Dual-frequency excited up-conversion luminescence glass-ceramics, preparation method and three-dimensional display device

Abstract

The application discloses a dual-frequency excitation up-conversion luminescence glass ceramic, a preparation method thereof and a three-dimensional display device. The dual-frequency excitation up-conversion luminescence glass ceramic comprises 40-80 mol parts of TeO2, 10-40 mol parts of ZnO, 5-60 mol parts of GeO2, 0.01-5 mol parts of ErF3 and 0.1-10 mol parts of CaF2. The dual-frequency excitation up-conversion luminescence glass ceramic can generate high-brightness and high-contrast green light under the common excitation of near-infrared light of two different wavelengths of 850 nm and 1550 nm, and has high luminescence efficiency, and can be widely applied in the fields of three-dimensional display, solar cell, optical switch and laser.

Description

Technical Field

[0001] This invention belongs to the field of display, specifically relating to dual-frequency excited upconversion light-emitting microcrystalline glass, its preparation method, and a three-dimensional display device. Background Technology

[0002] Upconversion luminescent materials can emit visible light, and even ultraviolet light, when excited by long-wavelength (such as infrared) radiation. Dual-frequency excited upconversion luminescent materials possess the characteristic of two-step addressing, which, combined with various high-speed dynamic stereoscopic images processed by computers, can be addressed within microcrystalline glass, thereby achieving true 3D display. However, existing upconversion luminescent materials prepared from rare-earth ion-doped microcrystalline glass are typically single-frequency excited, and research on the preparation of dual-frequency excited upconversion materials from rare-earth ion-doped microcrystalline glass is lacking. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to propose a dual-frequency excited upconversion luminescent microcrystalline glass, its preparation method, and a three-dimensional display device. This dual-frequency excited upconversion luminescent microcrystalline glass can generate high-brightness and high-contrast green light under the co-excitation of near-infrared light of two different wavelengths (850nm and 1550nm), exhibiting high luminous efficiency. It can be widely used in three-dimensional displays, solar cells, optical switches, and lasers.

[0004] In one aspect of the present invention, a dual-frequency excited upconversion luminescent glass-ceramic is provided. According to an embodiment of the present invention, the dual-frequency excited upconversion luminescent glass-ceramic comprises: 40 to 80 mol parts of TeO2, 10 to 40 mol parts of ZnO, 5 to 60 mol parts of GeO2, 0.01 to 5 mol parts of ErF3, and 0.1 to 10 mol parts of CaF2.

[0005] Compared with existing technologies, this dual-frequency excited upconversion luminescent glass-ceramic has at least the following advantages: 1) The glass-ceramic obtained by using TeO2 and GeO2 as network formers has lower phonon energy, which can effectively improve the luminescence efficiency of the luminescent center; 2) The introduction of rare earth ions Er into the tellurium germanate glass-ceramic... 3+ This gives the glass-ceramic the characteristic of dual-frequency excitation addressing, allowing it to produce high-brightness and high-contrast green light under the co-excitation of near-infrared light at two different wavelengths, 850nm and 1550nm, which can be used for volumetric three-dimensional imaging; 3) Introducing CaF2 into tellurium germanate glass-ceramic, during the annealing microcrystallization process, Er 3+ Ions can replace Ca in CaF2 2+ Ions enter calcium fluoride crystals with a fluorite structure, causing a slight deformation in the crystal's face-centered cubic structure, which becomes the luminescent center Er. 3+Providing an asymmetric microenvironment is beneficial for further improving the upconversion luminescence efficiency of the glass-ceramic. In summary, the dual-frequency excited upconversion luminescent glass-ceramic according to the above embodiments of the present invention can not only emit light under the co-excitation of near-infrared light of two different wavelengths (850nm and 1550nm), but also has high luminescence efficiency, making it widely applicable in fields such as 3D displays.

[0006] In addition, the dual-frequency excited upconversion luminescent glass according to the above embodiments of the present invention may also have the following additional technical features:

[0007] In some embodiments of the present invention, the dual-frequency excited upconversion luminescent microcrystalline glass comprises: 40 to 80 moles of TeO2, 10 to 30 moles of ZnO, 5 to 30 moles of GeO2, 0.01 to 3 moles of ErF3, and 0.1 to 5 moles of CaF2.

[0008] In some embodiments of the present invention, the microcrystalline glass further includes: Li2CO3 and / or Na2CO3.

[0009] In some embodiments of the present invention, the molar ratio of TeO2 to GeO2 is (4-7):1.

[0010] In some embodiments of the present invention, the molar ratio of CaF2 to ErF3 is (2-5):1.

[0011] In some embodiments of the present invention, the Li2CO3 content is 1wt% to 5wt% based on the total mass of the microcrystalline glass.

[0012] In some embodiments of the present invention, the proportion of Na2CO3 is 5wt% to 10wt% based on the total mass of the microcrystalline glass.

[0013] In another aspect of the present invention, a method for preparing the aforementioned dual-frequency upconversion luminescent glass-ceramic is provided. According to an embodiment of the present invention, the method includes: (1) mixing and drying TeO2, ZnO, GeO2, ErF3, and CaF2 according to a specified ratio to obtain a mixed raw material; (2) heating the mixed raw material in an air atmosphere to obtain a mixed glass melt; and (3) molding the mixed glass melt to obtain a dual-frequency upconversion luminescent glass-ceramic. This method is not only simple in process but also yields a dual-frequency excited upconversion luminescent glass-ceramic. This glass-ceramic can emit light under the co-excitation of near-infrared light of two different wavelengths, 850nm and 1550nm, and exhibits high luminous efficiency, making it widely applicable in fields such as three-dimensional displays.

[0014] In some embodiments of the present invention, step (1) includes grinding and mixing.

[0015] In some embodiments of the present invention, the mixing process is carried out in an agate mortar.

[0016] In some embodiments of the present invention, the drying temperature is 100°C to 400°C and the drying time is 1 hour to 5 hours.

[0017] In some embodiments of the present invention, in step (2), the temperature of the heat treatment is 780°C to 1100°C and the time is 10 min to 80 min.

[0018] In some embodiments of the invention, the heat treatment is performed in a platinum crucible.

[0019] In some embodiments of the present invention, step (3) includes the molding process of pouring the molten glass into a mold, annealing it at 280°C to 320°C for 2 to 6 hours, and then performing microcrystallization at 350°C to 415°C.

[0020] In another aspect, the present invention provides a three-dimensional display device. According to an embodiment of the present invention, the three-dimensional display device comprises the above-described dual-frequency excited upconversion light-emitting glass, or a dual-frequency excited upconversion light-emitting glass prepared by the above method. Compared with the prior art, this three-dimensional display device can achieve true three-dimensional display and has higher luminous efficiency.

[0021] In some embodiments of the present invention, in the three-dimensional display device, the laser wavelengths used for dual-frequency excitation are 850 nm and 1550 nm.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0024] Figure 1 This is a flowchart of the preparation of dual-frequency excited upconversion luminescent glass crystal according to an embodiment of the present invention;

[0025] Figure 2 The emission spectra of the microcrystalline glass of Embodiments 1, 5, 6 and Comparative Examples 1 to 3 according to the present invention under co-excitation by near-infrared light at 850 nm and 1550 nm are shown.

[0026] Figure 3These are the emission spectra of the microcrystalline glass according to Embodiments 2-4 of the present invention under co-excitation by near-infrared light at 850 nm and 1550 nm.

[0027] Figure 4 This is a three-dimensional image displayed within the microcrystalline glass body according to Embodiment 1 of the present invention. Detailed Implementation

[0028] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] In one aspect of the present invention, a dual-frequency excited upconversion luminescent microcrystalline glass is provided. According to an embodiment of the present invention, the dual-frequency excited upconversion luminescent microcrystalline glass comprises: 40 mol parts to 80 mol parts of TeO2, for example, 45 mol parts, 55 mol parts, 65 mol parts, or 75 mol parts; 10 mol parts to 40 mol parts of ZnO, for example, 15 mol parts, 20 mol parts, 25 mol parts, 30 mol parts, or 35 mol parts; 5 mol parts to 60 mol parts of GeO2, for example, 10 mol parts, 20 mol parts, 30 mol parts, or 40 mol parts; 0.01 mol parts to 5 mol parts of ErF3, for example, 0.05 mol parts, 0.1 mol parts, 1 mol parts, 2 mol parts, 3 mol parts, or 4 mol parts; and 0.1 mol parts to 10 mol parts of CaF2, for example, 0.5 mol parts, 1 mol parts, 2 mol parts, 4 mol parts, 6 mol parts, 8 mol parts, or 9 mol parts.

[0030] According to the dual-frequency excited upconversion luminescent microcrystalline glass of the present invention, by adding the above-mentioned amount of TeO2, a tellurate glass is formed as the upconversion luminescent material matrix. It has low phonon energy, excellent chemical stability, low melting point and good rare earth solubility. It can effectively overcome the shortcomings of traditional silicate glass or phosphate glass, such as low rare earth doping luminescence efficiency. It is not only beneficial to improve the luminescence efficiency and chemical stability of the dual-frequency excited upconversion luminescent microcrystalline glass, but also beneficial to simplify the preparation process of the microcrystalline glass and improve the solubility and dispersibility of rare earth ions in the glass matrix. In addition, by adding the above-mentioned amount of metal oxides ZnO and GeO2 as network intermediates, it is not only beneficial to improve the thermal stability of the tellurate glass matrix, but also to improve the asymmetry of the environment around the ion luminescence center and improve the luminescence efficiency of the luminescence center. The inventors discovered that in the microcrystalline glass of the above embodiments of the present invention, if the relative content of TeO2 is too low, it is difficult to obtain a luminescent material based on tellurate glass. If the relative content of TeO2 is too high, it will limit the content of other components (such as ZnO, GeO2, etc.) and affect the thermal stability of the microcrystalline glass. If the relative content of ZnO and GeO2 is too low, it will not improve the thermal stability of the microcrystalline glass sufficiently. If the relative content of ZnO and GeO2 is too high, it will be difficult to form a stable tellurate glass. The present invention, by controlling the content of TeO2, ZnO and GeO2 within the above range, is beneficial to balance the luminous efficiency and thermal stability of the microcrystalline glass.

[0031] Furthermore, in this invention, rare earth ions Er are introduced by adding ErF3 at the above-mentioned amount. 3+ This gives the glass-ceramic the characteristic of dual-frequency excitation addressing, allowing it to emit light under the co-excitation of near-infrared light at two different wavelengths, 850nm and 1550nm, which can be used for volumetric 3D imaging. The inventors discovered that in the glass-ceramic of the above embodiments of the present invention, if the relative content of ErF3 is too low, the luminescence intensity of the glass-ceramic under the co-excitation of 850nm and 1550nm near-infrared light will be low; if the relative content of ErF3 is too high, the ErF3 content in the glass-ceramic will be high. 3+ The concentration is high, Er 3+ The interionic spacing is small, Er 3+ Energy transfer can easily occur between them, causing concentration quenching and affecting the luminescence efficiency of the glass-ceramic. This invention controls the content of ErF3 in the glass-ceramic within the above range, which is beneficial to obtaining a dual-frequency excited upconversion luminescent glass-ceramic with high luminescence efficiency and intensity.

[0032] Furthermore, in this invention, by adding the aforementioned amount of CaF2, CaF2 is introduced into the tellurium germanate microcrystalline glass, and during the annealing and microcrystallization process, Er... 3+ Ions can replace Ca in CaF2 2+Ions enter calcium fluoride crystals with a fluorite structure, causing a slight deformation in the crystal's face-centered cubic structure, which becomes the luminescent center Er. 3+ Providing an asymmetric microenvironment is beneficial for further improving the upconversion luminescence efficiency of glass-ceramics. The inventors discovered that in the glass-ceramics of the above embodiments of the present invention, if the relative content of CaF2 is too low, it is difficult to form stable calcium fluoride microcrystals, thus making it difficult to pass through the Er... 3+ The interaction with calcium fluoride crystals improves the luminous efficiency of glass-ceramics; if the relative content of CaF2 is too high, it can easily lead to a decrease in the transparency of glass-ceramics and affect its luminous effect. This invention controls the content of CaF2 in glass-ceramics within the above range, which is beneficial to balance the luminous efficiency and transparency of glass-ceramics.

[0033] According to embodiments of the present invention, the glass-ceramic may include: 40 to 80 moles of TeO2; 10 to 30 moles of ZnO, for example, 12, 18, 24, or 28 moles; 5 to 30 moles of GeO2, for example, 6, 12, 18, 24, or 28 moles; 0.01 to 3 moles of ErF3, for example, 0.02, 0.2, 0.8, 1.2, 1.8, 2.4, or 2.8 moles; and 0.1 to 5 moles of CaF2, for example, 0.2, 0.6, 1.8, 2.4, 3.6, 4.2, or 4.8 moles. This further improves the luminous efficiency and stability of dual-frequency emission of the glass-ceramic.

[0034] According to embodiments of the present invention, the molar ratio of TeO2 to GeO2 in the glass-ceramic can be (4-7):1, for example, it can be 4.5 / 1, 5 / 1, 5.5 / 1, 6 / 1 or 6.5 / 1, etc. The inventors have found that if the molar ratio of TeO2 to GeO2 is too low, the relative content of GeO2 is too high, which will increase the difficulty of firing the glass-ceramic on the one hand, and affect the formation of tellurate glass on the other hand; if the molar ratio of TeO2 to GeO2 is too high, the relative content of GeO2 is too low, which is insufficient to improve the thermal stability and luminous efficiency of the glass-ceramic. The present invention, by controlling the molar ratio of TeO2 to GeO2 within the above range, is beneficial to further improve the luminous efficiency of the glass-ceramic while reducing the firing difficulty and processing stability of the glass-ceramic.

[0035] According to embodiments of the present invention, the molar ratio of CaF2 to ErF3 can be (2-5):1, for example, 2.5 / 1, 3 / 1, 3.5 / 1, 4 / 1, or 4.5 / 1, etc. The inventors have found that if the molar ratio of CaF2 to ErF3 is too small, the relative content of CaF2 is too low, resulting in fewer calcium fluoride crystals formed, and ErF3... 3+ Replace Ca 2+ The entry of calcium fluoride into the crystal is difficult, affecting its promoting effect on upconversion luminescence efficiency. If the molar ratio of CaF2 to ErF3 is too high, excessive CaF2 leads to a decrease in the transparency of the glass-ceramic, affecting its luminescence efficiency and performance. This invention, by controlling the molar ratio of CaF2 to ErF3 within the above-mentioned range, is more conducive to improving the luminescence efficiency and luminescence effect of dual-frequency excited upconversion luminescent glass-ceramics.

[0036] According to embodiments of the present invention, the glass-ceramic may further include Li₂CO₃ and / or Na₂CO₃. The addition of Li₂CO₃ and / or Na₂CO₃ can generate a fluxing effect, which is beneficial for further reducing the firing temperature of the glass-ceramic, thereby reducing the preparation difficulty and processing cost. Further, according to some specific examples of the present invention, based on the total mass of the glass-ceramic, the proportion of Li₂CO₃ can be 1wt% to 5wt%, for example, 1.5wt%, 2.5wt%, 3.5wt%, or 4.5wt%, etc., and the proportion of Na₂CO₃ can be 5wt% to 10wt%, for example, 5.5wt%, 6.5wt%, 7.5wt%, 8.5wt%, or 9.5wt%, etc.

[0037] In another aspect of the invention, a method for preparing the aforementioned dual-frequency upconversion luminescent microcrystalline glass is provided. According to embodiments of the invention, combined with... Figure 1 Understanding, the method includes:

[0038] S100: TeO2, ZnO, GeO2, ErF3, and CaF2 are mixed and dried according to the specified ratio to obtain the mixed raw material.

[0039] According to embodiments of the present invention, the above-mentioned components can be added to a mixing device according to the specified ratio for grinding and mixing. Grinding improves the uniformity of the mixture. Furthermore, a solvent can be added after grinding to form a slurry, further enhancing the dispersion of the components. The present invention does not impose any particular limitation on the specific type of solvent used in the mixing process; those skilled in the art can choose flexibly according to actual conditions, such as ethanol. After the above-mentioned components are mixed uniformly, the mixed raw materials are dried. The drying temperature can be 100℃~400℃, and the time can be 1h~5h. This effectively removes impurities such as water vapor or hydroxyl groups from the mixture, which helps to ensure the purity and luminescence effect of the microcrystalline glass. It should be noted that the present invention does not impose any particular limitation on the mixing device used for the mixing process; for example, the mixing process can be carried out in an agate mortar.

[0040] S200: The mixed raw materials are heated in an air atmosphere to obtain a mixed glass melt.

[0041] According to an embodiment of the present invention, the mixed raw materials obtained in S100 are heated in an air atmosphere. The heating temperature can be 780°C to 1100°C and the time can be 10 min to 80 min, thereby allowing the components to be fully melted to obtain a mixed glass melt. It should be noted that there are no particular restrictions on the material of the specific heating device in the present invention. Those skilled in the art can choose flexibly according to the actual situation. For example, the heating treatment can be carried out in a platinum crucible.

[0042] S300: The mixed glass melt is shaped to obtain dual-frequency upconversion luminescent microcrystalline glass.

[0043] According to an embodiment of the present invention, the mixed glass liquid obtained in S200 is subjected to a molding process. The specific method of molding is not particularly limited in the present invention; those skilled in the art can choose flexibly according to the actual situation. For example, the glass liquid can be poured into a mold for cooling and molding, and then the molding material is annealed at 250°C to 280°C for 2 to 6 hours to eliminate internal stress in the molding material. The inventors have found that if the annealing temperature is too low, the elimination of internal stress is incomplete; if the annealing temperature is too high, the molded material is prone to softening, affecting the molding effect. Then, the annealed material is subjected to a microcrystallization treatment at 350°C to 415°C to form calcium fluoride glassy microcrystals. The purpose of forming calcium fluoride glassy microcrystals has been described in detail in the preceding section and will not be repeated here.

[0044] In summary, the method for preparing dual-frequency upconversion luminescent glass crystals is not only simple in process, but also yields dual-frequency excited upconversion luminescent glass crystals. These glass crystals can emit light under the co-excitation of near-infrared light of two different wavelengths, 850nm and 1550nm, and have high luminous efficiency, making them widely applicable in fields such as 3D displays.

[0045] In another aspect, the present invention provides a three-dimensional display device. According to an embodiment of the present invention, the three-dimensional display device comprises the above-described dual-frequency excited upconversion luminescent glass, or a dual-frequency excited upconversion luminescent glass prepared by the above method. Compared with the prior art, this three-dimensional display device can achieve true three-dimensional display and has higher luminous efficiency. It should be noted that in this three-dimensional display device, the laser wavelengths used for dual-frequency excitation are 850 nm and 1550 nm.

[0046] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0047] Example 1

[0048] (1) Calculate the weight of each component according to the molar percentage of glass composition in Table 1, weigh each raw material component into an agate mortar, grind it thoroughly to make the materials evenly mixed and then dry it.

[0049] (2) The above-mentioned uniformly mixed and dried material is placed into a covered platinum crucible and melted in a box furnace at 900°C for 30 minutes. A uniform, bubble-free glass melt is obtained.

[0050] (3) Pour the molten glass into a preheated mold, quickly transfer the glass into the muffle furnace of the preheated mold, keep it at 300°C for 4 hours, cool it to room temperature with the furnace, take out the glass sample, and anneal and microcrystallize it at 350°C for 4 hours in the muffle furnace to obtain dual-frequency excitation upconversion luminescent microcrystalline glass.

[0051] Examples 2-6

[0052] The differences from Example 1 are shown in Table 1.

[0053] Comparative Examples 1-4

[0054] The differences from Example 1 are shown in Table 1.

[0055] Table 1 shows the content of each component in Examples 1-6 and Comparative Examples 1-4.

[0056]

[0057] Results and Discussion

[0058] Under the same conditions, the dual-frequency excited upconversion luminescent glass-ceramic samples prepared in Examples 1-6 and Comparative Examples 1-4 were polished and then subjected to a two-step dual-frequency excitation test. The test results are as follows: Figures 2-3 As shown, the three-dimensional "cubic prism" pattern displayed within the microcrystalline glass obtained in Example 1 is as follows: Figure 4 As shown, the microcrystalline glass using the above embodiments of this application can generate high-brightness and high-contrast green light under the co-excitation of near-infrared light of two different wavelengths, 850nm and 1550nm, exhibiting high luminous efficiency. It can be widely used in fields such as 3D displays, solar cells, optical switches, and lasers. Specifically, compared to Example 1, Comparative Example 1 did not add CaF2, resulting in a decrease in upconversion luminous efficiency; Comparative Example 2 used excessive ErF3, which also affected the luminous efficiency of the microcrystalline glass. Analysis suggests this is due to excessive ErF3 in the microcrystalline glass. 3+ To make its interionic spacing smaller, Er 3+ Energy transfer can easily occur between them, causing concentration quenching; in Comparative Example 3, although the luminous efficiency did not decrease significantly due to the absence of GeO2, the thermal stability of the glass-ceramic was severely reduced, affecting its performance; in Comparative Example 4, the CaF2 content was too high, making it difficult to obtain transparent glass-ceramic.

[0059] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0060] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A dual-frequency excited upconversion luminescent microcrystalline glass, characterized in that, include: 40-80 mol of TeO2, 10-40 mol of ZnO, 5-30 mol of GeO2, 0.01-5 mol of ErF3, and 0.1-10 mol of CaF2; The molar ratio of TeO2 to GeO2 is (4~7):

1.

2. The microcrystalline glass according to claim 1, characterized in that, include: 10 to 30 moles of the ZnO, 0.01 to 3 moles of the ErF3, and 0.1 to 5 moles of the CaF2; And / or, the microcrystalline glass further includes: Li2CO3 and / or Na2CO3.

3. The microcrystalline glass according to claim 1 or 2, characterized in that, The molar ratio of CaF2 to ErF3 is (2~5):

1.

4. The microcrystalline glass according to claim 2, characterized in that, Based on the total mass of the microcrystalline glass, the Li2CO3 content is 1wt%~5wt%; And / or, based on the total mass of the microcrystalline glass, the Na2CO3 content is 5wt%~10wt%.

5. A method for preparing dual-frequency excited upconversion luminescent glass crystals according to any one of claims 1 to 4, characterized in that, include: (1) Mix and dry the raw materials according to the proportions to obtain the mixed raw materials; (2) The mixed raw materials are heated in an air atmosphere to obtain a mixed glass melt; (3) The mixed glass liquid is subjected to molding treatment to obtain dual-frequency upconversion luminescent microcrystalline glass.

6. The method according to claim 5, characterized in that, In step (1), the mixing process includes grinding and mixing.

7. The method according to claim 6, characterized in that, The mixing process was carried out in an agate mortar.

8. The method according to claim 6, characterized in that, The drying temperature is 100℃~400℃ and the time is 1h~5h.

9. The method according to claim 5, characterized in that, In step (2), the temperature of the heat treatment is 780℃~1100℃ and the time is 10min~80min.

10. The method according to claim 9, characterized in that, The heat treatment is carried out in a platinum crucible.

11. The method according to claim 5, characterized in that, In step (3), the forming process includes: pouring the molten glass into a mold, annealing it at 280℃~320℃ for 2h~6h, and then performing microcrystallization treatment at 350℃~415℃.

12. A three-dimensional display device, characterized in that, It includes the dual-frequency excited upconversion luminescent glass crystal according to any one of claims 1 to 4, or the dual-frequency excited upconversion luminescent glass crystal prepared by the method according to any one of claims 5 to 11.

13. The three-dimensional display device according to claim 12, characterized in that, The laser wavelengths used for dual-frequency excitation are 850nm and 1550nm.

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