A lithium-aluminum-silicon photosensitive glass and a method for preparing the same, cover glass, and electronic device

Abstract

The application discloses lithium-aluminum-silicon photosensitive glass, belonging to the field of new materials, and its components are expressed by weight percentage, containing SiO2: 50-65wt%, Al2O3: 12.1-19wt%, Li2O: 8-18wt%, ZrO2: 3-8wt%, R2O: 4-11wt%, CeO2: 0.01-0.6wt%, Ag2O: 0.25-0.7wt%, Sb2O3: 0.2-1wt%, RO: 0-3wt%, the R2O is one or both of Na2O and K2O, and the RO is alkaline earth metal, wherein the mass ratio of Ag2O / CeO2 is 2.6-3.5.

Description

Technical Field

[0001] This invention belongs to the field of new materials, specifically relating to a lithium aluminum silicon photosensitive glass and its preparation method, cover glass, and electronic devices. Background Technology

[0002] Compared to traditional glass materials, Li2O-Al2O3-SiO2-based photosensitive glass not only possesses superior mechanical strength and dielectric properties but also exhibits photochemical processing characteristics. Therefore, fine microstructures can be fabricated on the surface or within the photosensitive microcrystalline glass using photolithography and wet etching processes. This allows lithium aluminum silicon-based photosensitive microcrystalline glass to serve as a high-performance substrate material, widely applicable in communications, aerospace, and consumer electronics fields.

[0003] In UV-exposed areas, Li₂O-Al₂O₃-SiO₂-based photosensitive glass containing Ag undergoes a color change from transparent to significantly reduced optical transmittance due to the precipitation and growth of colloidal Ag crystals and lithium silicate crystals. This effect serves as a shield for optical signals. Blood oxygen monitoring is a common function of watches, detecting blood oxygen saturation by emitting infrared light that penetrates the skin. Besides high transmittance, the transparent areas of the watch back cover need to prevent light leakage between them, which could interfere with light signal reception. Currently, the back covers used in the market are still made of glass and sapphire, both of which cannot completely avoid light leakage, leading to inaccurate blood oxygen detection. Photosensitive glass, through a shielding process, selectively blackens specific areas, better blocking the infrared band and effectively solving the above problems.

[0004] Although existing photosensitive glass has an inherent advantage in light transmission due to its photochemical processing properties, its impact resistance is weaker than that of sapphire and GG3. Its multiphase microstructure and lack of an effective surface compressive stress layer make it difficult to resist impacts as effectively as sapphire or chemically strengthened glass. Summary of the Invention

[0005] Generally, to improve the mechanical properties of glass, one would consider increasing the alumina content. However, while increasing the alumina content strengthens the glass network, it also inhibits photosensitivity—particularly the formation of silver nanoparticles and the induced crystallization of the glass. This results in reduced light scattering and absorption in the exposed areas, leading to higher transmittance. This invention improves the drop ball performance of the glass by adjusting and optimizing the composition design to increase the proportion of Al2O3 in the glass, while maintaining low transmittance in the blackened areas.

[0006] The specific technical solution of this invention is as follows: a lithium aluminum silicon photosensitive glass, the composition of which is expressed as a weight percentage, contains SiO2: 50-65wt%, Al2O3: 12.1-19wt%, Li2O: 8-18wt%, ZrO2: 3-8wt%, R2O: 4-11wt%, CeO2: 0.01-0.6wt%, Ag2O: 0.25-0.7wt%, Sb2O3: 0.2-1wt%, RO: 0-3wt%, wherein R2O is one or both of Na2O and K2O, and RO is an alkaline earth metal, wherein the mass ratio of Ag2O / CeO2 is 2.6-3.5. In some embodiments, the mass ratio of Ag2O / CeO2 is 2.6 or 2.7 or 2.8 or 2.9 or 3 or 3.1 or 3.2 or 3.3 or 3.4 or 3.5 or any value between the two aforementioned values; In some embodiments, the SiO2 content is 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, 56 wt%, 57 wt%, 58 wt%, 59 wt%, 60 wt%, 61 wt%, 62 wt%, 63 wt%, 64 wt%, or 65 wt%, or any value between the two aforementioned values; the Al2O3 content is 12.1 wt%, 12.5 wt%, 13 wt%, 13.5 wt%, 14 wt%, 14.5 wt%, 15 wt%, 15.5 wt%, 16 wt%, 16.5 wt%, 17 wt%, 17.5 wt%, 18 wt%, 18.5 wt%, or 19 wt%, or any value between the two aforementioned values; The SiO2 / Li2O mass ratio is 4.3-8. In some embodiments, the SiO2 / Li2O mass ratio is 4.3 or 4.4 or 4.5 or 4.6 or 4.7 or 4.8 or 4.9 or 5 or 5.1 or 5.2 or 5.3 or 5.4 or 5.5 or 5.6 or 5.7 or 5.8 or 5.9 or 6 or 6.1 or 6.2 or 6.3 or 6.4 or 6.5 or 6.6 or 6.7 or 6.8 or 6.9 or 7 or 7.1 or 7.2 or 7.3 or 7.4 or 7.5 or 7.6 or 7.7 or 7.8 or 7.9 or 8 or any value between the two aforementioned values. The mass ratio of Al2O3 / (Na2O+K2O+Li2O) is 0.7-1. In some embodiments, the mass ratio of Al2O3 / (Na2O+K2O+Li2O) is 0.7 or 0.75 or 0.8 or 0.85 or 0.9 or 0.95 or 1 or any value between the two aforementioned values.

[0007] The transmittance of the photosensitive glass in the exposure area is 0.2-0.7% at a wavelength of 780nm and 2.7-4.2% at a wavelength of 940nm.

[0008] The drop height of the 150g steel ball in the photosensitive glass is 110-150cm.

[0009] A method for preparing lithium aluminum silicon photosensitive glass includes the following steps: Step 1: The raw materials are prepared and mixed evenly, melted at high temperature and cast into shape, and then annealed and cut to obtain the glass substrate; Step 2: The glass substrate obtained in Step 1 is subjected to ultraviolet exposure masking treatment, and then crystallized in a crystallization furnace to obtain photosensitive glass; Step 3: After CNC polishing and edge-sweeping of the photosensitive glass obtained in Step 2, the photosensitive glass sheet is put into a strengthening furnace for ion exchange.

[0010] The raw materials in step 1 are: SiO2: 50-65wt%, Al2O3: 12.1-19wt%, Li2O: 8-18wt%, ZrO2: 3-8wt%, R2O: 4-11wt%, CeO2: 0.01-0.6wt%, Ag2O: 0.25-0.7wt%, Sb2O3: 0.2-1wt%, RO: 0-3wt%. The R2O is one or both of Na2O and K2O, and the RO is an alkaline earth metal, preferably CaO. The mass ratio of Ag2O / CeO2 is 2.6-3.5.

[0011] The ultraviolet exposure treatment process in step 2 is as follows: the glass slide is irradiated with ultraviolet light with a wavelength of 280-360nm, more preferably 300-330nm, and even more preferably 310nm, for a preferred irradiation time of 5-60 minutes; the crystallization treatment process is preferably a three-stage crystallization treatment: the first crystallization process is to keep the glass slide at 450℃ for 4 hours, the second crystallization process is to keep the glass slide at 530℃ for 2 hours, and the third crystallization process is to keep the glass slide at 610℃ for 1-2 hours.

[0012] The strengthening process in step 3 involves immersing the photosensitive microcrystalline glass in a salt bath of molten Na salt and / or K salt at a temperature of 350℃~450℃ for 1~8 hours, at a temperature of 380℃~440℃ for 2~6 hours.

[0013] A cover glass comprising the aforementioned lithium aluminum silicon photosensitive glass.

[0014] An electronic device comprising the aforementioned lithium aluminum silicon photosensitive glass.

[0015] The photochemical processing properties of photosensitive glass-ceramics originate from trace amounts of photosensitizers (CeO2), nucleating agents (Ag2O), and weak reducing agents (Sb2O3) in their glass composition. Among these, the photosensitizing cerium ions are mainly composed of CeO2. 3+ and Ce4+ Ce exists in the form of glass network, while the weak reducing agent Sb2O3 maintains Ce 3+ The relative content of Sb is shown in formula Sb. 3+ +2Ce 4+ →Sb 5+ +2Ce 3+ .

[0016] Under ultraviolet light (approximately 312 nm), Ce 3+ The absorption of photon energy releases free electrons, as shown in the equation: Ce 3+ +hv→Ce 4+ +e - The electron is captured by color centers or other structures in the glass network and remains in Ce. 4+ Surroundings. During the heat treatment process, Ag ＋ It combines with a free electron to form a silver atom, as shown in the formula: Ag ＋ +e - →Ag ０ Multiple silver atoms diffuse and aggregate to form colloidal silver nanoparticles, as shown in the formula: nAg ０ →Ag ０ In the glass network structure, colloidal silver particles act as nucleating agents, inducing the growth of the lithium metasilicate crystalline phase. In diluted HF solution, the dissolution rate of the lithium metasilicate crystalline phase is approximately 30 times that of the glass phase. Therefore, the lithium metasilicate crystalline phase in the exposed areas is preferentially etched away (see the following formula), while the unexposed areas are retained, thus fabricating a specific structure composed of the glass phase.

[0017] 6HF+Li2O·SiO2→2LiF+SiF4↑+3H20 SiF4 + 2HF → H2SiF6 4HF+SiO2→SiF4↑+2H2O The framework of glass is a three-dimensional disordered network formed by silicon dioxide, with the basic unit being the [SiO4] tetrahedron, connected by bridging oxygen (one oxygen atom connecting two silicon atoms). The addition of aluminum oxide allows for the connection of elements such as Li... + Na + K + Ca 2+ The Al-O bonds pair up and enter the glass network structure, forming a [AlO4]-[SiO4] mixed network. The bond energy of the Al-O bond (~511 kJ / mol) is higher than that of the Si-O bond (~460 kJ / mol), resulting in a denser and more complete glass network topology. [AlO4] acts as a "reinforcing node" in the silicon-oxygen network. Furthermore, during ion exchange, due to the pairing of Al... 3+ This results in a large amount of Li in the glass to balance the charge. + Na+ This provides more exchange sites during the enhancement process, in addition to the effects of Al 3+ The reinforced, dense, and robust network structure can withstand the enormous compressive stress caused by differences in ion size without breaking. All of the above reasons lead to an increase in the Al content of the glass, which can improve its impact resistance.

[0018] While increasing Al content improves the impact resistance of glass, as the Al2O3 content gradually increases, more Li is needed to integrate it into the network structure. + Na + K + Alkali metals are used to balance charges and restrict their movement, which is detrimental to the formation of the crystalline phase (Li₂SiO₃). This leads to reduced transmittance in the blackened portion of the photosensitive microcrystalline glass and makes blackening difficult. Therefore, it is necessary to increase the alkali metal content accordingly to ensure sufficient alkali metals without affecting the formation of the crystalline phase (Li₂SiO₃) and thus the transmittance after blackening. When the Al₂O₃ content is below 12.1 wt%, the hardness and Young's modulus of the glass decrease, and the drop ball height decreases. When the Al₂O₃ content is above 19 wt%, it is detrimental to crystal formation. The Al₂O₃ content range is 12.1–19 wt%.

[0019] Quartz glass's network structure is primarily composed of strong Si-O-Si bridged oxygen bonds, giving it excellent dielectric properties, stability, and a low coefficient of thermal expansion, making it considered an ideal glass structure. However, pure quartz glass lacks photosensitive properties and has a very high melting point, increasing the difficulty of melting. Lithium-aluminum-silicon (LiAlSi) glass addresses this deficiency. By adding oxides containing alkali metals such as Li, Na, and K, Li... + Because the cation field strength is relatively large, it mainly plays an "accumulation" role in the glass network, while Na... + K + The main function is "fracture," breaking bridging oxygen bonds to form non-bridging oxygen bonds. SiO2 and Li2O are the main components forming the crystals of photosensitive microcrystalline glass. When the SiO2 content is less than 50 wt%, the hardness of the glass decreases; when the SiO2 content is higher than 80 wt%, the transmittance of the blackened portion of the photosensitive microcrystalline glass and its products increases. Therefore, the SiO2 content range is 50–75 wt%. When the Li2O content is less than 5 wt%, the addition of network modifier ions (such as Na+) is required for the photosensitive microcrystalline glass or the alumina in its production. + Ca 2+ The crystal content of the compound is reduced, and the transmittance of the blackened part is higher. When the Li2O content is greater than 20wt%, the glass in the part of the photosensitive glass that has not been exposed to ultraviolet light during the crystallization process is prone to crystallization during the heat treatment process. Due to the excessively fine grains, the blackening effect may not be achieved. Therefore, the Li2O content range is 8 to 18wt%.

[0020] Alkali metal oxides (R₂O, which can be one or both of Na₂O and K₂O) can improve glass forming properties and promote the precipitation of Li₂SiO₃ crystals. When the R₂O content is less than 2.5 wt%, it is not conducive to crystal formation, the transmittance of the blackened portion increases, and the blackening effect cannot be achieved. When the R₂O content is greater than 10 wt%, it is not conducive to increasing the drop ball height, and the glass is prone to forming other crystals such as Na₂SiO₃ and K₂SiO₃. Therefore, the R₂O content range is 4–8 wt%.

[0021] ZrO2 can improve crystallization properties and refine grain size. When the ZrO2 content is below 1 wt%, the unexposed areas of the glass tend to crystallize during heat treatment, leading to a decrease in the transmittance of the transparent areas. When the ZrO2 content is above 10 wt%, the crystal content of photosensitive glass-ceramics and photosensitive glass-ceramic products decreases, and the transmittance of the blackened areas increases. Therefore, the ZrO2 content range is 3–8 wt%.

[0022] CeO2 is used as a photosensitizer; the photosensitizing cerium ions are expressed as Ce. 3＋ and Ce 4+ It exists in the form of Ag in the glass network. + Provides electrons. When the CeO2 content is below 0.01 wt%, it cannot provide enough electrons, resulting in an excessively low crystal content. When the CeO2 content is above 0.6 wt%, the penetration depth in the ultraviolet band decreases, the crystal content inside the blackened part of the photosensitive microcrystalline glass decreases, and the transmittance increases. Therefore, the CeO2 content range is 0.01–0.6 wt%.

[0023] Ag₂O acts as a nucleating agent, improving the blackening effect in photosensitive microcrystalline glass. When the Ag₂O content is below 0.1 wt%, the transmittance of the blackened portion of the photosensitive microcrystalline glass increases, or even fails to blacken; when the Ag₂O content exceeds 0.8 wt%, the transmittance of the transparent portion decreases during glass forming or heat treatment. Therefore, the Ag₂O content range is 0.25–0.7 wt%.

[0024] The weak reducing agent Sb₂O₃ maintains Ce 3+ The relative content of Ag plays a role in storing electrons, which is then used for the subsequent heat treatment process. + Electrons are provided to form Ag colloid nuclei, promoting the blackening of photosensitive glass-ceramics. When the Sb₂O₃ content is below 0.05 wt%, the photosensitive glass-ceramics or photosensitive glass-ceramic products are difficult to achieve a blackening effect. When the Sb₂O₃ + SnO₂ content is above 1 wt%, the blackened portion of the photosensitive glass-ceramics or photosensitive glass-ceramic products tends to have increased transmittance. Therefore, the Sb₂O₃ content range is 0.2–1 wt%.

[0025] Alkaline earth metals can reduce the dielectric constant and dielectric loss of photosensitive glass-ceramics; therefore, the RO content ranges from 0 to 3 wt%.

[0026] This invention improves the mechanical properties of photosensitive microcrystalline glass by increasing the Al2O3 content in the glass system, while controlling the mass ratios of Ag2O / CeO2, SiO2 / Li2O, and Al2O3 / (Na2O+K2O+Li2O) within reasonable ranges, thus ensuring both mechanical properties and photosensitivity. Specifically, Al2O3 / (Na2O+K2O+Li2O) determines the structural framework: traditional photosensitive glasses have low aluminum content because Al... 3+ This can lead to the loss of free oxygen, resulting in an overly compact structure that hinders silver ion migration. However, in the system of this invention, a reasonable aluminum-alkali ratio is used to ensure that the alkali metal oxide provides sufficient free oxygen, thus preventing excess Al from being absorbed by the oxygen. 3+ It is converted into tetracoordinated aluminum [AlO4]. - They are embedded in the silicon-oxygen framework. This significantly improves hardness and bending strength without blocking ion channels, leaving room for migration during subsequent heat treatment.

[0027] The Ag₂O / CeO₂ ratio determines photosensitivity: CeO₂ is the photosensitizer, Ag₂O₂... + It is a reduction product. But Ce 4+ It has extremely strong oxidizing properties. If the Ag₂O / CeO₂ ratio is too low, the electrons generated during exposure will be absorbed by the excess CeO₂. 4+ Excessive consumption prevents the formation of silver clusters; if the ratio is too high, silver particles will spontaneously precipitate in unlit glass, making the glass cloudy. Controlling the ratio within a specific range ensures that just enough silver atoms are produced in the illuminated area to form latent nuclei, while the dark area remains stable in an ionic state.

[0028] The SiO2 / Li2O ratio (silicon-lithium ratio) – by properly controlling this ratio, we can ensure that the main components of the matrix fall precisely into the stoichiometric window of the target crystal phase, while colloidal silver provides local nucleation sites. The chemical driving force and the interfacial driving force are superimposed to achieve selective crystallization in the illuminated area and the maintenance of the glassy state in the dark area.

[0029] Aluminum-alkali ratio (≤1) ensures Al 3+ Embedded in a four-coordinate framework, it avoids electrostatic adsorption of three-coordinate aluminum, opening migration channels for silver ions; ensuring that the main matrix components accurately fall into the stoichiometric window of the target crystal phase; the silver-cerium ratio directly matches the photochemical reaction stoichiometric equilibrium, ensuring that the free electrons generated by light can precisely convert Ag. + Restored to Ag 0 The latent core has no excess electrons that cause spontaneous reduction in the dark area. The synergy of these three elements provides a precise physicochemical window within a rigid network reinforced with high alumina, thus balancing mechanical strength and photosensitivity. Attached Figure Description

[0030] Figure 1 This is a SEM image of the photosensitive glass after blackening according to Embodiment 1 of the present invention; Figure 2 This is an image of the photosensitive glass after blackening according to Embodiment 1 of the present invention; Figure 3 This is the XRD pattern of the photosensitive glass after blackening according to Embodiment 1 of the present invention; Figure 4 This is a SEM image of the photosensitive glass after blackening according to Embodiment 3 of the present invention; Figure 5 This is the XRD pattern of the photosensitive glass after blackening according to Embodiment 3 of the present invention; Figure 6 This is a SEM image of the photosensitive glass after blackening according to Embodiment 5 of the present invention; Figure 7 This is a SEM image of the photosensitive glass after blackening, which is the comparative example 1 of this invention. Figure 8 This is the XRD pattern of the photosensitive glass after blackening, as shown in Comparative Example 1 of this invention. Figure 9 This is an image of the photosensitive glass after it has been blackened, as shown in Comparative Example 1 of this invention. Figure 10 This is an image of the photosensitive glass after it has been blackened, which is Comparative Example 3 of this invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Reasonable glass sintering temperature profile and annealing temperature profile are prerequisites for preparing Li-Al-Si photosensitive glass with stable structure and performance. When the maximum sintering temperature is low (<1450℃), the powder sintering is insufficient and obvious small bubbles will be generated. When the sintering temperature is too high and the holding time is too long, Ag element precipitation will occur, resulting in yellow precipitate.

[0033] The glass melting process includes the following four stages: Stage 1: The raw materials are uniformly mixed and heated. Before 800-900℃, the raw materials mainly exist in an opaque sintered form composed of silicates and SiO2, and the products include gases such as CO2 and NO2.

[0034] Stage Two: Continue heating the raw materials to 1200-1250℃. The sintered material begins to melt and gradually becomes transparent, but there are a large number of bubbles and streaks in the glass melt, and the composition is not uniform.

[0035] Phase 3: Continue heating the raw materials to 1400-1600℃. The viscosity of the molten glass decreases while releasing gaseous impurities. Maintain this temperature for a period of time to clarify the molten glass.

[0036] Stage 4: Pour the molten glass into a preheated mold to form a glass ingot.

[0037] During the cooling process, stress inevitably forms within the glass matrix due to factors such as the cooling environment and casting techniques. This stress significantly reduces the glass's mechanical strength and can even lead to cracking. To eliminate this stress and improve the uniformity of the glass's chemical composition, the glass needs to be placed in a specific temperature environment and maintained for a sufficient time before being slowly cooled to eliminate stress exceeding permissible limits. This process is called annealing heat treatment. The maximum annealing temperature is 450-550℃, preferably 480-520℃, and the preferred annealing time is 12-24 hours.

[0038] The formed glass ingots need to undergo cold working processes such as cutting, CNC machining, and polishing to obtain glass sheets with a thickness of 148×68×0.6mm.

[0039] The processed glass sheets undergo a blackening treatment. The polished sheet-shaped photosensitive glass samples are then exposed to ultraviolet light from a mercury lamp at a wavelength of approximately 310 nm for 1-60 minutes using a mask. After exposure, the glass sample surface is cleaned and placed in a crystallization furnace for heat treatment. The exposure power, time, and heat treatment temperature all affect the precipitation, growth, and grain shape of Ag and lithium metasilicate, thus influencing the color and transmittance of the photosensitive glass.

[0040] After the blackened glass undergoes surface processing, it can be strengthened. The strengthening process involves immersing the photosensitive microcrystalline glass in a salt bath of molten Na salt, and / or K salt, and / or a mixed Na and K salt at a temperature of 350°C to 450°C for about 1 to 8 hours, preferably at a temperature of 380°C to 440°C, and preferably for a time of 2 to 6 hours.

[0041] The transmittance in this application was measured by a UV-Vis spectrophotometer. The specific method is as follows: The transmittance of the glass was tested as follows: The glass was made into a sample with a thickness of 0.6 mm ± 0.02 mm, and the transmittance of the glass at 780 nm and 940 nm was tested (T780 nm and T940 nm).

[0042] The specific method for testing the drop ball height in this application is as follows: A 148×68×0.6mm sample is placed on a glass bearing fixture, and a 150g steel ball is dropped from a specified height onto the center point once. The maximum drop height that the sample can withstand without breaking is defined as the drop height. Specifically, the test begins at a drop height of 100mm, and without breaking, the height is increased sequentially to 100mm, 200mm, 300mm, 400mm, 500mm, 600mm, 700mm, 800mm, 900mm, 100mm, 1000mm, 1100mm, 1200mm, and above.

[0043] Example 1

[0044] Step 1: Prepare the raw materials: SiO2: 64.44 wt%, Al2O3: 12.1 wt%, Li2O: 11.39 wt%, ZrO2: 5.75 wt%, Na2O: 2.29 wt%, K2O: 3.09 wt%, CaO ： 0.1wt%, CeO2: 0.12wt%, Ag2O: 0.32wt%, Sb2O3: 0.4wt% are mixed evenly, melted and cast at high temperature, and then annealed and cut to obtain glass substrate. The annealing temperature is 490℃. Step 2: The glass substrate obtained in Step 1 is subjected to ultraviolet exposure treatment by masking, and then crystallized in a crystallization furnace to obtain photosensitive glass. The exposure treatment process is as follows; the crystallization process is a three-stage crystallization process: the first crystallization process is to hold at 450℃ for 4 hours, the second crystallization process is to hold at 530℃ for 2 hours, and the third crystallization process is to hold at 610℃ for 1 hour. Step 3: After CNC polishing and edge-sweeping of the photosensitive glass obtained in Step 2, the photosensitive glass sheet is put into a strengthening furnace for ion exchange. The strengthening process is to immerse the photosensitive microcrystalline glass in a salt bath of molten Na salt and / or K salt at a temperature of 350℃~450℃ for 1~8 hours, at a temperature of 380℃~440℃ for 2~6 hours.

[0045] The prepared photosensitive glass was characterized and tested, and its SEM image is shown below. Figure 1 As shown, the actual product is as follows Figure 2 As shown in the figure, its XRD test results are as follows. Figure 3 As shown, by Figure 1-3 It can be seen that the sample in Example 1 contains a lithium silicate crystal with a particle size of about 300nm, various shapes, and a reasonable number. It obstructs light from passing through without consuming too many Ag colloidal particles. Therefore, the blackened sample has low transmittance and a black color.

[0046] Examples 2-5 The main difference from Example 1 is the composition of raw materials in step 1. The composition of raw materials and specific preparation processes of Examples 2-5 are shown in Table 1.

[0047] Comparative Examples 1-8 The main difference from Example 1 is the composition of raw materials in step 1. The composition of raw materials and specific preparation processes of Comparative Examples 1-8 are shown in Tables 2 and 3.

[0048] SEM image of the photosensitive glass after blackening in Example 3 is shown below. Figure 4 The XRD test results are shown in the figure. Figure 5 SEM image of the photosensitive glass after blackening in Example 5 is shown below. Figure 6 The SEM image, XRD pattern, and physical image of the photosensitive glass after blackening in Comparative Example 1 are shown below. Figure 7-9 Comparative Example 3: A picture of the photosensitive glass after blackening is available. Figure 10 .

[0049] Comparing Examples 1-5 with Comparative Examples 1-2 reveals that increasing the alumina content significantly improves the drop ball performance. Examples 1-5 and Comparative Examples 3-4 demonstrate that the Ag₂O / CeO₂ ratio has a significant impact on the transmittance of the exposure area of ​​the final product.

[0050] As can be seen from Comparative Examples 6 and 8, the transmittance of the exposure area of ​​the product prepared with a SiO2 / Li2O ratio that is not within the range required by this application cannot meet the usage requirements.

[0051] As can be seen from Comparative Examples 5 and 7, the transmittance of the exposure area of ​​the product prepared for Al2O3 / (Na2O+K2O+Li2O) ratios that are not within the range required by this application cannot meet the usage requirements.

[0052] Table 1. Raw material composition and performance of products obtained in Examples 1-5

[0053] Table 2. Raw material composition and performance of products in Comparative Examples 1-4

[0054] Table 3. Raw material composition and performance of the products obtained in Comparative Examples 5-8

[0055] Comparative Example 9 Step 1: Prepare the raw materials: SiO2: 57.44wt%, Al2O3: 19.1wt%, Li2O: 11.39wt%, ZrO2: 5.75wt%, Na2O: 2.29wt%, K2O: 3.09wt%, CaO: 0.1wt%, CeO2: 0.12wt%, Ag2O: 0.32wt%, Sb2O3: 0.4wt% are mixed evenly, melted and cast at high temperature, and then annealed and cut to obtain glass substrate. The annealing temperature is 490℃. Step 2: The glass substrate obtained in Step 1 is subjected to UV exposure treatment with a mask, and then crystallized in a crystallization furnace. The exposure treatment process is as follows; the crystallization process is a three-stage crystallization process: the first crystallization process is to hold at 450℃ for 4 hours, the second crystallization process is to hold at 530℃ for 2 hours, and the third crystallization process is to hold at 610℃ for 1 hour. When this step is completed, it is found that almost no crystals are produced, so no further processing is carried out.

Claims

1. A lithium aluminum silicon photosensitive glass, characterized in that, Its composition, expressed as a weight percentage, contains SiO2: 50-65 wt%, Al2O3: 12.1-19 wt%, Li2O: 8-18 wt%, ZrO2: 3-8 wt%, R2O: 4-11 wt%, CeO2: 0.01-0.6 wt%, Ag2O: 0.25-0.7 wt%, Sb2O3: 0.2-1 wt%, RO: 0-3 wt%, wherein R2O is one or both of Na2O and K2O, and RO is an alkaline earth metal, wherein the mass ratio of Ag2O / CeO2 is 2.6-3.

5.

2. The lithium-aluminum-silicon photosensitive glass according to claim 1, characterized in that, The mass ratio of SiO2 to Li2O is 4.3-8.

3. The lithium aluminum silicon photosensitive glass according to claim 1 or 2, characterized in that, The mass ratio of Al2O3 / (Na2O+K2O+Li2O) is 0.7-1.

4. The lithium aluminum silicon photosensitive glass according to claim 3, characterized in that, The transmittance of the photosensitive glass in the exposure area is 0.2-0.7% at a wavelength of 780nm and 2.7-4.2% at a wavelength of 940nm.

5. The lithium aluminum silicon photosensitive glass according to claim 4, characterized in that, The drop height of the 150g steel ball in the photosensitive glass is 110-150cm.

6. A method for preparing lithium aluminum silicon photosensitive glass, characterized in that, Includes the following steps: Step 1: The raw materials are prepared and mixed evenly, melted at high temperature and cast into shape, and then annealed and cut to obtain the glass substrate; Step 2: The glass substrate obtained in Step 1 is subjected to ultraviolet exposure masking and recrystallization treatment to obtain photosensitive glass; Step 3: After CNC polishing and edge-sweeping of the photosensitive glass obtained in Step 2, the photosensitive glass sheet is put into a strengthening furnace for ion exchange.

7. The method for preparing lithium aluminum silicon photosensitive glass according to claim 6, characterized in that, The raw materials in step 1 are SiO2: 50-65wt%, Al2O3: 12.1-19wt%, Li2O: 8-18wt%, ZrO2: 3-8wt%, R2O: 4-11wt%, CeO2: 0.01-0.6wt%, Ag2O: 0.25-0.7wt%, Sb2O3: 0.2-1wt%, RO: 0-3wt%, wherein R2O is one or both of Na2O and K2O, and RO is an alkaline earth metal, wherein the mass ratio of Ag2O / CeO2 is 2.6-3.

5.

8. The method for preparing lithium aluminum silicon photosensitive glass according to claim 6, characterized in that, The strengthening process in step 3 involves immersing the photosensitive microcrystalline glass in a salt bath of molten Na salt and / or K salt at a temperature of 350℃~450℃ for 1~8 hours, at a temperature of 380℃~440℃ for 2~6 hours.

9. A cover glass, characterized in that, Contains the lithium aluminum silicon photosensitive glass as described in claim 1 or 2.

10. An electronic device, characterized in that, Contains the lithium aluminum silicon photosensitive glass as described in claim 1 or 2.

Images