A striped composite structure fluorescent material and a preparation method and application thereof

Abstract

The application discloses a striped composite structure fluorescent material and a preparation method and application thereof. The application solves the problems of narrow emission spectrum, poor light color quality and reabsorption of existing single crystal structure fluorescent ceramic applied to solid state lighting and display by coating red and green fluorescent films with equal width and height alternately on the surface of a YAG:Ce fluorescent ceramic main structure. The gel-state red and green fluorescent materials are coated on the surface of the YAG:Ce fluorescent ceramic with equal width and height by a strip-shaped mold, and the striped composite structure fluorescent material is prepared by using argon atmosphere and low-temperature sintering technology. The YAG:Ce fluorescent ceramic can effectively conduct heat and emit yellow light, the red and green striped fluorescent materials are alternately arranged and do not reabsorb each other, the proposed composite structure fluorescent material obtains high-quality white light under the excitation of a blue light LED / LD, high heat conduction, high color rendering index and high light efficiency lighting can be realized, and the fluorescent material can be widely applied to the fields of white light LED / laser lighting and display after being packaged with a blue light LED excitation source.

Description

Technical Field

[0001] This invention relates to the field of inorganic light-emitting materials, specifically to a high color rendering index, high luminous efficiency, and high thermal conductivity composite fluorescent material for white LEDs / LDs and its preparation method. Background Technology

[0002] Against the backdrop of increasingly severe global problems such as energy crisis, climate change, and environmental pollution, solid-state lighting technology based on semiconductor chips is considered the next generation of green solid-state lighting sources for the 21st century due to its significant advantages such as energy saving, high reliability, long lifespan, high luminous efficiency, and environmental friendliness. With the rapid development of the solid-state lighting industry, a new lighting method, "full-spectrum lighting," is emerging rapidly. The emission spectrum of "full-spectrum lighting" is similar to that of sunlight, possessing light across all wavelengths in the visible light region and effectively reproducing the true colors of illuminated objects. However, the mainstream implementation scheme for white LED / LD light sources currently still uses blue LED / LDs to excite garnet-type YAG:Ce yellow phosphors. The emission spectrum of YAG:Ce yellow phosphors lacks green and red components, therefore white LED / LD light sources face challenges such as low color rendering index, high color temperature, and poor light quality, making it difficult to achieve full-spectrum lighting.

[0003] Currently, researchers mainly use the following methods to modulate the fluorescent spectrum of YAG:Ce ceramics: ① co-doping with luminescent ions (Journal of Materials Chemistry C, 2020, 8(13):4329-4337.), such as Cr 3+ Pr 3+ Mn 2+ 、Sm 3+ However, this scheme provides limited red light, and there is energy transfer between the co-doped luminescent ions, thus reducing the luminescence efficiency; ② By stacking YAG:Ce fluorescent ceramics with fluorescent ceramics that emit red light (Optics Express, 2023, 31(15):24914-24925.), however, this scheme severely limits the luminescence efficiency of each emitting layer, lacks the cyan light component, and has a high cost; ③ Adjusting the chemical composition of the matrix (CN111393166A), by replacing the octahedral Al sites with rare earth element Sc, and Gd 3+ Ion-substituted dodecahedral Y 3+ While ions effectively solve the problem of insufficient blue-green light in fluorescent ceramics, they are insufficient in red light and cannot achieve full-spectrum illumination.

[0004] Chinese invention patent CN113979739A describes a composite fluorescent ceramic composed of multiple fluorescent ceramics arranged alternately on a plane. This composite is then placed vertically on the excitation surface of a light-emitting chip to create a light-emitting device. Different colors of light can be emitted from the composite fluorescent ceramic when excited by the same light-emitting chip, and these different colors combine to form uniform white light. However, due to the small spot size of laser illumination, this composite fluorescent ceramic structure is only suitable for white LED lighting. Furthermore, it lacks a green light layer, preventing full-spectrum illumination, and its manufacturing cost is high.

[0005] In summary, fluorescent ceramics used in white LEDs / LDs suffer from problems such as low color rendering index, low luminous efficiency, and re-collection due to their inability to achieve full-spectrum emission. Therefore, developing composite fluorescent materials that can solve these problems is urgently needed. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a striped composite fluorescent material, its preparation method, and its application. This striped composite fluorescent material serves as a high-quality luminescent fluorescent material for white LED / LD lighting. This composite fluorescent material effectively solves problems such as low color quality and low luminous efficiency in ceramic materials. Furthermore, the entire preparation process is simple, stable, controllable, and low-cost.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A striped composite fluorescent material is provided, comprising a yellow fluorescent ceramic main structure and alternating red and green fluorescent films of equal width and thickness coated on the upper surface of the yellow fluorescent ceramic main structure. The thickness of the yellow fluorescent ceramic is 1-1.8 mm, the thickness of the red and green fluorescent films is 50-60 μm, and the width of the red and green fluorescent glass films is 1-1.5 mm.

[0009] The chemical composition of the yellow fluorescent ceramic main structure is (Y). 1-x Ce x )3Al5O 12 0.001≤x≤0.01; the chemical composition of the red fluorescent film is (Sr,Ca)AlSiN3:Eu 2+ The chemical composition of the green fluorescent film is β-SiAlON:Eu. 2+ .

[0010] The yellow fluorescent ceramic is garnet ceramic (Y). 1-x Ce x )3Al5O 12 Ce 3+The ion concentration is 0.2 at%-1.0 at%, and the weight ratio of green phosphor in the green fluorescent film to red phosphor in the red fluorescent film is (1-5):1, preferably (1-2):1.

[0011] The phosphor used in the red fluorescent film is (Sr,Ca)AlSiN3:Eu. 2+ The particle size is 200nm-250nm; the phosphor used in the green fluorescent film is β-SiAlON:Eu. 2+ The particle size is 200nm-250nm.

[0012] This invention also provides a method for preparing the striped composite fluorescent material, which utilizes a solid-state reaction method combined with vacuum sintering technology to prepare yellow fluorescent ceramics (Y). 1-x Ce x )3Al5O 12 The fluorescent ceramic sheet is YAG:Ce fluorescent ceramic. Then, red and green fluorescent film pastes are coated onto the surface of the yellow fluorescent ceramic using a doctor blade. The striped composite structure fluorescent material is then prepared using low-temperature sintering technology, specifically including the following steps:

[0013] (1) YAG:Ce fluorescent ceramics were prepared using solid-state reaction technology;

[0014] (2) After coating the gel-state red and green fluorescent glass films onto YAG:Ce fluorescent ceramics using a mold, striped composite fluorescent materials are obtained by low-temperature sintering technology.

[0015] Furthermore, the preparation method of YAG:Ce fluorescent ceramic in step (1) is as follows:

[0016] ①According to the stoichiometric formula (Y 1-x Ce x )3Al5O 12 The required powder raw materials, namely Al2O3, Y2O3 and CeO2, were accurately weighed with a ratio of 0.001≤x≤0.01. They were then placed in a nylon ball mill jar for planetary ball milling for 15-25 hours. The ball milling speed was set to 200 r / min, the ball milling beads were Al2O3 balls, and the ball milling medium was anhydrous ethanol. The slurry after ball milling was poured into an evaporating dish and placed in an 80℃ electric heating drying oven for 24 hours. After that, it was passed through a 200-mesh sieve 5 times to obtain a mixed powder.

[0017] ② The mixed powder is placed in a stainless steel mold with a diameter of 22mm, and unidirectional pressure is applied to it by a press to make it into a green blank with a certain strength. The applied pressure is 20Mpa and the holding time is 5min. After the dry-pressed green blank is packaged, it is placed in a cold isostatic press for cold isostatic pressing treatment. The holding pressure is 300Mpa and the holding time is 300s. The obtained green blank is calcined in an air atmosphere in a muffle furnace at 800-900℃ for 10h to remove impurities.

[0018] ③ The cleaned green billet is placed in a vacuum tungsten filament furnace at 1765℃ and 5×10 -4 After sintering under a vacuum of Pa for 10 hours, the ceramic was annealed in air at 1450℃ for 10 hours. The annealed ceramic was then polished on both sides to 1 mm to obtain YAG:Ce fluorescent ceramic.

[0019] Furthermore, the preparation method of the striped composite fluorescent material in step (2) is as follows:

[0020] ① The required powder raw materials were accurately weighed using an analytical balance according to the stoichiometric formula 38SiO2-40B2O3-4ZnO-4Na2O-3Al2O3-1Li2O (mol%). The powder raw materials were SiO2, B2O3, ZnO, Na2O, Al2O3 and Li2O. The powder was then placed in an agate mortar and ground thoroughly. The ground powder was poured into an alumina crucible and sintered in a high-temperature furnace at 1300℃ for 2 hours to obtain a molten liquid. The molten liquid was then poured into a copper mold and cooled to obtain a precursor glass block. Finally, the precursor glass block was ground into powder and passed through a 100-mesh sieve to obtain precursor glass powder.

[0021] ② The precursor glass powder is mixed with commercial (Sr,Ca)AlSiN3:Eu 2+ A red fluorescent glass film slurry was prepared by mixing red phosphor and organic binder. The precursor glass powder was then mixed with commercially available (Sr,Ca)AlSiN3:Eu... 2+ Based on a total mass of 0.5g of red phosphor, the organic binder consists of: 0.15g ethyl cellulose, 150μL terpineol, and 300μL ethyl acetate; the precursor glass powder is then mixed with commercial β-SiAlON:Eu 2+ Green phosphor is mixed with organic binder to obtain green fluorescent glass film slurry, and precursor glass powder is mixed with commercial β-SiAlON:Eu 2+ Based on a total mass of 0.5g of green phosphor, the composition of the organic binder is: 0.15g ethyl cellulose, 150μL terpineol, and 300μL ethyl acetate; wherein the weight ratio of green phosphor to precursor glass powder is 3:1, and the weight ratio of green phosphor to red phosphor is (1-5):1.

[0022] Furthermore, β-SiAlON:Eu2+ Green phosphor and (Sr,Ca)AlSiN3:Eu 2+ The weight ratio of red phosphor is 1:1, 2:1, 3:1, 4:1, or 5:1. Preferably, the green fluorescent glass film contains 0.125g of glass powder and 0.375g of green phosphor, while the red fluorescent glass film contains 0.125-0.425g of glass powder and 0.075-0.375g of red phosphor.

[0023] ③ Place the 3D printing mold on the YAG:Ce fluorescent ceramic sheet and fix it to the glass substrate with tape. Apply red fluorescent glass film slurry to the YAG:Ce ceramic sheet using a scraper through the 3D printing mold. Dry in a 150℃ electric heating drying oven for 3 hours. Then, move the 3D printing mold on the YAG:Ce fluorescent ceramic sheet by the width of the red fluorescent film and fix it to the glass substrate again. Apply green fluorescent glass film slurry to the YAG:Ce ceramic sheet using a scraper through the 3D printing mold. Dry in a 150℃ electric heating drying oven for 3 hours. The resulting composite fluorescent material is sintered to obtain a striped composite fluorescent material.

[0024] Furthermore, the sintering process is as follows: holding at 120℃-130℃ for 0.5h-1h, holding at 400℃-450℃ for 0.5h-1h, and after the holding is completed, the sample is cooled to room temperature in an argon atmosphere with the furnace.

[0025] The present invention also provides the application of the striped composite structure fluorescent material in the field of fluorescence conversion white LED / LD lighting, characterized in that: when it is applied to white LED lighting devices, the excitation source is a blue LED chip; when it is applied to white LD lighting devices, the excitation source is a blue LD chip.

[0026] Furthermore, under the excitation of a 450-460nm blue LED / LD chip, the first layer of YAG:Ce fluorescent ceramic matrix emits yellow light, while the second layer of red and green fluorescent glass films emits red and green light, respectively. These light rays mix with the unabsorbed blue light to form white light, effectively preventing the reabsorption of red and green light by the materials. The resulting white LED / LD has a color temperature of 3000-6000K, a color rendering index of 86-94, and a luminous efficacy of 140-180 lm / W.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) This invention effectively avoids the photon reabsorption effect caused by the alternating and cyclic arrangement of red and green light stripe films on a YAG:Ce ceramic sheet, thereby mitigating the "photometric-chromaticity contradiction" to a certain extent. Simultaneously, the composite fluorescent material prepared by this structure can improve the heat transfer process, thus effectively avoiding heat accumulation under high-power LDs. The β-SiAlON:Eu coating in this structure... 2+ The fluorescent glass film, when excited by a 450-460nm blue LED / LD, can emit green fluorescence with a center wavelength of 520-530nm, effectively improving the green valley effect in white LED / laser illumination; Furthermore, (Sr,Ca)AlSiN3:Eu 2+ When excited by a 450-460nm blue LED / LD, the fluorescent glass film can emit red fluorescence with a center wavelength of 625-635nm, which makes up for the problem of insufficient red light in YAG:Ce fluorescent materials.

[0029] (2) When the striped composite fluorescent material of the present invention is excited by a 450-460nm blue LED / LD chip, the YAG:Ce ceramic, red light and green light striped film emit yellow light, red light and green light respectively, which are mixed with the unabsorbed blue light to obtain high-quality white light, realizing full-spectrum white LED / LD lighting with a color rendering index of 86-96 and a color temperature of 3000-6000K.

[0030] (3) This invention employs low-temperature sintering technology to achieve integrated molding of three fluorescent materials. Furthermore, due to the excellent thermal conductivity of YAG:Ce fluorescent ceramic, using YAG:Ce fluorescent ceramic as the main structure minimizes the impact of coating with striped fluorescent glass film. Therefore, the composite fluorescent material exhibits excellent thermal conductivity, with a thermal conductivity of 7-9 W / m². -1 K -1 .

[0031] (4) This invention provides a method for preparing a composite fluorescent material containing stripes. The fluorescent glass film prepared by this method has controllable thickness, is simple in process, and is suitable for large-scale production. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a physical image of the striped composite fluorescent material of the present invention.

[0034] Figure 2 This is a schematic diagram of the striped composite fluorescent material of the present invention.

[0035] Figure 3 This is a schematic diagram of the structure of the red and green fluorescent films of the striped composite fluorescent material of the present invention.

[0036] Figure 4 3D printing molds for preparing striped red and green fluorescent films for this invention (left - model image, right - actual object image).

[0037] Figure 5 The XRD patterns are of the green fluorescent film and the red fluorescent film in the striped composite fluorescent material prepared in Example 2 of this invention.

[0038] Figure 6 This is a cross-sectional microstructure SEM image of the striped composite fluorescent material in Example 2 of the present invention (Region 1: green fluorescent film, Region 2: YAG:Ce fluorescent ceramic).

[0039] Figure 7 This is the temperature-dependent emission spectrum of the striped composite fluorescent material in Example 2 of the present invention.

[0040] Figure 8 This is a comparison diagram of the thermal conductivity of the YAG:Ce fluorescent ceramic and the striped composite fluorescent material prepared in Example 2 of the present invention.

[0041] Figure 9 The image shows the electroluminescence spectrum of the striped composite fluorescent material prepared in Example 2 of this invention under blue LED excitation.

[0042] Figure 10 The image shows the electroluminescence spectrum of the striped composite fluorescent material prepared in Example 2 of this invention under blue light LD excitation.

[0043] In the figure, 1 is the yellow fluorescent ceramic main structure, 2 is the red fluorescent film, and 3 is the green fluorescent film; Detailed Implementation

[0044] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. The raw materials used in the following examples are all commercially available products with a purity greater than 99.9%. (Sr,Ca)AlSiN3:Eu 2+ and β-SiAlON:Eu 2+ The particle size is between 200nm and 250nm. The glass matrix particle size is between 50nm and 150nm.

[0045] Example 1

[0046] In this embodiment, the striped composite fluorescent material is as follows: Figures 1-2As shown, the striped composite fluorescent material consists of a yellow fluorescent ceramic main structure 1 and alternating layers of red fluorescent film 3 and green fluorescent film 2 with equal width and height coated on the surface of the yellow fluorescent ceramic main structure. The yellow fluorescent ceramic main structure is YAG:Ce fluorescent ceramic with a chemical composition of (YAG:Ce). 0.998 Ce 0.002 )3Al5O 12 The chemical composition of the red fluorescent film is (Sr,Ca)AlSiN3:Eu. 2+ The chemical composition of the green fluorescent film is β-SiAlON:Eu. 2+ .

[0047] In this embodiment, the thickness of the yellow fluorescent ceramic main structure is 1 mm, the thickness of the red and green fluorescent films is 50 μm, and the width of the red and green fluorescent glass films is 1 mm.

[0048] The preparation method of the striped composite structure fluorescent material in this embodiment is as follows:

[0049] (1) According to the stoichiometric formula (Y 0.998 Ce 0.002 )3Al5O 12 The required powder raw materials, namely Al2O3, Y2O3, and CeO2, were accurately weighed and then placed in a nylon ball mill jar for planetary ball milling for 16 hours. The ball milling speed was set to 200 r / min, the grinding beads were Al2O3 balls, and the grinding media was anhydrous ethanol. The ball-milled slurry was poured into an evaporating dish and dried in an 80℃ electric hot air drying oven for 24 hours, and then passed through a 200-mesh sieve 5 times. The mixed powder was placed in a 22mm diameter stainless steel mold and subjected to unidirectional pressure of 20 MPa for 5 minutes to form a green blank with a certain strength. After dry pressing, the green blank was packaged and placed in a cold isostatic press for cold isostatic pressing (holding pressure of 300 MPa for 300 seconds). The obtained green blank was then calcined in a muffle furnace at 800℃ in air atmosphere for 10 hours to remove impurities. The blank was placed in a vacuum tungsten filament furnace at 5×10 -4 After sintering at 1765℃ for 10 hours under a vacuum of Pa, the ceramic was annealed in air at 1450℃ for 10 hours. The annealed ceramic was then polished on both sides to 1 mm to obtain YAG:Ce fluorescent ceramic.

[0050] (2) The required powder raw materials were accurately weighed according to the stoichiometric formula 38SiO2-40B2O3-4ZnO-4Na2O-3Al2O3-1Li2O (mol%), wherein the powder raw materials were SiO2, B2O3, ZnO, Na2O, Al2O3 and Li2O, and then placed in an agate mortar and ground thoroughly. The ground mixed powder was poured into an alumina crucible and sintered in a high-temperature furnace at 1300℃ for 2 hours. Then the molten liquid was poured into a copper mold to cool. Finally, the precursor glass block was ground into powder and passed through a 100-mesh sieve to obtain precursor glass powder. 0.125g of precursor glass powder was mixed with 0.375g of commercial red phosphor (Sr,Ca)AlSiN3:Eu 2+ A red fluorescent glass film slurry was prepared by mixing an organic binder phase consisting of 0.15 g ethyl cellulose, 150 μL terpineol, and 300 μL ethyl acetate; 0.125 g of precursor glass powder was mixed with 0.375 g of commercially available green phosphor β-SiAlON:Eu 2+ A green fluorescent glass film slurry was obtained by mixing an organic binder consisting of 1 mL terpineol, 3 mL ethyl acetate, and 1 g ethyl cellulose.

[0051] (3) Place the 3D printed mold on the YAG:Ce fluorescent ceramic sheet and fix it to the glass substrate with tape. The structure of the 3D printed mold is as follows: Figure 4 As shown, the 3D printing mold uses a plastic plate with rectangular holes spaced at equal intervals of 1 mm, and the width of each rectangular hole is 1 mm. A red fluorescent glass film slurry, 50-60 μm thick, is scraped onto a YAG:Ce ceramic sheet using the 3D printing mold. The sheet is then dried in a 150℃ electric heating oven for 3 hours. Next, the 3D printing mold is moved across the YAG:Ce fluorescent ceramic sheet by the width of the red fluorescent film and fixed back onto the glass substrate. A green fluorescent glass film slurry, 50-60 μm thick, is then scraped onto the YAG:Ce ceramic sheet using the 3D printing mold and dried in a 150℃ electric heating oven for 3 hours. The resulting composite fluorescent material is sintered to obtain a striped composite fluorescent material. The sintering process is as follows: holding at 120℃ for 40 min, holding at 400℃ for 1 h, and then cooling the sample to room temperature in an argon atmosphere. The resulting striped composite fluorescent material has a thermal conductivity of 7 W / m². -1 K -1 .

[0052] The obtained striped composite fluorescent material was encapsulated with a 460nm blue LED chip to obtain a white light source with a correlated color temperature of 3184K, a color rendering index of 93.1, color coordinates (0.3345, 0.3326), and a luminous efficacy of 142.1 lm / W; when encapsulated with a 460nm blue LD chip, a white light source with a correlated color temperature of 4569K, a color rendering index of 90, color coordinates (0.3376, 0.3311), and a luminous efficacy of 172.4 lm / W was obtained.

[0053] Example 2

[0054] In this embodiment, the chemical composition of the yellow fluorescent ceramic main structure YAG:Ce fluorescent ceramic is (Y 0.996 Ce 0.004 )3Al5O 12 The weight ratio of green phosphor in the green fluorescent film to red phosphor in the red fluorescent film is 2:1. In this embodiment, the thickness of the yellow fluorescent ceramic main structure is 1 mm, the thickness of both the red and green fluorescent films is 50 μm, and the width of both the red and green fluorescent glass films is 1 mm.

[0055] The preparation method of red and green fluorescent glass film paste is as follows: 0.3125g of precursor glass powder and 0.1875g of commercial red phosphor (Sr,Ca)AlSiN3:Eu 2+ A red fluorescent glass film slurry was prepared by mixing an organic binder consisting of 1 mL terpineol, 3 mL ethyl acetate, and 1 g ethyl cellulose; 0.125 g of precursor glass powder was mixed with 0.375 g of commercially available green phosphor β-SiAlON:Eu 2+ A green fluorescent glass film slurry was obtained by mixing an organic binder consisting of 1 mL terpineol, 3 mL ethyl acetate, and 1 g ethyl cellulose.

[0056] The other implementation steps are the same as in Example 1.

[0057] The striped composite fluorescent material prepared in this embodiment has a thermal conductivity of 8 W / m². -1 K -1 .

[0058] The obtained composite fluorescent material was encapsulated with a 460nm blue LED chip to obtain a white light source with a correlated color temperature of 3911K, a color rendering index of 94, color coordinates (0.3336, 0.3312), and a luminous efficacy of 145.8 lm / W; and encapsulated with a 460nm blue LD chip to obtain a white light source with a correlated color temperature of 4861K, a color rendering index of 91.4, color coordinates (0.3354, 0.3309), and a luminous efficacy of 171.8 lm / W.

[0059] Figure 6This is a SEM image of the microstructure at the interface between the red and green fluorescent glass films in the striped composite fluorescent material of Example 2. The SEM cross-sectional image shows that the fluorescent glass film is tightly bonded to the YAG:Ce fluorescent ceramic, exhibiting excellent film-forming properties. Figure 7 The image shows the temperature-dependent emission spectrum of the striped composite fluorescent material in Example 2. From... Figure 7 As can be seen, the luminescence intensity of the composite fluorescent material decreases slightly with increasing temperature, but it still maintains 66% at 473K, demonstrating good thermal stability.

[0060] Example 3

[0061] In this embodiment, the chemical composition of the yellow fluorescent ceramic main structure YAG:Ce fluorescent ceramic is (Y 0.994 Ce 0.006 )3Al5O 12 The weight ratio of green phosphor in the green fluorescent film to red phosphor in the red fluorescent film is 3:1.

[0062] The preparation method of red and green fluorescent glass film paste is as follows: 0.375g of precursor glass powder and 0.125g of commercial red phosphor (Sr,Ca)AlSiN3:Eu 2+ A red fluorescent glass film slurry was prepared by mixing an organic binder phase consisting of 0.15 g ethyl cellulose, 150 μL terpineol, and 300 μL ethyl acetate; 0.125 g of precursor glass powder was mixed with 0.375 g of commercially available green phosphor β-SiAlON:Eu 2+ A green fluorescent glass film slurry was obtained by mixing an organic binder consisting of 1 mL terpineol, 3 mL ethyl acetate, and 1 g ethyl cellulose.

[0063] The other implementation steps are the same as in Example 1.

[0064] The striped composite fluorescent material prepared in this embodiment has a thermal conductivity of 9 W / m². -1 K -1 .

[0065] The obtained composite fluorescent material was encapsulated with a 460nm blue LED chip to obtain a white light source with a correlated color temperature of 4111K, a color rendering index of 92, color coordinates (0.3357, 0.3338), and a luminous efficacy of 139.6 lm / W; and encapsulated with a 460nm blue LD chip to obtain a white light source with a correlated color temperature of 4334K, a color rendering index of 89.9, color coordinates (0.3369, 0.3321), and a luminous efficacy of 168.6 lm / W.

[0066] Example 4

[0067] In this embodiment, the chemical composition of the yellow fluorescent ceramic main structure YAG:Ce fluorescent ceramic is (Y 0.992 Ce 0.008 )3Al5O 12 The weight ratio of green phosphor in the green fluorescent film to red phosphor in the red fluorescent film is 4:1.

[0068] The preparation method of red and green fluorescent glass film paste is as follows: 0.4062g of precursor glass powder and 0.0938g of commercial red phosphor (Sr,Ca)AlSiN3:Eu 2+ A red fluorescent glass film slurry was prepared by mixing an organic binder phase consisting of 0.15 g ethyl cellulose, 150 μL terpineol, and 300 μL ethyl acetate; 0.125 g of precursor glass powder was mixed with 0.375 g of commercially available green phosphor β-SiAlON:Eu 2+ A green fluorescent glass film slurry was obtained by mixing an organic binder consisting of 1 mL terpineol, 3 mL ethyl acetate, and 1 g ethyl cellulose.

[0069] The other implementation steps are the same as in Example 1.

[0070] The striped composite fluorescent material prepared in this embodiment has a thermal conductivity of 7.5 W / m². -1 K -1 .

[0071] The obtained composite fluorescent material was encapsulated with a 460nm blue LED chip to obtain a white light source with a correlated color temperature of 4700K, a color rendering index of 91.2, color coordinates (0.3381, 0.3354), and a luminous efficacy of 136.7 lm / W; and encapsulated with a 460nm blue LD chip to obtain a white light source with a correlated color temperature of 5283K, a color rendering index of 88.6, color coordinates (0.3379, 0.3345), and a luminous efficacy of 162.1 lm / W.

[0072] Example 5

[0073] In this embodiment, the chemical composition of the yellow fluorescent ceramic main structure YAG:Ce fluorescent ceramic is (Y 0.990 Ce 0.010 )3Al5O 12 The weight ratio of green phosphor in the green fluorescent film to red phosphor in the red fluorescent film is 5:1.

[0074] The preparation method of red and green fluorescent glass film paste is as follows: 0.425g of precursor glass powder and 0.075g of commercial red phosphor (Sr,Ca)AlSiN3:Eu 2+A red fluorescent glass film slurry was prepared by mixing an organic binder phase consisting of 0.15 g ethyl cellulose, 150 μL terpineol, and 300 μL ethyl acetate; 0.125 g of precursor glass powder was mixed with 0.375 g of commercially available green phosphor β-SiAlON:Eu 2+ A green fluorescent glass film slurry was obtained by mixing an organic binder consisting of 1 mL terpineol, 3 mL ethyl acetate, and 1 g ethyl cellulose.

[0075] The other implementation steps are the same as in Example 1.

[0076] The striped composite fluorescent material prepared in this embodiment has a thermal conductivity of 8.5 W / m². -1 K -1 .

[0077] The obtained composite fluorescent material was encapsulated with a 460nm blue LED chip to obtain a white light source with a correlated color temperature of 5144K, a color rendering index of 90.1, color coordinates (0.3421, 0.3391), and a luminous efficacy of 132.5 lm / W. Encapsulated with a 460nm blue LD chip, a white light source with a correlated color temperature of 4534K, a color rendering index of 86.9, color coordinates (0.3421, 0.3397), and a luminous efficacy of 159.8 lm / W was obtained. The performance tests of the white LEDs in Examples 1-5 are shown in Table 1.

[0078] Table 1. Performance test results of white LEDs in Examples 1-5

[0079]

[0080] Table 1 shows that by changing the mass ratio of red and green phosphors, the proportion of red-green-blue light in the electroluminescence spectrum of the composite fluorescent material can be effectively controlled, thereby achieving high-quality luminescence. When the mass ratio of red and green phosphors is 1:2, the color quality of the composite fluorescent material is optimal.

[0081] Examples 6-10

[0082] Based on Example 2, while keeping the total area of ​​the red and green fluorescent films unchanged, only the widths of the red and green fluorescent films were adjusted to 1.1, 1.2, 1.3, 1.4, and 1.5 mm, respectively. Other implementation methods were the same as in Example 2. The performance tests of white LEDs in Examples 6-10 are shown in Table 2.

[0083] Table 2. Performance test results of white LEDs in Examples 6-10

[0084]

[0085] As shown in Table 2, as the width of the red and green fluorescent glass films increases, the number of gaps between the red and green films decreases, thereby relatively increasing the area of ​​the red and green films. Therefore, as the width of the phosphor glass film increases, the luminous efficiency, color rendering index, and color temperature also increase.

[0086] Examples 11-14

[0087] Based on Example 2, only the thickness of the YAG:Ce fluorescent ceramic was adjusted to 1.2, 1.4, 1.6, and 1.8 mm; other implementation methods remained the same as in Example 2. The performance tests of white LEDs in Examples 11-14 are shown in Table 3.

[0088] Table 3. Performance test results of white LEDs in Examples 6-10

[0089]

[0090] As shown in Table 3, with the increase of the thickness of YAG:Ce fluorescent ceramic, the luminous efficiency of the composite fluorescent material increases, while the color rendering index and color temperature decrease.

[0091] Comparative Examples 1-5

[0092] Based on Example 1, only the thicknesses of the red and green fluorescent films were adjusted to 60-70, 70-80, 80-90, 100-110, and 120-130 μm, respectively; other implementation methods remained the same as in Example 1. The performance tests of the white LEDs in Comparative Examples 1-5 are shown in Table 4.

[0093] Table 4. Performance test results of white LEDs in Comparative Examples 1-5

[0094]

[0095] As shown in Table 4, with the increase of the thickness of the red and green fluorescent glass film, the total fluorescent material increases, and thus the luminous efficiency increases accordingly. However, with the increase of thickness, the red-green-blue ratio in the electroluminescence spectrum of the composite fluorescent material becomes unbalanced, and thus the color rendering index shows a downward trend.

[0096] Comparative Example 6

[0097] The ceramic material prepared by the method in Chinese invention patent CN113979739A achieved a luminous efficiency of 102 lm / W and a color rendering index of 74 under blue LED excitation. The performance tests of white LEDs in Examples 1-10 and Comparative Examples 1-6 are shown in Table 5.

[0098] Table 5. Performance test results of white LEDs in Examples 1-10 and Comparative Examples 1-6

[0099]

[0100]

[0101] As shown in Table 5, the striped composite fluorescent material provided by this invention effectively avoids the photon reabsorption effect caused by the stacking or mixing of red and green fluorescent materials into multi-color fluorescent films, thus mitigating the "photometric-chromaticity contradiction" to a certain extent. Simultaneously, the composite fluorescent material prepared by this structure improves the heat transfer process, effectively avoiding heat accumulation under high-power LDs. Furthermore, the red and green fluorescent glass films coated on YAG:Ce fluorescent ceramics using this structure effectively improve the blue light effect in white LED / laser lighting and compensate for the insufficient red light of YAG:Ce fluorescent materials, thereby achieving high-quality luminescence. Compared with existing technologies, the composite fluorescent material of this invention possesses excellent optical and thermal properties, and because the spot area of ​​the blue LD is ≤2mm... 2 The thickness of the film prepared by the technology used in this invention can reach 1 mm, so it can be applied to white LED / LD lighting.

[0102] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A striped composite fluorescent material, characterized in that, The striped composite fluorescent material consists of a yellow fluorescent ceramic main structure and a layer of alternating red and green fluorescent glass films of equal width and thickness coated on the upper surface of the yellow fluorescent ceramic main structure. The thickness of the yellow fluorescent ceramic is 1-1.8 mm, and the thickness of the red and green fluorescent glass films is 50-60 μm, and the width of the red and green fluorescent glass films is 1-1.5 mm. The chemical composition of the yellow fluorescent ceramic main structure is (Y). 1-x Ce x )3Al5O 12 0.001≤x≤0.01; The phosphor used in the red fluorescent glass film is (Sr,Ca)AlSiN3:Eu 2+ The phosphor used in the green fluorescent glass film is β-SiAlON:Eu. 2+ .

2. The striped composite fluorescent material according to claim 1, characterized in that, The yellow fluorescent ceramic is garnet ceramic (Y). 1-x Ce x )3Al5O 12 Ce 3+ The ion concentration is 0.2 at%-1.0 at%, and the weight ratio of green phosphor in the green fluorescent glass film to red phosphor in the red fluorescent glass film is (1-5):

1.

3. The striped composite fluorescent material according to claim 1, characterized in that, The phosphor used in the red fluorescent glass film has a particle size of 200nm-250nm; the phosphor used in the green fluorescent glass film has a particle size of 200nm-250nm.

4. The method for preparing the striped composite fluorescent material according to any one of claims 1-3, characterized in that, Yellow fluorescent ceramics (Y) were prepared using a solid-state reaction method combined with vacuum sintering technology. 1-x Ce x )3Al5O 12 The fluorescent ceramic sheet is YAG:Ce fluorescent ceramic. Then, a paste of red and green fluorescent glass films is coated onto the surface of the yellow fluorescent ceramic using a doctor blade. The striped composite fluorescent material is then prepared using a low-temperature sintering technique, specifically including the following steps: (1) YAG:Ce fluorescent ceramics were prepared using solid-state reaction technology; (2) After coating the gel-state red and green fluorescent glass films onto YAG:Ce fluorescent ceramics using a mold, striped composite fluorescent materials are obtained by low-temperature sintering technology.

5. The method for preparing the striped composite fluorescent material according to claim 4, characterized in that, The preparation method of YAG:Ce fluorescent ceramic in step (1) is as follows: ①According to the stoichiometric formula (Y 1-x Ce x )3Al5O 12 The required powder raw materials, namely Al2O3, Y2O3 and CeO2, were accurately weighed with a ratio of 0.001≤x≤0.

01. They were then placed in a nylon ball mill jar for planetary ball milling for 15-25 hours. The ball milling speed was set to 200 r / min, the ball milling beads were Al2O3 balls, and the ball milling medium was anhydrous ethanol. The slurry after ball milling was poured into an evaporating dish and placed in an 80℃ electric heating drying oven for 24 hours. After that, it was passed through a 200-mesh sieve 5 times to obtain a mixed powder. ② The mixed powder is placed in a stainless steel mold with a diameter of 22mm, and unidirectional pressure is applied to it by a press to make it into a green blank with a certain strength. The applied pressure is 20 MPa and the holding time is 5 min. After the dry-pressed green blank is packaged, it is placed in a cold isostatic press for cold isostatic pressing treatment. The holding pressure is 300 MPa and the holding time is 300 s. The obtained green blank is calcined in an air atmosphere in a muffle furnace at 800-900℃ for 10 h to remove impurities. ③ The cleaned green billet is placed in a vacuum tungsten filament furnace at 1765℃ and 5×10⁻⁶℃. -4 After sintering under a vacuum of Pa for 10 h, the ceramic was annealed in air at 1450℃ for 10 h. The annealed ceramic was then polished on both sides to 1 mm to obtain YAG:Ce fluorescent ceramic.

6. The method for preparing the striped composite fluorescent material according to claim 4, characterized in that, The preparation method of the striped composite fluorescent material in step (2) is as follows: ① The required powder raw materials were accurately weighed using an analytical balance according to the stoichiometric formula 38SiO2-40B2O3-4ZnO-4Na2O-3Al2O3-1Li2O, which is SiO2, B2O3, ZnO, Na2O, Al2O3 and Li2O. The powder raw materials were then placed in an agate mortar and ground thoroughly. The ground mixed powder was poured into an alumina crucible and sintered in a high-temperature furnace at 1300℃ for 2 hours to obtain a molten liquid. The molten liquid was then poured into a copper mold and cooled to obtain a precursor glass block. Finally, the precursor glass block was ground into powder and passed through a 100-mesh sieve to obtain precursor glass powder. ② The precursor glass powder is mixed with commercial (Sr,Ca)AlSiN3:Eu 2+ A red fluorescent glass film slurry was prepared by mixing red phosphor and organic binder. The precursor glass powder was then mixed with commercially available (Sr,Ca)AlSiN3:Eu... 2+ Based on a total phosphor mass of 0.5g, the organic binder consisted of 0.15g ethyl cellulose, 150μL terpineol, and 300μL ethyl acetate. The precursor glass powder was then mixed with commercially available β-SiAlON:Eu 2+ Green phosphor is mixed with organic binder to obtain green fluorescent glass film slurry, and precursor glass powder is mixed with commercial β-SiAlON:Eu 2+ Based on a total mass of 0.5g of green phosphor, the composition of the organic binder is: 0.15g ethyl cellulose, 150μL terpineol, and 300μL ethyl acetate; wherein, the weight ratio of green phosphor to precursor glass powder is 3:1, and the weight ratio of green phosphor to red phosphor is (1-5):

1. ③ Place the 3D printing mold on the YAG:Ce fluorescent ceramic sheet and fix it to the glass substrate with tape. Apply red fluorescent glass film slurry to the YAG:Ce ceramic sheet using a scraper through the 3D printing mold. Dry in a 150℃ electric heating drying oven for 3 hours. Then, move the 3D printing mold on the YAG:Ce fluorescent ceramic sheet by the width of the red fluorescent film and fix it to the glass substrate again. Apply green fluorescent glass film slurry to the YAG:Ce ceramic sheet using a scraper through the 3D printing mold. Dry in a 150℃ electric heating drying oven for 3 hours. The resulting composite fluorescent material is sintered to obtain a striped composite fluorescent material.

7. The method for preparing the striped composite fluorescent material according to claim 4 or 6, characterized in that, The sintering process is as follows: hold at 120℃-130℃ for 0.5h-1h, hold at 400℃-450℃ for 0.5h-1h, and after the holding is completed, cool the sample to room temperature in an argon atmosphere.

8. The application of the striped composite structure fluorescent material according to any one of claims 1-3 in the field of fluorescence conversion white LED / LD lighting, characterized in that: When applied to white LED lighting devices, the excitation source is a blue LED chip; when applied to white LD lighting devices, the excitation source is a blue LD chip.

9. The application according to claim 8, characterized in that: When excited by a 450-460 nm blue LED / LD chip, a white LED / LD with a color temperature of 3000-6000K, a color rendering index of 86-94, and a luminous efficiency of 140-180 lm / W is obtained.

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