A black lidar window glass

Abstract

The application discloses a kind of black laser radar window glass, belong to glass technical field. By glass colorant, cadmium oxide and dry base glass batch with mass ratio 0.01-2:0-10:100 are prepared. The window glass prepared by the application is borosilicate glass, which has high transmittance in the near-infrared region. The glass colorant is a mixture of cadmium selenide and cadmium telluride in a weight percentage of 0-80%:30-90%, which can make the glass have very low transmittance in the visible light region. The melting is carried out under negative pressure, which reduces the volatilization and oxidation of the colorant and improves the melting and fining quality of the window glass. The addition of cadmium oxide ensures the melting quality and optical performance of the glass. Therefore, the window glass prepared by the application has low transmittance in the visible light region and high transmittance in the near-infrared region, is black, environmentally friendly, has excellent melting quality and optical performance, and has important application value in the field of laser radar window glass technology.

Description

Technical Field

[0001] This invention belongs to the field of glass technology, specifically relating to a black laser radar window glass. Background Technology

[0002] LiDAR (Light Detection and Ranging) is a radar system that uses laser beams to detect the position, velocity, and other characteristics of targets. It is currently widely used in aerospace, defense, automotive radar, energy, and many other fields. Driven by the rapid development of autonomous driving technology in the 21st century, the development of LiDAR equipment has attracted much attention. The optical glass in LiDAR components includes lenses, mirrors, narrowband filters, and window glass. Among them, the LiDAR laser flat window is a parallel planar plate that protects electronic sensors or detectors. For security, this window glass must have extremely low transmittance in the visible light range and high transmittance in the near-infrared region, appearing black. Commonly used optical windows are made of materials such as quartz glass or polycarbonate. However, these materials have high transmittance in the visible light range, failing to effectively protect internal components, and some also have poor mechanical properties. In view of these shortcomings, we aim to develop a material with extremely low transmittance in the visible light range, high transmittance in the near-infrared region, and good mechanical properties as a window material for LiDAR.

[0003] Borosilicate glass possesses excellent thermal stability, chemical stability, mechanical properties, processability, and optical properties. Its superior properties make it suitable for use as a window glass in lidar systems across numerous fields. However, borosilicate glass exhibits high transmittance in both the visible and near-infrared regions. Therefore, there is an urgent need to find a compound that can influence the optical absorption of borosilicate glass while maintaining its other excellent properties, allowing it to have extremely low transmittance in the visible region without compromising its high transmittance in the near-infrared region.

[0004] Cadmium selenide and cadmium telluride, both belonging to group II-VI compounds, possess semiconducting properties. They have relatively high lattice constants, narrow band gaps, and significant intrinsic absorption in the near-infrared region. Cadmium selenide is used as a colorant in borosilicate glass to develop a lidar window glass. This glass exhibits strong absorption in the visible light region and high transmittance in the near-infrared region. However, the preparation process of borosilicate glass involves high melting temperatures, high viscosity, and long refining times. Furthermore, cadmium telluride tends to exist in a free state within the glass during dissolution, and this free tellurium exhibits strong absorption in the near-infrared region. Therefore, these issues need to be addressed to meet the higher demands of lidar window glass technology. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a black laser radar window glass.

[0006] The objective of this invention can be achieved through the following technical solutions: A black lidar window glass is prepared by the following steps: S1. Mix the glass colorant with cadmium oxide and dry glass batching material, pour the mixture into a crucible, and then place it in a high-temperature furnace. Heat the furnace to 1500-1700℃ to melt and clarify the mixture, and obtain molten glass. S2. Pour the molten glass from step S1 into a mold for shaping; place the shaped glass in an annealing furnace at 700-850℃ for annealing, and then cut and polish it to obtain black laser radar window glass.

[0007] Furthermore, the mass ratio of the glass colorant, cadmium oxide, and dry-based glass batch is 0.01-2:0-10:100.

[0008] Furthermore, the glass colorant is obtained by mixing cadmium selenide and cadmium telluride in a weight percentage of 0-80%:30-90%.

[0009] Furthermore, the dry-based glass batch material comprises the following components by mass percentage: SiO2: 70-88%, B2O3: 4-12%, Al2O3: 1-4%, Na2O: 1-4%, K2O: 0.05-0.2%, NaCl: 1-5%, ZnO: 0-5%.

[0010] Furthermore, all the dry-based glass batch materials are chemically pure, wherein the raw material for B2O3 is H3BO3, the raw material for K2O is K2CO3, and the raw material for Na2O is NaNO3.

[0011] Furthermore, the SiO2 in the dry-based glass compound is silica aerogel.

[0012] Furthermore, the crucible is a high-purity quartz crucible.

[0013] Furthermore, the high-temperature furnace has adjustable internal gas pressure. During clarification, the working gas pressure in the furnace is 0.3-0.7 standard atmospheres, and the melting time is 1-3 hours.

[0014] Furthermore, the annealing furnace is a medium-low temperature muffle furnace, and the annealing time is 0.5-2 hours.

[0015] Borosilicate glass exhibits high transmittance in the visible and near-infrared regions. The glass colorant of this invention is arsenic- and antimony-free, making it environmentally friendly and easy to use. CdSe and CdTe have distinct absorption limits between the visible and near-infrared regions. This invention utilizes the intrinsic absorption of CdSe and CdTe, adding them as colorants in a specific ratio to the borosilicate glass batch for melting, resulting in CdSe-CdTe-containing borosilicate glass. The light absorption is due to photoexcited anions (O₂O₃O₄⁻). 2- Se 2- TeTe 2- This is due to the valence electrons of Se being excited to the excited state. 2- Te 2- Electrophilic potential < O 2- Therefore, relatively low energy is required to excite it, causing its absorption limit to enter the visible light region, thus giving the glass extremely low transmittance in the visible light region and achieving coloration. The absorption limit of CdSe-CdTe in glass is generally between 710-840 nm, and the position of the absorption limit mainly depends on the ratio of CdSe and CdTe. The reaction during glass melting and heat treatment is complex. Compared with Se, Te exhibits stronger metallic properties, with a higher boiling point and lower vapor pressure. CdTe easily exists in a free state in the glass during dissolution. Free Te has strong absorption in the near-infrared region. The higher the CdTe content, the more free Te exists, and the stronger the absorption. To address this, this invention adds CdO to the melting composition. When CdO is introduced into the glass, Cd ions can combine with O ions and reside outside the glass network. During heat treatment, the Cd outside the glass network may combine with free Te to form CdTe, gradually reducing and eliminating free Te. This greatly improves the near-infrared transmittance of the glass after introducing CdO. Meanwhile, high borosilicate glass has a high viscosity and is difficult to defoam, so the melting and clarification time is long. However, the long-term high temperature state will also aggravate the generation of free Te. In order to shorten the clarification time and obtain high-quality glass, this invention adopts a depressurization clarification method to accelerate the defoaming process of molten glass, improve the clarification quality of glass and reduce the melting and clarification time, so as to achieve better optical performance.

[0016] The beneficial effects of this invention are: 1. The window glass obtained by this invention is borosilicate glass, which has high transmittance in the near-infrared region; 2. Glass colorants contain cadmium selenide and cadmium telluride, which enable the glass to have extremely low transmittance in the visible light region, thus giving it a black color. 3. High-temperature melting under negative pressure reduces the volatilization and oxidation of colorants during the entire melting process, improves the melting and clarification quality of black lidar window glass, and is environmentally friendly; 4. The addition of cadmium oxide ensures the melting quality and optical properties of the glass; Therefore, the window glass produced by this invention has low transmittance in the visible light region, high transmittance in the near-infrared region, is black, and is environmentally friendly. It also has excellent melting quality and optical performance, and has important application value in the field of lidar window glass technology. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1 The following are transmittance curves for Examples 1-6 of the present invention.

[0019] Figure 2 The transmittance curves are for embodiments 7-12 of the present invention. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] In the embodiments of the present invention, the cadmium telluride and cadmium selenide raw materials are commercially available CdTe and CdSe compounds prepared by thermal synthesis or deposition method.

[0022] A black lidar window glass is prepared by the following steps: S1. Mix the glass colorant with cadmium oxide and dry glass batching material, pour it into a high-purity quartz crucible, and then place it in a high-temperature furnace. Heat the furnace to 1500-1700℃ to melt and clarify the glass to obtain molten glass. S2. Pour the molten glass from step S1 into a mold for shaping; place the shaped glass in an annealing furnace at 700-850℃ for annealing, and then cut and polish it to obtain black laser radar window glass. The mass ratio of the glass colorant, cadmium oxide, and dry-based glass batch is 0.01-2:0-10:100; The glass colorant is obtained by mixing cadmium selenide and cadmium telluride in a weight percentage of 0-80%:30-90%; The dry-based glass batch material comprises the following components by mass percentage: SiO2: 70-88%, B2O3: 4-12%, Al2O3: 1-4%, Na2O: 1-4%, K2O: 0.05-0.2%, NaCl: 1-5%, ZnO: 0-5%; all dry-based glass batch materials are chemically pure, wherein the raw material for B2O3 is H3BO3, the raw material for K2O is K2CO3, and the raw material for Na2O is NaNO3; SiO2 is silica aerogel.

[0023] Following the above steps and controlling the amount and conditions of the raw materials, Examples 1-12 were obtained, and their performance was measured. The transmittance of Examples 1-12 at wavelengths greater than 600 nm was plotted, as shown below. Figure 1 and Figure 2 Then draw tables, namely Table 1 and Table 2; Table 1

[0024] Table 2

[0025] As shown in Table 1, in Examples 1-3, the ratio of CdSe to CdTe and the introduction of CdO all affect the transmittance of the glass samples in the visible and near-infrared regions. With the increase of CdTe content, the absorption of visible and near-infrared light by the glass gradually increases. The light absorption of the glass is basically the superposition of the light absorption of the CdSe-containing glass and the CdTe-containing glass, and neither exhibits the intrinsic absorption that should be present in the CdSe-CdTe solid solution. In Examples 4-6, as the CdO content increases, the near-infrared transmittance of the glass increases rapidly, while the transmittance in the visible light region decreases sharply. However, after increasing to a certain extent, the absorption in the visible light region remains unchanged, while the transmittance in the near-infrared region decreases. The absorption limit is located between 710 nm and 840 nm, and the position of the absorption limit depends on the ratio of CdSe to CdTe. Figure 1 The ratio of CdSe to CdTe can be clearly seen, which affects the transmittance.

[0026] As can be seen from Table 2, in Examples 7-9, as the pressure in the high-temperature furnace decreases, the time for debubbling the molten glass is shortened, which reduces the probability of CdTe generating free Te due to prolonged high temperature, and is more conducive to the transmission of light waves in the near-infrared region. In Examples 10-12, CdSe-CdTe solid solution microcrystals gradually precipitate within the glass during heat treatment. With increasing annealing temperature and time, the relative amount of CdTe within the solid solution increases, leading to a gradual increase in the lattice constant and a narrowing of the band gap. This shifts the light absorption limit towards longer wavelengths, affecting both the visible and near-infrared regions to varying degrees. Figure 2 It can be clearly seen that by controlling the ratio of CdSe and CdTe and adding an appropriate amount of CdO, the transmittance in the infrared region is better.

[0027] As shown in the two tables above, in the embodiments of the present invention, when CdSe, CdTe, and CdO in amounts greater than or equal to 4g are added, the average transmittance T < 5% in the visible light band (including but not limited to 380-780nm); and the transmittance T ≥ 85% in the near-infrared band (including but not limited to 905nm and 1550nm). The number of visible bubbles (>0.1mm) per square meter in the resulting black lidar window glass sample is no more than 1. Therefore, the window glass prepared by the present invention has low transmittance in the visible light region, high transmittance in the near-infrared region, is black, and is environmentally friendly. It also has excellent melting quality and optical performance, and has important application value in the field of lidar window glass technology.

[0028] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," 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.

[0029] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A black lidar window glass, characterized in that, It is prepared through the following steps: S1. Mix the glass colorant with cadmium oxide and dry glass batching material, pour the mixture into a crucible, and then place it in a high-temperature furnace. Heat the furnace to 1500-1700℃ to melt and clarify the mixture, and obtain molten glass. S2. Pour the molten glass from step S1 into a mold for shaping; place the shaped glass in an annealing furnace at 700-850℃ for annealing, and then cut and polish it to obtain black laser radar window glass. The mass ratio of the glass colorant, cadmium oxide, and dry-based glass batch is 0.01-2:4-10:100; the glass colorant is obtained by mixing cadmium selenide and cadmium telluride in a weight ratio of 1:2; the dry-based glass batch comprises the following components by mass percentage: SiO2: 70-88%, B2O3: 4-12%, Al2O3: 1-4%, Na2O: 1-4%, K2O: 0.05-0.2%, NaCl: 1-5%, ZnO: 0-5%. The high-temperature furnace has adjustable internal gas pressure. During clarification, the working gas pressure in the furnace is 0.3-0.7 standard atmospheres, and the melting time is 1-3 hours.

2. The black lidar window glass according to claim 1, characterized in that, All dry-based glass batches are chemically pure, with B2O3 made from H3BO3, K2O from K2CO3, and Na2O from NaNO3.

3. The black lidar window glass according to claim 1, characterized in that, The SiO2 in the dry glass batch is silica aerogel.

4. The black lidar window glass according to claim 1, characterized in that, The crucible is a high-purity quartz crucible.

5. The black lidar window glass according to claim 1, characterized in that, The annealing furnace is a medium-low temperature muffle furnace, and the annealing time is 0.5-2 hours.

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