Ultrathin high-luminous-efficiency fluorescent ceramic and preparation method therefor, and chip-scale white light LED device

Abstract

Disclosed in the present invention are an ultrathin high-luminous-efficiency fluorescent ceramic and a preparation method therefor, and a chip-scale white light LED device. The chemical formula of the fluorescent ceramic is Y3-x-y(Al1-wAw)2(Al1-zXz)3O12:xCe3+, yR3+, wA2+, zX4+, wherein 0<x≤0.03, 0≤y≤2.0, x+y≤2.0, 0≤w≤1.0, and 0≤z≤1.0. The fluorescent ceramic of the present invention has the characteristics of an ultrathin thickness, high luminous efficiency, and high thermal stability, has an emission spectrum adjustable within 530-560 nm, and satisfies high-power density packaging of chip-scale LED devices. A white light LED device packaged using the ceramic has the advantages of a small volume, long service life, high light intensity, etc. The chromaticity coordinates of the white light LED are: CIE-x=0.29-0.35 and CIE-y=0.29-0.35, and the white light LED is suitable for use in illumination and display fields such as automobile headlamps and micro projections.

Description

Ultra-thin high-light-efficiency fluorescent ceramic, preparation method thereof, and chip-level white light LED device

[0001] This application claims the benefit of priority to a prior application filed with the State Intellectual Property Office of China on February 18, 2024, with patent number 202410181643.4, entitled “An Ultra-Thin High-Efficiency Fluorescent Ceramic, Its Preparation Method, and Chip-Scale White-Light LED Device.” The entire text of the prior application is incorporated herein by reference. Technical Field

[0002] The present invention relates to the technical field of luminescent materials, and in particular to an ultra-thin high-light-efficiency fluorescent ceramic, a preparation method thereof, and a chip-level white light LED device. Background Art

[0003] Traditional white LED lighting is packaged in the form of phosphor glue. 12 :Ce 3+ (YAG:Ce) yellow powder is evenly dispersed in epoxy resin. High-power density packaged white LEDs reach chip temperatures of 150-200°C. Because epoxy resin has poor heat dissipation and easily decomposes when heated, long-term high-temperature operation of white LEDs can lead to problems such as a sudden drop in luminous efficacy, color coordinate shifts, and package failure.

[0004] With the rise of smart cars and intelligent cockpits, the automotive white LED market is booming, enabling intelligent features such as alternating high and low beams, anti-glare high beam lighting, lane illumination, and positioning lighting. Matrix white LEDs are an effective solution for enabling intelligent headlights in automotive white LEDs. Considering size and weight, multiple chip-level white LEDs are typically integrated into a matrix. This requires high-power density packaging of individual chip-level white LEDs, with high brightness, high-temperature resistance, and excellent thermal stability.

[0005] Fluorescent ceramics have the advantages of high luminous efficiency, high thermal conductivity, high temperature resistance, and excellent thermal quenching resistance. As fluorescent converters, they solve technical bottlenecks such as heat dissipation difficulties and packaging failure caused by the high power of LEDs. YAG:Ce fluorescent ceramics are a typical representative of them. Its packaged fluorescent ceramic LEDs are widely used as stadium lights, searchlights, fishing lights, etc. Unlike these large-volume lighting fixtures, chip-level white light LEDs tend to develop in a miniaturized manner, which also requires ultra-thin fluorescent ceramics to adapt to chip-level packaging. At the same time, the development of thin fluorescent ceramics faces two technical challenges that need to be solved urgently. First, most studies have shown that the luminous flux and luminous efficiency of fluorescent ceramics decrease with decreasing thickness. For example, the literature (App.Sur.Sci.455(2018)425-432) reported that when the thickness of YAG:Ce fluorescent ceramics is reduced from 1.2mm to 0.2mm, its luminous intensity attenuation is greater than 80%. Secondly, the red light component of the YAG:Ce fluorescent ceramic spectrum is insufficient, and the color coordinates of the white light LED packaged by it deviate from the white light zone. As a car light source, the luminous color should be as close as possible to the midday sunlight (color temperature 5500~6000K). In order to adjust the color coordinates of the YAG:Ce fluorescent ceramic LED, Mg is usually doped in YAG:Ce. 2+ -Si 4+ , Ca 2+ -Si 4+ 、Gd 3+ 、Mn 2+ 、Pr 3+ Plasma modulates the emission spectrum and compensates for the red light component, but this doping also reduces luminous flux and efficacy. Therefore, in order to achieve chip-scale, high-brightness white LEDs, resolving the compatibility issues of thinning fluorescent ceramics, color coordinate white light control, and reduced luminous flux and efficacy has become a pressing technical challenge in this field. Summary of the Invention

[0006] In order to improve the above technical problems, the present invention provides an ultra-thin, high-light-efficiency fluorescent ceramic, a preparation method, and a chip-level white light LED device. The ultra-thin fluorescent ceramic of the present invention is applied to white light LED devices, which not only improves the brightness and packaging power density of the LED devices, but also improves the thermal stability of the LED devices, and obtains high-brightness white light close to midday sunlight (color temperature 5500-6000K), empowering the intelligence of automotive white light LEDs.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a fluorescent ceramic material, the chemical composition of which is Y 3-x-y (Al 1-w A w )2(Al 1-z X z)3O 12 :xCe 3+ ,yR 3+ ,wA 2+ ,zX 4+ ,in:

[0009] A is selected from divalent alkaline earth metal elements; X is selected from tetravalent elements; R is selected from trivalent rare earth elements other than Al and Ce;

[0010] x is rare earth Ce 3+ As the doping amount of the luminescent center ion, y is R 3+ Occupy Y 3+ The doping amount of the bit, w is A 2+ Occupy Al 3+ The doping amount of the bit; z is X 4+ Occupy Al 3+ The doping amount of the bit;

[0011] 0<x≤0.03, 0≤y≤2.0, x+y≤2.0; 0≤w≤1.0, 0≤z≤1.0.

[0012] In the present invention, Y 3-x-y (Al 1-w A w )2(Al 1-z X z )3O 12 In the structure, 1-w is Al occupying Al 1-w A w The doping amount of the octahedral lattice, 1-z is Al occupying Al 1-z X z According to an embodiment of the present invention, R is selected from at least one of Tb, Gd, Tm, and Lu.

[0013] According to an embodiment of the present invention, A is selected from at least one of Ga, Sc, Ca, Ba, and Mg.

[0014] According to an embodiment of the present invention, X is selected from at least one of Si, Hf, Zr and Ge.

[0015] In the present invention, by changing the types and ratios of R, A, and X, the luminescent color of the fluorescent ceramic material can be adjusted within the range of 530 to 560 nm, and the luminescent thermal stability of the fluorescent ceramic material can be made not less than 90% at 200°C, thereby meeting the packaging application requirements of different white light LEDs.

[0016] According to an embodiment of the present invention, Ce 3+ The doping amount is preferably 0.001≤x≤0.01; illustratively, x=0.005, 0.01, 0.02 or 0.03.

[0017] According to an embodiment of the present invention, the doping amount of R is preferably 0.5≤y≤1.0, and illustratively, y=0, 0.01, 0.02, 0.03, 0.05, 0.1, 0.2, 0.5 or 1.

[0018] According to an embodiment of the present invention, the doping amount of A is preferably 0.2≤w≤0.8; illustratively, w=0, 0.01, 0.02, 0.03, 0.05, 0.1, 0.2, 0.25, 0.5 or 0.8.

[0019] According to an embodiment of the present invention, the doping amount of X is preferably 0.2≤z≤0.8; illustratively, z=0, 0.01, 0.02, 0.03, 0.05, 0.1, 0.2, 0.25, 0.5 or 0.8.

[0020] According to an embodiment of the present invention, the fluorescent ceramic material is an ultra-thin fluorescent ceramic. Preferably, the thickness of the fluorescent ceramic material is ≤0.25 mm, preferably ≤0.20 mm, such as 0.10-0.25 mm, exemplified by 0.10 mm, 0.15 mm, 0.20 mm or 0.25 mm.

[0021] According to an embodiment of the present invention, the average grain size of the fluorescent ceramic material is ≤10 μm, exemplified by 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0022] According to an embodiment of the present invention, the peak wavelength of the emission spectrum of the fluorescent ceramic material is 530-560 nm, exemplified by 530 nm, 535 nm, 541 nm, 551 nm or 560 nm.

[0023] According to an embodiment of the present invention, the fluorescent ceramic material is prepared by pressing raw materials including Y source, Al source, A source, X source, R source and Ce source, and then performing debinding, high temperature sintering and annealing.

[0024] The present invention also provides a method for preparing the above-mentioned fluorescent ceramic material, comprising the following steps: pressing and molding raw materials of Y source, Al source, A source, X source, R source and Ce source, and then performing debinding and high-temperature sintering treatments and annealing to prepare the fluorescent ceramic material.

[0025] According to an embodiment of the present invention, the Y source, Al source, A source, X source, R source, and Ce source are respectively provided by oxide powder containing the Y element, oxide powder containing the Al element, oxide powder containing the Ce element, oxide powder containing the R element, oxide powder containing the A element, and oxide powder containing the X element. Preferably, the particle size of the oxide powder is ≤10 μm, preferably ≤5 μm.

[0026] According to an embodiment of the present invention, the press molding further includes a step of ball milling the raw materials. For example, the ball milling time is 15 to 30 hours, preferably 20 to 30 hours, and exemplarily 15 hours, 16 hours, 18 hours, 20 hours, 25 hours, 28 hours, or 30 hours; the ball milling speed is 100 to 1000 r / min, preferably 100 to 400 r / min, and exemplarily 250 r / min or 300 r / min.

[0027] According to an embodiment of the present invention, the debinding temperature is 600-1000°C, exemplified by 600°C, 700°C, 800°C, 900°C or 1000°C; the debinding holding time is 3-10h, exemplified by 3h, 6h, 8h or 10h.

[0028] According to an embodiment of the present invention, the temperature of the high-temperature sintering is 1500-1800°C, exemplified by 1500°C, 1650°C, 1700°C, 1750°C or 1800°C; the time of the high-temperature sintering is 3-20h, preferably 5-10h, exemplified by 3h, 5h, 6h, 8h, 10h or 15h.

[0029] According to an embodiment of the present invention, during the high-temperature sintering process, the temperature is rapidly increased from 1400°C to the holding temperature stage to control grain growth and inhibit pore removal, so as to obtain a fluorescent ceramic material with an average grain size of ≤10μm. For example, the heating rate is not less than 6°C / min, preferably not less than 10°C / min, such as 6-20°C / min or 10-15°C / min, exemplified by 10°C / min, 15°C / min or 20°C / min. The present invention does not specifically limit the heating rate before 1400°C during the high-temperature sintering process, for example, it can be 5-10°C / min; after the temperature is raised to 1400°C, the heating rate of not less than 6°C / min is used to control the grain size to avoid excessive grain size.

[0030] According to an embodiment of the present invention, the annealing is performed in an oxygen-containing atmosphere. For example, the annealing temperature is 1000-1400°C, exemplified by 1000°C, 1100°C, 1200°C, 1300°C, or 1400°C; and the annealing time is 3-10 hours, exemplified by 3 hours, 5 hours, 6 hours, 8 hours, or 10 hours.

[0031] According to an embodiment of the present invention, the preparation method may further include grinding the fluorescent ceramic material, for example, grinding the ceramic material to a thickness of ≤0.25 mm, preferably ≤0.20 mm.

[0032] According to an embodiment of the present invention, the preparation method may further include cutting the fluorescent ceramic material to obtain chip-level fluorescent ceramic products. For example, the cutting size of the fluorescent ceramic is controlled to be ≤2 mm×2 mm, preferably ≤1 mm×1 mm.

[0033] According to an embodiment of the present invention, the method for preparing the fluorescent ceramic material comprises the following steps:

[0034] (1) Ball milling: according to the designed chemical formula Y 3-x-y (Al 1-w A w )2(Al 1-z X z )3O 12 :xCe 3+ ,yR 3+ ,wA 2+ ,zX 4+ Weigh oxide powders containing Y source, Al source, Ce source, R source, A source and X source and ball mill them;

[0035] (2) Powder processing: The slurry obtained by ball milling is dried and sieved to obtain ceramic powder;

[0036] (3) Body forming: The ceramic powder is pressed and formed, and then the binder is removed to obtain a ceramic green body; the binder removal temperature is controlled to be 600-1000°C, and the holding time is 3-10 hours;

[0037] (4) Ceramic sintering: The green body is sintered at high temperature to obtain fluorescent ceramics; the sintering temperature is controlled to be 1500-1800°C and the holding time is 3-20h;

[0038] (5) Ceramic annealing: The fluorescent ceramic is placed in an oxygen-containing atmosphere for high-temperature annealing to eliminate oxygen vacancy defects and residual stress; the annealing temperature is controlled at 1000-1400°C and the holding time is 3-10 hours;

[0039] (6) Grinding: Grinding and cutting the fluorescent ceramic to obtain chip-level fluorescent ceramic products; controlling the thickness of the fluorescent ceramic to be ≤0.25 mm, preferably ≤0.20 mm; controlling the cutting size of the fluorescent ceramic to be ≤2 mm×2 mm, preferably ≤1 mm×1 mm.

[0040] The present invention also provides applications of the aforementioned fluorescent ceramic materials in LEDs. Preferably, the materials are used in lighting and display applications such as high-brightness white light illumination and micro-projection. For example, they are used in white LEDs for smart cars and smart cockpits, particularly in matrix-type white LEDs for use in vehicles.

[0041] The present invention also provides an LED device, which contains the fluorescent ceramic material.

[0042] According to an embodiment of the present invention, the LED device is a chip-scale white light LED device.

[0043] According to an embodiment of the present invention, the LED device further comprises a heat dissipation aluminum substrate and a blue light chip. Preferably, the LED device is manufactured using a COB packaging method.

[0044] According to an embodiment of the present invention, the emission wavelength of the blue light chip is 450-470 nm, preferably 455-465 nm, and exemplified as 460 nm.

[0045] According to the embodiment of the present invention, the packaging power density of the LED device is not less than 10W / mm 2 , preferably not less than 8W / mm 2 .

[0046] According to an embodiment of the present invention, the luminous flux of the LED device is not less than 1100 lm, preferably not less than 1300 lm; exemplary values ​​are 1100 lm, 1158 lm, 1230 lm or 1350 lm.

[0047] According to an embodiment of the present invention, the color temperature of the LED device is adjustable within a range of 5000-6000K, with exemplary colors being 5000K, 5100K, 5200K, 5300K, 5400K, 5534K, 5734K, 5854K or 6000K.

[0048] According to an embodiment of the present invention, the color coordinates of the LED device are CIE-X=0.29~0.35, exemplified by 0.29, 0.30, 0.3125, 0.3138, 0.3273, 0.33, 0.34 or 0.35; CIE-Y=0.29~0.35, exemplified by 0.29, 0.30, 0.31, 0.3265, 0.3369 or 0.3457.

[0049] According to an embodiment of the present invention, the LED device is an ultra-thin fluorescent ceramic white light LED device. For example, the light emitting surface of the LED device is ≤2 mm×2 mm, preferably ≤1 mm×1 mm.

[0050] Compared with the existing technical solutions, the present invention has the following beneficial effects:

[0051] (1) The fluorescent ceramic of the present invention has the characteristics of high temperature resistance, acid and alkali resistance, and high thermal stability of luminescence, which avoids the technical deficiencies of white light LED packaging failure and heat dissipation difficulties, and can be applied to high power density packaging of white light LEDs, effectively improving the service life of the device;

[0052] (2) The fluorescent ceramics of the present invention solve the compatibility problem between ultra-thin thickness of fluorescent ceramics and high brightness and white light regulation. The luminous flux of the chip-level white light LED packaged therein is not less than 1300lm, and the color coordinates are adjustable in the range of CIE-X=0.29~0.35 and CIE-Y=0.29~0.35. It has broad application prospects in the field of high-brightness white light lighting, especially for enabling the intelligentization of automotive matrix LED white light. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] FIG1 is a microscopic morphology of the fluorescent ceramic in Example 1 (scale 200 μm).

[0054] FIG2 is a photoluminescence spectrum of the fluorescent ceramic in Example 1.

[0055] FIG3 is a graph showing the thermal quenching performance of the fluorescent ceramic in Example 1.

[0056] FIG4 is a diagram showing the packaging structure of a fluorescent ceramic LED device.

[0057] FIG5 is an electroluminescence spectrum of the fluorescent ceramic in Example 1.

[0058] FIG6 is a photoluminescence spectrum of the fluorescent ceramic in Comparative Example 1. DETAILED DESCRIPTION

[0059] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative 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 encompassed within the scope of protection that the present invention is intended to protect.

[0060] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0061] Example 1

[0062] According to the stoichiometric ratio Y 1.99 Al2Al3O 12 :0.01Ce 3+ ,1Gd 3+ (YGdAG:Ce) was prepared by weighing Y2O3 6.783g, Al2O3 7.695g, CeO2 0.052g and Gd2O3 5.472g in order. 50<5μm) raw material powder is subjected to planetary ball milling for 25 hours at a rotation speed of 250r / min to obtain a refined and uniformly mixed powder; the powder is then pressed into a ceramic blank; the blank is subjected to binder removal at 600°C for 6 hours, and then placed in a vacuum tungsten wire furnace for high-temperature sintering, wherein the temperature is raised to 1400°C and then to 1650°C at a heating rate of 10°C / min, and then sintered at high temperature for 5 hours; and then annealed at 1300°C for 5 hours to obtain a fluorescent ceramic; the fluorescent ceramic is ground to a thickness of 0.2mm and then cut into 1mm×1mm pieces to obtain a fluorescent ceramic product.

[0063] As shown in Figure 1, the fluorescent ceramic produced in this example exhibits a dense microstructure, no pores, and highly uniform luminescence under a fluorescence microscope. Under 460nm blue light excitation, the fluorescent ceramic emits yellow light with a peak wavelength of 551nm (Figure 2). The luminescence intensity decays by only 11.2% at 200°C, demonstrating excellent performance with high brightness and thermal stability (Figure 3).

[0064] As shown in the enlarged view of FIG4 , a chip-level high-power-density white light LED light source (luminous surface 1 mm×1 mm) packaged in a fluorescent ceramic is formed by encapsulating the YGdAG:Ce fluorescent ceramic product prepared in this embodiment with a 450nm blue light LED chip. Under 10W electric power excitation, the luminous spectrum ( FIG5 ) and light color properties of the LED light source tested at room temperature are: CIE-X = 0.3273, CIE-Y = 0.3369, color temperature 5734K, color rendering index 70, luminous flux 1230 lm, and luminous efficiency 125.3 lm / W, demonstrating high-brightness white light and high thermal stability.

[0065] Example 2

[0066] According to the stoichiometric ratio Y 2.99 Al 1.75 Al 2.25 O 12 :0.01Ce 3+ ,0.25Mg 2+ ,0.25Si 4+ (YMASG:Ce) fluorescent ceramics were prepared. The preparation process parameters were the same as in Example 1. Y2O3 11.398g, Al2O3 6.444g, CeO2 0.029g, MgO 0.679g and SiO2 1.012g were weighed in sequence. 50<5μm) raw material powder is subjected to planetary ball milling for 25 hours at a rotation speed of 250r / min to obtain a refined and uniformly mixed powder; the powder is then pressed into a ceramic blank; the blank is subjected to debinding at 600°C for 6 hours, and then placed in a vacuum tungsten wire furnace for high-temperature sintering, wherein the temperature is increased from 1400°C to 1650°C at a heating rate of 10°C / min and held at high temperature for 5 hours; and then annealed at 1300°C for 5 hours to obtain a fluorescent ceramic; the fluorescent ceramic is ground to a thickness of 0.2mm and then cut into 1mm×1mm pieces to obtain a fluorescent ceramic product.

[0067] Under the excitation of 460nm blue light, the fluorescent ceramic prepared in this embodiment emits yellow light with a peak wavelength of 545nm, and the luminous intensity at 200°C is only attenuated by 8.2%, showing excellent performance of high brightness and high thermal stability.

[0068] A fluorescent ceramic-packaged chip-level high-power density white light LED light source (light-emitting surface 1 mm×1 mm) is packaged with the YMASG:Ce fluorescent ceramic product prepared in this example and a 450nm blue light LED chip. Under 20W electric power excitation, the light color performance of the LED light source tested at room temperature is: CIE-X=0.3125, CIE-Y=0.3457, color temperature 5534K, color rendering index 70, luminous flux 1158lm, and luminous efficiency 57.9lm / W, showing high-brightness white light and high thermal stability.

[0069] Example 3

[0070] According to the stoichiometric ratio Y 2.995 Al2Al3O 12 :0.005Ce 3+ (YAG:Ce) was prepared, and Y2O3 11.388g, Al2O3 8.584g and CeO2 0.029g were weighed in sequence. 50 <5μm) raw material powder is planetarily ball milled for 16 hours at a rotation speed of 300r / min to obtain a refined and uniformly mixed powder; the powder is then pressed to obtain a ceramic green body; the green body is subjected to binder removal at 800°C for 8 hours, and then placed in a vacuum tungsten wire furnace for high-temperature sintering, wherein the temperature is increased from 1400°C to 1750°C at a heating rate of 10°C / min and held at high temperature for 5 hours; and then annealed at 1300°C for 5 hours to obtain a fluorescent ceramic; the fluorescent ceramic is ground to a thickness of 0.2mm and then cut into pieces of 1.5mm×1.5mm to obtain a YAG:Ce ceramic fluorescent ceramic product.

[0071] Under 460nm blue light excitation, YAG:Ce ceramics emit yellow light with a peak wavelength of 541nm, and the luminous intensity at 200℃ only decays by 9.2%, showing excellent performance of high brightness and high thermal stability.

[0072] A fluorescent ceramic-packaged chip-level high-power density white light LED light source (light-emitting surface 1.5 mm×1.5 mm) is packaged with the YAG:Ce fluorescent ceramic product prepared in this example and a 450nm blue light LED chip. Under 20W electric power excitation, the light color performance of the LED light source tested at room temperature is: CIE-X=0.3138, CIE-Y=0.3265, color temperature 5854K, color rendering index 71, luminous flux 1350lm, and luminous efficiency 65.2lm / W, showing high-brightness white light and high thermal stability.

[0073] Comparative Example 1

[0074] According to the stoichiometric ratio Y 2.994 Al2Al3O 12 :0.001Ce 3+ ,0.005Pr 3+ The ingredients were weighed in sequence: Y2O3 11.299g, Al2O3 8.555g, CeO2 0.017g and Pr6O 11 0.085g equal micron (D 50 <5 μm) raw material powder to prepare YAG:Ce,Pr fluorescent ceramic products. The remaining preparation processes and parameters are the same as those in Example 1.

[0075] Under 460nm blue light excitation, Ce 3+ and Pr 3+ The fluorescent ceramic prepared in this comparative example emits synergistic luminescence, with peak wavelengths of 525 nm and 610 nm (as shown in FIG6 ), and the luminescence intensity attenuates by 15.7% at 200° C.

[0076] A fluorescent ceramic packaged chip-level high-power density white LED light source (light-emitting surface 1mm×1mm) is packaged with the YAG:Ce,Pr fluorescent ceramic product prepared in this comparative example and a 450nm blue LED chip. Under 20W electric power excitation, the light color performance of the LED light source is tested at room temperature and is as follows: CIE-X=0.4502, CIE-Y=0.4383, color temperature 5834K, color rendering index 67, luminous flux 1028lm, and luminous efficiency 51.4lm / W. It can be seen that due to Ce 3+ and Pr 3+ There is energy transfer, which causes the brightness of the fluorescent ceramic to be lower than that of Example 1, and the coordinates of the white light LED light source are shifted to the white light region, thus failing to meet the requirements of positive white light.

[0077] Comparative Example 2

[0078] YMASG:Ce fluorescent ceramic products were prepared according to the formula and process parameters of Example 2. The difference from Example 2 was that the heating rate from 1400°C to 1650°C was 2°C / min, and the other conditions were the same as Example 2.

[0079] Under the excitation of 460nm blue light, the fluorescent ceramic emits yellow light with a peak wavelength of 543nm, and the luminous intensity decays by 10.2% at 200℃.

[0080] A fluorescent ceramic-encapsulated chip-scale high-power density white LED light source (1mm×1mm luminous surface) is constructed from the YMASG:Ce fluorescent ceramic product prepared in this comparative example and encapsulated with a 450nm blue LED chip. Under 20W excitation, the LED light source's colorimetric performance at room temperature is as follows: CIE-X = 0.3238, CIE-Y = 0.3524, color temperature 5734K, color rendering index 68, luminous flux 1058lm, and luminous efficacy 52.9lm / W. In this comparative example, the heating rate from 1400°C to 1650°C is lower than that in Example 2, resulting in significantly larger grain sizes. Consequently, the thermal quenching performance and brightness of the LED light source are significantly lower than those in Example 2.

[0081] Comparative Example 3

[0082] According to the stoichiometric ratio Y 2.95 Al2Al3O 12 :0.05Ce 3+ The ingredients were weighed in turn, and Y2O3 11.174g, Al2O3 8.551g and CeO2 0.289g were weighed in order. 50 <5 μm) raw material powder to prepare ultra-thin YAG:Ce fluorescent ceramic products. The remaining preparation processes and parameters are the same as those in Example 3.

[0083] Under 460nm blue light excitation, YAG:Ce ceramics emit yellow light with a peak wavelength of 553nm, and the luminous intensity decays by 10.1% at 200℃.

[0084] A chip-scale, high-power-density white LED light source (1.5 mm x 1.5 mm luminous surface) encapsulated with a fluorescent ceramic package is constructed from the YAG:Ce fluorescent ceramic product prepared in this comparative example and a 450 nm blue LED chip. Under 20 W excitation, the LED light source's color performance at room temperature was tested to be: CIE-X = 0.4325, CIE-Y = 0.5057, color temperature 6234 K, color rendering index 64, luminous flux 1368 lm, and luminous efficacy 68.4 lm / W. This indicates that increasing the Ce content shifts the coordinates of the white LED light source into the white light region, failing to meet the requirements for true white light.

[0085] The above description is only a preferred specific embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any technical personnel familiar with the technical field, within the technical scope disclosed by the present invention, shall make modifications, equivalent replacements, improvements, etc. based on the technical solution and inventive concept of the present invention, and all such modifications shall be included in the scope of protection of the present invention.

Claims

1. A fluorescent ceramic material, characterized in that: Its chemical composition is Y 3-x-y (Al 1-w A w )2(Al 1- z X z )3O 12 :xCe 3+ ,yR 3+ ,wA 2+ ,zX 4+ , wherein: A is selected from divalent alkaline earth metal elements; X is selected from tetravalent elements; R is selected from trivalent rare earth elements other than Al and Ce; x is rare earth Ce 3+ As the doping amount of the luminescent center ion, y is R 3+ Occupy Y 3+ The doping amount of the bit, w is A 2+ Occupy Al 3+ The doping amount of the bit; z is X 4+ Occupy Al 3+ The doping amount of the bit; 0<x≤0.03, 0≤y≤2.0, x+y≤2.0; 0≤w≤1.0, 0≤z≤1.

0.

2. The fluorescent ceramic material according to claim 1, wherein R is selected from at least one of Tb, Gd, Tm, and Lu; and / or, A is selected from at least one of Ga, Sc, Ca, Ba and Mg; and / or, X is selected from at least one of Si, Hf, Zr and Ge; And / or, the thickness of the fluorescent ceramic is ≤0.25 mm; and / or, the average grain size of the fluorescent ceramic material is ≤10 μm; And / or, the peak wavelength of the emission spectrum of the fluorescent ceramic material is 530-560 nm.

3. The fluorescent ceramic material according to claim 1 or 2, characterized in that: The fluorescent ceramic material is prepared by pressing raw materials including a Y source, an Al source, an A source, an X source, an R source and a Ce source into a shape, and then performing debinding, high-temperature sintering and annealing.

4. The method for preparing the fluorescent ceramic material according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: pressing raw materials of Y source, Al source, A source, X source, R source and Ce source into shape, and then subjecting them to debinding, high-temperature sintering and annealing to prepare the fluorescent ceramic material.

5. The preparation method according to claim 4, wherein The Y source, Al source, A source, X source, R source and Ce source are respectively provided by oxide powder containing Y element, oxide powder of Al element, oxide powder of Ce element, oxide powder of R element, oxide powder of A element and oxide powder of X element.

6. The preparation method according to claim 4, wherein The debinding temperature is 600-1000°C; the debinding holding time is 3-10h; And / or, the temperature of the high temperature sintering is 1500-1800° C.; the time of the high temperature sintering is 3-20 hours; And / or, during the high-temperature sintering process, the temperature is rapidly increased from 1400° C. to the holding temperature, with a heating rate of not less than 6° C. / min.

7. The preparation method according to any one of claims 4 to 6, characterized in that The preparation method of the fluorescent ceramic material comprises the following steps: (1) Ball milling: according to the designed chemical formula Y 3-x-y (Al 1-w A w )2(Al 1-z X z )3O 12 :xCe 3+ ,yR 3+ ,wA 2+ ,zX 4+ Weigh oxide powders containing Y source, Al source, Ce source, R source, A source and X source and ball mill them; (2) Powder processing: The slurry obtained by ball milling is dried and sieved to obtain ceramic powder; (3) Body forming: The ceramic powder is pressed and formed, and then the binder is removed to obtain a ceramic green body; the binder removal temperature is controlled to be 600-1000°C, and the holding time is 3-10 hours; (4) Ceramic sintering: The green body is sintered at high temperature to obtain fluorescent ceramics; the sintering temperature is controlled to be 1500-1800°C and the holding time is 3-20h; (5) Ceramic annealing: The fluorescent ceramic is placed in an oxygen-containing atmosphere for high-temperature annealing, with the annealing temperature controlled at 1000-1400°C and the holding time at 3-10 hours; (6) Grinding: Grind and cut fluorescent ceramics to obtain chip-level fluorescent ceramic products.

8. Use of the fluorescent ceramic material according to any one of claims 1 to 3 in LEDs.

9. An LED device, characterized in that: The fluorescent ceramic material contains the fluorescent ceramic material according to any one of claims 1 to 3.

10. The LED device according to claim 9, wherein The LED device further includes a heat dissipation aluminum substrate and a blue light chip; preferably, the LED device is a white light LED device.

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