Optical engine polarization balance optimization method and system

Abstract

The present invention relates to the field of ground calibration and testing of spacecraft, and specifically to a method and system for optimizing polarization balance of an optical engine, the method comprising: establishing a Jones matrix of an optical engine polarization film, deriving an optimal analytical expression of polarization parameters of the optical engine film, and selecting a suitable initial film structure; establishing a mathematical model of simulation accuracy of extinction ratio and star point position, deriving a target value of the extinction ratio, and using it as a screening condition to complete the screening of the selected initial structure; establishing a polarization balance evaluation function of the optical engine film, combining a genetic algorithm with a least squares method, and optimizing the screened optical engine film; evaluating the optimized optical engine film according to the target value of the extinction ratio, and selecting the optimal optical engine film. The present invention adopts an optical engine polarization balance optimization method to improve the extinction ratio of the optical engine while expanding its tolerance to the aperture angle of incident light, thereby improving the simulation accuracy of the star map.

Description

Technical Field

[0001] The present invention relates to the field of ground calibration and testing of spacecraft, and in particular to a method and system for optimizing polarization balance of an optical engine. Background Art

[0002] Optical engines are used in the field of ground calibration and testing of spacecraft. The optical engine in the weak starlight simulation device has polarization aberration, which causes a large amount of non-imaging polarized stray light to be mixed in the simulated star map it outputs, which will not only cause the energy center position of each star point in the simulated star map to shift, reducing the simulation accuracy of the star map, but will even submerge some star points in the simulated star map, reducing the reliability of the test.

[0003] In the prior art, methods such as reconstructing the optical engine by splicing multiple polarization beam splitting prisms, optimizing the polarization film in the optical engine, and using 3M prism as the polarizing element of the optical engine are usually used. These methods all suppress the generation of stray light by improving the extinction ratio of the optical engine. However, they have problems such as large size, low energy utilization rate, and small tolerance for the aperture angle of incident light, which restrict the further improvement of the star map simulation accuracy of the existing weak starlight simulation device, making it difficult to apply the current weak starlight simulation device to the ground calibration and test experiments of high-end spacecraft.

[0004] Therefore, it is necessary to provide a new method and system for optimizing polarization balance of an optical engine. Summary of the invention

[0005] Based on the above problems existing in the prior art, an object of an embodiment of the present invention is to provide an optical engine polarization balance optimization method, which adopts the optical engine polarization balance optimization method to improve the extinction ratio of the optical engine while expanding its tolerance to the aperture angle of the incident light, thereby improving the accuracy of star map simulation.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a method for optimizing polarization balance of an optical engine, comprising:

[0007] S1, establish the Jones matrix of the optical engine polarization film, derive the optimal analytical formula of the polarization parameters of the optical engine film, and use it as the optimization target, and select the optical engine polarization balance film close to the optimization target as the initial structure;

[0008] S2, establishing a mathematical model of extinction ratio and star point position simulation accuracy, deriving an extinction ratio target value based on the theoretical value of the star point position simulation accuracy, using it as a screening condition for the polarization balance film of the optical engine, and screening out polarization films that meet the extinction ratio condition from the initial structure;

[0009] S3, establishing a polarization balance evaluation function for the optical engine film, enriching the selected polarization film structure through a genetic algorithm and optimizing it using a damped least squares method, and finally calculating the polarization balance evaluation function value of the optimized film and arranging them in ascending order;

[0010] S4, evaluating the optimized optical engine film according to the extinction ratio target value, and selecting the optimal optical engine film.

[0011] Further, in S1, the optical engine polarization film Jones matrix is:

[0012]

[0013] Among them, i is an imaginary number, is the incident light aperture angle of the central field of view, T p is the transmittance of P light in the transmitted light field, T s is the transmittance of S light in the transmitted light field, Δ=(Δs+Δp) / 2 is the average phase, and δ=Δs-Δp is the phase difference.

[0014] Furthermore, in S1, the optimal analytical formula for the polarization parameter of the optical engine film is: δ = 0 and (T p -T s ) / (T p +T s )=0, where T p is the transmittance of P light in the transmitted light field, T s is the transmittance of S light in the transmitted light field.

[0015] Furthermore, in S2, the mathematical model expression of the extinction ratio and the simulation accuracy of the star point position is:

[0016]

[0017] Among them, m i is the grayscale of the edge point, θ is the simulation accuracy of the star point position, and f′ is the focal length of the optical system.

[0018] Further, in S3, the polarization balance evaluation function expression of the optical engine film is:

[0019]

[0020] Where m and n represent the number of sampling points in the x-axis and y-axis directions of the pupil, respectively. is the transmittance attenuation corresponding to the current pupil sampling point (m, n), R(m, n) = δ(m, n) is the current value of the phase delay corresponding to the current pupil sampling point (m, n), ΔD(m, n) and ΔR(m, n) are tolerances, is the transmittance attenuation, is the phase delay target value.

[0021] Furthermore, in S3, in order to reduce the number of times the initial structure is selected, the diversity of the films to be optimized should be increased, including: using the thickness of the screened polarizing film as an optimization variable, and using operations such as crossover and mutation in the genetic algorithm to enrich the number of optical engine films to 2H.

[0022] Furthermore, it also includes calculating the polarization balance evaluation function values ​​corresponding to the 2H screened polarization films respectively, arranging them in order from small to large, selecting the first H films as secondary films to be optimized, and optimizing the film thickness using the damped least squares method.

[0023] Furthermore, S3 also includes recording the optimized film structure, calculating the polarization balance evaluation function value corresponding to the optimized film and arranging them in ascending order.

[0024] Furthermore, in S4, the polarization balance evaluation function value corresponding to the optimized film is evaluated based on the extinction ratio target value obtained in step S2 as the screening condition of the optical engine polarization balance film. If the extinction ratio screening condition is met, the optimal film structure is recorded and selected. If the screening condition is not met, the initial structure of the film obtained in step S1 is replaced and re-optimized.

[0025] An optical engine polarization balance optimization system is applied to the above optical engine polarization balance optimization method, and the optical engine polarization balance optimization system comprises:

[0026] The derivation module is used to establish the Jones matrix of the optical engine polarization film, derive the optimal analytical expression of the polarization parameters of the optical engine film, and use it as the optimization target. At the same time, the optical engine polarization balance film close to the optimization target is selected as the initial structure;

[0027] Modeling module, used to establish the mathematical model of extinction ratio and star point position simulation accuracy, obtain the extinction ratio target value according to the theoretical value of star point position simulation accuracy, use it as the screening condition of the polarization balance film of the optical engine, and screen out the polarization film that meets the extinction ratio condition from the initial structure;

[0028] The optimization module is used to establish the polarization balance evaluation function of the optical engine film, enrich the selected polarization film structure through the genetic algorithm and optimize it using the damped least squares method, and finally calculate the polarization balance evaluation function value of the optimized film and arrange it in ascending order;

[0029] The screening module is used to evaluate the optimized optical engine film according to the extinction ratio target value and select the optimal optical engine film.

[0030] The beneficial effects of the present invention are as follows: the optical engine polarization balance optimization method of the present invention includes: establishing the Jones matrix of the optical engine polarization film, deriving the optimal analytical expression of the polarization parameter of the optical engine film, and taking it as the optimization target, and selecting the optical engine polarization balance film close to the optimization target as the initial structure; establishing a mathematical model of extinction ratio and star point position simulation accuracy, deriving the extinction ratio target value according to the theoretical value of the star point position simulation accuracy, taking it as the screening condition of the optical engine polarization balance film, and screening the polarization film that meets the extinction ratio condition from the initial structure; establishing the polarization balance evaluation function of the optical engine film, enriching the selected polarization film structure through the genetic algorithm and optimizing it by the damped least square method, and calculating the polarization balance evaluation function value of the optimized film at the same time, and arranging it in ascending order; evaluating the optimized optical engine film according to the extinction ratio target value, and selecting the optimal optical engine film structure. The present invention adopts the optical engine polarization balance optimization method to improve the extinction ratio of the optical engine while expanding its tolerance to the incident light aperture angle, thereby improving the star map simulation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0032] In the figure:

[0033] Figure 1 A flow chart of a method for optimizing polarization balance of an optical engine provided in Embodiment 1 of the present invention;

[0034] Figure 2 A graph showing transmittance attenuation and phase difference of an optical engine film provided in the first embodiment of the present invention;

[0035] Figure 3 A comparison chart of the test results of corrected sampling point position errors provided in the first embodiment of the present invention;

[0036] Figure 4 A schematic diagram of a module of an optical engine polarization balance optimization system provided in Embodiment 2 of the present invention;

[0037] Figure 5 This is a schematic diagram of the structure of an optical engine polarization balance optimization system provided in Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] First embodiment:

[0040] The first embodiment of the present invention provides an optical engine polarization balance optimization method, including: establishing an optical engine polarization film Jones matrix, deriving the optimal analytical expression of the polarization parameters of the optical engine film, and taking it as the optimization target, and selecting the optical engine polarization balance film close to the optimization target as the initial structure; establishing a mathematical model of extinction ratio and star point position simulation accuracy, deriving the extinction ratio target value according to the theoretical value of the star point position simulation accuracy, taking it as the screening condition of the optical engine polarization balance film, and screening the polarization film that meets the extinction ratio condition from the initial structure; establishing a polarization balance evaluation function of the optical engine film, enriching the selected polarization film structure through a genetic algorithm and optimizing it using the damped least squares method, and calculating the polarization balance evaluation function value of the optimized film at the same time, and arranging it in ascending order; evaluating the optimized optical engine film according to the extinction ratio target value, and selecting the optimal optical engine film structure. The present invention adopts an optical engine polarization balance optimization method to improve the extinction ratio of the optical engine while expanding its tolerance to the incident light aperture angle, thereby improving the star map simulation accuracy.

[0041] The following is a detailed description of the implementation details of the optical engine polarization balance optimization method of this embodiment. The following content is only for the convenience of understanding the implementation details provided, and is not necessary for the implementation of this solution. The specific process of this embodiment is as follows: Figure 1 As shown, this embodiment is applied to an optical engine polarization balance optimization system.

[0042] Step S1, establish the Jones matrix of the optical engine polarization film, derive the optimal analytical expression of the polarization parameters of the optical engine film, and use it as the optimization target, and select the optical engine polarization balance film close to the optimization target as the initial structure.

[0043] Specifically, since the polarization aberration corresponding to the central field of view of the optical engine has a minimum characteristic compared to the full field of view, it is more restrictive to use the polarization parameters corresponding to the central field of view of the optical engine as the optimization target.

[0044] The Jones matrix of the optical engine polarization film corresponding to the central field of view is:

[0045]

[0046] Among them, i is an imaginary number, is the incident light aperture angle of the central field of view, T p is the transmittance of P light in the transmitted light field, T s is the transmittance of S light in the transmitted light field, Δ=(Δs+Δp) / 2 is the average phase, and δ=Δs-Δp is the phase difference.

[0047] In order to determine the influence of polarization aberration of the optical engine film on the incident light, the incident light vibration direction is preset along the x-axis. At this time, after passing through the optical engine film, the polarization state expression of the outgoing light is:

[0048]

[0049] Among them, E x is the electric field intensity along the x direction, E y is the electric field intensity along the y direction, i is an imaginary number, is the incident light aperture angle of the central field of view, T p is the transmittance of P light in the transmitted light field, T s is the transmittance of S light in the transmitted light field, Δ=(Δs+Δp) / 2 is the average phase, and δ=Δs-Δp is the phase difference.

[0050] According to the expression of the polarization state of the outgoing light, the transmission light path of the optical engine is affected by the aperture angle of the incident light. Due to the combined effect of the transmitted light intensity of S light and P light and the phase difference of S light and P light, the outgoing light will deviate from the polarization state of the incident light. Therefore, the aperture angle of the incident light The transmitted light intensity of S light and P light and the phase difference of S light and P light result in that when the incident light is reflected by the star map display device and passes through the optical engine again, the optical engine with polarization function will absorb the light whose transmitted vibration direction is not perpendicular to the optical axis of the analyzer, causing the generation of stray light in the optical engine.

[0051] Using the single variable method, the incident light aperture angle is calculated separately The influence of the transmitted light intensity of S light and P light and the phase difference of S light and P light on the polarization state of the outgoing light is studied, and then the optimal analytical formula for the polarization parameters of the optical engine thin film is obtained.

[0052] If we only consider the effect of phase difference on the polarization state of the outgoing light, we can assume that T = T s =T p , at this time, the formula for the influence of phase difference on the polarization state of the outgoing light is:

[0053]

[0054] Among them, E x is the electric field intensity along the x direction, E y is the electric field intensity along the y direction, i is an imaginary number, Δ is the average phase, T is the transmittance, δ is the phase difference, and θ is the incident angle.

[0055] According to the formula for the effect of phase difference on the polarization state of the outgoing light, the transmittance T will not change the polarization state of the outgoing light, while the phase difference δ and the incident angle θ in the matrix will change the polarization state of the outgoing light, and θ is a system parameter that cannot be changed. When δ is closer to 0, the polarization state of the outgoing light is closer to the polarization state of the incident light, which can effectively suppress the change in polarization state caused by oblique incidence.

[0056] If only the effect of transmittance on the polarization state of the outgoing light is considered, δ=0 is preset, and the formula for the effect of phase difference on the polarization state of the outgoing light is:

[0057]

[0058] Among them, E x is the electric field intensity along the x direction, E y is the electric field intensity along the y direction, i is an imaginary number, is the incident light aperture angle of the central field of view, T p is the transmittance of P light in the transmitted light field, T s is the transmittance of S light in the transmitted light field, and Δ=(Δs+Δp) / 2 is the average phase.

[0059] Furthermore, (T p -T s ) / (T p +T s ) represents the transmittance attenuation. According to the preset δ=0, the formula for the influence of the phase difference on the polarization state of the outgoing light shows that when T p -T s The larger the difference, the greater the transmittance attenuation (T p -T s ) / (T p +T s ) is larger, the polarization state of the outgoing light will inevitably change dramatically. For obliquely incident light, is always non-zero, so if T p =T s , the polarization state of the outgoing light is closer to the polarization state of the incident light.

[0060] Therefore, the incident light aperture angle will inevitably affect the polarization state of the outgoing light. To ensure the stability of the polarization state, under ideal conditions, the phase delay and transmittance attenuation meet the optimal conditions, that is, the optimal analytical formula of the optical engine film polarization parameters is: δ = 0 and (T p -T s ) / (T p +T s )=0.

[0061] Step S2, establishing a mathematical model of extinction ratio and star point position simulation accuracy, deriving an extinction ratio target value according to a theoretical value of star point position simulation accuracy, using it as a screening condition for the polarization balance film of the optical engine, and screening out polarization films that meet the extinction ratio condition from the initial structure.

[0062] Specifically, the mathematical model of extinction ratio and star point position simulation accuracy is established: the preset star point is represented by 9 pixel primitives of 3×3, and the common energy center of the pixel primitives is the simulated star point position. When the stray light is randomly distributed at the 9 pixel points, according to the centroid method, the star point energy center position (x, y) can be expressed as:

[0063]

[0064] Among them, b i is the grayscale of the i-th pixel primitive, x i is the horizontal coordinate of the center of the i-th pixel primitive, y i is the ordinate of the center of the i-th pixel primitive, x is the abscissa of the star point energy center position, and y is the ordinate of the star point energy center position.

[0065] Since the energy proportion of edge pixels has the greatest impact on the overall energy center of the star point in the 3×3 pixel primitive, the theoretical minimum value of the extinction ratio is calculated based on the premise that all stray light converges at the edge points. The grayscale expression of the optical engine extinction ratio k is:

[0066]

[0067] Among them, m i is the grayscale of the edge point, and k is the extinction ratio of the optical engine.

[0068] Furthermore, based on the centroid method, the theoretical value of the optical engine extinction ratio corresponding to the theoretical star point position simulation accuracy is calculated under the extreme condition, that is, when the stray light is concentrated at the edge of the star point, and it is used as the screening condition for the optical engine polarization balance film.

[0069] The preset coordinates (2.5, 2.5) are the coordinates of the simulated star point edge point position, and the coordinates of the star point energy center are (1.5, 1.5). The mathematical model expression of the extinction ratio and the star point position simulation accuracy is:

[0070]

[0071] Among them, m i is the grayscale of the edge point, θ is the simulation accuracy of the star point position, and f′ is the focal length of the optical system.

[0072] In some embodiments, the design goal of the optical engine is to work in the visible light band of 400nm to 600nm, the simulation accuracy of the star point position is better than 10, the focal length of the optical system used is f′=90, the single pixel size of the star map display device is 8.6μm, and the optical system parameters are shown in Table 1 below.

[0073] Table 1 Optical system parameters

[0074]

[0075]

[0076] Substituting f′=90mm and θ=10 into the mathematical model of extinction ratio and star point position simulation accuracy, we can get the edge point grayscale m i ≤1.02, take m i =1.02, and substituting it into the grayscale expression of the optical engine extinction ratio k, it can be obtained that the optical engine extinction ratio k should be better than 251:1.

[0077] Therefore, the screening condition for the optical engine polarization balance film is that the optical engine extinction ratio k should be better than 251: 1. In this way, the polarization film that meets the extinction ratio condition is screened out from the initial structure.

[0078] Step S3, establishing a polarization balance evaluation function for the optical engine film, enriching the selected polarization film structure through a genetic algorithm and optimizing it using a damped least squares method, and finally calculating the polarization balance evaluation function value of the optimized film and arranging it in ascending order.

[0079] Step S3-1, the polarization balance evaluation function of the optical engine film is established: since the polarization states of incident light with different fields of view and different aperture angles have different polarization states at different positions on the exit pupil plane after being acted upon by the optical engine film, a limited number of pupil sampling points (m, n) are selected on the exit pupil plane and the polarization states of the exit light at the corresponding positions are calculated to accurately determine the optimization of the polarization balance.

[0080] The polarization balance evaluation function expression of the optical engine film is:

[0081]

[0082] Where m and n represent the number of sampling points in the x-axis and y-axis directions of the pupil, respectively. is the transmittance attenuation corresponding to the current pupil sampling point (m, n), R(m, n) = δ(m, n) is the current value of the phase delay corresponding to the current pupil sampling point (m, n), ΔD(m, n) and ΔR(m, n) are tolerances, is the target value of transmittance attenuation, is the phase delay target value.

[0083] In some embodiments, m=n=9, weight y d =y r =1, ΔD(m,n)=ΔR(m,n)=2%.

[0084] Step S3-2, in order to reduce the number of times the initial structure is selected, the diversity of the films to be optimized should be increased, including: using the thickness of the screened polarizing film as an optimization variable, and using crossover, mutation and other operations in the genetic algorithm to enrich the number of optical engine films to 2H.

[0085] Specifically, a suitable initial structure of the optical engine film is selected according to the design index. The selected film is expressed as G|HLHLH|G, where G is the base glass, H is the high refractive index material, and L is the low refractive index material. Furthermore, H is made of ZnS with a refractive index of 2.36, L is made of Ag with a refractive index of 0.055, a central wavelength of 550nm, and a thickness of The thickness of the optical engine film is used as the optimization variable, and the number of films is enriched to 2H by using crossover and mutation operations in the genetic algorithm. Assuming that the position of the crossover point of the film to be optimized is 0.5α, the crossover operation is to use the selected crossover point as the boundary, and exchange the composition of the two films behind the crossover point. The crossover operation expression is:

[0086]

[0087] Among them, x i and x j are two random films, x q and x h These are the two new films generated after the crossover operation.

[0088] The mutation operation is a process that simulates gene mutation. The film thickness is assigned a value, and the assignment range is set to 3 to 5 times the minimum film thickness.

[0089] The polarization balance evaluation function values ​​corresponding to the 2H selected polarization films are calculated respectively and arranged in order from small to large. The first H films are selected as the secondary films to be optimized, and the film thickness is optimized using the damped least squares method.

[0090] Step S3-3, recording the optimized film structure, calculating the polarization balance evaluation function value corresponding to the optimized film and arranging them in ascending order.

[0091] Step S4, evaluating the optimized optical engine film according to the extinction ratio target value, and selecting the optimal optical engine film.

[0092] Specifically, the optimization result of step S3-3 is evaluated according to the extinction ratio target value obtained in step S2 as the screening condition of the optical engine polarization balance film. If the extinction ratio screening condition is met, the best film structure is recorded and selected. If the screening condition is not met, the initial film structure obtained in step S1 is replaced and optimized again.

[0093] In some examples, after optimization and screening, the composition of the polarization balancing film of the optical engine is shown in Table 2 below.

[0094] Material Refractive Index Optical Depth Glass 1.51 / ZnS 2.36 0.335 Ag 0.55 0.0018 ZnS 2.36 0.179 Ag 0.55 0.002 ZnS 2.36 0.421 Glass 1.51 /

[0095] After polarization balance optimization, the optical engine film transmittance and phase difference curves are as follows: Figure 2 When the incident light aperture angle is less than 8°, the maximum binomial attenuation is 0.0048, and the maximum phase delay is 0.34°. Compared with the traditional optical engine, the binomial attenuation and phase delay are reduced by 10.5% and 15.3%, respectively.

[0096] The extinction ratio ρ of the polarization-balanced optical engine is expressed by parameters such as Tp and Ts. The formula for the extinction ratio is:

[0097]

[0098] Wherein, ε is the extinction ratio of the polarizer in the optical engine, and ε is set to ε=2000:1.

[0099] It has been calculated that when the incident light aperture angle is less than 8°, the extinction ratio of the polarization-balanced optical engine is better than 472:1, which meets the requirement of the star point position simulation accuracy better than 10″ and the optical engine extinction ratio k better than 251:1.

[0100] like Figure 3 As shown, Figure 3 It represents the actual measured results of the star point position simulation accuracy after using the polarization balanced optical engine. Compared with the traditional optical engine, the test results show that the full field of view star point position simulation accuracy drops from 15.99″ to 9.76″, a decrease of 1.64 times.

[0101] Second implementation method:

[0102] like Figure 4 As shown, the second embodiment of the present invention provides an optical engine polarization balance optimization system, including: a derivation module 201, a modeling module 202, an optimization module 203, and a screening module 204.

[0103] Specifically, the derivation module 201 is used to establish the Jones matrix of the optical engine polarization film, derive the optimal analytical expression of the polarization parameters of the optical engine film, and use it as the optimization target, and at the same time select the optical engine polarization balance film close to the optimization target as the initial structure; the modeling module 202 is used to establish the extinction ratio and star point position simulation accuracy mathematical model, and obtain the extinction ratio target value according to the theoretical value of the star point position simulation accuracy, and use it as the screening condition of the optical engine polarization balance film, and screen out the polarization film that meets the extinction ratio condition from the initial structure; the optimization module 203 is used to establish the polarization balance evaluation function of the optical engine film, enrich the selected polarization film structure through the genetic algorithm and optimize it using the damped least squares method, and finally calculate the polarization balance evaluation function value of the optimized film and arrange it in ascending order; the screening module 204 is used to evaluate the optimized optical engine film according to the extinction ratio target value, and select the optimal optical engine film.

[0104] It is not difficult to find that this embodiment is a system embodiment corresponding to the first embodiment, and this embodiment can be implemented in conjunction with the first embodiment. The relevant technical details mentioned in the first embodiment are still valid in this embodiment, and in order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied in the first embodiment.

[0105] It is worth mentioning that all modules involved in this embodiment are logic modules. In practical applications, a logic unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. In addition, in order to highlight the innovative part of the present invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by the present invention, but this does not mean that there are no other units in this embodiment.

[0106] Third embodiment:

[0107] A third embodiment of the present invention provides a network side server, such as Figure 5 As shown, it includes at least one processor 301; and a memory 302 that is communicatively connected to the at least one processor 301; wherein the memory 302 stores commands that can be executed by at least one processor 301, and the instructions are executed by at least one processor 301, so that at least one processor 301 can execute the above-mentioned data processing method.

[0108] The memory 302 and the processor 301 are connected in a bus manner, and the bus may include any number of interconnected buses and bridges, and the bus connects various circuits of one or more processors 301 and the memory 302 together. The bus can also connect various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be one element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices on a transmission medium. The data processed by the processor 301 is transmitted on a wireless medium through an antenna, and further, the antenna also receives data and transmits the data to the processor 301.

[0109] The processor 301 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management and other control functions. The memory 302 can be used to store data used by the processor 301 when performing operations.

[0110] Fourth embodiment:

[0111] A fourth embodiment of the present invention provides a computer-readable storage medium storing a computer program, which implements the optical engine polarization balance optimization method in the first embodiment when executed by a processor.

[0112] That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0113] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for optimizing polarization balance of an optical engine, characterized in that: include: S1, establish the Jones matrix of the optical engine polarization film, derive the optimal analytical formula of the polarization parameters of the optical engine film, and use it as the optimization target, and select the optical engine polarization balance film close to the optimization target as the initial structure; S2, establishing a mathematical model of extinction ratio and star point position simulation accuracy, deriving an extinction ratio target value based on the theoretical value of the star point position simulation accuracy, using it as a screening condition for the polarization balance film of the optical engine, and screening out polarization films that meet the extinction ratio condition from the initial structure; S3, establishing a polarization balance evaluation function for the optical engine film, enriching the selected polarization film structure through a genetic algorithm and optimizing it using a damped least squares method, and finally calculating the polarization balance evaluation function value of the optimized film and arranging them in ascending order; S4, evaluating the optimized optical engine film according to the extinction ratio target value, and selecting the optimal optical engine film; The method of establishing the mathematical model of extinction ratio and star point position simulation accuracy includes: the grayscale expression of the optical engine extinction ratio k is: Among them, m i is the grayscale of the edge point, k is the extinction ratio of the optical engine; Based on the centroid method, the theoretical value of the optical engine extinction ratio corresponding to the theoretical star point position simulation accuracy is calculated under the extreme condition that the stray light is concentrated at the edge of the star point, and the theoretical value of the optical engine extinction ratio is used as the screening condition for the optical engine polarization balance film; The preset coordinates (2.5, 2.5) are the coordinates of the simulated star point edge point position, the star point energy center coordinates are (1.5, 1.5), and the mathematical model expression of the extinction ratio and the star point position simulation accuracy is: Among them, m i is the grayscale of the edge point, θ is the simulation accuracy of the star point position, and f′ is the focal length of the optical system.

2. The optical engine polarization balance optimization method according to claim 1, characterized in that: In S1, the optical engine polarization film Jones matrix is: Among them, i is an imaginary number, is the incident light aperture angle of the central field of view, T p is the transmittance of P light in the transmitted light field, T s is the transmittance of S light in the transmitted light field, Δ=(Δs+Δp) / 2 is the average phase, and δ=Δs-Δp is the phase difference.

3. The optical engine polarization balance optimization method according to claim 2, characterized in that: In S1, the optimal analytical formula for the polarization parameters of the optical engine film is: δ = 0 and (T p -T s ) / (T p +T s )=0.

4. The method for optimizing polarization balance of an optical engine according to claim 1, characterized in that: In S3, the polarization balance evaluation function expression of the optical engine film is: Where m and n represent the number of sampling points in the x-axis and y-axis directions of the pupil, respectively. is the transmittance attenuation corresponding to the current pupil sampling point (m, n), R(m, n) = δ(m, n) is the current value of the phase delay corresponding to the current pupil sampling point (m, n), ΔD(m, n) and ΔR(m, n) are tolerances, is the target value of phase delay, is the target value of transmittance attenuation, T p is the transmittance of P light in the transmitted light field, T s is the transmittance of S light in the transmitted light field, y d and r is the weight.

5. The method for optimizing polarization balance of an optical engine according to claim 4, characterized in that: In S3, in order to reduce the number of times the initial structure is selected, the diversity of the films to be optimized should be increased, including: using the thickness of the screened polarization film as an optimization variable, and using the crossover and mutation operations in the genetic algorithm to enrich the number of optical engine films to 2H.

6. The method for optimizing polarization balance of an optical engine according to claim 5, characterized in that: S3 also includes calculating the polarization balance evaluation function values ​​corresponding to the 2H screened polarization films respectively, arranging them in order from small to large, selecting the first H films as secondary films to be optimized, and optimizing the film thickness using the damped least squares method.

7. The method for optimizing polarization balance of an optical engine according to claim 6, characterized in that: S3 also includes recording the optimized film structure, calculating the polarization balance evaluation function value corresponding to the optimized film and arranging them in ascending order.

8. The method for optimizing polarization balance of an optical engine according to claim 7, characterized in that: In S4, the polarization balance evaluation function value corresponding to the optimized film is evaluated based on the extinction ratio target value obtained in step S2 as the screening condition of the optical engine polarization balance film. If the extinction ratio screening condition is met, the best film structure is recorded and selected. If the screening condition is not met, the initial film structure obtained in step S1 is replaced and optimized again.

9. An optical engine polarization balance optimization system, characterized in that: Applicable to the optical engine polarization balance optimization method described in claims 1-8, the optical engine polarization balance optimization system comprises: The derivation module is used to establish the Jones matrix of the optical engine polarization film, derive the optimal analytical expression of the polarization parameters of the optical engine film, and use it as the optimization target. At the same time, the optical engine polarization balance film close to the optimization target is selected as the initial structure; Modeling module, used to establish the mathematical model of extinction ratio and star point position simulation accuracy, obtain the extinction ratio target value according to the theoretical value of star point position simulation accuracy, use it as the screening condition of the polarization balance film of the optical engine, and screen out the polarization film that meets the extinction ratio condition from the initial structure; The optimization module is used to establish the polarization balance evaluation function of the optical engine film, enrich the selected polarization film structure through the genetic algorithm and optimize it using the damped least squares method, and finally calculate the polarization balance evaluation function value of the optimized film and arrange it in ascending order; The screening module is used to evaluate the optimized optical engine film according to the extinction ratio target value and select the optimal optical engine film.

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