Light scattering enhanced ultra-thin fluorescent ceramic, preparation method thereof and LED device

Abstract

The application discloses a light scattering enhanced ultra-thin fluorescent ceramic and a preparation method thereof and an LED device thereof, and the chemical formula of the fluorescent ceramic is A-Y 3‑x‑y Al 5‑2z O 12 :xCe 3+ ,yE 3+ ,zM 2+ ,zX 4+ ; wherein: x is the doping amount of Ce 3+ light emitting center, y is the doping amount of E 3+ occupying Y 3+ site, and z is the doping amount of M 2+ and X 4+ occupying Al 3+ site; 0.0<=x<=0.3; 0.0<=y<=3.0; 0.0<=z<=0.5, and x+y<=3.0. The fluorescent ceramic has the characteristics of adjustable light emission spectrum in 500-700 nm, ultra-thin thickness (<=0.5 mm), high light efficiency and high thermal stability, and the packaged LED device has the advantages of small volume, long service life and high light intensity, and is suitable for the illumination and display fields such as automobile headlamps, augmented reality head-up display (AR-HUD) and micro projection.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent ceramic materials and LED devices, and in particular relates to a light scattering enhanced ultrathin fluorescent ceramic material, its preparation method and LED device. Background Technology

[0002] With the arrival of the era of intelligent vehicles, the demand for lighting and displays such as automotive headlights, augmented reality head-up displays (AR-HUD), and micro-projectors has surged, bringing explosive growth opportunities to small-sized LED light source devices such as high-power-density miniLEDs and chip-level LEDs. Currently, these small-sized LEDs face challenges such as low luminous flux / efficiency and excessive heat generation in high-power-density applications. Traditional phosphor adhesives or fluorescent glass, due to their low thermal conductivity, easily cause technical bottlenecks such as "difficult heat dissipation" and "encapsulation failure" when LEDs are used for high power. Fluorescent ceramics possess inherent advantages such as high temperature resistance, high thermal conductivity, and good physicochemical properties, while also offering modification potential for light transmission, light emission, and dimming. Using them for encapsulating high-power-density small-sized LED devices can effectively solve problems such as high heat generation and difficult heat dissipation, thereby improving device stability and lifespan.

[0003] To match the small-size LED packaging, the phosphor ceramic should have an ultra-thin thickness. Furthermore, Y3Al5O is used for high-power LED packaging in the hundreds of watts / kilowatts range. 12 :Ce 3+ (YAG:Ce)-based fluorescent ceramics are relatively thick (>1 mm), resulting in high material costs and low utilization rates. Reducing their thickness is an effective way to reduce costs and increase efficiency. Currently, fluorescent ceramics generally suffer from a decrease in luminous flux / luminous efficacy as thickness decreases, thus limiting the widespread application of high-brightness, small-size fluorescent ceramic LEDs. For example, existing technologies ( Applied Physics Lett. 101(2021) 061902) reported that when the thickness of the YAG:Ce fluorescent ceramic was reduced from 1.0 mm to 0.1 mm, the luminous efficacy decreased sharply from 82 lm / W to 41 lm / W; and existing technologies ( App. Sur. Sci. 455(2018)425-432) reported that when the thickness of the YAG:Ce fluorescent ceramic was reduced from 1.2 mm to 0.2 mm, the luminescence intensity decreased by more than 80%; existing technologies ( J. Mater. Chem. C Studies (7(2019) 11449-11456) have shown that when the thickness of YAG:Ce fluorescent ceramics is reduced, not only is the luminous flux decreased, but the saturation threshold also decreases from 31.90 W / mm². -2 Reduced to 25.98 mm -2 Current research on fluorescent ceramics rarely focuses on improving the luminous efficacy of ultrathin fluorescent ceramics. For example, existing technologies (…) J. Adv. Ceram.,(2023, 12(2), 625-633.) reported LuAG:Ce-Al2O3 multiphase ceramics, which enhanced the luminous efficacy of the multiphase ceramics to 155.0 lm / W based on the light scattering effect of Al2O3, but the thickness of the multiphase ceramics was as high as 1.0 mm; and the existing technology ( Adv. Opt. Mater. A study (2021, 2002141) reported a 2.0 mm thick LuAG:Ce+Ba / Si green light ceramic with a luminous efficacy of 216.9 lm / W. However, considering the thickness-induced attenuation effect of phosphor ceramics, the luminous efficacy of these thick phosphor ceramics is insufficient to meet the packaging requirements of high-brightness, small-size LEDs.

[0004] Therefore, there is an urgent need in the market for a small-sized LED device with high brightness and high thermal stability to improve the working life, stability and color performance of applications such as automotive headlights, AR-HUDs, and micro-projectors. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a high-efficiency ultrathin fluorescent ceramic material, its preparation method, and an LED device. The LED device has numerous advantages, including small size, high luminous efficiency, and long lifespan.

[0006] This invention provides a fluorescent ceramic material with the chemical composition AY. 3-x-y Al 5-2z O 12 : x Ce 3+ , y E 3+ , z M 2+ , z X 4+ ;in: x For Ce 3+ Doping level of luminescent centers y For E 3+ Occupy G 3+ The doping amount of the bit, z For M 2+ X 4+ Occupy Al 3+ Doping level of the bit; 0.0≤ x ≤0.3; 0.0≤ y ≤3.0; 0.0≤ z ≤0.5, and x + y ≤3.0;

[0007] A is the light scattering enhancement phase; E, M, and X are dopants that play a role in spectral modulation; X and M are introduced simultaneously as ion pairs to balance the charge.

[0008] According to an embodiment of the present invention, 0.0 ≤ x ≤0.3; preferably 0.01≤ x ≤0.1, more preferably 0.02≤ x ≤0.05; for example, x =0.005, 0.01, 0.02, 0.03, 0.05, 0.1, 0.2, 0.3.

[0009] According to an embodiment of the present invention, 0.0 ≤ y ≤3.0, preferably 0.1≤ y ≤2; more preferably 2≤ y ≤3; for example, y =0, 0.01, 0.1, 0.2, 0.5, 1, 1.5, 2, 2.5, 2.98, 2.99, 3.0.

[0010] According to an embodiment of the present invention, 0.0 ≤ z ≤0.5, preferably 0.01≤ z ≤0.3, more preferably 0.05≤ z ≤0.1; for example, z =0, 0.005, 0.01, 0.02, 0.03, 0.4, 0.5.

[0011] According to an embodiment of the present invention, the fluorescent ceramic material comprises a light scattering enhancement phase A and a main phase Y. 3-x-y Al 5- 2z O 12 : x Ce 3+ , y E 3+ , z M 2+ , z X 4+ Composition. Preferably, based on the total weight of the fluorescent ceramic material, the mass percentage of the light scattering enhancement phase A is 1-50 wt%, more preferably 3-30 wt%, more preferably 5-20 wt%, with exemplary values ​​of 1 wt%, 3 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 30 wt%, 40 wt%, and 50 wt%.

[0012] According to an embodiment of the present invention, the light scattering enhancement phase A is selected from at least one of Al2O3, Y2O3, Lu2O3, MgAl2O4, BaAl2O4 and MgO.

[0013] According to an embodiment of the present invention, the average grain size of the light scattering enhancement phase A is less than 10 μm, preferably less than 5 μm, more preferably less than 1 μm, for example 10 nm to 1 μm, and exemplary values ​​are 40 nm, 60 nm, 100 nm, and 1 μm.

[0014] According to an embodiment of the present invention, E is selected from at least one of Lu, Ga, Sc, Pr, Tb, Gd, Eu, and Sm.

[0015] According to an embodiment of the present invention, M is selected from at least one of Mg, Ca, Sr, Ba and Mn.

[0016] According to an embodiment of the present invention, X is selected from at least one of Si, Zr, Ti and Ge.

[0017] According to an embodiment of the present invention, the fluorescent ceramic material is prepared by reacting raw materials including Y source, Al source, E source, M source, X source and Ce source at high temperature with a solid phase, adding light scattering enhancement phase A, pressing and molding, and then debinding and high temperature sintering.

[0018] According to an embodiment of the present invention, the fluorescent ceramic material is an ultrathin fluorescent ceramic material. Preferably, the thickness of the fluorescent ceramic material is ≤0.5 mm, more preferably ≤0.25 mm, for example 0.10-0.40 mm, and exemplary thicknesses are 0.15 mm, 0.25 mm, 0.30 mm, and 0.40 mm.

[0019] In this invention, by changing the types and / or contents of E, M, and X, the emission spectrum of the fluorescent ceramic material can be adjusted in the range of 500~700nm.

[0020] According to an embodiment of the present invention, the peak wavelength of the emission spectrum of the fluorescent ceramic material is 500~700nm, preferably 520~600nm, and exemplary wavelengths are 525nm, 530nm, 535nm, 540nm, 545nm, 550nm, 560nm, 570nm, 580nm, 590nm, and 600nm.

[0021] According to an embodiment of the present invention, the fluorescent ceramic material, when excited by a blue LED chip, has a luminous efficacy of not less than 100 lm / W, preferably not less than 150 lm / W, more preferably not less than 190 lm / W, for example, 113.2~211.0 lm / W, with exemplary values ​​of 113.2 lm / W, 145.3 lm / W, 184.1 lm / W, 202.5 lm / W, and 204.7 lm / W.

[0022] According to an embodiment of the present invention, the luminous flux of the fluorescent ceramic material is 5000~11100 lm, with exemplary values ​​of 5650 lm, 7264 lm, 9203 lm, 10150 lm, and 10198.0 lm.

[0023] The present invention also provides a method for preparing the above-mentioned fluorescent ceramic material, comprising the following steps: after subjecting raw materials including Y source, Al source, E source, M source, X source and Ce source to a high-temperature solid-state reaction, adding light scattering enhancement phase A, pressing and molding, and then debinding and high-temperature sintering treatment to obtain the material.

[0024] According to an embodiment of the present invention, the Y source is provided by a compound containing the element Y; for example, it is provided by at least one of oxides, hydroxides, carbonates, chlorides and nitrates containing the element Y; preferably, it is provided by an oxide containing the element Y.

[0025] According to an embodiment of the invention, the Al source is provided by an Al-containing compound; for example, by at least one of an Al-containing oxide, hydroxide, carbonate, chloride, and nitrate; preferably by an Al-containing oxide.

[0026] According to an embodiment of the present invention, the E source is provided by a compound containing element E; for example, it is provided by at least one of oxides, hydroxides, carbonates, chlorides and nitrates containing element E; preferably, it is provided by an oxide containing element E.

[0027] According to an embodiment of the invention, the M source is provided by a compound containing the M element; for example, it is provided by at least one of oxides, hydroxides, carbonates, chlorides, and nitrates containing the M element; preferably, it is provided by an oxide containing the M element.

[0028] According to an embodiment of the invention, the X source is provided by a compound containing the X element; for example, by at least one of oxides, hydroxides, carbonates, chlorides, and nitrates containing the X element; preferably by an oxide containing the X element.

[0029] According to an embodiment of the present invention, the Ce source is provided by a compound containing Ce; for example, the compound containing Ce is selected from at least one of CeO2, CeCl3, Ce(SO4)2•4H2O, and Ce(NO3)3•6H2O; preferably CeO2.

[0030] According to an embodiment of the present invention, the powder particle size of the light scattering enhancement phase A is less than 5 μm, preferably less than 1 μm, for example 10 nm to 1 μm, and exemplary particles are 40 nm, 60 nm, 100 nm, and 1 μm.

[0031] According to an embodiment of the present invention, the process further includes a ball milling step of the raw materials before the high-temperature solid-phase reaction. For example, the ball milling time is 15-30 h, preferably 18-24 h, and exemplary times are 15 h, 18 h, 20 h, 24 h, 28 h, and 30 h.

[0032] According to an embodiment of the present invention, the high-temperature solid-phase reaction is carried out under a reducing atmosphere. For example, the reducing atmosphere is an N2-H2 mixture or an N2-CO mixture. Preferably, the volume fraction of H2 or CO is not higher than 10 vol%, more preferably not higher than 5 vol%. Preferably, the volume ratio of N2 to H2 in the N2-H2 mixture is (80~95):(20~5); preferably, the volume ratio of N2 to CO in the N2-CO mixture is (80~95):(20~5); more preferably, the reducing atmosphere is an N2-H2 mixture, and the volume ratio of N2 to H2 is (85~95):(15~5), exemplarily 85:15, 90:10, 95:5.

[0033] According to an embodiment of the present invention, the temperature of the high-temperature solid-phase reaction is 1200~1600 ℃, preferably 1300~1500 ℃, and exemplary values ​​are 1200 ℃, 1300 ℃, 1350 ℃, 1450 ℃, 1500 ℃, and 1600 ℃; the reaction time is 4~10 h, preferably 6~8 h, and exemplary values ​​are 4 h, 6 h, 8 h, and 10 h.

[0034] In this invention, E and MX are dopants that occupy Y or Al lattice sites and are one of the components of ceramics, playing a role in spectral modulation. They are introduced during the ball milling mixing process and, after high-temperature solid-state reaction sintering, enter the ceramic lattice to synthesize phosphors. The phosphors, as the luminescent functional units of fluorescent ceramics, are one of the components of ceramics. The reinforcing phase of this invention is dispersed in the phosphor units to form a multiphase ceramic.

[0035] According to an embodiment of the present invention, the step of ball milling the raw material is further included before the pressing and molding. For example, the ball milling time is 15-30 h, preferably 18-24 h, and exemplary times are 15 h, 18 h, 20 h, 24 h, 28 h, and 30 h.

[0036] According to an embodiment of the present invention, the temperature for discharging the adhesive is 400~1000 ℃, preferably 600~800 ℃, and exemplary values ​​are 400 ℃, 600 ℃, 700 ℃, 800 ℃, and 1000 ℃; the reaction time for discharging the adhesive is 4~10 h, preferably 6~8 h, and exemplary values ​​are 4 h, 6 h, 8 h, and 10 h.

[0037] According to an embodiment of the present invention, the high-temperature sintering temperature is 1300~1800 ℃, preferably 1500~1700 ℃, and exemplary values ​​are 1300 ℃, 1500 ℃, 1750 ℃, and 1800 ℃; the high-temperature sintering time is 3~15 h, preferably 5~10 h, and exemplary values ​​are 3 h, 5 h, 6 h, 8 h, 10 h, and 15 h.

[0038] According to the technical solution of the present invention, the preparation method of the fluorescent ceramic material includes the following steps:

[0039] (1) Ball milling and mixing: with the main phase chemical formula Y 3-x-y Al 5-2z O 12 : x Ce 3+ , y E 3+ , z M 2+ , z X 4+ Weigh out the Y source, Al source, E source, M source, X source and Ce source, and perform ball milling;

[0040] (2) Synthesis of phosphor: The ball-milled powder from step (1) is subjected to a high-temperature solid-phase reaction in a reducing atmosphere;

[0041] (3) Introducing light scattering enhancement phase A: Add light scattering enhancement phase A to the phosphor in step (2) and perform secondary ball milling;

[0042] (4) Green body forming: After pressing the mixed powder from step (3) into shape, the binder is removed to obtain a ceramic green body;

[0043] (5) Ceramic sintering: The green body from step (4) is sintered at high temperature to obtain fluorescent ceramic material;

[0044] (6) Grinding: The fluorescent ceramic material is mechanically processed to an ultra-thin thickness to obtain ceramic products.

[0045] This invention also provides the application of the above-mentioned fluorescent ceramic material in LEDs, preferably in small-size LED light source devices such as high-power miniLEDs and chip-scale LEDs. For example, it can be used as an LED packaging material.

[0046] The present invention also provides a fluorescent ceramic LED device comprising the above-mentioned fluorescent ceramic material.

[0047] According to an embodiment of the present invention, the size of the fluorescent ceramic material in the LED device is, for example, 1 mm × 1 mm.

[0048] According to an embodiment of the present invention, the LED device is an LED lighting or display device, preferably a small-sized LED light source device such as a high-power miniLED or a chip-level LED.

[0049] According to an embodiment of the present invention, the LED device further includes a blue LED chip excitation light source.

[0050] Preferably, the fluorescent ceramic LED device has a peak emission wavelength of 500~530 nm and a luminous efficacy of not less than 190 lm / W.

[0051] Preferably, the fluorescent ceramic LED device has a peak emission wavelength of 530~560 nm and a luminous efficacy of not less than 150 lm / W.

[0052] Preferably, the fluorescent ceramic LED device has a peak emission wavelength of 560~590 nm and a luminous efficacy of not less than 100 lm / W.

[0053] Preferably, the LED lighting or display device is an automotive headlight or an AR-HUD light source.

[0054] The beneficial effects of this invention are:

[0055] (1) The fluorescent ceramic material of the present invention is composed of a main phase and a reinforcing phase. It is an ultrathin fluorescent ceramic material. The reinforcing phase is diffusely distributed and uniformly covers the main phase, increasing the number of grain boundaries, which is conducive to creating a grain boundary light scattering effect to extend the photoluminescence path and enhance the light effect. Moreover, the high thermal conductivity of the reinforcing phase can also synergistically improve the heat dissipation performance of the material.

[0056] (2) The fluorescent ceramic material prepared by the present invention achieves compatibility between ultra-thin thickness and high luminous efficacy. Under the condition of obtaining the same luminous efficacy of 200.0-210.0 lm / W, the thickness of the fluorescent ceramic material is as thin as 0.10-0.25 mm, which is beneficial to reduce the amount of fluorescent ceramic used and the corresponding cost.

[0057] (3) The ultra-thin fluorescent ceramic material prepared by the present invention is suitable for packaging small-volume LED devices, enabling high-power-density lighting and display devices such as automotive headlights, AR-HUD, and micro-projectors to achieve high luminous uniformity, higher light intensity, higher reliability, and longer service life. Attached Figure Description

[0058] Figure 1 This is a photograph of the fluorescent ceramic with a thickness of 0.15 mm in Example 1;

[0059] Figure 2 This is the XRD pattern of the fluorescent ceramic in Example 1;

[0060] Figure 3These are SEM and EDS images of the fluorescent ceramic in Example 1;

[0061] Figure 4 This is a graph showing the thermal quenching performance of the fluorescent ceramic in Example 1;

[0062] Figure 5 This is the emission spectrum of the fluorescent ceramic LED device in Example 5;

[0063] Figure 6 This is the emission spectrum of the fluorescent ceramic in Example 6;

[0064] Figure 7 The emission spectra of the fluorescent ceramic LED devices in Comparative Example 1 and Example 1 are shown. Detailed Implementation

[0065] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory 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 covered within the scope of protection intended by the present invention.

[0066] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0067] Example 1

[0068] According to the chemical formula Lu 2.99 Al5O 12 0.01Ce 3+ 18.865 g of Lu₂O₃, 8.083 g of Al₂O₃, and 0.054 g of CeO₂ were weighed sequentially and placed in a ball mill jar for 20 h using a planetary ball mill to obtain a crushed and uniformly mixed powder. The mixed powder was then placed in a tube furnace in a reducing atmosphere of N₂:H₂ = 90 vol%: 10 vol% and subjected to a high-temperature solid-state reaction at 1300 °C for 6 h to synthesize LuAG:Ce phosphor. The phosphor was then synthesized according to the chemical formula 10 wt% Al₂O₃-Lu 2.99 Al5O 12 0.01Ce 3+ 3 g of Al2O3 powder with a particle size of 1 μm was added to the synthesized LuAG:Ce phosphor, and the mixture was ball-milled twice for 24 h. The ball-milled powder was pressed into shape and then placed in a muffle furnace at 600 ℃ for 6 h to remove the binder, resulting in a ceramic green body. The green body was then placed in a vacuum tungsten filament furnace and sintered at 1750 ℃ ​​for 5 h. The fluorescent ceramic was ground to a thickness of 0.15 mm and a diameter of 25.49 mm (the actual fluorescent ceramic material obtained in this embodiment is shown in the figure). Figure 1 (As shown).

[0069] Depend on Figure 2 The XRD pattern shows that LuAG:Ce and Al2O3 phases coexist in the fluorescent ceramic, with the average grain size of the reinforcing phase Al2O3 being approximately 2 μm. Figure 3 The linear transmittance of the fluorescent ceramic is 0.9% at 850 nm, and its luminescence intensity at 200 °C is still above 95%. Figure 4 It exhibits excellent luminous stability; its thermal conductivity is 9.5 W / (m•K), and its excellent thermal conductivity effectively solves the technical problem of heat dissipation difficulties in high power density LED devices.

[0070] The fluorescent ceramic prepared in this embodiment was packaged with a 450 nm blue LED chip to form a COB light source device. At room temperature, with a driving current of 1000 mA applied, it emitted high-brightness green light. The tested performance indicators are as follows: luminous flux of 10198.0 lm, luminous efficacy of 204.7 lm / W, and peak wavelength of 525 nm. Figure 5 ).

[0071] The fluorescent ceramic prepared in this embodiment was cut to a size of 1 mm × 1 mm × 0.15 mm and packaged with a 450 nm blue LED chip to form a small-sized COB light source device. At room temperature, with a driving current of 3000 mA applied, the performance indicators obtained were as follows: luminous flux of 1062 lm, luminous efficacy of 117.8 lm / W, and peak wavelength of 530 nm (green light). Figure 6 ).

[0072] As can be seen from the above, the ultrathin fluorescent ceramic in this embodiment has excellent light and color quality and thermal conductivity, and its luminous efficacy is better than that of the previously reported LuAG:Ce fluorescent ceramic, which can meet the packaging requirements of high-brightness small-size LEDs.

[0073] Example 2

[0074] LuAG:Ce phosphor was synthesized according to the method and process parameters of Example 1. The difference from Example 1 is that the phosphor was synthesized according to the chemical formula 10 wt% MgAl2O4-Lu. 2.99 Al5O 12 0.01Ce 3+ 3 g of MgAl2O4 powder with a particle size of 200 nm was added to the synthesized LuAG:Ce phosphor and ball milled for 24 h. The powder obtained by ball milling was pressed into shape and placed in a muffle furnace at 600 °C for 6 h to remove the binder, thus obtaining a ceramic green body. The green body was placed in a vacuum tungsten filament furnace and sintered at 1750 °C for 5 h. The fluorescent ceramic was ground to a thickness of 0.15 mm.

[0075] The ultrathin fluorescent ceramic prepared in this embodiment exhibits a coexistence of LuAG:Ce and MgAl2O4 phases, with the MgAl2O4 reinforcing phase having an average grain size of 5 μm. This fluorescent ceramic demonstrates excellent luminescence stability, exhibiting a linear transmittance of 0.9% at 850 nm and a luminous intensity exceeding 94% at 200 °C. Its thermal conductivity of 8.7 W / (m•K) effectively solves the technical challenge of heat dissipation in high-power-density LED devices.

[0076] The fluorescent ceramic prepared in this embodiment was packaged with a 450 nm blue LED chip to form a COB light source device. At room temperature, a driving current of 1000 mA was applied, and it emitted high-brightness green light. The performance indicators obtained by the test are as follows: luminous flux of 10150 lm, luminous efficacy of 202.5 lm / W, and peak wavelength of 523 nm.

[0077] The fluorescent ceramic prepared in this embodiment was cut to a size of 1 mm × 1 mm × 0.15 mm and packaged with a 450 nm blue LED chip to form a small-sized COB light source device. At room temperature, a driving current of 3000 mA was applied, and the performance indicators obtained by the test are as follows: luminous flux of 1054 lm, luminous efficacy of 116.8 lm / W, and peak wavelength of 530 nm for green light.

[0078] As can be seen from the above, the ultrathin fluorescent ceramic in this embodiment has excellent light and color quality and thermal conductivity, and its luminous efficacy is better than that of the previously reported LuAG:Ce fluorescent ceramic, which can meet the packaging requirements of high-brightness small-size LEDs.

[0079] Example 3

[0080] According to the chemical formula Y 2.995 Al5O 12 0.005Ce 3+ Y₂O₃ 16.228 g, Al₂O₃ 12.232 g, CeO₂ 0.041 g, and other raw material powders were weighed sequentially and placed in a ball mill jar for 24 h using a planetary ball mill to obtain a crushed and uniformly mixed powder. The mixed powder was then placed in a tube furnace in a reducing atmosphere of N₂:CO = 95 vol%: 5 vol% and subjected to a high-temperature solid-state reaction at 1450 °C for 6 h to synthesize YAG:Ce phosphor. Following the chemical formula 5 wt% Al₂O₃-Y 2.995 Al5O 12 0.005Ce 3+1.5 g of Al2O3 powder with a particle size of 100 nm was added to the synthesized YAG:Ce phosphor and ball-milled together for 20 h. The powder obtained by ball milling was pressed into shape and placed in a muffle furnace at 700 ℃ for 6 h to remove the binder, thus obtaining a ceramic green body. The green body was then placed in a vacuum tungsten filament furnace and sintered at 1750 ℃ ​​for 5 h. The phosphor ceramic was ground to a thickness of 0.4 mm, and its linear transmittance at 850 nm was 1.5%. The luminous intensity at 200 ℃ was still higher than 90%, showing excellent luminous stability. The thermal conductivity was 12.8 W / (m•K), and the excellent thermal conductivity effectively solved the technical problem of heat dissipation difficulties in high power density LED devices.

[0081] The fluorescent ceramic prepared in this embodiment was packaged with a 450 nm blue LED chip to form a COB light source device. At room temperature, a driving current of 1000 mA was applied, and it emitted high-brightness cold white light. The performance indicators obtained by the test are as follows: luminous flux of 9203 lm, luminous efficacy of 184.1 lm / W, and peak wavelength of 536 nm for green light.

[0082] The fluorescent ceramic prepared in this embodiment was cut to a size of 1.3 mm × 1.3 mm × 0.4 mm and packaged with a 450 nm blue LED chip to form a small-sized COB light source device. At room temperature, a driving current of 5000 mA was applied, and the performance indicators obtained by the test are as follows: luminous flux of 1348 lm, luminous efficacy of 89.9 lm / W, and peak wavelength of 537 nm.

[0083] As can be seen from the above, the ultrathin fluorescent ceramic in this embodiment has excellent light and color quality and thermal conductivity, which can meet the packaging requirements of high-brightness small-size LEDs.

[0084] Example 4

[0085] According to the chemical formula Lu 1.73 Al 4.99 O 12 0.02Ce 3+ 1.25Gd 3+ 0.005Mg 2+ , 0.005Si 4+10.589 g of Lu₂O₃, 7.825 g of Al₂O₃, 0.106 g of CeO₂, 6.969 g of Gd₂O₃, 0.006 g of MgO, and 0.009 g of SiO₂ were weighed sequentially and ball-milled in a ball mill jar for 24 h using a planetary ball mill to obtain a uniformly crushed and mixed powder. The mixed powder was then placed in a tube furnace under a reducing atmosphere of N₂:CO = 90 vol%: 10 vol% and subjected to a high-temperature solid-state reaction at 1500 °C for 8 h to synthesize LuGdAG:Ce phosphor. The phosphor was then synthesized according to the chemical formula 15 wt% MgO-Lu 1.73 Al 4.99 O 12 0.02Ce 3+ 1.25Gd 3+ 0.005Mg 2 + , 0.005Si 4+ 4.5 g of MgO powder with a particle size of 40 nm was added to the synthesized LuGdAG:Ce phosphor and ball-milled together for 24 h. The powder obtained by ball milling was pressed into shape and placed in a muffle furnace at 700 ℃ for 8 h to remove the binder, thus obtaining a ceramic green body. The green body was placed in a vacuum tungsten filament furnace and sintered at 1500 ℃ for 6 h. The phosphor ceramic was ground to a thickness of 0.25 mm, and its linear transmittance at 850 nm was 1.2%. The luminous intensity at 200 ℃ was still higher than 85%, showing excellent luminous stability. The thermal conductivity was 17.6 W / (m•K), and the excellent thermal conductivity effectively solved the technical problem of heat dissipation difficulties in high power density LED devices.

[0086] The fluorescent ceramic prepared in this embodiment was packaged with a 450 nm blue LED chip to form a COB light source device. At room temperature, a driving current of 2000 mA was applied, and the performance indicators obtained by the test were as follows: luminous flux of 17809 lm, luminous efficacy of 178.5 lm / W, and peak wavelength of 565 nm for yellow light.

[0087] The fluorescent ceramic prepared in this embodiment was cut to a size of 1.25 mm × 1.25 mm × 0.25 mm and packaged with a 450 nm blue LED chip to form a small-sized COB light source device. At room temperature, a driving current of 5000 mA was applied, and the performance indicators obtained by the test are as follows: luminous flux of 1258 lm, luminous efficacy of 83.8 lm / W, and peak wavelength of 569 nm.

[0088] As can be seen from the above, the ultrathin fluorescent ceramic in this embodiment has excellent light and color quality and thermal conductivity, which can meet the packaging requirements of high-brightness small-size LEDs.

[0089] Example 5

[0090] According to the chemical formula Lu 2.97 Al 4.9 O 12 0.02Ce 3+ , 0.01Pr 3+ 0.05Mn 2+ , 0.05Si 4+ Weigh out the following components in sequence: 19.762 g of Lu₂O₃, 8.354 g of Al₂O₃, 0.291 g of Ce(NO₃)₃•6H₂O, and 6O₂. 11 Raw material powders of 0.057 g, MnO 0.119 g, and SiO2 0.101 g were placed in a ball mill jar and ball-milled for 30 h using a planetary ball mill to obtain a crushed and uniformly mixed powder. The mixed powder was then placed in a tube furnace in a reducing atmosphere of N2:H2 = 90 vol%: 10 vol% and subjected to a high-temperature solid-state reaction at 1350 ℃ for 10 h to synthesize LuAG:Ce, Pr, Mn phosphor. Following the chemical formula 5 wt% BaAl2O4-Lu 2.97 Al 4.9 O 12 0.02Ce 3+ , 0.01Pr 3+ 0.05Mn 2+ , 0.05Si 4+ 1.5 g of BaAl2O4 powder with a particle size of 60 nm was added to the synthesized LuAG:Ce, Pr, Mn phosphor and ball-milled together for 30 h. The powder obtained by ball milling was pressed into shape and placed in a muffle furnace for debinding at 800 ℃ for 4 h to obtain a ceramic green body. The green body was placed in a vacuum tungsten filament furnace for high-temperature sintering at 1750 ℃ ​​for 8 h. The phosphor ceramic was ground to a thickness of 0.1 mm, and its linear transmittance at 850 nm was 1.7%. The luminous intensity at 200 ℃ was still higher than 89%, showing excellent luminous stability. The thermal conductivity was 10.5 W / (m•K), and the excellent thermal conductivity effectively solved the technical problem of heat dissipation difficulties in high power density LED devices.

[0091] The fluorescent ceramic prepared in this embodiment was packaged with a 450 nm blue LED chip to form a COB light source device. At room temperature, a driving current of 1000 mA was applied. Because Ce... 3+ Pr 3+ and Mn 2+ The co-emitting LED emits high-brightness white light. The tested performance indicators are as follows: luminous flux of 6509 lm, luminous efficacy of 130.3 lm / W, and color rendering index of 86.

[0092] The fluorescent ceramic prepared in this embodiment was cut to a size of 1 mm × 1 mm × 0.1 mm and packaged with a 450 nm blue LED chip to form a small-sized COB light source device. At room temperature, a driving current of 2500 mA was applied, and the performance indicators obtained by the test are as follows: luminous flux of 854 lm and luminous efficacy of 113.5 lm / W.

[0093] As can be seen from the above, the ultrathin fluorescent ceramic in this embodiment has excellent light and color quality and thermal conductivity, which can meet the packaging requirements of high-brightness small-size LEDs.

[0094] Example 6

[0095] According to the chemical formula Y 2.47 AlO 12 0.03Ce 3+ 0.5Gd 3+ , 2Mg 2+ , 2Si 4+ Y₂O₃ 12.559 g, Al₂O₃ 2.296 g, CeO₂ 0.232 g, Gd₂O₃ 4.081 g, MgO 3.630 g, SiO₂ 5.411 g were weighed sequentially and ball-milled in a ball mill jar using a planetary ball mill for 24 h to obtain a crushed and uniformly mixed powder. The mixed powder was then placed in a tube furnace in a reducing atmosphere of N₂:H₂ = 90 vol%: 10 vol% and subjected to a high-temperature solid-state reaction at 1350 ℃ for 10 h to synthesize YGdMASG:Ce phosphor. Following the chemical formula 6 wt% BaAl₂O₄-Y 2.47 AlO 12 0.03Ce 3+ 0.5Gd 3+ , 2Mg 2+ , 2Si 4+ 1.8 g of BaAl2O4 powder with a particle size of 100 nm was added to the synthesized YGdMASG:Ce phosphor and ball-milled together for 25 h. The powder obtained by ball milling was pressed into shape and placed in a muffle furnace for debinding at 600 ℃ for 5 h to obtain a ceramic green body. The green body was placed in a vacuum tungsten filament furnace for high-temperature sintering at 1500 ℃ for 4 h. The phosphor ceramic was ground to a thickness of 0.15 mm, and its linear transmittance at 850 nm was 1.1%. The luminous intensity at 200 ℃ was still higher than 80%, showing excellent luminous stability. The thermal conductivity was 6.3 W / (m•K), and the excellent thermal conductivity effectively solved the technical problem of heat dissipation difficulties in high power density LED devices.

[0096] The fluorescent ceramic prepared in this embodiment was packaged with a 450 nm blue LED chip to form a COB light source device. At room temperature, with a driving current of 1000 mA, high-brightness red light was produced. The tested performance indicators are as follows: luminous flux of 2750 lm, luminous efficacy of 56 lm / W, and peak wavelength of 602 nm. Figure 6 )

[0097] The fluorescent ceramic prepared in this embodiment was cut to a size of 0.8 mm × 0.8 mm × 0.15 mm and packaged with a 450 nm blue LED chip to form a small-sized COB light source device. At room temperature, a driving current of 1500 mA was applied, and the performance indicators obtained by the test are as follows: luminous flux of 280 lm, luminous efficacy of 62.9 lm / W, and peak wavelength of 603 nm.

[0098] As can be seen from the above, the ultrathin fluorescent ceramic in this embodiment has excellent light and color quality and thermal conductivity, which can meet the packaging requirements of high-brightness small-size LEDs.

[0099] Comparative Example 1

[0100] Ultrathin fluorescent ceramics were prepared according to the formulation design, process parameters, and procedures of Example 1. Unlike Example 1, Comparative Example 1 did not include the reinforcing phase Al₂O₃: according to the chemical formula Lu… 2.99 Al5O 12 0.01Ce 3+ 18.865 g of Lu2O3, 8.083 g of Al2O3, and 0.054 g of CeO2 were weighed sequentially and placed in a ball mill jar for 20 h of planetary ball milling to obtain a crushed and uniformly mixed powder. The mixed powder was then placed in a tube furnace in a reducing atmosphere of N2:H2 = 90 vol%: 10 vol% and subjected to a high-temperature solid-state reaction at 1300℃ for 6 h to synthesize LuAG:Ce phosphor. The phosphor ceramic was then ground to a thickness of 0.15 mm.

[0101] The prepared fluorescent ceramic was packaged with a 450 nm blue LED chip to form a COB light source device. At room temperature, a driving current of 1000 mA was applied, and the following performance indicators were obtained: luminous flux of 9297.1 lm, luminous efficacy of 187.1 lm / W, and peak wavelength of 526 nm.

[0102] The prepared fluorescent ceramic was cut to a size of 1 mm × 1 mm × 0.15 mm and packaged with a 450 nm blue LED chip to form a small-sized COB light source device. At room temperature, a driving current of 3000 mA was applied, and the performance indicators obtained by the test are as follows: luminous flux of 1012 lm, luminous efficacy of 112.4 lm / W, and peak wavelength of 527 nm.

[0103] As can be seen from the above, the ultrathin fluorescent ceramic in this comparative example has a single-phase structure without a reinforcing phase, resulting in a reduced number of grain boundaries, a weakened grain boundary light scattering enhancement effect, and a lower luminous efficiency than in Example 1. Figure 7 This demonstrates the superiority of the light scattering enhancement concept proposed in this invention for preparing high-efficiency ultrathin fluorescent ceramics.

[0104] Comparative Example 2

[0105] Ultrathin fluorescent ceramics were prepared according to the formulation design and process parameters of Example 2. The difference from Example 2 is that 10 wt% MgAl₂O₄-Lu was used. 2.99 Al5O 12 0.01Ce 3+ After weighing 18.865 g of Lu2O3, 8.083 g of Al2O3, and 0.054 g of CeO2 in sequence, 3 g of MgAl2O4 reinforcing phase with a particle size of 200 nm was added. The above powders were ball-milled together for 24 h, then pressed into shape and placed in a muffle furnace for debinding at 600 ℃ for 6 h to obtain a ceramic green body. The green body was then placed in a vacuum tungsten filament furnace for high-temperature sintering at 1750 ℃ ​​for 5 h. The fluorescent ceramic was ground to a thickness of 0.15 mm and a diameter of 25.49 mm, without the step of synthesizing fluorescent powder.

[0106] The prepared fluorescent ceramic was packaged with a 450 nm blue LED chip to form a COB light source device. The performance indicators obtained at room temperature are as follows: luminous flux of 8526.5 lm, luminous efficacy of 171.3 lm / W, and peak wavelength of 528 nm.

[0107] The prepared fluorescent ceramic was cut to a size of 1 mm × 1 mm × 0.15 mm and packaged with a blue LED chip to form a small-sized COB light source device. At room temperature, a driving current of 3000 mA was applied, and the performance indicators obtained by the test were as follows: luminous flux of 980.5 lm, luminous efficacy of 108.9 lm / W, and peak wavelength of 527 nm.

[0108] It can be seen that, compared with the traditional solid-state reaction sintering method, the light scattering enhancement proposed in this invention is beneficial to improving the light efficiency and luminous intensity of the prepared high-efficiency ultrathin fluorescent ceramics.

[0109] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a fluorescent ceramic material, characterized in that, The preparation method includes the following steps: after subjecting raw materials including Y source, Al source, E source, M source, X source and Ce source to a high-temperature solid-state reaction, light scattering enhancement phase A is added, and after pressing and molding, the raw materials are then debinded and sintered at high temperature to obtain the final product. The high-temperature solid-phase reaction is carried out at a temperature of 1300~1500 ℃ for 6~8 h. The temperature for degreasing is 600~800 ℃, and the reaction time for degreasing is 6~8 h; The high-temperature sintering temperature is 1500~1800 ℃; the high-temperature sintering time is 5~10 h; The chemical composition of the fluorescent ceramic material is AY. 3-x-y Al 5-2z O 12 : x Ce 3+ , y E 3+ , z M 2+ , z X 4+ ,in: x For Ce 3+ Doping level of luminescent centers y For E 3+ Occupy Y 3+ The doping amount of the bit, z For M 2+ X 4+ Occupy Al 3+ Doping level of the bit; 0.0≤ x ≤0.3; 0.0≤ y ≤3.0; 0.0≤ z ≤0.5, and x + y ≤3.0, and x, y, z are not all 0 at the same time; Phase A is the light scattering enhancement phase, and its mass percentage (5-20 wt%) is based on the total weight of the fluorescent ceramic. The light scattering enhancement phase A is selected from at least one of Al2O3, Y2O3, Lu2O3, MgAl2O4, BaAl2O4, and MgO; E, M, and X are doping elements that play a role in spectral modulation; X and M are introduced simultaneously as ion pairs to balance the charge. E is selected from at least one of Lu, Ga, Sc, Pr, Tb, Gd, Eu, and Sm; M is selected from at least one of Mg, Ca, Sr, Ba and Mn; X is selected from at least one of Si, Zr, Ti, and Ge.

2. The method for preparing fluorescent ceramic materials according to claim 1, characterized in that, The fluorescent ceramic material consists of a light scattering enhancement phase A and a main phase Y. 3-x-y Al 5-2z O 12 : x Ce 3+ , y E 3+ , z M 2+ , z X 4+ composition.

3. The method for preparing fluorescent ceramic materials according to claim 2, characterized in that, The average grain size of the reinforcing phase A is 10 nm to 1 μm.

4. The preparation method according to any one of claims 1-3, characterized in that, The thickness of the fluorescent ceramic material is 0.10-0.40 mm; And / or, the peak wavelength of the emission spectrum of the fluorescent ceramic material is 500~700 nm; And / or, the fluorescent ceramic material has a luminous efficacy of 113.2 ~ 211.0 lm / W when excited by a blue LED chip; And / or, the luminous flux of the fluorescent ceramic material is 5000~11100 lm.

5. The preparation method according to any one of claims 1-3, characterized in that, The Y source is provided by at least one of oxides, hydroxides, carbonates, chlorides and nitrates containing the element Y; And / or, the Al source is provided by at least one of Al-containing oxides, hydroxides, carbonates, chlorides and nitrates; And / or, the E source is provided by at least one of oxides, hydroxides, carbonates, chlorides and nitrates containing E; And / or, the M source is provided by at least one of oxides, hydroxides, carbonates, chlorides and nitrates containing the element M; And / or, the X source is provided by at least one of oxides, hydroxides, carbonates, chlorides and nitrates containing the element X; And / or, the Ce source is provided by a Ce-containing compound selected from at least one of CeO2, CeCl3, Ce(SO4)2•4H2O, and Ce(NO3)3•6H2O.

6. The preparation method according to any one of claims 1-3, characterized in that, The high-temperature solid-phase reaction is carried out under a reducing atmosphere, which is either a N2-H2 mixture or a N2-CO mixture.

7. The preparation method according to any one of claims 1-3, characterized in that, The preparation method of the fluorescent ceramic material includes the following steps: (1) Ball milling and mixing: with the main phase chemical formula Y 3-x-y Al 5-2z O 12 : x Ce 3+ , y E 3+ , z M 2+ , z X 4+ Weigh out the Y source, Al source, E source, M source, X source and Ce source, and perform ball milling; (2) Synthesis of phosphor: The ball-milled powder from step (1) is subjected to a high-temperature solid-phase reaction in a reducing atmosphere; (3) Introducing light scattering enhancement phase A: Add light scattering enhancement phase A to the phosphor in step (2) and perform secondary ball milling; (4) Green body forming: After pressing the mixed powder from step (3) into shape, the binder is removed to obtain a ceramic green body; (5) Ceramic sintering: The green body from step (4) is sintered at high temperature to obtain fluorescent ceramic material; (6) Grinding: The fluorescent ceramic material is machined to a thickness of 0.10-0.40 mm to obtain ceramic products.

8. The application of the fluorescent ceramic material prepared by the preparation method according to any one of claims 1-7 in LEDs.

9. The application as described in claim 8, wherein the fluorescent ceramic material is used in high-power miniLEDs and chip-level LED small-size LED light source devices.

10. A fluorescent ceramic LED device, characterized in that, It contains fluorescent ceramic materials prepared by the preparation method according to any one of claims 1-7.

11. The fluorescent ceramic LED device as described in claim 10, characterized in that, The LED device is an LED lighting or display device.

12. The fluorescent ceramic LED device as described in claim 11, characterized in that, The LED device is a high-power miniLED or a chip-level LED small-size LED light source device.

13. The fluorescent ceramic LED device according to any one of claims 10-12, characterized in that, The LED device also includes a blue LED chip excitation light source.

14. The fluorescent ceramic LED device as described in claim 13, characterized in that, The fluorescent ceramic LED device has a peak emission wavelength of 500~530 nm and a luminous efficacy of not less than 190 lm / W.

15. The fluorescent ceramic LED device as described in claim 13, characterized in that, The fluorescent ceramic LED device has a peak emission wavelength of 530~560 nm and a luminous efficacy of not less than 150 lm / W.

16. The fluorescent ceramic LED device as described in claim 13, characterized in that, The fluorescent ceramic LED device has a peak emission wavelength of 560~590 nm and a luminous efficacy of not less than 100 lm / W.

17. The fluorescent ceramic LED device as described in claim 11, characterized in that, The LED lighting or display device is an automotive headlight or an AR-HUD light source.

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