A blue-green light fluorescence converter, a preparation method and application thereof

Abstract

The application provides a blue-green light fluorescent converter, and belongs to the technical field of inorganic luminescent materials. 3‑x‑y Ce x A y )Sc2Si3O 12 , wherein A is one or more of alkali metal elements Li, Na and K, 0.04<=x<=0.08, 0.03<=y<=0.12; the high-refractive glass powder has a refractive index of 1.66-1.86 at 510 nm, and contains one or more of PbO, WO3, TeO2 and Sb2O3, and one or more of alkali metal oxides Na2O, Li2O and K2O. The application further provides a preparation method and application of the converter. The blue-green light fluorescent converter has low preparation temperature, short preparation period, good fluorescent thermal stability, can bear high-power density laser irradiation, emits wideband blue-green light with a wave peak at 505-520 nm under blue light excitation at 430-460 nm, effectively fills the "blue-green light depression", has high transmittance, improves fluorescent efficiency, and has a quantum efficiency greater than 85%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of inorganic luminescent materials, and relates to a blue-green light fluorescent converter, a preparation method and application thereof. BACKGROUND

[0002] With the increasingly prominent problems of environmental pollution and resource shortage in the world, semiconductor solid-state lighting is gradually replacing traditional lighting sources due to its high energy efficiency, energy saving and environmental protection, and is known as the green lighting source in the 21st century. Light-emitting diodes (LEDs) and semiconductor lasers (LDs) are two common semiconductor devices. White light LED lighting based on blue light LED chips exciting fluorescent powder has been widely used in various lighting fields after years of development. LD is another semiconductor light-emitting device, which has the advantages of high brightness, low beam divergence and higher light efficiency at high power density compared to LED. Laser lighting based on LD is particularly suitable for high-brightness directional lighting fields (such as laser car lights, projection display, etc.). At present, semiconductor solid-state lighting is developing towards high power and high brightness. Existing high-power LED lighting and semiconductor LD lighting are both realized by exciting all-inorganic fluorescent bodies such as fluorescent ceramic, fluorescent glass and fluorescent film through blue light LED or blue light LED as laser light source, but the spectrum lacks blue-green light component around 500 nm, forming the well-known "blue-green light dip", and the color rendering index of the light source is less than 70, which cannot meet the demand of high color rendering high-power lighting. Although Chinese patents (CN102730980B, CN110642624A, CN110668803A) disclose a preparation method of transparent blue-green light transparent ceramic, the preparation process of the transparent ceramic is complex, requires high equipment, needs long time high-temperature sintering, the equipment is expensive, and the preparation cost is high, which is not conducive to large-scale production and promotion.

[0003] The spectrum of existing high-power LED and laser lighting lacks blue-green light component, forming the well-known "blue-green light dip", and the color rendering index of the light source is less than 70, which cannot meet the demand of high color rendering high-power lighting. In addition, the existing fluorescent film has a large difference in refractive index between glass, fluorescent powder and substrate, and there is total reflection loss and scattering loss at the interface. For short-wavelength blue-green light, this loss is more serious, resulting in low transmittance of the fluorescent film and reducing the fluorescent extraction efficiency of the film, which cannot obtain a high-efficiency fluorescent converter.

[0004] Therefore, it is urgent to study a blue-green light fluorescent converter to solve the technical problems of "blue-green light dip" and low fluorescent extraction efficiency in the prior art, so as to meet the demand of high energy efficiency, high color rendering and high-power LED lighting and laser lighting. SUMMARY

[0005] In view of the above, the present application provides a blue-green light fluorescent converter and a preparation method and application thereof, which can emit broadband blue-green light with a peak at 505-520 nm under blue light excitation at 430-460 nm, effectively filling the "blue-green light gap"; the refractive indexes of the substrate, high-refractive-index glass powder and scandium calcium silicate fluorescent powder match each other, which can reduce the refraction and scattering loss of light at the contact interface, maintain high transmittance of the fluorescent converter and improve the fluorescent efficiency of the fluorescent converter, with a quantum efficiency greater than 85%.

[0006] To achieve the above object, the present application provides a blue-green light fluorescent converter, comprising a substrate and a fluorescent powder layer bonded to the substrate; the fluorescent powder layer is composed of high-refractive-index glass powder and scandium calcium silicate fluorescent powder.

[0007] The particle size of the scandium calcium silicate fluorescent powder is 2-20 µm, and the chemical formula is (Ca 3-x-y Ce x A y )Sc2 Si3O 12 wherein A is one or more of alkali metal elements Li, Na and K, 0.04≤x≤0.08 and 0.03≤y≤0.12.

[0008] The refractive index of the high-refractive-index glass powder at 510 nm is 1.66-1.86, and the components contain one or more of PbO, WO3, TeO2 and Sb2O3, and one or more of alkali metal oxides Na2O, Li2O and K2O.

[0009] The blue-green light fluorescent converter emits broadband blue-green light with a peak at 505-520 nm under blue light excitation at 430-460 nm.

[0010] Further, the refractive indexes of the substrate, high-refractive-index glass powder and scandium calcium silicate fluorescent powder match each other, and the maximum refractive index difference between any two of them is less than 0.1.

[0011] Further, the refractive index of the substrate at 510 nm is 1.66-1.86, and the substrate is made of any one of sapphire, transparent ceramic and transparent glass; the thickness is 0.05-1.0 mm.

[0012] Further, the substrate is made of sapphire, and the surface of the sapphire is sequentially coated with an anti-reflection film and a band-pass film.

[0013] Further, the content of the scandium calcium silicate fluorescent powder in the fluorescent powder layer is 10-90 wt%.

[0014] Further, the content of the scandium calcium silicate fluorescent powder in the fluorescent powder layer is 40-60 wt%.

[0015] Further, the thickness of the fluorescent powder layer is 20-200 microns.

[0016] Further, the thickness of the fluorescent powder layer is 50-100 microns.

[0017] The application further provides a preparation method of the blue-green light fluorescent converter as described above, comprising the following steps:

[0018] S1: according to the stoichiometric ratio of chemical formula (Ca 3-x-y Ce x A y )Sc2 Si3O 12 , the oxides or salts of each element are weighed and ground, and are fully calcined and ground in air or reducing atmosphere to obtain the calcium scandium silicate fluorescent powder;

[0019] S2: the high-refractive glass powder, the calcium scandium silicate fluorescent powder obtained in step S1 and an organic solvent are uniformly mixed and then coated on a clean substrate, and then dried in an oven;

[0020] S3: then, the substrate is placed in a muffle furnace and subjected to heat treatment at 400-800 DEG C for 10-60 min to obtain the blue-green light fluorescent converter.

[0021] The application further provides an application of the blue-green light fluorescent converter as described above in LED lighting and laser lighting.

[0022] The application has the following advantages by adopting the above technical solution:

[0023] The blue-green light fluorescent converter of the application uses high-refractive glass powder and calcium scandium silicate fluorescent powder as raw materials, can emit broadband blue-green light with a wave peak at 505-520 nm under the excitation of blue light at 430-460 nm, effectively fills the "blue-green light depression", and has a high transmittance and a quantum efficiency greater than 85%. In addition, the fluorescent converter of the application has a low preparation temperature and does not need long-time heat preservation, which is beneficial to mass production. The surface of the fluorescent converter of the application is coated with commercial red powder, and high-color white light can be obtained under the excitation of blue light, and the color rendering index of the light source is greater than 90. The application can effectively solve the problem of "blue-green light depression" and realize high-energy-efficiency high-color large-power LED lighting and laser lighting. BRIEF DESCRIPTION OF DRAWINGS

[0024] 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.

[0025] Figure 1 The XRD patterns of the blue-green phosphor converter, phosphor, and glass powder in Example 1 are shown below.

[0026] Figure 2 The emission and excitation spectra of the blue-green phosphor converter in Example 1 are shown.

[0027] Figure 3 The transmittance curve of the blue-green phosphor in Example 1;

[0028] Figure 4 The normalized fluorescence intensity of the blue-green phosphor converter in Example 1 at different temperatures;

[0029] Figure 5 The emission spectrum of the blue-green phosphor converter and the 452nm blue LD packaged device in Example 1;

[0030] Figure 6 The parameter curves for the blue-green phosphor converter and the 452nm blue LD packaged device in Example 1 are shown.

[0031] Figure 7 The blue-green phosphor converter in Example 1 is coated with CaAlSiN3:Eu 2+ The emission spectrum and parameters of the device packaged with red phosphor and a 452nm blue LD;

[0032] Figure 8 The blue-green phosphor converter in Example 1 is coated with CaAlSiN3:Eu 2+ The emission spectrum and parameters of a device packaged with a red phosphor and a 450nm blue LED chip. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The application provides a blue-green light fluorescent converter, which comprises a substrate and a fluorescent powder layer bonded to the substrate; the fluorescent powder layer comprises high-refractive-index glass powder and scandium calcium silicate fluorescent powder.

[0035] The chemical formula of the scandium calcium silicate fluorescent powder is (Ca 3-x-y Ce x A y )Sc2 Si3O 12 wherein A is one or more of alkali metal elements Li, Na and K, 0.04<=x<=0.08 and 0.03<=y<=0.12.

[0036] The high-refractive-index glass powder has a refractive index of 1.66-1.76 at 510 nm, and contains one or more of PbO, WO3, TeO2 and Sb2O3, and one or more of alkali metal oxides Na2O, Li2O and K2O.

[0037] The blue-green light fluorescent converter emits broadband blue-green light with a peak at 505-520 nm under excitation of blue light with a wavelength of 430-460 nm.

[0038] The refractive indexes of the substrate, the high-refractive-index glass powder and the scandium calcium silicate fluorescent powder are matched with each other, and the maximum refractive index difference between any two of them is less than 0.1. The substrate is made of any one of sapphire, transparent ceramic and transparent glass, and has a thickness of 0.05-1.0 mm. The substrate is preferably made of sapphire, and the surface of the sapphire is coated with an antireflection film and a band-pass film in sequence. The content of the scandium calcium silicate fluorescent powder in the fluorescent powder layer is 10-90 wt%, preferably 40-60 wt%. The thickness of the fluorescent powder layer is 20-200 microns, preferably 50-100 microns.

[0039] The application further provides a preparation method of the blue-green light fluorescent converter.

[0040] S1: oxides or salts corresponding to each element are weighed according to the stoichiometric ratio of the chemical formula (Ca 3-x-y Ce x A y )Sc2 Si3O 12 , and are ground, and are fully calcined and ground in air or a reducing atmosphere to obtain scandium calcium silicate fluorescent powder;

[0041] S2: the high-refractive-index glass powder, the scandium calcium silicate fluorescent powder obtained in step S1 and an organic solvent are mixed uniformly, and are coated on a clean substrate, and then are placed in an oven for drying;

[0042] S3: then, the substrate is placed in a muffle furnace for heat treatment at 400-800 DEG C for 10-60 min to obtain the blue-green light fluorescent converter.

[0043] The application also provides application of the blue-green light fluorescent converter in LED lighting and laser lighting.

[0044] Example 1

[0045] The preparation process of the blue-green light fluorescent converter is as follows:

[0046] S1: CaCO3, NaHCO3, CeO2, Sc2O3 and SiO2 are weighed according to the stoichiometric ratio, uniformly ground in a mortar, and then put into a corundum crucible and treated at 1360°C for 6h in a tube furnace with nitrogen-hydrogen mixed gas. After grinding, the average particle size of the calcium scandium silicate fluorescent powder obtained is 10μm; 2.88 Ce 0.06 Na 0.06 Sc2Si3O 12 Chemical stoichiometric ratio CaCO3, NaHCO3, CeO2, Sc2O3, SiO2, uniformly ground in a mortar, and then put into a corundum crucible and treated at 1360°C for 6h in a tube furnace with nitrogen-hydrogen mixed gas. After grinding, the average particle size of the calcium scandium silicate fluorescent powder obtained is 10μm;

[0047] S2: The organic solvent, glass powder and calcium scandium silicate fluorescent powder are uniformly mixed according to the mass ratio of 1:2.4:1.6, and then scraped on a sapphire substrate and dried in a 60°C oven for 12h; wherein the components of the glass powder are 11WO3-26B2O3-35ZnO-12SiO2-10La2O3-6Li2O, the refractive index of the glass powder at 510nm is 1.73, and the particle size of the glass powder is 20μm; the organic solvent is pine oil alcohol containing 3% ethyl cellulose;

[0048] S3: Then put into a muffle furnace and heat treated at 640°C for 40min to obtain a blue-green light fluorescent converter with a fluorescent powder layer thickness of 73μm.

[0049] The quantum efficiency of the calcium scandium silicate fluorescent powder prepared in step S1 in this example is 83%, and the fluorescent performance of the calcium scandium silicate fluorescent powder does not decrease during the sintering process to prepare the blue-green light fluorescent converter. Since the refractive indexes of the substrate, glass and fluorescent powder are matched with each other, the refractive loss is reduced, and the quantum efficiency of the blue-green light fluorescent converter is increased to 91%.

[0050] Example 2

[0051] The preparation process of the blue-green light fluorescent converter is as follows:

[0052] S1: CaCO3, NaHCO3, CeO2, Sc2O3 and SiO2 are weighed according to the stoichiometric ratio, uniformly ground in a mortar, and then put into a corundum crucible and treated at 1360°C for 6h in a tube furnace with nitrogen-hydrogen mixed gas. After grinding, the average particle size of the calcium scandium silicate fluorescent powder obtained is 10μm; 2.94 Ce 0.04 Li 0.06 Sc 1.9 Si3O 12CaCO3, Li2CO3, CeO2, Sc2O3, SiO2 were weighed in stoichiometric ratio, and were ground in a mortar to homogeneity. The mixture was put into a corundum crucible and was heat-treated at 1320℃ for 6h in a tube furnace under nitrogen-hydrogen mixed gas. After grinding, the average particle size of the calcium scandium silicate phosphor was 8μm;

[0053] S2: The organic solvent, glass powder, and calcium scandium silicate phosphor were mixed in a mass ratio of 1:2.4:1.6, and were stirred to homogeneity. The mixture was blade-coated on a sapphire substrate, and was dried in an oven at 60℃ for 12h. The glass powder was composed of 55TeO2-10SiO2-18ZnO-13Na2O-4B2O3, and had a refractive index of 1.80 at 510nm and a particle size of 10μm. The organic solvent was terpineol containing 3% ethyl cellulose;

[0054] S3: The mixture was then heat-treated at 550℃ for 10min in a muffle furnace, to obtain a blue-green fluorescent converter with a phosphor layer thickness of 100μm.

[0055] Figure 1 The XRD spectra of the blue-green fluorescent converter, phosphor, and glass powder of Example 1 are shown in the figure. It can be seen that the phosphor is a pure garnet structure, the glass powder is amorphous, and the fluorescent converter is composed of amorphous glass powder and pure garnet structure phosphor, and does not contain other impurities.

[0056] Figure 2 The emission and excitation spectra of the blue-green fluorescent converter of Example 1 are shown in the figure. It can be seen that the fluorescent converter can emit broadband blue-green light with a peak at 508nm under blue light excitation at 430-460nm.

[0057] Figure 3 The transmittance curve of the blue-green fluorescent converter of Example 1 is shown in the figure. It can be seen that when the content of the phosphor in the fluorescent converter is 40%, and the thickness of the phosphor layer is 73μm, the transmittance of the fluorescent converter at 508nm is 49%, and the fluorescent converter has strong absorption of blue light. The refractive indices of the substrate, phosphor, and glass powder match each other, which can effectively improve the transmittance of the fluorescent converter, and further improve the quantum efficiency of the fluorescent converter.

[0058] Figure 4 The normalized fluorescence intensity of the blue-green fluorescent converter of Example 1 at different temperatures is shown in the figure. It can be seen that the fluorescence intensity of the fluorescent converter at 150℃ is 91% of that at room temperature, and at 200℃ it remains at 87% of that at room temperature.

[0059] Figure 5 and Figure 6The luminescence spectrum and parameter curve of the packaged device of the blue-green fluorescence converter and the 452 nm blue light LD in Example 1 are shown in the figure, it can be seen from the figure that the luminescence spectrum of the device covers the blue light and blue-green light regions; with the increase of the laser power, the luminous flux of the device gradually increases; under the excitation of the blue light with the power of 5.5 W, the laser spot area is 0.43 mm 2 , and the corresponding excitation density is 12.8 W / mm 2 ; the device has not reached the fluorescence saturation, and the high luminance blue-green light with the luminance of 701 lm is generated, which shows that the fluorescence converter can bear the high-power density laser irradiation.

[0060] Figure 7 The luminescence spectrum and parameter of the packaged device of the blue-green fluorescence converter coated with CaAlSiN3:Eu 2+ red fluorescence powder in Example 1 and the 452 nm blue light LD are shown in the figure, it can be seen from the figure that the power of the blue light LD in the laser illumination device is 2.19 W, the laser spot area is 0.43 mm 2 , and the corresponding excitation density is 5.1 W / mm 2 ; the white light with the luminance of 257 lm is generated, and the color rendering index is 93.

[0061] Figure 8 The luminescence spectrum and parameter of the packaged device of the blue-green fluorescence converter coated with CaAlSiN3:Eu 2+ red fluorescence powder in Example 1 and the 450 nm blue light LED chip are shown in the figure, it can be seen from the figure that the spectrum of the LED illumination device covers the blue light, green light, yellow light and red light regions; when the working current of the LED chip is 500 mA, the white light with the luminance of 625 lm is generated, the luminous efficiency is 121 lm / W, the color rendering index is 97, and the color temperature is 5646 K.

[0062] The blue-green fluorescence converter of the application uses high-refractive-index glass powder and scandium calcium silicate fluorescent powder as raw materials, can emit broadband blue-green light with the wave peak located at 505-520 nm under the excitation of 430-460 nm blue light, effectively fills the “blue-green light depression”, the refractive indexes of the substrate, the high-refractive-index glass powder and the scandium calcium silicate fluorescent powder are matched with each other, the refraction and scattering loss of light at the contact interface can be reduced, the fluorescence converter can maintain high transmittance, and the fluorescence efficiency of the fluorescence converter is improved, and the quantum efficiency is greater than 85%. The commercial red powder is coated on the surface of the fluorescence converter, high-color-rendering white light can be obtained under the excitation of blue light, and the color rendering index of the light source is greater than 90. The application can effectively solve the “blue-green light depression” problem, and realize high-energy-efficiency high-color-rendering large-power LED illumination and laser illumination.

[0063] The above merely describes preferred embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A blue-green phosphor conversion body, characterized in that The substrate and the phosphor layer adhered to the substrate; the phosphor layer is composed of high refractive index glass powder and scandium calcium silicate phosphor; The average particle size of the calcium scandium silicate fluorescent powder is 10 μm, and the chemical formula is Ca 2.88 Ce 0.06 Na 0.06 Sc2Si3O 12 The refractive index of the high refractive index glass powder at 510 nm is 1.73, and the composition is 11 WO3-26 B2O3-35 ZnO-12 SiO2-10 La2O3-6 Li2O; the preparation process of the blue-green light fluorescent converter is as follows: S1: according to Ca 2.88 Ce 0.06 Na 0.06 Sc2Si3O 12 CaCO3, NaHCO3, CeO2, Sc2O3, SiO2 are weighed according to the stoichiometric ratio, uniformly ground in a mortar, and then put into a corundum crucible, and then heat-treated at 1360℃ for 6h in a tubular furnace with nitrogen-hydrogen mixed gas. After grinding, the average particle size of the calcium scandium silicate fluorescent powder is 10μm. S2: the organic solvent, the glass powder, and the scandium calcium silicate phosphor are stirred and mixed uniformly at a mass ratio of 1:2.4:1.6, and then are coated on the substrate and dried in an oven at 60℃ for 12 hours; wherein the component of the glass powder is 11WO3-26B2O3-35ZnO-12SiO2-10La2O3-6Li2O, the refractive index of the glass powder at 510nm is 1.73, and the particle size of the glass powder is 20μm; the organic solvent is pine oil alcohol containing 3% ethyl cellulose; S3: then the substrate is placed in a muffle furnace and heat-treated at 640℃ for 40min to obtain the blue-green light phosphor conversion body with a phosphor layer thickness of 73μm; The substrate is sapphire; The blue-green light phosphor conversion body emits broadband blue-green light with a peak at 508nm under the excitation of blue light at 430-460nm; The refractive indexes of the substrate, the high refractive index glass powder, and the scandium calcium silicate phosphor are matched with each other, and the maximum refractive index difference between any two of them is less than 0.

1.

2. The blue-green phosphor conversion body according to claim 1, characterized in that The thickness of the substrate is 0.05-1.0mm.

3. The blue-green phosphor conversion body according to claim 2, characterized in that The surface of the sapphire substrate is coated with an antireflection film and a bandpass film in sequence.

4. A method of producing a blue-green fluorescent converter as claimed in any one of claims 1 to 3, characterized in that The method comprises the following steps: S1: according to Ca 2.88 Ce 0.06 Na 0.06 Sc2Si3O 12 CaCO3, NaHCO3, CeO2, Sc2O3, SiO2 are weighed according to the stoichiometric ratio, uniformly ground in a mortar, and then put into a corundum crucible, and then heat-treated at 1360°C for 6h in a tube furnace with nitrogen-hydrogen mixed gas. After grinding, the average particle size of the calcium scandium silicate fluorescent powder is 10μm. S2: the organic solvent, the glass powder, and the scandium calcium silicate phosphor are stirred and mixed uniformly at a mass ratio of 1:2.4:1.6, and then are coated on the sapphire substrate and dried in an oven at 60℃ for 12 hours; wherein the component of the glass powder is 11WO3-26B2O3-35ZnO-12SiO2-10La2O3-6Li2O, the refractive index of the glass powder at 510nm is 1.73, and the particle size of the glass powder is 20μm; the organic solvent is pine oil alcohol containing 3% ethyl cellulose; S3: then the substrate is placed in a muffle furnace and heat-treated at 640℃ for 40min to obtain the blue-green light phosphor conversion body with a phosphor layer thickness of 73μm.

5. The blue-green light phosphor conversion body according to any one of claims 1-3 is applied in LED lighting and laser lighting.

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