Off-axis coaxial combined optical system design method based on asymmetric aberration compensation

Abstract

The application discloses a design method of an off-axis coaxial combined optical system based on asymmetric aberration compensation, and belongs to the technical field of optical system design. The method solves the problem that asymmetric aberration introduced by an off-axis part in the design of an off-axis coaxial combined optical system is difficult to be corrected compatibly with the rotationally symmetric aberration of a coaxial part. The optical system comprises an off-axis front group and a coaxial rear group. The design method is as follows: active compensation design of asymmetric aberration is performed on the off-axis front group, and an initial structure is built according to design requirements; the initial structure is subjected to field offset; an evaluation function of the off-axis front group for the compensation of asymmetric aberration about the optical axis is constructed; the asymmetric aberration of the off-axis front group is compensated and adjusted until the function value of the evaluation function is the minimum value. Correction design of the remaining rotationally symmetric aberration is performed on the coaxial rear group; the off-axis front group and the coaxial rear group are integrated and optimized, and the design is completed. The design method can be applied to the optimization of an existing off-axis coaxial combined optical system.

Description

Design Method for Off-Axis and Coaxial Joint Optical Systems Based on Asymmetric Aberration Compensation Technical Field

[0001] This invention belongs to the field of optical system design technology, and the optical system is an optical system applied in the field of optical detection. Background Technology

[0002] As space optics and remote sensing technologies place increasingly higher demands on the resolution, detection range, coverage, and operating band of optical systems, these systems are increasingly designed using a combination of reflection and transmission, or off-axis and coaxial approaches. Systems combining a front-group off-axis reflection with a rear-group coaxial transmission offer several advantages. Firstly, the off-axis reflection structure of the front group, with its lack of central obstruction and chromatic aberration, enables large aperture, wide spectrum, and a large field of view. Secondly, it can be combined with various coaxial transmission rear groups for multi-spectral imaging, allowing different relative apertures to be matched to each channel. This improves system performance while expanding the design space and freedom of optical systems.

[0003] However, the asymmetric aberrations introduced by the off-axis portion of the system, which are difficult to compensate for with the rotational symmetry aberrations of the coaxial portion, significantly increase the complexity of the system design and the difficulty of optimization. Traditional solutions often force the use of a large number of lenses to form an extremely complex rear group structure, and "force" correction by introducing aspherical or even diffractive surfaces. Although this method can solve the above problems, it brings new problems: not only does it lead to a huge system size and soaring costs, but it also causes the design optimization to get stuck in local solutions, resulting in poor stability and manufacturability of the entire optical system. Summary of the Invention

[0004] This invention solves the problem in existing off-axis and coaxial combined optical system designs where the asymmetric aberrations introduced by the off-axis portion are difficult to be compatible with and corrected for rotational symmetry aberrations in the coaxial portion.

[0005] The technical solution provided by this invention:

[0006] A design method for an off-axis and coaxial joint optical system based on asymmetric aberration compensation, wherein the optical system includes an off-axis front group and a coaxial rear group, the method comprising the following steps:

[0007] S1: Active compensation design for asymmetric aberrations in the off-axis anterior group, including:

[0008] S11: Construct the initial structure of the off-axis front assembly according to the design requirements of the optical system;

[0009] S12: The initial structure of the off-axis front group is biased in the field of view, and the principal ray at the center of the field of view after the field of view is biased is the optical axis of the optical system;

[0010] S13: Construct an evaluation function for asymmetric aberration compensation about the optical axis in the off-axis front group;

[0011] S14: Optimize the evaluation function to compensate and adjust the asymmetric aberrations of the off-axis anterior group until the function value of the evaluation function is minimized, thus completing the active compensation design of the off-axis anterior group;

[0012] S2: Design for correction of residual rotational symmetry aberrations in the coaxial rear group;

[0013] S3: Integrate and optimize the off-axis front group adjusted in S1 and the coaxial rear group obtained by the correction design in S2 to complete the design of the optical system.

[0014] Furthermore, in one embodiment of the present invention, in step S11, the initial structure of the off-axis front group is a field-biased off-axis reflection system.

[0015] Furthermore, in one embodiment of the present invention, in step S13, the evaluation function takes the initial structure as the analysis object, and the independent variables are the eccentricity and tilt of the optical surfaces of all optical elements in the initial structure.

[0016] Furthermore, in one embodiment of the present invention, when constructing the evaluation function in step S13, the coma field node positions are... Designed along the optical axis described in step S12, asymmetric compensation for coma is achieved; the image scattering dual-node is then implemented. and The midpoint position is designed on the optical axis described in step S12 to achieve asymmetric compensation for astigmatism.

[0017] Furthermore, in one embodiment of the present invention, the evaluation function in step S13 is:

[0018]

[0019] in: This indicates the amount of tilt introduced by the optical surface. The eccentricity introduced to the optical surface. This indicates the serial number of the optical surface of each optical element in the initial structure; To balance and optimize the weighting factors of the coma field node positions, To balance the weighting factor of the midpoint position of the two nodes in the scatter field, To balance the weighting factor of the distance between two nodes in the scatter field, To balance and optimize the wavefront aberration weighting factors of coma, To balance and optimize the wave aberrations of astigmatism; Location of coma field nodes The evaluation sub-function, For image field dual node and The evaluation sub-function for the midpoint position, For image field dual node and Distance evaluation subfunction, For wave aberration evaluation sub-functions of coma, This is a sub-function for evaluating wave aberrations in astigmatism.

[0020] Furthermore, in one embodiment of the present invention, the tilt amount... The range of values ​​for is:

[0021] ,

[0022] The eccentricity The range of values ​​for is:

[0023] ,

[0024] , , and The range of values ​​for constraining the eccentricity and tilt of the optical surface j is defined.

[0025] Furthermore, in one embodiment of the present invention, the various evaluation sub-functions are as follows:

[0026]

[0027] in: The optical axis position of the optical system. For optical surfaces The center offset vector of the aberration field caused by eccentricity and tilt. For optical surfaces The wave aberration coefficient of coma, For optical surfaces Astigmatic wave aberration coefficients.

[0028] Furthermore, the present invention also provides another technical solution:

[0029] A design system for an off-axis and coaxial combined optical system based on asymmetric aberration compensation, wherein the optical system includes an off-axis front group and a coaxial rear group, and the design system includes:

[0030] Off-axis anterior group active compensation module: Used for active compensation design of asymmetric aberrations in the off-axis anterior group. This module includes:

[0031] Initial structure building unit: used to build the initial structure of the off-axis front group according to the application requirements of the off-axis and coaxial combined optical system;

[0032] Field of view biasing unit: used to bias the field of view of the initial structure of the off-axis front group, wherein the principal ray at the center of the field of view after the field of view bias is the optical axis of the off-axis and coaxial combined optical system;

[0033] Evaluation function construction unit: used to construct the evaluation function for asymmetric aberration compensation about the optical axis in the off-axis front group;

[0034] Optimization and compensation unit: used to optimize the evaluation function, compensate and adjust the asymmetric aberrations of the off-axis front group until the function value of the evaluation function is minimized;

[0035] Coaxial rear group correction module: used for designing corrections for residual rotational symmetry aberrations in the coaxial rear group;

[0036] System integration and optimization module: used to integrate and optimize the off-axis front group designed by the off-axis front group active compensation module and the coaxial rear group designed by the coaxial rear group correction module.

[0037] Furthermore, the present invention also provides another technical solution: a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of any of the design methods described in the present invention.

[0038] Furthermore, the present invention also provides another technical solution: a computer-readable storage medium having a computer program / instructions stored thereon, which, when executed by a processor, implements the steps of any of the design methods described in the present invention.

[0039] Furthermore, the present invention also provides another technical solution: a computer program product, including computer instructions, which, when executed by a processor, implement the steps of any of the design methods described in the present invention.

[0040] The off-axis and coaxial joint optical system design method based on asymmetric aberration compensation described in this invention can actively control and compensate for asymmetric aberrations, enabling mutual compensation and correction between the off-axis asymmetric aberrations and the coaxial rotational symmetry aberrations. The specific advantages compared to existing technologies are as follows:

[0041] To address the issue of the difficulty in compatibly correcting the asymmetric aberrations introduced by the off-axis component in a combined off-axis and coaxial optical system with the rotational symmetry aberrations of the coaxial component, an active compensation design for asymmetric aberrations is implemented in the off-axis front group. The coaxial rear group only needs to handle the classical rotational symmetry aberrations, reducing the design difficulty of the coaxial rear group. This not only resolves the contradiction of incompatibility between aberration systems in the design of combined off-axis and coaxial systems, but also fundamentally and significantly reduces the design complexity of the combined off-axis and coaxial optical system.

[0042] This invention combines an off-axis reflection system with a coaxial transmission system, enabling the final integrated system to achieve large aperture, wide spectrum, and large field of view by utilizing the unobstructed and chromatic aberration-free characteristics of the off-axis reflection structure; and to perform multi-spectral imaging by matching different coaxial transmission systems, allowing each channel to be matched with different relative apertures. This improves system performance while expanding the design space and degrees of freedom of the optical system.

[0043] The off-axis and coaxial combined optical system obtained by the off-axis and coaxial combined optical system design method described in this invention is applicable to the field of optical detection.

[0044] The design method described in this invention is applicable to the design of optical systems with specific application requirements, and is also applicable to the optimization and improvement of existing off-axis and coaxial combined optical systems. Attached Figure Description

[0045] Figure 1 is a flowchart illustrating the design method of an off-axis and coaxial combined optical system based on asymmetric aberration compensation as described in Embodiment 1.

[0046] Figure 2 is a schematic diagram of the initial structure of the off-axis front group in the optical system.

[0047] Figure 3 shows the coma field of the initial structure shown in Figure 2.

[0048] Figure 4 shows the astigmatism field of the initial structure shown in Figure 2.

[0049] Figure 5 is a schematic diagram of the off-axis front group after the field of view of the initial structure shown in Figure 2 is offset.

[0050] Figure 6 is a schematic diagram of the optical path after asymmetric aberration compensation for the off-axis front group shown in Figure 5.

[0051] Figure 7 shows the coma field of the off-axis front group as shown in Figure 6.

[0052] Figure 8 shows the astigmatism field of the off-axis front group as shown in Figure 6.

[0053] Figure 9 is a schematic diagram of the optical path of the off-axis and coaxial combined optical system obtained by the design method described in Embodiment 1.

[0054] Figure 10 shows the MTF of the off-axis and coaxial combined optical system shown in Figure 9 in the range of 0.486 μm to 0.656 μm.

[0055] Figure 11 shows the MTF of the off-axis and coaxial combined optical system shown in Figure 9 in the range of 3 μm to 5 μm.

[0056] Figure labels: Node 1 of coma field, Node 2 of image divergence field, Principal ray of 6° field of view in the meridional direction, 3, 8° field of view, 4, 6° field of view, 5, 4° field of view, 6, Location of coma field nodes. 7. Like the position of one node in a two-node system in a game ending. 8. The position of the other node in a two-node system for a closed-loop game. 9. The primary mirror of the off-axis front group; 10. The secondary mirror of the primary mirror of the off-axis front group; 11. The third mirror of the off-axis front group; 12. The lens group of the visible light channel of the coaxial rear group consists of three lenses 13, 14 and 15 connected in series; the lens group of the infrared channel of the coaxial rear group consists of three lenses 16, 17 and 18; and the beam splitter element 19. Detailed Implementation

[0057] To facilitate understanding of the technical solutions claimed in this invention, the following specific embodiments are provided in conjunction with the accompanying drawings. These embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of this application. Those skilled in the art can make reasonable adjustments to the embodiments given in the following specific embodiments based on their general knowledge in the art to adapt them to specific application scenarios.

[0058] Implementation Method 1, see Figure 1 for illustration. This implementation method describes a design method for an off-axis and coaxial combined optical system based on asymmetric aberration compensation. The optical system includes an off-axis front group and a coaxial rear group. The method includes the following steps:

[0059] S1: Active compensation design for asymmetric aberrations in the off-axis anterior group, including:

[0060] S11: Construct the initial structure of the off-axis front assembly according to the design requirements of the optical system;

[0061] S12: The initial structure of the off-axis front group is biased in the field of view, and the principal ray at the center of the field of view after the field of view is biased is the optical axis of the optical system;

[0062] S13: Construct an evaluation function for asymmetric aberration compensation about the optical axis in the off-axis front group;

[0063] S14: Optimize the evaluation function to compensate and adjust the asymmetric aberrations of the off-axis anterior group until the function value of the evaluation function is minimized, thus completing the active compensation design of the off-axis anterior group;

[0064] S2: Design for correction of residual rotational symmetry aberrations in the coaxial rear group;

[0065] S3: Integrate and optimize the off-axis front group adjusted in S1 and the coaxial rear group obtained by the correction design in S2 to complete the design of the optical system.

[0066] In this embodiment, the initial structure of the off-axis front group described in step S11 is a conventional structure in existing off-axis and coaxial combined optical systems. For example, it can be a field-biased off-axis reflection system.

[0067] In this embodiment, the evaluation function constructed in step 13 takes the initial structure as the analysis object, and the independent variables are the eccentricity and tilt of the optical surfaces of all optical elements in the initial structure.

[0068] The evaluation function described in this embodiment is designed based on the compensation and design goals to be achieved. During the construction of the evaluation function, the coma field node positions are considered. Designed along the optical axis described in step S12, asymmetric compensation for coma is achieved; the image scattering dual-node is then implemented. and The midpoint position is designed on the optical axis described in step S12, and the astigmatism dual-node is made... and The distance should be minimized to achieve asymmetric compensation for astigmatism.

[0069] In this embodiment, the image scattering dual-node is to be and The distance is kept as small as possible to compensate for asymmetric aberrations. As shown in Figure 8, the astigmatic field of the off-axis front group will be distributed in an elliptical shape, and the astigmatic field has two nodes. and Located at the two foci of the ellipse, therefore, to compensate for asymmetric astigmatism, it is necessary not only to add two nodes to the astigmatism field... and The midpoint position is designed on the optical axis as described in step S12, and the image scattering dual-node is also required. and The distance should be as small as possible; for example, it can be like a two-node scattering field. and The distance is less than half the field of view of the astigmatic field of the off-axis front group. Specifically: when the two nodes of the astigmatic field are in the field of view in the Y direction, then the two nodes of the astigmatic field are made... and The distance is less than half the length of the astigmatic field of view in the Y direction of the off-axis front group, where the length of the Y-direction field of view refers to the axial length of the astigmatic field in the Y direction; when the two nodes of the astigmatic field are in the X-direction field of view, the astigmatic field two nodes... and The distance is less than half the length of the astigmatic field of view in the X direction of the off-axis front group, where the length of the X-direction field of view refers to the axial length of the astigmatic field in the X direction; thus, when the off-axis front group and the coaxial rear group are integrated and optimized, the astigmatic fields of the front and rear groups can be efficiently compensated and corrected for each other.

[0070] In this embodiment, the evaluation function can be:

[0071] ,

[0072] in: Indicates optical surface The amount of tilt introduced. For optical surfaces The introduced eccentricity, This indicates the index of each optical surface in the initial structure; in this embodiment, the weight factors in each sub-function are designed to balance the priorities of different optimization objectives. To balance and optimize the weighting factors of the coma field node positions, To balance the weighting factor of the midpoint position of the two nodes in the scatter field, To balance the weighting factor of the distance between two nodes in the scatter field, To balance and optimize the wavefront aberration weighting factors of coma, To balance and optimize the weighting factors of wave aberrations in astigmatism, Location of coma field nodes The evaluation sub-function, For image field dual node and The evaluation sub-function for the midpoint position, For the distance evaluation subfunction of the two nodes in the image field, For wave aberration evaluation sub-functions of coma, This is a sub-function for evaluating wave aberrations in astigmatism.

[0073] In this embodiment, the range of values ​​for eccentricity and tilt is preferably limited, wherein: tilt The range of values ​​for is:

[0074] ,

[0075] The eccentricity The range of values ​​for is:

[0076] ,

[0077] , , and For optical surfaces The range of values ​​for eccentricity and tilt are constrained.

[0078] In practical applications, the boundaries of the above value range , , and The design can be based on the application performance requirements of the optical system. For example, the design requirements of the third-order aberration coefficient of the off-axis front group should be considered, and the problem of components blocking imaging light should be avoided when the optical surface is eccentric or tilted.

[0079] In this embodiment, the range of values ​​for eccentricity and tilt is limited, thereby ensuring that the eccentricity and tilt introduced by the reflective surface are small and will not affect the third-order aberration coefficient of the off-axis front group. At the same time, it avoids the problem of the optical surface blocking the imaging light when it is eccentric and tilted.

[0080] The evaluation sub-functions are as follows:

[0081]

[0082] in: The optical axis position of the optical system. For optical surfaces The center offset vector of the aberration field caused by eccentricity and tilt. For optical surfaces The wave aberration coefficient of coma, For optical surfaces Astigmatic wave aberration coefficients.

[0083] The above evaluation sub-function enables the design of wavelet aberration magnitude, thereby preventing image quality degradation.

[0084] Implementation Method Two: This implementation method is an example illustration of the off-axis and coaxial combined optical system design method based on asymmetric aberration compensation described in Implementation Method One.

[0085] In this embodiment, the initial structure described in step S11 adopts the structure of the field-of-view offset type off-axis reflection system shown in Figure 2. The field of view range of this structure is -8° to 8° in the meridional direction and -4° to 4° in the sagittal direction.

[0086] Figure 3 shows the coma field of the initial structure shown in Figure 2, where 1 is a node of the coma field; Figure 4 shows the astigmatic field of the initial structure shown in Figure 2, where 2 is a node of the astigmatic field; Figure 5 is a schematic diagram of the off-axis front group after the field of view of the initial structure shown in Figure 2 is offset in this embodiment, with the field of view offset being 6° in the meridional direction. The field of view range of the off-axis front group after the field of view offset is: 4°~8° in the meridional direction and -4°~4° in the sagittal direction; 3 in Figure 5 is the principal ray of the 6° meridional field of view, which is defined as the optical axis of the off-axis and coaxial combined optical system. Therefore, the field of view of the initial structure is shown in Figure 5, where reference numeral 4 in Figure 5 represents an 8-degree field of view, reference numeral 5 represents a 6-degree field of view, and reference numeral 6 represents a 4-degree field of view.

[0087] As can be seen from the coma field distribution in the initial structure shown in Figure 3 and the astigmatic field distribution in Figure 4, the coma and astigmatic field nodes of the initial structure are both located at the 0° field of view, and both the coma and astigmatic fields are rotationally symmetric about the 0° field of view. However, their rotational symmetry about the 6° field of view, i.e., the optical axis of the off-axis and coaxial combined optical system in Figure 5, is poor. Based on the above figures, it can be concluded that because the initial structure of the off-axis front group did not compensate for asymmetric aberrations, the aberration field of the off-axis front group has poor rotational symmetry about the optical axis of the off-axis and coaxial combined optical system. The coaxial transmission system of the rear group is designed based on the assumption of rotational symmetry, and its ability to correct asymmetric aberrations is extremely limited and inefficient. At this time, the aberrations between the front and rear groups cannot be effectively compensated for each other, forcing the use of a large number of lenses to form an extremely complex rear group structure, which greatly increases the design difficulty and complexity of the rear group.

[0088] In summary, after compensating and adjusting the initial structure using steps S13 and S14, the asymmetric aberrations were compensated. At this point, the off-axis front group structure is shown in Figure 6.

[0089] The coma field of the off-axis pre-assembly structure shown in Figure 6 is illustrated in Figure 7. The coma field node positions are indicated by mark 7 in Figure 7. Located at 5.9° in the meridional field of view; the astigmatic field of the off-axis front group structure is shown in Figure 8, where markings 8 and 9 are the two nodes of the astigmatic field. and The midpoint of the two nodes is located at 6.1° in the meridional field of view, and the distance between the two nodes is 3.6°.

[0090] Comparing Figures 3 and 7, it can be determined that the coma field of the off-axis front group, which compensates for asymmetric aberrations, is rotationally symmetric about the optical axis of the off-axis coaxial combined optical system in Figure 5 with respect to a 6° field of view. Comparing Figures 4 and 8, it can be determined that the astigmatic field of the off-axis front group, which compensates for asymmetric aberrations, has good rotational symmetry about the optical axis of the off-axis coaxial combined optical system in Figure 5 with respect to a 6° field of view. Therefore, it can be proven that the aberration field of the off-axis front group structure shown in Figure 6, which compensates for asymmetric aberrations, has good rotational symmetry about the optical axis and can perform efficient mutual compensation and correction with the aberration field of the coaxial rear group. This step, by actively compensating for asymmetric aberrations in the off-axis front group, allows the rear group to only handle conventional rotationally symmetric aberrations. Therefore, a simple and classic coaxial transmission structure can be adopted, which not only reduces the design difficulty and complexity of the rear group but also makes it easier to achieve multi-band imaging and independent optimization of the relative aperture of each channel.

[0091] In this embodiment, the anterior structural parameters that compensate for asymmetric aberrations are shown in Table 1.

[0092] Table 1

[0093]

[0094] By actively compensating for asymmetric aberrations in the off-axis front group, the coaxial rear group only needs to handle classic rotational symmetry aberrations. Therefore, in step S2 of this embodiment, the remaining rotational symmetry aberrations in the coaxial rear group can be corrected, which reduces the design difficulty of the coaxial rear group. This not only solves the contradiction of incompatibility between aberration systems in the design of off-axis and coaxial combined systems, but also fundamentally and significantly reduces the design complexity of the off-axis and coaxial combined optical system.

[0095] In practical design, to achieve multi-spectral imaging, the coaxial rear array needs to be matched with different spectral ranges and relative aperture requirements. This design can be achieved using existing technologies.

[0096] The above-mentioned correction design for the coaxial rear group is based on the off-axis front group structure of the active compensation design for the asymmetric aberration. That is, the off-axis front group with the completed compensation design is connected to the coaxial rear group, and the remaining rotational symmetry phase difference of the coaxial rear group is corrected using step S2. After the correction design is completed, the off-axis front group and the coaxial rear group are integrated and optimized. The optical path structure of the off-axis and coaxial joint optical system is shown in Figure 9.

[0097] The optical system shown in Figure 9, when in operation, first converges the light beam through the off-axis reflection system of the front group, and then enters the coaxial transmission system of the rear group to complete the final imaging. The specific optical path of the imaging process is as follows: the incident light beam is reflected by the primary mirror 10 of the off-axis front group to the secondary mirror 11 of the primary mirror of the off-axis front group, and then reflected by the secondary mirror 11 to the third mirror 12 of the off-axis front group. The light beam reflected by the third mirror 12 is incident on the beam splitter 19. The visible light reflected by the beam splitter 19 is converged and imaged by the lens group of the visible light channel of the coaxial rear group (which consists of three lenses 13, 14 and 15 connected in series). The infrared light transmitted by the beam splitter 19 is converged and imaged by the lens group of the infrared channel of the coaxial rear group (which consists of three lenses 16, 17 and 18 connected in series).

[0098] Figure 10 shows the modulation transfer function (MTF) of the off-axis coaxial combined optical system shown in Figure 9 in the range of 0.486 μm to 0.656 μm. According to this figure, it can be determined that in this band, the modulation transfer function (MTF) of the off-axis coaxial combined optical system still maintains high imaging quality at a spatial frequency of 50 lp / mm. Its MTF value is greater than 0.7, indicating that the system has good resolution and image quality in this spectral band.

[0099] Figure 11 shows the modulation transfer function (MTF) of the off-axis coaxial combined optical system shown in Figure 9 in the 3μm–5μm range. Based on this figure, it can be determined that in this band, the MTF of the off-axis coaxial combined optical system at a spatial frequency of 33 lp / mm is greater than 0.3, indicating that the system still possesses effective imaging capability in the mid-infrared spectral band, meeting the optical detection requirements of this band.

[0100] The performance indicators of the off-axis and coaxial combined optical system obtained in this embodiment are shown in Table 2.

[0101] Table 2

[0102]

[0103] In this embodiment, an off-axis reflection system is used as the off-axis front group to process the light beam, achieving the characteristics of no central obstruction and no chromatic aberration, thus enabling a large aperture, wide spectrum, and large field of view. A coaxial transmission system is used as the off-axis rear group, combined with the preceding off-axis front group, allowing for multi-spectral imaging by matching different coaxial transmission systems, and permitting different relative apertures for each channel. The combination of these two systems improves the overall performance of the optical system while expanding its design space and degrees of freedom.

Claims

1. A design method for an off-axis and coaxial combined optical system based on asymmetric aberration compensation, wherein the optical system comprises an off-axis front group and a coaxial rear group, characterized in that, The method includes the following steps: S1: Active compensation design for asymmetric aberrations of the off-axis front group, including: S11: Constructing the initial structure of the off-axis front group according to the design requirements of the optical system; S12: Offsetting the field of view of the initial structure of the off-axis front group, wherein the principal ray at the center of the field of view after the field of view offset is the optical axis of the optical system; S13: Constructing an evaluation function for asymmetric aberration compensation about the optical axis in the off-axis front group; S14: Optimizing the evaluation function to compensate and adjust the asymmetric aberrations of the off-axis front group until the function value of the evaluation function is minimized, thus completing the active compensation design of the off-axis front group; S2: Correction design for residual rotational symmetry aberrations of the coaxial rear group; S3: Integrating and optimizing the off-axis front group adjusted in S1 and the coaxial rear group obtained by the correction design in S2, thus completing the design of the optical system.

2. The design method for an off-axis and coaxial combined optical system according to claim 1, characterized in that, In step S11, the initial structure of the off-axis front group is a field-biased off-axis reflection system.

3. The design method for an off-axis and coaxial combined optical system according to claim 1, characterized in that, In step S13, the evaluation function takes the initial structure as the analysis object, and the independent variables are the eccentricity and tilt of the optical surfaces of all optical elements in the initial structure.

4. The design method for an off-axis and coaxial combined optical system according to claim 1, characterized in that, When constructing the evaluation function in step S13, the coma field node positions are... Designed along the optical axis described in step S12, asymmetric compensation for coma is achieved; the image scattering dual-node is then implemented. and The midpoint position is designed on the optical axis described in step S12 to achieve asymmetric compensation for astigmatism.

5. The design method for an off-axis and coaxial combined optical system according to claim 3, characterized in that, The evaluation function mentioned in step S13 is: ,in: Indicates optical surface The amount of tilt introduced. For optical surfaces The introduced eccentricity, Indicates the serial number of the optical surface of each optical element in the initial structure; To balance and optimize the weighting factors of the coma field node positions, To balance the weighting factor of the midpoint position of the two nodes in the scatter field, To balance the weighting factor of the distance between two nodes in the scatter field, To balance and optimize the wavefront aberration weighting factors of coma, To balance and optimize the wave aberrations of astigmatism; Location of coma field nodes The evaluation sub-function, For image field dual node and The evaluation sub-function for the midpoint position, For the distance evaluation subfunction of the two nodes in the image field, For wave aberration evaluation sub-functions of coma, This is a sub-function for evaluating wave aberrations in astigmatism.

6. The design method for an off-axis and coaxial combined optical system according to claim 5, characterized in that, The tilt amount The range of values ​​for is: The eccentricity The range of values ​​for is: ， 、 、 and For optical surfaces The range of values ​​for eccentricity and tilt are constrained.

7. The design method for an off-axis and coaxial combined optical system according to claim 5, characterized in that, The evaluation sub-functions are as follows: in: The optical axis position of the optical system. For optical surfaces The center offset vector of the aberration field caused by eccentricity and tilt. For optical surfaces The wave aberration coefficient of coma, For optical surfaces Astigmatic wave aberration coefficients.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes a computer program to implement the steps of the design method according to any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the design method according to any one of claims 1-7.

10. A computer program product comprising computer instructions, characterized in that, When executed by a processor, the computer instructions implement the steps of the design method according to any one of claims 1-7.

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