Geometric light waveguide glass material with high refractive index and low stray light and preparation process thereof

Abstract

A high-refractive low-stray-light geometric optical waveguide glass material and a preparation process thereof, which comprises, by mass percentage, zinc oxide 15-25%, lanthanum oxide 20-30%, tantalum pentoxide 10-20%, niobium pentoxide 5-15%, boron oxide 10-20%, clarifying agent 0.1-0.5%, and the balance being silicon dioxide. The glass has a refractive index n d of 1.68-1.72, a stray light suppression rate ≥ 90%, a thickness ≤ 1.5 mm, and a total reflection critical angle ≤ 36.5°. The preparation comprises the steps of melting, clarifying, casting forming, annealing, ion exchange, etc. Through optimization of components and coating, the overall transmittance ≥ 85%, the light leakage rate ≤ 10%, the virtual-real fusion effect and the use experience are improved.

Description

Technical Field

[0001] This invention relates to the field of augmented reality technology, specifically to a high-refractive-index, low-stray-light geometric waveguide glass material and its fabrication process. Background Technology

[0002] As a core optical component of AR near-eye display systems, the performance of geometric waveguides directly determines key indicators such as the field of view, image clarity, and brightness uniformity of the display system. Its working principle is based on the law of total internal reflection, achieving the superposition of virtual images and real scenes through beam transmission and coupling within the waveguide. In existing technologies, traditional waveguide materials such as K9 glass (refractive index n...) d =1.52) has significant drawbacks: Firstly, the lower refractive index results in a larger critical angle for total internal reflection (approximately 41°), limiting the expansion of the field of view and making it difficult to meet the display requirements for a large field of view (≥50°×40°); secondly, internal impurities and interface reflections easily generate stray light (such as "blue arcs" and mirror interference), leading to a decrease in image contrast, and the light leakage rate typically exceeds 15%. To improve the field of view, the industry uses high-refractive-index glass such as H-ZF11 (n d =1.70), but existing materials and manufacturing processes have shortcomings. The composition and film system have not been optimized for waveguide applications, resulting in a stray light suppression rate of less than 85% for geometric waveguide glass, which in turn causes ghosting in geometric waveguide displays.

[0003] Therefore, a geometric waveguide glass material with high refractive index and low stray light and its fabrication process are provided to solve the problems mentioned in the background art. Summary of the Invention

[0004] The purpose of this invention is to provide a geometric optical waveguide glass material with high refractive index and low stray light and its preparation process, so as to solve the problem that existing waveguide glass materials are difficult to achieve high refractive index, low stray light and good optical uniformity.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The geometric waveguide glass material provided by this invention comprises, by mass percentage: 18-22% zinc oxide, 23-27% lanthanum oxide, 13-17% tantalum pentoxide, 8-12% niobium pentoxide, 13-17% boron oxide, 0.2-0.4% clarifying agent, and the remainder being silicon dioxide. The purity of the raw materials containing zinc oxide, lanthanum oxide, tantalum pentoxide, niobium pentoxide, boron oxide, and silicon dioxide is ≥99.99%, and the total impurity content is ≤0.01%. The refractive index n of this glass material is... d The Abbe number is 1.68-1.72. The concentration is 35-38, the transmittance in the visible light band is ≥92%, and the stray light suppression rate is ≥90%. The clarifying agent is preferably a combination of antimony trioxide and ammonium chloride, wherein antimony trioxide accounts for 0.15-0.3%, ammonium chloride accounts for 0.05-0.1%, and the total mass percentage of antimony trioxide and ammonium chloride is 0.2-0.4%.

[0007] In terms of the preparation process, the present invention includes the following key steps: placing the uniformly mixed raw materials in a platinum crucible and melting them at 1580-1620℃ for 3-5 hours, using an intermittent stirring process during melting; after cooling to 1450℃, adding a clarifying agent and holding the temperature for clarification for 1 hour, with high-purity anhydrous nitrogen gas introduced during the clarification process; then pouring the mixture into a preheated graphite mold for shaping; after shaping, performing a two-stage annealing treatment, the first stage being held at 500-520℃ for 2.5-3 hours, and the second stage being held at 420-430℃ for 3.5-4 hours; after annealing, the glass substrate is cut, ground, and chemically and mechanically polished, and then placed in an anhydrous potassium nitrate and sodium nitrate composite salt system with a mass ratio of 95:5 at 430-450℃ for ion exchange treatment for 3-4 hours to form a surface compressive stress layer.

[0008] After the above-mentioned process, the geometric waveguide glass material achieves an internal stripe grade of A and an optical uniformity Δn ≤ 5 × 10⁻⁶. -5 The glass has a thickness ≤1.5mm and a critical angle for total internal reflection ≤36.5°. After chemical mechanical polishing, the glass surface has a roughness Ra ≤1nm and is coated with a SiO2 / TiO2 multilayer antireflective film and a Nb2O5 / SiO2 semi-reflective / semi-transparent film stack, with a film thickness of 100-200nm, resulting in an overall transmittance ≥85% and a light leakage rate ≤10%. Ion exchange treatment ensures a surface compressive stress ≥450MPa, a compressive stress layer depth ≥50μm, and a tensile strength of the glass substrate ≥800MPa.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0010] This invention effectively solves the technical problem of stripes and optical inhomogeneity easily generated in high-content La2O3, Ta2O5, and Nb2O5 glasses during thin-plate forming by optimizing the synergistic design of glass composition and two-stage annealing process, achieving Grade A stripe level and Δn≤5×10 -5 The optical uniformity is excellent. By polishing to form an ultra-smooth surface (Ra≤1nm) followed by ion exchange, in synergy with an ultra-thin plate (≤1.5mm), high surface compressive stress and compressive stress layer depth are achieved while maintaining optical performance. Its engineering reliability is verified through bending tests. By depositing antireflective and semi-reflective films on the glass surface, the overall transmittance is ≥85% and the light leakage rate is ≤10%, effectively improving the virtual-real fusion effect and user experience. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the clarifying agent components in this invention;

[0012] Figure 2 This is a schematic diagram of the fabrication process of the geometric optical waveguide glass in this invention;

[0013] Figure 3 This is a schematic diagram of the annealing process in this invention. Detailed Implementation

[0014] Please see Figures 1-3 A high-refractive-index, low-stray-light geometric waveguide glass material, comprising, by mass percentage: zinc oxide: 18-22%, lanthanum oxide: 23-27%, tantalum pentoxide: 13-17%, niobium pentoxide: 8-12%, boron oxide: 13-17%, clarifying agent: 0.2-0.4%, with the remainder being silicon dioxide; the purity of the raw materials of zinc oxide, lanthanum oxide, tantalum pentoxide, niobium pentoxide, boron oxide, and silicon dioxide is ≥99.99%, and the total impurity content is ≤0.01%; the refractive index n of the geometric waveguide glass is... d The Abbe number is 1.68-1.72. The transmittance is ≥92% in the visible light band, and the stray light suppression rate is ≥90% in the visible light band, according to GB / T34185-2017 "Stray Light Test Method for Optical Glass".

[0015] Zinc oxide, as a glass network modifier, not only reduces the viscosity of the glass during melting and significantly improves melt flow, allowing the raw materials to mix more evenly at high temperatures, but also enhances the chemical stability of the glass, making it less prone to corrosion or deterioration in complex environments such as humidity and high temperature, thus extending the service life of the device.

[0016] Lanthanum oxide: As a key high refractive index regulating component in glass materials, the rare earth lanthanum ions it contains have a large ionic radius and polarizability, which can effectively improve the refractive index of the glass. At the same time, the unique electronic structure of rare earth elements can reduce the dispersion of the glass, reduce the color shift when light passes through, ensure the authenticity of the image color, and provide a foundation for high-definition display.

[0017] Tantalum pentoxide: As a high-refractive-index auxiliary component in glass materials, it forms a synergistic effect with niobium pentoxide to further enhance the refractive index of the glass. Furthermore, the introduction of tantalum can suppress the crystallization tendency of the glass during the cooling process, avoiding uneven optical properties caused by crystallization and ensuring the overall uniformity and transparency of the glass.

[0018] Niobium pentoxide: Its unique atomic arrangement structure can also optimize the optical uniformity of glass and reduce microscopic defects inside the material (such as tiny impurities and density fluctuations), thereby reducing the probability of stray light scattering and improving the contrast of the display.

[0019] Boron oxide: As a glass network forger, it can effectively reduce the melting temperature of glass, reduce energy consumption, and at the same time suppress phase separation during the melting and cooling process of glass (i.e., avoid the separation of different components due to differences in solubility), thus ensuring the uniformity of glass composition.

[0020] The clarifying agent uses a composite system of antimony trioxide and ammonium chloride. The gas produced by decomposition at high temperature can promote the aggregation and floating of bubbles, while the volatile gas produced by decomposition can further flush out the tiny bubbles. The synergistic effect of the two can effectively eliminate the bubbles generated during the glass melting process, avoid the scattering of light by the bubbles, and improve the optical purity of the glass.

[0021] Silica: As the basic skeletal component of glass, its continuous network structure is the core of ensuring the mechanical strength and structural stability of glass. It allows glass to maintain sufficient rigidity when processed into ultra-thin waveguides (thickness ≤ 1.5mm), making it less prone to deformation or breakage.

[0022] Among the above components, lanthanum oxide, tantalum pentoxide, and niobium pentoxide have relatively high contents. During the glass melting and cooling process, high field strength ions (La) are present. 3+ Ta 5+ 、Nb 5+ Localized enrichment can easily occur, leading to crystallization tendency and phase separation risk, affecting the optical uniformity of the glass. To address this issue, the fabrication process of this application employs a two-stage annealing treatment: the first stage is held at 500-520℃ for 2.5-3 hours, and the second stage is held at 420-430℃ for 3.5-4 hours. The first stage temperature is significantly higher than the glass transition temperature Tg (430-470℃), with a temperature difference of 70-100℃, which can quickly eliminate the thermal stress generated during glass forming. Simultaneously, controlling the holding time prevents excessive softening and deformation of ultra-thin glass (thickness ≤1.5mm). The second stage temperature is maintained near or slightly below Tg, and the prolonged holding time homogenizes the glass network structure, suppressing the localized enrichment of high-field-strength ions during cooling, thereby reducing the tendency for crystallization and phase separation. The two stages form a stepped temperature difference of approximately 50-100℃, with clear division of labor, ensuring rapid stress elimination while optimizing optical uniformity. After the above-mentioned processing, the geometric waveguide glass material, in a thin plate with a thickness ≤1.5mm, achieves an internal stripe grade of A and an optical uniformity Δn ≤5×10⁻⁶. -5 .

[0023] The aforementioned components enable the geometric waveguide glass material to simultaneously achieve high refractive index and low stray light, keeping the critical angle of total internal reflection within 36.5°. This provides a key condition for the design of optical systems with a large field of view (≥50°×40°). The smaller critical angle allows light to enter the waveguide interface at a larger angle, thereby expanding the effective field of view. Meanwhile, low dispersion and a suitable Abbe number ensure the consistency of light transmission at different wavelengths, avoiding color distortion at the edges of the image.

[0024] Example 1:

[0025] The following raw materials are weighed according to their mass percentages: zinc oxide: 20%, lanthanum oxide: 25%, tantalum pentoxide: 15%, niobium pentoxide: 10%, boron oxide: 15%, clarifying agent: 0.2%, and silicon dioxide: 24.8%. The purity of the above raw materials, including zinc oxide, lanthanum oxide, tantalum pentoxide, niobium pentoxide, boron oxide, and silicon dioxide, is ≥99.99%, and the total impurity content is ≤0.01%.

[0026] Preparation process:

[0027] (1) The oxide raw material uses zirconia beads with a diameter of 5 mm as the grinding medium. The ball mill speed is 300-400 r / min. The mixture is mixed for 2 hours. After mixing, the particle size of the raw material is ≤5 μm. Then it is sieved (through a 200 mesh sieve). After sieving, the raw material is placed in a vacuum drying oven at 120-150℃ and dried for 4-6 hours. The moisture content of the raw material is controlled to be ≤0.05%. After drying, it is cooled to room temperature and then transferred to a platinum crucible.

[0028] (2) Then place the raw material in a platinum crucible and melt it at 1600°C for 4 hours, stirring for 10 minutes every hour;

[0029] (3) Cool the raw material in the platinum crucible to 1450°C, add a clarifying agent, and purge with 0.8 MPa nitrogen gas to keep it warm and clarify for 1 hour;

[0030] (4) Pour the raw material in the platinum crucible into a graphite mold that is preheated to 500-520℃ and coated with a high-temperature resistant boron nitride release agent with a coating thickness of 5-10μm. After the mold is preheated, keep it at the temperature for 1-2 hours to avoid defects such as uneven thickness and surface cracks on the substrate, and form a 1.5mm thick substrate.

[0031] (5) Step annealing: The first stage is held at 500-520℃ for 2.5-3 hours (compared to the basic process, this embodiment raises the temperature of the first stage to above 500℃ and extends the holding time to more fully release the residual stress accumulated during the ultra-thin glass forming process), the second stage is held at 420-430℃ for 3.5-4 hours (the temperature of the second stage is adjusted to 420-430℃ to form a larger step temperature difference with the first stage, further suppressing the local enrichment of high field strength ions during the cooling process and optimizing optical uniformity), and then at 1.5℃ Cooling to room temperature at a rate of / min; After the above annealing treatment, the glass material's transition temperature Tg is 430-470℃, which is the annealing transition temperature of the glass. The ion exchange temperature of 420℃ is 10-50℃ lower than the lower limit of this temperature range. Furthermore, the 95:5 anhydrous potassium nitrate and sodium nitrate composite salt system used in this invention is a low-melting-point salt system. The molten salt has a mild thermal conductivity effect on the glass. Combined with precise temperature control treatment for 3-4 hours (molten salt temperature fluctuation ≤ ±2℃), stress relaxation can be effectively avoided, ensuring the stable formation of the compressive stress layer during the ion exchange process.

[0032] (5a) The annealed glass substrate is cut, ground and chemically mechanically polished to make the surface roughness Ra≤1nm;

[0033] (6) The formed glass substrate was placed in an anhydrous potassium nitrate and sodium nitrate composite salt system with a mass ratio of 95:5 at 430℃ for ion exchange treatment for 3 hours. The purity of potassium nitrate and sodium nitrate was ≥99.9%, forming a surface compressive stress layer. The transformation temperature Tg of the glass substrate was 430-470℃, which is the annealing transformation temperature of glass. The ion exchange temperature of 420℃ was 10-50℃ lower than the lower limit of this temperature range. With precise temperature control of molten salt temperature fluctuation ≤±2℃ and mild heat conduction of low molten salt system, no stress relaxation phenomenon occurred within the treatment time of 3-4 hours. The compressive stress layer remained intact after testing, which ensured the stable formation of the compressive stress layer during the ion exchange process and avoided stress relaxation.

[0034] Performance testing: n d =1.705, =36.5, visible light transmittance 93.2%, bubble grade A0 (GB / T 903-2019 "Colorless Optical Glass"), surface compressive stress 465MPa; after ion exchange, stress test shows compressive stress layer depth 52μm, no stress relaxation phenomenon, tensile strength 820MPa (tested according to GB / T 7962.6-2010 "Test Methods for Colorless Optical Glass Part 6: Tensile Strength" standard).

[0035] Example 2:

[0036] Raw materials were selected by weight (compared with Example 1): Zinc oxide: 18% (decreased by 2 percentage points); Lanthanum oxide: 27% (increased by 2 percentage points); Tantalum pentoxide: 17% (increased by 2 percentage points); Niobium pentoxide: 12% (increased by 2 percentage points); Boron oxide: 13% (decreased by 2 percentage points); Clarifying agent: 0.35% (increased by 0.15 percentage points); Silicon dioxide: 12.65% (decreased by 12.15 percentage points). The purity of the above raw materials of zinc oxide, lanthanum oxide, tantalum pentoxide, niobium pentoxide, boron oxide, and silicon dioxide were all ≥99.99%, and the total impurity content was ≤0.01%.

[0037] To adapt the preparation process parameters to the composition adjustments in this embodiment, the melting temperature was adjusted to 1600-1620℃, the melting time was extended to 4.5 hours, and the stirring speed was increased to 40-50 r / min. For the two-stage annealing process, the first stage holding temperature was adjusted to 500-520℃, and the holding time was extended to 2.5-3 hours; the second stage holding temperature was adjusted to 420-440℃, and the holding time was extended to 3.5-4 hours; the slow cooling rate was adjusted to 1℃ / min. The remaining process steps were the same as in Example 1. The above-mentioned adjustments to the annealing parameters aim to match the higher crystallization suppression requirements after the increased content of lanthanum oxide, tantalum pentoxide, and niobium pentoxide in this embodiment. By increasing the first-stage temperature and extending the two-stage holding time, the effects of thermal stress elimination and optical uniformity optimization are further enhanced. Under the above-mentioned adapted process:

[0038] Performance testing: Increasing the proportions of lanthanum oxide, tantalum pentoxide, and niobium pentoxide can further improve the refractive index of the glass (actual n). d =1.722, achieving the target of ≥1.72), while maintaining the dispersion coefficient through the synergistic effect of rare earth elements and reducing the proportion of silicon dioxide to reduce the influence of low refractive index components.

[0039] Mechanical strength enhancement: Increasing the niobium pentoxide content (enhancing network structure stability), combined with stress control through stepped annealing, can increase the surface compressive stress to 450-480MPa, thereby improving the glass's impact resistance (tested according to GB / T7962.6-2010 "Test Methods for Colorless Optical Glass Part 6: Tensile Strength" standard).

[0040] Increasing the clarifier ratio to 0.35%, combined with nitrogen protection, can further reduce bubble defects. At the same time, by adjusting the oxide ratio to reduce impurity absorption, the visible light transmittance can be increased to 94.5%.

[0041] Improved ion exchange effect: Reducing the ratio of boron oxide and silicon dioxide can increase the porosity of the glass network. Under the premise of maintaining an exchange time of 3 hours, the stress layer depth can be further increased to 58μm (≥55μm). In this embodiment, the glass Tg is 440-460℃. After 3 hours of treatment at an ion exchange temperature of 420℃, the molten salt temperature fluctuation is controlled within ±1℃. The test shows that the compressive stress layer has no relaxation and the surface compressive stress reaches 475MPa.

[0042] Specifically, the clarifying agent is a combination of antimony trioxide and ammonium chloride, with antimony trioxide accounting for 0.15-0.3% and ammonium chloride accounting for 0.05-0.1%, and the total mass percentage of antimony trioxide and ammonium chloride is 0.2-0.4%. Antimony trioxide decomposes at high temperatures to produce gas, which merges with tiny bubbles in the glass melt, causing the bubbles to rise and reducing bubble residue.

[0043] Furthermore, the geometric waveguide glass material has a thickness ≤1.5mm, a critical angle for total internal reflection ≤36.5°, and a stray light suppression rate ≥90% at the waveguide coupling outlet. Its surface is double-sided polished using chemical mechanical polishing (CMP) technology. The rough polishing stage uses 50nm colloidal silica abrasive, and the fine polishing stage uses 20nm colloidal silica abrasive, resulting in a surface roughness Ra ≤1nm after polishing. The surface of the geometric waveguide glass material is coated with an anti-reflection film and a semi-reflective and semi-transparent film system with a film thickness of 100-200nm, resulting in an overall transmittance ≥85% and a light leakage rate ≤10%. Through the optical interference of the film layer, light reflection loss is reduced, allowing ambient light (real scene) and virtual image light (display signal) to pass through the waveguide more efficiently, ensuring the naturalness of the superposition of virtual and real scenes. The film system balances "virtual image clarity" and "real scene transmittance," ensuring high brightness display of virtual information without affecting the user's observation of the real environment, thus realizing the core "virtual-real fusion" experience of AR technology.

[0044] A fabrication process for a high-refractive-index, low-stray-light geometric optical waveguide glass includes the following steps:

[0045] Step 1: Weigh the raw materials according to the formula, mix them evenly, place the mixed raw materials in a vacuum drying oven at 120-150℃ and dry for 4-6 hours, controlling the moisture content of the raw materials to be ≤0.05%. After drying, cool to room temperature and then place in a platinum crucible.

[0046] Step 2: Melt at 1580-1620℃ for 3-5 hours. Stir for the first time 1 hour after the start of melting, stirring 2-3 times at a speed of 30-50 r / min, each stirring lasting 10-15 minutes.

[0047] Step 3: Cool to 1450℃, add clarifying agent, and maintain the temperature for 1 hour for clarification; during the clarification process, high-purity anhydrous nitrogen gas is bubbled through the porous vent plug at the bottom of the platinum crucible, with the gas flow rate controlled at 0.5-1 L / min, and the nitrogen gas pressure inside the crucible is kept stable at 0.5-1.0 MPa throughout the process, with a nitrogen purity ≥99.99%;

[0048] Step 4: Pour the mixture into a graphite mold preheated to 500-520℃ with an inner wall coated with a high-temperature resistant boron nitride release agent (coating thickness 5-10μm). After preheating the mold, hold it at that temperature for 1-2 hours to ensure uniform temperature within the mold and prevent uneven glass substrate thickness and surface cracks caused by localized temperature differences. Then, perform a two-stage annealing process: the first stage is held at 500-520℃ for 2.5-3 hours to eliminate thermal stress; the second stage is held at 420-430℃ for 3.5-4 hours to optimize optical uniformity. After annealing, slowly cool the mixture to room temperature at a rate of 1-2℃ / min.

[0049] Step 5: Place the polished glass substrate in an anhydrous potassium nitrate and sodium nitrate composite salt system with a mass ratio of 95:5 at 430-450℃ for ion exchange treatment for 3-4 hours. The purity of potassium nitrate and sodium nitrate should be ≥99.9%. During the ion exchange process, the molten salt should be continuously stirred at a rate of 100-200 r / min, and the temperature fluctuation of the molten salt should be kept ≤±2℃ to form a surface compressive stress layer.

[0050] The thickness of the geometric waveguide glass material is ≤1.5mm, and the surface roughness Ra is ≤1nm after chemical mechanical polishing. The ion exchange treatment makes the surface compressive stress ≥450MPa, the compressive stress layer depth ≥50μm, and the tensile strength of the glass substrate ≥800MPa (tested according to GB / T 7962.6-2010 "Test Methods for Colorless Optical Glass Part 6: Tensile Strength" standard).

[0051] It should be noted that chemical strengthening presents unique challenges for ultrathin glass with a thickness ≤1.5mm: excessively long strengthening times can lead to stress relaxation, while insufficient strengthening time results in inadequate stress layer depth. This application utilizes a high-purity (≥99.9%) anhydrous potassium nitrate and sodium nitrate composite salt system with a mass ratio of 95:5 as the ion exchange molten salt. This effectively avoids interference from impurity ions in the exchange process. Combined with an ultra-smooth surface with a roughness Ra ≤1nm after chemical mechanical polishing, stress concentration points are reduced. Thus, a good balance is achieved between surface compressive stress ≥450MPa and compressive stress layer depth ≥50μm within a strengthening time of 3-4 hours, enabling the waveguide glass to maintain optical performance while possessing mechanical reliability suitable for engineering applications.

[0052] Working principle: In the preparation of geometric waveguide glass, oxide raw materials are first selected and ground and mixed in a ball mill for 2 hours to ensure a particle size ≤5μm and uniform composition. After drying and cooling, the mixture is placed in a platinum crucible and melted at 1580-1620℃ for 3-5 hours, stirring for 10 minutes every hour to promote component diffusion. After cooling to 1450℃, a clarifying agent is added, and high-purity anhydrous nitrogen gas at a pressure of 0.5-1.0MPa is introduced to suppress volatilization and accelerate bubble rise. The mixture is kept at this temperature for 1 hour for clarification. Then, the molten glass... The molten glass is poured into a graphite mold preheated to 500-520℃. After preheating, the mold is kept at that temperature for 1-2 hours to ensure uniform temperature on the inner wall of the mold and avoid uneven thickness and surface cracks in the glass substrate caused by local temperature differences. By controlling the cooling rate, a substrate with a thickness of 1.2-1.5mm is prepared. Then, a two-stage annealing process is performed to eliminate thermal stress and optimize the optical uniformity of the glass material. After annealing, the glass substrate is cut, ground, and chemically mechanically polished, and then subjected to ion exchange treatment to form a surface compressive stress layer.

[0053] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A geometric optical waveguide glass material with high refractive index and low stray light, characterized in that, Its composition, by mass percentage, includes: zinc oxide: 18-22%, lanthanum oxide: 23-27%, tantalum pentoxide: 13-17%, niobium pentoxide: 8-12%, boron oxide: 13-17%, clarifying agent: 0.2-0.4%, and the remainder being silicon dioxide; the purity of the raw materials of zinc oxide, lanthanum oxide, tantalum pentoxide, niobium pentoxide, boron oxide, and silicon dioxide is ≥99.99%, and the total impurity content is ≤0.01%; the refractive index n of the geometric waveguide glass is... d The Abbe number is 1.68-1.

72. The wavelength is 35-38, with a transmittance of ≥92% in the visible light band and a stray light suppression rate of ≥90%. The geometric waveguide glass material undergoes a two-stage annealing process, achieving an internal stripe grade of A and an optical uniformity Δn ≤ 5 × 10⁻⁶. -5 The two-stage annealing process includes: a first stage of holding at 500-520℃ for 2.5-3 hours, and a second stage of holding at 420-430℃ for 3.5-4 hours.

2. The high refractive index, low stray light geometric waveguide glass material according to claim 1, characterized in that, The clarifying agent is a combination of antimony trioxide and ammonium chloride, wherein antimony trioxide accounts for 0.15-0.3%, ammonium chloride accounts for 0.05-0.1%, and the total mass percentage of antimony trioxide and ammonium chloride is 0.2-0.4%.

3. The high refractive index, low stray light geometric waveguide glass material according to claim 2, characterized in that, Its thickness is ≤1.5mm and the critical angle of total internal reflection is ≤36.5°. Its surface is polished on both sides by chemical mechanical polishing process. The rough polishing stage uses 50nm colloidal silica abrasive and the fine polishing stage uses 20nm colloidal silica abrasive. The surface roughness Ra after polishing is ≤1nm.

4. The high refractive index, low stray light geometric waveguide glass material according to claim 1, characterized in that, Its surface is coated with a SiO2 / TiO2 multilayer antireflection film and a Nb2O5 / SiO2 semi-reflective and semi-permeable film stack, with a film thickness of 100-200nm, so that the overall transmittance is ≥85% and the light leakage rate is ≤10%.

5. A process for fabricating a high-refractive-index, low-stray-light geometric waveguide glass, applied to a high-refractive-index, low-stray-light geometric waveguide glass material according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Weigh the raw materials according to the formula, mix them evenly, and place them in a platinum crucible; Step 2: Melt at 1580-1620℃ for 3-5 hours, with a stirring interval of 1 hour. The first stirring should be carried out 1 hour after the start of melting, and the stirring should be carried out 2-3 times at a speed of 30-50 r / min, each stirring for 10-15 minutes. Step 3: Cool down to 1450℃, add clarifying agent, and keep warm for 1 hour to clarify; Step 4: Pour the mixture into a graphite mold preheated to 500-520℃ with an inner wall coated with a high-temperature resistant boron nitride release agent with a coating thickness of 5-10μm. After preheating the mold, hold it at that temperature for 1-2 hours, followed by a two-stage annealing process: the first stage is held at 500-520℃ for 2.5-3 hours, and the second stage is held at 420-430℃ for 3.5-4 hours. After annealing, slowly cool the mixture to room temperature at a rate of 1-2℃ / min. Step 5: Cut, grind and chemically mechanically polish the annealed glass substrate to make the surface roughness Ra≤1nm. Place the polished glass substrate in an anhydrous potassium nitrate and sodium nitrate composite salt system with a mass ratio of 95:5 at 430-450℃ for ion exchange treatment for 3-4 hours. The purity of potassium nitrate and sodium nitrate is ≥99.9%. During the ion exchange process, the molten salt is continuously stirred at a rate of 100-200r / min and the temperature fluctuation of the molten salt is kept ≤±2℃ to form a surface compressive stress layer. The ion exchange treatment results in a surface compressive stress ≥450MPa, a compressive stress layer depth ≥50μm, and a glass substrate tensile strength ≥800MPa.

6. The fabrication process for a high-refractive-index, low-stray-light geometric waveguide glass according to claim 5, characterized in that, In step three, the clarification process involves introducing high-purity anhydrous nitrogen gas through a porous vent plug at the bottom of the platinum crucible in a bubbling manner. The gas flow rate is controlled at 0.5-1 L / min, and the nitrogen gas pressure inside the crucible is kept stable at 0.5-1.0 MPa throughout the process, with a nitrogen purity ≥99.99%.

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