Compensation device design method of complex curved surface optical element and compensation detection device

Abstract

The invention belongs to the technical field of optical detection, and particularly relates to a compensation device design method of a complex curved surface optical element and a compensation detection device. The method comprises the following steps: S1, representing rise offset by using a linear combination of a finite term standard Zernike circular polynomial to obtain aberration data to be compensated of a complex curved surface optical element to be measured; s2, obtaining the maximum amplitude values of various spatial light modulators in different Zernike aberration modes; s3, selecting the spatial light modulator participating in compensation in the compensation device based on aberration data to be compensated of the complex curved surface optical element to be measured and the maximum amplitudes of various spatial light modulators in different Zernike aberration modes; and S4, loading grey-scale maps corresponding to the aberration types in the spatial modulators selected in the step S3, so that the selected spatial modulators are loaded with different voltages, and the design of the compensation device is completed. On the basis of the original high precision of interference compensation detection, the universality is greatly improved.

Description

Technical Field

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

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

[0003] The detection methods of complex curved optical components can be divided into non-interference detection methods and interference detection methods. Non-interference detection methods are a general term for a type of detection methods that do not use the interference principle to detect the surface shape of the optical surface to be measured, such as: profilometer method and laser tracker method. Non-interference detection methods are generally versatile, but the surface shape detection accuracy is limited. The surface shape detection accuracy is generally between microns and sub-microns, and is mostly used for detection in the milling, grinding and rough polishing stages of the processing of complex curved optical components. Interference detection method is a type of detection method that uses the principle of light wave interference to detect the surface shape of the optical surface to be measured, such as: computational holography and multi-wavelength interferometry. Because of its nanometer-level detection accuracy, interference detection method is currently more common in surface shape detection in the fine polishing stage of complex curved optical components. The core of the interference detection method for detecting complex curved optical elements is to solve the problem of too dense interference fringes caused by the large deviation between complex curved optical elements and the reference surface. The most commonly used method is to design different compensators (such as computer-generated holographic 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 the optical system, it is often necessary to process different compensators for each different optical surface to be tested. Therefore, the use of compensators to detect complex curved optical elements has the problems of poor versatility, long detection cycle and high cost. Therefore, the demand for interference detection methods that can realize highly universal aberration compensation for different complex curved optical elements in surface shape detection is becoming more and more urgent.

[0004] In order to solve the above contradiction, domestic and foreign scholars have conducted relevant research in recent years. However, the above studies generally use 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 the use of a single compensator requires all primary aberrations to be compensated at one time, which will further compress the adaptive compensator's ability to compensate for a single aberration, making it difficult to measure complex curved optical elements with large single aberrations. Summary of the invention

[0005] In view of this, the present invention aims to provide a compensation device design method and a compensation detection device for complex curved optical elements, so as to solve the problem that the prior art has limited compensation ability for the aberrations of complex curved optical elements and it is difficult to measure the complex curved optical elements to be measured with a single large aberration. Based on the original high precision of interference compensation detection, the present invention greatly improves the versatility, which helps to further realize the detection of complex curved optical elements with large deviations.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows: A method for designing a compensation device for a complex curved optical element, wherein the compensation device includes at least one spatial light modulator, and specifically includes the following steps: S1: Calculate the sag offset of the complex curved optical element to be tested and the ideal spherical mirror, and characterize the sag offset using a linear combination of finite-term standard Zernike circular polynomials to obtain the aberration data to be compensated for the complex curved optical element to be tested; S2: Determine the quantization level and calculate the maximum amplitude of various spatial light modulators at the same quantization level under different Zernike aberration modes; S3: Based on the aberration data to be compensated of the complex curved optical element to be tested and the maximum amplitudes of various spatial light modulators under different Zernike aberration modes, the type and quantity of the spatial light modulators involved in the compensation in the compensation device are selected; S4: Loading a grayscale image corresponding to the aberration type into each spatial modulator selected in step S3, so that each selected spatial modulator is loaded with a different voltage, thereby completing the design of the compensation device.

[0007] Furthermore, in step S1, the value of the vertex curvature radius of the complex curved optical element to be measured is the same as the value of the vertex curvature radius of an ideal spherical mirror; the aberration data to be compensated includes a tilt compensation value, a defocus compensation value, an astigmatism compensation value, a coma compensation value and a spherical aberration compensation value.

[0008] Further, in step S1, the sag offset represented by the linear combination of the finite-term standard Zernike circular polynomials is The expression is: ; in, 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 translation, Z1 is x-axis tilt, Z2 is y-axis tilt, Z3 is defocus, Z4 is astigmatism 0 degrees and defocus, Z5 is astigmatism 45 degrees and defocus, Z6 is coma and x-axis tilt, Z7 is coma and y-axis tilt, and Z8 is spherical aberration and defocus.

[0009] Further, in step S2, the Zernike aberration pattern includes tilt, defocus, astigmatism, coma and spherical aberration.

[0010] A compensation detection device for a complex curved optical element comprises an interferometer and a beam reduction system, a polarizer, a compensation device for the complex curved optical element and a standard spherical lens which are sequentially arranged along the light beam emission direction of the interferometer. The light beam emitted by the interferometer is converted into a measurement wavefront through the beam reduction system, the polarizer and the compensation device for the complex curved optical element. The measurement wavefront is incident on the complex curved optical element to be measured through the standard spherical lens for reflection and then returns to the interferometer along the original path to form interference fringes containing the surface shape information of the complex curved optical element to be measured, thereby realizing compensation detection of the complex curved optical element to be measured.

[0011] Furthermore, the beam reduction system performs beam shaping on the light beam emitted by the interferometer, the polarizer converts the shaped light beam into linearly polarized light, and the linearly polarized light is converted into a measurement wavefront through a compensation device of the complex curved optical element.

[0012] Furthermore, a standard spherical lens is used to converge the measuring wavefront.

[0013] Compared with the prior art, the invention can achieve the following beneficial effects: (1) The compensation device design method and compensation detection device for complex curved optical elements created by the present invention can effectively expand the versatility of using interference detection method to detect complex curved optical elements, improve the applicability of detecting complex curved optical elements with large deviations, and improve detection efficiency. The present invention is of great significance for the processing and application of complex curved optical elements.

[0014] (2) The present invention creates a compensation device design method and a compensation detection device for complex curved optical elements. The present invention proposes a method for compensating and detecting complex curved optical elements using multiple spatial light modulators (SLMs) (which has universality). The deviation between the complex curved optical element and the spherical surface closest to it is fitted with Zernike polynomials and distributed to multiple spatial light modulators (SLMs) for compensation, thereby doubling its aberration compensation capability. Based on the original high precision of interference compensation detection, the present invention greatly improves the universality, which helps to further realize the detection of complex curved optical elements with large deviations.

[0015] (3) The compensation device design method and compensation detection device for complex curved optical elements created by the present invention have stronger versatility compared with traditional compensation detection methods, saving the time cost of "one-to-one" customization of compensators by computational holography. Compared with the method of using a single programmable compensator for interference detection, the present invention performs in advance the distribution and compensation planning of the amount to be compensated of the complex curved optical element to be tested, thereby improving the utilization efficiency of the compensator. Its compensation range is the superposition of the compensation ranges of multiple compensators. The design of the compensation device for complex curved optical elements effectively solves the problem of insufficient compensation of a single compensator, saving the cost of customizing expensive high-end spatial light modulators for extreme detection needs, and greatly improving the applicability of programmable compensators for compensation detection of complex curved optical elements with large deviations. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 A schematic flow chart of a method for designing a compensation device for a complex curved optical element according to an embodiment of the present invention; Figure 2 A schematic diagram of the structure of a compensation detection device for a complex curved optical element according to an embodiment of the present invention; Figure 3 A schematic diagram of the structure of a reflective spatial light modulator according to an embodiment of the present invention; Figure 4 A result diagram of the average amplitude of the Zernike aberration that can be generated by the spatial light modulator 4-1 described in the embodiment of the present invention when the quantization level is set to 8; FIG5 (a) is a schematic diagram of the structure of a multi-reflection compensation device according to an embodiment of the present invention; FIG5( b ) is a schematic diagram of the structure of a transmission and reflection combined compensation device according to an embodiment of the present invention; FIG5( c ) is a schematic diagram of the structure of a multi-transmission compensation device according to an embodiment of the present invention.

[0017] Description of reference numerals: 1. Interferometer; 2. Beam reduction 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. Reflector; 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. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and 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 therefore cannot be understood as a limitation on 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 technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0021] In the description of the invention, it should be noted that, unless otherwise clearly specified 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0022] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0023] like Figure 1 As shown, the present invention proposes a compensation device design method for a complex curved optical element, the compensation device 4 includes no less than one spatial light modulator 4-1, and specifically includes the following steps: S1: calculating the vector height offset of the complex curved optical element 6 to be tested and the ideal spherical mirror, and characterizing the vector height offset by a linear combination of a finite-term standard Zernike circular polynomial to obtain the aberration data to be compensated of the complex curved optical element 6 to be tested; S2: determining the quantization level, and calculating the maximum amplitudes of various types of spatial light modulators 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 optical element 6 to be tested and the maximum amplitudes of various types of spatial light modulators 4-1 under different Zernike aberration modes, selecting the type and quantity of spatial light modulators 4-1 participating in the compensation in the compensation device 4; S4: loading a grayscale image corresponding to the aberration type into each spatial modulator selected in step S3, so that each selected spatial modulator is loaded with a different voltage, and the design of the compensation device 4 is completed.

[0024] It should be noted that the present invention proposes a method for universal compensation detection of complex curved optical elements using multiple SLMs in response to the existing surface shape detection requirements of complex curved optical elements. The method can achieve high universal detection of complex curved optical elements with large deviations based on multiple SLMs. In addition, the quantization level is defined as the number of bits used to record the binary value of the digital image color in the spatial light modulator 4-1. The larger the index, the higher the modulation accuracy. The quantization level is set according to the accuracy required by the user.

[0025] In some embodiments, in step S1, the value of the vertex curvature radius of the complex curved optical element 6 to be measured is the same as the value of the vertex curvature radius of an ideal spherical mirror; the aberration data to be compensated includes a tilt compensation value, a defocus compensation value, a coma compensation value, a coma compensation value and a spherical aberration compensation value.

[0026] In some embodiments, in step S1, the sag offset is characterized by a linear combination of finite-term standard Zernike circular polynomials. The expression is: ; in, 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 0 degrees and defocus; Z5 is astigmatism 45 degrees and defocus; Z6 is coma and x-axis tilt; Z7 is coma and y-axis tilt; Z8 is spherical aberration and defocus.

[0027] In some embodiments, in step S2, the Zernike aberration pattern includes tilt, defocus, astigmatism, coma and spherical aberration.

[0028] like Figure 2 As shown, the present invention proposes a compensation detection device for complex curved optical elements, comprising an interferometer 1 and a beam reduction system 2, a polarizer 3, a compensation device 4 for complex curved optical elements and a standard spherical lens 5 which are arranged in sequence along the light beam emission direction of the interferometer 1. The light beam emitted by the interferometer 1 is converted into a measurement wavefront through the beam reduction system 2, the polarizer 3 and the compensation device 4 for complex curved optical elements. The measurement wavefront is incident on the complex curved optical element 6 to be measured through the standard spherical lens 5 and is reflected. Then, the measurement wavefront returns to the interferometer 1 along the original path to form interference fringes containing the surface shape information of the complex curved optical element 6 to be measured, thereby realizing compensation detection of the complex curved optical element 6 to be measured.

[0029] In some embodiments, the beam reduction system 2 performs beam shaping on the light beam emitted by the interferometer 1, the polarizer 3 converts the shaped light beam into linearly polarized light, and the linearly polarized light is converted into a measurement wavefront through the compensation device 4 of the complex curved optical element.

[0030] In some embodiments, a standard spherical lens 5 is used to focus the measuring wavefront.

[0031] 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, and 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 deviations. For the complex curved optical element 6 to be tested, first, the deviation of the vector height of the ideal spherical lens closest to it is obtained according to the design data of the complex curved optical element, the amount to be compensated of the complex curved optical element 6 to be tested is matched one by one with the Zernike coefficient, and various primary aberrations that need to be compensated for the complex curved optical element 6 to be tested are analyzed; then, according to the model and number of spatial light modulators 4-1 built in the compensation device 4 of the complex curved optical element, the maximum amplitudes of different Zernike aberration modes that can be achieved by the selected SLM at different quantization levels are determined using simulation software; finally, it is necessary to combine the compensation data of the complex curved optical element 6 to be tested and the maximum amplitude data that can be generated by the selected spatial light modulator 4-1, and based on the modulation capabilities of each spatial light modulator 4-1, design the compensation device 4 of the complex curved optical element and set the relevant parameters of the spatial light modulator 4-1. During the test, it is only necessary to place the complex curved optical element 6 to be tested into the measuring light path, and the compensation device 4 of the complex curved optical element set in advance will compensate for the large vector height deviation between the complex curved optical element 6 to be tested and the ideal spherical mirror closest to it, thereby realizing the compensatory interference detection of the complex curved optical element.

[0032] Example 1 Step 1: Firstly, the complex curved surface optical element 6 to be tested is reasonably characterized, and the aberration data to be compensated of the complex curved surface optical element 6 to be tested is matched one by one with the Zernike coefficients.

[0033] Taking the complex curved surface optical element 6 to be measured as an aspherical optical element as an example, the aspherical optical element is characterized by the following formula: ; in, is the sag of the aspheric optical element, is the radial aperture of the aspheric optical element, is the vertex curvature of the aspheric optical element, k is defined as the quadratic constant, , , All are high-order coefficients.

[0034] The ideal spherical mirror is characterized by the following formula: ; in, is the sag of an ideal spherical mirror, is the vertex curvature of the ideal spherical mirror, and r is the radial aperture of the ideal spherical mirror.

[0035] In order to intuitively obtain the deviation between the aspheric optical element and the ideal spherical mirror, the above two equations are Taylor expanded and subtracted to obtain: ; ; Wherein, z is the difference in sagittal height between the aspheric optical element and the ideal spherical mirror, c is the vertex curvature of the aspheric optical element or the ideal spherical mirror, and r is the radial aperture of the aspheric optical element or the ideal spherical mirror.

[0036] The above formula is the deviation of the sag between the aspheric optical element and its closest ideal spherical mirror. Generally, complex curved optical elements are subjected to interference detection after precision polishing, and their surface shape changes are mostly continuous and gentle. According to Zernike aberration theory, this deviation can be characterized by a linear combination of finite-term standard Zernike circular polynomials, that is, the above formula can be expressed as the following form: ; In the formula, Zernike polynomials The absolute value of the coefficient represents the size of the aberration that needs to be compensated for the corresponding complex curved optical element 6 to be tested. Based on this, calculations can be performed for any continuous and smooth complex curved optical element 6 to be tested, and the aberration data to be compensated of the complex curved optical element 6 to be tested can be matched one by one with the Zernike polynomial coefficients, so as to effectively quantify the various types of aberrations that need to be compensated, and provide a reference for the design of the compensation device 4 for the complex curved optical element.

[0037] Step 2: Simulate and determine the maximum amplitudes of different Zernike aberration modes that can be achieved by the selected SLM at different quantization levels.

[0038] In the interference surface shape detection of aspheric optical elements, the wavefront emitted by the interferometer 1 needs to pass through the compensator or the compensation device 4 of the complex curved optical element, and is changed into a measurement wavefront, which can be returned to the interferometer 1 along the original path after carrying the surface shape information of the aspheric optical element. As a programmable adaptive diffraction optical element, the spatial light modulator 4-1 (SLM) can change the amplitude, polarization state or phase of the light distribution in space under the control of the applied signal, or convert incoherent light into coherent light, write specific information into the light field, and realize wavefront modulation.

[0039] like Figure 3As shown, 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 reflector 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, one of which has a propagation law that conforms to the law of refraction, that is, for this light ray, the refracted light ray is always on the incident plane, and the ratio of the sine value of the incident angle to the sine value of the refraction angle is always a constant. This light is called ordinary light, or o light for short; 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 refraction angle is not a constant, and the refracted light ray is often not on the incident plane. This light is called extraordinary light. Under the influence of the external electric field, the refractive index of the o light remains constant, and the refractive index value of the e light changes with the change of the voltage amplitude. Therefore, under the action of the electric field, the phase of the incident light will be controlled to be delayed after passing through the SLM. is equivalent to: ; Wherein, λ is the wavelength of the incident light, d is the thickness of the liquid crystal layer 10, , are the refractive index of extraordinary light and the refractive index of ordinary light respectively.

[0040] By designing a corresponding grayscale image for a specific phase modulation or wavefront control target (loading different grayscale images to the spatial light modulator 4-1 for different types of aberrations so that the spatial light modulator 4-1 can compensate for different types of aberrations), and loading different voltages on the SLM, phase modulation can be achieved. This is the working principle of phase modulation based on the electrically controlled birefringence effect of the SLM.

[0041] Based on this theory, the maximum amplitudes of different Zernike aberration modes that can be achieved by the SLM selected by the compensation device 4 of the complex curved optical element at different quantization levels are determined by computer simulation. The specific simulation process is as follows: a grid is divided on the phase plane of the spatial light modulator 4-1, a Zernike aberration of a specific mode with normalized coefficients is generated on the grid, and the maximum amplitude of the phase gradient mode of the Zernike aberration is calculated. , determine the quantization level, and obtain the average amplitude of the Zernike aberration pattern that the SLM can achieve under n quantization levels 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 a grid, and generate the maximum amplitude of the phase gradient modulus of the five aberration types of tilt, defocus, astigmatism, coma and spherical aberration of the normalized coefficients on the grid. The second step is to determine the quantization level and obtain the average amplitude of the five aberration types of tilt, defocus, astigmatism, coma and spherical aberration that can be achieved by the SLM under n quantization levels. .

[0042] Figure 4 The calculated average amplitude of the Zernike aberration that can be produced by a certain spatial light modulator 4-1 when the quantization level is set to 8 is given, where 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.

[0043] Step 3: Based on the compensation amount of the complex curved optical element 6 to be tested and the maximum amplitude data that can be generated by the selected spatial light modulator 4-1, the modulation capacity of the spatial light modulator 4-1 is reasonably allocated, and the compensation device 4 of the complex curved optical element is designed for testing.

[0044] According to step 2, the maximum limit aberration that the spatial light modulator 4-1 can modulate is known. The aberration that the aspheric optical element needs to compensate is also known after the derivation of step 1. If one spatial light modulator 4-1 can meet the compensation requirements, then naturally a single spatial light modulator 4-1 can achieve compensation. However, actual requirements are often more complicated. The modulation capacity of a single spatial light modulator 4-1 is limited. At this time, it is only necessary to reasonably allocate multiple spatial light modulators 4-1 so that they can be accumulated to compensate for the aberrations that need to be compensated for the complex curved optical element 6 to be tested. For example: a complex curved optical element needs to compensate for 18λ astigmatism and 6λ coma. According to Figure 4 According to the data in the image processing apparatus, two spatial light modulators 4-1 of the same type can be selected for compensation, and the corresponding grayscale image can be designed. Different voltages are loaded on the SLM. The two spatial light modulators 4-1 of the same type are used to compensate for the astigmatism and coma of the complex curved optical element 6 to be tested. Figure 2 The optical path shown is used to carry out compensation test of the mirror shape to be tested.

[0045] In the actual detection process, according to the type and modulation capability of the selected spatial light modulator 4-1, the compensation device 4 of the complex curved optical element may have other forms, including but not limited to the several forms shown in Figures 5 (a) to 5 (c), wherein Figure 5 (a) is a multi-reflection compensation device 4, which is composed of three reflective spatial light modulators 4-1-1, Figure 5 (b) is a transmission and reflection combined compensation device 4, which is composed of a reflective spatial light modulator 4-1-1 and a transmission spatial light modulator 4-1-2, and Figure 5 (c) is a multi-transmission compensation device 4, which is composed of three transmission spatial light modulators 4-1-2. All of the above belong to the protection scope of this patent.

[0046] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0047] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing a compensation device for a complex curved optical element, wherein the compensation device comprises at least one spatial light modulator, characterized in that: The specific steps include: S1: Calculate the sag offset of the complex curved optical element to be tested and the ideal spherical mirror, and characterize the sag offset using a linear combination of finite-term standard Zernike circular polynomials to obtain the aberration data to be compensated for the complex curved optical element to be tested; S2: Determine the quantization level and calculate the maximum amplitude of various spatial light modulators at the same quantization level under different Zernike aberration modes; S3: Based on the aberration data to be compensated of the complex curved optical element to be tested and the maximum amplitudes of various spatial light modulators under different Zernike aberration modes, the type and quantity of the spatial light modulators involved in the compensation in the compensation device are selected; S4: Loading a grayscale image corresponding to the aberration type into each spatial modulator selected in step S3, so that each selected spatial modulator is loaded with a different voltage, thereby completing the design of the compensation device.

2. The method for designing a compensation device for a complex curved optical element according to claim 1, characterized in that: In step S1, the value of the vertex curvature radius of the complex curved optical element to be measured is the same as the value of the vertex curvature radius of an ideal spherical mirror; the aberration data to be compensated include a tilt compensation value, a defocus compensation value, an astigmatism compensation value, a coma compensation value and a spherical aberration compensation value.

3. The method for designing a compensation device for a complex curved optical element according to claim 1, characterized in that: In step S1, the sag offset is characterized by a linear combination of finite-term standard Zernike circular polynomials: : ； in, 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 translation, Z1 is x-axis tilt, Z2 is y-axis tilt, Z3 is defocus, Z4 is astigmatism 0 degrees and defocus, Z5 is astigmatism 45 degrees and defocus, Z6 is coma and x-axis tilt, Z7 is coma and y-axis tilt, and Z8 is spherical aberration and defocus.

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

5. A compensation detection device for complex curved optical elements, characterized in that: The method comprises an interferometer and a beam reduction system, a polarizer, a compensation device for a complex curved optical element as claimed in any one of claims 1 to 4, which are sequentially arranged along the light beam emission direction of the interferometer, and a standard spherical lens. The light beam emitted by the interferometer is converted into a measurement wavefront through the beam reduction system, the polarizer and the compensation device for the complex curved optical element. After the measurement wavefront is incident on the complex curved optical element to be measured through the standard spherical lens and reflected, it returns to the interferometer along the original path to form interference fringes containing the surface shape information of the complex curved optical element to be measured, thereby realizing compensation detection of the complex curved optical element to be measured.

6. The compensation detection device for complex curved optical elements according to claim 5, characterized in that: The beam reduction system performs beam shaping on the light beam emitted by the interferometer, the polarizer converts the shaped light beam into linear polarized light, and the linear polarized light is converted into a measurement wavefront through the compensation device of the complex curved optical element.

7. The compensation detection device for complex curved optical elements according to claim 5, characterized in that: The standard spherical lens is used to converge the measuring wavefront.

Images