A large aperture spherical equal thickness optical window detection system and method

Abstract

Embodiments of the present application provide a large-aperture spherical equal-thickness optical window detection system and method for evaluating the surface shape change and the influence on imaging performance of a large-aperture spherical equal-thickness optical window to be detected under different installation attitudes, wherein the front and back surfaces of the optical window are concentric spherical surfaces, the aperture is 200 mm to 1000 mm, and the surface F number is 0.3 to 10. The system comprises a cassette plus compensation mirror assembly, the cassette plus compensation mirror assembly comprising a Cassegrain system, first, second and third compensation mirrors arranged in sequence along the optical axis and passing through the center hole of the primary mirror, and a detector assembly. Light passes through the optical window, then passes through the primary mirror, the secondary mirror and the third compensation mirror in sequence, and is finally received by the detector assembly for imaging. Then, the imaging performance of the large-aperture spherical equal-thickness optical window to be detected is evaluated based on the optical signal received by the detector assembly.

Description

Technical Field

[0001] This application relates to the field of optical inspection technology, and in particular to a large-aperture spherical equal-thickness optical window inspection system and method. Background Technology

[0002] With the widespread application of airborne optoelectronic equipment in the aviation field, optical windows (or simply windows) are crucial components. They not only protect internal optoelectronic devices from external environmental influences but also must meet the requirements of the aircraft's overall aerodynamic shape and structural layout. Based on these practical application needs, spherical windows are widely used due to their excellent aerodynamic performance and wide field-of-view imaging capabilities. In practical applications, because spherical windows participate in the optical path design of the imaging system, high requirements are placed on their imaging performance.

[0003] A large-aperture spherical constant-thickness optical window refers to a spherical crown-shaped optical window with a window diameter greater than or equal to 200 mm and less than or equal to 1000 mm, a surface F-number greater than or equal to 0.3 and less than or equal to 10, uniform curvature on both the front and back surfaces, and uniform overall wall thickness. When a large-aperture spherical constant-thickness optical window participates in system imaging, it introduces spherical aberration and chromatic aberration. Furthermore, due to its weight, it can cause significant gravity-induced surface deformation under certain installation orientations, leading to additional astigmatism and affecting the imaging quality of the system. In practical applications, large-aperture spherical constant-thickness optical windows are often placed vertically or at an angle to the horizontal plane.

[0004] In related technologies, imaging performance is evaluated by detecting the surface shape of a large-aperture spherical window of uniform thickness. For example, a laser profilometer can be used to detect the surface shape of a horizontally placed window under test. However, for windows that are placed vertically or at an angle to the horizontal plane during application, there is a problem that the window placement during surface shape detection is inconsistent with the actual placement in application, resulting in measurement results that cannot accurately reflect surface shape changes under working conditions. Alternatively, an interferometer can be used with a standard lens matched to the radius of curvature of the window under test to detect the surface shape of a vertically placed window under test. Specifically, the detection beam is converged and aberrations are compensated to ensure that the detection beam is perpendicularly incident on the surface of the window under test for surface shape detection. However, currently, there is no suitable standard lens for large-aperture spherical windows of uniform thickness, therefore, surface shape detection is not possible.

[0005] Therefore, there is an urgent need to provide a solution that can perform surface shape detection on large-aperture spherical windows of equal thickness at different installation angles in order to accurately evaluate their imaging performance under actual working conditions. Summary of the Invention

[0006] This application provides a detection system and method for a large-aperture spherical equal-thickness optical window, used to detect the surface shape of a large-aperture spherical equal-thickness optical window at different installation angles and evaluate its imaging performance under actual working conditions.

[0007] In a first aspect, embodiments of this application provide a detection system for a large-aperture spherical equal-thickness optical window, used to detect the imaging performance of a large-aperture spherical optical window to be detected. The front and rear surfaces of the large-aperture spherical equal-thickness optical window to be detected are concentric spheres. The surface F-number of the large-aperture spherical optical window to be detected is F, and the window diameter is D1, satisfying the following relationships: 0.3≤F≤10, 200mm≤D1≤1000mm. The system includes: A Cassegrain compensation mirror assembly, comprising: a Cassegrain system, a compensation mirror, and a detector assembly; The Cassegrain system includes a primary mirror and a secondary mirror. The primary mirror and the secondary mirror form an image independently. The primary mirror and the secondary mirror are coaxially positioned. The aperture of the primary mirror is D2, and the aperture of the secondary mirror is D3. The obstruction ratio of the primary and secondary mirrors is D3 / D2. The combined focal length of the primary mirror and the secondary mirror is f, satisfying the following relationship: 100mm≤D2≤500mm, 0.1≤D3 / D2≤0.6, 100mm≤f≤1000mm; The compensating mirror includes a first compensating mirror, a second compensating mirror, and a third compensating mirror placed coaxially with the secondary mirror. The first compensating mirror, the second compensating mirror, and the third compensating mirror are arranged sequentially along the optical axis and pass through the central hole of the primary mirror. In the process of detecting the large-aperture spherical equal-thickness optical window to be tested, light rays pass sequentially along the incident direction through the large-aperture spherical equal-thickness optical window to be tested, the primary mirror, the secondary mirror, the first compensation mirror, the second compensation mirror, the third compensation mirror, and the detector assembly. The light signal detected by the detector assembly is used to evaluate the imaging performance of the large-aperture spherical equal-thickness optical window to be tested.

[0008] Secondly, embodiments of this application provide a method for detecting large-aperture spherical equal-thickness optical windows, applied to the large-aperture spherical equal-thickness optical window detection system described in the first aspect, the method comprising: The Cassegrain system is assembled and adjusted so that the primary and secondary mirrors of the Cassegrain system are placed coaxially. The positions of the detector assembly and the compensating mirror are determined based on the position of the Cassegrain system. The compensating mirror includes a first compensating mirror, a second compensating mirror, and a third compensating mirror placed coaxially with the secondary mirror. The distance between the primary and secondary mirrors is L1, and the distance between the front surfaces of the first and secondary mirrors is L3, satisfying the relationship: 0.2 ≤ L3 / L1 ≤ 5. The Cassegrain plus compensating mirror assembly, which includes the Cassegrain system, the compensating mirrors, and the detector assembly, shares the same image plane and focal length with the Cassegrain system. The large-diameter spherical equal-thickness optical window to be tested is installed on the load mounting assembly by means of shaft hole fitting and end face positioning, and the load mounting assembly is fixed to the support assembly; The cassette-type compensation lens assembly is installed on the support assembly; wherein, the distance between the concave surface of the large-aperture spherical equal-thickness optical window to be tested and the front surface of the primary mirror is L2, satisfying the relationship: 1.2*L1≤L2≤5*L1; The large-aperture spherical equal-thickness optical window detection system is placed at the center in front of the collimator, which is used to emit the detection beam. The reducer assembly installed on the support assembly controls the load mounting assembly to adjust the pitch angle of the large-aperture spherical equal-thickness optical window to be tested, and to maintain the pitch angle of the large-aperture spherical equal-thickness optical window to be tested. At any pitch angle, the light signal detected by the detector assembly is acquired, and the detected light signal is compared with the ideal imaging result to obtain the imaging performance of the large-aperture spherical equal-thickness optical window under test at any pitch angle.

[0009] The large-aperture spherical equal-thickness optical window detection system provided in this application, by employing a Cassegrain system as the core imaging unit, not only effectively increases the imaging detection range of the large-aperture spherical equal-thickness optical window detection system, but also brings the imaging performance of the large-aperture spherical equal-thickness optical window detection system close to the diffraction limit, significantly improving imaging quality and detection accuracy. Furthermore, the Cassegrain plus compensation mirror assembly includes three levels of compensation mirrors, arranged sequentially along the optical axis and inserted through the central hole of the primary mirror. This allows for precise correction and focusing of the light reflected from the large-aperture spherical equal-thickness optical window under test without disrupting the original optical path, ensuring that the detector receives high-quality interference signals or image information. In addition, when detecting the large-aperture spherical equal-thickness optical window under test using the large-aperture spherical equal-thickness optical window detection system, the placement angle of the large-aperture spherical equal-thickness optical window under test can be customized. Therefore, it is possible to complete the surface shape change measurement of its entire surface under different installation postures to evaluate its imaging performance under different installation postures. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A schematic diagram of a large-aperture spherical equal-thickness optical window detection system provided in an embodiment of this application; Figure 2 A schematic diagram of a large-aperture spherical equal-thickness optical window detection system including mechanical devices provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of a load mounting component provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of a cassette-type compensation lens assembly provided in an embodiment of this application; Figure 5 This is a schematic diagram of the structure of a support component provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a gearbox assembly provided in an embodiment of this application; Figure 7 A flowchart illustrating a method for detecting a large-aperture spherical equal-thickness optical window provided in this application embodiment; Figure 8 This is a schematic diagram illustrating an application scenario for detecting a large-aperture spherical equal-thickness optical window, as provided in an embodiment of this application. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0014] Furthermore, the timing of the steps in the following method embodiments is merely an example and not a strict limitation.

[0015] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0016] To facilitate understanding of the solutions related to the detection of large-aperture spherical equal-thickness optical windows provided in the embodiments of this application, the detection system for large-aperture spherical equal-thickness optical windows provided in the embodiments of this application will be described first, and then the method for detecting large-aperture spherical equal-thickness optical windows based on this system will be described.

[0017] This application provides a large-aperture spherical equal-thickness optical window inspection system for detecting the surface shape of a large-aperture spherical optical window under different installation angles, and evaluating its imaging performance under actual working conditions. Specifically, when inspecting the large-aperture spherical equal-thickness optical window under test using the large-aperture spherical equal-thickness optical window inspection system, the placement angle of the large-aperture spherical equal-thickness optical window under test can be customized and adjusted. Therefore, the surface shape change measurement of its entire surface can be completed under different installation postures to evaluate its imaging performance under different installation postures.

[0018] In this test, the front and rear surfaces of the large-aperture spherical window with uniform thickness are concentric spheres (i.e., their centers are the same). In other words, the large-aperture spherical window with uniform thickness is a spherical crown-shaped optical window with the same curvature on both the front and rear surfaces and uniform overall wall thickness. If the surface F-number of the large-aperture spherical window is denoted as F, and the window diameter is denoted as D1, then the surface F-number F satisfies the relationship: 0.3 ≤ F ≤ 10, and the window diameter D1 satisfies the following relationship: 200 mm ≤ D1 ≤ 1000 mm. For example, the surface F-number of the large-aperture spherical window with uniform thickness 10 is 0.38, and the window diameter D1 is 394 mm.

[0019] It is worth noting that, in the embodiments of this application, for any optical device, the front surface refers to the optical surface on which light first enters under normal working conditions, while the rear surface refers to the optical surface on which light finally exits after passing through the optical device.

[0020] The large-aperture spherical equal-thickness optical window detection system provided in this application includes: a Cassegrain plus compensation mirror assembly. The Cassegrain plus compensation mirror assembly includes: a Cassegrain system, a compensation mirror, and a detector assembly.

[0021] The Cassegrain compensation lens assembly shares the same image plane and focal length as the Cassegrain system.

[0022] The image plane shared by the Cassegrain system and the Cassegrain system refers to the fact that the image plane formed by the Cassegrain system when it images alone is completely coincident in spatial position with the image plane formed by the optical components in the Cassegrain system (i.e., the Cassegrain system + the compensating mirror) when they image as a whole. This ensures that the detector assembly can receive the compensated high-quality image at the same position without having to adjust the detector position due to the introduction of the compensating mirror.

[0023] For ease of understanding, combined with Figure 1 The large-aperture spherical equal-thickness optical window detection system provided in the embodiments of this application will be described by way of example.

[0024] Figure 1 This is a schematic diagram of a large-aperture spherical equal-thickness optical window detection system provided in an embodiment of this application. It is worth noting that... Figure 1 In addition to illustrating the large-aperture spherical equal-thickness light window detection system provided in the embodiments of this application, the large-aperture spherical equal-thickness light window 10 to be detected is further illustrated. The relevant description can be found in the foregoing content. The large-aperture spherical equal-thickness light window detection system will be described in detail below.

[0025] like Figure 1 As shown, the Cassegrain system includes a primary mirror 20 and a secondary mirror 30. Both the primary mirror 20 and the secondary mirror 30 have quadratic surfaces. The primary mirror 20 has a central cavity, and the primary mirror 20 and the secondary mirror 30 are placed coaxially. The primary mirror 20 and the secondary mirror 30 form an image independently; specifically, light can be reflected between the primary mirror 20 and the secondary mirror 30, thus forming a primary image plane behind the primary mirror 20.

[0026] The primary image plane refers to the plane on which the first real image is formed by the Cassegrain system consisting of the primary mirror 20 and the secondary mirror 30 through two-stage reflection without relying on any subsequent optical elements. This image plane is located on the optical axis behind the central hole of the primary mirror and can be used as the input object plane of the subsequent compensation mirror or directly for imaging detection.

[0027] In this embodiment of the application, optionally, the aperture of the primary mirror 20 is denoted as D2, which satisfies the relationship: 100mm≤D2≤500mm.

[0028] The aperture of the secondary mirror 30 is denoted as D3, and the obstruction ratio between the primary and secondary mirrors is denoted as D3 / D2, satisfying the relationship: 0.1≤D3 / D2≤0.6.

[0029] The combined focal length of the primary mirror 20 and the secondary mirror 30 is denoted as f, which satisfies the relationship: 100mm≤f≤1000mm.

[0030] For example, the combined focal length f of the primary lens 20 and the secondary lens 30 is 600mm, the aperture D2 of the primary lens 20 is 154mm, the aperture of the central hole of the primary lens 20 is 48mm, the aperture D3 of the secondary lens 30 is 48mm, and the primary-secondary lens obstruction ratio D3 / D2=48mm / 154mm≈0.311 satisfies the relationship 0.1≤D3 / D2≤0.6.

[0031] Optionally, the primary mirror 20 and the secondary mirror 30 are made of fused silica glass.

[0032] Optionally, the number of compensating lenses in the cassette-type compensating lens assembly can be one or more. In this embodiment, three compensating lenses are used as an example for illustration. Figure 1 As shown, the compensation mirror includes a first compensation mirror 41, a second compensation mirror 42, and a third compensation mirror 43, which are placed coaxially with the secondary mirror 30. The first compensation mirror 41, the second compensation mirror 42, and the third compensation mirror 43 are arranged sequentially along the optical axis and pass through the central hole of the primary mirror 20.

[0033] When testing a large-aperture spherical equal-thickness optical window 10, such as Figure 1 As shown, the light rays are along the incident direction ( Figure 1 The light rays shown in the diagram (incident from left to right) pass sequentially through the large-aperture spherical equal-thickness optical window 10 to be tested, the primary mirror 20, the secondary mirror 30, the first compensation mirror 41, the second compensation mirror 42, the third compensation mirror 43, and the detector assembly 50.

[0034] The detector assembly 50 is used to detect the light signal emitted after passing through the third compensation mirror 43. The detected light signal is used to evaluate the imaging performance of the large-aperture spherical equal-thickness optical window under test. Specifically, by comparing and analyzing the actual light signal detection results with the ideal imaging state, the impact of the surface deformation caused by the optical window's own weight when it is not placed horizontally is quantitatively evaluated on its imaging performance.

[0035] Optionally, the detector assembly 50 is a camera with a resolution of ≥1920*1200 and a pixel size of <6μm. In practical applications, cameras with a resolution of ≥1920*1200 and a pixel size of <6μm are also referred to as high-resolution cameras.

[0036] The large-aperture spherical equal-thickness optical window detection system provided in this application adopts a Cassegrain system as the core imaging unit, enabling both the primary and secondary mirrors to have quadratic curved surfaces and achieving light reflection imaging between them, thereby forming a clear primary image plane behind the primary mirror. The Cassegrain system not only effectively increases the imaging detection range of the large-aperture spherical equal-thickness optical window detection system but also brings its imaging performance close to the diffraction limit, significantly improving imaging quality and detection accuracy. Furthermore, the Cassegrain plus compensation mirror assembly includes three levels of compensation mirrors, arranged sequentially along the optical axis and inserted through the central hole of the primary mirror. This allows for precise correction and focusing of the light reflected from the large-aperture spherical equal-thickness optical window without disrupting the original optical path, ensuring that the detector receives high-quality interference signals or image information. Furthermore, when testing a large-aperture spherical equal-thickness optical window using a large-aperture spherical equal-thickness optical window testing system, the placement angle of the large-aperture spherical equal-thickness optical window can be customized. Therefore, the surface shape change measurement of its entire surface can be completed under different installation postures to evaluate its imaging performance under different installation postures.

[0037] In summary, the large-aperture spherical equal-thickness light window detection system constructed in this application embodiment realizes the transformation from static single-angle detection to dynamic multi-angle detection, breaking through the limitation of traditional detection methods that cannot truly reflect the performance of the light window under working conditions, and has good practicality, accuracy and engineering applicability.

[0038] In an alternative embodiment, Figure 1 The large-aperture spherical equal-thickness optical window detection system shown has a distance L1 between the primary mirror 20 and the secondary mirror 30, a distance L2 between the concave surface of the large-aperture spherical equal-thickness optical window 10 to be detected and the front surface of the primary mirror 20, and a distance L3 between the front surface of the first compensating mirror 41 and the front surface of the secondary mirror 30, satisfying the following relationship: 1.2*L1≤L2≤5*L1; 0.2≤L3 / L1≤5.

[0039] In this embodiment, by setting the range of the distance L2 between the concave surface of the large-aperture spherical equal-thickness optical window 10 to be tested and the front surface of the primary mirror 20, sufficient space is ensured for the large-aperture spherical equal-thickness optical window 10 during installation, preventing physical contact with the secondary mirror 30 and thus preventing measurement errors or equipment damage caused by collisions. Simultaneously, this distance setting also ensures that light can propagate smoothly to the primary mirror 20 and complete reflection imaging. By setting the range of the distance L3 between the front surface of the first compensation mirror 41 and the front surface of the secondary mirror 30, an appropriate distance is maintained between the first compensation mirror 41 and the secondary mirror 30, preventing the first compensation mirror 41 from blocking the incident light while ensuring the compensation mirror's effective correction capability for subsequent beams. Therefore, the constraints of the above-mentioned distance parameters improve the mechanical stability and optical transmission efficiency of the large-aperture spherical equal-thickness optical window detection system, enhance the safety and reliability of the entire detection system in actual operation, and provide a stable optical environment for high-precision surface detection.

[0040] In another alternative embodiment, Figure 1 The schematic large-aperture spherical equal-thickness optical window detection system has a first compensating mirror 41 that is a meniscus lens with its convex surface facing the secondary mirror; a second compensating mirror 42 that is a biconvex lens; and a third compensating mirror 43 that is a biconcave lens. The front surfaces of the first compensating mirror 41 and the second compensating mirror 42 are both aspherical, while the rear surfaces of the first compensating mirror 41, the second compensating mirror 42, the front surface of the third compensating mirror 43, and the rear surface of the third compensating mirror 43 are all spherical.

[0041] In this embodiment, by designing the structure and surface curvature of three compensation mirrors, efficient correction and accurate imaging are achieved for the light transmitted through the large-aperture spherical equal-thickness window 10 and reflected by the secondary mirror 30. Specifically, the first compensation mirror 41 adopts a meniscus lens structure with the convex surface facing the secondary mirror, which can introduce appropriate negative optical power without significantly increasing the length of the large-aperture spherical equal-thickness window detection system, helping to balance the aberrations caused by the combination of the primary mirror 20 and the secondary mirror 30; the second compensation mirror 42 is a biconvex lens, providing the necessary positive optical power for subsequent focusing; the third compensation mirror 43 is a biconcave lens, used to further adjust the beam convergence state and improve the overall imaging quality. In addition, the front surfaces of the first compensation mirror 41 and the second compensation mirror 42 are both aspherical, which can effectively suppress geometric aberrations caused by the large aperture and large field of view, and significantly improve the imaging resolution and contrast of the large-aperture spherical equal-thickness window detection system; while the remaining surfaces of the compensation mirrors are spherical, which can significantly reduce manufacturing difficulty and cost while ensuring optical performance. Therefore, the design of the compensation mirror in this embodiment not only achieves high-precision aberration correction and wide spectral response, but also balances optical performance with engineering implementation, providing a reliable and practical optical solution for high-precision detection of large-aperture spherical equal-thickness windows.

[0042] In another alternative embodiment, phase difference compensation for a large-aperture, equal-thickness optical window to be inspected can be achieved by selecting the material and shape of the compensation mirror, thereby achieving a good chromatic aberration elimination effect.

[0043] For example, the first compensating mirror can be made of low-dispersion, high-refractive-index glass, and the second compensating mirror can be made of high-dispersion flint glass. The two have opposite optical powers and satisfy the achromatic condition: ϕ1 / V1 + ϕ2 / V2 = 0, where ϕ1 is the optical power of the first compensating mirror, ϕ2 is the optical power of the second compensating mirror, V1 is the Abbe number of the first compensating mirror, and V2 is the Abbe number of the second compensating mirror; the third compensating mirror can be made of ultra-low dispersion material.

[0044] In this embodiment, the synergistic design of materials and aspherical shapes enables effective correction of chromatic aberrations across a wide spectral range, thereby improving the imaging quality of multi-band detection.

[0045] The large-aperture spherical equal-thickness optical window detection system provided in the foregoing embodiments achieves high-precision imaging detection of large-aperture spherical equal-thickness optical windows under multi-angle conditions through the coordinated design of the Cassegrain system (i.e., Cassegrain-type optical structure) and the compensating mirror. To ensure the stable operation of this large-aperture spherical equal-thickness optical window detection system in practical application scenarios and to achieve dynamic adjustment and accurate measurement of the large-aperture spherical equal-thickness optical window under different pitch angles, this application embodiment further provides a hand-cranked roll mechanism for... Figure 1 The large-aperture spherical equal-thickness light window detection system shown provides mechanical support and pitch drive.

[0046] Figure 2 This is a schematic diagram of a large-aperture spherical equal-thickness optical window detection system including a mechanical device, provided as an embodiment of this application. Figure 2 As shown, the large-diameter spherical equal-thickness optical window detection system, which includes a hand-cranked rolling mechanism, comprises: a load mounting assembly 1, a cassette compensating mirror assembly 2, a support assembly 3, and a gearbox assembly 4.

[0047] The load mounting component 1 is fixed to the support component 3 by means of screws, corresponding mating relationships (such as threaded connection, stop positioning, keyway mating, pin positioning, or flange face fitting, etc.), and is used to install the large-diameter spherical equal-thickness light window to be tested, and to adjust the pitch angle of the large-diameter spherical equal-thickness light window to be tested.

[0048] Figure 3 This is a schematic diagram of the structure of a load-mounting component provided in an embodiment of this application, as shown below. Figure 3 As shown, the load mounting assembly 1 includes: mounting ring frame 1-1, right pitch bracket 1-2, counterweight 1-3, reinforcing rib 1-4, and left pitch bracket 1-5.

[0049] The mounting ring 1-1 is used to mount the large-diameter spherical equal-thickness optical window to be tested. The left elevation bracket 1-5 and the right elevation bracket 1-2 are fixedly connected to the left and right sides of the mounting ring 1-1, respectively. The two ends of the reinforcing rib 1-4 are connected to the left elevation bracket 1-5 and the right elevation bracket 1-2, respectively. The counterweight 1-3 is fixedly installed on the left elevation bracket 1-5 and the right elevation bracket 1-2 at the ends furthest from the mounting ring 1-1.

[0050] like Figure 3 As shown, the left pitch bracket 1-5 and the right pitch bracket 1-2 are respectively provided with circular holes, which can be used to connect with the bearing assembly on the support assembly 3, thereby realizing the rotation of the load mounting assembly 1 in the pitch direction.

[0051] In the specific implementation process, the pitch angle of the load mounting component 1 can be adjusted by rotating it, thereby adjusting the pitch angle of the large-aperture spherical equal-thickness optical window to be tested. When the load mounting component 1 is rotated, the distance between the rotation center of the load mounting component and the center of the optical window of the large-aperture spherical equal-thickness optical window to be tested is d1, where 100mm ≤ d1 ≤ 1000mm.

[0052] Optionally, the load mounting component 1 can be manufactured as an integrated assembly, thereby ensuring the accuracy of the actual distance between the center of the large-aperture spherical equal-thickness optical window to be tested and the rotation center, and thus ensuring that the center of the optical window of the large-aperture spherical equal-thickness optical window to be tested coincides with the rotation axis during rotation.

[0053] Optionally, the counterweights 1-3 can be adjusted according to the weight of the large-aperture spherical equal-thickness optical window to be tested. For example, when the weight of the large-aperture spherical equal-thickness optical window to be tested is large, a larger counterweight is selected accordingly; when the weight of the large-aperture spherical equal-thickness optical window to be tested is small, a smaller counterweight is selected accordingly. By selecting counterweights 1-3 that are compatible with the weight of the large-aperture spherical equal-thickness optical window to be tested, the large-aperture spherical equal-thickness optical window to be tested and the counterweights 1-3 achieve torque balance in the pitch direction, thereby reducing the operating resistance of adjusting the pitch angle of the large-aperture spherical equal-thickness optical window to be tested through the load mounting components, and improving the stability and convenience of pitch angle adjustment.

[0054] Figure 4 This is a schematic diagram of a cassette-type compensation lens assembly provided in an embodiment of this application. Figure 4 As shown, the cassette-type compensation lens assembly 2 includes: an optical assembly 2-1 and an imaging assembly 2-2.

[0055] Among them, optical component 2-1 refers to the Cassegrain system and compensating mirror described above, and imaging component 2-2 refers to the detector component. For a more detailed introduction to the Cassegrain system and compensating mirror assembly, please refer to [link to relevant information]. Figure 1 The embodiments shown are not described in detail here.

[0056] Figure 5 This is a schematic diagram of a support component provided in an embodiment of this application. Figure 5 As shown, the support assembly 3 includes: a base plate 3-1, a first bearing assembly 3-2, a second bearing assembly 3-3, a gearbox bracket 3-4, a cartridge component bracket 3-5, and a handle 3-6, all mounted on the base plate 3-1.

[0057] The axes of the first bearing assembly 3-2 and the second bearing assembly 3-3 are parallel. Figure 3 The left pitch bracket 1-5 in the load mounting assembly 1 shown is connected to the inner or outer ring of the first bearing assembly 3-2 (through a circular hole on the left pitch bracket 1-5). The right pitch bracket 1-2 is connected to the inner or outer ring of the second bearing assembly 3-3 (through a circular hole on the right pitch bracket 1-2).

[0058] The load mounting assembly 1 rotates based on the first bearing assembly 3-2 and the second bearing assembly 3-3. The center of the concave surface of the large-diameter spherical equal-thickness optical window to be measured is located on the common axis of the first bearing assembly 3-2 and the second bearing assembly 3-3. When the load mounting assembly 1 rotates, it drives the large-diameter spherical equal-thickness optical window to be measured to rotate around the center of the concave surface of the large-diameter spherical equal-thickness optical window to be measured.

[0059] The gearbox bracket 3-4 is used to mount the gearbox assembly 4. The gearbox assembly 4 and the support assembly 3 are fixedly connected via the gearbox bracket 3-4. Optionally, this fixed connection can be achieved through screws, corresponding mating relationships (such as threaded connections, stop-lock positioning, keyway mating, pin positioning, or flange face contact, etc.). The gearbox assembly 4 is connected to the load mounting assembly 1 via a drive shaft, used to control the adjustment of the pitch angle of the large-diameter spherical equal-thickness optical window to be tested by the load mounting assembly 1, and to maintain the pitch angle of the large-diameter spherical equal-thickness optical window to be tested.

[0060] Figure 6 This is a schematic diagram of the structure of a gearbox assembly provided in an embodiment of this application, as shown below. Figure 6 As shown, the gearbox assembly 4 includes: handle 4-1, handwheel 4-2, and gearbox 4-3.

[0061] The gearbox assembly 4 uses a worm gear transmission. The handle 4-1 is fixedly connected to the handwheel 4-2. The handwheel 4-2 is located at the input end of the gearbox 4-3 and is used to receive the rotational torque applied by the operator. The gearbox 4-3 contains a worm and a worm wheel that meshes with it. The worm serves as the input shaft and the worm wheel serves as the output shaft, which is used to convert the high-speed, low-torque input into the low-speed, high-torque output.

[0062] In practice, the output shaft of the gearbox 4-3 is connected to the rotating shaft of the first bearing assembly 3-2, which is connected to the load mounting assembly 1, through the transmission shaft, forming a rigid connection. When the operator turns the handle 4-1, the handwheel 4-2 drives the worm gear to rotate, which in turn drives the worm wheel to output at a lower speed and higher torque, so that the transmission shaft drives the load mounting assembly 1 to adjust the pitch angle.

[0063] During the process of adjusting the pitch angle of the large-aperture spherical equal-thickness optical window to be tested via the reduction gearbox assembly 4 and the load mounting assembly 1, the radius of curvature of the large-aperture spherical equal-thickness optical window to be tested is R, and the vertical rotation range of the pitch angle of the large-aperture spherical equal-thickness optical window to be tested is ≥ Where D1 is the aperture of the large-aperture spherical optical window to be tested, D2 is the aperture of the primary mirror in the Seiglin system, and ≮ indicates not less than.

[0064] Because worm gear transmission has a self-locking characteristic (i.e., it cannot drive the input end in reverse when the output end is subjected to force), after the load mounting component 1 drives the large-diameter spherical equal-thickness light window to be tested to any pitch angle, it can maintain a stable pitch state (i.e., maintain the pitch angle of the large-diameter spherical equal-thickness light window to be tested) without the need for an additional locking device, thus realizing the self-locking function and improving the safety and stability of the testing process.

[0065] Furthermore, the gearbox 4-3 converts high-speed, low-torque manual input into low-speed, high-torque output, significantly reducing the torque requirements applied by the operator. Even when the load mounting components and the mass of the large-diameter spherical equal-thickness optical window to be tested are large, it can easily complete the precise adjustment of the pitch angle of the large-diameter spherical equal-thickness optical window to be tested, effectively improving human-machine interaction efficiency and measurement accuracy.

[0066] Figure 5 The clip-on component bracket 3-5 in the support assembly shown is used to mount the clip-on compensation lens assembly. For example... Figure 5 As shown, the cassette assembly bracket 3-5 is provided with an oblong hole, which is used to allow the cassette assembly with compensation lens to move in both horizontal and vertical directions. Specifically, the horizontal adjustment range of the cassette assembly with compensation lens is ±10mm, and the vertical adjustment range is ±5mm. This oblong hole design enables fine-tuning of the cassette assembly with compensation lens in both horizontal and vertical directions. This not only corrects assembly errors and adapts to large-aperture spherical equal-thickness windows of different sizes to be inspected, but also optimizes image quality, simplifies the debugging process, and improves the flexibility and accuracy of the large-aperture spherical equal-thickness window inspection system.

[0067] Handles 3-6 are used for manual gripping and applying force to move or adjust the position of the entire large-diameter spherical equal-thickness optical window detection system, thereby improving the ease of movement and operational flexibility of the equipment.

[0068] This application utilizes a hand-cranked rolling mechanism to achieve stable adjustment and precise measurement of a large-diameter spherical optical window of equal thickness under multiple pitch angles. The load mounting assembly connects to the support assembly via bearings, and works in conjunction with the worm gear transmission of the reduction gearbox assembly to achieve low-speed, high-torque output and a self-locking function, ensuring smooth and reliable angle adjustment. The counterweight design optimizes torque balance and reduces operating resistance. The slotted hole in the card-type component bracket supports micro-adjustments of ±10mm horizontally and ±5mm vertically, improving system adaptability and imaging accuracy. The handle facilitates overall transport, enhancing equipment portability and operational flexibility.

[0069] The following describes the method for detecting a large-aperture spherical equal-thickness optical window based on the large-aperture spherical equal-thickness optical window detection system provided in the embodiments of this application.

[0070] Figure 7 A flowchart illustrating a method for detecting large-aperture spherical equal-thickness optical windows provided in this application embodiment is applied to the large-aperture spherical equal-thickness optical window detection system described in the foregoing embodiments, such as... Figure 7 As shown, the method includes at least the following steps: 701. Assemble and adjust the Cassegrain system so that the primary and secondary mirrors of the Cassegrain system are placed coaxially, and determine the positions of the detector assembly and the compensating mirror according to the position of the Cassegrain system; wherein, the compensating mirror includes a first compensating mirror, a second compensating mirror, and a third compensating mirror placed coaxially with the secondary mirror, the distance between the primary and secondary mirrors is L1, and the distance between the front surface of the first compensating mirror and the front surface of the secondary mirror is L3, satisfying the relationship: 0.2≤L3 / L1≤5; the Cassegrain plus compensating mirror assembly, which includes the Cassegrain system, the compensating mirror, and the detector assembly, is co-image plane with the Cassegrain system and has the same focal length.

[0071] 702. The large-diameter spherical equal-thickness light window to be tested is installed on the load mounting assembly by means of shaft hole fit and end face positioning. The load mounting assembly is fixed to the support assembly.

[0072] 703. Install the cassette compensation mirror assembly onto the support assembly; wherein, the distance between the concave surface of the large-aperture spherical equal-thickness optical window to be tested and the front surface of the primary mirror is L2, satisfying the relationship: 1.2*L1≤L2≤5*L1.

[0073] In steps 701 to 703, optionally, the large-aperture spherical equal-thickness optical window, Cassegrain system, compensating mirror and detector assembly to be tested can be installed in a position that meets the above positional constraints using appropriate tooling, and the corresponding tooling can be removed after installation.

[0074] 704. Place the large-aperture spherical equal-thickness optical window detection system at the center in front of the collimator, which is used to emit the detection beam.

[0075] Figure 8 This application provides an illustration of an application scenario for detecting a large-aperture spherical equal-thickness optical window, as shown in the embodiments of this application. Figure 8 As shown, after assembling the large-aperture spherical equal-thickness optical window detection system (including the integration of the load mounting assembly, support assembly, gearbox assembly, and Cassegrain compensation mirror assembly), the entire system is moved in front of the collimator and its position is adjusted to ensure that the optical axis of the large-aperture spherical equal-thickness optical window to be tested is strictly coaxially aligned with the output optical axis of the collimator. Then, using the collimator as a standard light source, a collimated detection beam is emitted. This beam first enters the surface of the optical window under test, then enters the Cassegrain system, passes through the compensation mirror, and is finally received and imaged by the detector assembly.

[0076] 705. By using the reducer assembly mounted on the support assembly, the load mounting assembly is controlled to adjust the pitch angle of the large-aperture spherical equal-thickness optical window to be tested, and to maintain the pitch angle of the large-aperture spherical equal-thickness optical window to be tested.

[0077] Specifically, the operator turns the handle 4-1 in the gearbox assembly, and the handwheel 4-2 connected to the handle 4-1 drives the worm gear to rotate, which in turn drives the worm wheel to output at a lower speed and higher torque, so that the transmission shaft drives the load mounting assembly 1 to adjust the pitch angle of the large-diameter spherical equal-thickness light window to be tested.

[0078] During the pitch angle adjustment process of the large-aperture spherical constant-thickness optical window to be tested, the radius of curvature of the large-aperture spherical constant-thickness optical window to be tested is R, and the vertical rotation range of the pitch angle of the large-aperture spherical constant-thickness optical window to be tested is ≥ Where D1 is the aperture of the large-aperture spherical optical window to be tested, D2 is the aperture of the primary mirror in the Seiglin system, and ≮ indicates not less than.

[0079] 706. At any pitch angle, acquire the light signal detected by the detector assembly, and compare the detected light signal with the ideal imaging result to obtain the imaging performance of the large-aperture spherical equal-thickness optical window under test at any pitch angle.

[0080] In an optional embodiment, the azimuth angle of the large-aperture spherical equal-thickness optical window to be tested can also be adjusted by removing, rotating, and reinstalling it on the load mounting assembly; wherein the range of the azimuth angle is 0° to 360°.

[0081] The azimuth angle refers to the relative rotation angle in the horizontal direction formed by the rotation of the large-aperture spherical equal-thickness optical window to be tested around its own optical axis (i.e., the line connecting the center of the sphere and the center of curvature) on the load mounting assembly. It is expressed as a clockwise or counterclockwise rotation angle relative to the initial mounting position, and ranges from 0° to 360°.

[0082] After adjusting the azimuth angle of the large-aperture spherical equal-thickness optical window to be tested, the optical signal is further re-detected by the detector assembly to determine the imaging performance of the large-aperture spherical equal-thickness optical window under different azimuth angles and different pitch angles.

[0083] In summary, the large-aperture spherical equal-thickness optical window detection system provided in this application, in conjunction with a collimator, enables the detection of the imaging effects of a large-aperture spherical equal-thickness optical window under different pitch and azimuth angles. Combined with the precise adjustment and hand-cranked rotation design of the gearbox assembly, it can achieve full-surface detection scanning of the large-aperture spherical equal-thickness optical window under test, effectively improving the coverage and detection accuracy of large-aperture spherical equal-thickness optical windows, and providing a complete and reliable detection solution for the practical application of large-aperture optical windows.

[0084] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of a necessary general-purpose hardware platform, or by a combination of hardware and software. Finally, it should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0085] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A detection system for a large-aperture spherical equal-thickness optical window, used for detecting the imaging performance of a large-aperture spherical optical window to be tested, wherein the front and rear surfaces of the large-aperture spherical equal-thickness optical window to be tested are concentric spheres, the surface F-number of the large-aperture spherical optical window to be tested is F, and the window diameter is D1, satisfying the following relationships: 0.3≤F≤10, 200mm≤D1≤1000mm, characterized in that... The system includes: A Cassegrain compensation mirror assembly, comprising: a Cassegrain system, a compensation mirror, and a detector assembly; The Cassegrain system includes a primary mirror and a secondary mirror. The primary mirror and the secondary mirror form an image independently. The primary mirror and the secondary mirror are coaxially positioned. The aperture of the primary mirror is D2, and the aperture of the secondary mirror is D3. The obstruction ratio of the primary and secondary mirrors is D3 / D2. The combined focal length of the primary mirror and the secondary mirror is f, satisfying the following relationship: 100mm≤D2≤500mm, 0.1≤D3 / D2≤0.6, 100mm≤f≤1000mm; The compensating mirror includes a first compensating mirror, a second compensating mirror, and a third compensating mirror placed coaxially with the secondary mirror. The first compensating mirror, the second compensating mirror, and the third compensating mirror are arranged sequentially along the optical axis and pass through the central hole of the primary mirror. In the process of detecting the large-aperture spherical equal-thickness optical window to be tested, light rays pass sequentially along the incident direction through the large-aperture spherical equal-thickness optical window to be tested, the primary mirror, the secondary mirror, the first compensation mirror, the second compensation mirror, the third compensation mirror, and the detector assembly. The light signal detected by the detector assembly is used to evaluate the imaging performance of the large-aperture spherical equal-thickness optical window to be tested.

2. The large-aperture spherical equal-thickness optical window detection system as described in claim 1, characterized in that, The distance between the primary mirror and the secondary mirror is L1, the distance between the concave surface of the large-aperture spherical equal-thickness optical window to be tested and the front surface of the primary mirror is L2, and the distance between the front surface of the first compensation mirror and the front surface of the secondary mirror is L3, satisfying the following relationship: 1.2*L1≤L2≤5*L1, 0.2≤L3 / L1≤5.

3. The large-aperture spherical equal-thickness optical window detection system as described in claim 1, characterized in that, The first compensating lens is a meniscus lens with its convex surface facing the secondary lens; the second compensating lens is a biconvex lens; the third compensating lens is a biconcave lens. The front surfaces of the first and second compensating lenses are aspherical, while the rear surfaces of the first, second, and third compensating lenses are spherical.

4. The large-aperture spherical equal-thickness optical window detection system as described in claim 1, characterized in that, The Cassegrain compensation lens assembly shares the same image plane and focal length as the Cassegrain system.

5. The large-aperture spherical equal-thickness optical window detection system as described in claim 1, characterized in that, The detector assembly is a camera with a resolution of ≥1920*1200 and a pixel size of <6μm.

6. The large-aperture spherical equal-thickness optical window detection system as described in claim 1, characterized in that, The system further includes: a load mounting assembly, a support assembly, and a gearbox assembly, wherein the load mounting assembly and the gearbox assembly are fixed to the support assembly; The load mounting component is used to mount the large-aperture spherical equal-thickness optical window to be tested; The support assembly is used to mount the load mounting assembly, the cassette-type compensation mirror assembly, and the gearbox assembly; The gearbox assembly is connected to the load mounting assembly via a drive shaft, and is used to control the load mounting assembly to adjust the pitch angle of the large-aperture spherical equal-thickness optical window to be tested, and to maintain the pitch angle of the large-aperture spherical equal-thickness optical window to be tested.

7. The large-aperture spherical equal-thickness optical window detection system according to claim 6, characterized in that, The load mounting assembly includes: a mounting ring frame, a left pitch support, a right pitch support, a counterweight, and reinforcing ribs; The mounting ring is used to mount the large-aperture spherical equal-thickness optical window to be tested; The left pitch support and the right pitch support are fixedly connected to the left and right sides of the mounting ring frame, respectively. The two ends of the reinforcing rib are connected to the left pitch support and the right pitch support, respectively. The counterweight is fixedly installed on the left pitch support and the right pitch support at the ends away from the mounting ring frame. The counterweight is adjusted according to the weight of the large-diameter spherical equal-thickness optical window to be tested.

8. The large-aperture spherical equal-thickness optical window detection system according to claim 7, characterized in that, The support assembly includes a first bearing assembly, a second bearing assembly, a gearbox bracket, a cartridge bracket, and a handle, all mounted on the base plate. Wherein, the axes of the first bearing assembly and the second bearing assembly are parallel; the left pitch bracket is connected to the inner or outer ring of the first bearing assembly, and the right pitch bracket is connected to the inner or outer ring of the second bearing assembly; the load mounting assembly rotates based on the first bearing assembly and the second bearing assembly, and the center of the concave surface of the large-diameter spherical equal-thickness optical window to be tested is located on the common axis of the first bearing assembly and the second bearing assembly; When the load mounting assembly rotates, it causes the large-aperture spherical equal-thickness optical window under test to rotate around the center of the concave surface of the large-aperture spherical equal-thickness optical window under test. The cartridge component bracket is used to install the cartridge plus compensation lens assembly. The cartridge component bracket is provided with an oblong hole, which is used to enable the cartridge plus compensation lens assembly to move in both horizontal and vertical directions. The horizontal position adjustment is ±10mm, and the vertical position adjustment is ±5mm. The gearbox bracket is used to mount the gearbox assembly.

9. The large-aperture spherical equal-thickness optical window detection system according to claim 8, characterized in that, The distance between the rotation center of the load mounting assembly and the center of the optical window of the large-aperture spherical equal-thickness optical window to be tested is d1, where 100mm≤d1≤1000mm.

10. The large-aperture spherical equal-thickness optical window detection system according to claim 6, characterized in that, The gearbox assembly includes: a handle, a handwheel, and a gearbox; The gearbox assembly uses a worm gear transmission mechanism. The handle is fixedly connected to the handwheel, which is located at the input end of the gearbox. The gearbox is used to convert a high-speed, low-torque input into a low-speed, high-torque output.

11. The large-aperture spherical equal-thickness optical window detection system according to claim 6, characterized in that, During the process of adjusting the pitch angle of the large-aperture spherical equal-thickness optical window to be tested by controlling the load mounting assembly through the gearbox assembly, the radius of curvature of the large-aperture spherical equal-thickness optical window to be tested is R, and the vertical rotation range of the pitch angle of the large-aperture spherical equal-thickness optical window to be tested is ≥ .

12. A method for detecting large-aperture spherical equal-thickness optical windows, applied to the large-aperture spherical equal-thickness optical window detection system described in claims 1 to 11, characterized in that, The method includes: The Cassegrain system is assembled and adjusted so that the primary and secondary mirrors of the Cassegrain system are placed coaxially. The positions of the detector assembly and the compensating mirror are determined based on the position of the Cassegrain system. The compensating mirror includes a first compensating mirror, a second compensating mirror, and a third compensating mirror placed coaxially with the secondary mirror. The distance between the primary and secondary mirrors is L1, and the distance between the front surfaces of the first and secondary mirrors is L3, satisfying the relationship: 0.2 ≤ L3 / L1 ≤ 5. The Cassegrain plus compensating mirror assembly, which includes the Cassegrain system, the compensating mirrors, and the detector assembly, shares the same image plane and focal length with the Cassegrain system. The large-diameter spherical equal-thickness optical window to be tested is installed on the load mounting assembly by means of shaft hole fitting and end face positioning, and the load mounting assembly is fixed to the support assembly; The cassette-type compensation lens assembly is installed on the support assembly; wherein, the distance between the concave surface of the large-aperture spherical equal-thickness optical window to be tested and the front surface of the primary mirror is L2, satisfying the relationship: 1.2*L1≤L2≤5*L1; The large-aperture spherical equal-thickness optical window detection system is placed at the center in front of the collimator, which is used to emit the detection beam. The reducer assembly installed on the support assembly controls the load mounting assembly to adjust the pitch angle of the large-aperture spherical equal-thickness optical window to be tested, and to maintain the pitch angle of the large-aperture spherical equal-thickness optical window to be tested. At any pitch angle, the light signal detected by the detector assembly is acquired, and the detected light signal is compared with the ideal imaging result to obtain the imaging performance of the large-aperture spherical equal-thickness optical window under test at any pitch angle.

13. The method for detecting a large-aperture spherical equal-thickness optical window according to claim 12, characterized in that, The method further includes: The orientation angle of the large-aperture spherical equal-thickness optical window to be tested is adjusted by removing, rotating, and reinstalling it on the load mounting assembly; wherein the orientation angle ranges from 0° to 360°. After adjusting the azimuth angle of the large-aperture spherical equal-thickness optical window to be tested, the optical signal is re-detected by the detector assembly to determine the imaging performance of the large-aperture spherical equal-thickness optical window to be tested under different azimuth angles and different pitch angles.

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