Computer-generated holographic element, clamping device and detection system

Abstract

The embodiment of the utility model provides a computer-generated hologram element, a clamping device and a detection system. The computer-generated hologram element comprises a first holographic area, a second holographic area and a third holographic area, the first holographic area, the second holographic area and the third holographic area are formed on at least one of the first side and the second side of the computer-generated hologram element, and the first side and the second side are the two opposite sides of the computer-generated hologram element in the thickness direction; the first holographic region is constructed as a reflective grating and can reflect a first spherical wave incident to the first holographic region from the first side along an original optical path; the second holographic region is constructed as a transmission-type grating, and can transmit a first spherical wave which is incident to the second holographic region from the first side from the second side and convert the first spherical wave into a plane wave; the third holographic area is constructed to be a transmission-type grating which can transmit a first spherical wave incident to the third holographic area from the first side from the second side and convert the first spherical wave into a second spherical wave with a convergence focus.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the field of optical technology, and in particular to a computer generated holographic element, a clamping device, and a detection system. Background Art

[0002] Currently, computer-generated holography (CGH) is often used to inspect aspheric components. Using CGH for aspheric inspection offers advantages such as high precision and minimal design errors. Furthermore, it is a non-contact measurement method, ensuring no scratches are caused on the aspheric component being tested, and the entire surface can be measured. However, CGH inspection of aspheric surfaces requires high alignment accuracy for the entire inspection system. Excessive alignment errors can lead to significant measurement errors. Therefore, there is a need to effectively improve the alignment and inspection accuracy of aspheric component inspection systems. Utility Model Content

[0003] According to a first aspect of the embodiments of the present disclosure, a computer-generated holographic element is provided, comprising: a first holographic region, a second holographic region, and a third holographic region, wherein the first holographic region, the second holographic region, and the third holographic region are all formed on at least one of a first side and a second side of the computer-generated holographic element, and the first side and the second side are two opposite sides of the computer-generated holographic element along the thickness direction; the first holographic region is constructed as a reflection grating, capable of reflecting a first spherical wave incident from the first side to the first holographic region along the original optical path; the second holographic region is constructed as a transmission grating, capable of transmitting from the second side the first spherical wave incident from the first side to the second holographic region and converting it into a plane wave; the third holographic region is constructed as a transmission grating, capable of transmitting from the second side the first spherical wave incident from the first side to the third holographic region and converting it into a second spherical wave having a convergence point.

[0004] According to a second aspect of the embodiments of the present disclosure, a clamping device is provided, comprising: a clamping mechanism and a mirror reflection mechanism; the clamping mechanism is constructed to be able to clamp an aspheric element to be measured, and comprises a bearing surface capable of bearing the aspheric element to be measured when clamping the aspheric element to be measured; the mirror reflection mechanism is arranged on the clamping mechanism, and is used for mirror-reflecting a plane wave transmitted and converted by the second holographic region of the computer-generated holographic element provided according to the first aspect; wherein the mirror reflection mechanism satisfies any of the following conditions: the reflection surface of the mirror reflection mechanism is parallel to the bearing surface; the reflection surface of the mirror reflection mechanism is coplanar with the bearing surface.

[0005] According to a third aspect of the embodiments of the present disclosure, a detection system is provided for detecting an aspheric element to be tested, the detection system comprising: an interferometer, a computer-generated hologram element as provided in the first aspect, and a clamping device as provided in the second aspect, which are arranged in sequence; wherein the clamping device is used to clamp the aspheric element to be tested; the interferometer is used to emit a first spherical wave to the computer-generated hologram element, and the interferometer is further used to: receive first interference light generated by first return light reflected from the first holographic area and a reference light of the interferometer to form first interference fringes; receive second interference light generated by second return light transmitted through the second holographic area, reflected by a mirror reflection mechanism, and then transmitted through the second holographic area, and a reference line of the interferometer to form second interference fringes; receive third interference light generated by third return light transmitted through the third holographic area, reflected by the aspheric element to be tested, and then transmitted through the third holographic area, and the reference light of the interferometer to form third interference fringes. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In order to more clearly illustrate the embodiments of the present disclosure 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 recorded in the embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0007] Figure 1 Schematic diagrams of some exemplary detection systems in the embodiments of the present disclosure.

[0008] Figure 2 Schematic diagrams of some exemplary computer-generated holographic elements in the embodiments of the present disclosure.

[0009] Figure 3 Schematic diagrams of some exemplary clamping devices in embodiments of the present disclosure.

[0010] Figure 4 Flowchart of some exemplary aspheric element detection methods in the embodiments of the present disclosure.

[0011] Figure 5 This is a schematic diagram of measuring the vertex position of the aspheric element to be measured in a tilted state and a non-tilted state.

[0012] Figure 6 It is an optional flowchart of step S406 in the embodiment of the present disclosure.

[0013] Figure 7 It is an optional flowchart of step S4061 in the embodiment of the present disclosure.

[0014] Figure 8 Schematic diagram of the path for scanning the vertex position along a plane orthogonal to the axial direction of the interferometer in an embodiment of the present disclosure.

[0015] Description of reference numerals:

[0016] 10. Aspheric element to be measured; 100. Computer-generated holographic element; 110. First holographic region; 120. Second holographic region; 130. Third holographic region; 140. Fourth holographic region; 200. Clamping device; 210. Clamping mechanism; 220. Mirror reflection mechanism; 300. Interferometer; 310. Standard spherical mirror; 400. Detection system. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field should fall within the scope of protection of the embodiments of the present disclosure. It should be understood that the various steps recorded in the method implementation mode of the present disclosure can be performed in different orders and / or in parallel. In addition, the method implementation mode may include additional steps and / or omit the steps shown. The scope of the present disclosure is not limited in this respect.

[0018] At present, Computer Generated Holography (CGH) elements are often used to detect aspheric components. Using CGH elements for aspheric detection has the advantages of high precision and small design residuals, and it is a non-contact measurement, so the aspheric component to be tested is not scratched and the entire surface to be tested can be measured. However, when using CGH elements for aspheric detection, high requirements are placed on the assembly and adjustment accuracy of the entire detection system. If the assembly and adjustment error is too large, it will cause a large measurement error. In particular, when the central surface symmetry of the aspheric component is poor, it is difficult to adjust the tilt and eccentricity of the aspheric component, and the assembly and adjustment error is also likely to become larger, which has a greater impact on the measurement error. Therefore, it is necessary to effectively improve the equipment assembly and detection accuracy of the detection system for aspheric components.

[0019] The technical solution of the embodiment of the present disclosure is described below in conjunction with the accompanying drawings. It should be noted that, in order to facilitate the description of the embodiment of the present disclosure, the various drawings of the embodiment of the present disclosure are not necessarily drawn according to the actual proportions. They are only used to facilitate the explanation of the technical solution and are not used to impose any restrictions on the embodiment of the present disclosure.

[0020] Some embodiments of the present disclosure provide a detection system for detecting the optical surface of an optical element. The detection system 400 includes: an interferometer 300, a computer-generated holographic element 100, and a clamping device 200, which are arranged in sequence. The clamping device 200 is used to clamp the optical element to be measured. The interferometer 300 is used to emit a first measurement light and a reference light. The first measurement light emitted by the interferometer 300 is transformed into a second measurement light with a set wavefront by the computer-generated holographic element 100, wherein at least part of the second measurement light is incident on the surface to be measured of the aspheric element to be measured 10. After being transmitted or reflected by the surface to be measured of the aspheric element to be measured 10, part of the second measurement light interferes with the reference light emitted by the interferometer 300 to form interference light. The interferometer 300 receives the interference light and forms interference fringes. The interference fringes can reflect the surface shape of the optical surface of the optical element to be measured.

[0021] Figure 1 Schematic diagrams of some exemplary detection systems in the embodiments of the present disclosure are shown. Figure 1 As shown, a detection system 400 is used to detect aspheric components. The detection system 400 includes an interferometer 300, a CGH element 100, and a clamping device 200, which are arranged in sequence. The clamping device 200 is used to clamp the aspheric component 10 to be tested. The interferometer 300 is used to emit first measurement light and reference light toward the CGH element 100. After passing through the CGH element 100, the first measurement light is transformed into second measurement light with a predetermined wavefront. At least a portion of the second measurement light is incident on the surface to be tested of the aspheric component 10 to be tested. After being transmitted or reflected by the surface to be tested of the aspheric component 10 to be tested, a portion of the second measurement light interferes with the reference light emitted by the interferometer 300, forming interference fringes.

[0022] Figure 2 Schematic diagrams showing some exemplary computer generated holographic elements in the embodiments of the present disclosure. Figure 2 As shown, the CGE element 100 provided by some embodiments of the present disclosure includes: a first holographic region 110, a second holographic region 120 and a third holographic region 130, and the first holographic region 110, the second holographic region 120 and the third holographic region 130 are all formed on at least one of the first side and the second side of the CGE element 100, and the first side and the second side are two opposite sides of the CGE element 100 along the thickness direction.

[0023] For example, Figure 1Taking the detection system 400 as an example, the first and second sides of the CGH element 100 are shown. The first and second sides of the CGH element 100 are opposite sides of the CGH element 100 along the thickness direction. In one embodiment, when using the CGH element 100 to detect aspheric components, the first side of the CGH element 100 can be oriented toward the interferometer 300 of the detection system 400. This allows the interferometer 300 to emit first measurement light toward the first side of the CGH element 100, which is then transformed after reflection and / or transmission by the CGH element 100. This can be used in the equipment assembly and detection process for aspheric component detection.

[0024] Optionally, refer to Figure 1 As shown, the interferometer 300 of the detection system 400 may include a standard spherical mirror 310 . The interferometer 300 uses the standard spherical mirror 310 so that the first measurement light emitted outward is a first spherical wave.

[0025] In some embodiments of the present disclosure, the first holographic region 110 may be configured as a reflective grating, capable of reflecting the first spherical wave incident on the first holographic region 110 from the first side along the original optical path.

[0026] Optionally, the first holographic region 110 may also be referred to as an alignment holographic region, which may be used to assist in adjusting the position and tilt of the CGE 100 relative to the standard spherical mirror 310 of the interferometer 300, so as to align the optical axis of the CGE 100 with the optical axis of the standard spherical mirror 310.

[0027] Alternatively, the first holographic region 110 may be configured as an amplitude-type reflective grating.

[0028] Optionally, during the equipment adjustment phase for aspheric component testing, the interferometer 300 emits a first spherical wave toward the first side of the CGE 100 via the standard spherical mirror 310. The first spherical wave is incident on the first holographic region 110 from the first side. The first holographic region 110, with its reflective grating structure, reflects the incident first spherical wave, causing the reflected first return light to return to the interferometer 300 along the original optical path. The first return light interferes with the reference light within the interferometer 300, generating first interference light and forming first interference fringes. Based on the state of the first interference fringes, the detection system 400 can be adjusted to conveniently adjust the position and tilt of the CGE 100 relative to the standard spherical mirror 310 of the interferometer 300, so that the optical axis of the CGE 100 is aligned with the optical axis of the interferometer 300, facilitating accurate aspheric component testing.

[0029] It should be understood that the specific structure and specific location of the first holographic area 110 are not limited in the embodiment of the present disclosure. Figure 2 In the example of the CGH element 100, the first holographic region 110 may be annular. The annular first holographic region 110 may receive and reflect the first spherical wave more uniformly, so as to improve the equipment adjustment effect and the detection effect when detecting the aspheric element.

[0030] In some embodiments of the present disclosure, the second holographic region 120 may be configured as a transmission grating, capable of transmitting a first spherical wave incident on the second holographic region 120 from a first side through a second side and converting the first spherical wave into a plane wave.

[0031] Optionally, the second holographic region 120 can also be called a plane wave holographic region, which can be used to assist in adjusting the tilt of the aspheric element to be measured relative to the interferometer 300, and align the optical axis of the aspheric element to be measured 10 with the optical axis of the interferometer 300 and the optical axis of the CGH element 100.

[0032] Optionally, during the equipment assembly phase for aspheric component testing, the interferometer 300 emits a first spherical wave toward the first side of the CGE 100 via the standard spherical mirror 310. The first spherical wave is incident from the first side onto the second holographic region 120. The second holographic region 120, with its transmissive grating structure, transmits the incident first spherical wave from the second side of the CGE 100 and converts it into a plane wave. The plane wave is then reflected by the mirror reflection mechanism 220 (described in detail below and omitted here) on the clamping device 200 and then transmitted through the second holographic region 120, forming a second return light. The second return light then returns to the interferometer 300, where it interferes with the reference light within the interferometer 300, generating a second interference light that forms a second interference fringe. According to the state of the second interference fringes, the tilt state of the aspheric element 10 to be tested relative to the interferometer 300 can be adjusted so that the optical axis of the aspheric element 10 to be tested is aligned with the optical axis of the interferometer 300 and the optical axis of the CGH element 100, so as to facilitate accurate aspheric element detection.

[0033] When using the CGI element 100 of the disclosed embodiment, when adjusting the tilt of the aspheric element 10 to be tested relative to the interferometer 300, the second holographic region 120 and the mirror reflection mechanism 220 of the clamping device 200 can be used in conjunction with each other. The second return light generated by the first plane wave interferes with the reference light inside the interferometer 300 to form second interference fringes, and then adjustments are made based on the second interference fringes. Therefore, the adjustment speed and adjustment accuracy of the aspheric element can be effectively improved. The disclosed embodiment is also suitable for adjusting the tilt and eccentricity of aspheric elements with asymmetric central surfaces, thereby facilitating the reduction of equipment adjustment errors and improving the detection accuracy of aspheric elements.

[0034] It should be understood that the specific structure and specific location of the second holographic area 120 are not limited in the embodiment of the present disclosure. Figure 2 In the example of the CGH element 100, the second holographic region 120 may be in the shape of a rounded rectangle, or in a regular shape such as a rectangle or a circle, or in other irregular shapes.

[0035] Optionally, refer to Figure 2 As shown, the second holographic area 120 may be located on at least one of the first holographic area 110 and the third holographic area 130. In this way, the volume of the CGE 100 may be reduced without affecting the functions of the first holographic area 110 and the third holographic area 130.

[0036] Alternatively, the second holographic region 120 of the CGE 100 may be single. Alternatively, referring to Figure 2 As shown, the second holographic region 120 of the CGI element 100 may include a plurality of second holographic regions 120, and the plurality of second holographic regions 120 may be arranged at intervals on at least one of the first holographic region 110 and the third holographic region 130. Figure 2 As shown, in this example, the CGH element 100 includes two second holographic regions 120. Optionally, the plurality of second holographic regions 120 may be uniformly arranged on at least one of the first holographic region 110 and the third holographic region 130. Figure 2 As shown, the plurality of second holographic areas 120 may be evenly arranged on the first holographic area 110 and the third holographic area 130. Figure 2 As shown, the second holographic regions 120 are spaced apart around the optical axis of the CGH element 100. Figure 2 As shown, the multiple second holographic regions 120 have the same shape and are evenly spaced around the optical axis of the CGH element 100. It should be understood that the multiple second holographic regions 120 can also have different shapes as long as they meet the needs of use. In the disclosed embodiment, the use of multiple second holographic regions 120 can further improve the equipment assembly accuracy of the detection system 400, thereby facilitating more accurate aspheric component detection.

[0037] In some embodiments of the present disclosure, the third holographic area 130 may be constructed as a transmission grating, capable of transmitting a first spherical wave incident on the third holographic area 130 from a first side through a second side and converting the first spherical wave into a second spherical wave having a focal point.

[0038] Optionally, the third holographic region 130 may also be referred to as a cat's eye holographic region, which may be used to test the vertex position of the aspheric element and assist in adjusting the axial distance from the vertex position of the aspheric element to the CGH element 100 .

[0039] Optionally, during the equipment assembly phase for aspheric component testing, the interferometer 300 emits a first spherical wave toward the first side of the CGE 100 via the standard spherical mirror 310. The first spherical wave is incident from the first side onto the third holographic region 130. The third holographic region 130, with its transmissive grating structure, transmits the incident first spherical wave from the second side of the CGE 100 and converts it into a second spherical wave with a focal point. The second spherical wave is reflected by the aspheric component to be tested and then transmitted through the third holographic region 130, forming a third return light. The third return light returns to the interferometer 300, where it interferes with the reference light within the interferometer 300, generating a third interference light and forming a third interference fringe. The axial distance between the aspheric component to be tested and the CGE 100 can be adjusted based on the state of the third interference fringe to facilitate detection of the vertex of the aspheric component to be tested.

[0040] It should be understood that the specific structure and specific location of the third holographic area 130 are not limited in the embodiment of the present disclosure. Figure 2 In the example of the CGH element 100, the third holographic region 130 may be annular, and the annular third holographic region 130 may be more conducive to receiving and transmitting the first spherical wave, so as to improve the equipment adjustment effect and the detection effect when detecting the aspheric element.

[0041] Based on this, the optional CGH element 100 in the disclosed embodiments, when used in a detection system for an aspheric component to be tested, can assist in the equipment adjustment of the detection system through its first holographic region 110, second holographic region 120, and third holographic region 130, thereby improving the equipment adjustment accuracy and subsequently improving the detection accuracy of the aspheric component to be tested. Furthermore, the CGH element can be effectively applied to the detection of various aspheric components with symmetrical or asymmetrical surface shapes, and can achieve high accuracy.

[0042] In some optional embodiments, the computer-generated holographic element 100 further includes a fourth holographic region 140, which is formed on at least one of the first side and the second side; the fourth holographic region 140 can be constructed as a transmission grating, and can transmit the first spherical wave incident from the first side to the fourth holographic region 140 from the second side and convert it into a preset standard aspherical wave.

[0043] Optionally, the fourth holographic region 140 may also be referred to as a main holographic region, which, during aspheric element testing, may be used to generate a preset standard aspheric wave for performing zero-position interference on the aspheric element 10 to be tested, thereby facilitating interference testing of the aspheric element 10 to be tested. For example, zero-position interference testing may be performed on the aspheric element to be tested.

[0044] Optionally, when testing an aspheric element, the interferometer 300 emits a first spherical wave toward the first side of the CGE 100 via the standard spherical mirror 310. The first spherical wave is transmitted from the first side to the fourth holographic region 140. The fourth holographic region 140, with its transmission grating structure, transmits the incident first spherical wave from the second side of the CGE 100 and converts it into a preset standard aspheric wave. The preset standard aspheric wave is then reflected by the aspheric element to be tested. The light reflected back to the fourth holographic region 140 is then transmitted by the fourth holographic region 140, forming a fourth return light. The fourth return light returns to the interferometer 300 and interferes with the reference light within the interferometer 300, generating a fourth interference light, thereby forming a fourth interference fringe. Based on the state of the fourth interference fringe, interferometric testing (e.g., zero-position interferometric testing) can be performed on the aspheric element 10 to be tested.

[0045] Based on this, the fourth holographic region 140 in the disclosed embodiment enables the CGE 100 to effectively perform interferometric detection on the aspheric element 10 to be tested. Furthermore, taking the detection system 400 as an example, the detection accuracy of the fourth holographic region 140 is not only related to the accuracy of its own aspheric wave generation, but also to the relative position of the CGE 100 and the standard spherical mirror 310 of the interferometer 300, and the relative position of the CGE 100 and the aspheric element 10 to be tested. Because the first holographic region 110 and the second holographic region 120 in the disclosed embodiment can effectively improve the alignment accuracy of these two relative positions, the CGE 100 in the disclosed embodiment can effectively improve the detection accuracy of the fourth holographic region 140, provided that the accuracy of the aspheric wave generation of the fourth holographic region 140 remains constant, thereby achieving more accurate interferometric detection of the aspheric element 10 to be tested.

[0046] It should be understood that the specific structure and specific location of the fourth holographic area 140 are not limited in the embodiment of the present disclosure. Figure 2 In the example of the CGH element 100, the fourth holographic region 140 may be circular, or may be a regular shape such as a square, or may be other irregular shapes.

[0047] In some optional embodiments, referring to Figure 2 In the example of FIG. 1 , the first holographic area 110 and the third holographic area 130 are both annular and arranged around the outer side of the fourth holographic area 140 , and the second holographic area 120 is located on at least one of the first holographic area 110 and the third holographic area 130 .

[0048] Optionally, the first holographic area 110 and the third holographic area 130 may be Figure 2The circular ring shape shown and described above may also be a ring of other shapes, such as a rectangular ring, an oblong ring, etc.

[0049] Optionally, refer to Figure 2 For example, the fourth hologram area 140 is circular, the first hologram area 110 can be arranged around the outside of the fourth hologram area 140 , and the third hologram area 130 can be arranged around the outside of the first hologram area 110 .

[0050] In some other optional embodiments, the fourth holographic area 140 is circular, the third holographic area 130 can be arranged around the outside of the fourth holographic area 140 , and the first holographic area 110 can be arranged around the outside of the third holographic area 130 .

[0051] It should be understood that the embodiment of the present disclosure does not impose specific restrictions on the annular zone widths of the first holographic area 110 and the third holographic area 130. When necessary, the annular zone width of the third holographic area 130 can be set slightly larger to improve the detection accuracy of the aspheric component to be tested through the third holographic area 130. This is because the detection accuracy of the third holographic area 130 in the axial direction (i.e., the optical axis direction) can be understood as shown in the following formula:

[0052]

[0053] Where z is the axial position error, Δw is the peak-to-valley (PV) value of the wavefront of the third interference light that forms the third interference fringes, and F is the F-number of the beam of the preset standard aspheric wave transmitted by the third holographic area 130. If Δw remains unchanged, increasing the annular band width of the third holographic area 130, i.e., reducing F, will reduce the axial position error z of the third holographic area 130. The smaller the position error, the higher the detection accuracy of the axial position. Therefore, the annular band width of the third holographic area 130 can be set as large as possible to improve the detection accuracy of the aspheric component to be tested through the third holographic area 130.

[0054] Based on this, in the embodiment of the present disclosure, by arranging the first holographic region 110 and the third holographic region 130 to be annularly arranged outside the fourth holographic region 140, and arranging the second holographic region 120 on at least one of the first holographic region 110 and the third holographic region 130, on the one hand, the structure of the CGE 100 is made more compact without affecting the function of the CGE 100; on the other hand, it is more conducive to receiving and transmitting the first spherical wave, so as to improve the equipment adjustment effect and the detection effect when detecting the aspheric element; on the other hand, the other holographic regions do not interfere with the fourth holographic region 140 used for interference detection, so as to achieve more accurate interference detection of the aspheric element 10 to be detected.

[0055] Next, the clamping device 200 will be described. Figure 3 Schematic diagrams of some exemplary clamping devices in the embodiments of the present disclosure are shown. Figure 3 As shown, the CGH element 100 provided in some embodiments of the present disclosure includes: a clamping mechanism 210 and a mirror reflection mechanism 220. The clamping mechanism 210 can be constructed to be able to clamp the aspheric element 10 to be measured, and includes a bearing surface that can bear the aspheric element 10 to be measured when clamping the aspheric element 10 to be measured. Optionally, the mirror reflection mechanism 220 can be arranged around the clamping mechanism 210, or can be arranged on the bearing surface of the clamping mechanism 210. The mirror reflection mechanism 220 is used to mirror-reflect the plane wave transmitted and converted by the second holographic region 120 of the CGH element 100 provided in any of the above embodiments; wherein the mirror reflection mechanism 220 satisfies any of the following conditions: the reflection surface of the mirror reflection mechanism 220 is parallel to the bearing surface; the reflection surface of the mirror reflection mechanism 220 is coplanar with the bearing surface.

[0056] Based on this, the clamping device 200 can support the aspheric element 10 to be tested via the supporting surface of the clamping mechanism 210, and can mirror-reflect the plane wave transmitted and converted by the second holographic region 120 of the CGE element 100 via the reflective surface of the mirror reflector 220, which is parallel to or coplanar with the supporting surface, so as to facilitate accurate and convenient equipment alignment using the second holographic region 120. Therefore, the use of the clamping device 200 in conjunction with the CGE element 100 can effectively assist in the equipment alignment of the detection system, improve the equipment alignment accuracy, and thus subsequently improve the detection accuracy of the aspheric element to be tested.

[0057] When using the clamping device 200 of the disclosed embodiment to adjust the tilt of the aspheric element 10 to be measured relative to the interferometer 300, the second holographic region 120 of the CGH element 100 and the mirror reflection mechanism 220 of the clamping device 200 can be used in conjunction with each other. The second return light generated by the first plane wave interferes with the reference light within the interferometer 300 to form second interference fringes, which are then used to make adjustments. Furthermore, this solution is effectively applicable to adjusting the tilt and decentering of aspheric elements with asymmetric central surfaces, facilitating the reduction of equipment alignment errors, reducing measurement errors, and improving detection accuracy.

[0058] In some embodiments of the present disclosure, the clamping mechanism 210 has a bearing surface. When clamping the aspheric element to be measured 10, the aspheric element to be measured 10 is placed against the bearing surface of the clamping mechanism 210. At this time, it is considered that the optical axis of the aspheric element to be measured is perpendicular to the bearing surface. When adjusting the position of the clamping device 200 thereafter, it is necessary to ensure that the relative position of the aspheric element to be measured 10 and the bearing surface remains unchanged. In this way, when the tilt state of the aspheric element to be measured is adjusted according to the second interference fringe, after the reflection surface of the mirror reflection mechanism 220 is perpendicular to the optical axis of the CGH element 100, the optical axis of the aspheric element to be measured 10 is aligned with the optical axis of the interferometer 300 and the optical axis of the CGH element 100.

[0059] Combine Figure 1 Taking the detection system 400 shown as an example, the mirror reflection mechanism 220 can mirror-reflect the plane wave transmitted and converted by the second holographic region 120 of the CGH element 100. The plane wave is mirror-reflected by the mirror reflection mechanism 220 and then transmitted by the second holographic region 120, forming a second return light that returns to the interferometer 300. The second return light interferes with the reference light within the interferometer 300, generating a second interference light that forms a second interference fringes. By adjusting the position of the clamping device 200 based on the second interference fringes, the tilt of the aspheric element 10 to be tested relative to the interferometer 300 can be conveniently and effectively adjusted, so that the optical axis of the aspheric element 10 to be tested is aligned with the optical axis of the interferometer 300 and the optical axis of the CGH element 100, facilitating accurate aspheric element testing.

[0060] In some optional embodiments, the position where the mirror reflection mechanism 220 is arranged on the clamping device 200 corresponds to the position where the second holographic region 120 is arranged on the CGH element 100 .

[0061] It should be understood that one way to understand the position correspondence in the embodiment of the present disclosure can be: the projection of the second holographic area 120 onto the clamping device 200 is at least partially located in the area where the mirror reflection mechanism 220 on the clamping device 200 is located.

[0062] Based on this, the clamping device 200 in the above-mentioned optional embodiment ensures that the plane waves reflected by the mirror reflection mechanism 220 are reflected back to the second holographic region 120 as much as possible by aligning the position of the mirror reflection mechanism 220 on the clamping device 200 with the position of the second holographic region 120 on the CGH element 100. In this way, the clamping device 200 and the CGH element 100 are used in conjunction to facilitate adjustment of the tilt state of the optical axis of the aspheric element to be tested, improve the equipment assembly accuracy, and thus facilitate subsequent improvement in the detection accuracy of the aspheric element to be tested.

[0063] Optionally, the projection of the second holographic area 120 toward the mirror reflection mechanism 220 is located within the area where the mirror reflection mechanism 220 is located.

[0064] The specific structure of the mirror reflection mechanism 220 is not limited in the embodiments of the present disclosure. For example, the mirror reflection mechanism 220 may include an independent plane mirror structure having a reflective surface to achieve mirror reflection. For another example, the mirror reflection mechanism 220 may also include structures such as a mirror reflection coating or a mirror reflection film. Both the mirror reflection coating and the mirror reflection film can form a reflective surface to achieve mirror reflection. The mirror reflection coating and the mirror reflection film can be made of any coating material or film material that meets the requirements.

[0065] Alternatively, in the case where the reflective surface of the mirror reflective mechanism 220 is parallel to the supporting surface, the mirror reflective mechanism 220 can be mounted on the clamping mechanism 210 such that the reflective surface is higher or lower relative to the supporting surface in a direction perpendicular to the supporting surface. In this manner, if the mirror reflective mechanism 220 employs an independent plane mirror structure, this can be achieved by properly positioning the plane mirror; if the mirror reflective mechanism 220 employs a structure such as a mirror reflective coating or a mirror reflective film, the mirror reflective coating or film can be properly positioned on another surface of the clamping mechanism 210 that is parallel to the supporting surface and higher or lower than the supporting surface.

[0066] Optionally, for the method in which the reflective surface of the mirror reflection mechanism 220 is coplanar with the bearing surface, the mirror reflection mechanism 220 can be installed on the bearing surface of the clamping mechanism 210. In this method, if the mirror reflection mechanism 220 adopts an independent plane mirror structure, it can be achieved by reasonably setting the position of the plane mirror (for example, in addition to being able to reasonably install it on other structures on the clamping mechanism 210 so that the reflective surface of the plane mirror is coplanar with the bearing surface, in some other methods, a groove can also be dug on the bearing surface and the plane mirror can be embedded in the groove so that the reflective surface of the plane mirror is coplanar with the bearing surface); if the mirror reflection mechanism 220 adopts a structure such as a mirror reflection coating or a mirror reflection film, the mirror reflection coating, the mirror reflection film, etc. can be reasonably set on the clamping mechanism 210 (for example, a mirror reflection coating can be applied on the bearing surface or a mirror reflection film can be set). Alternatively, the mirror reflection mechanism 220 can also be set on other surfaces on the clamping mechanism 210 that are coplanar with the bearing surface).

[0067] It should be understood that the mirror reflective mechanism 220 can be mounted on the clamping mechanism 210 in any manner as long as it meets the requirements, such as by bonding, coating, etc.

[0068] In the embodiment of the present disclosure, the shape of the mirror reflection mechanism 220 is not specifically limited. Figure 3In the example shown, the shape may be a rounded rectangle, or a regular shape such as a rectangle or a circle, or other irregular shapes.

[0069] Optionally, refer to Figure 3 In the example shown, the clamping device 200 may include a plurality of mirror reflection mechanisms 220 to adapt to the plurality of second holographic regions 120 of the CGH element 100. Figure 2 As shown, in this example, the clamping device 200 may include two mirror reflection mechanisms 220. Optionally, the positions at which the multiple mirror reflection mechanisms 220 are arranged on the clamping device 200 correspond to the positions at which the multiple second holographic regions 120 are arranged on the CGH element 100. It should be understood that the multiple mirror reflection mechanisms 220 may adopt the same structure or different structures, as long as they can meet the needs of use. In the embodiment of the present disclosure, the clamping device 200 adopts multiple mirror reflection mechanisms 220 to adapt to the multiple second holographic regions 120 of the CGH element 100 to achieve coordinated use, which can more effectively improve the equipment assembly accuracy of the detection system 400, so as to facilitate more accurate aspheric element detection.

[0070] The detection system 400 is described in detail below.

[0071] In the detection system 400, the interferometer 300 can be any suitable interferometer. Figure 1 As shown, the interferometer 300 of the detection system 400 may include a standard spherical mirror 310 , and the interferometer 300 may emit a first spherical wave to the CGH element 100 through the standard spherical mirror 310 .

[0072] In the detection system 400, the clamping mechanism 210 of the clamping device 200 can clamp the component under test. The component under test can be an aspheric component 10. The aspheric component 10 is placed against the supporting surface of the clamping mechanism 210, so that the supporting surface supports the aspheric component 10. When the aspheric component 10 is supported by the supporting surface, the optical axis of the aspheric component 10 is perpendicular to the supporting surface.

[0073] In the detection system 400 , the first spherical wave emitted by the interferometer 300 enters the first holographic region 110 , the second holographic region 120 , and the third holographic region 130 of the CGH element 100 from the first side of the CGH element 100 .

[0074] In the detection system 400 , the interferometer 300 further receives first interference light generated by the first return light reflected by the first holographic region 110 and the reference light of the interferometer 300 , thereby forming first interference fringes.

[0075] Optionally, the first spherical wave emitted by the interferometer 300 is transmitted from the first side of the CGE 100 to the first holographic region 110. The first holographic region 110, having a reflective grating structure, reflects the incident first spherical wave, causing the reflected first return light to return to the interferometer 300 along the original optical path. The first return light interferes with the reference light within the interferometer 300, generating first interference light. The interferometer 300 receives the first interference light, forming first interference fringes. During the equipment adjustment phase for aspheric component detection using the detection system 400, the detection system 400 can be adjusted based on the state of the first interference fringes to conveniently adjust the position and tilt of the CGE 100 relative to the standard spherical mirror 310 of the interferometer 300, so that the optical axis of the CGE 100 is aligned with the optical axis of the interferometer 300, thereby facilitating accurate aspheric component detection.

[0076] In the detection system 400, the interferometer 300 also receives second interference light generated by the second return light transmitted by the second holographic area 120, reflected by the mirror reflection mechanism 220, and then transmitted by the second holographic area 120 and the reference light of the interferometer 300, forming second interference fringes.

[0077] Optionally, the first spherical wave emitted by the interferometer 300 is incident on the second holographic region 120 from the first side of the CGE 100. The second holographic region 120, with its transmissive grating structure, transmits the incident first spherical wave from the second side of the CGE 100 and converts it into a plane wave. The plane wave is then reflected back to the second holographic region by the mirror reflection mechanism 220 on the clamping device 200. The light reflected back to the second holographic region 120 is then transmitted through the second holographic region 120, forming a second return light. The second return light returns to the interferometer 300, where it interferes with the reference light within the interferometer 300, generating a second interference light. The interferometer 300 receives the second interference light, forming a second interference fringes. Based on the state of the second interference fringes, the tilt of the aspheric component 10 to be tested relative to the interferometer 300 can be adjusted to ensure that the optical axis of the aspheric component 10 to be tested is aligned with the optical axes of the interferometer 300 and the CGE 100, thereby facilitating accurate aspheric component testing.

[0078] In the detection system 400, the interferometer 300 also receives third interference light generated by the third return light transmitted by the third holographic area 130, reflected by the aspheric element 10 to be tested, and then transmitted by the third holographic area 130 and the reference light of the interferometer 300, forming third interference fringes.

[0079] Optionally, the first spherical wave emitted by the interferometer 300 is incident on the third holographic region 130 from the first side of the CGH element 100. The third holographic region 130, with its transmissive grating structure, transmits the incident first spherical wave from the second side of the CGH element 100 and converts it into a second spherical wave with a focal point. The second spherical wave can be reflected by the aspheric element to be tested. The light reflected back to the third holographic region 130 is then transmitted through the third holographic region 130, forming a third return light. The third return light returns to the interferometer 300 and interferes with the reference light within the interferometer 300, generating a third interference light. The interferometer 300 receives the third interference light, forming a third interference fringe. During the equipment assembly phase for aspheric element testing using the detection system 400, the axial distance between the aspheric element to be tested 10 and the CGH element 100 can be adjusted based on the state of the third interference fringe to facilitate detection of the vertex of the aspheric element to be tested.

[0080] Based on this, the detection system 400 of the above embodiment emits a first spherical wave through the interferometer 300 and receives: first interference fringes formed by first interference light generated by first return light reflected from the first holographic region of the CGE 100 and the reference light of the interferometer 300; second interference fringes formed by second interference light generated by second return light transmitted through the second holographic region 120 of the CGE 100, reflected by the mirror reflection mechanism 220 of the clamping device 200 provided in the second aspect, and then transmitted through the second holographic region 120, and the reference light of the interferometer 300; and third interference fringes formed by third interference light generated by third return light transmitted through the third holographic region 130 of the CGE 100, reflected by the aspheric element 10 to be tested, and then transmitted through the third holographic region 130, and the reference light of the interferometer 300. Therefore, based on the first, second, and third interference fringes, a more accurate and convenient equipment adjustment of the detection system for aspheric elements can be achieved, and more accurate aspheric element detection can be performed. Moreover, it can be effectively applied to the detection of various types of aspheric elements with symmetrical or asymmetrical surface shapes, and can achieve high precision.

[0081] In some optional embodiments, the detection system 400 includes the CGH element 100 further comprising a fourth holographic region 140 formed on at least one of the first and second sides of the CGH element 100. The fourth holographic region 140 may be configured as a transmission grating, capable of transmitting a first spherical wave incident on the fourth holographic region 140 from the first side through the second side and converting it into a predetermined standard aspherical wave. Furthermore, the interferometer 300 is further configured to receive fourth interference light generated by fourth return light transmitted through the fourth holographic region 140, reflected by the aspheric element 10 to be tested, and then transmitted through the fourth holographic region, and the interferometer's reference light, thereby forming fourth interference fringes.

[0082] Optionally, the first spherical wave emitted by the interferometer 300 is incident on the fourth holographic region 140 from the first side of the CGE 100. The fourth holographic region 140, with its transmission grating structure, transmits the incident first spherical wave from the second side of the CGE 100 and converts it into a preset standard aspherical wave. The preset standard aspherical wave can be reflected by the aspheric element to be measured. The light reflected back to the fourth holographic region 140 is then transmitted by the fourth holographic region 140 to form fourth return light. The fourth return light returns to the interferometer 300 and interferes with the reference light within the interferometer 300, generating fourth interference light. The interferometer 300 receives the fourth interference light, forming fourth interference fringes. Based on the state of the fourth interference fringes, interferometric detection (e.g., zero-position interferometric detection) can be performed on the aspheric element to be measured.

[0083] The fourth holographic region 140 has been described in detail in the embodiment of the CGH element 100 above, which can be understood by referring to the above and will not be described again here.

[0084] Based on this, in the above-mentioned detection system 400, the interferometer 300 receives the fourth interference fringes formed by the fourth interference light generated by the fourth return light transmitted by the fourth holographic area 140, reflected by the aspheric element 10 to be tested, and then transmitted by the fourth holographic area and the reference light of the interferometer 300, thereby realizing interference detection of the aspheric element 10 to be tested.

[0085] Optionally, when the detection system 400 according to the embodiment of the present disclosure is used to detect the aspheric element 10 to be detected, in one application scenario, the vertex position of the aspheric element 10 to be detected may be detected.

[0086] In order to facilitate understanding of the usage of the detection system 400 in the embodiments of the present disclosure, the detection method of the detection system 400 in some embodiments of the present disclosure will be described below. Figure 4 Flowcharts of some exemplary aspheric element detection methods in the embodiments of the present disclosure. The aspheric element detection methods provided in some embodiments of the present disclosure use the detection system 400 provided in the above embodiments. Figure 4 As shown, the aspheric element detection method includes steps S402, S404 and S406, specifically:

[0087] S402: Adjust at least one of the position and posture of the CGE relative to the interferometer until the first interference fringe meets a first condition, so as to adjust the CGE to a preset position.

[0088] Reference Figure 1In the detection system 400 shown, during the assembly and adjustment phase of the detection system 400, the interferometer 300 is started to continuously emit first spherical waves to the CGH element 100. Based on the above description, the interferometer 300 can obtain first interference fringes. At this stage, at least one of the position and posture of the CGH element 100 relative to the interferometer 300 can be adjusted until the first interference fringes meet the first condition, thereby adjusting the CGH element 100 to a preset position.

[0089] Optionally, the first condition may be a condition for determining whether the first interference fringes have achieved a desired flatness and sparseness. In some optional embodiments, step S402 may include adjusting at least one of the position and posture of the CGE element relative to the interferometer until the first interference fringes are straight and the number of fringes is within a predetermined number, thereby adjusting the CGE element 100 to a preset position. At this point, the first interference fringes are considered to have achieved a flatness and sparseness. At this preset position, the optical axis of the CGE element 100 is aligned with the optical axis of the interferometer 300 and there is no defocus aberration. The position and tilt of the CGE element 100 relative to the standard spherical mirror 310 of the interferometer 300 can be considered to have been adjusted. The predetermined number of fringes can be selected based on required accuracy, for example, it can be less than or equal to two, for example, two or one. This helps ensure the accuracy of equipment assembly and the detection accuracy of aspheric elements.

[0090] S404: Adjusting the posture of the clamping device until the second interference fringes meet the second condition, so that the optical axis of the aspheric element to be measured on the clamping device is aligned with the optical axis of the interferometer.

[0091] Reference Figure 1 In the illustrated detection system 400, during the assembly phase, the interferometer 300 continuously emits a first spherical wave toward the CGH element 100. Based on the above description, the interferometer 300 can generate second interference fringes. During this phase, the position of the clamping device 200 can be adjusted until the second interference fringes meet the second condition, thereby aligning the optical axis of the aspheric element 10 to be tested, located on the clamping device 200, with the optical axis of the interferometer 300.

[0092] In some optional embodiments, step S404 may include: adjusting the posture of the clamping device 200 until the second interference fringe presents a zero fringe state, so that the optical axis of the aspheric element to be measured 10 located on the clamping device 200 is aligned with the optical axis of the interferometer 300.

[0093] When the second interference fringe appears to be zero, the reflective surface of the mirror reflection mechanism 220 of the clamping device 200 and the optical axis of the CGH element 100 are considered perpendicular to each other. Because the reflective surface is parallel or coplanar with the supporting surface of the clamping mechanism 210, and the optical axis of the aspheric element 10 to be tested is perpendicular to the supporting surface, the optical axis of the aspheric element 10 to be tested, located on the clamping device 200, is now aligned with the optical axis of the CGH element 100 and the optical axis of the interferometer 300. The tilt of the aspheric element 10 to be tested relative to the interferometer 300 can be considered to have been adjusted, facilitating the subsequent equipment assembly and aspheric element testing.

[0094] Based on this, the embodiment of the present disclosure can effectively align the optical axis of the aspheric element 10 to be tested located on the clamping device 200 with the optical axis of the interferometer 300 by adjusting the posture of the clamping device 200 until the second interference fringe presents a zero fringe state, thereby facilitating the adjustment of the tilt of the aspheric element 10 to be tested relative to the CGH element 100, which is beneficial to improving the detection accuracy of the aspheric element.

[0095] Reference Figure 5 As shown, it shows a schematic diagram of measuring the vertex position of the aspheric element 10 to be measured in a tilted state and a non-tilted state (that is, the optical axis of the aspheric element 10 to be measured is aligned with the optical axis of the interferometer 300). Figure 5 As shown in FIG. 1 , OA represents the optical axis of the interferometer 300; the solid line represents the non-tilted state of the aspheric element 10 to be measured, and A represents the vertex position in the non-tilted state; the dotted line represents the tilted state of the aspheric element 10 to be measured, and A' represents the vertex position in the tilted state. In the non-tilted state, the vertex position A of the aspheric element can be easily found by scanning using the convergence point formed by the third holographic region 130 of the CGH element 100. In the tilted state, it is difficult to accurately find the vertex position A' by scanning using the convergence point formed by the third holographic region 130 (it should be understood that Figure 5 Point A' is located on the dotted line. Because the tilted state introduces coma and astigmatism, resulting in significant test errors, it becomes difficult to detect the vertex position of the aspheric element 10 under test. Therefore, aligning the optical axes of the interferometer 300, the CGH element 100, and the aspheric element 10 under test through steps S402 and S404 in the disclosed embodiment is an important means of improving the vertex detection accuracy of aspheric elements.

[0096] S406: Adjust the position of the clamping device until the third interference fringe meets the third condition, so as to determine the vertex position of the aspheric element to be measured.

[0097] Reference Figure 1In the detection system 400 shown, during testing, the interferometer 300 continuously emits the first spherical wave to the CGH element 100. Based on the above description, the interferometer 300 can obtain third interference fringes. At this stage, the posture of the clamping device 200 can be adjusted until the third interference fringes meet the third condition, so as to accurately determine the vertex position on the aspheric element 10 to be tested.

[0098] In some alternative embodiments, reference Figure 6 In the flowchart shown, step S406 may include the following steps S4061 and S4062, specifically:

[0099] S4061: Adjust the position of the clamping device until the third interference fringe is the sparsest;

[0100] S4062: Determine the position of the convergence point of the second spherical wave on the aspheric element to be measured when the third interference fringes are the sparsest as the vertex position of the aspheric element to be measured.

[0101] According to the characteristics of an aspheric surface, the vertex of the aspheric surface is an extreme point. When the convergence point of the second spherical wave transmitted and converted by the third holographic region 130 coincides with the vertex position of the aspheric element 10 to be tested, the sparsest third interference fringes are obtained. Therefore, the above-mentioned optional implementation scheme of the disclosed embodiment adjusts the position of the clamping device 200 to find the position of the convergence point of the second spherical wave on the aspheric element to be tested when the third interference fringes are sparsest. This position is determined as the vertex position of the aspheric element 10 to be tested, thereby effectively detecting the vertex position of the aspheric element and ensuring the accuracy of the test results.

[0102] The specific method of adjusting the position of the clamping device 200 until the third interference fringes are the most sparse in step S4061 is not limited in the embodiment of the present disclosure.

[0103] In some alternative embodiments, reference Figure 7 In the flowchart shown, step S4061 may include the following steps S4061A to S4061C, specifically:

[0104] S4061A: Adjust the position of the clamping device along the axial direction of the interferometer until the third interference fringe is the sparsest during the adjustment process along the axial direction of the interferometer.

[0105] To accurately locate the vertex position of the aspheric element 10 to be measured, it is necessary to determine the vertex position from three directions in space (e.g., the first direction, the second direction, and the third direction, which are considered to be the x, y, and z directions, respectively, and the three directions are perpendicular to each other). The axial direction (i.e., the optical axis direction) of the interferometer 300 can be defined as the third direction. By adjusting the position of the clamping device 200 along the axial direction (i.e., the third direction) of the interferometer 300, the position where the third interference fringe is most sparse during the adjustment process along the axial direction of the interferometer 300 is found, and the position of the vertex position of the aspheric element 10 to be measured along the axial direction (i.e., the third direction) of the interferometer 300 is determined. Afterwards, this position can be used as a reference to continue detecting the vertex position in several other directions (i.e., the first direction and the second direction).

[0106] The plane orthogonal to the z direction (ie, the axial direction of the interferometer 300 ), that is, the plane formed by the first direction and the second direction, can then be scanned along a cross within the plane to find the vertex positions in the first direction and the second direction.

[0107] S4061B: In a plane orthogonal to the axial direction of the interferometer, adjust the position of the clamping device along the first direction until the third interference fringe is the sparsest during the adjustment process in the first direction.

[0108] For example, refer to Figure 8 As shown, the first direction is the direction of path 1. The position of the clamping device 200 can be adjusted multiple times along path 1, so that the focal point of the second spherical wave transmitted and converted by the third holographic region 130 of the CGH element 100 scans the aspheric element 10 to be tested along path 1 until the position where the third interference fringes are the sparsest during the adjustment process in the first direction is found. It should be understood that Figure 8 Path 1 shown in FIG is only an example for ease of understanding.

[0109] S4061C: In a plane orthogonal to the axial direction of the interferometer, adjust the position of the clamping device along a second direction perpendicular to the first direction until the third interference fringe is the sparsest during the adjustment process in the second direction.

[0110] For example, refer to Figure 8 As shown, the second direction is the direction of path 2. The position of the clamping device 200 can be adjusted multiple times along path 2, so that the convergence point of the second spherical wave transmitted and converted by the third holographic region 130 of the CGH element 100 scans the aspheric element 10 to be tested along path 2 until the position where the third interference fringes are the sparsest during the adjustment process in the second direction is found. It should be understood that Figure 8 Path 2 shown in FIG is only an example for ease of understanding.

[0111] It should be noted that the order of steps S4061B and S4062C can be arbitrarily selected, and can be S4061B first and S4062C second, or S4061C first and S4061B second. For example, taking S4061B first and S4062C second as an example, after S4061B finds the position where the third interference fringes are most sparse during the adjustment process in the first direction, this position is used as a reference, and then S4061C is performed. That is, using this reference position as the foot of the vertical, the position of the clamping device 200 is adjusted in a second direction perpendicular to the first direction until the position where the third interference fringes are most sparse during the adjustment process in the second direction is found. The position where the third interference fringes are most sparse during the adjustment process in the second direction is thus found. Thus, the position of the convergence point of the second spherical wave on the aspheric component to be measured when the third interference fringes are most sparse can be determined as the vertex position of the aspheric component to be measured. For another example, taking S4061C as the first step and S4061B as the second step, after S4061C finds the position where the third interference fringes are most sparse during the adjustment process in the second direction, this position can be used as a reference and then S4061B can be performed. That is, using this reference position as the foot of the vertical, the position of the clamping device 200 is adjusted along the first direction perpendicular to the second direction until the position where the third interference fringes are most sparse during the adjustment process in the first direction is found. The position where the third interference fringes are most sparse during the adjustment process in the first direction is thus found. In this way, the position of the convergence point of the second spherical wave on the aspheric component to be measured when the third interference fringes are most sparse can be determined as the vertex position of the aspheric component to be measured.

[0112] Optionally, the above steps S4061A to S4061C may be performed multiple times to further improve the detection accuracy of the vertex position of the aspheric element 10 to be tested.

[0113] Based on this, in the embodiment of the present disclosure, through the optional implementation of the above steps S4061A to S4061C, the position of the clamping device is adjusted along the axial direction of the interferometer so that the third interference fringes are sparsest during the adjustment process along the axial direction of the interferometer. In a plane orthogonal to the axial direction of the interferometer, the position of the clamping device is then adjusted along the first direction and the second direction respectively until the third interference fringes are sparsest. This allows the position where the third interference fringes are sparsest to be accurately and effectively determined, and thus the vertex position of the aspheric element 10 to be measured can be determined based on the position of the convergence point of the second spherical wave on the aspheric element to be measured when the third interference fringes are sparsest. This ensures the accuracy of the detection result of the vertex position of the aspheric element, and improves the detection precision.

[0114] It should be understood that the aspheric component detection method of steps S402 to S406 of the present embodiment can conveniently and accurately achieve equipment adjustment and facilitate precise detection of the vertex position of the aspheric component 10 to be tested, thereby improving detection accuracy. Furthermore, it can be effectively applied to the detection of various aspheric components with symmetrical or asymmetrical surface shapes, and can achieve high accuracy.

[0115] In addition, the aspheric surface detection method of the embodiment of the present disclosure is a non-contact interference detection method, which can also reduce the damage to the surface of the aspheric surface element 10 to be tested.

[0116] It will be understood that the above descriptions of various aspects of the embodiments of the present disclosure are merely some optional exemplary descriptions of the technical solutions of the embodiments of the present disclosure, and are not intended to limit the embodiments of the present disclosure.

[0117] The above describes in detail the optional implementation methods of the embodiments of the present disclosure in conjunction with the accompanying drawings, but the embodiments of the present disclosure are not limited thereto. Within the technical concept of the embodiments of the present disclosure, a variety of simple variations can be made to the technical solutions of the embodiments of the present disclosure. The various technical features included in the different embodiments of the embodiments of the present disclosure can be combined in any suitable manner. In order to avoid unnecessary repetition, the embodiments of the present disclosure will not be further described in detail for various possible combinations. However, these simple variations and combinations should also be regarded as the contents disclosed by the embodiments of the present disclosure, and all belong to the protection scope of the embodiments of the present disclosure.

[0118] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". It should be noted that the concepts of "first", "second", etc. mentioned in the embodiments of the present disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units. It should be noted that the modifications of "one" and "multiple" mentioned in the embodiments of the present disclosure are illustrative rather than restrictive. Those skilled in the art should understand that unless the context clearly indicates otherwise, it should be understood as "one or more".

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present disclosure, rather than to limit them. Although the embodiments of the present disclosure have 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 embodiments of the present disclosure.

Claims

1. A computer generated holographic element, comprising: a first holographic region, a second holographic region, and a third holographic region, wherein the first holographic region, the second holographic region, and the third holographic region are all formed on at least one of a first side and a second side of the CGH element, the first side and the second side being opposite sides of the CGH element along a thickness direction; The first holographic region is constructed as a reflective grating, capable of reflecting the first spherical wave incident on the first holographic region from the first side along the original optical path; The second holographic region is constructed as a transmission grating, capable of transmitting the first spherical wave incident on the second holographic region from the first side through the second side and converting it into a plane wave; The third holographic region is constructed as a transmission grating, capable of transmitting the first spherical wave incident on the third holographic region from the first side through the second side and converting the first spherical wave into a second spherical wave having a focal point.

2. The CGH element according to claim 1, wherein: The CGH element further includes a fourth holographic region formed on at least one of the first side and the second side; The fourth holographic region is constructed as a transmission grating and is capable of transmitting the first spherical wave incident on the fourth holographic region from the first side through the second side and converting the first spherical wave into a preset standard aspherical wave.

3. The CGH element according to claim 2, wherein: The first holographic area and the third holographic area are both annular and arranged around the outside of the fourth holographic area. The second holographic area is located on at least one of the first holographic area and the third holographic area.

4. A clamping device comprising: A clamping mechanism is configured to clamp the aspheric element to be tested, and includes a bearing surface capable of bearing the aspheric element to be tested when clamping the aspheric element to be tested; a mirror reflection mechanism, arranged on the clamping mechanism, for mirror-reflecting the plane wave transmitted and converted by the second holographic region of the CGH element according to any one of claims 1 to 3; Wherein, the mirror reflection mechanism meets any of the following conditions: The reflecting surface of the mirror reflection mechanism is parallel to the carrying surface; The reflection surface of the mirror reflection mechanism is coplanar with the bearing surface.

5. The clamping device according to claim 4, wherein: The position where the mirror reflection mechanism is arranged on the clamping device corresponds to the position where the second holographic region is arranged on the CGH element.

6. A detection system for detecting an aspheric element to be detected, the detection system comprising: An interferometer, a computer generated holographic element according to any one of claims 1 to 3, and a clamping device according to claim 4 or 5, which are arranged in sequence; The clamping device is used to clamp the aspheric element to be measured; the interferometer is used to emit a first spherical wave to the computer generated hologram element, and the interferometer is further used to: receiving first interference light generated by first return light reflected from the first holographic area and reference light of the interferometer to form first interference fringes; receiving second interference light generated by the second return light transmitted by the second holographic area, reflected by the mirror reflection mechanism, and then transmitted by the second holographic area and the reference line of the interferometer to form second interference fringes; A third interference light generated by the third return light transmitted by the third holographic area, reflected by the aspheric element to be measured, and then transmitted by the third holographic area and the reference light of the interferometer is received to form third interference fringes.

7. The detection system according to claim 6, wherein: The CGH element further includes a fourth holographic region formed on at least one of the first side and the second side; The fourth holographic region is constructed as a transmission grating, and is capable of transmitting the first spherical wave incident on the fourth holographic region from the first side through the second side and converting it into a preset standard aspherical wave; The interferometer is further configured to receive fourth interference light generated by fourth return light transmitted by the fourth holographic area, reflected by the aspheric element to be measured, and then transmitted by the fourth holographic area and the reference light of the interferometer, to form fourth interference fringes.

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