorescent ceramic is a green or yellow fluorescent ceramic.

[0013] According to the present invention, the Ce 3+ Doped Y 3-x-y Ce x M y Al 5-z N z O 12 In the fluorescent ceramic, when M is Lu, Tb or Gd, and N is Mg / Ca-Si, the fluorescent ceramic is a red light fluorescent ceramic.

[0014] According to the present invention, the green or yellow fluorescent ceramic is coated with red fluorescent powder.

[0015] According to the present invention, the red fluorescent ceramic is coated with green fluorescent powder.

[0016] According to the present invention, the green light phosphor is GaYAG, ScYAG, LuAG:Ce, and has a peak wavelength of 480nm to 530nm under the excitation of a blue light or ultraviolet light LED chip.

[0017] According to the present invention, the red phosphor is Sr2SiO4:Eu 2+ , Sr2Si5N8:Eu 2+ ,CaAlSiN3:Eu 2+,α-SiAlON:Eu 2+ 、LuAG:Mn 4+ , under the excitation of blue light or ultraviolet LED chip, the peak wavelength is between 580nm and 650nm.

[0018] Another object of the present invention is to provide a method for preparing the high color rendering index PoCs phosphor, the method comprising:

[0019] (1) Mixing green phosphor or red phosphor with high temperature glue to prepare slurry;

[0020] (2) applying the slurry in step (1) onto the surface of the substrate;

[0021] (3) The substrate coated with the slurry in step (2) is heated to prepare a PoCs phosphor.

[0022] According to the present invention, in step (2), the slurry can be coated on the surface of the substrate by spin coating, spray coating or screen printing.

[0023] According to the present invention, in step (3), the heating temperature is 100-500°C and the heating time is 0.5-4h. For example, the heating temperature is 100°C, 200°C, 300°C, 400°C, 450°C or 500°C.

[0024] According to the present invention, the reaction product in step (3) is rapidly cooled to prepare a PoCs phosphor.

[0025] As a preferred embodiment of the present invention, in step (2), the process flow of the spin coating method is as follows: ① uniformly mix the red phosphor or green phosphor with the high-temperature glue molecule glue to form a stable slurry; ② fix the fluorescent ceramic substrate on a turntable, and uniformly drip the slurry in step ① onto the fluorescent ceramic substrate, control the rotation speed and the dripping amount of the slurry so that the coating thickness is 0.1-1mm, and prepare a combination; ③ place the combination in step ② in an oven for heat treatment at a temperature of 100-500°C for a time of 0.5-4h; ④ take out the product in step ③, and cool it to obtain a PoCs solid-state phosphor.

[0026] As a preferred embodiment of the present invention, in step (2), the process of using the spraying method is as follows: ① uniformly mix the red phosphor or the green phosphor with the high temperature glue to form a stable slurry; ② use a sprayer to uniformly spray the slurry in step ① onto the fluorescent ceramic substrate, and control the deposition thickness to be 0.1-1 mm by the spraying time and the spraying amount; ③ place the combination in step ② in an oven for heat treatment at a temperature of 100-500° C. for a time of 0.5-4 h; ④ take out the product in step ③, and cool it to obtain a PoCs solid-state phosphor.

[0027] As a preferred embodiment of the present invention, in step (2), the process of using screen printing technology is as follows: ① after red phosphor or green phosphor is mixed with high temperature glue evenly, a stable slurry is formed; ② the slurry in step ① is evenly printed on the fluorescent ceramic substrate using a steel screen, and the deposition thickness is controlled to be 0.1-1mm by the height between the steel screen and the fluorescent ceramic; ③ the combination in step ② is placed in an oven for heat treatment at a temperature of 100-500°C for a time of 0.5-4h; ④ the product in step ③ is taken out and cooled to obtain a PoCs solid-state phosphor.

[0028] The present invention also provides a high color rendering index PoCs phosphor prepared by the method.

[0029] The present invention also provides application of the PoCs phosphor in a high-power white light LED device.

[0030] The present invention also provides a white light LED light source device, which contains the above-mentioned PoCs solid-state phosphor.

[0031] According to the present invention, the white light LED light source device further comprises a blue light LED chip excitation light source.

[0032] According to the present invention, the color rendering index of the light source device is 75 to 98, and the luminous efficiency is 80 to 140 lm / W.

[0033] Beneficial effects of the present invention:

[0034] The high color rendering index PoCs solid-state phosphor provided by the present invention has the advantages of high color rendering index, high light efficiency, strong heat dissipation, etc. It is a fluorescent converter suitable for high-power white light LED devices and has good application prospects in the fields of high color rendering index, high-power density white light LED lighting devices, etc. The preparation method of the high color rendering index and high thermal conductivity PoCs solid-state phosphor provided by the present invention has a simple process and is suitable for industrial production.

[0035] (1) The present invention coats fluorescent powder (such as fluorescent red powder or fluorescent green powder) on the surface of the fluorescent ceramic substrate, thereby avoiding the problems of direct blue light and low utilization rate caused by the excessively high transmittance of the fluorescent ceramic. The blue light that directly penetrates the fluorescent ceramic is reflected back to the fluorescent ceramic, and the activated ions are excited again, thereby improving the utilization efficiency of the blue light.

[0036] (2) The present invention achieves red, green and blue color regulation under LED blue light excitation by coating fluorescent red powder on the surface of green or yellow fluorescent ceramics, or coating fluorescent green powder on the surface of red-based fluorescent ceramics, thereby obtaining a PoCs solid-state phosphor with a high color rendering index.

[0037] (3) The present invention uses fluorescent ceramics with high thermal conductivity as a substrate to obtain a high thermal conductivity PoCs solid-state phosphor, which is suitable for use as a high-power LED packaging fluorescent converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the emission spectrum of the PoCs solid-state phosphor in Example 1.

[0039] Figure 2 This is the emission spectrum of the PoCs solid-state phosphor in Example 2. DETAILED DESCRIPTION

[0040] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations 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 included in the scope that the present invention is intended to protect.

[0041] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0042] Example 1

[0043] (1) LuAG:Ce green phosphor with an emission wavelength of 510 nm and polymer glue are mixed in a mass ratio of 1:1, wherein the polymer glue is composed of silica gel to form a uniform slurry;

[0044] (2) Using a spin coating process, the above slurry is evenly coated on the LuAG:Mn 4+ Red light fluorescent ceramics (wherein, YAG matrix fluorescent ceramics are Mn 4+ Doped Lu3Al 4.95 Mn 0.01 Mg 0.04 O 12 ) surface, the thickness of the slurry coating was controlled to be 0.3 mm, calcined in a muffle furnace at 400°C for 1 h, and then taken out and quenched to obtain a PoCs solid-state phosphor.

[0045] (3) The prepared PoCs solid-state phosphor was subjected to a thermal stability test. The results showed that the luminous intensity at 200°C still maintained 92% of that at 25°C.

[0046] (4) The prepared PoCs solid-state phosphor is packaged with a 450nm blue light chip to test its light color performance. Figure 1 As shown, the emission peak is in LuAG:Mn 4+The 510nm green light of LuAG:Ce green phosphor is added to the 650nm and 670nm red light, with a color rendering index of 78 and a luminous efficiency of 115lm / W.

[0047] The results of Example 1 show that the PoCs solid-state phosphor prepared by the method of the present invention has excellent thermal properties and a high color rendering index.

[0048] Example 2

[0049] (1) LuAG:Mn with an emission wavelength of 670nm 4+ The red fluorescent powder and the polymer glue are mixed in a mass ratio of 1:1, wherein the polymer glue is bisphenol A type epoxy resin, to form a uniform slurry;

[0050] (2) Using a spin coating process, the above slurry is evenly coated onto a LuAG:Ce green light fluorescent ceramic with an emission wavelength of 510 nm (the YAG matrix fluorescent ceramic is Lu 2.998 Ce 0.002 Al5O 12 ) surface, the thickness of the slurry coating was controlled to be 0.2 mm, calcined in a muffle furnace at 300°C for 1 h, and then taken out and quenched to obtain a PoCs solid-state phosphor.

[0051] (3) The prepared PoCs solid-state phosphor was subjected to a thermal stability test. The results showed that the luminescence intensity at 200°C still maintained 95% of that at 25°C.

[0052] (4) The prepared PoCs solid-state phosphor is packaged with a 450nm blue light chip to test its light color performance. Figure 2 As shown, the emission peak is in LuAG:Ce 3+ On the basis of 510nm green light, Mn 4+ At 650nm and 670nm red light emission, the color rendering index is 82 and the luminous efficiency reaches 105lm / W.

[0053] It is shown that the PoCs solid-state phosphor prepared by the method of the present invention has excellent heat dissipation performance and a high color rendering index.

[0054] Example 3

[0055] (1) Sr2Si5N8:Eu with an emission wavelength of 610nm 2+ The red phosphor and the polymer glue are mixed in a mass ratio of 1:2, wherein the polymer glue is composed of phenyl vinyl silicone resin to form a uniform slurry;

[0056] (2) Using a spin coating process, the above slurry is evenly coated onto a LuAG:Ce green light fluorescent ceramic with an emission wavelength of 510 nm (the YAG matrix fluorescent ceramic is Lu 2.999 Ce 0.001 Al5O 12 ) surface, the slurry coating thickness was controlled to be 0.4 mm, calcined in a muffle furnace at 450°C for 1 h, and then taken out and quenched to obtain a PoCs solid-state phosphor;

[0057] (3) The prepared PoCs solid-state phosphor was subjected to a thermal stability test. The results showed that the luminescence intensity at 200°C still maintained 90% of that at 25°C.

[0058] (4) The prepared PoCs solid-state phosphor was packaged with a 450nm blue light chip to test its light color performance. The emission peak was supplemented with Eu based on the 510nm green light emission of LuAG:Ce. 2+ At 610nm red light component, the color rendering index is 85 and the luminous efficiency reaches 95lm / W.

[0059] It is shown that the PoCs solid-state phosphor prepared by the method of the present invention has excellent heat dissipation performance and high color rendering index.

[0060] The above is an exemplary description of the embodiments of the present invention. However, the protection scope of the present invention is not limited to the above embodiments. Any modification, equivalent substitution, improvement, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a phosphor, characterized in that: The preparation method comprises: (1) Mixing green phosphor and polymer glue to prepare slurry; (2) applying the slurry in step (1) onto the surface of the substrate; (3) heating the substrate coated with the slurry in step (2) to prepare a phosphor; The phosphor is Y3Al5O 12 The base fluorescent ceramic is a substrate, the fluorescent ceramic is a red fluorescent ceramic; the Y3Al5O 12 The base fluorescent ceramic is Ce 3+ Doped Fluorescent ceramics, or Mn-doped Lu3Al 4.95 Mn 0.01 Mg 0.04 O 12 ; The Ce 3+ Doped In fluorescent ceramics, when M is Lu, Tb or Gd, N is ; Among them, 0.0001≤ x ≤0.1,0≤ y ≤2.9999; 0≤ z ≤5; The green phosphor is GaYAG, ScYAG, LuAG:Ce, and has a peak wavelength of 480nm~530nm under the excitation of blue light or ultraviolet light LED chip; In step (3), the heating temperature is 300-500°C.

2. A method for preparing a phosphor, characterized in that: The preparation method comprises: (1) Mixing red phosphor and polymer glue to prepare slurry; (2) applying the slurry in step (1) onto the surface of the substrate; (3) heating the substrate coated with the slurry in step (2) to prepare a phosphor; The phosphor is Y3Al5O 12 The base fluorescent ceramic is a substrate, the fluorescent ceramic is a green fluorescent ceramic; the Y3Al5O 12 The base fluorescent ceramic is Ce 3+ Doped Fluorescent ceramics; The Ce 3+ Doped Y 3-x-y Ce x M y Al 5-z N z O 12 In fluorescent ceramics, when M is Lu, Tb or Gd, and N is Ga or Sc, 0.0001≤ x ≤0.1,0≤ y ≤2.9999; 0≤ z ≤5; The red phosphor is Sr2SiO4:Eu 2+ , Sr2Si5N8:Eu 2+ ,CaAlSiN3:Eu 2+ ,α-SiAlON:Eu 2+ 、LuAG:Mn 4+ , under the excitation of blue light or ultraviolet light LED chip, the peak wavelength is 580nm~650nm; In step (3), the heating temperature is 300-500°C.

3. The method according to claim 1 or 2, characterized in that: The coating thickness of the red phosphor or the green phosphor is 0.1-1 mm.

4. The method according to claim 1 or 2, characterized in that: The polymer glue is at least one of polyimide, silica gel, silicone resin and epoxy resin.

5. The method according to claim 1 or 2, characterized in that: In step (1), the mass ratio of the green phosphor or the red phosphor to the polymer glue is 1:1-4.

6. The method according to claim 1 or 2, characterized in that: In step (3), the heating time is 0.5-4h.

7. Use of the phosphor prepared by the method according to any one of claims 1 to 6 in a high-power white light LED device.

8. A white light LED light source device, characterized in that: The light source device contains a phosphor prepared by the method according to any one of claims 1-6.

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