A high-reliability optical system optimization design method

Abstract

The invention discloses a high-reliability optical system optimization design method, comprising: carrying out mechanical and thermal simulation analysis of optical structure and optical element to obtain the intensity distribution and maximum stress distribution of the optical structure; at the same time, obtaining the frequency distribution and cumulative frequency distribution of the size change of the optical element, and recording the total number of simulations and the number of times the size change of the optical element meets the requirements; calculating the reliability of the optical structure according to the intensity distribution and the maximum stress distribution of the optical structure; at the same time, calculating the reliability of the optical element according to the total number of optical element simulations and the number of times the size change of the optical element meets the requirements; calculating the reliability of the optical system by using the reliability of the optical structure and the reliability of the optical element. On the one hand, the invention provides a quantitative evaluation of the reliability of the optical system, and quantitatively guides the design improvement of the reliability of the optical system; on the other hand, it provides a verification test for the design matching of each component of the optical system and between the components.

Description

Technical Field

[0001] The invention belongs to the technical field of optical system design, and in particular to a high-reliability optical system optimization design method. Background Art

[0002] With the development of science and technology and the military, high-reliability optical systems have extremely broad application prospects in various fields such as resource exploration, real estate evaluation, disaster reduction, environment, surveillance, military reconnaissance and surveillance, marine development, and weather forecasting, and are an important means of economic construction and national defense construction. At the same time, due to the continuous improvement of the field of view, resolution, and image quality requirements of high-reliability optical systems, coupled with the increasingly stringent volume, weight, and cost restrictions on high-reliability optical systems, the structure of high-reliability optical systems has become increasingly complex. This poses a greater challenge to the reliability of high-reliability optical systems.

[0003] During the entire working process, high-reliability optical systems often need to experience different or even very different mechanical and thermal environments with changes in the external environment. This places high demands on the strength, stiffness, and dimensional stability of optical products to adapt to different environments. If they can fully adapt to these environments, optical products can work reliably, so the design optimization of high-reliability optical systems is mostly focused on strengthening the design to avoid deformation of optical structures and mirrors. However, there are two problems in the current design optimization process. One is that there is a lack of quantitative prediction of the reliability of the optical system, and it is impossible to quantitatively guide the design optimization from the perspective of improving reliability, which leads to the reliability of the optical system going to two extremes during the design optimization process: 1) Under-design: Too much emphasis on design constraints such as volume and weight, resulting in poor adaptability of the optical system. The performance of the optical system will drop significantly if the external mechanical and thermal environment changes slightly; 2) Over-design: The optical system can fully adapt to various environmental conditions and has high reliability, but the volume and weight are seriously exceeded, resulting in inconvenience or even unusability. Another reason is that there is a lack of verification tests for the reliability of the optical system during the design optimization process, which leads to insufficient verification of the optical system's ability to adapt to various environments during the design process. Many performance degradations caused by environmental influences, such as defocus, mirror deformation, lens film shedding, etc., are not discovered until use. Due to these two reasons, it is difficult to immediately verify and evaluate the design optimization of the optical system, the design optimization is slow, and the problem discovery cycle is long, or even discovered during use. Summary of the invention

[0004] The purpose of the present invention is to provide a high-reliability optical system optimization design method to solve the problem of verification test for the components of the optical system and the design matching between the components.

[0005] In view of this, the present invention provides a high-reliability optical system optimization design method, which is characterized by comprising:

[0006] Step 1: Conduct optimization design of high-reliability optical systems and form a design plan;

[0007] Step 2: Using the design scheme as input, conduct mechanical and thermal simulation analysis of the optical structure and optical elements, substitute the external force of the optical system, the model and material parameters of the optical structure into the simulation software, and obtain the strength distribution and maximum stress distribution of the optical structure through repeated sampling simulation calculations;

[0008] At the same time, the external thermal environment of the optical system, the model and material parameters of the optical element are substituted into the simulation software, and the frequency distribution and cumulative frequency distribution of the size change of the optical element are obtained through repeated sampling simulation calculations, and the total number of simulations and the number of times the size change of the optical element meets the requirements are recorded;

[0009] Step 3, calculating the reliability of the optical structure according to the optical structure strength distribution and the maximum stress distribution;

[0010] At the same time, the reliability of the optical element is calculated based on the total number of optical element simulations and the number of times the optical element size changes meet the requirements;

[0011] Step 4, using the reliability of the optical structure and the reliability of the optical element, calculate the reliability of the optical system;

[0012] Step 5: Determine whether the reliability of the optical system meets the requirements according to the optical system design requirements. If not, repeat steps 1 to 5. If yes, conduct test verification.

[0013] Step six, conduct test verification on the optical system;

[0014] Step seven, judging whether the optical system has passed the verification test according to the test results, if not, repeating steps one to seven; if passed, saving and solidifying the optical system design.

[0015] Furthermore, in step three, the safety margin of the structural design is determined based on the fact that the optical structure strength and the maximum stress of the optical structure obey normal distribution.

[0016] Furthermore, the reliability of the optical structure is determined using the probability that the safety margin is greater than 0.

[0017] Furthermore, in step three, multiple samplings are performed by inputting the central value and standard deviation of the structural material parameters, as well as the central value and standard deviation of the structural processing dimensions, to obtain the frequency distribution of the mirror deformation.

[0018] Furthermore, the probability that the mirror deformation amount is less than a required value is determined according to the probability distribution of the mirror deformation amount.

[0019] Furthermore, in step 4, it is determined that the optical structure and the optical element are in a series relationship in terms of reliability.

[0020] Further, the optical system reliability is determined as the product of the optical structure reliability and the optical element reliability.

[0021] Furthermore, in step six, the optical system is tested and verified, including: a temperature cycle test is designed for the structural stress and mirror deformation of the optical system to verify the design. The specific conditions are as follows:

[0022] Temperature range: -50℃~+70℃;

[0023] Holding time: high and low temperature are maintained for 1 hour each;

[0024] Temperature change rate: not less than 10℃ / min;

[0025] Number of cycles: 15 times.

[0026] Furthermore, in step six, the optical system is tested and verified, including: a constant humidity test is designed for the mirror coating of the optical system to conduct design verification, and the specific conditions are as follows: the temperature in the box is raised to 40°C to preheat the test sample for 1 hour, and after the temperature of the test sample stabilizes, the humidity in the box is increased to a relative humidity of 95%±5%, and the temperature in the box is always maintained at 40°C. The test lasts for 48 hours.

[0027] Furthermore, in step six, the optical system is tested and verified, including: an impact test is designed for the structural strength of the optical system to verify the design.

[0028] The present invention achieves the following significant beneficial effects:

[0029] The implementation is simple, including carrying out high-reliability optical system optimization design and forming a design scheme; taking the design scheme as input, carrying out mechanical and thermal simulation analysis of optical structures and optical elements, substituting the external force of the optical system, the model and material parameters of the optical structure into the simulation software, and obtaining the strength distribution and maximum stress distribution of the optical structure through repeated sampling simulation calculations; at the same time, substituting the external thermal environment of the optical system, the model and material parameters of the optical element into the simulation software, and obtaining the frequency distribution and cumulative frequency distribution of the size change of the optical element through repeated sampling simulation calculations, and recording the total number of simulations and the number of times the size change of the optical element meets the requirements; calculating the reliability of the optical structure according to the strength distribution and maximum stress distribution of the optical structure; at the same time, calculating the reliability of the optical element according to the total number of optical element simulations and the number of times the size change of the optical element meets the requirements; calculating the reliability of the optical system by using the reliability of the optical structure and the reliability of the optical element, and combining the simulation analysis, on the one hand, giving a quantitative evaluation of the reliability of the optical system, and quantitatively guiding the design improvement of the reliability of the optical system; on the other hand, giving a verification test for the design matching of each component of the optical system and between each component. This method can verify the reliability of the optical system in advance in the design stage or through short-term tests, help optimize the design of high-reliability optical systems, and improve design efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flow chart of the high-reliability optical system optimization design method of the present invention;

[0031] Figure 2 A schematic diagram of maximum stress distribution of the high-reliability optical system optimization design method of the present invention;

[0032] Figure 3 is a schematic diagram of the frequency distribution of the thickness change ΔH of the lens of the present invention;

[0033] Figure 4 is a schematic diagram of the cumulative frequency distribution of the lens thickness change ΔH of the present invention;

[0034] Figure 5 is a schematic diagram of the frequency distribution of the thickness change ΔH of the lens of the present invention;

[0035] Figure 6 Schematic diagram of cumulative frequency distribution of lens thickness change ΔH of the present invention. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are all in very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0037] It should be noted that, in order to clearly explain the content of the present invention, the present invention specifically cites multiple embodiments to further illustrate different implementations of the present invention, wherein the multiple embodiments are enumerated rather than exhaustive. In addition, for the sake of brevity of explanation, the contents mentioned in the previous embodiments are often omitted in the subsequent embodiments. Therefore, the contents not mentioned in the subsequent embodiments can refer to the previous embodiments accordingly.

[0038] Although the invention can be extended in various forms of modification and substitution, some specific implementation examples are listed in the specification and described in detail. It should be understood that the starting point of the inventor is not to limit the invention to the specific embodiments described. On the contrary, the starting point of the inventor is to protect all improvements, equivalent substitutions and modifications made within the spirit or scope defined by this claim. The same component number may be used in all drawings to represent the same or similar parts.

[0039] See also Figure 1 , a high-reliability optical system optimization design method, comprising:

[0040] S1, carry out high-reliability optical system optimization design and form a design plan;

[0041] S2, using the design scheme as input, conduct mechanical and thermal simulation analysis of optical structures and optical elements, substitute the external force of the optical system, the model and material parameters of the optical structure into the simulation software, and obtain the strength distribution R~N(μR,σR) and maximum stress distribution S~N(μS,σS) of the optical structure through repeated sampling simulation calculations, where R represents the strength of the optical structure, N(μR,σR) represents the normal distribution with μR as the mean and σR as the standard deviation; S represents the maximum stress of the optical structure, and N(μS,σS) represents the normal distribution with μS as the mean and σS as the standard deviation;

[0042] At the same time, the external thermal environment of the optical system, the model and material parameters of the optical element are substituted into the simulation software. Through repeated sampling simulation calculations, the frequency distribution and cumulative frequency distribution of the dimensional change (ΔH) of the optical element are obtained, and the total number of simulations n and the number of times the dimensional change (ΔH) of the optical element meets the requirement (limit) s are recorded.

[0043] S3, calculate the optical structure reliability P (R>S) based on the optical structure strength distribution R~N (μR, σR) and the maximum stress distribution S~N (μS, σS).

[0044] At the same time, the reliability of the optical element P (ΔH) is calculated based on the total number of optical element simulations n and the number of times the optical element size change (ΔH) meets the requirement (limit) s. <limit)。

[0045] S4. Calculate the reliability R of the optical system by using the optical structure reliability P(R > S) and the optical component reliability P(ΔH < limit). sys .

[0046] S5. Judge whether the reliability of the optical system meets the requirements according to the optical system design requirements. If not, repeat steps 1 to 5; if so, conduct experimental verification.

[0047] S6. Conduct experimental verification on the optical system.

[0048] S7. Judge whether the optical system passes the verification test according to the test results. If not, repeat S1 to S7; if so, save and solidify the optical system design.

[0049] In an embodiment of the present application, specifically, in S3, "calculate the optical structure reliability P(R > S) according to the strength distribution R~N(μ R , σ R ) and the maximum stress distribution S~N(μ S , σ S )" includes:

[0050] a. If the maximum stress S of the structure follows a normal distribution with parameters μ S and σ S , and the strength R follows a normal distribution with parameters μ R and σ R , then Z = R - S also follows a normal distribution, that is:

[0051]

[0052] The meanings of the symbols in the formula are as follows:

[0053] Z: The difference between the structural strength R and the maximum stress S of the structure, that is, the safety margin of the structural design;

[0054] With μ R - μ S as the mean value, as the standard deviation of the normal distribution.

[0055] b. From the strength perspective, to ensure that the safety margin Z = R - S > 0 during use, the structure is considered reliable. The optical structure reliability is equivalent to the probability that the structural safety margin is greater than 0, that is, P(R > S) = P(Z > 0). The optical structure reliability P(R > S) can be calculated according to formula (1).

[0056]

[0057] The meanings of the symbols in the formula are as follows:

[0058] P(R > S): Optical structure reliability;

[0059] P(Z > 0): Probability that the structural safety margin Z is greater than 0;

[0060] Ф(*): Represents the standard normal distribution function;

[0061] From μ R 、μ S 、σ R and σ S The value obtained by substituting and calculating.

[0062] In an embodiment of the present application, specifically, in S3, "According to the total number of simulations n and the number of times s that the optical element size change (ΔH) meets the requirement (limit), calculate the reliability P(ΔH < limit) of the optical element", including:

[0063] a. For the optical element, the thermal simulation under prestress conditions can be used to analyze the mirror surface deformation. By inputting the central value and standard deviation of the structural material parameters, as well as the central value and standard deviation of the structural processing size, and conducting multiple samplings, the frequency distribution of the mirror surface deformation amount can be obtained. When the number of samplings is large, the frequency distribution of the mirror surface deformation amount can be approximated as the probability distribution of the deformation amount. According to the probability distribution of the deformation amount, the probability that the mirror surface deformation amount is less than the required value can be predicted, that is, the reliability of the mirror surface.

[0064] b. Substitute the total number of simulation samplings n and the number of times s that the optical element size change (ΔH) meets the requirement (limit) into formula (2) to calculate the reliability P(ΔH < limit) of the optical element.

[0065]

[0066] The meanings of the symbols in the formula are as follows:

[0067] ΔH: Optical element size change;

[0068] limit: Upper limit value of the optical element size change;

[0069] P(ΔH < limit): Probability that the optical element size change is less than the upper limit value;

[0070] n: Total number of simulation samplings;

[0071] s: Number of simulation samplings when the optical element size change is less than the upper limit value.

[0072] In an embodiment of the present application, specifically, in S4, "Using the optical structure reliability P(R > S) and the optical element reliability P(ΔH < limit), calculate the reliability R of the optical systemsys ”, including:

[0073] a. The optical system is mainly composed of an optical structure and optical components. In the study of the optical structure, it is found that the failure of the optical structure is generally a strength failure when the stress at the weak link or the maximum stress of the structure exceeds the material strength. For optical components, their failure modes are mainly manifested as the degradation of image quality caused by the decrease in the surface shape accuracy of the mirror surface. Therefore, the optical structure and optical components are in a series relationship in terms of reliability, and the reliability of the optical system is the product of the reliability of the optical structure and the reliability of the optical components.

[0074] b. Using the reliability of the optical structure P(R > S) and the reliability of the optical components P(ΔH < limit), according to formula (3), calculate the reliability R of the optical system sys .

[0075] R sys = P(R > S)·P(ΔH < limit) (3)

[0076] The meanings of the symbols in the formula are as follows:

[0077] R sys : The reliability of the optical system;

[0078] P(R > S): The reliability of the optical structure;

[0079] P(ΔH < limit): The probability that the size change of the optical component is less than the upper limit value.

[0080] In an embodiment of the present application, specifically, in S6, "conducting experimental verification on the optical system" includes:

[0081] a. For the structural stress and mirror surface deformation of the optical system, a temperature cycle test is designed for design verification, and the specific conditions are as follows:

[0082] Temperature range: -50°C to +70°C;

[0083] Holding time: 1 h for both high and low temperatures;

[0084] Temperature change rate: not less than 10°C / min;

[0085] Number of cycles: 15 times.

[0086] b. For the mirror surface coating of the optical system, a constant humidity and heat test is designed for design verification, and the specific conditions are as follows:

[0087] Raise the temperature inside the chamber to 40°C to preheat the test sample for 1 h. After the temperature of the test sample is stable, add humidity inside the chamber to a relative humidity of 95% ± 5%, and keep the temperature inside the chamber at 40°C all the time. The test duration is 48 h.

[0088] c. Aiming at the structural strength of the optical system, an impact test was designed to verify the design. The specific conditions are as follows:

[0089] ±X, ±Y, ±Z axis, twice in positive and negative directions for each axis, 12 times in total. The impact spectrum is as follows:

[0090] Starting frequency: 100Hz;

[0091] Starting amount: 100g;

[0092] Inflection point frequency: 800Hz;

[0093] Inflection point magnitude: 4000g;

[0094] End frequency: 5000Hz;

[0095] End weight: 4000g.

[0096] d. In view of the design matching of optical structure and optical elements in the optical system, a temperature-vibration comprehensive test was designed to verify the design. The specific conditions are as follows:

[0097] Temperature range: -50℃~+70℃;

[0098] Vibration direction: X, Y, Z;

[0099] Number of cycles: 3 temperature cycles;

[0100] Temperature change rate: not less than 10℃ / min;

[0101] Vibration spectrum:

[0102] 10Hz~100Hz:+3dB / oct;

[0103] 100Hz~1500Hz:0.1g2 / Hz;

[0104] 1500Hz~2000Hz:-3dB / oct;

[0105] Vibration time: 6 minutes per axis;

[0106] Temperature holding time: 1h6min, with vibration applied for the last 6min.

[0107] Test: The following specific test data from Table 1 to Table 3 verify the technical effect of the present invention.

[0108] Table 1 Parameters of certain optical structure materials

[0109]

[0110] Table 2 Dimensional parameters of an optical structure

[0111]

[0112] Table 3 Parameters of an optical element

[0113]

[0114] As a specific example, in step S2, taking an aluminum alloy optical structure as an example, the maximum force that the structure bears due to overload is F=1kN~5kN, by inputting the center value and standard deviation of the structural material parameters (as shown in Table 1), and the center value and standard deviation of the structural processing dimensions (as shown in Table 2). Repeated sampling simulation calculation is performed, according to Figure 2 As shown, we can get the maximum stress distribution S~N(25.6,2.3) and the material strength distribution R~N(315,20). Figure 2 , the maximum stress distribution of the optical structure, such as Figure 2 As shown in the figure. According to the simulation results of the structural sampling, the fluctuation range of the maximum stress of the structure is 19MPa to 33MPa, the sample mean is 25.6MPa, the standard deviation is 2.3MPa, and the frequency of the maximum stress of the structure is symmetrically distributed with a mean of 25.6MPa, and the maximum frequency appears in the range of 26MPa to 27MPa. This figure intuitively reflects that the maximum stress of the structure obeys the normal distribution. The normal distribution can be used to quantitatively describe the maximum stress of the structure and participate in the calculation of structural reliability.

[0115] Take an optical element as an example. The material is K9 glass, with an elastic modulus of 81.3 GPa, a Poisson's ratio of 0.209, a thermal expansion coefficient of 7.5 × 10-6 / °C, and a thermal conductivity of 0.0012 W / mm / °C. The other parameters are shown in Table 3. The ambient temperature is 60°C ± 2°C. According to the above parameters, 800 sampling simulation analyses are performed, and the frequency distribution and cumulative frequency distribution of the lens thickness change can be obtained as shown in the following figure. Figure 3 and Figure 4 As shown. The total number of simulations n = 800 and the number of times the optical element size changes meet the requirements (ΔH < λ / 60) s = 768. Figure 3 , distribution of optical component size change (ΔH). According to the sampling simulation results of optical components, the fluctuation range of optical component size change (ΔH) is 3nm to 14nm, the sample mean is 7.98nm, the standard deviation is 1.49nm, and the frequency of optical component size change (ΔH) is symmetrically distributed with a mean of 7.98nm, and the maximum frequency occurs between 7nm and 8nm. This figure shows that the distribution of optical component size change (ΔH) in the sampling simulation is symmetrical, without obvious eccentric deformation, and the statistical results of optical component size change (ΔH) can be used to estimate the reliability of optical components. Figure 4,Accumulated frequency distribution of optical element size change (ΔH),According to the simulation results of optical element sampling, the fluctuation range of optical element size change (ΔH) is 3nm to 14nm. As the fluctuation range of optical element size change (ΔH) increases, the cumulative frequency gradually increases, and the frequency of satisfying ΔH<λ / 60=10.55nm is 0.96, that is, 96% of the samples have an optical element size change (ΔH) not greater than λ / 60=10.55nm. This figure intuitively reflects the frequency of optical element size change (ΔH) not greater than the limit value (λ / 60), which represents the optical element reliability P(ΔH<λ / 60)=0.96.

[0116] As a specific example, in step S3, the maximum stress distribution S~N(25.6,2.3) in MPa and the material strength distribution R~N(315,20) in MPa are calculated according to formula (1), and the reliability of the optical structure can be obtained as P(R>S)=1-3.4×10-47, which is close to 1.

[0117] Taking a certain optical element as an example, 800 sampling simulation analyses were performed, the total number of simulations n = 800, the number of times the size change of the optical element met the requirement (ΔH < λ / 60) s = 768, and the calculation results show that the reliability of the optical element P (ΔH < λ / 60) = 0.96.

[0118] As a specific embodiment, in step S4, taking a certain optical system as an example, the reliability of the optical structure is P(R>S)=1-3.4×10-47, and the reliability of the optical element is P(ΔH<λ / 60)=0.96. Calculation shows that the reliability of the optical system is Rsys=P(R>S)·P(ΔH<λ / 60)=0.96.

[0119] As a specific embodiment, in step S5, taking a certain optical system as an example, Rsys=0.96, which is difficult to meet the high reliability requirements of the optical system. To further improve the optical reliability, the change of the lens thickness H is suppressed by appropriately reducing the lens thickness H.

[0120] According to the optical design, the lens thickness and radius center values ​​are adjusted to 19mm and 142mm, and the standard deviation remains unchanged. Substitute into the model and re-perform 4000 sampling simulation analysis, the frequency distribution and cumulative frequency distribution of lens thickness changes can be obtained as follows: Figure 5 and Figure 6 As shown. According to the simulation results, the reliability of the optical element P(ΔH<λ / 60)=0.998. Figure 5After the improvement, the distribution of the size change (ΔH) of the optical element, according to the sampling simulation results of the optical element, the fluctuation range of the size change (ΔH) of the optical element is 4.5nm to 11nm, the sample mean is 7.68nm, the standard deviation is 0.956nm, and the frequency of the size change (ΔH) of the optical element is symmetrically distributed with a mean of 7.68nm, and the maximum frequency appears in the range of 7.5nm to 8nm. This figure shows that the distribution of the size change (ΔH) of the optical element in the sampling simulation is symmetrical, without obvious eccentric deformation, and the statistical results of the size change (ΔH) of the optical element can be used to estimate the reliability of the optical element. Reference Figure 6 After the improvement, the cumulative frequency distribution of the optical element size change (ΔH) is shown in Figure 1. According to the simulation results of optical element sampling, the fluctuation range of the optical element size change (ΔH) is 4.5nm to 11nm. As the fluctuation range of the optical element size change (ΔH) increases, the cumulative frequency gradually increases. The frequency of satisfying ΔH<λ / 60=10.55nm is 0.998, that is, 99.8% of the samples have an optical element size change (ΔH) that is not greater than λ / 60=10.55nm. This figure intuitively reflects the frequency of the optical element size change (ΔH) not greater than the limit value (λ / 60), which represents the optical element reliability P(ΔH<λ / 60)=0.998.

[0121] As a specific embodiment, in step S6, an experiment is carried out to verify the optical system, and the specific experiment is as follows:

[0122] 1) Temperature Cycle

[0123] Temperature range: -40℃~+65℃;

[0124] Holding time: high and low temperature are maintained for 1 hour each;

[0125] Temperature change rate: not less than 10℃ / min;

[0126] Number of cycles: 15 times.

[0127] 2) Constant heat and humidity

[0128] Raise the temperature in the box to 40℃ to preheat the test sample for 1 hour. After the temperature of the test sample stabilizes, increase the humidity in the box to a relative humidity of 95%±5%. The temperature in the box is always maintained at 40℃. The test lasts for 48 hours.

[0129] 3) Impact

[0130] ±X, ±Y, ±Z axis, twice in positive and negative directions for each axis, 12 times in total. The impact spectrum is as follows:

[0131] Starting frequency: 100Hz;

[0132] Starting amount: 100g;

[0133] Inflection point frequency: 800Hz;

[0134] Inflection point magnitude: 4000g;

[0135] End frequency: 5000Hz;

[0136] End weight: 4000g.

[0137] 4) Temperature-vibration comprehensive test

[0138] Temperature range: -50℃~+70℃;

[0139] Vibration direction: X, Y, Z;

[0140] Number of cycles: 3 temperature cycles;

[0141] Temperature change rate: not less than 10℃ / min;

[0142] Vibration spectrum:

[0143] 10Hz~100Hz:+3dB / oct;

[0144] 100Hz~1500Hz:0.1g2 / Hz;

[0145] 1500Hz~2000Hz:-3dB / oct;

[0146] Vibration time: 6 minutes per axis;

[0147] Temperature holding time: 1h6min, with vibration applied for the last 6min.

[0148] As a specific embodiment, in step S7, it is determined whether the optical system has passed the verification test based on the test results. If not, steps S1 to S7 are repeated; if passed, the optical system design is saved and solidified.

[0149] In summary, it can be obtained that the reliability of the optical system is Rsys=P(R>S)·P(ΔH<λ / 60)=0.998, which can meet the high reliability requirements of the optical system.

[0150] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0151] The implementation is simple, including carrying out high-reliability optical system optimization design and forming a design scheme; taking the design scheme as input, carrying out mechanical and thermal simulation analysis of optical structures and optical elements, substituting the external force of the optical system, the model and material parameters of the optical structure into the simulation software, and obtaining the strength distribution and maximum stress distribution of the optical structure through repeated sampling simulation calculations; at the same time, substituting the external thermal environment of the optical system, the model and material parameters of the optical element into the simulation software, and obtaining the frequency distribution and cumulative frequency distribution of the size change of the optical element through repeated sampling simulation calculations, and recording the total number of simulations and the number of times the size change of the optical element meets the requirements; calculating the reliability of the optical structure according to the strength distribution and maximum stress distribution of the optical structure; at the same time, calculating the reliability of the optical element according to the total number of optical element simulations and the number of times the size change of the optical element meets the requirements; calculating the reliability of the optical system by using the reliability of the optical structure and the reliability of the optical element, and combining the simulation analysis, on the one hand, giving a quantitative evaluation of the reliability of the optical system, and quantitatively guiding the design improvement of the reliability of the optical system; on the other hand, giving a verification test for the design matching of each component of the optical system and between each component. This method can verify the reliability of the optical system in advance in the design stage or through short-term tests, help optimize the design of high-reliability optical systems, and improve design efficiency.

[0152] According to the technical solution and concept of the present invention, there may be any other suitable changes. For those skilled in the art, all these replacements, adjustments and improvements should fall within the protection scope of the appended claims of the present invention.

Claims

1. A high-reliability optical system optimization design method, characterized in that: include: Step 1: Conduct optimization design of high-reliability optical systems and form a design plan; Step 2: Using the design scheme as input, conduct mechanical and thermal simulation analysis of the optical structure and optical elements, substitute the external force of the optical system, the model and material parameters of the optical structure into the simulation software, and obtain the strength distribution and maximum stress distribution of the optical structure through repeated sampling simulation calculations; At the same time, the external thermal environment of the optical system, the model and material parameters of the optical element are substituted into the simulation software, and the frequency distribution and cumulative frequency distribution of the size change of the optical element are obtained through repeated sampling simulation calculations, and the total number of simulations and the number of times the size change of the optical element meets the requirements are recorded; Step 3, calculating the reliability of the optical structure according to the optical structure strength distribution and the maximum stress distribution; At the same time, the reliability of the optical element is calculated based on the total number of optical element simulations and the number of times the optical element size changes meet the requirements; Step 4, using the reliability of the optical structure and the reliability of the optical element, calculate the reliability of the optical system; Step 5: Determine whether the reliability of the optical system meets the requirements according to the optical system design requirements. If not, repeat steps 1 to 5. If yes, conduct test verification. Step six, conduct test verification on the optical system; Step seven, judging whether the optical system has passed the verification test according to the test results, if not, repeating steps one to seven; if passed, saving and solidifying the optical system design.

2. The high-reliability optical system optimization design method according to claim 1, characterized in that: In step three, the safety margin of the structural design is determined based on the fact that the optical structure strength and the maximum stress of the optical structure follow a normal distribution.

3. The high-reliability optical system optimization design method according to claim 2, characterized in that: The reliability of the optical structure is determined by utilizing the probability that the safety margin is greater than 0.

4. The high-reliability optical system optimization design method according to claim 1, characterized in that: In step three, multiple samplings are performed by inputting the central value and standard deviation of the structural material parameters, as well as the central value and standard deviation of the structural processing dimensions, to obtain the frequency distribution of the mirror deformation.

5. The high-reliability optical system optimization design method according to claim 4, characterized in that: The probability that the mirror deformation amount is less than the required value is determined according to the probability distribution of the mirror deformation amount.

6. The high-reliability optical system optimization design method according to claim 1, characterized in that: In step 4, it is determined that the optical structure and the optical element are in a series relationship in terms of reliability.

7. The high-reliability optical system optimization design method according to claim 6, characterized in that: The reliability of the optical system is determined as the product of the reliability of the optical structure and the reliability of the optical element.

8. The high-reliability optical system optimization design method according to claim 6, characterized in that: In step six, the optical system is tested and verified, including: a temperature cycle test is designed for the structural stress and mirror deformation of the optical system to verify the design. The specific conditions are as follows: Temperature range: -50℃~+70℃; Holding time: high and low temperature are maintained for 1 hour each; Temperature change rate: not less than 10℃ / min; Number of cycles: 15 times.

9. The high-reliability optical system optimization design method according to claim 6, characterized in that: In step six, the optical system is tested and verified, including: a constant humidity test is designed for the mirror coating of the optical system to verify the design. The specific conditions are as follows: the temperature in the box is raised to 40°C to preheat the test sample for 1 hour. After the temperature of the test sample stabilizes, the humidity in the box is increased to a relative humidity of 95%±5%. The temperature in the box is always maintained at 40°C. The test lasts for 48 hours.

10. The high-reliability optical system optimization design method according to claim 6, characterized in that: In step six, the optical system is tested and verified, including: an impact test is designed for the structural strength of the optical system to verify the design. The specific conditions are as follows: ±X, ±Y, ±Z axes, two times in each positive and negative direction, a total of 12 times, the impact spectrum is as follows: Starting frequency: 100Hz; Starting amount: 100g; Inflection point frequency: 800Hz; Inflection point magnitude: 4000g; End frequency: 5000Hz; End weight: 4000g.

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