Design method of compensation device for complex surface optical element and compensation detection device

Abstract

The present invention belongs to the field of optical detection technology, and particularly relates to a design method for a compensation device of a complex curved optical element and a compensation detection device. The method includes: S1: representing the height offset by a linear combination of a finite number of standard Zernike circular polynomials to obtain the aberration data to be compensated for the complex curved optical element to be measured; S2: obtaining the maximum amplitudes of various spatial light modulators in different Zernike aberration modes; S3: based on the aberration data to be compensated for the complex curved optical element to be measured and the maximum amplitudes of various spatial light modulators in different Zernike aberration modes, selecting the spatial light modulators participating in compensation in the compensation device; S4: loading grayscale images corresponding to the aberration types in the spatial modulators selected in step S3, and applying different voltages to the selected spatial light modulators to complete the design of the compensation device. The present invention greatly improves the versatility on the basis of the original high precision of interference compensation detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical detection, and particularly relates to a design method for a compensation device and a compensation detection device for a complex-curved optical element. Background Technique

[0002] Complex-curved optical elements have brought revolutionary progress to optical systems due to their relatively flexible design freedom. Compared with ordinary spherical optical elements, complex-curved optical elements can correct various aberrations of optical systems more efficiently. Sometimes, only one lens can achieve the aberration correction effect of several spherical lenses, which is beneficial to the compactification and lightweight of optical systems. Thanks to these advantages, complex-curved optical elements have been adopted in many fields, greatly promoting the development of aerospace, national defense, and high-tech civilian industries. However, due to the diverse types, different shapes, and inconsistent surface shape accuracy requirements in each processing stage of complex-curved optical elements, it poses great challenges to the surface shape detection of complex-curved optical elements. The surface shape detection technology of complex-curved optical elements has become the main bottleneck restricting the further development of high-end optical systems.

[0003] The detection methods for complex-curved optical elements can be divided into non-interference detection methods and interference detection methods. Non-interference detection methods are a general term for a class of detection methods that do not use the interference principle to detect the surface shape of the optical surface to be measured. For example: profilometer method and laser tracker method, etc. Non-interference detection methods generally have good versatility, but the surface shape detection accuracy is limited. The surface shape detection accuracy is generally between the micron and sub-micron levels, and it is mostly used for the detection in the milling, grinding, and rough polishing stages during the processing of complex-curved optical elements. Interference detection methods are a class of detection methods that use the principle of light wave interference to detect the surface shape of the optical surface to be measured. For example: computer-generated hologram method and multi-wavelength interference method, etc. Because of its nanometer-level detection accuracy, currently, interference detection methods are more common in the surface shape detection of the fine polishing stage of complex-curved optical elements. The core of using interference detection methods to detect complex-curved optical elements is to solve the problem of over-dense interference fringes caused by the large deviation between the complex-curved optical element and the reference surface. The most commonly used method is to design different compensators (such as computer-generated hologram plates) for different complex-curved optical elements. However, due to the high processing cost and difficulty of traditional compensators, when there are a large number of complex-curved optical elements in an optical system, it is often necessary to process different compensators for each different optical surface to be measured. Therefore, using compensators to detect complex-curved optical elements has problems of poor versatility, long detection cycle, and high cost. Therefore, the need for an interference detection method that can achieve high-versatility aberration compensation for different complex-curved optical elements in surface shape detection is becoming more and more urgent.

[0004] To solve the above contradictions, relevant research has been carried out by scholars at home and abroad in recent years. However, the above research generally uses a single compensator (such as a deformable mirror or a spatial light modulator) to compensate for the aberrations of complex curved optical elements. Its compensation ability is limited, and using a single compensator requires compensating for all primary aberrations at one time, which will further compress the compensation ability of the adaptive compensator for a single aberration, making it difficult to measure complex curved optical elements with a large single aberration to be measured. Summary of the Invention

[0005] In view of this, the present invention aims to provide a design method for a compensation device for complex curved optical elements and a compensation detection device to solve the problems that the existing technology has limited compensation ability for compensating the aberrations of complex curved optical elements and it is difficult to measure complex curved optical elements with a large single aberration to be measured. On the basis of the original high precision of interference compensation detection, the present invention greatly improves the versatility and helps to further realize the detection of complex curved optical elements with a large deviation.

[0006] To achieve the above object, the technical solution of the present invention is realized as follows:

[0007] A design method for a compensation device for complex curved optical elements, the compensation device includes not less than 1 spatial light modulator, and specifically includes the following steps:

[0008] S1: Calculate the sagittal height offset between the complex curved optical element to be measured and the ideal spherical mirror, and use the linear combination of finite-term standard Zernike circular polynomials to characterize the sagittal height offset, and obtain the aberration data to be compensated for the complex curved optical element to be measured;

[0009] S2: Determine the quantization level, and calculate the maximum amplitude of each type of spatial light modulator at the same quantization level in different Zernike aberration modes;

[0010] S3: Based on the aberration data to be compensated for the complex curved optical element to be measured and the maximum amplitude of each type of spatial light modulator in different Zernike aberration modes, select the types and quantities of spatial light modulators participating in the compensation in the compensation device;

[0011] S4: Load the grayscale image corresponding to the aberration type in each spatial modulator selected in step S3, and apply different voltages to the selected spatial modulators to complete the design of the compensation device.

[0012] Furthermore, in step S1, the vertex curvature radius value of the complex curved optical element to be measured is the same as the vertex curvature radius value of the ideal spherical mirror; the aberration data to be compensated includes tilt compensation value, defocus compensation value, astigmatism compensation value, coma compensation value, and spherical aberration compensation value.

[0013] Further, in step S1, the sag offset characterized by the linear combination of a finite number of standard Zernike circular polynomials has the following expression:

[0014] ;

[0015] wherein, is the i-th Zernike coefficient, is the i-th Zernike polynomial, is the radial coordinate, is the angular coordinate, n is the upper bound, Z0 is the translation, Z1 is the x-axis tilt, Z2 is the y-axis tilt, Z3 is the defocus, Z4 is the astigmatism at 0 degrees and defocus, Z5 is the astigmatism at 45 degrees and defocus, Z6 is the coma and x-axis tilt, Z7 is the coma and y-axis tilt, Z8 is the spherical aberration and defocus.

[0016] Further, in step S2, the Zernike aberration modes include tilt, defocus, astigmatism, coma, and spherical aberration.

[0017] A compensation detection device for a complex surface optical element includes an interferometer and a beam shrinking system, a polarizer, a compensation device for the complex surface optical element, and a standard spherical lens sequentially arranged along the beam emission direction of the interferometer. The beam emitted by the interferometer is converted into a measurement wavefront through the beam shrinking system, the polarizer, and the compensation device for the complex surface optical element. After the measurement wavefront is incident on the complex surface optical element to be measured for reflection through the standard spherical lens, it returns along the original path to the interferometer to form interference fringes containing the surface shape information of the complex surface optical element to be measured, thereby realizing the compensation detection of the complex surface optical element to be measured.

[0018] Further, the beam shrinking system shapes the beam emitted by the interferometer, the polarizer converts the shaped beam into linearly polarized light, and the linearly polarized light is converted into a measurement wavefront through the compensation device for the complex surface optical element.

[0019] Further, the standard spherical lens is used to converge the measurement wavefront.

[0020] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0021] (1) The compensation device design method and the compensation detection device for the complex surface optical element of the present invention can effectively expand the versatility of using the interference detection method to detect complex surface optical elements, improve the applicability of detecting complex surface optical elements with a large deviation amount, and improve the detection efficiency. The present invention is of great significance for the processing and application of complex surface optical elements.

[0022] (2)The design method and compensation detection device for the compensation device of complex surface optical elements of the present invention. The present invention proposes a method for compensating and detecting complex surface optical elements using multiple spatial light modulators (SLMs) (with universality). The deviation between the complex surface optical element and the sphere closest to it is fitted with Zernike polynomials and assigned to multiple spatial light modulators (SLMs) for compensation, doubling its aberration compensation ability. Based on the original high precision of interference compensation detection, the present invention greatly improves universality, which helps to further realize the detection of complex surface optical elements with large deviations.

[0023] (3)The design method and compensation detection device for the compensation device of complex surface optical elements of the present invention have stronger universality compared with traditional compensation detection methods, saving the time cost of "one-to-one" customized compensators by the computer-generated holography method. Compared with the method of using a single programmable compensator for interference detection, the present invention conducts the distribution compensation planning of the amount to be compensated for the complex surface optical element to be measured in advance, improving the utilization efficiency of the compensator. Its compensation range is the superposition of the compensation ranges of multiple compensators. Through the design of the compensation device for complex surface optical elements, the problem of insufficient compensation amount of a single compensator is effectively solved, saving the cost of customizing expensive high-end spatial light modulators for extreme detection requirements, and greatly improving the applicability of the programmable compensator for compensating and detecting complex surface optical elements with large deviations. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0025] Figure 1 It is a schematic flow chart of the design method of the compensation device for complex surface optical elements according to the embodiment of the present invention;

[0026] Figure 2 It is a schematic structural diagram of the compensation detection device for complex surface optical elements according to the embodiment of the present invention;

[0027] Figure 3 It is a schematic structural diagram of the reflective spatial light modulator according to the embodiment of the present invention;

[0028] Figure 4 It is a result diagram of the average amplitude of the Zernike aberration that can be generated by the spatial light modulator 4-1 according to the embodiment of the present invention when the set quantization level is 8;

[0029] Figure 5 (a) is a schematic structural diagram of the multi-reflective compensation device according to the embodiment of the present invention;

[0030] Figure 5(b) is a schematic structural diagram of the transmission and reflection combined compensation device according to the embodiment of the present invention;

[0031] Figure 5(c) is a schematic structural diagram of the multi-transmission compensation device according to the embodiment of the present invention.

[0032] Explanation of reference numerals:

[0033] 1. Interferometer; 2. Beam reducing system; 3. Polarizer; 4. Compensation device; 5. Standard spherical lens; 6. Complex curved optical element to be measured; 7. Glass plate; 8. Conductive electrode; 9. Alignment layer; 10. Liquid crystal layer; 11. Reflecting mirror; 12. Control electrode; 13. Silicon substrate; 4-1. Spatial light modulator; 4-1-1. Reflective spatial light modulator; 4-1-2. Transmissive spatial light modulator. Specific embodiments

[0034] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0035] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0037] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0038] The present invention will be described in detail below with reference to the drawings and in combination with embodiments.

[0039] As Figure 1 shown, the present invention proposes a design method for a compensation device for a complex curved surface optical element. The compensation device 4 includes not less than 1 spatial light modulator 4-1, and specifically includes the following steps: S1: Calculate the sag height offset between the complex curved surface optical element 6 to be measured and the ideal spherical mirror, and use the linear combination of a finite number of standard Zernike circular polynomials to represent the sag height offset, so as to obtain the aberration data to be compensated of the complex curved surface optical element 6 to be measured; S2: Determine the quantization level, and calculate the maximum amplitude of each type of spatial light modulator 4-1 at the same quantization level under different Zernike aberration modes; S3: Based on the aberration data to be compensated of the complex curved surface optical element 6 to be measured and the maximum amplitude of each type of spatial light modulator 4-1 under different Zernike aberration modes, select the types and quantities of the spatial light modulators 4-1 participating in the compensation in the compensation device 4; S4: Load a grayscale image corresponding to the aberration type in each of the spatial modulators selected in step S3, and apply different voltages to the selected spatial modulators to complete the design of the compensation device 4.

[0040] It should be noted that in view of the existing surface shape detection requirements of complex curved surface optical elements, the present invention proposes a method for universal compensation detection of complex curved surface optical elements using multiple SLMs. This method can realize high-universal detection of complex curved surface optical elements with large deviation amounts based on multiple SLMs. In addition, the quantization level is defined as the number of bits used to record the binary values of the colors of digital images in the spatial light modulator 4-1. The larger this index, the higher the modulation accuracy, and the quantization level is set according to the accuracy required by the user.

[0041] In some embodiments, in step S1, the vertex curvature radius value of the complex curved surface optical element 6 to be measured is the same as the vertex curvature radius value of the ideal spherical mirror; the aberration data to be compensated includes tilt compensation value, defocus compensation value, astigmatism compensation value, coma compensation value, and spherical aberration compensation value.

[0042] In some embodiments, in step S1, the sag height offset represented by the linear combination of a finite number of standard Zernike circular polynomials The expression is:

[0043] ;

[0044] Wherein, is the i-th Zernike coefficient, is the i-th Zernike polynomial, is the radial coordinate, is the angular coordinate, n is the upper bound, and when n = 8, Z0 is translation, Z1 is x-axis tilt, Z2 is y-axis tilt, Z3 is defocus, Z4 is astigmatism at 0 degrees and defocus; Z5 is astigmatism at 45 degrees and defocus; Z6 is coma and x-axis tilt; Z7 is coma and y-axis tilt; Z8 is spherical aberration and defocus.

[0045] In some embodiments, in step S2, the Zernike aberration modes include tilt, defocus, astigmatism, coma, and spherical aberration.

[0046] As Figure 2 shown, the present invention provides a compensation detection device for a complex surface optical element, including an interferometer 1 and a beam reduction system 2, a polarizer 3, a compensation device 4 for the complex surface optical element, and a standard spherical lens 5 arranged in sequence along the beam output direction of the interferometer 1. The beam emitted by the interferometer 1 is converted into a measurement wavefront by the beam reduction system 2, the polarizer 3, and the compensation device 4 for the complex surface optical element. After the measurement wavefront is incident on the complex surface optical element 6 to be measured through the standard spherical lens 5 for reflection, it returns along the original path to the interferometer 1 to form interference fringes containing the surface shape information of the complex surface optical element 6 to be measured, realizing the compensation detection of the complex surface optical element 6 to be measured.

[0047] In some embodiments, the beam reduction system 2 performs beam shaping on the beam emitted by the interferometer 1, the polarizer 3 converts the shaped beam into linearly polarized light, and the linearly polarized light is converted into a measurement wavefront by the compensation device 4 for the complex surface optical element.

[0048] In some embodiments, the standard spherical lens 5 is used to converge the measurement wavefront.

[0049] It should be noted that the present invention utilizes an interferometer 1, a beam reduction system 2, a compensation device 4 for complex curved optical elements, a polarizer 3, etc., to rapidly detect various complex curved optical elements such as aspherical surfaces and free-form surfaces, especially complex curved optical elements with large deviation amounts. For the complex curved optical element 6 to be measured, first, the sagittal height deviation of the ideal spherical lens closest to it is obtained according to the design data of the complex curved optical element, the compensation amounts of the complex curved optical element 6 to be measured are corresponded to the Zernike coefficients one by one, and various primary aberrations that the complex curved optical element 6 to be measured needs to be compensated are analyzed; then, according to the model and quantity of the spatial light modulator 4-1 built in the compensation device 4 for complex curved optical elements, a simulation software is used to determine the maximum amplitudes of different Zernike aberration modes that can be achieved by the selected SLM at different quantization levels; finally, it is necessary to combine the compensation data of the complex curved optical element 6 to be measured and the maximum amplitude data that the selected spatial light modulator 4-1 can generate, and based on the modulation capabilities of each spatial light modulator 4-1, design the compensation device 4 for complex curved optical elements and set the relevant parameters of the spatial light modulator 4-1. During the test, only the complex curved optical element 6 to be measured needs to be placed in the measurement optical path, and the compensation device 4 for complex curved optical elements set in advance will compensate for the large sagittal height deviation between the complex curved optical element 6 to be measured and the ideal spherical mirror closest to it, thereby realizing the compensation interference detection of the complex curved optical element.

[0050] Embodiment 1

[0051] Step 1: First, reasonably characterize the complex curved optical element 6 to be measured, and correspond the compensation aberration data of the complex curved optical element 6 to be measured to the Zernike coefficients one by one.

[0052] Taking the complex curved optical element 6 to be measured as an aspherical optical element as an example, the aspherical optical element is characterized by the following formula:

[0053] ;

[0054] Wherein, is the sagittal height of the aspherical optical element, is the radial aperture of the aspherical optical element, is the vertex curvature of the aspherical optical element, k is defined as the conic constant, , , are all high-order term coefficients.

[0055] And the ideal spherical mirror is characterized by the following formula:

[0056] ;

[0057] Wherein, is the sagittal height of the ideal spherical mirror, $C_0$ is the vertex curvature of the ideal spherical mirror, and $r$ is the radial aperture of the ideal spherical mirror.

[0058] In order to intuitively obtain the deviation between the aspherical optical element and the ideal spherical mirror, the above two equations are respectively expanded by Taylor series and then subtracted, and the following can be obtained:

[0059] ;

[0060] ;

[0061] where $z$ is the sagittal height difference between the aspherical optical element and the ideal spherical mirror, $c$ is the vertex curvature of the aspherical optical element or the ideal spherical mirror, and $r$ is the radial aperture of the aspherical optical element or the ideal spherical mirror.

[0062] The above formula is the sagittal height deviation amount between the aspherical optical element and its closest ideal spherical mirror. Generally, after the complex surface optical element is precisely polished, the interference detection is carried out, and its surface shape change is mostly continuous and gentle. According to the Zernike aberration theory, this deviation amount can be characterized by the linear combination of a finite number of standard Zernike circular polynomials, that is, the above formula is expressed in the form of the following formula:

[0063] ;

[0064] In the formula, is the Zernike polynomial The coefficient of, and the absolute value of it characterizes the magnitude of the aberration that needs to be compensated corresponding to the complex surface optical element 6 to be measured. Based on this, calculations can be carried out for any continuously smooth complex surface optical element 6 to be measured, and the aberration data to be compensated of the complex surface optical element 6 to be measured is corresponded to the Zernike polynomial coefficients one by one, effectively quantifying various aberrations that need to be compensated, and providing a reference for the design of the compensation device 4 of the complex surface optical element.

[0065] Step 2: Simulate and determine the maximum amplitude of different Zernike aberration modes that can be achieved by the selected SLM at different quantization levels.

[0066] In the interference surface shape detection of the aspherical optical element, the wavefront emitted by the interferometer 1 needs to pass through the compensator or the compensation device 4 of the complex surface optical element, and is changed into the measurement wavefront. After carrying the surface shape information of the aspherical optical element, it can return to the interferometer 1 along the original path. As a programmable adaptive diffractive optical element, the spatial light modulator 4-1 (SLM) can, under the control of the applied signal, change the amplitude, polarization state or phase of the light distribution in space, or convert incoherent light into coherent light, write specific information into the light field, and realize wavefront modulation.

[0067] Such as Figure 3As shown in the figure, the reflective (liquid crystal) spatial light modulator 4-1-1 includes a glass plate 7 or an optical fiber panel, a conductive electrode 8, an alignment layer 9, a liquid crystal layer 10, a mirror 11, a control electrode 12, and a silicon substrate 13. Due to the birefringence effect of the crystal, when light passes through the liquid crystal layer 10 sandwiched between the electrodes, there will be two refracted light rays. For one of them, the propagation law conforms to the law of refraction. That is, for this light ray, the refracted ray is always in the incident plane, and the ratio of the sine value of the incident angle to the sine value of the refracted angle is always a constant. This light is called the ordinary light, abbreviated as o light (ordinary light); the propagation of the other light does not conform to the law of refraction. The refractive index changes with the incident angle, the ratio of the sine value of the incident angle to the sine value of the refracted angle is not a constant, and the refracted ray is often not in the incident plane. This light is called the extraordinary light. Under the influence of an external electric field, the refractive index of the o light remains constant, and the refractive index value of the e light changes with the amplitude of the voltage. Therefore, under the action of the electric field, the phase of the incident light will undergo a controlled delay after passing through the SLM, and the phase difference is equivalent to:

[0068] ;

[0069] where λ is the wavelength of the incident light, d is the thickness of the liquid crystal layer 10, and are the refractive index of the extraordinary light and the refractive index of the ordinary light respectively.

[0070] Design corresponding grayscale images for specific phase modulation or wavefront control targets (load different grayscale images onto the spatial light modulator 4-1 for different types of aberrations so that the spatial light modulator 4-1 can correspondingly compensate for different types of aberrations). By applying different voltages to the SLM, phase modulation can be achieved. This is the working principle of phase modulation based on the electro-optic birefringence effect of the SLM.

[0071] Based on this theory, through computer simulation, determine the maximum amplitudes of different Zernike aberration modes that can be achieved by the selected SLM of the compensation device 4 for complex curved optical elements at different quantization levels. The specific simulation process is as follows: Divide the phase plane of the spatial light modulator 4-1 into grids, generate Zernike aberrations of specific patterns with normalized coefficients on the grids, and calculate the maximum amplitude of the phase gradient modulus of the Zernike aberrations , determine the quantization level, and obtain the average amplitude of the Zernike aberration modes that can be achieved by the SLM at the n quantization level . For example: For a single spatial light modulator 4-1, the first step is to divide the phase plane of the spatial light modulator 4-1 into grids, and generate the maximum amplitudes of the phase gradient moduli of the respective Zernike aberrations of the five aberration types of tilt, defocus, astigmatism, coma, and spherical aberration with normalized coefficients on the grids ; The second step is: determining the quantization levels, and obtaining the respective average amplitudes of the five types of aberrations including tilt, defocus, astigmatism, coma, and spherical aberration that can be achieved by SLM at n quantization levels. .

[0072] Figure 4 The average amplitude situation of the Zernike aberrations that can be generated by a certain spatial light modulator 4-1 when the set quantization level is 8 is given. Among them, Z1 = Z2 is used to compensate for tilt, Z3 is used to compensate for defocus, Z4 = Z5 is used to compensate for astigmatism, Z6 = Z7 is used to compensate for coma, and Z8 is used to compensate for spherical aberration.

[0073] Step 3: Combining the compensation amount of the complex curved surface optical element 6 to be measured and the maximum amplitude data that the selected spatial light modulator 4-1 can generate, reasonably allocate the modulation ability of the spatial light modulator 4-1, and design the compensation device 4 for the complex curved surface optical element for detection.

[0074] According to Step 2, the maximum limit aberrations that the spatial light modulator 4-1 can modulate are known, and through the derivation in Step 1, the aberrations that the aspherical optical element needs to compensate are also known. If a single spatial light modulator 4-1 can meet the compensation requirements, then naturally a single spatial light modulator 4-1 can achieve compensation. However, in actual requirements, it is often more complex. The modulation ability of a single spatial light modulator 4-1 is limited. At this time, only need to reasonably allocate multiple spatial light modulators 4-1 so that their cumulative effect can compensate for the aberrations that the complex curved surface optical element 6 to be measured needs to compensate. For example: A certain complex curved surface optical element needs to compensate for 18λ of astigmatism and 6λ of coma. According to Figure 4 the data in, two identical spatial light modulators 4-1 can be selected for compensation, design the corresponding grayscale image, load different voltages on the SLM, and the two identical spatial light modulators 4-1 are respectively used to compensate for the astigmatism and coma of the complex curved surface optical element 6 to be measured, and build the optical path as shown in Figure 2 to carry out the compensation test work for the mirror surface shape to be measured.

[0075] In the actual detection process, according to the type and modulation ability of the selected spatial light modulator 4-1, etc., the compensation device 4 for the complex curved surface optical element may have other forms, including but not limited to the several forms shown in Fig. 5(a)-Fig. 5(c). Among them, Fig. 5(a) is a multi-reflection type compensation device 4, which is composed of three reflective spatial light modulators 4-1-1. Fig. 5(b) is a combined transmission and reflection type compensation device 4, which is composed of one reflective spatial light modulator 4-1-1 and one transmissive spatial light modulator 4-1-2. Fig. 5(c) is a multi-transmission type compensation device 4, which is composed of three transmissive spatial light modulators 4-1-2. The above all belong to the protection scope of this patent.

[0076] It should be understood that the various forms of processes shown above can be used, with steps reordered, added or deleted. For example, the steps recited in the disclosure of the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitation is imposed herein.

[0077] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A compensation detection device for a complex surface optical element, comprising an interferometer, a beam reducing system, a polarizer, a compensation device for the complex surface optical element, and a standard spherical lens sequentially arranged along the beam exit direction of the interferometer. The beam emitted by the interferometer is converted into a measurement wavefront through the beam reducing system, the polarizer, and the compensation device for the complex surface optical element. After the measurement wavefront is incident on the complex surface optical element to be measured for reflection through the standard spherical lens, it returns along the original path to the interferometer to form interference fringes containing the surface shape information of the complex surface optical element to be measured, realizing the compensation detection of the complex surface optical element to be measured; The compensation device for the complex surface optical element includes no less than 1 spatial light modulator. The design method of the compensation device for the complex surface optical element specifically includes the following steps: S1: Calculate the sag offset between the complex surface optical element to be measured and the ideal spherical mirror, and represent the sag offset by the linear combination of a finite number of standard Zernike circular polynomials to obtain the aberration data to be compensated for the complex surface optical element to be measured; S2: Determine the quantization level, and calculate the maximum amplitude of each type of spatial light modulator at the same quantization level under different Zernike aberration modes; S3: Based on the aberration data to be compensated for the complex surface optical element to be measured and the maximum amplitude of each type of spatial light modulator under different Zernike aberration modes, select the types and quantities of the spatial light modulators participating in the compensation in the compensation device; S4: Load the grayscale map corresponding to the aberration type in each of the spatial modulators selected in step S3, and apply different voltages to the selected spatial modulators to complete the design of the compensation device.

2. The compensation detection device for complex surface optical elements according to claim 1, wherein: In step S1, the vertex curvature radius value of the complex surface optical element to be measured is the same as the vertex curvature radius value of the ideal spherical mirror; the aberration data to be compensated includes tilt compensation value, defocus compensation value, astigmatism compensation value, coma compensation value, and spherical aberration compensation value.

3. The compensation detection device for complex surface optical elements according to claim 1, wherein: In step S1, the sag offset is characterized by a linear combination of a finite number of standard Zernike circular polynomials : ； Among them, is the i-th Zernike coefficient, is the i-th Zernike polynomial, is the radial coordinate, is the angular coordinate, n is the upper bound, Z0 is the translation, Z1 is the tilt about the x-axis, Z2 is the tilt about the y-axis, Z3 is the defocus, Z4 is the astigmatism at 0 degrees and defocus, Z5 is the astigmatism at 45 degrees and defocus, Z6 is the coma and tilt about the x-axis, Z7 is the coma and tilt about the y-axis, Z8 is the spherical aberration and defocus.

4. The compensation detection device for a complex curved optical element according to claim 1, characterized in that: In step S2, the Zernike aberration modes include tilt, defocus, astigmatism, coma, and spherical aberration.

5. The compensation detection device for complex surface optical elements according to claim 1, wherein: The beam reducing system shapes the beam emitted by the interferometer, the polarizer converts the shaped beam into linearly polarized light, and the linearly polarized light is converted into a measurement wavefront through the compensation device for the complex surface optical element.

6. The compensation detection device for a complex surface optical element according to claim 1, characterized in that: The standard spherical lens is used to converge the measurement wavefront.

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