High-temperature processing system for improving refractive index uniformity of monocrystalline silicon lens

Abstract

The invention discloses a high-temperature processing system for improving the refractive index uniformity of a monocrystalline silicon lens, and relates to the field of precision optical manufacturing and material science, and the high-temperature processing system comprises the steps: collecting the geometrical shape, material characteristics and historical data of the monocrystalline silicon lens, collecting the real-time temperature data of the monocrystalline silicon lens at the same time, and carrying out the preprocessing of all data, and based on the preprocessed real-time temperature data and historical data of the monocrystalline silicon lens, establishing a heat distribution prediction model, outputting a preliminary heat distribution prediction result, controlling a multi-zone heater in a heating high-temperature processing cavity according to the heat distribution prediction result, and injecting inert gas into the high-temperature processing cavity, the temperature control and environment configuration of the monocrystalline silicon lens are completed, the target refractive index of the target monocrystalline silicon lens is set based on design requirements and historical data, a possible overheating or supercooling area is accurately predicted according to actual conditions, an optimized heating power distribution basis is provided, local thermal stress concentration is avoided, and the reliability of the monocrystalline silicon lens is improved. And the refractive index uniformity of the lens is obviously improved.

Description

Technical Field

[0001] The invention relates to the fields of precision optical manufacturing and material science, and in particular to a high temperature processing system for improving the uniformity of the refractive index of a single crystal silicon lens. Background Art

[0002] The application of single crystal silicon materials as optical components, especially in high-precision optical lenses, has received extensive attention in recent years. Single crystal silicon has become an ideal material for lenses in high-precision optical systems due to its excellent mechanical stability, thermal properties and light transmittance. However, the optical properties of single crystal silicon lenses, especially the uniformity of refractive index, directly affect the imaging quality of the optical system and the transmission efficiency of the light beam.

[0003] The shortcomings of existing high-temperature processing systems in controlling refractive index uniformity are mainly due to the limited ability to accurately control the temperature field and the lack of detailed management of the temperature response of different parts of the single-crystal silicon lens. In particular, in traditional heating systems, the target value is usually set only based on the overall temperature of the lens, while ignoring the different responses of different areas to heating, resulting in local overheating or overcooling, resulting in thermal stress concentration, and thus affecting the refractive index uniformity of the lens. Summary of the invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a high temperature processing system for improving the uniformity of the refractive index of a single crystal silicon lens to solve the problems of insufficient uniformity of the refractive index and inaccurate temperature field control during the high temperature processing of the single crystal silicon lens.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a high temperature processing system for improving the uniformity of the refractive index of a single crystal silicon lens, which includes a data acquisition and preprocessing module, which collects the geometric shape, material properties and historical data of the single crystal silicon lens, and collects the real-time temperature data of the single crystal silicon lens, and preprocesses all the data;

[0008] The thermal distribution prediction model generation module establishes a thermal distribution prediction model based on the pre-processed real-time temperature data and historical data of the single-crystal silicon lens and outputs preliminary thermal distribution prediction results;

[0009] The multi-zone heating control module controls the multi-zone heaters in the high-temperature processing chamber according to the heat distribution prediction results, and injects inert gas into the high-temperature processing chamber to complete the temperature control and environmental configuration of the single crystal silicon lens;

[0010] A target refractive index setting module is used to set the target refractive index of the target single crystal silicon lens based on design requirements and historical data;

[0011] The optical feedback module monitors the refractive index of the lens surface in real time through a laser interferometer, compares it with the target refractive index of the target single crystal silicon lens, and outputs the comparison result;

[0012] The refractive index control feedback module feeds back the comparison results to the thermal distribution prediction model, and the thermal distribution prediction model further optimizes the thermal power distribution of the multi-zone heater according to the refractive index deviation;

[0013] The cooling control module reduces the power of the multi-zone heater after the heating process is completed, the dynamic atmosphere control module switches to a vacuum environment, and the optical feedback module continues to collect and monitor the changes in the refractive index distribution during the cooling process;

[0014] The task report generation and storage module generates a task report based on the task and uploads the report to the system.

[0015] As a preferred solution of the high temperature treatment system for improving the refractive index uniformity of the single crystal silicon lens of the present invention, the geometric shape, material properties and historical data of the single crystal silicon lens are collected, the real-time temperature data of the single crystal silicon lens is collected, and all the data are pre-processed, specifically including the following steps:

[0016] The historical data refers to the historical temperature distribution data, cooling rate, temperature drop data, refractive index change data, heating power and heat source distribution of single crystal silicon lenses with similar geometry and material properties to the current single crystal silicon lens;

[0017] All collected information is cleaned, standardized and normalized.

[0018] As a preferred solution of the high temperature treatment system for improving the refractive index uniformity of the single crystal silicon lens of the present invention, a thermal distribution prediction model is established based on the real-time temperature data and historical data of the single crystal silicon lens after pre-processing, and a preliminary thermal distribution prediction result is output, which specifically includes the following steps:

[0019] Extract temperature features from historical data to form historical temperature features;

[0020] Introducing an adaptive time decay factor to dynamically adjust the decay factor based on the similarity between real-time data and historical data;

[0021] The real-time temperature data is calculated through the heat conduction equation and thermal stress field to predict the temperature change and stress distribution in different areas of the single crystal silicon lens during high temperature treatment. The expression is:

[0022]

[0023] Where f(T) represents the calculated values ​​of thermal conduction effect and thermal stress effect, κ represents the thermal diffusion coefficient, represents the rate of change of temperature with spatial coordinates, Q represents the internal heat source term, ρ represents the density of the material, c p represents the specific heat capacity of the material, E represents the elastic modulus of the material, α T Indicates the ratio of the length of the material to the temperature change, T represents the current temperature, T0 represents the initial temperature of the material when it is not heated, δ ij represents the diagonal component in the selected stress tensor;

[0024] Perform multi-scale Fourier transform on historical temperature characteristics to extract periodic information at different scales;

[0025] The calculation results of temperature changes and stress distribution in different regions of the single-crystal silicon lens during high-temperature treatment are combined with the periodic information at different scales in the historical temperature characteristics to establish a thermal distribution prediction model.

[0026] Using the thermal distribution prediction model, and based on the real-time temperature data and historical temperature characteristics of the single crystal silicon lens, a preliminary thermal distribution prediction result is output, and its expression is:

[0027]

[0028] Among them, T pred (x, y, z, t) represents the predicted temperature distribution of the single crystal silicon lens, α h represents the weight of the hth historical temperature feature, H represents the number of historical temperature features, T h (x, y, z, t) represents the historical temperature characteristics, Ω i represents the area of ​​the single crystal silicon lens, and f(T) represents the values ​​of the thermal conduction effect and the thermal stress effect.

[0029] As a preferred solution of the high temperature treatment system for improving the refractive index uniformity of the single crystal silicon lens of the present invention, the multi-zone heater in the high temperature treatment chamber is adjusted according to the heat distribution prediction result, and an inert gas is injected into the high temperature treatment chamber to complete the temperature control and environmental configuration of the single crystal silicon lens, which specifically includes the following steps:

[0030] Determining a target temperature of each heating zone based on the predicted temperature distribution of the single crystal silicon lens;

[0031] Using a feedback control algorithm, the power output of the heating zone is adjusted in real time, so that the temperature of the heater zone gradually approaches the predicted temperature distribution of the single crystal silicon lens output by the prediction model;

[0032] At the same time, according to the size of the high-temperature processing chamber, the material processing requirements and the predicted temperature distribution, high-purity inert gas is selected to be injected into the chamber;

[0033] When the high temperature processing operation of the single crystal silicon lens enters a stable stage, the injection rate of the gas is adjusted by a flow controller;

[0034] While the inert gas is continuously injected, the gas in the cavity is continuously discharged;

[0035] The injected inert gas is monitored in real time, and the injection rate of the inert gas is dynamically adjusted according to the monitored inert gas data to complete the environmental configuration.

[0036] As a preferred solution of the high temperature processing system for improving the uniformity of the refractive index of a single crystal silicon lens according to the present invention, the target refractive index of the single crystal silicon lens is set based on the design requirements and historical data, specifically comprising the following steps:

[0037] Determine the optical performance requirements, mechanical stress and stress birefringence according to the actual application scenarios of single crystal silicon lenses, and obtain the design requirements of single crystal silicon lenses;

[0038] The refractive index data of single crystal silicon is extracted from historical data, and the mean value, standard deviation and extreme value range of the refractive index are extracted through statistical analysis. These data are then combined with the design requirements of the single crystal silicon lens to generate the target refractive index of the single crystal silicon lens.

[0039] As a preferred solution of the high temperature treatment system for improving the uniformity of the refractive index of a single crystal silicon lens according to the present invention, the refractive index of the single crystal silicon lens is monitored in real time by a laser interferometer, and compared with the target refractive index of the target single crystal silicon lens, and the comparison result is output, which specifically includes the following steps:

[0040] A laser interferometer uses a high-stability laser source to pass through a single-crystal silicon lens to obtain real-time interference fringe data, and the refractive index distribution of the single-crystal silicon lens is calculated using a fast Fourier transform algorithm;

[0041] The calculated refractive index of the single crystal silicon lens is compared with the target refractive index of the single crystal silicon lens and the comparison result is output.

[0042] As a preferred solution of the high temperature processing system for improving the refractive index uniformity of the single crystal silicon lens of the present invention, wherein: the comparison result is fed back to the thermal distribution prediction model, and the thermal distribution prediction model further optimizes the thermal power distribution of the multi-zone heater according to the refractive index deviation, specifically including the following steps:

[0043] Combining the refractive index comparison results with the predicted temperature distribution of the single crystal silicon lens, the area where the temperature distribution has a large error is output;

[0044] The model corrects the temperature distribution of the zone and adjusts the thermal power distribution of the multi-zone heater through the error back propagation algorithm.

[0045] As a preferred solution of the high temperature treatment system for improving the uniformity of the refractive index of a single crystal silicon lens according to the present invention, wherein: after the heating treatment is completed, the power of the multi-zone heater is reduced and switched to a vacuum environment, and the laser interferometer continues to collect and monitor the change of the refractive index distribution during the cooling process, specifically comprising the following steps:

[0046] When the heating process is completed, the power of the multi-zone heater is gradually reduced to cool the lens material, and the gas in the heating chamber is gradually pumped out to establish a low-pressure vacuum environment;

[0047] The laser interferometer continuously collects the refractive index distribution of the lens, compares this data with the target refractive index, and makes dynamic adjustments based on real-time data.

[0048] As a preferred solution of the high temperature treatment system for improving the uniformity of the refractive index of a single crystal silicon lens according to the present invention, wherein: generating a task report according to this task and uploading the report to the system specifically includes the following steps:

[0049] Record all data of the heating task, operating procedures, instructions issued by all modules during the task, and response results and upload them to the system for technical personnel to analyze and optimize.

[0050] The beneficial effects of the present invention are as follows: a thermal distribution prediction model is established based on the real-time temperature data and historical data of the pre-processed single crystal silicon lens through a thermal distribution prediction model generation module, and a preliminary thermal distribution prediction result is output. Through this module, the system can predict the temperature change and thermal stress distribution of the lens during high temperature treatment. The core of this module is to introduce the heat conduction equation and thermal stress field calculation, combined with an adaptive time decay factor, to dynamically adjust the temperature prediction model. This allows the system to accurately predict possible overheating or overcooling areas according to actual conditions, provide an optimized basis for heating power distribution, avoid local thermal stress concentration, and thus significantly improve the refractive index uniformity of the lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0052] Figure 1 This is a flow chart of a high temperature processing system for improving the refractive index uniformity of a single crystal silicon lens in Example 1.

[0053] Figure 2 This is a flow chart of the prediction of the heat distribution prediction model in Example 1. DETAILED DESCRIPTION

[0054] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0055] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0056] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0057] Example 1, reference Figure 1 and Figure 2 , which is the first embodiment of the present invention, provides a high temperature processing system for improving the uniformity of the refractive index of a single crystal silicon lens, comprising the following steps:

[0058] S1. The geometric shape of the lens (such as diameter, thickness, curvature, etc.) determines the temperature gradient and stress distribution in different regions during heating and cooling.

[0059] S1.1. Material properties (such as density, thermal diffusion coefficient, specific heat capacity, elastic modulus, etc.) directly affect the thermal response, thermal expansion behavior and stress birefringence effect of the lens.

[0060] S1.2. Historical data not only includes the temperature distribution and cooling rate of lenses that have been processed in the past, but also covers the change in refractive index of these lenses during the heat treatment process, the use of heating power and the distribution of heat sources. These data provide a lot of reference information for establishing a thermal distribution prediction model.

[0061] S1.3. During high temperature treatment, it is very important to monitor the temperature changes of the lens in real time. The system can timely understand the actual temperature distribution of the current lens by collecting temperature data of each area of ​​the lens in real time. These real-time data provide basic support for the adaptive adjustment and real-time feedback of the model, ensuring that the temperature changes during the heating process meet expectations.

[0062] S1.4. In order to improve the refractive index uniformity of the current single crystal silicon lens, the system extracts the historical temperature distribution data, cooling rate, temperature drop data, refractive index change data, heating power and heat source distribution of the single crystal silicon lens with similar geometry and material properties to the current lens from the historical database.

[0063] S1.4.1. The temperature distribution data records the temperature distribution of the historical lens during heating and cooling, especially the temperature changes at different time points and different positions. This data can provide a reference for the temperature prediction of the current lens.

[0064] S1.4.2. The cooling rate directly affects the release speed of the internal stress of the lens. Too fast or too slow cooling will lead to uneven stress inside the lens, which will further affect the uniformity of the refractive index. The cooling data provides a reference for the cooling process of the current lens.

[0065] S1.4.3. The refractive index change data refers to the refractive index, which is one of the most important optical performance parameters of single-crystal silicon lenses. The historical data records the refractive index changes of different lenses during high-temperature treatment and cooling, which helps to predict the change law of the refractive index of the current lens at different temperatures.

[0066] S1.4.4, the heating power and heat source distribution refers to the record of the heating power and heat source distribution used in different areas during the heating process. By referring to the heating power distribution of the historical lens, the system can more reasonably allocate the multi-zone heating power of the current lens and reduce the risk of local overheating or overcooling.

[0067] Collect the geometric shape, material properties and historical data of the single crystal silicon lens, collect the real-time temperature data of the single crystal silicon lens, and pre-process all the data, including the following steps:

[0068] The historical data refers to the historical temperature distribution data, cooling rate, temperature drop data, refractive index change data, heating power and heat source distribution of a single crystal silicon lens with similar geometry and material properties to the current single crystal silicon lens.

[0069] Further explanation: By extracting historical data similar to the current lens geometry and material properties, the system can refer to the processing experience under similar conditions when predicting the temperature and refractive index changes of the current lens. This method effectively reduces the deviation of model prediction and provides the system with an experience-based optimization solution. The combination of temperature distribution, cooling rate, refractive index change and other data enables the system to more accurately control the temperature changes during heating and cooling, avoiding local stress concentration or refractive index out of control due to lack of experience.

[0070] S1.5. Data cleaning refers to removing noise, outliers and invalid data to ensure the accuracy and completeness of input data.

[0071] Standardization is the process of converting different types of data into a unified dimension (such as temperature, power, refractive index change, etc.

[0072] Standardization is the process of converting different types of data into a unified dimension (such as converting temperature, power, refractive index change and other data into the same unit scale) so that the model can reasonably compare and analyze different data.

[0073] All collected information is cleaned, standardized and normalized.

[0074] S2. By extracting temperature features from historical data to form a historical temperature feature library, it is possible to provide rich empirical data for the thermal treatment process of the current lens.

[0075] Temperature characteristics include multi-dimensional information, such as temperature distribution at different time periods and locations, cooling rate under certain conditions, evolution of temperature gradient, etc. These characteristics help predict the temperature change pattern of the current lens under similar conditions.

[0076] S2.1. During high temperature treatment, the reference value of historical data will gradually weaken over time. Therefore, an adaptive time decay factor α is introduced. h , which is used to dynamically adjust the influence of historical data. The size of the attenuation factor is related to the similarity between real-time data and historical data. If the real-time data is very similar to a certain period of historical data, then the weight of the historical temperature feature is higher; conversely, as the similarity decreases, the attenuation factor will reduce the weight, causing the historical data to gradually lose its influence.

[0077] S2.2. In order to predict the temperature change and stress distribution of single crystal silicon lens during high temperature treatment, the system introduces the heat conduction equation and thermal stress field calculation. The heat conduction equation describes the heat transfer process inside the material, while the thermal stress field describes the material stress caused by temperature change. Its expression is:

[0078]

[0079] Where f(T) represents the calculated value of thermal conduction effect and thermal stress effect, κ represents the thermal diffusion coefficient, which reflects the rate of heat diffusion in the material. It represents the rate of change of temperature with spatial coordinates, reflecting the temperature gradient in different regions. Q represents the internal heat source term, which refers to the heat generated inside the material. ρ represents the density of the material. c p represents the specific heat capacity of the material, E represents the elastic modulus of the material, which reflects the deformation ability of the material under stress, and α T Indicates the ratio of the length of the material to the change in temperature, which refers to the expansion or contraction ratio of the material as the temperature changes. T represents the current temperature, T0 represents the initial temperature of the material when it is not heated, and δ ij Represents the Kronecker symbol, which is used to select the diagonal components in the stress tensor.

[0080] Further explanation: The combination of heat conduction equations and thermal stress fields enables the system to accurately predict the temperature gradient and stress distribution inside the lens, avoiding local overheating or stress concentration. This helps ensure that the lens will not crack or suffer other structural damage during high-temperature processing, ultimately improving the optical performance of the lens (such as refractive index uniformity).

[0081] S2.3. Perform multi-scale Fourier transform on the historical temperature characteristics. Through multi-scale Fourier transform, the periodic information at different frequencies (or scales) is extracted, that is, the periodic law of temperature change in different time ranges or spatial ranges, and its expression is:

[0082]

[0083] in, Represents the result after the historical temperature characteristics are transformed, T h (x, y, z, t) represents the historical temperature characteristics, which means the temperature value at a specific location (x, y, z) over time t. x Indicates the change of temperature characteristics at different spatial scales, corresponding to the x-coordinate direction, k y Indicates the change of temperature characteristics at different spatial scales, corresponding to the y coordinate direction, k z It represents the change of temperature characteristics at different spatial scales, corresponding to the z coordinate direction, ω represents the time frequency, reflecting the periodicity at different time scales, and t represents time.

[0084] Frequency domain analysis is performed based on the results of historical temperature feature transformation, but the final thermal distribution prediction needs to be performed in the time-space domain. Therefore, in order to finally predict the temperature distribution in the time-space domain, the frequency information after Fourier transformation is converted back to the time-space domain through inverse Fourier transformation. The result after conversion is T h (x,y,z,t).

[0085] S2.4. After the calculation of real-time temperature data and the extraction of periodic information of historical temperature characteristics are completed, the two are combined to establish a thermal distribution prediction model. This model can comprehensively consider the real-time temperature changes and stress distribution of the current lens, and refer to the periodic information extracted at different scales in the historical data to predict the temperature distribution of the lens during high-temperature treatment.

[0086] It is further explained that by combining the physical calculation of real-time data with the periodic laws of historical data, a more comprehensive prediction model is established. This model can not only capture the instantaneous changes of the current lens, but also refer to the long-term laws in history, ensuring that the prediction results are both real-time and continuous, thereby improving the reliability of the prediction.

[0087] S2.5. Output the preliminary thermal distribution prediction result of the lens through the thermal distribution prediction model, and its expression is:

[0088]

[0089] Among them, T pred (x, y, z, t) represents the predicted temperature distribution of the single crystal silicon lens, α h represents the weight of the hth historical temperature feature, H represents the number of historical temperature features, T h (x, y, z, t) represents the historical temperature characteristics, Ω i represents the area of ​​the single crystal silicon lens, and f(T) represents the values ​​of the thermal conduction effect and the thermal stress effect.

[0090] S3. Based on the predicted temperature distribution of the single crystal silicon lens, a corresponding target temperature is set for each heating zone (ie, different areas of the heater on the lens surface or in the processing chamber space).

[0091] The target temperature of each heating zone is determined based on the temperature requirements of the lens in that area. For example, if a certain area of ​​the lens requires a higher temperature to achieve uniform heat treatment, a higher target temperature will be set for that heating zone; if the temperature of a certain area does not need to be too high, a lower target temperature will be set accordingly.

[0092] Further explanation: By setting different target temperatures for each heating zone, the lens can be finely controlled to ensure a more uniform temperature distribution of the lens. This precise control can reduce the temperature gradient generated by the lens during high temperature treatment, avoid lens deformation, cracks or stress concentration caused by local over-high or over-low temperatures, and thus improve the optical performance of the lens.

[0093] S3.1. Use feedback control algorithm to monitor the temperature of the heating zone in real time, compare it with the target temperature, calculate the deviation between the two, and dynamically adjust the power output of the heater according to this deviation.

[0094] Further explanation: Through the feedback control algorithm, the heating process can be optimized in real time, ensuring that the temperature distribution is consistent with the predicted model even when the external environment changes. This can effectively avoid overheating or overcooling, ensure that the temperature distribution of the lens is uniform and stable throughout the high-temperature treatment process, and improve the processing quality and consistency of the lens.

[0095] S3.2. In order to prevent the lens from chemically reacting with oxygen or other reactive gases in the air at high temperatures, the system needs to select and inject high-purity inert gas (such as argon or nitrogen) according to the specific conditions of the processing chamber. Inert gas will not chemically react with single crystal silicon or other materials and can provide a protective atmosphere for the lens.

[0096] S3.2.1. The specific gas selection depends on the size of the high temperature processing chamber, the processing requirements of the material, and the predicted temperature distribution.

[0097] The size of the high temperature processing chamber means that the larger the processing chamber, the more inert gas is required;

[0098] The processing requirements of the materials mentioned above are different. Different materials have different requirements for the atmosphere. Some materials may require nitrogen, while others may require argon.

[0099] Dependence on the predicted temperature distribution refers to appropriately adjusting the flow pattern and pressure of the gas according to the temperature requirements of different areas to ensure a uniform atmosphere in the entire cavity.

[0100] S3.3. In the initial stage of high temperature treatment, the temperature and gas flow rate are frequently controlled to ensure that the lens can be heated up smoothly and reach the required temperature. However, once the temperature and atmosphere have reached a stable state, it will enter the stable operation stage. At this time, the injection rate of the inert gas is adjusted by the flow controller to maintain a stable atmosphere in the chamber.

[0101] The flow controller can dynamically adjust the inert gas inflow rate according to parameters such as gas concentration, pressure, and temperature in the processing chamber to ensure that the gas flow is neither too large to cause waste nor too small to cause an unstable atmosphere.

[0102] S3.3.1. While the inert gas is being injected, the gas in the chamber is continuously exhausted. This prevents unnecessary accumulation and changes in the gas concentration, chemical composition or pressure in the chamber.

[0103] S3.4. Real-time monitoring of the flow rate, purity, composition and other data of the injected inert gas. If changes in the flow rate, purity or pressure of the gas are detected, or if they exceed the preset range, the injection rate of the inert gas will be dynamically adjusted through the automatic control mechanism.

[0104] For example, if it is found that the concentration of inert gas in the chamber begins to decrease, the gas injection rate will be increased to maintain a stable atmosphere in the chamber; if the gas flow is too large, the system will reduce the injection rate to avoid waste.

[0105] It is further explained that through real-time monitoring and dynamic adjustment, it is possible to ensure that the atmosphere in the chamber always meets the requirements of high-temperature treatment, thereby improving the safety and stability of the treatment process. At the same time, this dynamic adjustment mechanism can also effectively reduce the waste of inert gas, reduce production costs, and improve the degree of automation of the treatment process.

[0106] S4. When designing a single crystal silicon lens, a series of design requirements must be determined based on its specific needs in practical applications, including optical performance requirements, mechanical stress, and stress birefringence.

[0107] The optical performance requirements refer to refractive index, transmittance and dispersion.

[0108] The mechanical stress will affect the performance of the single crystal silicon lens at high temperature or during processing. The lens may be subjected to mechanical loads, thermal stress or other environmental stresses during use, so the structural strength of the lens needs to be considered during design to ensure that it can withstand these stresses without cracking or deformation.

[0109] Stress birefringence is the difference in refractive index caused by stress inside the material, which in turn causes polarization splitting of light when it passes through the material. The birefringence effect can affect the imaging quality and precision of the optical system. When designing, it is necessary to consider how to control and reduce stress birefringence to ensure that the lens can maintain high-precision optical performance in the optical path.

[0110] S4.1. Collect single crystal silicon refractive index data measured under different temperatures, pressures, wavelengths, and processing conditions. These data come from previous experiments, literature, and measurement records during the production process.

[0111] The refractive index statistics are obtained by calculating the average value, standard deviation and extreme value range of the refractive index of single crystal silicon in the historical data.

[0112] S4.2. Combine the historical single crystal silicon refractive index statistical data with the single crystal silicon design requirements to generate the final single crystal silicon lens target refractive index.

[0113] It is further explained that by combining historical refractive index data and the needs of actual application scenarios, a precise target refractive index can be designed for the single-crystal silicon lens to ensure that the lens can meet the accuracy requirements of the optical system in actual applications.

[0114] S5. When the laser beam passes through a single crystal silicon lens, the optical path difference in the lens causes the formation of interference fringes. The distribution of interference fringes is directly related to the change in the local refractive index in the lens. Since the refractive index distribution of a single crystal silicon lens may vary slightly in different regions, these differences will cause the phase of the interference fringes to change.

[0115] The change of refractive index in the lens will cause the propagation speed of light inside the lens to change, which in turn affects the density and shape of the laser interference fringes. By observing the change of interference fringes, relevant information about the refractive index distribution inside the lens can be obtained.

[0116] The laser interferometer continuously collects interference fringe images and converts them into digital signals. The system captures the changes of interference fringes through high-precision cameras or optical sensors to ensure the real-time and accuracy of data collection.

[0117] S5.1, Fourier transform can convert the spatial information of interference fringes into the frequency domain, revealing the frequency components of interference fringes. Through FFT, the system can quickly analyze the frequency distribution of interference fringes and extract the periodic changes of fringes.

[0118] After the FFT algorithm extracts the frequency information of the fringes, the system will combine the geometric parameters of the lens (such as thickness, curvature, etc.) and the optical path difference formula to calculate the refractive index of light when it propagates at various positions of the lens, which is the actual refractive index.

[0119] S5.2. The system compares the actual refractive index distribution map with the target refractive index and analyzes the size and distribution of the refractive index error. If the error is within the acceptable range, the system will display that the lens meets the design requirements; if the error exceeds the specified tolerance range, the system will mark the area with larger error for further adjustment or correction.

[0120] Further explanation: By using a laser interferometer and a high-stability laser source, the system can obtain the interference fringe data of the single-crystal silicon lens in real time, and calculate the refractive index distribution of the lens through the fast Fourier transform (FFT) algorithm. The actual refractive index is compared with the designed target refractive index, and a detailed difference analysis and feedback results are output. The whole process can help ensure that the refractive index of the single-crystal silicon lens meets the design requirements and improve the optical performance of the lens.

[0121] S6. Generate a temperature error distribution diagram to show the temperature deviation of each area of ​​the lens. Areas with large errors will be specially marked to show that the temperature of these areas is significantly different from the predicted distribution.

[0122] S6.1. Calculate the temperature error of each heating zone, that is, the difference between the predicted temperature and the actual temperature. This error is inferred from the refractive index deviation.

[0123] S6.2. Calculate the sensitivity of the temperature error of each heating zone to its heating power.

[0124] For example, the temperature error in an area may be mainly caused by improper power output of one or several heating zones. The system will calculate the adjustment amount of the power of these heating zones through the back propagation algorithm.

[0125] S6.3. Adjust the power output of each heating zone according to the size and direction of the error. The magnitude of the power adjustment is determined by the size of the error, and the direction of the adjustment is determined by the positive or negative of the error (i.e., if the temperature is too high, reduce the power, and if the temperature is too low, increase the power). The back propagation algorithm is an iterative process that continuously adjusts the power output of the heating zone until the temperature error is minimized and the convergence condition is reached.

[0126] S6.4. According to the results calculated by the back propagation algorithm, appropriate power is allocated to each heating zone so that the lens temperature distribution in each area is consistent with the target temperature distribution.

[0127] For example, if a low temperature is detected in a certain area of ​​the lens, the system will increase the heating power of this area and its related areas accordingly; if a high temperature is detected, the heating power will be reduced.

[0128] It is further explained that the back propagation algorithm can automatically adjust the heater power according to the temperature error, reduce manual intervention, and improve the automation of heating control. By accurately adjusting the power output of each heating zone, the accuracy of temperature distribution can be significantly improved, local overheating or overcooling can be prevented, thereby improving the optical performance of the lens.

[0129] S7. After the heating process is completed, all heaters will not be turned off immediately, but the power output of each heating zone will be gradually reduced. This is to allow the lens to cool slowly and avoid thermal stress caused by rapid temperature changes. The system gradually reduces the power of each heating zone according to the cooling curve or the predetermined cooling rate to ensure that the temperature of each area of ​​the lens drops synchronously and prevent the temperature of a local area from dropping too quickly and causing a temperature gradient.

[0130] It is further explained that by controlling the cooling rate, it is possible to ensure that the stress inside the lens material is evenly released, avoiding stress concentration or thermal shock, thereby ensuring the structural and optical integrity of the lens.

[0131] S7.1. As the lens cools, gradually extract the gas in the heating chamber to create a low-pressure or even near-vacuum environment. The gradual extraction of gas is to avoid sudden pressure changes affecting the structure or heat conduction of the lens.

[0132] It is further explained that while establishing the vacuum environment, the system monitors the pressure changes in the heating chamber to ensure that the gas is slowly extracted to avoid stress or pressure difference impact on the lens surface due to a sharp drop in gas pressure.

[0133] S7.2. During the gradual cooling of the lens, the laser interferometer will continue to work and collect the refractive index distribution data of the lens in real time;

[0134] Further, continuous data collection helps the system track the trend of refractive index changes in real time, ensuring that any anomalies are detected in time during the cooling process. Real-time monitoring can also help verify whether the lens is cooled as expected and whether the thermal stress inside the material is effectively released.

[0135] S7.3. If the actual refractive index of some areas deviates greatly from the target refractive index, the heater power and cooling rate will be dynamically adjusted based on real-time data.

[0136] S8, recording the temperature data, heating power data, refractive index data, air pressure data, heating and cooling time of this heating task;

[0137] Records task configuration parameters, manual operation records, heater power adjustment steps and cooling process operations

[0138] Record the instructions issued by the module, for example, the output power of heater A is set to 200W and the temperature starts to rise;

[0139] The response result of the module is recorded. For example, heater A receives the power adjustment instruction according to the instruction, and the output power increases from 0W to 200W. The actual adjustment time is 5 seconds.

[0140] Further explanation, by recording the instructions and response results issued by each module, technicians can verify whether the system is working as expected. If any abnormalities occur, they can be traced back to the specific instructions and responses to quickly find the root cause of the problem.

[0141] S8.1. After uploading all data, operation procedures, instructions and response results to the system, technicians can find the root cause of abnormal problems by analyzing the data and operation records in the task.

[0142] For example, if there is a large temperature fluctuation in a certain area, it can be traced back to whether the heater power responded in a timely manner.

[0143] It is further explained that by uploading and analyzing data, technicians can identify problems in production and optimize them, thereby continuously improving the heating and cooling processes, and improving production efficiency and product quality.

[0144] This embodiment also provides a computer device, which is suitable for a high-temperature processing system for improving the uniformity of the refractive index of a single-crystal silicon lens, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement a high-temperature processing system for improving the uniformity of the refractive index of a single-crystal silicon lens as proposed in the above embodiment.

[0145] The computer device may be a terminal, and the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a key, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0146] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, a high-temperature processing system for improving the uniformity of the refractive index of a single-crystal silicon lens as proposed in the above embodiment is implemented; the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as a static random access memory (Static Random Access Memory, referred to as SRAM), an electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, referred to as EEPROM), an erasable programmable read-only memory (Erasable Programmable Read Only Memory, referred to as EPROM), a programmable read-only memory (Programmable Red-Only Memory, referred to as PROM), a read-only memory (Read-Only Memory, referred to as ROM), a magnetic storage device, a flash memory, a magnetic disk or an optical disk.

[0147] In summary, the present invention establishes a thermal distribution prediction model based on the real-time temperature data and historical data of the pre-processed single crystal silicon lens through a thermal distribution prediction model generation module, and outputs a preliminary thermal distribution prediction result. Through this module, the system can predict the temperature change and thermal stress distribution of the lens during high temperature treatment. The core of this module is to introduce the heat conduction equation and thermal stress field calculation, combined with an adaptive time attenuation factor, to dynamically adjust the temperature prediction model. This allows the system to accurately predict possible overheating or overcooling areas according to actual conditions, provide an optimized basis for heating power distribution, avoid local thermal stress concentration, and thus significantly improve the refractive index uniformity of the lens.

[0148] Example 2, referring to Table 1, is the second example of the present invention. To further verify the technical solution of the present invention, experimental simulation data of a high temperature processing system for improving the uniformity of the refractive index of a single crystal silicon lens is provided.

[0149] This embodiment aims to verify the effectiveness of a high temperature processing system for improving the uniformity of the refractive index of a single crystal silicon lens, and to demonstrate the advantages of the system in controlling the uniformity of the refractive index by comparing experimental data with comparative technologies.

[0150] In the experiment, a single crystal silicon lens material with a diameter of 100 mm and a thickness of 5 mm was prepared. The experiment was divided into a comparative technology experiment group and an invention system experiment group. The experimental environment was a high-temperature processing chamber, in which four independent heating zones were arranged, and each zone had a separate heating controller to ensure uniform heating.

[0151] Data collection and preprocessing module: First, the geometry, material properties and historical data of the single crystal silicon lens are collected, and the real-time temperature data of the lens is collected. All data are cleaned, standardized and normalized to ensure the accuracy and consistency of the data.

[0152] Thermal distribution prediction model generation module: Based on the real-time collected temperature data and historical data, the system establishes a thermal distribution prediction model. The model uses the heat conduction equation and thermal stress field for calculation to predict the temperature change and stress distribution in different areas of the single crystal silicon lens during high temperature treatment. In order to ensure the accuracy of the prediction, an adaptive time attenuation factor is introduced to dynamically adjust the attenuation factor according to the similarity between real-time data and historical data.

[0153] Multi-zone heating control module: According to the heat distribution prediction results, different target temperatures are set for the four heating zones. Through the feedback control algorithm, the power output of each heating zone is adjusted in real time to ensure the uniformity of temperature distribution. During the experiment, high-purity argon gas was injected into the chamber to create an inert environment, and the gas injection rate was monitored and adjusted in real time.

[0154] Target refractive index setting module: Based on historical data and design requirements, the target refractive index is set to 3.42. The design requirements take into account factors such as optical performance, mechanical stress, and stress birefringence.

[0155] Optical feedback module and refractive index control feedback module: The laser interferometer monitors the refractive index of the lens surface in real time and compares it with the target refractive index. If the refractive index deviates from the target value, the system adjusts the power distribution of the heating area through feedback to further optimize the heat distribution.

[0156] Cooling control module: After the high temperature treatment is completed, the heater power is gradually reduced and switched to a vacuum environment. During the cooling process, the laser interferometer continues to monitor the refractive index change of the lens to ensure the uniformity of the refractive index during the cooling process.

[0157] Task report generation and storage module: After the experiment, the system generates a task report, records the instructions, responses and experimental data of each module, and uploads the report to the system for technical personnel to analyze and optimize.

[0158] The details are shown in Table 1 below:

[0159] Table 1 Comparison of single crystal silicon lens high temperature processing systems

[0160]

[0161] It can be clearly seen from the experimental data that the system of the present invention has significant advantages over the comparative technology in multiple important parameters. The specific analysis is as follows:

[0162] Refractive index uniformity deviation: In the comparison technology system, the refractive index uniformity deviation is 0.028, while the system of the present invention reduces the deviation to 0.003, a reduction of 89.29%. This significantly shows that the thermal distribution prediction model and feedback adjustment mechanism of the present invention can effectively optimize the thermal power distribution of each area of ​​the lens and avoid the problem of inconsistent refractive index caused by uneven heating. Refractive index uniformity is crucial for high-precision optical applications, and the great reduction in deviation makes the optical performance of the lens in the application more superior.

[0163] Cooling time: The cooling time of the comparative technical system is 115 minutes, while the system of the present invention only takes 82 minutes, which is a reduction of 28.70%. The shortened cooling time is due to the precise regulation of the cooling control module of the present invention, especially by gradually reducing the heater power and controlling the dynamic vacuum environment, making the cooling process more efficient. This not only improves production efficiency, but also avoids the problem of material stress accumulation caused by excessive cooling time.

[0164] Heating zone temperature fluctuation: The heating zone temperature fluctuation range controlled by the system of the present invention is ±2°C, which is 71.43% less than the ±7°C of the comparative technology. The reduction of temperature fluctuation directly improves the temperature uniformity of the lens during high temperature treatment and avoids local overheating or overcooling. This result shows that the multi-zone heating control module of the present invention can accurately adjust the power output of each heating zone to ensure a more uniform overall temperature distribution of the lens.

[0165] Vacuum stabilization time: In the comparison technology system, the time to reach the target vacuum stabilization is 42 minutes, while the system of the present invention shortens this time to 29 minutes, a reduction of 30.95%. This difference shows that the dynamic atmosphere control module of the system of the present invention achieves more efficient coordination and control in terms of inert gas injection and vacuum environment establishment, thereby shortening the vacuum stabilization time. This is of great significance for improving process efficiency and accelerating production rhythm.

[0166] Final value of refractive index: The final value of the refractive index of the comparison technology system is 3.39, while the system of the present invention reaches the preset target of 3.42. Although the numerical difference seems small, in precision optical applications, a refractive index increase of 0.03 is very critical. The precise control of the refractive index benefits from the coordinated work of the optical feedback module and the refractive index control feedback module of the system of the present invention. Through real-time monitoring and feedback, the refractive index of the lens surface is ensured to be closer to the design requirements.

[0167] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A high temperature processing system for improving the uniformity of the refractive index of a single crystal silicon lens, characterized in that: include, The data acquisition and preprocessing module collects the geometry, material properties and historical data of the single-crystal silicon lens, collects the real-time temperature data of the single-crystal silicon lens, and preprocesses all the data; The thermal distribution prediction model generation module establishes a thermal distribution prediction model based on the pre-processed real-time temperature data and historical data of the single-crystal silicon lens and outputs preliminary thermal distribution prediction results; The multi-zone heating control module adjusts the multi-zone heaters in the high-temperature processing chamber according to the heat distribution prediction results, and injects inert gas into the high-temperature processing chamber to complete the temperature control and environmental configuration of the single crystal silicon lens; A target refractive index setting module is used to set the target refractive index of the target single crystal silicon lens based on design requirements and historical data; The optical feedback module monitors the refractive index of the lens surface in real time through a laser interferometer, compares it with the target refractive index of the target single crystal silicon lens, and outputs the comparison result; The refractive index control feedback module feeds back the comparison results to the thermal distribution prediction model, and the thermal distribution prediction model further optimizes the thermal power distribution of the multi-zone heater according to the refractive index deviation; The cooling control module reduces the power of the multi-zone heater after the heating process is completed, the dynamic atmosphere control module switches to a vacuum environment, and the optical feedback module continues to collect and monitor the changes in the refractive index distribution during the cooling process; The task report generation and storage module generates a task report based on the task and uploads the report to the system.

2. The high temperature processing system for improving the refractive index uniformity of a single crystal silicon lens as claimed in claim 1, characterized in that: Collect the geometric shape, material properties and historical data of the single crystal silicon lens, collect the real-time temperature data of the single crystal silicon lens, and pre-process all the data, including the following steps: The historical data refers to the historical temperature distribution data, cooling rate, temperature drop data, refractive index change data, heating power and heat source distribution of single crystal silicon lenses with similar geometry and material properties to the current single crystal silicon lens; All collected information is cleaned, standardized and normalized.

3. The high temperature processing system for improving the refractive index uniformity of a single crystal silicon lens as claimed in claim 2, characterized in that: Based on the pre-processed real-time temperature data and historical data of the single crystal silicon lens, a thermal distribution prediction model is established to output preliminary thermal distribution prediction results, which specifically includes the following steps: Extract temperature features from historical data to form historical temperature features; Introducing an adaptive time decay factor to dynamically adjust the decay factor based on the similarity between real-time data and historical data; The real-time temperature data is calculated through the heat conduction equation and thermal stress field to predict the temperature change and stress distribution in different areas of the single crystal silicon lens during high temperature treatment. The expression is: Where f(T) represents the calculated values ​​of thermal conduction effect and thermal stress effect, κ represents the thermal diffusion coefficient, represents the rate of change of temperature with spatial coordinates, Q represents the internal heat source term, ρ represents the density of the material, c p represents the specific heat capacity of the material, E represents the elastic modulus of the material, α T Indicates the ratio of the length of the material to the temperature change, T represents the current temperature, T0 represents the initial temperature of the material when it is not heated, δ ij represents the diagonal component in the selected stress tensor; Perform multi-scale Fourier transform on historical temperature characteristics to extract periodic information at different scales; The calculation results of temperature changes and stress distribution in different regions of the single-crystal silicon lens during high-temperature treatment are combined with the periodic information at different scales in the historical temperature characteristics to establish a thermal distribution prediction model. Using the thermal distribution prediction model, and based on the real-time temperature data and historical temperature characteristics of the single crystal silicon lens, a preliminary thermal distribution prediction result is output, and its expression is: Among them, T pred (x, y, z, t) represents the predicted temperature distribution of the single crystal silicon lens, α h represents the weight of the hth historical temperature feature, H represents the number of historical temperature features, T h (x, y, z, t) represents the historical temperature characteristics, Ω i represents the area of ​​the single crystal silicon lens, and f(T) represents the values ​​of the thermal conduction effect and the thermal stress effect.

4. The high temperature processing system for improving the refractive index uniformity of a single crystal silicon lens as claimed in claim 3, characterized in that: According to the heat distribution prediction result, the multi-zone heater in the high-temperature processing chamber is adjusted, and an inert gas is injected into the high-temperature processing chamber to complete the temperature control and environmental configuration of the single crystal silicon lens, which specifically includes the following steps: Determining a target temperature of each heating zone based on the predicted temperature distribution of the single crystal silicon lens; Using a feedback control algorithm, the power output of the heating zone is adjusted in real time, so that the temperature of the heater zone gradually approaches the predicted temperature distribution of the single crystal silicon lens output by the prediction model; At the same time, according to the size of the high-temperature processing chamber, the material processing requirements and the predicted temperature distribution, high-purity inert gas is selected to be injected into the chamber; When the high temperature processing operation of the single crystal silicon lens enters a stable stage, the injection rate of the gas is adjusted by a flow controller; While the inert gas is continuously injected, the gas in the cavity is continuously discharged; The injected inert gas is monitored in real time, and the injection rate of the inert gas is dynamically adjusted according to the monitored inert gas data to complete the environmental configuration.

5. The high temperature processing system for improving the refractive index uniformity of a single crystal silicon lens as claimed in claim 4, characterized in that: The target refractive index of the target single crystal silicon lens is set based on the design requirements and historical data, specifically including the following steps: Determine the optical performance requirements, mechanical stress and stress birefringence according to the actual application scenarios of single crystal silicon lenses, and obtain the design requirements of single crystal silicon lenses; The refractive index data of single crystal silicon is extracted from historical data, and the mean value, standard deviation and extreme value range of the refractive index are extracted through statistical analysis. These data are then combined with the design requirements of the single crystal silicon lens to generate the target refractive index of the single crystal silicon lens.

6. The high temperature processing system for improving the refractive index uniformity of a single crystal silicon lens as claimed in claim 5, characterized in that: The refractive index of the single crystal silicon lens is monitored in real time by a laser interferometer, and compared with the target refractive index of the target single crystal silicon lens, and the comparison result is output, which specifically includes the following steps: A laser interferometer uses a high-stability laser source to pass through a single-crystal silicon lens to obtain real-time interference fringe data, and the refractive index distribution of the single-crystal silicon lens is calculated using a fast Fourier transform algorithm; The calculated refractive index of the single crystal silicon lens is compared with the target refractive index of the single crystal silicon lens and the comparison result is output.

7. The high temperature processing system for improving the refractive index uniformity of a single crystal silicon lens as claimed in claim 6, characterized in that: The comparison results are fed back to the thermal distribution prediction model, and the thermal distribution prediction model further optimizes the thermal power distribution of the multi-zone heater according to the refractive index deviation, specifically including the following steps: Combining the refractive index comparison results with the predicted temperature distribution of the single crystal silicon lens, the area where the temperature distribution has a large error is output; The model corrects the temperature distribution of the zone and adjusts the thermal power distribution of the multi-zone heater through the error back propagation algorithm.

8. The high temperature processing system for improving the uniformity of the refractive index of a single crystal silicon lens as claimed in claim 7, characterized in that: After the heating treatment is completed, the power of the multi-zone heater is reduced and switched to a vacuum environment. The laser interferometer continues to collect and monitor the changes in the refractive index distribution during the cooling process, which specifically includes the following steps: When the heating process is completed, the power of the multi-zone heater is gradually reduced to cool the lens material, and the gas in the heating chamber is gradually pumped out to establish a low-pressure vacuum environment; The laser interferometer continuously collects the refractive index distribution of the lens, compares this data with the target refractive index, and makes dynamic adjustments based on real-time data.

9. The high temperature processing system for improving the uniformity of the refractive index of a single crystal silicon lens as claimed in claim 8, characterized in that: Generate a task report based on this task and upload the report to the system, which includes the following steps: Record all data of the heating task, operating procedures, instructions issued by all modules during the task, and response results and upload them to the system for technical personnel to analyze and optimize.

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