High-color-rendering fluorescent color wheel as well as preparation method and application thereof

Abstract

The invention relates to a high-color-rendering fluorescent color wheel as well as a preparation method and application thereof. The fluorescent color wheel comprises a yellow fluorescent color wheel layer and a red fluorescent color wheel layer which is at least partially arranged on the yellow fluorescent color wheel layer in a covering manner; the yellow fluorescent color wheel layer comprises a first gel main body and yellow fluorescent powder dispersed in the first gel main body; the red fluorescent color wheel layer comprises a second gel main body and red fluorescent powder dispersed in the second gel main body; the yellow light fluorescent powder is YAG: Ce yellow light fluorescent powder; the red-light fluorescent powder is MgO-TiO2-MnO2 red-light fluorescent powder, and the red-light fluorescent powder comprises the following components in percentage by mass of oxides: more than 3% and less than or equal to 9.07% of MnO2, more than 48% and less than or equal to 56.43% of MgO, and more than 24% and less than or equal to 34.49% of TiO2. Compared with the prior art, a two-step gel casting process is innovatively adopted, the novel fluorescent color wheel integrating the yellow fluorescent powder and the red fluorescent powder is prepared, and the service life of the fluorescent color wheel is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluorescent materials, and particularly relates to a high-color rendering fluorescent color wheel, a preparation method thereof and an application thereof. Background Art

[0002] Semiconductor lighting LED technology is regarded as the fourth-generation lighting source due to its advantages such as high luminous efficiency (LE), low energy consumption, long lifespan, and environmental friendliness, and is increasingly applied in fields such as lighting and display. Traditional white LED mainly adopts a method of mixing and encapsulating a blue light chip excitation and a fluorescent yellow powder (YAG:Ce) organic glue. With economic development and social progress, large-space high-illuminance lighting places such as oceans, ports, stadiums, airports, and roads are increasing day by day, and the high-powerization of LED light sources has become one of the important development trends in the LED lighting industry. The performance of white LED light sources based on blue light chips is not only restricted by the poor heat dissipation of the chips themselves, but also aging phenomena will occur under high temperature or strong light irradiation, which will further lead to problems such as decreased luminous efficiency, light decay, color drift (such as white LED turning blue), and short lifespan.

[0003] The light efficiency loss and color limitation of traditional fluorescent color wheels are broken through by the direct wavelength conversion of fluorescent materials. The main method for manufacturing fluorescent color wheels at present is to coat and encapsulate fluorescent powder on a highly reflective substrate. Compared with traditional color filters, the advantages of fluorescent color wheels are: high brightness output, which can significantly improve brightness, especially showing better performance in strong light environments, having a wider color gamut and more excellent color performance; reducing energy consumption, extending the lifespan of light sources, reducing maintenance frequency, and being suitable for commercial scenarios; reducing waste pollution, being suitable for the trend of green energy, and meeting the market demand.

[0004] However, the fluorescent materials in the fluorescent color wheel will accumulate heat under continuous excitation of high-power lasers. For example, when blue laser excites fluorescent yellow powder YAG:Ce, the temperature will rise, which will further reduce the luminous efficiency of the fluorescent materials. In addition, due to the lack of red light components in the light sources of existing fluorescent color wheels, the problem of low color rendering / color gamut often occurs. CN117776687A discloses a ceramic-glass ceramic thin film composite structure fluorescent color wheel for white LD lighting and a preparation method thereof. The fluorescent color wheel includes a transparent ceramic substrate and a two-color fluorescent glass ceramic thin film distributed on the upper surface of the transparent ceramic substrate, and the two-color fluorescent glass ceramic thin film is a composite structure composed of a cyan light-emitting fluorescent glass ceramic thin film and an orange-red light-emitting fluorescent glass ceramic thin film. However, although the above fluorescent color wheel increases the red light component, the fluorescent powder in the fluorescent color wheel can only be coated on the surface of the ceramic substrate, and when excited by high energy, it is still easy to cause the temperature to rise rapidly, accelerating the degradation of the fluorescent powder layer on the surface of the substrate and shortening the service life of the color wheel.

[0005] Therefore, there is still a need to develop a new type of fluorescent color wheel that takes into account both yellow and red light components. Summary of the Invention

[0006] An object of the present invention is to provide a high-color rendering fluorescent color wheel, a preparation method thereof and an application thereof, in order to overcome the defects of the existing fluorescent color wheel, such as the lack of red light component and the easy degradation of the fluorescent powder layer.

[0007] The object of the present invention can be achieved by the following technical solutions:

[0008] The present invention first provides a high-color rendering fluorescent color wheel, which includes a yellow light fluorescent color wheel layer and a red light fluorescent color wheel layer disposed on at least part of the yellow light fluorescent color wheel layer; the yellow light fluorescent color wheel layer includes a first gel main body and yellow light fluorescent powder dispersed in the first gel main body; the red light fluorescent color wheel layer includes a second gel main body and red light fluorescent powder dispersed in the second gel main body;

[0009] Among them, both the first gel main body and the second gel main body are prepared from the following raw material components in parts by weight: 4-6 parts of N,N-dimethylacrylamide, 0.2-0.3 parts of N,N-methylenebisacrylamide, 6-7 parts of dispersant, 2-4 parts of catalyst, 0.8-1.2 parts of initiator;

[0010] The yellow light fluorescent powder is YAG:Ce yellow light fluorescent powder; the red light fluorescent powder is MgO-TiO2-MnO2 red light fluorescent powder. The components in the red light fluorescent powder are in mass percentage of oxides: 3% < MnO2 ≤ 9.07%, 48% < MgO ≤ 56.43%, 24% < TiO2 ≤ 34.49%.

[0011] Further, in the yellow light fluorescent color wheel layer, the mass ratio of the first gel main body to the yellow light fluorescent powder is (19-23):100.

[0012] Further, in the yellow light fluorescent color wheel layer, the mass ratio of the second gel main body to the red light fluorescent powder is (19-23):100.

[0013] Further, the average particle size of the yellow light fluorescent powder is 15μm.

[0014] Further, the average particle size of the red light fluorescent powder is 20μm.

[0015] Further, the dispersant includes one or more of ammonium polyacrylate, ammonium polymethacrylate, ammonium citrate, and preferably ammonium polyacrylate.

[0016] Further, the catalyst includes one or more of N,N,N,N-tetramethylethylenediamine, ferrous sulfate and persulfate (KPS), and preferably N,N,N,N-tetramethylethylenediamine (TEMED).

[0017] Further, the initiator includes one or more of ammonium persulfate and potassium persulfate, preferably ammonium persulfate (APS).

[0018] Further, the yellow fluorescent color wheel layer has a cylindrical structure, with a diameter of 90 - 110 mm, preferably 100 mm; and a height of 4 - 6 mm, preferably 5 mm.

[0019] Further, the red fluorescent color wheel layer is one or a combination of more of an annular shape, a sector shape, and a circular shape that can partially cover the yellow fluorescent color wheel layer, preferably a sector shape symmetrically distributed at 90°.

[0020] Further, the height of the yellow fluorescent color wheel layer is 4 - 6 mm, preferably 5 mm.

[0021] Further, the emission spectrum range of the yellow fluorescent powder under 460 nm blue light excitation is 500 - 650 nm.

[0022] Further, the emission spectrum range of the red fluorescent powder under 365 nm violet light excitation is 520 - 750 nm.

[0023] Further, the color rendering index of the fluorescent color wheel is not less than 85.

[0024] The present invention also provides a preparation method for a high color rendering fluorescent color wheel, and the preparation method includes the following steps:

[0025] S1. Prepare a green body of the yellow fluorescent color wheel layer:

[0026] Mix the yellow fluorescent powder with a premixed solution composed of N,N - dimethylacrylamide, N,N - methylenebisacrylamide, a dispersant, and water, and perform ball milling. Add a catalyst during the ball milling process to form a first mixed slurry; add an initiator to the first mixed slurry and pour it into a mold, and obtain a green body of the yellow fluorescent color wheel layer after drying.

[0027] S2. Prepare a green body of the fluorescent color wheel:

[0028] Mix the red fluorescent powder with the premixed solution and perform ball milling. Add a catalyst during the ball milling process to form a second mixed slurry; add an initiator to the second mixed slurry, and then pour the second mixed slurry onto the green body of the red fluorescent color wheel layer in the mold, and obtain a green body of the fluorescent color wheel after drying.

[0029] S3. Prepare the fluorescent color wheel:

[0030] Subject the green body of the fluorescent color wheel obtained in S2 to high - temperature calcination, and the fluorescent color wheel is obtained after cooling.

[0031] Further, in steps S1 and S2, the ball milling time is 24 - 36 h for both.

[0032] Further, in steps S1 and S2, the rotation speed of the ball milling is 250 - 350 rpm, preferably 300 rpm.

[0033] Furthermore, in steps S1 and S2, the catalyst is added 0.5 - 1 h before the end of the ball milling to avoid premature polymerization.

[0034] Furthermore, the drying temperature is 45 - 80°C and the drying time is 1.5 - 3 h. Preliminary mixing during injection molding is carried out at a low temperature (such as 5 - 10°C) to delay the reaction, and the temperature is raised to 25 - 40°C in the second step to initiate polymerization. The gelation time is controlled within 10 - 60 min by adjusting the initiator concentration. During curing, a preliminary gel network is first formed at a lower temperature, and then the temperature is raised to 50 - 80°C to complete crosslinking and improve the strength of the green body.

[0035] Further, in step S2, the preparation method of the red phosphor is as follows: Weigh MgO, TiO2, and MnO2 and grind and mix them evenly, and then perform high-temperature calcination to obtain the red phosphor.

[0036] Furthermore, the grinding time is 15 - 30 min.

[0037] Furthermore, the temperature of the high-temperature calcination is 1100 - 1300°C, preferably 1200°C.

[0038] Furthermore, the time of the high-temperature calcination is 6 - 8 h.

[0039] Further, in step S3, the temperature of the high-temperature calcination is 1100 - 1300°C, preferably 1200°C.

[0040] Further, in step S3, the time of the high-temperature calcination is 6 - 8 h.

[0041] The present invention adopts the gel injection molding method. By injecting the slurry mixed with phosphor into the mold for in-situ curing, and by adjusting the solid content of the slurry, the type and dosage of the dispersant, the rheological properties are optimized to ensure that the slurry can fill the details of the mold and avoid sedimentation or agglomeration. The synergistic regulation of the catalyst, initiator, and temperature can achieve flexible adjustment of the gel time to meet the production requirements of different scales. Through the optimization of the solid content and dispersant, the drying shrinkage rate can be controlled within 2 - 5%.

[0042] The present invention also provides an application of the high-color rendering fluorescent color wheel in laser lighting, high-power LEDs, and projection displays. The fluorescent color wheel can be used for remote packaging of chips to avoid direct contact between the phosphor material and the chip energy source, thereby improving the heat dissipation performance of the device.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The present invention innovatively adopts a two-step gel injection molding process to produce a new fluorescent color wheel that takes into account both yellow phosphor and red phosphor. The two phosphor powders are evenly dispersed in the gel matrix, which overcomes the defect of the traditional fluorescent color wheel that only coats the fluorescent material on the surface, reduces the long-term direct contact between the phosphor material and the chip energy source, and thus reduces the degradation rate of the fluorescent material, thereby improving the service life of the fluorescent color wheel.

[0045] (2) The fluorescent color wheel of the present invention uses MgO-TiO2-MnO2 red phosphor and YAG:Ce yellow phosphor as raw materials. Through the ingenious design of the double-layer gel layer, the two fluorescent components are staggered, and a new color wheel that takes into account both yellow light and red light components is successfully produced, which can effectively improve the color rendering index of the fluorescent color wheel.

[0046] (3) The fluorescent color wheel of the present invention is prepared by a two-step gel injection molding process, which has a simple preparation method, high solid content, adjustable product shape and size, and can be prepared in batches with a high yield.

[0047] (4) The high color rendering fluorescent color wheel of the present invention can be used for remote packaging of chips to avoid direct contact between the phosphor material and the chip energy source, thereby improving the heat dissipation performance of the device. It can be widely used in laser lighting, high-power LEDs, projection displays and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the structure of the fluorescent color wheel of the present invention.

[0049] Figure 2 This is a physical picture of the fluorescent color wheel of the present invention.

[0050] Figure 3 This is the XRD spectrum of the red phosphor in Example 1 of the present invention.

[0051] Figure 4 This is a photoexcitation-emission spectrum of the red phosphor in Example 1 of the present invention. DETAILED DESCRIPTION

[0052] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0053] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0054] The YAG:Ce yellow phosphor in the following examples is selected from Wisbol Optoelectronics (Suzhou) Co., Ltd., model Lot#: 1708001, and the doping amount of Ce is 18 mol%.

[0055] Example 1:

[0056] (1) Accurately weigh 200 g of YAG:Ce yellow phosphor, and mix the YAG:Ce powder with the premixed solution. The masses of each component in the premixed solution are as follows: 30 g of deionized water, 5 g of N,N-dimethylacrylamide, 0.26 g of N,N-methylenebisacrylamide, and 6.5 g of ammonium polyacrylate. The mass of the powder added for the first time is 120 g, and 40 g is added in two portions after ball milling for 6 h and 12 h respectively. 3 g of 5 wt% N,N,N,N-tetramethylethylenediamine is added to the slurry 30 min before the end of ball milling.

[0057] (2) Pour the ball-milled slurry into a beaker, add 1 g of 1.5 wt% ammonium persulfate thereto, and stir rapidly. Filter the air bubbles in the slurry through a 200-mesh stainless steel sieve, and then quickly pour the slurry into a pre-prepared inert silica gel mold. After standing for about 12 h, dry it in an oven at 50 °C for 2 h, demold it, and continue drying for 12 h to obtain a green phosphor green body.

[0058] (3) According to the component ratio of MgO-TiO2-MnO2 = 100.45:99.27:0.27 (by the mass of oxides), accurately weigh a total of 200 g of the sample. After the raw materials are crushed, ground, and mixed evenly, put them into a high-temperature furnace and calcine them in an air atmosphere at 1200 °C for 6 - 8 h, and cool to room temperature to obtain a red phosphor.

[0059] (4) Mix the red phosphor with the premixed solution. The masses of each component in the premixed solution are as follows: 30 g of deionized water, 5 g of N,N-dimethylacrylamide, 0.26 g of N,N-methylenebisacrylamide, and 6.5 g of ammonium polyacrylate. The mass of the powder added for the first time is 120 g, and 40 g is added in two portions after ball milling for 6 h and 12 h respectively. 3 g of 5 wt% N,N,N,N-tetramethylethylenediamine is added to the slurry 30 min before the end of ball milling.

[0060] (5) Pour the ball-milled slurry into a beaker, add 1 g of 1.5 wt% ammonium persulfate thereto, and stir rapidly. Filter the air bubbles in the slurry through a 200-mesh stainless steel sieve, and then quickly pour the slurry onto the inverted YAG:Ce green body. After standing for about 24 h, dry it in an oven at 50 °C for 2 h, demold it, and continue drying for 24 h to obtain the final green body.

[0061] (6) Place the green body into a high-temperature furnace and calcine it for 6 h under the condition of an air atmosphere at 1200 °C to obtain a color wheel. After taking out the color wheel from the high-temperature furnace, cool it to room temperature and perform grinding and polishing to obtain the final fluorescent color wheel.

[0062] The structural schematic diagram of the fluorescent color wheel in this embodiment is as Figure 1 shown. The yellow light fluorescent color wheel layer is a cylindrical structure with a diameter of 100 mm and a height of 5 mm. The red light fluorescent color wheel layer is a fan-shaped structure that can partially cover the yellow light fluorescent color wheel layer, with a height of 5 mm, and the specific shape is a symmetrically distributed 90° fan. From Figure 2 it can be seen that under the excitation of ultraviolet light and blue light at 365 and 460 nm, the fluorescent color wheel of this embodiment can emit bright yellow light and red light.

[0063] In this embodiment, X-ray diffraction is used to test the crystal structure of the MgO-TiO2-MnO2 red light fluorescent powder. Cu-Kα is used as the target material for testing, and the scanning angle 2θ ranges from 10 - 8° to obtain the XRD ray diffraction pattern as Figure 3 shown.

[0064] In this embodiment, a fluorescence spectrometer (HITACHI F-7500) is also used to test the spectral properties of the MgO-TiO2-MnO2 red light fluorescent powder. As Figure 4 it can be seen that the core excitation wavelength of the MgO-TiO2-MnO2 red light fluorescent powder prepared in this embodiment is 365 nm, and the emission spectrum range under the excitation of 365 nm ultraviolet light is 520 - 750 nm.

[0065] Example 2:

[0066] (1) Accurately weigh 200 g of YAG:Ce yellow fluorescent powder, and mix the YAG:Ce powder with the premixed solution. The masses of each component in the premixed solution are as follows: 30 g of deionized water, 5 g of N,N-dimethylacrylamide, 0.26 g of N,N-methylenebisacrylamide, and 6.5 g of ammonium polyacrylate. The mass of the powder added for the first time is 120 g, and 40 g is added in two times after ball milling for 8 h and 8 h respectively. 3 g of 5 wt% N,N,N,N-tetramethylethylenediamine is added to the slurry 30 min before the end of the final ball milling.

[0067] (2) Pour the ball-milled slurry into a beaker, add 1 g of 1.5 wt% ammonium persulfate to it, and stir quickly. Filter the bubbles in the slurry through a 200-mesh stainless steel sieve, and then quickly pour the slurry into a pre-prepared inert silica gel mold. After standing for about 12 h, place it in an oven at 50 °C for drying for 2 h, demold, and continue drying for 12 h to obtain the YAG:Ce green body.

[0068] (3) Weigh accurately a sample with a total mass of 200 g according to the component ratio of MgO-TiO2-MnO2 = 100.45:99.27:0.27 (by the mass of oxides). After the raw materials are crushed, ground and mixed evenly, put them into a high-temperature furnace and calcine for 6 - 8 h under the condition of an air atmosphere at 1200 °C, then cool to room temperature to obtain the red phosphor.

[0069] (4) Mix the red phosphor with the premixed solution. The masses of each component in the premixed solution are as follows: 30 g of deionized water, 5 g of N,N-dimethylacrylamide, 0.26 g of N,N-methylenebisacrylamide, and 6.5 g of ammonium polyacrylate. The mass of the powder added for the first time is 120 g, and 40 g is added in two separate times after 8 h and 8 h of ball milling. And 3 g of 5 wt% N,N,N,N-tetramethylethylenediamine is added to the slurry 30 min before the end of ball milling.

[0070] (5) Pour the slurry after ball milling into a beaker, add 1 g of 1.5 wt% ammonium persulfate to it, and stir quickly. Filter the air bubbles in the slurry through a 200-mesh stainless steel sieve, and then quickly pour the slurry onto the inverted YAG:Ce green body. After standing for about 24 h, place it in an oven and dry at 50 °C for 2 h, then demold and continue drying for 24 h to obtain the final green body.

[0071] (6) Put the green body into a high-temperature furnace and calcine for 6 h under the condition of an air atmosphere at 1300 °C to prepare the color wheel. After taking the color wheel out of the high-temperature furnace, cool it to room temperature and polish it to obtain the final fluorescent color wheel.

[0072] Example 3:

[0073] (1) Weigh accurately 200 g of YAG:Ce yellow phosphor. Mix the YAG:Ce powder with the premixed solution. The masses of each component in the premixed solution are as follows: 30 g of deionized water, 5 g of N,N-dimethylacrylamide, 0.26 g of N,N-methylenebisacrylamide, and 6.5 g of ammonium polyacrylate. The mass of the powder added for the first time is 120 g, and 40 g is added in two separate times after 8 h and 12 h of ball milling. And 3 g of 5 wt% N,N,N,N-tetramethylethylenediamine is added to the slurry 30 min before the end of ball milling.

[0074] (2) Pour the slurry after ball milling into a beaker, add 1 g of 1.5 wt% ammonium persulfate to it, and stir quickly. Filter the air bubbles in the slurry through a 200-mesh stainless steel sieve, and then quickly pour the slurry into a pre-prepared inert silica gel mold. After standing for about 12 h, place it in an oven and dry at 50 °C for 2 h, then demold and continue drying for 12 h to obtain the YAG:Ce green body.

[0075] (3) Weigh accurately a sample with a total mass of 200 g according to the component ratio of MgO-TiO2-MnO2 = 100.45:99.27:0.27 (by the mass of oxides). After the raw materials are crushed, ground and mixed evenly, put them into a high-temperature furnace and calcine for 6 - 8 h under the condition of air atmosphere at 1200 °C, then cool to room temperature to obtain the red phosphor.

[0076] (4) Mix the red phosphor with the premixed solution. The masses of each component in the premixed solution are as follows: 30 g of deionized water, 5 g of N,N-dimethylacrylamide, 0.26 g of N,N-methylenebisacrylamide, and 6.5 g of ammonium polyacrylate. The mass of the powder added for the first time is 120 g, and 40 g are added twice after ball milling for 8 h and 12 h respectively. And 3 g of 5 wt% N,N,N,N-tetramethylethylenediamine is added to the slurry 30 min before the end of ball milling.

[0077] (5) Pour the slurry after ball milling into a beaker, add 1 g of 1.5 wt% ammonium persulfate to it, and stir quickly. Filter the air bubbles in the slurry through a 200-mesh stainless steel sieve, and then quickly pour the slurry onto the inverted YAG:Ce green body. After standing for about 48 h, place it in an oven and dry at 50 °C for 2 h, then demold and continue to dry for 36 h to obtain the final green body.

[0078] (6) Put the green body into a high-temperature furnace and calcine for 8 h under the condition of air atmosphere at 1400 °C to prepare the color wheel. After taking out the color wheel from the high-temperature furnace, cool it to room temperature and polish it to obtain the final fluorescent color wheel.

[0079] Example 4:

[0080] (1) Weigh accurately 200 g of YAG:Ce yellow phosphor. Mix the YAG:Ce powder with the premixed solution. The masses of each component in the premixed solution are as follows: 30 g of deionized water, 5 g of N,N-dimethylacrylamide, 0.26 g of N,N-methylenebisacrylamide, and 6.5 g of ammonium polyacrylate. The mass of the powder added for the first time is 120 g, and 40 g are added twice after ball milling for 6 h and 8 h respectively. And 3 g of 5 wt% N,N,N,N-tetramethylethylenediamine is added to the slurry 30 min before the end of ball milling.

[0081] ((2) Pour the slurry after ball milling into a beaker, add 1 g of 1.5 wt% ammonium persulfate to it, and stir quickly. Filter the air bubbles in the slurry through a 200-mesh stainless steel sieve, and then quickly pour the slurry into a pre-prepared inert silica gel mold. After standing for about 12 h, place it in an oven and dry at 50 °C for 2 h, then demold and continue to dry for 12 h to obtain the YAG:Ce green body.

[0082] (3) Weigh accurately a total of 200 g of the sample according to the component ratio of MgO-TiO2-MnO2 = 100.45:99.27:0.27 (by the mass of oxides). After the raw materials are crushed, ground and mixed evenly, put them into a high-temperature furnace and calcine for 6-8 h under the condition of air atmosphere at 1200 °C, then cool to room temperature to obtain the red phosphor.

[0083] (4) Mix the red phosphor with the premixed solution. The masses of each component in the premixed solution are as follows: 30 g of deionized water, 5 g of N,N-dimethylacrylamide, 0.26 g of N,N-methylenebisacrylamide, and 6.5 g of ammonium polyacrylate. The mass of the powder added for the first time is 120 g, and 40 g are added in two times after ball milling for 6 h and 8 h respectively. And 3 g of 5 wt% N,N,N,N-tetramethylethylenediamine is added to the slurry 30 min before the end of ball milling.

[0084] (5) Pour the slurry after ball milling into a beaker, add 1 g of 1.5 wt% ammonium persulfate thereto, and stir quickly. Filter the air bubbles in the slurry through a 200-mesh stainless steel sieve, and then quickly pour the slurry onto the inverted YAG:Ce green body. After standing for about 48 h, dry it in an oven at 50 °C for 2 h, demold it, and continue to dry for 48 h to obtain the final green body.

[0085] (6) Put the green body into a high-temperature furnace and calcine for 8 h under the condition of air atmosphere at 1400 °C to prepare the color wheel. After taking out the color wheel from the high-temperature furnace, cool it to room temperature and polish it to obtain the final fluorescent color wheel.

[0086] In summary, the present invention innovatively adopts a two-step gel casting process to prepare a novel fluorescent color wheel that combines yellow phosphor and red phosphor. The two fluorescent powders are evenly dispersed in the gel matrix, overcoming the defect that the traditional fluorescent color wheel only coats the fluorescent material on the surface layer, reducing the long-term direct contact between the phosphor material and the chip energy source, thereby reducing the degradation rate of the fluorescent material and improving the service life of the fluorescent color wheel.

[0087] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. Persons familiar with the art can obviously make various modifications to these embodiments easily and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A high color rendering fluorescent color wheel, characterized in that: The fluorescent color wheel comprises a yellow fluorescent color wheel layer and a red fluorescent color wheel layer at least partially covering the yellow fluorescent color wheel layer; The yellow fluorescent color wheel layer includes a first gel body and yellow fluorescent powder dispersed in the first gel body; the red fluorescent color wheel layer includes a second gel body and red fluorescent powder dispersed in the second gel body; The first gel body and the second gel body are both prepared from the following raw material components in parts by weight: 3-6 parts of N,N-dimethylacrylamide, 0.2-0.3 parts of N,N-methylenebisacrylamide, 6-7 parts of dispersant, 2-4 parts of catalyst, and 0.8-1.2 parts of initiator; The yellow phosphor is YAG:Ce yellow phosphor; the red phosphor is MgO-TiO2-MnO2 red phosphor, and the components in the red phosphor are calculated as the mass percentage of oxides as follows: 3% < MnO2 ≤ 9.07%, 48% < MgO ≤ 56.43%, and 24% < TiO2 ≤ 34.49%.

2. The high color rendering fluorescent color wheel according to claim 1, characterized in that: In the yellow fluorescent color wheel layer, the mass ratio of the first gel body to the yellow fluorescent powder is (19-23):100; In the yellow fluorescent color wheel layer, the mass ratio of the second gel body to the red fluorescent powder is (19-23):

100.

3. The high color rendering fluorescent color wheel according to claim 1, characterized in that: The yellow fluorescent color wheel layer is a cylindrical structure with a diameter of 90-110 mm and a height of 4-6 mm; The red fluorescent color wheel layer is in the shape of a ring, a sector, or a circle, or a combination thereof, which can partially cover the yellow fluorescent color wheel layer. The height of the yellow fluorescent color wheel layer is 4-6 mm.

4. The high color rendering fluorescent color wheel according to claim 1, characterized in that: The emission spectrum of the yellow phosphor under 460nm blue light excitation is in the range of 500-650nm; The emission spectrum of the red phosphor under 365nm violet light excitation ranges from 620nm to 750nm.

5. The high color rendering fluorescent color wheel according to claim 1, characterized in that: The color rendering index of the fluorescent color wheel is not less than 85.

6. A method for preparing a high color rendering fluorescent color wheel according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: S1. Preparation of yellow fluorescent color wheel layer embryos: The yellow fluorescent powder is mixed with a premixed solution consisting of N,N-dimethylacrylamide, N,N-methylenebisacrylamide, a dispersant, and water, and a catalyst is added during the ball milling process to form a first mixed slurry; an initiator is added to the first mixed slurry, and the mixture is poured into a mold, and dried to obtain a yellow fluorescent color wheel layer embryo; S2. Preparation of fluorescent whorl embryos: The red fluorescent powder and the premixed liquid are mixed and ball-milled, and a catalyst is added during the ball-milling process to form a second mixed slurry; an initiator is added to the second mixed slurry, and then the second mixed slurry is poured onto the red fluorescent color wheel layer embryo in the mold, and dried to obtain the fluorescent color wheel embryo; S3. Preparation of fluorescent color wheel: The fluorescent color wheel embryo obtained in S2 is calcined at high temperature, and then cooled to obtain the fluorescent color wheel.

7. The method for preparing a high color rendering fluorescent color wheel according to claim 6, wherein: In steps S1 and S2, the ball milling time is 24-36 hours, the ball milling speed is 250-350 rpm, and the catalyst is added 0.5-1 hour before the end of ball milling; The drying temperature is 45-80° C., and the drying time is 1.5-3 hours.

8. The method for preparing a high color rendering fluorescent color wheel according to claim 6, wherein: In step S2, the red phosphor is prepared by weighing MgO, TiO2 and MnO2, grinding and mixing them uniformly, and then calcining them at a high temperature to obtain the red phosphor; The grinding time is 15-30min; The high-temperature calcination temperature is 1100-1300° C., and the high-temperature calcination time is 6-8 hours.

9. The method for preparing a high color rendering fluorescent color wheel according to claim 6, wherein: In step S3, the high-temperature calcination temperature is 1100-1300° C., and the high-temperature calcination time is 6-8 hours.

10. Use of the high color rendering fluorescent color wheel according to any one of claims 1 to 5 in laser lighting, high-power LEDs, and projection displays.

Images