Fluorescent glass ceramic, preparation method thereof and luminescent device

Abstract

The invention discloses fluorescent glass ceramic, a preparation method thereof and a luminescent device, and belongs to the technical field of luminescent materials. The fluorescent glass ceramic comprises glass powder and fluorescent powder, the glass powder comprises zinc borosilicate glass powder; the zinc borosilicate glass powder comprises the following components in percentage by mole: 5%-20% of SiO2, 10%-35% of B2O3, 20%-65% of ZnO, 0.3%-15% of P2O5, 2%-20% of RO and 0.1%-15% of R2O, RO is selected from at least one of MgO, CaO, SrO and BaO, and R2O is selected from at least one of Li2O, Na2O and K2O; the fluorescent powder comprises blue-green fluorescent powder; the emission peak wavelength of the blue-green fluorescent powder is 480-510 nm; based on the total mass of the glass powder and the fluorescent powder, the mass percentage content of the glass powder is 30-80%, and the mass percentage content of the fluorescent powder is 20-70%. The fluorescent glass ceramic is high in reliability and can be applied to high-power light emitting, a light emitting device formed by combining the fluorescent glass ceramic and a proper light source can provide an accurate azure light emitting effect, and the requirements in application scenes with harsh color requirements are met.

Description

Technical Field

[0001] This application relates to the field of luminescent materials technology, and in particular to a fluorescent glass ceramic, its preparation method, and a luminescent device. Background Technology

[0002] Existing azure LED (light-emitting diode) devices mostly use azure LED chips, but they suffer from problems such as low luminous efficiency and high cost. Although the organic encapsulation solution of LED chip + phosphor + glue has a significant cost advantage, the glue is prone to yellowing when the device temperature is high, which leads to accelerated light decay, difficulty in effective heat dissipation, and causes thermal quenching of phosphor and color coordinate drift. This results in poor reliability and low power consumption. Summary of the Invention

[0003] This application provides a fluorescent glass ceramic, its preparation method, and a light-emitting device. The fluorescent glass ceramic prepared in this application has high reliability and can be applied to high-power light emission. The light-emitting device combined with a specific light source can achieve a precise sky-blue light emission effect. Its color coordinates based on the CIE1931 chromaticity diagram are located within a specific quadrilateral area, making it very suitable for fields such as sky-blue indicator lights for automotive assisted driving and autonomous driving.

[0004] In a first aspect, embodiments of this application provide a fluorescent glass-ceramic, comprising glass powder and phosphor; the glass powder comprises zinc borosilicate glass powder; the zinc borosilicate glass powder comprises the following components in molar percentage: 5%~20% SiO2, 10%~35% B2O3, 20%~65% ZnO, 0.3%~15% P2O5, 2%~20% RO, and 0.1%~15% R2O, wherein RO is selected from at least one of MgO, CaO, SrO, and BaO, and R2O is selected from at least one of Li2O, Na2O, and K2O; the phosphor comprises a blue-green phosphor; the blue-green phosphor has an emission peak wavelength of 480~510 nm; based on the total mass of the glass powder and the phosphor, the mass percentage of the glass powder is 30%~80%, and the mass percentage of the phosphor is 20%~70%.

[0005] In the above technical solution, zinc borosilicate glass powder serves as the matrix. Its specific composition and ratio ensure that the glass has a low softening point and good chemical stability, enabling densification at a relatively low sintering temperature and preventing damage to the phosphor during co-firing. The blue-green phosphor allows it to be effectively excited by common blue or near-ultraviolet LED chips, emitting blue-green light. When mixed with the emitted light from the light source, it achieves sky-blue emission. By adjusting the ratio of glass powder to phosphor, co-firing ensures no damage and balances the mechanical strength, light transmittance, and fluorescence conversion efficiency of the fluorescent glass ceramic, resulting in both good reliability and efficient light conversion, achieving precise sky-blue emission.

[0006] In some embodiments, the blue-green phosphor comprises M a D b E c :xEu 2+ or BaSi2O2N2:Eu 2+ wherein: M comprises at least one of Sr, Ba, Ca, Mg, Zn; D comprises Al; E comprises O; 3.7≤a≤4.3, 12≤b≤16, 22≤c≤28, 0.01≤x≤0.5.

[0007] In the above technical solution, the blue-green phosphor has stable physical and chemical properties, and will not be damaged when co-fired with glass powder. The blue-green phosphor can be excited by light emitted by a light source and emit blue-green light. By controlling the component parameters, a blue-green light with high brightness, good color purity, excellent stability and better thermal quenching performance can be obtained. The light emitted by the light source can be mixed to accurately adjust the color coordinates of the light emitting device to the required area of the cyan color, and the cyan color light can be realized together.

[0008] In some embodiments, D further comprises at least one of B, Ga or In, and E further comprises at least one of F, Cl, Br or I.

[0009] In the above technical solution, by doping elements and adjusting the proportion, the spectral adjustable domain is further expanded, the environmental adaptability is improved, the interaction between the phosphor and the glass powder is weakened when co-fired with the glass powder, the efficiency loss is reduced, and the luminescent performance is better maintained. The long-term stability of the luminescence is improved while ensuring the accuracy of the spectrum.

[0010] In some embodiments, the blue-green phosphor comprises Sr 4-x Al 14 O 25 :xEu 2+ wherein, 0.02≤x≤0.3.

[0011] In the above technical solution, the phosphor has stable physical and chemical properties, and can maintain the integrity of its crystal structure and luminescent performance during sintering process, ensuring that the final phosphor glass ceramic has high light conversion efficiency and reliability. The blue-green phosphor can produce characteristic blue-green fluorescent emission after excitation, and the spectral energy distribution has a high overlap with the cyan color gamut. By mixing with the light emitted by the light source, the color coordinates of the entire device emission light can be accurately anchored in the cyan color standard area.

[0012] In some embodiments, the phosphor further comprises a green phosphor; the green phosphor satisfies at least one of the following conditions: (1) the emission peak wavelength of the green phosphor is 510-540 nm; (2) the green phosphor includes any one of β-Sialon:Eu 2+ , AlON:Mn 2+ , Lu3(Al,Ga)5O 12 :Ce 3+ or (Ba,Sr)2SiO4:Eu 2+ .

[0013] In the above technical solution, the green phosphor and the blue-green phosphor synergistically act, which can further finely control the overall emission spectrum of the fluorescent glass ceramic, so that the light-emitting color of the final device can be accurately designed to meet the specific needs in different application scenarios. The green phosphor has good thermal stability at a relatively low sintering temperature of the zinc-boron-silicate glass matrix, which can effectively reduce the thermal quenching and degradation of the phosphor during the sintering process. By adjusting the types and proportions of the blue-green phosphor and the green phosphor, accurate sky blue light emission can be achieved while maintaining the long-term reliability of the light-emitting device in a high-temperature and high-humidity environment.

[0014] In some embodiments, the surface of the phosphor is coated with a powder; the powder satisfies at least one of the following conditions: (1) the powder includes any one of aluminum oxide, silicon oxide, titanium dioxide, magnesium oxide, zinc oxide or boron nitride; (2) the particle size of the powder is 20-200 nm.

[0015] In the above technical solution, the nano-powder coating layer (thickness of 80-500 nm) has high chemical inertness and thermal stability, which can form a dense physical barrier on the surface of the phosphor particles, effectively blocking the ions (especially alkali metal ions) in the glass matrix from eroding the phosphor during low-temperature co-sintering with the glass powder, so that the phosphor can maintain high luminous efficiency and emission spectrum characteristics, and the thermal stability and service life of the fluorescent glass ceramic are improved.

[0016] In a second aspect, the embodiments of the present application provide a preparation method of a fluorescent glass ceramic, including the following steps: mixing and pressing glass powder and phosphor into a shape, and then sintering; based on the total mass of the glass powder and the phosphor, the mass percentage of the glass powder is 30%-80%, and the mass percentage of the phosphor is 20%-70%.

[0017] In the above technical solution, the glass powder fully melts and flows during sintering, forming a continuous, dense and highly transparent glass matrix that can effectively coat and protect the phosphor particles, ensuring uniform dispersion of the phosphor in the glass matrix, thereby obtaining a fluorescent glass ceramic with uniform light emission. The formed glass ceramic combines the density, chemical stability of glass and rigidity of ceramic, significantly improving the thermal stability, moisture resistance and mechanical strength.

[0018] In some embodiments, the sintering satisfies at least one of the following conditions: (1) the sintering temperature is 400-700 ℃; (2) the sintering time is 10 min-2 h; (3) the sintering pressure is 1-20 MPa.

[0019] In the above technical solution, the sintering temperature ensures that the glass powder can be fully softened and melted to obtain sufficient fluidity to wet the phosphor particles, fill the voids and form a dense continuous glass matrix, and minimize the damage of high-temperature thermal effects on the phosphor. The sintering time ensures that the above melting, flowing and preliminary densification processes can be completed, and reduces the significant thermal degradation of the phosphor due to long-term exposure to high temperature, resulting in a sharp decrease in luminous efficiency and thermal stability. In the preparation process, due to the larger volume ratio of the phosphor and the smaller volume ratio of the glass powder as the inorganic binder, the densification and strength of the phosphor glass ceramic can be improved by means of a certain pressure during the sintering process.

[0020] In a third aspect, the embodiments of the present application provide a light-emitting device, comprising a light source and the above-mentioned phosphor glass ceramic or the phosphor glass ceramic prepared by the above-mentioned preparation method, and the peak wavelength of the light source is 380-410 nm; or the peak wavelength of the light source is 430-460 nm.

[0021] In the above technical solution, the emission spectrum of the light source matches the excitation spectrum of the phosphor contained in the phosphor glass ceramic, which can be efficiently absorbed by the phosphor in the phosphor glass ceramic, thereby exciting the phosphor to emit light. The final emitted light of the light-emitting device is a mixture of the remaining excitation light that is not absorbed and the fluorescence emitted by the phosphor excited to emit light, which together realizes sky blue light emission.

[0022] In some embodiments, the emission light of the light-emitting device has color coordinates in the CIE1931 chromaticity diagram located in a quadrilateral region surrounded by points A (0.012, 0.495), B (0.200, 0.400), C (0.200, 0.320), and D (0.040, 0.320).

[0023] In the above technical solution, the color coordinates are limited within a specific quadrilateral region, which ensures that the light emitted by the light-emitting device is accurate sky blue. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0025] Figure 1 An optical microscope image of a fluorescent glass ceramic provided in Embodiment 6 of the present application; Figure 2 A coordinate position of a light emitting device provided in the present application in a CIE 1931 chromaticity diagram. DETAILED DESCRIPTION

[0026] In order to make the objects, technical solutions and advantages of the present application clearer, the following will further describe the present application in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0027] The current cerulean light LED device mostly uses cerulean light LED chips, but it has problems of low luminous efficiency and high cost. The organic packaging scheme of LED chip + fluorescent powder + glue has a great advantage in cost, but in a high temperature working environment, the glue is easy to yellow, which leads to accelerated light decay, and at the same time hinders effective heat dissipation, resulting in thermal quenching effect of the fluorescent powder and color coordinate shift, ultimately causing the reliability of the device to decrease and being difficult to operate stably at a higher power.

[0028] In order to solve the above technical problems, the present application provides a fluorescent glass ceramic, which comprises glass powder and fluorescent powder; the glass powder comprises zinc borosilicate glass powder; the zinc borosilicate glass powder comprises the following components in mole percentage: 5% to 20% of SiO2, 10% to 35% of B2O3, 20% to 65% of ZnO, 0.3% to 15% of P2O5, 2% to 20% of RO, and 0.1% to 15% of R2O, wherein RO is selected from at least one of MgO, CaO, SrO and BaO, and R2O is selected from at least one of Li2O, Na2O and K2O; the fluorescent powder comprises blue-green fluorescent powder; the blue-green fluorescent powder has an emission peak wavelength of 480 to 510 nm; based on the total mass of the glass powder and the fluorescent powder, the mass percentage of the glass powder is 30% to 80%, and the mass percentage of the fluorescent powder is 20% to 70%. By accurately controlling the mass ratio of the glass matrix and the fluorescent powder, the fluorescent powder will not be damaged during co-firing, and the prepared fluorescent glass ceramic has good mechanical strength, optical transmittance and fluorescent conversion efficiency, and can realize efficient light conversion and precise cerulean light emission after being matched with a suitable light source.

[0029] In some embodiments of the present application, the blue-green phosphor comprises M a D b E c :xEu 2+ or BaSi2O2N2:Eu 2+ wherein: M comprises at least one of Sr, Ba, Ca, Mg, Zn; D comprises Al; E comprises O; 3.7≤a≤4.3, 12≤b≤16, 22≤c≤28, 0.01≤x≤0.5. Specifically, x can be 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5 or a value within a range between any two of them. As an example, the blue-green phosphor comprises Sr 4- x Al 14 O 25 :xEu 2+ wherein 0.02≤x≤0.3. For example, x can be 0.02, 0.04, 0.06, 0.08, 0.1, 0.14, 0.18, 0.22, 0.26, 0.3 or a value within a range between any two of them. When x satisfies the above range, the blue-green phosphor exhibits excellent long-term stability, with both light decay rate and color coordinate drift significantly reduced, ensuring the final fluorescent glass ceramic has high light conversion efficiency and reliability.

[0030] In some embodiments of the present application, D further comprises at least one of B, Ga or In, and E further comprises at least one of F, Cl, Br or I. By doping elements and adjusting the proportion, the spectral tunable domain can be further expanded, the environmental adaptability can be improved, the decrease of the luminous efficiency of the phosphor caused by sintering process can be reduced, the long-term stability of the luminescence can be improved while ensuring the accuracy of the spectrum.

[0031] In some embodiments of the present application, the phosphor further comprises a green phosphor; the green phosphor comprises β-Sialon:Eu 2+ , AlON:Mn 2+ , Lu3(Al,Ga)5O 12 :Ce 3+ or (Ba,Sr)2SiO4:Eu 2+Any one of the above; the emission peak wavelength of the green phosphor is 510-540 nm, for example, it can be 510 nm, 515 nm, 520 nm, 525 nm, 530 nm, 535 nm, 540 nm or a value within a range consisting of any two of them. When the emission peak wavelength of the green phosphor meets the above range, the emission spectrum can be well matched with the emission spectrum of the light source and the emission spectrum of the blue-green phosphor, and the color coordinates of the final sky blue light emission can more accurately fall into the target area.

[0032] In some embodiments of the present application, the mass percentage of the glass powder is 30%-80% and the mass percentage of the blue-green phosphor is 20%-70% based on the total mass of the glass powder and the phosphor.

[0033] In some embodiments of the present application, the mass percentage of the glass powder is 30%-80%, the mass percentage of the blue-green phosphor is 10%-40% and the mass percentage of the green phosphor is 10%-30% based on the total mass of the glass powder and the phosphor.

[0034] Of course, in some embodiments of the present application, in order to avoid the phosphor being eroded and contaminated by ions in the glass matrix (especially alkali metal ions) during low-temperature co-sintering with the glass powder, a nano powder will also be coated on the surface of the phosphor; the powder includes any one of alumina, silica, titanium dioxide, magnesium oxide, zinc oxide or boron nitride. The particle size of the powder is 20-200 nm, for example, it can be 20 nm, 40 nm, 60 nm, 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm, 200 nm or a value within a range consisting of any two of them.

[0035] In some embodiments of the present application, the preparation method of the fluorescent glass ceramic includes the following steps: mixing the glass powder and the phosphor and pressing into a shape, and then sintering; the mass percentage of the glass powder is 30%-80% and the mass percentage of the phosphor is 20%-70% based on the total mass of the glass powder and the phosphor. The prepared glass ceramic combines the density and chemical stability of glass with the rigidity of ceramic, significantly improving the thermal stability, moisture resistance and mechanical strength.

[0036] Specifically, in this step, the sintering temperature is 400-700 ℃, for example, it can be 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃ or a value within a range consisting of any two of them. When the sintering temperature meets the above range, the glass powder can be melted and flowed to effectively coat the phosphor particles, while reducing the degradation of the phosphor.

[0037] In some embodiments of the present application, the sintering time is 10 min to 2 h, for example, it can be 10 min, 0.5 h, 1 h, 1.5 h, 2 h or a value within a range consisting of any two of them. When the sintering time meets the above range, the glass powder can be fully melted and flowed to form a dense and non-porous continuous matrix, and the physical and chemical wetting with the fluorescent powder particles to form a firmly bonded interface.

[0038] In addition, in some embodiments of the present application, the light emitting spectrum of the cyan light emitting device is close to the monochromatic spectrum, and the amount of fluorescent powder used in the preparation process accounts for a large proportion. Due to the large volume ratio of the fluorescent powder, the volume ratio of the glass powder acting as an inorganic binder is small. In order to ensure the density and strength of the final fluorescent glass, a certain pressure is used in the sintering process to greatly improve the density and strength of the fluorescent glass. The sintering pressure is 1-20 MPa, for example, it can be 1 MPa, 2 MPa, 4 MPa, 6 MPa, 8 MPa, 10 MPa, 12 MPa, 14 MPa, 16 MPa, 18 MPa, 20 MPa or a value within a range consisting of any two of them.

[0039] In some embodiments of the present application, the light emitting device includes a light source and the above-mentioned fluorescent glass ceramic. The emission peak wavelength of the light source is 380-410 nm, for example, it can be 380 nm, 382 nm, 385 nm, 390 nm, 395 nm, 400 nm, 405 nm, 410 nm or a value within a range consisting of any two of them. When the emission peak wavelength of the light source meets the above range, it can be efficiently absorbed by the fluorescent powder and converted into cyan fluorescent light with extremely high purity. The emission light of the light source is in the ultraviolet region which is not sensitive to the human eye, and does not participate in the final light color synthesis, ensuring that the emitted light is accurate cyan light.

[0040] In some embodiments of the present application, the light emitting device includes a light source and the above-mentioned fluorescent glass ceramic. The emission peak wavelength of the light source is 430-460 nm, for example, it can be 430 nm, 435 nm, 440 nm, 445 nm, 450 nm, 455 nm, 460 nm or a value within a range consisting of any two of them. When the emission peak wavelength of the light source meets the above range, the fluorescent powder can be efficiently excited to emit light. The partially transmitted blue light and the light emitted by the fluorescent powder are mixed together to show cyan color, which helps to improve the light color stability and long-term service life of the light emitting device.

[0041] In some embodiments of the present application, the color coordinates of the emitted light of the light emitting device are located in the quadrilateral region surrounded by points A (0.012, 0.495), B (0.200, 0.400), C (0.200, 0.320) and D (0.040, 0.320) in the CIE1931 chromaticity diagram, as shown inFigure 2 The luminescent color represented in this quadrilateral region is the sky blue color described in the present application.

[0042] The following terms are explained as follows in the present application: Emission peak wavelength: refers to the wavelength corresponding to the maximum intensity of the emitted light spectrum of a luminescent material such as a phosphor, quantum dots, a semiconductor itself, or a luminescent device. It represents the main luminescent color of the material or device.

[0043] CIE 1931 Chromaticity Diagram is a standard colorimetric system developed by the International Commission on Illumination (CIE) in 1931 for quantitatively describing colors. It is a fundamental tool for representing colors in the fields of color science and industry. The CIE 1931 Chromaticity Diagram achieves precise definition and visual representation of colors by converting the human eye's perception of different wavelengths of light into mathematical coordinates.

[0044] The present application is further described in detail below in conjunction with examples. Unless otherwise specified, the raw materials used in the following examples are all from ordinary commercially available products, and the devices or equipment used are all purchased from conventional market channels. In the specific examples of the present application, the light source is an LED chip, and the LED device holder is 2016.

[0045] An optical microscope of M330-M100 type from OSA Microscopes was used to observe the light source as coaxial light, and the microstructure pictures of the fluorescent glass ceramic sheet were observed and photographed. As shown in Figure 1 , the optical microstructure picture of the fluorescent glass ceramic of Example 6 of the present application is shown, wherein the continuous matrix is glass, and the spherical particles are Lu3(Al,Ga)5O 12 :Ce 3+ Green fluorescent powder, rod-shaped particles are BaSi2O2N2:Eu 2+ Blue-green fluorescent powder.

[0046] A HASS2000 type LED photoelectric test system from YUANFANG Optoelectronics was used to test the emission spectrum of the luminescent device, and the color coordinates of the luminescent device were obtained through the software, and the color coordinate position was marked on the CIE 1931 Chromaticity Diagram.

[0047] Example 1 Fluorescent glass ceramic, comprising a glass powder and a fluorescent powder; The zinc borosilicate glass powder comprises the following components in mole percentage: 10% SiO2, 25% B2O3, 45% ZnO, 10% P2O5, 5% MgO, 5% Li2O; The fluorescent powder is Sr4Al 14 O 25 :Eu 2+, the emission peak wavelength is 490 nm, the surface of the fluorescent powder is coated with alumina powder, the particle size of the powder is 100 nm, and the thickness of the coating layer formed by the powder is about 300 nm; Based on the total mass of the glass powder and the fluorescent powder, the mass percentage of the glass powder is 40%, and the mass percentage of the fluorescent powder is 60%.

[0048] The fluorescent glass ceramic preparation method is as follows: the glass powder and the fluorescent powder are mixed and pressed into a shape, and then sintered, the sintering temperature is 500 DEG C, the sintering time is 1 h, and the sintering pressure is 2 MPa.

[0049] The sintered fluorescent glass ceramic ingot is subjected to slicing, grinding and polishing treatment to obtain a fluorescent glass ceramic substrate with a thickness of 0.15 mm, and then the fluorescent glass ceramic substrate is cut to obtain a fluorescent glass ceramic sheet with a length x width of 1 mm x 1 mm, and then the fluorescent glass ceramic sheet is attached to the light emitting surface of the LED chip to obtain an LED lamp emitting sky blue light, wherein the emission peak wavelength of the LED chip is 450 nm.

[0050] Example 2 The difference from example 1 is that the zinc borosilicate glass powder comprises the following components with a molar percentage of 10% SiO2, 25% B2O3, 45% ZnO, 10% P2O5, 5% CaO, 5% Na2O.

[0051] Example 3 The difference from example 1 is that the zinc borosilicate glass powder comprises the following components with a molar percentage of 15% SiO2, 20% B2O3, 33% ZnO, 12% P2O5, 10% CaO, 10% Na2O.

[0052] Example 4 The difference from example 1 is that the zinc borosilicate glass powder comprises the following components with a molar percentage of 15% SiO2, 20% B2O3, 33% ZnO, 12% P2O5, 10% MgO, 10% Li2O.

[0053] Example 5 The difference from example 1 is that based on the total mass of the glass powder and the fluorescent powder, the mass percentage of the glass powder is 50%; the fluorescent powder is Sr4Al 14 O 25 :Eu 2+ and β-Sialon:Eu 2+ , wherein the emission peak wavelength of Sr4Al 14 O 25 :Eu 2+ is 490 nm, and the mass percentage is 40%; the emission peak wavelength of β-Sialon:Eu2+ The emission peak wavelength is 530 nm, and the mass percentage is 10%.

[0054] Example 6 The difference from Example 1 is that, based on the total mass of glass powder and phosphor, the mass percentage of glass powder is 50%; the phosphor is BaSi2O2N2:Eu. 2+ and Lu3(Al,Ga)5O 12 :Ce 3+ Among them, BaSi2O2N2:Eu 2+ The emission peak wavelength is 485 nm, and the mass percentage content is 30%; Lu3(Al,Ga)5O 12 :Ce 3+ The emission peak wavelength is 525 nm, and the mass percentage is 20%.

[0055] Example 7 The difference from Example 1 is that, based on the total mass of glass powder and phosphor, the mass percentage of glass powder is 30% and the mass percentage of phosphor is 70%.

[0056] Example 8 The difference from Example 1 is that, based on the total mass of glass powder and phosphor, the mass percentage of glass powder is 80% and the mass percentage of phosphor is 20%.

[0057] Example 9 The difference from Example 1 is that the phosphor surface is coated with alumina powder with a particle size of 20 nm and the coating layer formed by the powder is about 100 nm thick.

[0058] Example 10 The difference from Example 1 is that the phosphor surface is coated with alumina powder with a particle size of 200 nm and the coating layer formed by the powder is about 400 nm thick.

[0059] Example 11 The difference from Example 1 is that the phosphor surface is coated with boron nitride powder with a particle size of 20 nm and the coating layer formed by the powder is about 80 nm thick.

[0060] Example 12 The difference from Example 1 is that the phosphor surface is coated with boron nitride powder with a particle size of 200 nm and the coating layer formed by the powder is about 500 nm thick.

[0061] Example 13 The difference from Example 1 is that, in the fluorescent glass preparation method, the sintering temperature is 700 ℃, the sintering time is 10 min, and the sintering pressure is 1 MPa.

[0062] Example 14 The difference from Example 1 is that, in the fluorescent glass preparation method, the sintering temperature is 400 ℃, the sintering time is 2 h, and the sintering pressure is 20 MPa.

[0063] Example 15 The difference from Example 1 is that the LED chip has an emission peak wavelength of 380 nm.

[0064] Example 16 The difference from Example 1 is that the LED chip has an emission peak wavelength of 410 nm.

[0065] Example 17 The difference from Example 1 is that the LED chip has an emission peak wavelength of 430 nm.

[0066] Example 18 The difference from Example 1 is that the LED chip has an emission peak wavelength of 460 nm.

[0067] Comparative Example 1 There is no fluorescent glass ceramic, only an LED chip with an emission peak wavelength of 495 nm, the LED device support is 2016, and the packaging glue is selected to be silicone.

[0068] Comparative Example 2 Fluorescent powder: BaSi2O2N2:Eu with an emission peak wavelength of 485 nm 2+ and Lu3(Al, Ga)5O 12 : Ce with an emission peak wavelength of 525 nm 3+ .

[0069] LED chip: with an emission peak wavelength of 450 nm.

[0070] The fluorescent powder and the LED chip are combined to form a light-emitting device, the LED device support is 2016, and the packaging glue is selected to be silicone.

[0071] Comparative Example 3 The difference from Example 1 is that, based on the total mass of the glass powder and the fluorescent powder, the mass percentage content of the glass powder is 20%, and the mass percentage content of the fluorescent powder is 80%.

[0072] Comparative Example 4 The difference from Example 1 is that, based on the total mass of the glass powder and the fluorescent powder, the mass percentage content of the glass powder is 90%, and the mass percentage content of the fluorescent powder is 10%.

[0073] Test method The light emitting devices of Examples 1-18 and Comparative Examples 1-4 were tested for color coordinates, luminous flux, light decay and color drift Dxy under 1000 hours of light at 85 ℃, 85% humidity, and current / voltage of 500 mA / 3 V.

[0074] The test results of Examples 1-18 and Comparative Examples 1-4 can be seen in Table 1.

[0075] Table 1 Test results of various examples and comparative examples

[0076] From the comparison of Examples 1-18 and Comparative Examples 1-2, it can be seen that although the color coordinates of the light emitting devices of Examples 1-18 and Comparative Examples 1-2 based on the CIE1931 chromaticity diagram are within a certain quadrilateral region, they can emit cyan light, but the luminous flux, light decay and color drift of Examples 1-18 are all better than those of Comparative Examples 1-2. This shows that the fluorescent glass ceramic of the present application more effectively absorbs the light emitted by the LED chip, has higher light conversion efficiency, less light loss, especially the mixed phosphor scheme of Examples 5 and 6, the luminous flux is further improved, which is obviously better than the silicone encapsulation scheme of Comparative Example 2. In a high temperature and high humidity (85 ℃, 85% humidity) environment, the fluorescent glass ceramic as an encapsulation material has better thermal stability and humidity resistance, its dense inorganic structure can effectively block water vapor and oxygen, protect the phosphor from erosion, thereby greatly improving the service life and reliability of the light emitting device. In addition, the color of the fluorescent glass ceramic device of the present application is very stable during long-term aging, which benefits from the fact that the phosphor is firmly sintered in the stable glass matrix, avoiding the problems of color drift caused by aging of organic silicone or separation of phosphor and encapsulation material.

[0077] From the comparison of Examples 1, 7, 8 and Comparative Examples 3-4, it can be seen that the color coordinates of the light emitting devices of Examples 1, 7, 8 based on the CIE1931 chromaticity diagram are within a certain quadrilateral region, they can emit cyan light, and all show good performance, but the color coordinates of the light emitting devices of Comparative Examples 3-4 based on the CIE1931 chromaticity diagram are not within a certain quadrilateral region, they cannot emit accurate cyan light. At the same time, the mass ratio of glass powder to phosphor is the key to ensure the comprehensive performance of the light emitting device, the glass powder content of Comparative Example 3 is too low, the glass matrix cannot completely wrap the phosphor, leading to a decrease in protection, and an increase in light decay and color drift. The glass powder content of Comparative Example 4 is too high, and the phosphor content is too low, resulting in a significant decrease in luminous flux.

[0078] Through comparison of the above examples and comparative examples, it can be obviously seen that the luminescent device composed of the fluorescent glass ceramic of the application and a specific light source can provide accurate sky blue light emitting effect, and has obvious advantages in light emitting efficiency and long-term light decay performance. By optimizing the ratio of glass powder and fluorescent powder, using mixed fluorescent powder and other technical solutions, the light efficiency, reliability and color stability of the luminescent device can be further improved.

[0079] The above only describes the preferred embodiments of the application and is not intended to limit the application. Any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A fluorescent glass-ceramic, characterized in that, Including glass powder and phosphor; The glass powder includes zinc borosilicate glass powder; the zinc borosilicate glass powder comprises the following components in molar percentage: 5%~20%SiO2, 10%~35%B2O3, 20%~65%ZnO, 0.3%~15%P2O5, 2%~20%RO, 0.1%~15%R2O, wherein RO is selected from at least one of MgO, CaO, SrO, and BaO, and R2O is selected from at least one of Li2O, Na2O, and K2O; The phosphor includes a blue-green phosphor; the emission peak wavelength of the blue-green phosphor is 480~510 nm. Based on the total mass of the glass powder and the phosphor, the mass percentage of the glass powder is 30% to 80%, and the mass percentage of the phosphor is 20% to 70%.

2. The fluorescent glass-ceramic according to claim 1, characterized in that, The blue-green phosphor includes M a D b E c :xEu 2+ or BaSi2O2N2:Eu 2+ One of them, Wherein: M includes at least one of Sr, Ba, Ca, Mg, and Zn; D includes Al; E includes O; 3.7≤a≤4.3, 12≤b≤16, 22≤c≤28, 0.01≤x≤0.

5.

3. The fluorescent glass-ceramic according to claim 2, characterized in that, D also includes at least one of B, Ga, or In, and E also includes at least one of F, Cl, Br, or I.

4. The fluorescent glass-ceramic according to claim 2, characterized in that, The blue-green phosphor includes Sr 4- x Al 14 O 25 :xEu 2+ , where 0.02≤x≤0.

3.

5. The fluorescent glass-ceramic according to any one of claims 1 to 4, characterized in that, The phosphor further includes a green phosphor; the green phosphor satisfies at least one of the following conditions: (1) The emission peak wavelength of the green phosphor is 510~540 nm; (2) The green phosphor includes β-Sialon:Eu 2+ AlON:Mn 2+ Lu3(Al,Ga)5O 12 :Ce 3+ Or (Ba,Sr)2SiO4:Eu 2+ Any one of them.

6. The fluorescent glass-ceramic according to claim 1, characterized in that, The phosphor is coated with powder; the powder satisfies at least one of the following conditions: (1) The powder includes any one of aluminum oxide, silicon oxide, titanium dioxide, magnesium oxide, zinc oxide or boron nitride; (2) The particle size of the powder is 20~200 nm.

7. A method for preparing fluorescent glass-ceramics, characterized in that, The process includes the following steps: mixing glass powder and phosphor powder and pressing them into shape, and then sintering them; based on the total mass of the glass powder and the phosphor powder, the mass percentage of the glass powder is 30% to 80%, and the mass percentage of the phosphor powder is 20% to 70%.

8. The method for preparing fluorescent glass-ceramics according to claim 7, characterized in that, The sintering satisfies at least one of the following conditions: (1) The sintering temperature is 400~700 ℃; (2) The sintering time is 10 min to 2 h; (3) The sintering pressure is 1~20 MPa.

9. A light-emitting device, characterized in that, The light source includes a fluorescent glass ceramic prepared by the method of any one of claims 1 to 6 or any one of claims 7 to 8, wherein the emission peak wavelength of the light source is 380 to 410 nm; or the emission peak wavelength of the light source is 430 to 460 nm.

10. The light-emitting device according to claim 9, characterized in that, The color coordinates of the emitted light from the light-emitting device in the CIE1931 chromaticity diagram are located within the quadrilateral area enclosed by points A (0.012, 0.495), B (0.200, 0.400), C (0.200, 0.320), and D (0.040, 0.320).

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