Narrow-band emission fluorescent powder-glass composite material for laser fluorescent display as well as preparation method and application thereof

Abstract

The invention discloses a narrow-band emission fluorescent powder-glass composite material for laser fluorescent display as well as a preparation method and application of the narrow-band emission fluorescent powder-glass composite material. The problems of heat accumulation and efficiency attenuation of traditional fluorescent powder under high-power laser irradiation are solved through a rapid compounding process of an ultralow-melting-point glass matrix (SnF2-NaF-P2O5 system) and narrow-band fluorescent powder (such as KSF: Mn and beta-SiAlON: Eu) in cooperation with a dynamic heat dissipation design of a device. Stable light output is achieved under the 50W laser power, the luminous flux reaches 684lm and 4770lm respectively, and the color gamut covers 125% Rec.709 after the blue laser is coupled with blue laser. Meanwhile, the device is suitable for various commercial fluorescent powder and supports the design of a patterned fluorescent rotating wheel. The application bottleneck of traditional fluorescent powder is broken through, and the fluorescent powder is particularly suitable for high-end display scenes such as IMAX cinema, AR / VR immersive display and high-brightness engineering projection.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, specifically relating to a narrowband emitting phosphor-glass composite material for laser fluorescent displays and its preparation method, and also to a complete laser fluorescent display system formed by combining the phosphor-glass composite material with a 455nm blue laser and a beam splitter. Background Technology

[0002] With the rapid development of display technology in the field of immersive visual experiences, Laser Phosphor Display (LPD) has gradually become the mainstream technology for cinema-grade projection, AR / VR, and high-brightness engineering displays due to its unique advantages such as high brightness, wide color gamut, and no speckle. However, the further development of laser display still faces two major challenges: the thermal management problem under high-power lasers and the efficient integration problem of narrowband phosphors.

[0003] In high-power laser environments, traditional phosphor materials (such as YAG:Ce) 3+ Light conversion is achieved through encapsulation with organic resin, but this is problematic when the laser power density exceeds 6W / mm². 2 At this point, the quantum efficiency drops by more than 40%, accompanied by structural failure. This thermal accumulation effect directly limits the stability and lifetime of the system. Although single-crystal and fluorescent ceramic materials have high thermal conductivity (>5 W·m), -1 ·K -1 However, their complex fabrication process and high cost limit their commercial application. Furthermore, these materials are difficult to integrate with narrowband phosphors (such as β-SiAlON:Eu). 2+ K2SiF6:Mn 4+ The chemical sensitivity of the substance further exacerbates the challenges of thermal management.

[0004] Traditional phosphors suffer from luminous efficacy decay due to heat accumulation under high-power lasers, making it difficult for the system to maintain high brightness output. Dynamic thermal management technologies (such as high-speed phosphor wheel rotation) alleviate the heat accumulation problem to some extent, basically meeting the requirements of high-end display scenarios (such as IMAX cinemas and AR / VR) for high brightness and stability.

[0005] Narrowband phosphors (such as K2SiF6:Mn) 4+ and β-SiAlON:Eu 2+ Phosphors, due to their excellent color purity and thermal stability, have become key materials for achieving ultra-wide color gamuts in laser displays. However, existing glass matrices are prone to oxidation and decomposition of phosphors during high-temperature sintering (>600℃), leading to a significant loss in quantum efficiency (<80%). For example, K2SiF6:Mn 4+ It is easily decomposed at high temperatures, β-SiAlON:Eu 2+Interfacial reactions lead to a decrease in luminescence performance. In addition, the existing glass matrix has poor versatility and is difficult to be compatible with various commercial phosphors (such as nitrides and fluorides), which limits the integration efficiency of multicolor light conversion systems.

[0006] In recent years, researchers have attempted to address these issues through rapid synthesis techniques (such as particle self-stabilization methods). (Sun Y, Wang Y, Chen W, et al. Rapid synthesis of phosphor-glass composites in seconds based on particle self-stabilization[J]. Nature Communications, 2024, 15(1): 1033.)(Zhang D, Xiao W, Liu C, et al. Highly efficient phosphor-glass composites by pressureless sintering[J]. Nature Communications, 2020, 11(11): 2805.) However, these methods have limited compatibility with commercially available phosphors that are unstable on the surface, and the quantum efficiency still needs optimization. For example, it is difficult to achieve uniform dispersion of phosphors in existing glass matrices during rapid synthesis, resulting in poor light output efficiency and color gamut performance. In addition, the lack of universality of existing materials makes it difficult to support the flexible design of multicolor light conversion systems, further limiting the commercialization of laser display technology.

[0007] In the field of laser phosphor displays, the bottlenecks of existing technologies mainly lie in thermal management under high-power lasers, efficient integration of narrowband phosphors, and the limitations of dynamic thermal management. These problems directly limit the brightness, color gamut, and stability of the system, becoming key obstacles to the development of laser display technology. Therefore, developing a phosphor-glass composite material that combines high thermal stability, high quantum efficiency, and excellent versatility is crucial to propelling laser display technology towards higher performance and wider applications. Summary of the Invention

[0008] This invention addresses the challenges of fabricating bulk narrowband phosphor materials, insufficient thermal stability, and poor versatility in existing Laser Phosphor Display (LPD) technology. Considering the needs of the LPD field for high-brightness, high-color-gamut, and laser-irradiation-resistant luminescent materials, this invention proposes a narrowband emitting phosphor-glass composite material for laser displays, along with its preparation method and applications. This material combines an ultra-low melting point glass matrix (SnF2-NaF-P2O5 system) with commercially available narrowband phosphors (such as K2SiF6:Mn). 4+ and β-SiAlON:Eu2+ The rapid composite process solves the problems of heat accumulation and efficiency decay of traditional phosphors in high-power laser environments. In laser phosphor display applications, this material exhibits high power laser compatibility, achieving stable light output at 50W laser power without laser saturation; it achieves 125% of the Rec.709 color gamut standard; it is suitable for various commercial phosphors, supports patterned phosphor wheel designs, and provides a flexible optical solution for laser phosphor display systems.

[0009] The technical solution of this invention is:

[0010] In a first aspect, the present invention provides a narrowband phosphor-glass composite material, the components of which include an ultra-low melting point fluoride glass matrix and a narrowband phosphor, wherein the phosphor is dispersed in the ultra-low melting point glass matrix.

[0011] The glass matrix is ​​based on the SnF2-NaF-P2O5 system, and its components include 55-60 mol% stannous fluoride, 5-10 mol% sodium fluoride, and 30-40 mol% phosphorus pentoxide. It has a low melting point of 280-350℃ and exhibits low viscosity, high wettability, high thermal conductivity (0.7 W / m·K), and excellent chemical stability.

[0012] The narrowband phosphor is a commercially available narrowband phosphor, including BaMgAl. 10 O 17 Eu 2+ Lu3Al5O 12 :Ce 3+ Y3Al5O 12 :Ce 3+ BaSrSiO4:Eu 2+ BaSr2SiO5:Eu 2+ SrAlSiN3:Eu 2+ K2SiF6:Mn 4+ β-SiAlON:Eu 2+ At least one of them.

[0013] This glass matrix can be rapidly composited with narrowband phosphors, avoiding the oxidation and decomposition of phosphors during high-temperature sintering, and ensuring a quantum efficiency of 94.6% (K2SiF6:Mn). 4+ ) and 87.8% (β-SiAlON:Eu 2+ ).

[0014] Secondly, the present invention provides a method for preparing the above-mentioned narrowband emitting phosphor-glass composite material, comprising the following steps:

[0015] (1) Mix SnF2, NaF and NH4H2PO4 in a molar ratio of (55-60):(5-10):(60-80) to form glass powder, grind it, and melt it at 280-350℃ for 15-20 minutes to obtain glass melt;

[0016] (2) Add the narrow-band phosphor to the glass melt, wherein the mass ratio of glass powder to narrow-band phosphor is (96-99.5):(0.5-4), mix, and stir at a speed of 1-5 rpm for 5-10 seconds to achieve uniform dispersion;

[0017] (3) The mixture is quickly poured into a mold and quenched in air to obtain the narrow-band emitting phosphor-glass composite material.

[0018] This invention achieves uniform dispersion of narrowband phosphors in a glass matrix through a rapid composite process (completed within 10 seconds). This process is not only energy-efficient and highly effective, but also applicable to a variety of commercial phosphors (such as nitrides and fluorides), demonstrating excellent versatility.

[0019] Thirdly, this invention provides the application of the aforementioned narrow-band emitting phosphor-glass composite material in the preparation of a laser phosphor rotor. The narrow-band emitting phosphor-glass composite material is processed into a disc, a small hole is drilled in the center of the disc, and it is fixed to a rotor support via a motor shaft. Ultraviolet-cured adhesive is then used to bond the glass-phosphor composite material to the metal rotor.

[0020] Through high-speed rotation (≥7200rpm), the phosphor wheel achieves dynamic thermal management, effectively mitigating heat accumulation issues. At 50W laser power, the red light flux reaches 684lm, and the green light flux reaches 4770lm, covering 125% of the Rec.709 color gamut standard, significantly superior to traditional YAG:Ce-based laser sources (103%). The patterned design of the phosphor wheel supports multi-color light mixing, providing a flexible optical solution for laser display systems.

[0021] Fourthly, this invention provides the application of the aforementioned narrowband emitting phosphor-glass composite material in the integration of a laser phosphor display system. The narrowband emitting phosphor-glass composite material is combined with a 455nm blue laser and a beam splitter to form a complete laser display system. A patterned phosphor wheel enables the mixing of red and green light and partial reflection of blue light, outputting high-throughput white light without speckle. This system is suitable for high-end display scenarios such as IMAX cinemas, AR / VR immersive displays, and high-brightness engineering projections, significantly improving display effects and user experience.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. Ultra-low melting point processing to avoid thermal damage to phosphors.

[0024] Traditional glass matrices (such as silicates and phosphates) have high melting points (>600℃), and high-temperature sintering can easily lead to narrow-band phosphors (such as β-SiAlON:Eu) sintering. 2+ KSF:Mn 4+ This invention utilizes a SnF2-NaF-P2O5 glass system, which has a low melting point of 280–350°C and low melt viscosity, enabling rapid coating of phosphors at low temperatures, avoiding thermal damage, and maintaining the chemical stability of the phosphors.

[0025] 2. Universal compatibility with multiple phosphors, overcoming material limitations.

[0026] Currently, single-crystal and ceramic phosphors are only compatible with specific phosphors (such as YAG:Ce). 3+ Furthermore, it is incompatible with sensitive materials such as nitrides and fluorides. This invention utilizes the self-stabilizing properties of the glass matrix interface to support BaMgAl... 10 O 17 Eu 2+ Lu3Al5O 12 :Ce 3+ Y3Al5O 12 :Ce 3+ BaSrSiO4:Eu 2+ BaSr2SiO5:Eu 2+ SrAlSiN3:Eu 2+ K2SiF6:Mn 4+ β-SiAlON:Eu 2+ It can efficiently disperse various commercial phosphors with a loading of 0.5–4 wt%, without agglomeration or efficiency loss.

[0027] 3. Significantly improved quantum efficiency and light output

[0028] Traditional glass composite materials generally have a quantum efficiency of <80% (such as silicone resin encapsulation systems), and attenuation >40% under high-power lasers. The narrowband emitting phosphor-glass composite material of this invention achieves an internal quantum efficiency of 87-95% (K2SiF6:Mn). 4+ The percentage was 94.6%, β-SiAlON:Eu 2+ (87.8%), at 50W / mm 2 The light flux under laser excitation reaches 4770 lm (green light) and 684 lm (red light).

[0029] 4. Optimization of thermal conductivity and dynamic thermal management capabilities

[0030] Organic resins have low thermal conductivity (0.2 W·m). -1 ·K -1Previously, complex heat dissipation structures were required. The thermal conductivity of the narrowband phosphor-glass composite material of this invention is improved to 0.5–1.0 W·m. -1 ·K -1 Combined with high-speed fluorescent wheel rotation (≥7200rpm), the surface temperature is ≤85℃ (50W laser load), requiring no additional cooling system.

[0031] 5. Breakthrough in color gamut coverage and display performance

[0032] YAG:Ce 3+ The existing system's color gamut only covers 103% of the Rec.709 standard, and the insufficient red light component results in a cool image. The narrowband red / green composite system of this invention covers 125% of the Rec.709 color gamut, displaying high color saturation and no speckle, making it suitable for high-end display scenarios such as IMAX cinemas, AR / VR immersive displays, and high-brightness engineering projections. Attached Figure Description

[0033] Figure 1 This is a photograph of the 60 mol% SnF2-10 mol% NaF-30 mol% P2O5 glass matrix synthesized in Example 1.

[0034] Figure 2 K2SiF6:Mn 4+ Phosphor and β-SiAlON:Eu 2+ Phosphor, K2SiF6:Mn prepared by the rapid synthesis method in Example 2 4+ Phosphor-glass composites and β-SiAlON:Eu 2+ Excitation and emission spectra of phosphor-glass composite materials.

[0035] Figure 3 K2SiF6:Mn prepared by the rapid synthesis method in Example 2 4+ Internal and external quantum efficiency diagrams of phosphor-glass composite materials.

[0036] Figure 4 β-SiAlON:Eu prepared by the rapid synthesis method in Example 2 2+ Internal and external quantum efficiency diagrams of phosphor-glass composite materials.

[0037] Figure 5 The glass matrix synthesized in Example 1 and the K2SiF6:Mn prepared by the rapid synthesis method in Example 2 are compared. 4+ Phosphor-glass composites and β-SiAlON:Eu 2+ Thermal conductivity diagram of phosphor-glass composite material.

[0038] Figure 6Infrared thermal images of the fluorescent rotating wheel prepared in Example 3 under different laser power densities.

[0039] Figure 7 K2SiF6:Mn prepared in Example 3 4+ Lumen variation of the fluorescent rotor under different laser power densities.

[0040] Figure 8 β-SiAlON:Eu prepared in Example 3 2+ Lumen variation of the fluorescent rotor under different laser power densities.

[0041] Figure 9 β-SiAlON:Eu prepared by the rapid synthesis method in Example 3 2+ Phosphor-glass composite material with K2SiF6:Mn 4+ Laser characterization results of a colored fluorescent rotating wheel prepared by integrating phosphor-glass composite materials.

[0042] Figure 10 This is a schematic diagram of a laser fluorescence display system built based on the colored fluorescent rotating wheel prepared in Experiment Example 4.

[0043] Figure 11 The color gamut diagram of the colored fluorescent wheel prepared in Experiment Example 4. Detailed Implementation

[0044] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading this invention, any modifications to the invention by those skilled in the art in various equivalent forms will fall within the scope defined by the appended claims.

[0045] Example 1 (Glass Matrix Synthesis)

[0046] The mass of the corresponding raw materials was calculated based on the composition 60 mol% SnF2 - 10 mol% NaF - 30 mol% P2O5, where SnF2 and NaF were introduced in the form of their respective oxides and fluorides, and P2O5 was introduced in the form of phosphates. First, the raw materials SnF2, NaF, and NH4H2PO4 were weighed separately, precisely according to the stoichiometric ratio of 60 mol%: 10 mol%: 60 mol% for SnF2, NaF, and NH4H2PO4, ensuring an error within ±0.1% to guarantee the accuracy of the glass composition. Then, these raw materials were placed in an agate mortar and thoroughly mixed for at least 30 minutes to ensure uniform mixing. The mixed raw materials are placed in a corundum crucible and then placed in a muffle furnace. The mixture is heated to 350°C at a heating rate of 10°C / min and held at this temperature for 15 minutes to ensure complete melting and decomposition of NH4H2PO4. Simultaneously, the fluidity and uniformity of the molten glass are observed to ensure a good molten state. Subsequently, the molten glass is quickly poured into a graphite mold preheated to the same temperature and allowed to cool naturally to room temperature. This prevents stress or cracking due to excessive temperature differences, resulting in a transparent glass matrix without obvious bubbles. Figure 1 As shown. The melting point of this glass matrix is ​​280–350℃.

[0047] Example 2

[0048] The glass matrix obtained in Example 1 was placed back into an agate mortar and ground thoroughly for at least 2 hours, passing through a 150-mesh sieve periodically during the grinding process to obtain low-temperature glass powder with uniform particle size. An appropriate amount of glass powder was weighed (according to the ratio of glass powder to β-SiAlON:Eu). 2+ The phosphor mass ratio is 98:2, 98.5:1.5, 99:1, 99.5:0.5, or glass powder and K2SiF6:Mn. 4+ Phosphors with mass ratios of 96:44, 97:3, 98:2, and 99:1 were weighed out and placed in a crucible. The glass powder was heated to 350°C at a rate of 10°C per minute and held at 350°C for 15 minutes to ensure complete melting into a homogeneous melt. Then, the weighed commercially available β-SiAlON:Eu... 2+ Phosphor or K2SiF6:Mn 4+ The phosphor was rapidly poured into the glass melt and stirred quickly with a quartz glass rod at 8 rpm for 10 seconds to ensure uniform dispersion of the phosphor in the glass melt. The homogeneous melt was then rapidly poured into a preheated graphite mold and allowed to cool naturally to room temperature to obtain the corresponding phosphor-glass composite material. β-SiAlON:Eu 2+ Phosphor and K2SiF6:Mn 4+The spectra of the phosphor-glass composite material are basically consistent with those of the individual phosphors, such as... Figure 2 As shown. Furthermore, fluorescence efficiency testing revealed that the luminescence efficiency of the composite material was almost unaffected, K2SiF6:Mn 4+ The highest was 94.6%, β-SiAlON:Eu 2+ The highest value was 87.8%, indicating that β-SiAlON:Eu 2+ With K2SiF6:Mn 4+ Successfully and uniformly composited into an ultra-low melting point glass matrix, such as Figure 3 , Figure 4 As shown. More importantly, as Figure 5 As shown, the thermal conductivity of the material was successfully increased to 0.7 W·m by combining phosphor with a glass substrate. -1 ·K -1 It is several times that of organic resins.

[0049] Example 3

[0050] The K2SiF6:Mn prepared in Example 2 4+ Phosphor-glass composites and β-SiAlON:Eu 2+ The phosphor-glass composite material is processed into discs with a diameter of 50mm. A hole with an inner diameter of 30mm is drilled in the center of each disc, and the disc is fixed to a rotating wheel bracket via a motor shaft. UV-curable adhesive is used to bond the glass-phosphor composite material to the metal disc, ensuring the stability of the rotating wheel during high-speed rotation. Figure 6 As shown, by combining high-speed phosphor wheel rotation, the surface temperature remains ≤85℃ under a 50W laser load. Furthermore, neither phosphor wheel exhibited laser saturation at such a high laser power density. Specifically, the phosphor wheel loaded with 2wt% K₂SiF₆:Mn... 4+ The phosphor-glass composite material has the highest luminous flux, reaching 683 lumens, such as... Figure 7 As shown; loaded with 2wt% β-SiAlON:Eu 2+ The phosphor-glass composite material has the highest luminous flux, reaching 4770 lumens, such as... Figure 8 As shown.

[0051] Example 4

[0052] Based on the requirements of laser display systems, a patterned layout of the rotating wheel is designed, typically alternating red and green light regions to achieve efficient light mixing. K2SiF6:Mn 4+ Phosphor-glass composite material (red light emission) and β-SiAlON:Eu 2+Phosphor-glass composite materials (green light emitting) were separately processed into fan-shaped blocks. High-precision cutting tools were used to cut the two materials into the required shapes and sizes. The two PGC materials were then joined together using UV-cured adhesive (the fan-shaped areas of the two PGCs were identical, and their dimensions were kept consistent), ensuring a smooth interface free of bubbles and gaps to guarantee uniform light output, thus producing a colored phosphor wheel (50mm in diameter). During the joining process, the design pattern was strictly followed to ensure precise arrangement of each color area, thereby achieving uniform mixing of red and green light during high-speed rotation. Figure 9 As shown, the spliced ​​colored rotating wheel can withstand 50W laser irradiation without saturation, and the intensity of green and red light excited by blue laser is basically the same.

[0053] Example 5

[0054] like Figure 10 As shown, we have built a laser phosphor display system, using... A NUBM38 455nm blue laser diode is used to form a parallel beam through a collimating lens group. A dichroic mirror is configured to project the blue laser onto a colored phosphor wheel prepared in Experiment 4, thereby exciting red / green fluorescence and reflecting the emitted fluorescence light and residual blue light, which ultimately mix to form white light. The wheel achieves dynamic thermal management through high-speed rotation (≥7200 rpm). Adjusting the laser power and the wheel's rotation speed optimizes the light output efficiency and color gamut performance. Figure 11 As shown, a blue laser is projected onto the colored phosphor wheel prepared in Experiment 4. This narrow-band red / green composite system covers 125% of the Rec.709 color gamut. The display exhibits high color saturation and no speckle. This invention, through patterned design and dynamic thermal management, ensures stable operation of the system under high-power lasers without laser saturation. Optimizing the angle and position of the beam splitter improves light utilization and display effect, thereby forming a high-quality display image on the screen. This is suitable for high-end display scenarios such as IMAX cinemas, AR / VR immersive displays, and high-brightness engineering projections.

[0055] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A narrow-band phosphor-glass composite material, characterized in that, It includes an ultra-low melting point fluoride glass matrix and a phosphor, with the phosphor dispersed in the ultra-low melting point glass matrix; the glass matrix is ​​an ultra-low melting point glass matrix based on the SnF2-NaF-P2O5 system, with a melting point as low as 280-350℃.

2. The narrow-band phosphor-glass composite material according to claim 1, characterized in that, The composition of the ultra-low melting point glass matrix includes 55-60 mol% stannous fluoride, 5-10 mol% sodium fluoride, and 30-40 mol% phosphorus pentoxide.

3. The narrow-band phosphor-glass composite material according to claim 1, characterized in that, The phosphor is selected from BaMgAl 10 O 17 Eu 2+ Lu3Al5O 12 :Ce 3+ Y3Al5O 12 :Ce 3+ BaSrSiO4:Eu 2+ BaSr2SiO5:Eu 2+ SrAlSiN3:Eu 2+ K2SiF6:Mn 4+ β-SiAlON:Eu 2+ At least one of them.

4. The method for preparing the narrowband emitting phosphor-glass composite material according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Mix SnF2, NaF and NH4H2PO4 in a certain proportion to form glass powder, grind and melt to obtain glass melt; (2) Add the narrow-band phosphor to the glass melt and stir to achieve uniform dispersion; (3) The mixture is quickly poured into a mold and quenched in air to obtain the narrow-band emitting phosphor-glass composite material.

5. The method for preparing narrowband emitting phosphor-glass composite material according to claim 4, characterized in that, In step (1), the molar ratio of SnF2, NaF and NH4H2PO4 is (55-60):(5-10):(30-40).

6. The method for preparing narrowband emitting phosphor-glass composite material according to claim 4, characterized in that, In step (2), the mass ratio of the glass powder to the narrowband phosphor is (96-99.5):(0.5-4).

7. The method for preparing narrowband emitting phosphor-glass composite material according to claim 4, characterized in that, In step (2), melt at 280-350°C for 15-20 minutes.

8. The method for preparing narrowband emitting phosphor-glass composite material according to claim 4, characterized in that, In step (2), stir at a speed of 1 to 5 revolutions per second for 5 to 10 seconds.

9. The application of the narrowband emitting phosphor-glass composite material according to any one of claims 1-3 in the preparation of laser phosphor rotors.

10. The application of the narrowband emitting phosphor-glass composite material according to any one of claims 1-3 in the integration of laser phosphor display systems.

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