Preparation method of Eu < 2 + >-doped fluorescent glass ceramic

Abstract

The invention discloses a preparation method of Eu < 2 + > doped fluorescent glass ceramic. The preparation method comprises the following steps: uniformly mixing Eu < 2 + >-doped fluorescent powder and glass powder in an organic solvent, drying to remove the organic solvent, and sieving to obtain a precursor mixture; carrying out dry pressing and shaping on the precursor mixture, and carrying out cold isostatic pressing to obtain a fluorescent glass ceramic biscuit; and carrying out densification sintering on the fluorescent glass ceramic biscuit on a Joule hot sintering device for 5-60 seconds under the conditions of 30-60 V and 15-30 A in a mixed atmosphere of hydrogen and nitrogen, cooling, and taking out to obtain the Eu < 2 + > doped fluorescent glass ceramic. The method is short in synthesis time, simple in process, low in manufacturing cost and easy to implement on a large scale; the obtained Eu < 2 + >-doped fluorescent glass ceramic has high luminous efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent materials, and particularly relates to a preparation method of Eu 2+ -doped fluorescent glass ceramics. Background Art

[0002] In recent years, solid-state light source technology in China has developed vigorously. As a key material in solid-state light source technology, the main function of the fluorescence conversion material is to absorb the excitation light of the semiconductor diode chip and convert it into light of other wavelengths. The performance of the fluorescence conversion material directly determines the performance of the solid-state light source, such as the color rendering index, lumen efficiency, and reliability. Currently, the most widely used fluorescence conversion material is an organic composite material obtained by encapsulating fluorescent powder with silica gel / epoxy resin. Assembling it with a blue light-emitting diode (LED) results in a white light-emitting device (pc-WLED). However, such polymer materials have obvious defects. Their thermal conductivity is extremely poor, with a thermal conductivity only between 0.1 - 0.4 W / m / K, and their heat resistance is not ideal, generally requiring an operating temperature below 150°C. During the operation of the pc-WLED, the device continuously generates heat. Since these resin-encapsulated fluorescent powders cannot effectively dissipate heat, the temperature inside the device continues to rise, leading to a series of serious problems, such as the phenomenon of light decay in the pc-WLED, where the luminous intensity gradually decreases, and the problem of color deviation, where the white light emitted deviates from the standard value, seriously affecting the lighting and display effects. In addition, there is an "efficiency roll-off" phenomenon when the LED outputs at high power, which limits the further improvement of its brightness and makes it difficult to meet the requirements of high-brightness lighting and display applications. The laser diode (LD) does not have the "efficiency roll-off" phenomenon, so its power density is much higher than that of the LED, and it is developing into a new generation of solid-state light sources. A laser-driven light-emitting device (pc-LD) assembled with garnet-type Y3Al5O 12 :Ce 3+ fluorescent glass ceramics has achieved commercial success and brought a new revolution to the light source field.

[0003] When meeting the stringent requirements of LD, all-inorganic fluorescence conversion materials that can withstand its irradiation and have high thermal conductivity, such as single crystals (such as Chinese invention patent documents CN100389604C, CN112080798A), transparent ceramics (such as Chinese invention patent documents CN117049861A, CN111039660A), and glass ceramics (such as Chinese invention patent documents CN115432924A, CN115893858A, CN116282937A), have been developed one after another. Although single crystals and transparent ceramics have high thermal conductivity and excellent physical and chemical stability, their preparation processes are complex and costly, making it difficult to achieve large-scale mass production. Fluorescent glass ceramics have become a research hotspot due to their high luminous efficiency, relatively simple manufacturing process, and low cost. Currently, the main preparation method is to mix fluorescent powder with multi-component low-melting glass powder in a specific ratio and then co-fire them at a low temperature. However, due to Eu 2+ -doped fluorescent powder is easily eroded by the glass melt phase during sintering, resulting in the decomposition and failure of the fluorescent powder, or Eu 2+ is oxidized and its valence changes to Eu 3+ affecting the light color. Therefore, it is necessary to optimize the sintering method of the fluorescent powder and the low-melting glass powder. Xia et al. used the glass melt stirring method to disperse the fluorescent powder in the glass matrix within a few seconds and then rapidly quench it to obtain highly efficient fluorescent glass ceramics (Chinese invention patent document CN117945652A). Wang et al. used an infrared radiation sintering furnace to prepare a fluorescent glass film material within dozens of seconds. The luminous efficiency of this fluorescent glass film material is 10-40% higher than that of the traditional low-temperature co-firing method (Chinese invention patent CN118291138A). It shows that on the premise of sintering the fluorescent powder and glass composite material densely, shortening the sintering time to the second level can effectively avoid the loss of photoluminescence efficiency caused by the erosion of the fluorescent powder by the glass amorphous phase. However, the sintering equipment (muffle furnace and infrared radiation sintering furnace) required for the above two synthesis methods are both heavy equipment, with high costs and large operation limitations. In 2020, Hu et al. from the University of Maryland reported a low-cost Joule heating sintering device, which mainly consists of two pieces of carbon felt connected to a DC power supply (Wang C, Ping W, Hu L, et al. A general method to synthesize and sinter bulk ceramics in seconds[J], Science, 2020, 368, 521-526, DOI: 10.1126 / science.aaz7681). Subsequently, Ding et al. used this Joule heating device to synthesize a Y3Al5O 12 :Ce 3 +Based on the fluorescent glass ceramic material, its luminous efficiency reaches up to 164.24 lm / W (Liang Y, Ding X, Yan C, et al. Phosphor-in-glass (PIG) converter sintered by a fast Joule heating process for high-power laser-driven white lighting [J]. Optics Express, 2021, 29(10): 14218-14230.). Due to Eu 2+ The doped fluorescent material has less structural rigidity than Y3Al5O 12 :Ce 3+ phosphor under the same conditions. The reasons involve many factors such as crystal structure, chemical bond characteristics, doping ion stability, and environmental adaptability. Y3Al5O 12 :Ce 3+ phosphor has a highly symmetric cubic garnet structure, is not prone to phase transformation, and Ce 3+ has a high matching degree with the host and a low oxidation tendency. While Eu 2+ -doped fluorescent materials take CaAlSiN3:Eu 2+ phosphor as an example. It belongs to a hexagonal structure, has significant distortion, is prone to phase transformation, and Eu 2+ is easily oxidized to Eu 3+ , and the lattice relaxation is obvious at high temperatures and is easily damaged by heat. Therefore, it is relatively easy to synthesize fluorescent glass ceramics based on Y3Al5O 12 :Ce 3+ . However, synthesizing high-performance Eu 2+ -doped fluorescent glass ceramic materials has always been the direction of research by researchers. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a preparation method of Eu 2+ -doped fluorescent glass ceramics to solve the problem of unsatisfactory luminous efficiency of Eu 2+ -doped fluorescent glass ceramics in the existing technology. The Eu 2+ -doped fluorescent glass ceramics prepared by the present invention can be excited by near-ultraviolet light and used on a near-ultraviolet laser device, thereby replacing the blue laser-driven white laser illumination source, eliminating the excessive laser blue hazard, and supplementing the missing blue light, red light and other bands in the white laser light source to improve the color rendering performance of the white laser illumination source.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a Eu 2+Preparation method of doped fluorescent glass ceramics, comprising the following steps:

[0007] S1. Mixing of precursor raw materials: Mix the Eu 2+ -doped fluorescent powder and glass powder evenly in an organic solvent, dry to remove the organic solvent, and sieve to obtain a precursor mixture;

[0008] S2. Molding of precursor raw materials: Dry-press and shape the precursor mixture obtained in step S1, and cold isostatically press to obtain a green body of fluorescent glass ceramics;

[0009] S3. Sintering: Under a mixed atmosphere of hydrogen and nitrogen, perform densification sintering on the green body of fluorescent glass ceramics obtained in step S2 on a Joule heat sintering device at 30 - 60 V and 15 - 30 A for 5 - 60 s, cool and take out to obtain Eu 2+ -doped fluorescent glass ceramics.

[0010] Preferably, in step S1, the mass ratio of the Eu 2+ -doped fluorescent powder to the glass powder is 1:(1 - 19);

[0011] Preferably, in step S1, the Eu 2+ -doped fluorescent powder is selected from at least one of BaMgAl 10 O 17 :Eu 2+ blue fluorescent powder, SrSi5AlO2N7:Eu 2+ cyan fluorescent powder, Ba 1.2 Sr 0.8 SiO4:Eu 2+ green fluorescent powder, Ba 0.5 Sr 1.5 SiO4:Eu 2+ yellow fluorescent powder, BaSr2SiO5:Eu 2+ orange fluorescent powder, SrAlSiN3:Eu 2+ red fluorescent powder, CaAlSiN3:Eu 2+ dark red fluorescent powder.

[0012] Preferably, in step S1, the glass powder is a low-melting-point glass powder, and the softening temperature of the glass powder is 400 - 500 °C;

[0013] More preferably, the glass powder is purchased from product Z5045 of Foshan Youhe Chemical Co., Ltd., and the nominal composition is P2O5 - Al2O3 - B2O3 - SiO2 - ZrO2 - CaO - SnO - Na2O - K2O.

[0014] Preferably, in step S1, the organic solvent is ethanol;

[0015] Preferably, in step S1, the total mass of the Eu 2+ -doped phosphor and the glass powder to the mass-volume ratio of the organic solvent is 1 g:(1 - 5) mL.

[0016] More preferably, the total mass of the Eu 2+ -doped phosphor and the glass powder to the mass-volume ratio of the organic solvent is 1 g:3 mL.

[0017] Preferably, in step S1, the drying temperature is 80 - 100 °C and the time is 60 - 300 min.

[0018] Preferably, in step S1, the sieving parameter is 200 - 500 mesh.

[0019] Preferably, in step S2, the parameters for dry pressing and shaping are uniaxial pressure of 5 - 10 MPa; the parameters for isostatic cold pressing are 50 - 200 MPa for 10 - 300 min.

[0020] Preferably, in step S2, the dry pressing and shaping are carried out in a prefabricated mold, and after demolding, cold isostatic pressing is carried out.

[0021] Preferably, in step S3, the volume ratio of hydrogen to nitrogen in the mixed atmosphere of hydrogen and nitrogen is 5 - 20:95 - 80.

[0022] Preferably, in step S3, the densification sintering is carried out on a joule heat sintering device placed in a closed box, and the heating source of the joule heat sintering device is provided by the joule heat converted from the energized carbon strip. Before sintering, the original air in the closed box is evacuated to a negative pressure of 0.01 Pa, and then a mixed atmosphere of hydrogen and nitrogen is filled and then energized for sintering.

[0023] Preferably, for the post-treatment of cutting and polishing: The Eu 2+ -doped fluorescent glass ceramic obtained in step S3 is cut to a suitable size according to the size design, and then polished to a smooth surface, and finally the Eu 2+ -doped fluorescent glass ceramic meeting the application requirements is obtained.

[0024] The present invention also provides a Eu 2+ -doped fluorescent glass ceramic prepared by the above preparation method.

[0025] The present invention also provides a near-ultraviolet laser-driven light-emitting device, including a heat dissipation substrate, a near-ultraviolet laser diode, and the above-mentioned Eu 2+ -doped fluorescent glass ceramic. The near-ultraviolet laser diode is installed on the heat dissipation substrate, and the Eu 2+ -doped fluorescent glass ceramic is installed 0 - 10 cm above the near-ultraviolet laser diode.

[0026] Compared with the prior art, the advantages of the present invention are as follows:

[0027] Eu of the present invention 2+ Preparation method of doped fluorescent glass ceramics, by adjusting the proportion of Eu 2+ doped phosphor, sintering time and protective atmosphere, to obtain Eu 2+ doped fluorescent glass ceramics with high luminous efficiency, and the synthesis time is significantly shortened, the process is simple, the cost is low, and it is easy to implement on a large scale.

[0028] The near-ultraviolet laser-driven light-emitting device of the present invention exhibits a high color rendering index and high brightness. Compared with the "blue laser + Y3Al5O 12 :Ce 3+ " light source in the prior art, there is no excessive laser blue hazard, and the missing blue light, red light and other bands in the white laser light source are supplemented to improve the color rendering performance of the white laser lighting light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 For the CaAlSiN3:Eu described in Examples 1-3 and Comparative Examples 1 and 2 2+ Glass ceramics and raw material CaAlSiN3:Eu 2+ Bar chart of quantum yield data of phosphor.

[0030] Figure 2 For the CaAlSiN3:Eu described in Examples 1, 4-7 2+ Fluorescence emission spectrum measured under the same conditions by the FLS1000 spectrometer for the glass ceramics.

[0031] Figure 3 For the Eu 2+ XRD phase diagram of doped glass ceramics and their corresponding commercial phosphor raw materials.

[0032] Figure 4 For the Eu 2+ Emission spectrum diagram of doped glass ceramics.

[0033] Figure 5a For the Eu 2+ Output spectrum diagram of the light source composed of doped multicolor glass ceramics configured on a near-ultraviolet laser.

[0034] Figure 5b For the Eu 2+ Change curve diagram of the output luminous flux of the light source composed of doped multicolor glass ceramics configured on a near-ultraviolet laser with the increase of laser input power. DETAILED DESCRIPTION OF THE INVENTION

[0035] In order to make the content of the present invention easier to be clearly understood, the following further describes the present invention in detail according to specific embodiments of the present invention in conjunction with the accompanying drawings.

[0036] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0037] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the description of the present invention, which are obvious to those skilled in the art. Other embodiments obtained from the description of the present invention are obvious to those skilled in the art. The description and embodiments of the present invention are merely exemplary.

[0038] The following describes the technical effects of the present invention in conjunction with specific embodiments.

[0039] The raw materials in the embodiments of the present invention are all purchased through commercial channels and used directly without any special treatment. Among them, the low-melting glass powder is the Z5045 product purchased from Foshan Youhe Chemical Co., Ltd. The nominal elemental composition of this product is P2O5 - Al2O3 - B2O3 - SiO2 - ZrO2 - CaO - SnO - Na2O - K2O; the softening temperature is 420 °C, the sintering temperature range is 420 - 650 °C, and the expansion coefficient range is 10 - 15×10 -6 .

[0040] The X-ray diffractometer adopted by the present invention is a PANalytical powder diffractometer.

[0041] The present invention uses an Edinburgh FLS1000 spectrometer to measure the fluorescence spectrum of the sample.

[0042] The present invention uses a Hamamatsu C13534 measuring instrument of Hamamatsu to measure the absolute quantum yield of photoluminescence of the example samples.

[0043] The field emission electron microscope adopted by the present invention is a Hitachi SU8220.

[0044] The present invention uses a self-built laser-coupled integrating sphere test system to measure parameters such as the spectrum, luminous flux, and color rendering index of a laser-driven light-emitting device. The test system consists of a customized integrating sphere with a diameter of 30 cm, an optical fiber spectrometer (Ocean Optics QE65 Pro), and a 405 nm laser (Ningbo Yuanming LSR405NL20W). The luminous signal is collected by the integrating sphere, transmitted through an optical fiber to the optical fiber spectrometer, and parameters such as the luminous flux and color rendering index are obtained using a standard lamp recognized by the National Institute of Metrology of China and NVLAP as a reference light source.

[0045] Example 1

[0046] Weigh CaAlSiN3:Eu 2+ phosphor (1 g) and low-melting-point glass powder raw material (2 g) in ethanol solvent (9 mL), mix them evenly, dry at 80 °C for 120 min to remove the ethanol solvent, and then sieve through a 300-mesh sieve to obtain a precursor mixture; then uniaxially press and shape it at a pressure of 5 MPa in a prefabricated mold, demold, and then perform cold isostatic pressing at 100 MPa for 30 min to obtain a CaAlSiN3:Eu 2+ glass-ceramic green body; subsequently, place the CaAlSiN3:Eu 2+ glass-ceramic green body on a Joule-heat sintering device, evacuate and purge with gas, then fill it with a 5% H2 - 95% N2 mixed gas, and then carry out densification sintering for 20 s under the conditions of a DC power supply of 60 V & 20 A, cool and take out; polish the sample to obtain a circular SrAlSiN3:Eu 2+ glass-ceramic sheet with a thickness of 1 mm and a diameter of 10 mm.

[0047] Example 2

[0048] The difference between Example 2 and Example 1 is that the protective gas filled after vacuum gas washing is different;

[0049] The protective gas filled in Example 2 is nitrogen.

[0050] Example 3

[0051] The difference between Example 3 and Example 1 is that the protective gas filled after vacuum gas washing is different;

[0052] The protective gas filled in Example 3 is argon.

[0053] Comparative Example 1

[0054] The difference between Comparative Example 1 and Example 1 is that the sintering method of CaAlSiN3:Eu 2+ glass-ceramic is different;

[0055] In Comparative Example 1, CaAlSiN3:Eu 2+The glass-ceramic green body was sintered in a muffle furnace at 470 °C for 30 min.

[0056] Comparative Example 2

[0057] The difference between Comparative Example 2 and Example 1 lies in the different sintering methods of CaAlSiN3:Eu 2+ for the glass-ceramics;

[0058] In Comparative Example 2, the CaAlSiN3:Eu 2+ glass-ceramic green body was placed in a tubular furnace and sintered at 470 °C for 30 min under a mixed gas condition of 5% H2 - 95% N2.

[0059] The photoluminescence quantum yields of the samples of Example 1, 2, 3 and Comparative Example 1, 2 were measured. As Figure 1 shown, the external quantum yields of Example 1, 2, 3 were all greater than 50%. The reason is that the sintering reaction was completed within 20 seconds, avoiding the migration of elements on the surface of the glass component and the phosphor crystal, which affected the crystallinity of the crystal. Comparative Example 1 and 2 are common sintering methods for fluorescent glass-ceramic materials. Due to the long sintering reaction time, there are migration conditions for the invasion of glass amorphous elements on the surface of the phosphor crystal. In Comparative Example 1 sintered in air, Eu 2+ will be oxidized to Eu 3+ , resulting in a low quantum yield. Although Comparative Example 2 uses a reducing atmosphere to prevent the oxidation of Eu 2+ , the glass contains components such as SiO2 and SnO, which are prone to form black or gray particles of Si and Sn elemental substances that absorb red light under a 5% H2 - 95% N2 reducing atmosphere, greatly reducing the quantum yield. Obviously, the luminescence efficiency of the samples of Example 1, 2, 3 sintered by Joule heat is better than that of the samples of Comparative Example 1, 2 sintered traditionally, indicating that the synthesis method of the Eu 2+ -doped fluorescent glass-ceramic by Joule heat rapid sintering of the present invention has more advantages. The degradation mechanism of CaAlSiN3:Eu 2+ is the fracture of several Ca / Al / Si-N chemical bonds by the erosion of foreign elements. N2 can slow down the fracture rate of this chemical bond. Therefore, the quantum yield of the sample of Example 2 is slightly better than that of Example 3. In addition, the main factors determining the photoluminescence quantum yield of the phosphor are the content of the activator Eu 2+ and its crystal local environment. CaAlSiN3:Eu 2+ Under high-temperature inert conditions, the surface-sensitive Eu 2+ will still be spontaneously oxidized to Eu 3+ . Adding a reducing H2 component can well limit the spontaneous oxidation of Eu 2+ . Therefore, the sample of Example 1 is significantly better than Example 2 and 3.

[0060] Example 4

[0061] Example 4 is different from Example 1 in that the mass ratio of the raw materials of CaAlSiN3:Eu 2+ phosphor to low-melting-point glass powder is different;

[0062] In Example 4, the mass ratio of CaAlSiN3:Eu 2+ phosphor to low-melting-point glass powder is 1:19.

[0063] Example 5

[0064] Example 5 is different from Example 1 in that the mass ratio of the raw materials of CaAlSiN3:Eu 2+ phosphor to low-melting-point glass powder is different;

[0065] In Example 5, the mass ratio of CaAlSiN3:Eu 2+ phosphor to low-melting-point glass powder is 1:9.

[0066] Example 6

[0067] Example 6 is different from Example 1 in that the mass ratio of the raw materials of CaAlSiN3:Eu 2+ phosphor to low-melting-point glass powder is different;

[0068] In Example 6, the mass ratio of CaAlSiN3:Eu 2+ phosphor to low-melting-point glass powder is 1:4.

[0069] Example 7

[0070] Example 7 is different from Example 1 in that the mass ratio of the raw materials of CaAlSiN3:Eu 2+ phosphor to low-melting-point glass powder is different;

[0071] In Example 7, the mass ratio of CaAlSiN3:Eu 2+ phosphor to low-melting-point glass powder is 1:1.

[0072] The fluorescence emission spectra of Examples 1, 4 - 7 measured under the same conditions of the FLS1000 spectrometer are as Figure 2 shown. As the mass ratio of the phosphor feed increases, the fluorescence emission intensity of the obtained fluorescent glass-ceramic material gradually increases. When the mass ratio of the CaAlSiN3:Eu 2+ phosphor to low-melting-point glass powder is 1:2, it reaches the highest, that is, the sample of Example 1 has the best feed ratio.

[0073] Example 8

[0074] Example 8 is different from Example 1 in that the phosphor fed is different;

[0075] The phosphor fed in Example 8 is SrAlSiN3:Eu 2+ Red phosphor

[0076] Example 9

[0077] The difference between Example 9 and Example 1 lies in the different phosphors fed;

[0078] The phosphor fed in Example 9 is BaSr2SiO5:Eu 2+ Orange phosphor

[0079] Example 10

[0080] The difference between Example 10 and Example 1 lies in the different phosphors fed;

[0081] The phosphor fed in Example 10 is Ba 0.5 Sr 1.5 SiO4:Eu 2+ Yellow phosphor

[0082] Example 11

[0083] The difference between Example 11 and Example 1 lies in the different phosphors fed;

[0084] The phosphor fed in Example 11 is Ba 0.5 Sr 1.5 SiO4:Eu 2+ Yellow phosphor

[0085] Example 12

[0086] The difference between Example 12 and Example 1 lies in the different phosphors fed;

[0087] The phosphor fed in Example 12 is SrSi5AlO2N7:Eu 2+ Cyan phosphor

[0088] Example 13

[0089] The difference between Example 13 and Example 1 lies in the different phosphors fed;

[0090] The phosphor fed in Example 13 is BaMgAl 10 O 17 :Eu 2+ Blue phosphor

[0091] The powder X-ray diffraction spectra of the samples in Examples 1, 8 - 13 are as Figure 3 shown, and the fluorescence emission spectra are as Figure 4As shown. The X-ray diffraction peaks of the prepared fluorescent glass-ceramic material are consistent with those of the raw fluorescent powder, indicating that during the entire synthesis process, the crystal properties of the fluorescent powder remain unchanged within the glass matrix, and no new secondary phase is formed due to erosion. It can be seen from the fluorescence spectrum that the prepared fluorescent glass-ceramic materials all emit the same light color as the corresponding original fluorescent powder. BaMgAl 10 O 17 :Eu 2+ (450nm), SrSi5AlO2N7:Eu 2+ (480nm), Ba 1.2 Sr 0.8 SiO4:Eu 2+ (530nm), Ba 0.5 Sr 1.5 SiO4:Eu 2+ (558nm), BaSr2SiO5:Eu 2+ (590nm), SrAlSiN3:Eu 2+ (620nm), CaAlSiN3:Eu 2+ (650nm). The emission spectrum corresponds to the 4f-5d transition radiation of Eu 2+ , covering from blue to deep red, and can form multicolor fluorescent glass-ceramics.

[0092] Example 14

[0093] The difference between Example 14 and Example 1 is that the fed fluorescent powder is different;

[0094] The fed fluorescent powder in Example 14 is a multicolor fluorescent powder with a mixing ratio of SrSi5AlO2N7:Eu 2+ :Ba 0.5 Sr 1.5 SiO4:Eu 2+ :CaAlSiN3:Eu 2+ = 3:3:5.

[0095] Figure 5a 、 Figure 5b The spectrum of the sample obtained in Example 14 installed in a light source assembled with a 405nm near-ultraviolet laser diode is shown. The luminous flux and color rendering index and other parameters are obtained using a standard lamp recognized by the National Institute of Metrology of China and NVLAP as a reference light source. Driven by a 20W near-ultraviolet laser, the assembled light source outputs 1042lm of white light. The spectrum of this white light continuously covers the visible light range, making its color rendering index as high as 94, far exceeding that of general laser white light illumination sources.

[0096] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included within the protection scope of the present invention.

Claims

1. A Eu 2+ -doped fluorescent glass-ceramic preparation method, characterized in that, It includes the following steps: S1. Mix the Eu 2+ -doped phosphor powder and glass powder evenly in an organic solvent, dry to remove the organic solvent, and screen to obtain a precursor mixture; S2. Dry-press and shape the precursor mixture obtained in step S1, and cold isostatically press to obtain a green body of the fluorescent glass-ceramics; S3. Under a mixed atmosphere of hydrogen and nitrogen, the green body of the fluorescent glass ceramic obtained in step S2 is subjected to densification sintering at 30 - 60 V and 15 - 30 A on a Joule heating sintering device for 5 - 60 s, and then cooled and taken out to obtain Eu 2+ -doped fluorescent glass ceramic.

2. The Eu according to claim 1 2+ A method for preparing doped fluorescent glass ceramics, characterized in that In step S1, the mass ratio of the Eu 2+ -doped phosphor to the glass powder is 1:(1 - 19); The Eu 2+ -doped phosphor is selected from BaMgAl 10 O 17 :Eu 2+ blue phosphor, SrSi5AlO2N7:Eu 2+ cyan phosphor, Ba 1.2 Sr 0.8 SiO4:Eu 2+ green phosphor, Ba 0.5 Sr 1.5 SiO4:Eu 2+ yellow phosphor, BaSr2SiO5:Eu 2+ orange phosphor, SrAlSiN3:Eu 2+ red phosphor, CaAlSiN3:Eu 2+ at least one of deep red phosphors.

3. According to claim 1, Eu 2+ A method for preparing doped fluorescent glass ceramics, characterized in that The softening temperature of the glass powder is 400-500 °C; The organic solvent is ethanol; The Eu 2+ The mass volume ratio of the total mass of the Eu-doped phosphor and the glass powder to the organic solvent is 1 g:(1-5) ml.

4. The Eu according to claim 3 2+ A method for preparing doped fluorescent glass ceramics, characterized in that The glass powder is P2O5-Al2O3-B2O3-SiO2-ZrO2-CaO-SnO-Na2O-K2O.

5. Eu according to claim 1 2+ The preparation method of doped fluorescent glass ceramics is characterized in that: In step S1, the drying temperature is 80-100 °C and the time is 60-300 min.

6. Eu according to claim 1 2+ The preparation method of doped fluorescent glass ceramics is characterized in that: In step S1, the sieving parameter is 200-500 mesh.

7. The preparation method of the Eu 2+ doped fluorescent glass-ceramics, characterized in that, In step S2, the dry-pressing and shaping parameter is a uniaxial pressure of 5-10 MPa; the isostatic pressing parameter is 50-200 MPa for 10-300 min.

8. The preparation method of the Eu 2+ doped fluorescent glass-ceramics according to claim 1, characterized in that, In step S3, the volume ratio of hydrogen to nitrogen in the mixed atmosphere of hydrogen and nitrogen is 5-20:95-80.

9. A Eu 2+ -doped fluorescent glass ceramic, characterized in that It is obtained by the preparation method according to any one of claims 1-8.

10. A near-ultraviolet laser-driven light-emitting device, characterized in that, Comprising a heat dissipation substrate, a near-ultraviolet laser diode, and the Eu-doped fluorescent glass-ceramic as described in claim 9, the near-ultraviolet laser diode is mounted on the heat dissipation substrate, and the Eu-doped fluorescent glass-ceramic is mounted 0-10 cm above the near-ultraviolet laser diode. 2+ The Eu-doped fluorescent glass-ceramic, the near-ultraviolet laser diode is mounted on the heat dissipation substrate, and the Eu 2+ -doped fluorescent glass-ceramic is mounted 0-10 cm above the near-ultraviolet laser diode.

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