Method for assembling and adjusting a long focal length compact optical system

Abstract

The application relates to a long-focus compact optical system assembling and adjusting method, which comprises the following steps: establishing an assembling and adjusting reference, installing a telescope system and adjusting the image quality of the telescope system; installing an inner focusing autocollimator, making the optical path of the focusing autocollimator and a secondary mirror coaxial, installing a folding mirror assembly and a converging mirror assembly coaxial tooling, and making the output optical path and the return optical path of the focusing autocollimator parallel, preliminary assembling and adjusting the telescope system and the converging system, and assembling and adjusting the optical system. The application reduces the assembling and adjusting difficulty.

Description

Technical Field

[0001] This invention relates to the field of optomechanical assembly and adjustment technology, and specifically to an assembly and adjustment method for a long focal length compact optical system. Background Technology

[0002] Cassette telescope systems, due to their large aperture and long focal length, can collect more information and have become one of the main configurations of optical systems for optoelectronic products. However, due to structural size limitations, the optical system needs to be spatially compressed.

[0003] Adding two plane mirrors between the cassette telescope system and the focusing system to form a rotating optical path can move the focal point of the telescope system forward. However, adding optical components to the optical system will also introduce errors. The wavefront aberration of the optical system requires RMS≤0.09λ, where λ represents the measurement wavelength of the laser interferometer 1. Therefore, it is difficult to achieve system assembly and adjustment after introducing errors.

[0004] Therefore, there is a need to provide a method for assembling and adjusting a compact optical system with a long focal length to solve the above problems. Summary of the Invention

[0005] This invention provides a method for assembling and adjusting a compact optical system with a long focal length. By using a laser interferometer, an internal focusing autocollimator, a standard plane mirror, and a dedicated axial tooling, it is possible to quickly and effectively establish an assembly and adjustment benchmark, streamline the assembly process, ensure that the exit pupil of the telescope system coincides with the exit pupil of the converging system, obtain wavefront aberrations that meet the system requirements, and avoid repeated blind adjustments. This solves the problem in existing technologies where adding optical components to an optical system introduces errors, making it difficult to assemble and adjust the system.

[0006] The assembly and adjustment method of a long focal length compact optical system of the present invention adopts the following technical solution: including:

[0007] A mounting reference is established using the primary mirror and a laser interferometer. The secondary mirror components are then installed based on the mounting reference to form a telescope system. The image quality of the telescope system is adjusted, and the position of the secondary mirror component is locked.

[0008] An internal focusing autocollimator is installed on the back of the secondary mirror of the telescope system, and the focusing autocollimator is connected to the optical path of the secondary mirror in the telescope system.

[0009] Remove the secondary mirror component, install the folding mirror assembly into the telescope system, and perform a series connection between the two folding mirrors of the folding mirror assembly. After installing the converging mirror assembly series connection tooling into the converging mirror tube, install it into the converging system. Adjust the position of the folding mirrors in different modes of the autocollimator to make the output optical path and the return optical path of the autocollimator parallel.

[0010] Remove the converging lens assembly tandem tooling, assemble the converging lens assembly into the converging lens tube, move the secondary mirror component into the system and connect it to the primary mirror component, remove the internal focusing autocollimator, and complete the initial assembly and adjustment of the telescope system and the converging system.

[0011] A standard plane mirror perpendicular to the beam is set at the output end of the converging system. The position of the folding mirror is adjusted according to the coma term of the wave aberration resolution of the optical system until the exit pupil of the telescope system coincides with the entrance pupil of the converging system. The position of the converging system is adjusted according to the defocus term of the wave aberration resolution of the optical system until the wave aberration value of the optical system is minimized, that is, the optical system is assembled and adjusted.

[0012] Preferably, the steps for establishing the assembly and adjustment reference are as follows:

[0013] Align the primary mirror and the laser interferometer;

[0014] Place the standard sphere at the focal point of the primary mirror;

[0015] Simultaneously adjust the orientation and pitch of the primary mirror and the standard sphere until the laser interferometer's output rays are parallel to the optical axis of the primary mirror;

[0016] Furthermore, the laser interferometer measures the surface shape of the primary mirror to obtain the minimum value, thus locking the position of the primary mirror;

[0017] The optical axis formed by the primary mirror and the quasi-laser interferometer is used as the assembly reference for this assembly and adjustment.

[0018] Preferably, the steps for adjusting the image quality of the telescope system are as follows:

[0019] Place the standard sphere at the focal point of the telescope system;

[0020] The positions of the secondary mirror and the standard sphere are moved synchronously in the horizontal and vertical directions until the coma value is minimized in the Zernike resolution of the wave aberration measurement of the telescope system.

[0021] The positions of the secondary mirror and the standard sphere are moved synchronously along the optical axis until the spherical aberration value is minimized in the Zernike resolution of the wave aberration measurement of the telescope system.

[0022] Fix the secondary mirror and secondary mirror bracket of the secondary mirror component.

[0023] At this point, the image quality adjustment of the telescope system is completed.

[0024] Preferably, the step of aligning the optical paths of the focusing autocollimator and the secondary mirror in the secondary mirror assembly is as follows:

[0025] In autocollimation mode, adjust the azimuth and pitch of the internal focusing autocollimator.

[0026] Until the internal focusing autocollimator and the back autocollimator of the secondary lens are aligned;

[0027] In internal focusing autocollimator mode

[0028] Adjust the focal length of the internal focusing autocollimator until the crosshairs on the back of the secondary mirror can be observed through the internal focusing autocollimator.

[0029] Adjust the position of the internal focusing autocollimator in both the horizontal and vertical directions so that the center image of the crosshairs on the back of the collimator is located at the origin of the internal focusing autocollimator.

[0030] This completes the optical path coupling between the focusing autocollimator and the secondary mirror in the secondary mirror component.

[0031] Preferably, the step of adjusting the position of the folding mirror in different modes of the autocollimator to make the output optical path of the autocollimator parallel to the return optical path is as follows:

[0032] Among them, the two folding mirrors are the first folding mirror and the second folding mirror;

[0033] In the autocollimation mode of the internal focusing autocollimator, the positions of the first and second folding mirrors are rotated to autocollimate with the reflecting surface of the converging mirror assembly and the internal focusing autocollimator.

[0034] In the internal focusing autocollimator in internal focusing mode, the position of the second folding mirror is translated in the horizontal and vertical directions so that the center of the crosshair of the converging lens assembly is located at the origin of the internal focusing autocollimator.

[0035] At this point, the output optical path of the autocollimator is parallel to the return optical path.

[0036] Preferably, the steps for installing the internal focusing autocollimator are as follows:

[0037] Align the internal focusing autocollimator with the back of the secondary mirror;

[0038] Adjust the height of the internal focusing autocollimator so that the center of the internal focusing autocollimator is at the same height as the center of the secondary mirror;

[0039] This completes the installation of the internal focusing autocollimator.

[0040] Preferably, the steps for fine-tuning the position of the folding mirror based on the coma term resolved by the wave aberration of the optical system are as follows:

[0041] When the coma term of the wave aberration resolution of the optical system is ≥0.01, the position of the second folding mirror is finely adjusted in the horizontal and vertical directions.

[0042] If the coma term of the wave aberration resolution of the optical system is less than 0.01, then no adjustment of the position of the folding mirror is performed.

[0043] Preferably, the step of adjusting the position of the converging system based on the defocus term in the Zernike resolution value of the wave aberration of the optical system is as follows:

[0044] If the absolute value of the defocus term in the Zernike resolution of the wavelet aberration of the optical system is ≥0.01, shift the position of the converging system along the optical axis until the wavelet aberration of the optical system is minimized.

[0045] If the absolute value of the defocus term in the Zernike resolution of the wavelet aberration of the optical system is ≤0.01, then the wavelet aberration value is at its minimum and no adjustment is required.

[0046] Preferably, after the secondary mirror component is moved into the system, the system further includes:

[0047] Determine whether the back of the secondary mirror is autocollimated with the internal focusing autocollimator, and whether the intersection of the crosshairs on the back of the secondary mirror is located at the origin of the internal focusing autocollimator.

[0048] If both are yes, then the secondary mirror component is connected to the primary mirror component;

[0049] If one of these conditions is not met, disassemble the secondary mirror and its support, and readjust the image quality of the telescope system until the back of the secondary mirror and the internal autocollimator are autocollimated, and the crosshair intersection on the back of the secondary mirror is located at the origin of the internal autocollimator.

[0050] Preferably, the back of the secondary mirror is coated with a reflective film in the visible light band, wherein the crosshairs on the back are not coated.

[0051] The beneficial effects of this invention are:

[0052] Using a laser interferometer and a standard spherical optical system as a reference, the secondary mirror is installed to form a telescope system. A folding mirror assembly is then installed in the telescope system, and a converging mirror assembly coupling fixture is installed in the converging lens tube and then installed in the converging system. An internal focusing autocollimator is used to align the folding mirror assembly, primary mirror, and secondary mirror of the telescope system. The converging mirror assembly coupling fixture is then removed, and the converging mirror assembly is reassembled into the converging lens tube to restore the converging system, thus completing the initial assembly and adjustment of the converging and telescope systems. At this point, a standard plane mirror is placed at the output end of the converging system of the initially assembled system. The wavefront aberration of the system is obtained using a laser interferometer, and the positions of the folding mirror and converging system are adjusted according to the wavefront aberration until the exit pupil of the telescope system coincides with the entrance pupil of the converging system, and the wavefront aberration value of the system is minimized. At this point, the assembly and adjustment of the optical system is complete. The entire process of this invention can quickly and effectively establish the system's assembly and adjustment reference. Then, the optical system is divided into two parts, the telescope system and the convergence system, and is assembled and adjusted in sequence. This streamlines the assembly and adjustment process, thereby ensuring that the exit pupil of the telescope system coincides with the exit pupil of the convergence system, obtaining wavelet aberrations that meet the system requirements, avoiding repeated blind adjustments, and reducing the difficulty of assembly and adjustment. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a schematic diagram of the overall structure of an embodiment of a method for assembling and adjusting a long focal length compact optical system according to the present invention.

[0055] Figure 2 This is a schematic diagram of the secondary mirror structure of a method for assembling and adjusting a long focal length compact optical system according to the present invention.

[0056] Figure 3 This is a schematic diagram illustrating the use of a laser interferometer and a standard sphere for assembly and adjustment reference in this invention;

[0057] Figure 4 This is a schematic diagram of the optical system of the assembly and adjustment method of a long focal length compact optical system according to the present invention.

[0058] Figure 5 This is a schematic diagram of the measurement optical path of an optical system for a method of assembling and adjusting a long focal length compact optical system according to the present invention.

[0059] In the diagram: 1. Laser interferometer; 3. Primary mirror; 4. Secondary mirror; 5. First folding mirror; 6. Second folding mirror; 7. Converging mirror assembly; 8. Converging mirror assembly tandem tooling; 9. Standard sphere; 10. Standard plane mirror. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] The present invention provides a method for assembling and adjusting a compact optical system with a long focal length, such as... Figure 1 As shown, it includes:

[0062] S1. Establish the installation and adjustment benchmark, install the telescope system and adjust the image quality of the telescope system;

[0063] Specifically, a mounting reference is established using the primary mirror 3 and the laser interferometer 1. The secondary mirror component is then installed based on the mounting reference to form a telescope system. The image quality of the telescope system is adjusted, and the position of the secondary mirror 4 of the secondary mirror component is locked.

[0064] The steps for establishing the assembly reference are as follows: Align the primary mirror 3 and the laser interferometer 1, and place the standard sphere 9 at the focal point of the primary mirror 3; Simultaneously adjust the azimuth and pitch of the primary mirror 3 and the standard sphere 9 until the light emitted from the laser interferometer 1 is parallel to the optical axis of the primary mirror; and the laser interferometer 1 measures the surface shape of the primary mirror 3 to obtain the minimum value, and lock the position of the primary mirror 3, that is, take the optical axis formed by the primary mirror 3 and the quasi-laser interferometer 1 as the assembly reference for this assembly.

[0065] The steps for adjusting the image quality of the telescope system are as follows: place the standard sphere 9 at the focal point of the telescope system; move the secondary mirror 4 and the standard sphere 9 simultaneously in the horizontal and vertical directions until the coma value in the Zernike resolution of the wave aberration measurement of the telescope system is minimized; move the secondary mirror 4 and the standard sphere 9 simultaneously along the optical axis until the spherical aberration value in the Zernike resolution of the wave aberration measurement of the telescope system is minimized; at this point, the image quality adjustment of the telescope system is complete.

[0066] S2. Install the internal focusing autocollimator and make the optical path of the focusing autocollimator and the secondary mirror cross-axis.

[0067] Specifically, an internal focusing autocollimator 2 is placed on the back side of the secondary mirror 4 in the telescope system, and the focusing autocollimator 2 is connected to the optical path of the secondary mirror 4 in the telescope system.

[0068] Specifically, the steps to align the optical paths of the focusing autocollimator 2 and the secondary mirror 4 in the secondary mirror assembly are as follows: With the internal focusing autocollimator 2 in autocollimation mode, adjust its azimuth and pitch until the back of the internal focusing autocollimator 2 and the secondary mirror 4 are autocollimated; with the internal focusing autocollimator 2 in internal focusing mode, adjust its focal length until the crosshairs on the back of the secondary mirror 4 can be observed through the internal focusing autocollimator 2; adjust the position of the internal focusing autocollimator 2 in both horizontal and vertical directions so that the center image of the crosshairs on the back of the secondary mirror 4 observed by the internal focusing autocollimator 2 is located at the origin of the internal focusing autocollimator 2; thus, the optical path alignment between the focusing autocollimator 2 and the secondary mirror 4 in the secondary mirror assembly is completed.

[0069] S3. Install the folding mirror assembly and converging mirror group coupling tooling, and make the output optical path of the focusing autocollimator parallel to the return optical path;

[0070] Specifically, the secondary mirror component is removed, the folding mirror assembly is installed into the telescope system, and the two folding mirrors of the folding mirror assembly are coupled together. The converging mirror assembly coupling tool 8 is then installed into the converging mirror tube 7 and then into the converging system. The position of the folding mirror is adjusted in different modes of the autocollimator 2 until the output optical path of the autocollimator 2 is parallel to the return optical path reflected by the converging mirror assembly coupling tool 8.

[0071] The steps for adjusting the position of the folding mirrors in different modes of the focusing autocollimator 2 until the output optical path of the focusing autocollimator 2 is parallel to the return optical path reflected by the converging lens assembly axial fixture 8 are as follows: The two folding mirrors of the two folding mirror assemblies are, in sequence, the first folding mirror 5 and the second folding mirror 6; in the autocollimation mode of the internal focusing autocollimator 2, the positions of the first folding mirror 5 and the second folding mirror 6 are rotated so that the reflecting surface of the converging lens assembly axial fixture 8 and the internal focusing autocollimator 2 are autocollimated; in the internal focusing mode of the internal focusing autocollimator 2, the position of the second folding mirror 6 is translated in the horizontal and vertical directions so that the image center of the crosshair of the converging lens assembly axial fixture 8 is located at the origin of the internal focusing autocollimator 2. At this time, the output optical path of the focusing autocollimator 2 is parallel to the return optical path reflected by the converging lens assembly axial fixture 8.

[0072] In this embodiment, it is considered that when the parallelism between the output optical path and the return optical path of the autocollimator 2 is less than 2″, the output optical path of the autocollimator 2 is considered to be parallel to the return optical path reflected by the converging lens assembly tandem tool 8.

[0073] S4, preliminary assembly and adjustment of the telescope system and the focusing system;

[0074] Specifically, remove the converging lens assembly tandem tool 8, assemble the converging lens assembly into the converging lens tube 7, move the secondary lens component into the system and connect it to the primary lens component, remove the internal focusing autocollimator 2, and complete the initial assembly and adjustment of the telescope system and the converging system.

[0075] The process includes, after moving the secondary mirror component into the system, determining whether the back of the secondary mirror 4 is autocollimated with the internal focusing autocollimator 2, and whether the crosshair intersection point on the back of the secondary mirror is located at the origin of the internal focusing autocollimator 2; if the back of the secondary mirror 4 is autocollimated with the internal focusing autocollimator 2, and the crosshair intersection point on the back of the secondary mirror is located at the origin of the internal focusing autocollimator 2, then the secondary mirror component is connected to the primary mirror component; if the back of the secondary mirror 4 is not autocollimated with the internal focusing autocollimator 2, or the crosshair intersection point on the back of the secondary mirror is not located at the origin of the internal focusing autocollimator 2, then the secondary mirror 4 and the secondary mirror support are disassembled, and the image quality of the telescope system is readjusted until the back of the secondary mirror 4 is autocollimated with the internal focusing autocollimator 2, and the crosshair intersection point on the back of the secondary mirror is located at the origin of the internal focusing autocollimator 2.

[0076] S5. Assembly and adjustment of the optical system;

[0077] Specifically, a standard plane mirror 10 perpendicular to the beam is set at the output end of the converging system, and the position of the folding mirror is adjusted according to the coma term of the wave aberration analysis of the optical system until the exit pupil of the telescope system coincides with the entrance pupil of the converging system; the position of the converging system is adjusted according to the defocus term of the wave aberration analysis of the optical system until the wave aberration value of the optical system is minimized, that is, the final assembly and adjustment of the optical system is completed.

[0078] Specifically, based on the coma term of the Zernike aberration analysis of the optical system, the steps for fine-tuning the position of the folding mirror are as follows: when the coma term of the wave aberration analysis of the optical system is ≥0.01, the position of the second folding mirror 6 is fine-tuned in both the horizontal and vertical directions; when the coma term of the wave aberration analysis of the optical system is <0.01, no adjustment of the position of the folding mirror is performed.

[0079] Specifically, the steps for adjusting the position of the converging system based on the defocus term in the Zernike resolution value of the wavelet aberration of the optical system are as follows: If the absolute value of the defocus term in the Zernike resolution value of the wavelet aberration of the optical system is ≥0.01, shift the position of the converging system along the optical axis until the wavelet aberration value of the optical system is minimized; if the absolute value of the defocus term in the Zernike resolution value of the measurement result is ≤0.01, then the wavelet aberration value meets the requirements and no adjustment is needed.

[0080] Specifically, the back of the secondary mirror 4 is coated with a reflective film in the visible light band. In this embodiment, the visible light band selected is the 632.5nm band. However, the crosshairs on the back are not coated.

[0081] The assembly and adjustment process in this embodiment:

[0082] Before assembly and adjustment: Fabricate converging lens assembly axial tooling 8. The converging lens assembly axial tooling is a reflective crosshair made of glass material, such as... Figure 2 As shown, a 632.5nm band reflective film is coated on the back of the secondary mirror, with a crosshair engraved in the center. The crosshair area is not coated, and the intersection of the crosshairs is located on the optical axis with a coaxiality ≤0.005. It should be noted that after the secondary mirror is properly adjusted, it is fixed to the secondary mirror bracket by adhesive bonding. The secondary mirror bracket and the primary mirror bracket are positioned by matching pins, allowing for repeated disassembly and assembly. During installation, the optical centering is installed into the structural components before being fitted with the converging lens tube to ensure that the intersection of the reticle crosshairs is located on the central axis of the inner wall of the converging lens tube with a coaxiality ≤0.01mm.

[0083] 1) such as Figure 3 As shown, align the primary mirror 3 with the laser interferometer 1 and place the standard sphere 9 at the focal point of the primary mirror 3; simultaneously adjust the azimuth and pitch of the primary mirror 3 and the standard sphere 9 until the emitted light from the laser interferometer 1 is parallel to the optical axis of the primary mirror; and the laser interferometer 1 measures the surface shape of the primary mirror 3 to obtain the minimum value, lock the position of the primary mirror 3 (i.e., fix the primary mirror 3 and the primary mirror bracket by potting glue), and then use the optical axis formed by the primary mirror 3 and the quasi-laser interferometer 1 as the assembly reference for this assembly and adjustment.

[0084] 2) Using the assembly and adjustment reference as a standard, assemble the secondary mirror component on the primary mirror component to form a telescope system. Place the standard sphere 9 at the focal point of the telescope system. By synchronously translating the positions of the secondary mirror 4 and the standard sphere 9 in the horizontal and vertical directions, ensure that the coma value in the Zernike resolution of the wave aberration measurement of the telescope system is minimized (i.e., in this embodiment, if the coma value in the Zernike resolution is ≤0.01, then the coma value is considered to be minimized). Then, synchronously move the positions of the secondary mirror 4 and the standard sphere 9 along the optical axis direction (the direction of the assembly and adjustment reference) until the spherical aberration value in the Zernike resolution of the wave aberration measurement of the telescope system is minimized (i.e., in this embodiment, if the coma value in the Zernike resolution is ≤0.01, then the spherical aberration value is considered to be minimized). At this point, the image quality adjustment of the telescope system is completed. Apply glue to the secondary mirror 4 so that the secondary mirror 4 is connected to the secondary mirror support to obtain the fixed secondary mirror component. After the glue dries, proceed to the next step.

[0085] 3) such as Figure 4 As shown, align the internal focusing autocollimator 2 with the back of the secondary mirror 4 of the secondary mirror assembly, and adjust the height of the internal focusing autocollimator 2 so that the center of the internal focusing autocollimator 2 is at the same height as the center of the secondary mirror 4; set the internal focusing autocollimator 2 to autocollimation mode, and adjust the azimuth and pitch of the internal focusing autocollimator 2 so that the internal focusing autocollimator 2 is autocollimated with the back of the secondary mirror 4; switch the internal focusing autocollimator 2 to internal focusing mode, and adjust the focal length of the internal focusing autocollimator 2 until the crosshairs on the back of the secondary mirror 4 can be observed through the internal focusing autocollimator 2; translate the internal focusing autocollimator 2 horizontally and vertically to ensure that the center of the crosshairs is imaged at the origin of the internal focusing autocollimator 2, with an accuracy better than 2″, i.e., less than or equal to 2″. Keep the position of the internal focusing autocollimator 2 unchanged in subsequent assembly and adjustment steps.

[0086] 4) Remove the secondary mirror components, install the first folding mirror 5 and the second folding mirror 6 into the telescope system, and perform coaxial alignment between the two first folding mirrors 5 and the second folding mirror 6. Switch the internal focusing autocollimator 2 to autocollimation mode, install the converging lens assembly coaxial alignment fixture 8 into the converging lens tube 7, install the converging lens tube 7 into the converging system, and rotate the positions of the first folding mirror 5 and the second folding mirror 6 so that the reflecting surface of the converging lens assembly coaxial alignment fixture 8 is autocollimated with the internal focusing autocollimator 2. Switch the internal focusing autocollimator 2 to internal focusing mode, and in the horizontal direction... The second folding mirror 6 is moved vertically so that the center of the crosshair of the converging lens assembly axial tooling 8 is located at the origin of the internal focusing autocollimator 2 (that is, at this time, the output light path of the focusing autocollimator 2 is reflected by the converging lens assembly axial tooling 8 to form a return light path, and the return light path and the output light path are parallel). It should be noted that in this embodiment, when the parallelism between the output light path and the return light path of the focusing autocollimator 2 is less than 2″, it is considered that the output light path of the focusing autocollimator 2 is parallel to the return light path reflected by the converging lens assembly axial tooling 8.

[0087] 5) such as Figure 5As shown, remove the converging lens assembly coupling tool 8, and assemble the converging lens assembly into the converging lens tube 7 to restore the converging system. Then, move the secondary mirror assembly into the telescope system. Position the secondary mirror support of the secondary mirror assembly and the primary mirror support of the primary mirror assembly using pins. Recheck whether the back of the secondary mirror 4 is autocollimated with the internal focusing autocollimator 2, and whether the intersection of the crosshairs on the back of the secondary mirror 4 is located at the origin of the internal focusing autocollimator 2. If the back of the secondary mirror 4 is autocollimated with the internal focusing autocollimator 2, and the intersection of the crosshairs on the back of the secondary mirror is located at the origin of the internal focusing autocollimator 2, then the secondary mirror assembly is connected to the primary mirror assembly. If the back of the secondary mirror 4 is not autocollimated with the internal focusing autocollimator 2, or if the crosshair intersection on the back of the secondary mirror is not located at the origin of the internal focusing autocollimator 2, then disassemble the secondary mirror 4 and the secondary mirror support, and readjust the image quality of the telescope system until the back of the secondary mirror 4 is autocollimated with the internal focusing autocollimator 2, and the crosshair intersection on the back of the secondary mirror is located at the origin of the internal focusing autocollimator 2. At this point, the initial docking of the telescope system and the converging system is completed, that is, the initial assembly and adjustment of the optical system. At this point, the optical system can form a parallel light path, and the internal focusing autocollimator 2 is moved out of the measurement optical path.

[0088] Place a standard plane mirror 10 at the output of the converging system and adjust its orientation to ensure that the mirror surface of the standard plane mirror 10 is perpendicular to the measurement optical path of the laser interferometer 1. That is, the surface shape of the standard plane mirror 10 measured by the laser interferometer 1 is the optimal surface shape (note that the telescope system should be blocked during measurement to avoid measurement interference). Under the optimal surface shape, the wavefront aberration of the optical system can be measured using the laser interferometer 1 in conjunction with the standard plane mirror 10. When the coma term of the wavefront aberration resolution of the optical system is ≥0.01, the position of the second folding mirror 6 is finely adjusted in the horizontal and vertical directions until the exit pupil of the telescope system coincides with the entrance pupil of the converging system. When the coma term of the wavelet aberration resolution of the optical system is <0.01, it means that the exit pupil of the telescope system coincides with the entrance pupil of the converging system, and no adjustment of the position of the folding mirror is required. If the absolute value of the defocus term (power term) in the Zernike resolution of the wavelet aberration of the optical system is ≥0.01, the position of the converging system is shifted along the optical axis until the wavelet aberration value of the optical system is minimized. If the absolute value of the defocus term (power term) in the Zernike resolution of the measurement result is ≤0.01, it means that the wavelet aberration value is minimized and no adjustment is required, satisfying the wavelet aberration RMS≤0.09λ, where λ represents the measurement wavelength of laser interferometer 1. At this point, the optical path of the system is assembled and adjusted.

[0089] In summary, the assembly and adjustment method for a long focal length compact optical system provided by this invention involves assembling the optical system using a laser interferometer and a standard sphere as an assembly and adjustment reference. Then, using this reference, a secondary mirror is installed to form a telescope system. A folding mirror assembly is installed in the telescope system, and a converging mirror assembly coupling fixture is installed in the converging mirror tube and then installed in the converging system. An internal focusing autocollimator is used to align the folding mirror assembly, primary mirror, and secondary mirror of the telescope system. Then, the converging mirror assembly coupling fixture is removed, and the converging mirror assembly is reassembled into the converging mirror tube to restore the converging system, thus completing the initial assembly and adjustment of the converging and telescope systems. At this point, a standard plane mirror is placed at the output end of the converging system of the initially assembled system. The wavefront aberration of the system is obtained using a laser interferometer, and the positions of the folding mirror and the converging system are adjusted according to the wavefront aberration until the exit pupil of the telescope system coincides with the entrance pupil of the converging system, and the wavefront aberration value of the system is minimized. At this point, the assembly and adjustment of the optical system is complete. The entire process of this invention can quickly and effectively establish the system's assembly and adjustment benchmark. Then, the optical system is divided into two parts, the telescope system and the convergence system, and is assembled and adjusted in sequence. This streamlines the assembly and adjustment process, thereby ensuring that the exit pupil of the telescope system coincides with the exit pupil of the convergence system, obtaining wavelet aberrations that meet the system requirements, avoiding repeated blind adjustments, and reducing the difficulty of assembly and adjustment.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for assembling and adjusting a compact optical system with a long focal length, characterized in that, include: Establish an assembly reference using the primary mirror (3) and the laser interferometer (1), install the secondary mirror component based on the assembly reference to form a telescope system, adjust the image quality of the telescope system, and lock the position of the secondary mirror (4) of the secondary mirror component. An internal focusing autocollimator (2) is installed on the back of the secondary mirror (4) of the telescope system, and the focusing autocollimator (2) is connected to the optical path of the secondary mirror (4) in the telescope system. Remove the secondary mirror component, install the folding mirror assembly into the telescope system, and perform a series connection on the two folding mirrors of the folding mirror assembly. After installing the converging mirror assembly series connection tool (8) into the converging mirror tube (7), install it into the converging system. Adjust the position of the folding mirror in different modes of the autocollimator (2) so that the output optical path of the autocollimator (2) is parallel to the return optical path. Remove the converging lens assembly tandem tooling (8), assemble the converging lens assembly into the converging lens tube (7), move the secondary lens component into the system and connect it to the primary lens component, remove the internal focusing autocollimator (2), and complete the initial assembly and adjustment of the telescope system and the converging system; A standard plane mirror (10) perpendicular to the beam is set at the output end of the converging system, and the position of the folding mirror is adjusted according to the coma term of the wave aberration resolution of the optical system until the exit pupil of the telescope system coincides with the entrance pupil of the converging system. Based on the defocus term of the wavefront aberration resolution of the optical system, adjust the position of the converging system until the wavefront aberration value of the optical system is minimized, which means the optical system assembly and adjustment are complete.

2. The assembly and adjustment method for a long focal length compact optical system according to claim 1, characterized in that, The steps for establishing assembly and adjustment standards are as follows: Align the primary mirror (3) and the laser interferometer (1); Place the standard ball (9) at the focal point of the primary mirror (3); Simultaneously adjust the orientation and pitch of the primary mirror (3) and the standard sphere (9) until the laser interferometer (1) emits light rays that are parallel to the optical axis of the primary mirror; Furthermore, the laser interferometer (1) measures the surface shape of the primary mirror (3) to obtain the minimum value and locks the position of the primary mirror (3); The optical axis formed by the primary mirror (3) and the quasi-laser interferometer (1) is used as the assembly reference for this assembly.

3. The assembly and adjustment method for a long focal length compact optical system according to claim 1, characterized in that, The steps to adjust the image quality of a telescope system are as follows: Place the standard ball (9) at the focal point of the telescope system; The positions of the secondary mirror (4) and the standard sphere (9) are moved synchronously in the horizontal and vertical directions until the coma value is minimized in the Zernike analysis of the wave aberration measurement of the telescope system. The positions of the secondary mirror (4) and the standard sphere (9) are moved synchronously along the optical axis until the spherical aberration value is minimized in the Zernike analysis of the wave aberration measurement of the telescope system. And fix the secondary mirror (4) and the secondary mirror bracket of the secondary mirror component; At this point, the image quality adjustment of the telescope system is completed.

4. The assembly and adjustment method of a long focal length compact optical system according to claim 1, characterized in that, The steps to make the optical paths of the focusing autocollimator (2) and the secondary mirror (4) in the secondary mirror assembly are as follows: In autocollimation mode, adjust the azimuth and pitch of the internal focusing autocollimator (2); Until the back autocollimator (2) and secondary lens (4) are autocollimated; In the internal focusing autocollimator (2) in internal focusing mode Adjust the focal length of the internal focusing autocollimator (2) until the crosshairs on the back of the secondary mirror (4) can be observed through the internal focusing autocollimator (2); Adjust the position of the internal focusing autocollimator (2) in the horizontal and vertical directions so that the center image of the crosshairs on the back of the collimator (4) is observed by the internal focusing autocollimator (2) at the origin of the internal focusing autocollimator (2). This completes the optical path coupling between the focusing autocollimator (2) and the secondary mirror (4) in the secondary mirror component.

5. The assembly and adjustment method for a long focal length compact optical system according to claim 1, characterized in that, The steps for adjusting the position of the folding mirror in different modes of the autocollimator (2) to make the output optical path of the autocollimator (2) parallel to the return optical path are as follows: Among them, the two folding mirrors are the first folding mirror (5) and the second folding mirror (6); In the autocollimation mode of the internal focusing autocollimator (2), the positions of the first folding mirror (5) and the second folding mirror (6) are rotated so that the reflecting surface of the converging lens assembly and the internal focusing autocollimator (2) are autocollimated. In the internal focusing autocollimator (2) in internal focusing mode, the position of the second folding mirror (6) is translated in the horizontal and vertical directions so that the center of the crosshair of the converging lens assembly is located at the origin of the internal focusing autocollimator (2). At this time, the output optical path of the autocollimator (2) is parallel to the return optical path.

6. The assembly and adjustment method of a long focal length compact optical system according to claim 1, characterized in that, The steps for installing the internal focusing autocollimator (2) are as follows: Align the internal focusing autocollimator (2) with the back of the secondary mirror (4); Adjust the height of the internal focusing autocollimator (2) so that the center of the internal focusing autocollimator (2) is at the same height as the center of the secondary mirror (4); That is, the installation of the internal focusing autocollimator (2) is completed.

7. The assembly and adjustment method for a long focal length compact optical system according to claim 5, characterized in that, Based on the coma term resolved by the wave aberration of the optical system, the steps for fine-tuning the position of the folding mirror are as follows: When the coma term of the wave aberration resolution of the optical system is ≥0.01, the position of the second folding mirror (6) is finely adjusted in the horizontal and vertical directions; If the coma term of the wave aberration resolution of the optical system is less than 0.01, then no adjustment of the position of the folding mirror is performed.

8. The assembly and adjustment method of a long focal length compact optical system according to claim 1, characterized in that, The steps for adjusting the position of the converging system based on the defocus term in the Zernike resolution of the wave aberration of the optical system are as follows: If the absolute value of the defocus term in the Zernike resolution of the wavelet aberration of the optical system is ≥0.01, shift the position of the converging system along the optical axis until the wavelet aberration of the optical system is minimized. If the absolute value of the defocus term in the Zernike resolution of the wavelet aberration of the optical system is ≤0.01, then the wavelet aberration value is at its minimum and no adjustment is required.

9. The assembly and adjustment method of a long focal length compact optical system according to claim 1, characterized in that, After the secondary mirror component is moved into the system, the following is also included: Determine whether the back of the secondary mirror (4) is autocollimated with the internal focusing autocollimator (2), and whether the intersection of the cross image on the back of the secondary mirror is located at the origin of the internal focusing autocollimator (2). If both are yes, then the secondary mirror component is connected to the primary mirror component; If one of them is not, disassemble the secondary mirror (4) and the secondary mirror support, and readjust the image quality of the telescope system until the back of the secondary mirror (4) is autocollimated with the internal focusing autocollimator (2), and the cross image intersection point on the back of the secondary mirror is located at the origin of the internal focusing autocollimator (2).

10. The assembly and adjustment method of a long focal length compact optical system according to claim 1, characterized in that, The back of the secondary mirror (4) is coated with a reflective film in the visible light band, wherein the crosshairs on the back are not coated.

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