Wide-viewing-angle wavefront sensing device

Abstract

The invention relates to the technical field of optics, and discloses a wide-viewing-angle wavefront sensing device, which constructs an image space telecentric light path through the combination of a diaphragm and a lens group and the arrangement of the diaphragm at the object space focus of the lens group, so that the wavefront of large-angle incidence becomes the wavefront of the incidence of main light rays vertical to a micro lens array after passing through the image space telecentric light path, and the wavefront of the incidence of the main light rays vertical to the micro lens array is formed. The photoelectric sensor is located on the focal plane of the micro-lens array, so that after incident wavefronts at different angles are incident through the diaphragm and are refracted by the lens group, main light rays of the refracted incident wavefronts are vertically and orthogonally incident into the plane of the micro-lens array, are segmented by the micro-lens array and then are transmitted forwards; focusing light spots corresponding to incident wavefronts are formed on the photoelectric sensor, so that the angle detection range of the wavefront sensor is expanded, the wavefront reconstruction precision is improved, and wavefront information of incident light beams in a large field of view is measured at the same time.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to a wide-viewing angle wavefront sensing device. Background Art

[0002] When light waves are generated, propagated, or pass through optical systems or media (such as the atmosphere, biological tissue, turbulence, or the optical system itself), their wavefront shape (equal phase surfaces) deviates from the ideal spherical or plane wave. This phenomenon is called wavefront distortion or wave aberration. Wavefront distortion can cause blurred images and reduced contrast in optical systems, further impacting functions such as imaging, sensing, measurement, and display. To correct wavefront distortion, it is necessary to be able to quickly and accurately measure the wavefront's phase distribution distortion information.

[0003] The Shack-Hartmann wavefront sensor, currently the most mainstream and widely used, can cause the light spot to shift into adjacent sub-apertures or even completely outside the detector's active area when the wavefront is incident at a large angle. Furthermore, the irregular and aberrated light spot formed by the microlens can affect the determination of the light spot's position, reducing the accuracy of the reconstructed wavefront. This makes it impossible to overcome the limitations of the microlens array's inherent field of view on the detectable beam angle, and it is difficult to simultaneously measure wavefront information for beams of varying angles within a large field of view. Summary of the Invention

[0004] In light of this, the present invention provides a wide-angle wavefront sensing device that addresses the viewing angle issue of current wavefront sensors. Specifically, when a wavefront is incident at a large angle, the light spot can shift into adjacent sub-apertures, or even completely outside the detector's effective area. Furthermore, the irregular and aberrated light spot formed by the large-angle incident wavefront passing through the microlens can affect the determination of the light spot's position, reducing the accuracy of the reconstructed wavefront. This makes it difficult to overcome the limitations imposed by the microlens array's inherent field of view on the detectable light beam angle, and hinders the simultaneous measurement of wavefront information for beams of varying angles within a wide field of view.

[0005] A first aspect of the present invention provides a wide-viewing angle wavefront sensing device, comprising: an aperture, a lens group, a microlens array, and a photoelectric sensor sequentially arranged along the direction of the entrance pupil light;

[0006] The aperture is located at the object focus of the lens group;

[0007] The photoelectric sensor is located on the focal plane of the microlens array;

[0008] The microlens array comprises a plurality of identical microlens units arranged at a certain period in a plane;

[0009] After a plurality of incident wavefronts at different angles are incident through the aperture and refracted by the lens group, the main light rays of each refracted incident wavefront are perpendicularly incident on the plane of the microlens array, and are split by the microlens array and propagate forward, forming focused light spots corresponding to each incident wavefront on the photoelectric sensor.

[0010] Optionally, the aperture of the aperture is less than or equal to two-thirds of the effective clear aperture of the lens group.

[0011] Optionally, the number of microlens units in the microlens array in the x and y directions is between 10 and 100.

[0012] Optionally, the device further includes:

[0013] The center distance between the microlens array and the lens group is limited by the spatial sampling rate of the wavefront to be measured.

[0014] Optionally, the higher the spatial sampling rate, the smaller the center distance between the microlens array and the lens group; and the lower the spatial sampling rate, the larger the center distance between the microlens array and the lens group.

[0015] Optionally, the lens group includes at least one collimating lens.

[0016] Optionally, the photoelectric sensor is a CCD camera or a CMOS sensor.

[0017] Optionally, an object-image conjugate system is provided on the optical path between the photosensor and the microlens array.

[0018] In a second aspect, the present invention further provides a wavefront aberration detection method using the wide-viewing angle wavefront sensing device as described in the first aspect, comprising:

[0019] The slope information of each incident wavefront in two orthogonal directions is obtained by comparing the centroid position of the focused light spot corresponding to each incident wavefront received by the photoelectric sensor with the centroid position of the reference light spot; wherein the centroid position of the reference light spot is the centroid position of the standard light spot when there is no aberration;

[0020] The slope information is fitted into a Zernike polynomial, and the complete phase distribution of each incident wavefront is reconstructed according to the Zernike polynomial.

[0021] As can be seen from the above technical solutions, the present invention constructs an image-side telecentric optical path by combining an aperture and a lens group, and by locating the aperture at the object-side focus of the lens group, so that the wavefront incident at a large angle becomes a wavefront with a main ray perpendicular to the microlens array after passing through the image-side telecentric optical path. The photoelectric sensor is located on the focal plane of the microlens array, so that after multiple incident wavefronts at different angles are incident through the aperture and refracted by the lens group, the main ray of each refracted incident wavefront is perpendicular to the plane of the microlens array and is split by the microlens array and propagates forward, forming a focused light spot corresponding to each incident wavefront on the photoelectric sensor, thereby expanding the angular detection range of the wavefront sensor and improving the accuracy of reconstructed wavefront. The image-side telecentric optical path easily solves the problem of breaking through the limitation of the field of view angle of the microlens array itself on the detectable light beam incident angle, and realizes simultaneous detection of multi-angle wavefronts through the optical path design, thereby realizing simultaneous measurement of wavefront information of light beams of various incident angles in a large field of view. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic structural diagram of a wide-viewing angle wavefront sensing device provided by an embodiment of the present invention;

[0024] Figure 2 Schematic diagram of the wavefront to be measured at 1° incidence provided by an embodiment of the present invention;

[0025] Figure 3 Schematic diagram of the incident wavefront to be measured after removing the first three terms of the Zernike polynomial provided in an embodiment of the present invention;

[0026] Figure 4 A diagram showing a comparison of input and reconstructed Zernike polynomial coefficients (with the first three terms of the Zernike polynomial removed) for a wide-angle wavefront sensing device provided by an embodiment of the present invention at large angles of incidence;

[0027] Figure 5 Schematic diagram of wavefront reconstructed by Zernike polynomial coefficients of a wide-view wavefront sensing device provided by an embodiment of the present invention;

[0028] Figure 6 A graph comparing the input and reconstructed Zernike polynomial coefficients (with the first three terms of the Zernike polynomial removed) of a commercial Shack-Hartmann wavefront sensor provided by an embodiment of the present invention at large angles of incidence;

[0029] Figure 7 A wavefront diagram (with the first three terms of the Zernike polynomial removed) reconstructed using Zernike polynomial coefficients reconstructed using a commercial Shack-Hartmann wavefront sensor provided in an embodiment of the present invention;

[0030] Figure 8 Schematic diagram of a large-angle (15°) incident wavefront passing through a commercial Shack-Hartmann wavefront sensor provided by an embodiment of the present invention;

[0031] Figure 9 A comparison diagram of another incident and reconstructed Zernike polynomial coefficients (with the first three terms of the Zernike polynomial removed) for the wide-viewing angle wavefront sensing device provided by an embodiment of the present invention;

[0032] Figure 10 A diagram of another reconstructed wavefront (with the first three terms of the Zernike polynomial removed) of the wide-viewing angle wavefront sensing device provided by an embodiment of the present invention;

[0033] Figure 11 A flow chart of a wavefront aberration detection method using the wide-viewing angle wavefront sensing device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0035] As the most mainstream and widely used wavefront sensor, the Shack-Hartmann wavefront sensor uses a microlens array to split the incident wavefront into multiple subregions corresponding to each microlens. The wavefront tilt (local wavefront slope) within each subaperture causes a lateral shift in the position of its focused spot on a detector (such as a CCD / CMOS). By comparing the positions of all subaperture spots on the detector with a standard spot position without aberration (referenced to a plane wave), the slopes of the wavefront in two orthogonal directions (X and Y) within each subaperture are determined. Using a specific algorithm, the wavefront distribution (i.e., phase distribution) across the entire aperture can be reconstructed.

[0036] Based on a microlens array and detector structure, the Shack-Hartmann wavefront sensor offers advantages such as relatively simple structure, strong robustness, a wide phase dynamic range (adjustable by selecting the microlens focal length), the ability to simultaneously measure multiple guide stars, and mature technology. However, when the angle of the incident beam (i.e., the angle between the wave vector and the sensor plane) is very large, the light spot may shift into the area of ​​adjacent subapertures or even completely outside the detector's active area, causing distortion or even loss of wavefront information. Furthermore, wavefronts incident at large angles deviate significantly from paraxial conditions when passing through the microlenses, resulting in a focused light spot with significant aberrations, resulting in an irregular spot shape. This can also affect the algorithm's interpretation of the local wavefront slope, severely impacting the accuracy of the reconstructed wavefront. In summary, current Shack-Hartmann wavefront sensors face the challenge of a narrow field of view.

[0037] For this reason, Figure 1 As shown, the embodiment of the present application provides a wide-viewing angle wavefront sensing device, comprising: an aperture 100, a lens group 200, a microlens array 300 and a photoelectric sensor 400 arranged in sequence along the direction of the entrance pupil light;

[0038] The aperture 100 is located at the object focus of the lens group 200;

[0039] The photosensor 400 is located on the focal plane of the microlens array 300;

[0040] The microlens array 300 includes a plurality of identical microlens units arranged at a certain period in a plane;

[0041] After multiple incident wavefronts at different angles are incident through the aperture 100 and refracted by the lens group 200, the main light rays of each refracted incident wavefront are perpendicularly incident on the plane of the microlens array 300, and are split by the microlens array 300 and propagate forward, forming a focused light spot corresponding to each incident wavefront on the photosensor 400.

[0042] The aperture 100 refers to a physical object that limits the light beam in an optical system. In the embodiment of the present application, the aperture 100 is used to limit the range of the incident light.

[0043] The lens group 200 (which may also be a lens) “converts” the wavefront incident at a large angle into a wavefront in which the principal light is perpendicularly incident on the microlens array 300 , thereby expanding the field of view.

[0044] For traditional wavefront sensors, wavefronts incident at large angles (such as light waves with a large tilt angle) will be incident on the microlens array 300 in an "oblique direction", which will cause the microlenses to be unable to effectively split (part of the wavefront exceeds the range of the microlenses) or the focused light spot to be offset too much and exceed the sensor detection range.

[0045] In this embodiment of the present application, the combination of aperture 100 and lens assembly 200, with aperture 100 positioned at the object-side focal point of lens assembly 200, creates an image-side telecentric optical path. This path involves the aperture being located in the front focal plane of the lens, with the exit pupil (the image of the aperture formed by the optical elements behind it) located at infinity. This ensures that the image size remains constant regardless of the distance between the lens and the image sensor. For wavefronts incident at large angles, the image-side telecentric optical path causes the principal ray (the central propagation direction of the wavefront) to first pass through aperture 100 (which restricts it to a valid range) before passing through the lens. Because aperture 100 is at the object-side focal point, this principal ray, after refraction by the lens, propagates parallel to the optical axis (i.e., perpendicular to the plane of the microlens array 300). This avoids detection failures caused by oblique incidence, thereby significantly expanding the field of view.

[0046] A wavefront is a line, curve (in two dimensions), or surface (in three dimensions) connecting all points reached by a wave at the same time as it propagates through a medium. It also refers to the curved surface formed by connecting all points reached by a wave at a given moment. In this device, an aperture 100 is placed at the object focus of the lens. Therefore, wavefronts incident at different angles through aperture 100, after being refracted by the lens, always have their principal ray parallel to the optical axis, that is, perpendicular to the plane of the microlens array 300. This results in wavefronts incident at large angles becoming wavefronts with their principal ray perpendicular to the microlens array 300, i.e., with the principal ray normally incident. As the spherical wave continues to propagate, the wavefront perpendicular to the microlens array 300 is split into a large number of sub-regions, or sub-apertures, by the microlens array 300. Because the photosensor 400 is located on the focal plane of the microlens array 300 (the plane formed by the focal lengths of each microlens unit), each sub-wavefront is focused onto the sensor into a focused spot.

[0047] Furthermore, after passing through the lens, wavefronts with different incident angles, while their principal rays are all parallel to the optical axis (perpendicular to the microlens array 300), are focused at different spatial locations on the relay image plane (the intermediate plane of the lens image formation) behind the lens. As these wavefronts propagate further into the microlens array 300, they cover different areas of the microlens array 300 (without overlapping), enabling simultaneous detection of wavefronts at multiple angles.

[0048] If the subaperture is an ideal plane wave (no tilt), the light spot will fall on the reference light spot position. If the subaperture is tilted (i.e., the local wavefront slope, such as the wavefront tilted in the x or y direction due to aberration), the light spot will shift in the tilt direction.

[0049] The spot position is mainly determined by the centroid position of the spot, which is calculated using an adaptive threshold centroid algorithm. The centroid position of the spot under all microlenses on the sensor is compared with the centroid position of the standard spot without aberration (reference plane wave), and the slope of the wavefront in each sub-aperture in two orthogonal directions (X, Y) is obtained, namely:

[0050]

[0051] Where, 、 are the slopes of the wavefront in the sub-aperture in the X and Y axis directions, 、 are the position offsets of the wavefront in the sub-aperture in the X and Y axis directions, is the focal length of the microlens.

[0052] The slope data is then fitted to a Zernike polynomial using a mathematical algorithm (such as the least squares method). (The Zernike polynomial is a mathematical polynomial defined in a polar coordinate system and is a common method for describing wavefront aberrations. For the Shack-Hartmann wavefront sensor, the Zernike polynomial coefficients of the wavefront can be obtained by fitting the measured slope with the derivative of the Zernike polynomial averaged over the sampling subaperture.) The Zernike polynomial expression is:

[0053]

[0054] Where, represents the wavefront phase distribution function described by the Zernike polynomial expansion, is the coefficient of the kth Zernike polynomial term, is the kth Zernike polynomial basis function, and n is the total number of expansion terms.

[0055] By measuring the slope data of a large number of quantum apertures, the coefficients of the Zernike polynomials of various orders can be inferred by solving the linear equations of "slope-coefficient". , the coefficients of each order Zernike polynomial By substituting it into the Zernike polynomial expression, the wavefront phase can be calculated point by point and the incident wavefront phase distribution map can be reconstructed.

[0056] It should be noted that the above describes the wavefront reconstruction method using the pattern method as an example. The protection scope of the wavefront reconstruction algorithm of the present invention is not limited to the pattern method, and will not be repeated here.

[0057] It should be noted that, in the embodiment of the present application, the aperture 100 and the lens group 200 are combined, and the aperture 100 is located at the object focus of the lens group 200 to construct an image-side telecentric optical path, so that the wavefront incident at a large angle becomes a wavefront with a principal ray perpendicular to the incident microlens array 300 after passing through the image-side telecentric optical path, and the photoelectric sensor 400 is located on the focal plane of the microlens array 300, so that after a plurality of incident wavefronts at different angles are incident through the aperture 100 and refracted by the lens group 200, the principal ray of each refracted incident wavefront is perpendicular to the incident wavefront. Light directly enters the plane of the microlens array 300, is split by the microlens array 300, and then propagates forward, forming focused light spots corresponding to each incident wavefront on the photoelectric sensor 400, thereby expanding the angular detection range of the wavefront sensor and improving the accuracy of reconstructing the wavefront. The image-side telecentric optical path easily solves the problem of breaking through the limitation of the field of view angle of the microlens array 300 itself on the detectable light beam incident angle, and the optical path design realizes the simultaneous detection of multi-angle wavefronts, and realizes the simultaneous measurement of wavefront information of light beams of various incident angles in a large field of view.

[0058] The aperture of diaphragm 100 is less than or equal to two-thirds of the effective aperture of lens assembly 200, thereby further limiting the range of incident light and ensuring that light passing through lens assembly 200 is better focused and perpendicularly incident on microlens array 300, thereby improving measurement accuracy and stability. Furthermore, a suitable aperture of diaphragm 100 can reduce interference from stray light and improve the device's signal-to-noise ratio.

[0059] There is no limit on the number of microlens units in the microlens array 300. In a preferred embodiment, the number of microlens units in the x and y directions of the microlens array 300 is between 10 and 100, thereby easily meeting the requirements of different application scenarios while ensuring the accuracy and efficiency of wavefront measurement. Too many or too few microlens units may affect the performance of wavefront measurement. Therefore, keeping the number of microlens units in the x and y directions within the above range can effectively balance measurement accuracy and efficiency.

[0060] In addition, in order to ensure the performance of the wavefront sensing device, the embodiment of the present application also limits the center distance between the microlens array 300 and the lens group 200 by the spatial sampling rate of the wavefront to be measured.

[0061] It should be noted that the spatial sampling rate is the number of sampling points per unit space (here the number of sub-apertures). The higher the sampling rate, the richer the wavefront details that can be restored.

[0062] Because wavefronts incident at different angles are focused by the lens at different spatial locations on the relay image plane before continuing to propagate forward, simultaneous detection of wavefronts at different angles of incidence is possible. By controlling the spacing between the microlens array 300 and the lens, the number of microlens arrays 300 covered by the wavefront incident at each angle can be controlled, thereby varying the spatial sampling rate of the wavefront being measured.

[0063] When the spatial sampling rate is high, a smaller center-to-center spacing is required to ensure that each microlens unit can accurately capture wavefront information, thereby improving measurement accuracy. Conversely, when the spatial sampling rate is low, the center-to-center spacing can be appropriately increased to reduce the cost and complexity of the device.

[0064] Therefore, the higher the spatial sampling rate, the smaller the center distance between the microlens array 300 and the lens group 200; the lower the spatial sampling rate, the larger the center distance between the microlens array 300 and the lens group 200.

[0065] In a specific implementation, lens assembly 200 may include at least one collimating lens for collimating the incident wavefront into parallel light, thereby better cooperating with microlens array 300 for wavefront measurement. Furthermore, photosensor 400 may utilize a high-precision image acquisition device such as a CCD camera or CMOS sensor to ensure accurate capture of the position and shape of the focused light spot.

[0066] The wide-angle wavefront sensing device provided by the present invention achieves high-precision wavefront measurement over a wide field of view through the ingenious design of the aperture 100 and lens assembly 200, as well as the rational configuration of the microlens array 300 and photoelectric sensor 400. This device not only boasts a simple structure and strong robustness, but also effectively addresses the problems of detection failure and reduced accuracy faced by traditional wavefront sensors at wide angles of incidence, thus possessing broad application prospects.

[0067] Example 1:

[0068] The commercial Shack-Hartmann wavefront sensor can still work at large angles of incidence, but the measurement is inaccurate due to problems such as oblique incidence aberrations or the local wavefront exceeding the microlens field of view of the microlens array.

[0069] Wavefronts incident at large angles deviate significantly from the paraxial condition when passing through the microlens. The resulting focused spot contains significant aberrations, resulting in an irregular spot shape. This affects the algorithm's judgment of the local wavefront slope and severely affects the accuracy of the reconstructed wavefront. The following is a comparison of the reconstruction results of the proposed device and a commercial Shack-Hartmann wavefront sensor for large-angle incident wavefronts.

[0070] Figure 2 is the incident wavefront to be measured (i.e., the maximum field of view of the commercial Shack-Hartmann wavefront sensor).

[0071] Figure 3 This is the incident wavefront after removing the first three terms of the Zernike polynomial (corresponding to the constant term offset and the tilt along the x and y directions, which do not affect the wavefront aberration).

[0072] Figure 4 Comparison of the input and reconstructed Zernike polynomial coefficients of the proposed device at large angle of incidence (removing the first three terms of the Zernike polynomial). It can be seen that the reconstructed Zernike polynomial coefficients are basically consistent with the input Zernike polynomial coefficients.

[0073] Figure 5 is the wavefront reconstructed according to the Zernike polynomial coefficients reconstructed by the proposed device (the first three terms of the Zernike polynomial are removed).

[0074] Figure 6 Comparison of the input and reconstructed Zernike polynomial coefficients of a commercial Shack-Hartmann wavefront sensor at large angles of incidence (removing the first three terms of the Zernike polynomial). It can be seen that the reconstructed Zernike polynomial coefficients are quite different from the input Zernike polynomial coefficients.

[0075] Figure 7 is the wavefront reconstructed based on the Zernike polynomial coefficients of the commercial Shack-Hartmann wavefront sensor (removing the first three terms of the Zernike polynomial), and Figure 3 The incident wavefront has a large difference. This case shows that the proposed wide-angle wavefront sensing device has higher detection accuracy than traditional devices for wavefronts incident at a certain angle.

[0076] Example 2: When the incident light is incident at a larger angle, the traditional Shack-Hartmann wavefront sensor cannot obtain data, while the wide-angle wavefront sensor device proposed in this application can measure normally. Specifically:

[0077] At a larger angle of incidence, such as Figure 8 As shown in the figure (with an incident angle of 15°), for a commercial Shack-Hartmann wavefront sensor, the light spot moves into the area of ​​the adjacent sub-aperture or even completely moves out of the effective area of ​​the detector. At this time, the relationship between the light spot and the microlens cannot be effectively established, resulting in disordered or even lost wavefront information.

[0078] However, for the wide-viewing angle wavefront sensing device proposed in this application, Figure 1 As shown, large-angle wavefronts are converted into normally incident wavefronts, so the subsequent microlens array and sensor can effectively detect the incident wavefront.

[0079] Figure 9Comparing the input and reconstructed Zernike polynomial coefficients of the wide-angle wavefront sensing device proposed in this application at a larger angle of incidence (removing the first three terms of the Zernike polynomial), it can be seen that the reconstructed Zernike polynomial coefficients are basically consistent with the input Zernike polynomial coefficients.

[0080] Figure 10 The wide-angle incident wavefront is reconstructed based on the Zernike polynomial coefficients reconstructed by the wide-angle wavefront sensing device proposed in this application (the first three terms of the Zernike polynomial are removed), so that the wide-angle wavefront sensing device proposed in this application can still maintain high-precision wavefront measurement results at large angles of incidence.

[0081] Example 3: The traditional Shack-Hartmann wavefront sensor can only measure one field of view, while the wide-viewing angle wavefront sensor device proposed in this application can measure multiple fields of view simultaneously.

[0082] The commercial Shack-Hartmann wavefront sensor can only measure one field of view at a time, but for the wide-angle wavefront sensing device proposed in this application, Figure 1 As shown, wavefronts incident at different angles will be focused by the lens at different spatial positions on the relay image plane and then continue to propagate forward, thereby enabling simultaneous detection of wavefronts at different incident angles.

[0083] The wide-angle wavefront sensing device proposed in the present application can realize the detection and effective recovery of incident wavefronts at large angles, and therefore has a large angle detection range. The angle of the incident wavefront that can be detected is only determined by the effective field of view of the lens group 200 that constitutes the image-side telecentric optical path, and can realize the detection of incident wavefronts at large angles of 30° or even more than 50°, while the existing wavefront sensing technology can only realize the detection of incident wavefronts of about 1°. Therefore, the wide-angle wavefront sensing device proposed in the present application has a much larger detection range than the existing technical solutions.

[0084] In the above embodiments, the lenses and microlens arrays are refractive elements. In other embodiments, other elements that can achieve the functions of lenses and microlens arrays, such as reflective elements or diffractive elements, can be used. Furthermore, to achieve a thinner and lighter structure, polarization optical elements can be incorporated to reduce system size, such as pancake lenses, to achieve a more compact image-side telecentric optical path.

[0085] At the same time, an object-image conjugation system can be added between the microlens array and the photosensor. This system is used to ensure that the image formed by the microlens array maintains a conjugate relationship with the image on the photosensor. By adding the object-image conjugation system, the optical path design can be further optimized, and the accuracy and stability of wavefront measurement can be improved. This system may include additional lenses, reflectors, or other optical elements to precisely adjust the propagation path and imaging position of the light, and can also change the number of photosensor pixels covered by each microlens to adjust the spatial resolution of the wavefront sensor.

[0086] In the embodiments of this application, Figure 11 As shown, a wavefront aberration detection method using the wide-viewing angle wavefront sensing device in any of the above embodiments is also provided, comprising:

[0087] Step 101: Compare the centroid position of the focused light spot corresponding to each incident wavefront received by the photoelectric sensor with the centroid position of the reference light spot to obtain the slope information of each incident wavefront in two orthogonal directions; wherein the centroid position of the reference light spot is the centroid position of the standard light spot when there is no aberration.

[0088] Step 102: Fit the slope information into a Zernike polynomial, and reconstruct the complete phase distribution of each incident wavefront according to the Zernike polynomial.

[0089] The spot position is mainly determined by the centroid position of the spot, which is calculated using an adaptive threshold centroid algorithm. The centroid position of the spot under all microlenses on the sensor is compared with the centroid position of the standard spot without aberration (reference plane wave), and the slope of the wavefront in each sub-aperture in two orthogonal directions (X, Y) is obtained, namely:

[0090]

[0091] Where, 、 are the slopes of the wavefront in the sub-aperture in the X and Y axis directions, 、 are the position offsets of the wavefront in the sub-aperture in the X and Y axis directions, is the focal length of the microlens.

[0092] The slope data is then fitted into a Zernike polynomial using a mathematical algorithm (such as the least squares method). (The Zernike polynomial is a mathematical polynomial defined in a polar coordinate system and is a common method for describing wavefront aberrations. For the Shack-Hartmann wavefront sensor, the Zernike polynomial coefficients of the wavefront can be obtained by fitting the measured slope with the derivative of the Zernike polynomial averaged over the sampling subaperture.) The Zernike polynomial expression is:

[0093]

[0094] Where, represents the wavefront phase distribution function described by the Zernike polynomial expansion, is the coefficient of the kth Zernike polynomial term, is the kth Zernike polynomial basis function, and n is the total number of expansion terms.

[0095] By measuring the slope data of a large number of quantum apertures, the coefficients of the Zernike polynomials of various orders can be inferred by solving the linear equations of "slope-coefficient". , the coefficients of each order Zernike polynomial By substituting it into the Zernike polynomial expression, the wavefront phase can be calculated point by point and the incident wavefront phase distribution map can be reconstructed.

[0096] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A wide-viewing angle wavefront sensing device, characterized in that: include: An aperture, a lens group, a microlens array and a photoelectric sensor are sequentially arranged along the direction of the entrance pupil light; The aperture is located at the object focus of the lens group; The photoelectric sensor is located on the focal plane of the microlens array; The microlens array comprises a plurality of identical microlens units arranged at a certain period in a plane; After a plurality of incident wavefronts at different angles are incident through the aperture and refracted by the lens group, the main light rays of each refracted incident wavefront are perpendicularly incident on the plane of the microlens array, and are split by the microlens array and propagate forward, forming focused light spots corresponding to each incident wavefront on the photoelectric sensor.

2. The wide-viewing angle wavefront sensing device according to claim 1, wherein: The aperture of the aperture is less than or equal to two-thirds of the effective light aperture of the lens group.

3. The wide-viewing angle wavefront sensing device according to claim 1, wherein: The number of microlens units in the microlens array in the x and y directions is between 10 and 100.

4. The wide-viewing angle wavefront sensing device according to claim 1, wherein: Also includes: The center distance between the microlens array and the lens group is limited by the spatial sampling rate of the wavefront to be measured.

5. The wide-viewing angle wavefront sensing device according to claim 4, wherein: The higher the spatial sampling rate, the smaller the center distance between the microlens array and the lens group; the lower the spatial sampling rate, the larger the center distance between the microlens array and the lens group.

6. The wide-viewing angle wavefront sensing device according to claim 1, wherein: The lens group includes at least one collimating lens.

7. The wide-viewing angle wavefront sensing device according to claim 1, wherein: The photoelectric sensor is a CCD camera or a CMOS sensor.

8. The wide-viewing angle wavefront sensing device according to any one of claims 1 to 7, wherein: An object-image conjugate system is arranged on the optical path between the photoelectric sensor and the microlens array.

9. A wavefront aberration detection method using the wide-viewing angle wavefront sensing device according to any one of claims 1 to 8, characterized in that: include: The slope information of each incident wavefront in two orthogonal directions is obtained by comparing the centroid position of the focused light spot corresponding to each incident wavefront received by the photoelectric sensor with the centroid position of the reference light spot; wherein the centroid position of the reference light spot is the centroid position of the standard light spot when there is no aberration; The slope information is fitted into a Zernike polynomial, and the complete phase distribution of each incident wavefront is reconstructed according to the Zernike polynomial.

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