A method for assembling and adjusting a compact folding-axis multi-reflector optical system

Abstract

This application provides a method for assembling and adjusting a compact folding-axis multi-mirror optical system, relating to the field of precision optomechanical assembly and adjustment technology. This method combines aspherical centering detection and turning processing, transforming the adjustment of aspherical primary and secondary mirrors from traditional adjustment of aspherical optical elements to centering and turning of the outer frame structure, thereby achieving rapid centering and machining and assembly of the aspherical surfaces of the primary and secondary mirrors. In the primary and secondary mirror assembly and adjustment stage, the centering of the mechanical axis and optical axis is guaranteed. Subsequently, the adjustment dimensions of the folding-axis mirror and the three mirrors are effectively separated, reducing the difficulty of subsequent computer-aided assembly and adjustment, ensuring assembly accuracy while significantly improving the assembly and adjustment efficiency of the optical system.

Description

Technical Field

[0001] This invention relates to the field of precision optomechanical assembly and adjustment technology, and in particular provides a method for assembling and adjusting a compact folding-axis multi-reflector optical system. Background Technology

[0002] In recent years, airborne weapon optoelectronic products have been developing towards higher sensitivity, higher resolution, and longer-range detection. To meet the growing demands of combat missions, airborne optical detection systems mostly adopt large-aperture, long-focal-length, high-resolution reflective optical systems. This system has a compact structure, effectively shortening the optical tube length, and is currently the mainstream optical system for long-range detection.

[0003] However, the asymmetry of its system structure and the large number of degrees of freedom in adjustment make the assembly and adjustment of the optical system quite difficult. Each optical component is aspherical and off-axis, and the optical axis undergoes multiple rotations in space, which is completely different from conventional spherical coaxial optical systems. Conventional assembly and adjustment methods such as double-sided centering assembly and machining centering are not applicable. Since this optical system also participates in visible light imaging, and the wavelength of a visible light system is nearly an order of magnitude smaller than that of a mid-wave infrared system, and it has an extremely small field of view and a large aperture, the assembly and adjustment accuracy requirements are very high. Summary of the Invention

[0004] The purpose of this application is to provide a method for assembling and adjusting a compact folding-axis multi-mirror optical system. This method proposes a high-precision centering and turning method for coaxial aspherical mirrors, and proposes angular offset calibration for folding-axis mirrors and off-axis three mirrors. Finally, the system is precisely assembled and adjusted by computer-aided assembly and adjustment, which ensures that the wavefront aberration of the system meets the specifications while improving the assembly and adjustment efficiency.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for assembling and adjusting a compact folding-axis multi-mirror optical system, the compact folding-axis multi-mirror optical system comprising an aspherical primary mirror, an aspherical secondary mirror coaxial with the aspherical primary mirror and forming a primary image point, a folding-axis reflecting mirror located after the primary image point, three off-axis mirrors that refract the beam whose exit direction has been changed by the folding-axis reflecting mirror into a parallel beam, and a stabilizing mirror for final imaging, the method comprising the following steps:

[0007] S1: Using the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer circle and end face of the aspherical primary mirror are finely turned to obtain the aspherical primary mirror.

[0008] S2: Using the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer circle and end face of the outer frame of the aspherical secondary mirror are finely turned to obtain the aspherical secondary mirror.

[0009] S3: Assemble the aspherical primary mirror obtained in S1 and the aspherical secondary mirror obtained in S2 to obtain the primary and secondary mirror components. Use the autocollimating light tube to establish the spatial orthogonal reference position of the folding axis mirror, and adjust the angular deflection of the folding axis mirror until the reference requirements are met.

[0010] S4: The system optical axis, composed of the aspherical primary mirror determined by S1 and the aspherical secondary mirror determined by S2, is established by using an autocollimating light tube to complete the spatial orthogonal reference position, and the angular deviation of the off-axis three mirrors is adjusted until the reference requirements are met;

[0011] S5: Establish a sensitivity matrix model through the offset elements, use a laser interferometer to measure the Zernike coefficient of the entire system, calculate the offset of the optical elements in reverse, finely adjust the translation position of the folding mirror and the off-axis three mirrors, and complete the assembly.

[0012] The compact folding-axis multi-reflector optical system assembly and adjustment method provided by the present invention also has the following feature: S1 includes:

[0013] S1.1: Place the aspherical primary mirror inside the primary mirror frame, insert multiple shims around the aspherical primary mirror for coarse centering, and fix the aspherical primary mirror and the primary mirror frame by injecting adhesive to obtain the initial assembly of the primary mirror with the aspherical primary mirror and the primary mirror frame fixedly connected.

[0014] S1.2: Center the initial assembly of the primary mirror on the rotary machining spindle and secure the rotary machining spindle to the turntable;

[0015] S1.3: Measure the runout of the outer circle and end face of the main mirror frame, and adjust the position and tilt angle of the rotary machining spindle until the runout of the outer circle and end face of the main mirror frame is no more than 0.05mm;

[0016] S1.4: Use a centering instrument to observe the circle drawing amount of the fitted spherical center image of the aspherical primary mirror, observe the runout of the outer ring of the aspherical primary mirror, determine the position of the optical axis of the aspherical primary mirror, and adjust the rotation machining spindle angle and translation amount so that the optical axis of the aspherical primary mirror coincides with the axis of the turntable.

[0017] S1.5: Use a lathe tool to machine the outer circle and end face of the main mirror frame to ensure that the mating axis of the main mirror frame coincides with the optical axis;

[0018] S1.6: Re-inspect the outer frame of the main mirror after S1.5 machining. If it passes the inspection, the machining of the aspherical main mirror is completed.

[0019] The compact folding-axis multi-reflector optical system assembly and adjustment method provided by the present invention also has the following feature: S2 includes:

[0020] S2.1: Place the aspherical secondary mirror inside the secondary mirror frame, insert multiple shims around the aspherical secondary mirror for coarse centering, and fix the aspherical secondary mirror and the secondary mirror frame by injecting adhesive to obtain the initial assembly of the secondary mirror with the aspherical secondary mirror and the secondary mirror frame fixedly connected.

[0021] S2.2: Place the initial assembly of the secondary mirror in the center on the rotary machining spindle, and secure the rotary machining spindle to the turntable.

[0022] S2.3: Measure the runout of the outer circle and end face of the secondary mirror frame, and adjust the position and tilt angle of the rotary machining spindle until the runout of the outer circle and end face of the secondary mirror frame is no more than 0.05mm;

[0023] S2.4: Use a centering instrument to observe the circle drawing of the fitted spherical center image of the secondary mirror, observe the runout of the outer ring of the aspherical secondary mirror, determine the position of the optical axis of the aspherical secondary mirror, and adjust the angle and translation of the rotary machining spindle so that the optical axis of the aspherical secondary mirror coincides with the axis of the turntable.

[0024] S2.5: Use a lathe tool to machine the outer circle and end face of the secondary mirror frame to ensure that the mating axis of the secondary mirror frame coincides with the optical axis;

[0025] S2.6: Re-inspect the secondary mirror frame after S2.5 machining. If it passes the inspection, the machining of the aspherical secondary mirror is completed.

[0026] The compact folding-axis multi-reflector optical system assembly and adjustment method provided by the present invention also has the following feature: S3 includes:

[0027] S3.1: Set up the first photoelectric autocollimating tube, place a pentaprism on the same horizontal plane as the first photoelectric autocollimating tube, and adjust the azimuth and pitch angle of the pentaprism to make it collimated with the first photoelectric autocollimating tube.

[0028] S3.2: Set up a second photoelectric autocollimating tube along the direction of the pentaprism beam output, and adjust the second photoelectric autocollimating tube to collimate it with the pentaprism output beam. The first photoelectric autocollimating tube and the second photoelectric autocollimating tube form a spatial orthogonal rectangular coordinate system.

[0029] S3.3: Assemble the primary and secondary mirror components onto the platform frame, place the platform frame on the multi-dimensional adjustment stage, and adjust the multi-dimensional adjustment stage under the spatial orthogonal rectangular coordinate system obtained in S3.2 so that the back of the secondary mirror in the primary and secondary mirror components is aligned with the first photoelectric autocollimating tube.

[0030] S3.4: Remove the primary and secondary mirror components from the platform frame, install the folding-axis reflector at its theoretical position on the platform frame, and adjust the angular offset position of the folding-axis reflector using the assembly reference established by the first and second photoelectric autocollimating tubes. This ensures that the first and second photoelectric autocollimating tubes are collimated through the folding-axis reflector, thus completing the angular offset adjustment of the folding-axis reflector.

[0031] The compact folding-axis multi-reflector optical system assembly and adjustment method provided by the present invention also has the following feature: S4 includes:

[0032] S4.1: Install the primary and secondary mirror components onto the platform frame and install the off-axis three mirrors;

[0033] S4.2: Detect the optical axis position using the first photoelectric autocollimating light tube;

[0034] S4.3: Observe the reference on the back of the off-axis three mirrors through the second photoelectric autocollimator, adjust the angular deviation of the off-axis three mirrors, and complete the angular deviation adjustment of the off-axis three mirrors.

[0035] The compact folding-axis multi-reflector optical system assembly and adjustment method provided by the present invention also has the following feature: S5 includes:

[0036] S5.1: Autocollimate the standard plane mirror with the large-aperture interferometer;

[0037] S5.2: Position the multi-dimensional adjustment stage in front of the large-aperture interferometer;

[0038] S5.3: Install a stabilizing lens to make the beam exit parallel to the incident light;

[0039] S5.4: A standard plane mirror is set behind the stabilizing mirror to receive the light beam for interference detection;

[0040] S5.5: Adjust the position and angle of the multi-dimensional adjustment stage to align the large-aperture interferometer with the reference on the back of the aspherical secondary mirror;

[0041] S5.6: Determine the 0° field-of-view incident optical axis of the entire optical system and establish a sensitivity matrix model through the offset element;

[0042] S5.7: Use a large-aperture interferometer to measure the Zerni Ke coefficient of the entire optical system and calculate the misalignment of the optical components in reverse.

[0043] S5.8: Finely adjust the translation positions of the folding-axis mirror and the off-axis three mirrors, as well as the angular deflection of the stabilizing mirror, to complete the assembly of the optical system.

[0044] Beneficial effects

[0045] The compact folding-axis multi-reflector optical system assembly and adjustment method provided by this invention combines aspherical centering detection and turning, transforming the adjustment of aspherical primary and secondary mirrors from traditional adjustment of aspherical optical elements to centering and turning of the outer frame structure, thereby realizing rapid centering, turning and assembly of the aspherical primary and secondary mirrors.

[0046] This method ensures the centering of the mechanical axis and optical axis during the primary and secondary mirror assembly and adjustment stage. It effectively separates the adjustment dimensions of the folding mirror and the three mirrors, reducing the difficulty of subsequent computer-aided assembly and adjustment. While ensuring assembly accuracy, it can significantly improve the assembly and adjustment efficiency of the optical system. Attached Figure Description

[0047] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of the optical path of the compact folding-axis multi-reflector system mentioned in this invention;

[0049] Figure 2 A schematic diagram of the centering turning process for an aspherical primary mirror;

[0050] Figure 3 This is a schematic diagram of the centering turning process for an aspherical secondary mirror.

[0051] Figure 4 Establish a schematic diagram for the adjustment benchmark of the folding mirror and the three mirrors;

[0052] Figure 5 Schematic diagram of optical axis collimation principle for primary and secondary mirror components;

[0053] Figure 6 This is a schematic diagram illustrating the principle of angular offset adjustment for a folding-axis reflector.

[0054] Figure 7 This is a schematic diagram illustrating the principle of three-mirror angle offset adjustment.

[0055] Figure 8 This is a schematic diagram of the system assembly and adjustment principle based on interferometric detection.

[0056] Among them, 1: Aspherical primary mirror; 2: Aspherical secondary mirror; 3: Folded-axis reflector; 4: Off-axis three mirrors; 5: Precision stabilizing mirror; 6: Primary mirror outer frame; 7: Rotary machining spindle; 8: Chromatic aberration displacement sensor; 9: Centering instrument; 10: Lathe tool; 11: Secondary mirror outer frame; 12: First photoelectric autocollimating light tube; 13: Pentagonal prism; 14: Secondary photoelectric autocollimating light tube; 15: Platform frame; 16: Multidimensional adjustment stage; 17: Large-aperture interferometer; 18: Standard plane mirror. Detailed Implementation

[0057] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be noted that these embodiments are not intended to limit the present application. Equivalent transformations or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the protection scope of the present application.

[0058] In the description of the embodiments of this application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the creation of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the creation of this application.

[0059] Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0060] The terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0061] A compact folding-axis multi-reflector optical system includes an aspherical primary mirror 1, an aspherical secondary mirror 2 that coaxially follows the optical path with the aspherical primary mirror 1 and forms a primary image point, a folding-axis reflector 3 located after the primary image point, an off-axis triple mirror 4 that refracts the beam whose exit direction has been changed by the folding-axis reflector 3 into a parallel beam, and a stabilizing mirror 5 for final imaging. A schematic diagram of the optical path is shown below. Figure 1As shown, the aspherical primary mirror 1 and the aspherical secondary mirror 2 are coaxial and form a primary image point. The folding-axis mirror 3 is located after the primary image point. After passing through the folding-axis mirror 3, the beam changes its exit direction, is folded to the off-axis three-mirror 4, corrects aberrations, and becomes a parallel beam. The beam finally forms an image on the image plane after reaching the stabilizing mirror 5. This system narrows the incident beam, providing a parallel optical path for subsequent imaging components, which can effectively reduce the aperture size of subsequent optical elements. Its pre-Cassius system can make the aperture larger, and the aberrations of the Cassius system are compensated by the subsequent off-axis three-mirror 4, forming a large-aperture, high-magnification telescope optical system. To reduce the difficulty of assembly and adjustment, the normal of the folding-axis mirror 3 is designed to be at a 45° angle with the optical axis, and the actual optical axis of the off-axis three-mirror 4 is designed to be orthogonal to the optical axes of the primary and secondary mirrors. The system optimizes the optical power allocation of the aspherical primary mirror 1, the aspherical secondary mirror 2, and the off-axis three-mirror 4, so that the system aberrations are effectively controlled. Meanwhile, the system makes full use of space in both the axial and transverse directions, greatly shortening the optical tube length and resulting in a more compact spatial configuration. The aforementioned optical system possesses numerous advantages, including a compact structure, wide spectral range, large aperture and long focal length, and image quality approaching or reaching the diffraction limit.

[0062] like Figure 2-8 As shown in the figure, this application provides a method for assembling and adjusting a compact folding-axis multi-reflector optical system, the method comprising the following steps:

[0063] S1: Using the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer circle and end face of the outer frame of the aspherical primary mirror 1 are finely turned to obtain the calibrated aspherical primary mirror 1.

[0064] S2: Using the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer circle and end face of the outer frame of the aspherical secondary mirror 2 are finely turned to obtain the calibrated aspherical secondary mirror 2.

[0065] S3: Assemble the aspherical primary mirror 1 obtained in S1 and the aspherical secondary mirror 2 obtained in S2 to obtain the primary and secondary mirror components. Establish the spatial orthogonal reference position of the folding-axis mirror 3 with the help of the autocollimating light tube, and adjust the angular deflection of the folding-axis mirror 3 until the reference requirements are met.

[0066] S4: The system optical axis, composed of the aspherical primary mirror 1 determined by S1 and the aspherical secondary mirror 2 determined by S2, is established by using an autocollimating light tube to complete the spatial orthogonal reference position, and the angular deviation of the off-axis three mirrors 4 is adjusted until the reference requirements are met.

[0067] S5: Establish a sensitivity matrix model through the offset element, use a laser interferometer to measure the Zernike coefficient of the entire system, calculate the offset of the optical element in reverse, finely adjust the translation position of the folding mirror 3 and the off-axis three mirrors 4, and complete the assembly.

[0068] The assembly and adjustment method provided in the above embodiments combines aspherical centering detection and turning, transforming the adjustment of the aspherical primary and secondary mirrors from traditional adjustment of aspherical optical elements to centering and turning the outer frame structure, thereby achieving rapid centering, turning, and assembly of the aspherical primary and secondary mirrors. The angular deviation of the folding-axis mirror and the off-axis three mirrors is adjusted by a photoelectric autocollimator, reducing the adjustment degrees of freedom of the two optical components and controlling the system's assembly and adjustment error within the linear range of the computer-aided assembly and adjustment sensitivity matrix. A laser interferometer and a standard plane mirror are used to complete the precise adjustment of the folding-axis mirror and the off-axis three mirrors. This invention achieves centering assurance of the mechanical axis and optical axis during the primary and secondary mirror assembly and adjustment stage, effectively separating the adjustment dimensions of the folding-axis mirror and the three mirrors, reducing the difficulty of subsequent computer-aided assembly and adjustment, ensuring assembly accuracy while significantly improving the assembly and adjustment efficiency of the optical system.

[0069] In some embodiments, such as Figure 2 As shown, S1 includes:

[0070] S1.1: Place the aspherical primary mirror 1 inside the primary mirror outer frame 6, insert multiple shims around the aspherical primary mirror 1 for coarse centering, and fix the aspherical primary mirror 1 and the primary mirror outer frame 6 by injecting adhesive to obtain the initial assembly of the primary mirror with the aspherical primary mirror 1 and the primary mirror outer frame 6 fixedly connected.

[0071] S1.2: Place the initial assembly of the primary mirror in the center on the rotary machining spindle 7, and secure the rotary machining spindle 7 to the turntable;

[0072] S1.3: Measure the runout of the outer circle a surface and the end face b surface of the main mirror outer frame 6, and adjust the position and tilt angle of the rotary machining spindle 7 until the runout of the outer circle a surface and the end face b surface of the main mirror outer frame 6 is no more than 0.05mm;

[0073] S1.4: The centering instrument 9 is used to observe the circle drawing amount of the fitted spherical center image of the aspherical primary mirror 1, and the color difference displacement sensor 8 is used to observe the runout of the outer ring of the aspherical primary mirror 1. The position of the optical axis of the aspherical primary mirror 1 is determined, and the rotation machining spindle angle and translation amount are adjusted so that the optical axis of the aspherical primary mirror 1 coincides with the axis of the turntable.

[0074] S1.5: Use a lathe tool to machine the outer circle a surface and the end face b surface of the main mirror outer frame 6 to ensure that the mating axis of the main mirror outer frame 6 coincides with the optical axis.

[0075] S1.6: Re-inspect the outer frame 6 of the main mirror after S1.5. If it is qualified, the machining of the aspherical main mirror 1 is completed.

[0076] In some embodiments, such as Figure 3 As shown, S2 includes:

[0077] S2.1: Place the aspherical secondary mirror 2 inside the secondary mirror outer frame 11, insert multiple shims around the aspherical secondary mirror 2 for coarse centering, and fix the aspherical secondary mirror 2 and the secondary mirror outer frame 11 by injecting adhesive to obtain the initial assembly of the secondary mirror with the aspherical secondary mirror 2 and the secondary mirror outer frame 11 fixedly connected.

[0078] S2.2: Place the initial assembly of the secondary mirror in the center on the rotary machining spindle 7, and secure the rotary machining spindle 7 to the turntable.

[0079] S2.3: Measure the runout of the outer circle a surface and the end face b surface of the secondary mirror outer frame 11, and adjust the position and tilt angle of the rotary machining spindle 7 until the runout of the outer circle a surface and the end face b surface of the secondary mirror outer frame 11 is no more than 0.05mm;

[0080] S2.4: The centering instrument 9 is used to observe the circle drawing amount of the fitted spherical center image of the secondary mirror, and the color difference displacement sensor 8 is used to observe the runout of the outer ring of the aspherical secondary mirror 2. The position of the optical axis of the aspherical secondary mirror 2 is determined, and the angle and translation amount of the rotary machining spindle 7 are adjusted so that the optical axis of the aspherical secondary mirror 2 coincides with the axis of the turntable.

[0081] S2.5: Use a lathe tool to machine the outer circle a surface and the end face b surface of the secondary mirror outer frame 11 to ensure that the docking axis of the secondary mirror outer frame 11 coincides with the optical axis;

[0082] S2.6: Re-inspect the secondary mirror outer frame 11 after S2.5 machining. If it passes the inspection, the machining of the aspherical secondary mirror 2 is completed.

[0083] In some embodiments, S3 includes:

[0084] S3.1: Set up the first photoelectric autocollimating tube 12, place a pentaprism 13 on the same horizontal plane as the first photoelectric autocollimating tube 12, and adjust the azimuth and pitch angle of the pentaprism 13 so that it is collimated with the first photoelectric autocollimating tube 12.

[0085] S3.2: Set up a second photoelectric autocollimating tube 14 along the beam output direction of the pentaprism 13, and adjust the second photoelectric autocollimating tube 14 to collimate it with the beam output from the pentaprism 13. The first photoelectric autocollimating tube 12 and the second photoelectric autocollimating tube 14 form a spatial orthogonal rectangular coordinate system.

[0086] S3.3: Assemble the primary and secondary mirror components onto the platform frame 15, place the platform frame 15 on the multi-dimensional adjustment stage 16, and adjust the multi-dimensional adjustment stage 16 under the spatial orthogonal rectangular coordinate system obtained in S3.2 so that the back of the secondary mirror in the primary and secondary mirror components is collimated with the first photoelectric autocollimating tube 12.

[0087] S3.4: Remove the primary and secondary mirror components from the platform frame 15, install the folding-axis reflector 3 at the theoretical position on the platform frame 15, and adjust the angular offset position of the folding-axis reflector 3 using the assembly reference established by the first photoelectric autocollimator 12 and the second photoelectric autocollimator 14, so that the first photoelectric autocollimator 12 and the second photoelectric autocollimator 14 are collimated through the folding-axis reflector 3, thus completing the angular offset adjustment of the folding-axis reflector 3.

[0088] In some embodiments, S4 includes:

[0089] S4.1: Install the primary and secondary mirror components onto the platform frame 15, and install the off-axis three mirrors 4;

[0090] S4.2: The optical axis position is detected by the first photoelectric autocollimating light tube 12;

[0091] S4.3: Observe the back reference of the off-axis three-mirror 4 through the second photoelectric autocollimator 14, adjust the angular deviation of the off-axis three-mirror 4, and complete the angular deviation adjustment of the off-axis three-mirror 4.

[0092] In some embodiments, S5 includes:

[0093] S5.1: Autocollimate the standard plane mirror 18 with the large-aperture interferometer 17;

[0094] S5.2: Adjust the multidimensional adjustment stage 16 to be in front of the large-aperture interferometer 17;

[0095] S5.3: Install the stabilizing mirror 5 to make the beam exit parallel to the incident light;

[0096] S5.4: A standard plane mirror 18 is set behind the stabilizing mirror 5 to receive the light beam for interference detection;

[0097] S5.5: Adjust the position and angle of the multi-dimensional adjustment stage 16 to make the large-aperture interferometer 17 aligned with the back reference of the aspherical secondary mirror 2;

[0098] S5.6: Determine the 0° field-of-view incident optical axis of the entire optical system and establish a sensitivity matrix model through the offset element;

[0099] S5.7: Use a large-aperture interferometer 17 to measure the Zerni Ke coefficient of the entire optical system and calculate the misalignment of the optical components in reverse.

[0100] S5.8: Finely adjust the translation positions of the folding-axis mirror 3 and the off-axis three mirrors 4, as well as the angular deflection of the stabilizing mirror, to complete the assembly of the optical system.

[0101] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above description is merely a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A method for assembling and adjusting a compact folding-axis multi-mirror optical system, the compact folding-axis multi-mirror optical system comprising an aspherical primary mirror, an aspherical secondary mirror coaxial with the aspherical primary mirror and forming a primary image point, a folding-axis reflecting mirror located after the primary image point, three off-axis mirrors that refract the beam whose outgoing direction has been changed by the folding-axis reflecting mirror into a parallel beam, and a stabilizing mirror for final imaging, characterized in that, The method includes the following steps: S1: Using the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer circle and end face of the aspherical primary mirror are finely turned to obtain the aspherical primary mirror. S2: Using the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer circle and end face of the outer frame of the aspherical secondary mirror are finely turned to obtain the aspherical secondary mirror. S3: Assemble the aspherical primary mirror obtained in S1 and the aspherical secondary mirror obtained in S2 to obtain the primary and secondary mirror components. Use the autocollimating light tube to establish the spatial orthogonal reference position of the folding axis mirror, and adjust the angular deflection of the folding axis mirror until the reference requirements are met. S4: The system optical axis, composed of the aspherical primary mirror determined by S1 and the aspherical secondary mirror determined by S2, is established by using an autocollimating light tube to complete the spatial orthogonal reference position, and the angular deviation of the off-axis three mirrors is adjusted until the reference requirements are met; S5: Establish a sensitivity matrix model through the offset elements, use a laser interferometer to measure the Zernike coefficient of the entire system, calculate the offset of the optical elements in reverse, finely adjust the translation position of the folding mirror and the off-axis three mirrors, and complete the assembly.

2. The method for assembling and adjusting a compact folding-axis multi-reflector optical system according to claim 1, characterized in that, S1 includes: S1.1: Place the aspherical primary mirror inside the primary mirror frame, insert multiple shims around the aspherical primary mirror for coarse centering, and fix the aspherical primary mirror and the primary mirror frame by injecting adhesive to obtain the initial assembly of the primary mirror with the aspherical primary mirror and the primary mirror frame fixedly connected. S1.2: Center the initial assembly of the primary mirror on the rotary machining spindle and secure the rotary machining spindle to the turntable; S1.3: Measure the runout of the outer circle and end face of the main mirror frame, and adjust the position and tilt angle of the rotary machining spindle until the runout of the outer circle and end face of the main mirror frame is no more than 0.05mm; S1.4: Use a centering instrument to observe the circle drawing amount of the fitted spherical center image of the aspherical primary mirror, observe the runout of the outer ring of the aspherical primary mirror, determine the position of the optical axis of the aspherical primary mirror, and adjust the rotation machining spindle angle and translation amount so that the optical axis of the aspherical primary mirror coincides with the axis of the turntable. S1.5: Use a lathe tool to machine the outer circle and end face of the main mirror frame to ensure that the mating axis of the main mirror frame coincides with the optical axis; S1.6: Re-inspect the outer frame of the main mirror after S1.5 machining. If it passes the inspection, the machining of the aspherical main mirror is completed.

3. The method for assembling and adjusting a compact folding-axis multi-reflector optical system according to claim 1, characterized in that, S2 includes: S2.1: Place the aspherical secondary mirror inside the secondary mirror frame, insert multiple shims around the aspherical secondary mirror for coarse centering, and fix the aspherical secondary mirror and the secondary mirror frame by injecting adhesive to obtain the initial assembly of the secondary mirror with the aspherical secondary mirror and the secondary mirror frame fixedly connected. S2.2: Place the initial assembly of the secondary mirror in the center on the rotary machining spindle, and secure the rotary machining spindle to the turntable. S2.3: Measure the runout of the outer circle and end face of the secondary mirror frame, and adjust the position and tilt angle of the rotary machining spindle until the runout of the outer circle and end face of the secondary mirror frame is no more than 0.05mm; S2.4: Use a centering instrument to observe the circle drawing of the fitted spherical center image of the secondary mirror, observe the runout of the outer ring of the aspherical secondary mirror, determine the position of the optical axis of the aspherical secondary mirror, and adjust the angle and translation of the rotary machining spindle so that the optical axis of the aspherical secondary mirror coincides with the axis of the turntable. S2.5: Use a lathe tool to machine the outer circle and end face of the secondary mirror frame to ensure that the mating axis of the secondary mirror frame coincides with the optical axis; S2.6: Re-inspect the secondary mirror frame after S2.5 machining. If it passes the inspection, the machining of the aspherical secondary mirror is completed.

4. The method for assembling and adjusting a compact folding-axis multi-reflector optical system according to claim 1, characterized in that, S3 includes: S3.1: Set up the first photoelectric autocollimating tube, place a pentaprism on the same horizontal plane as the first photoelectric autocollimating tube, and adjust the azimuth and pitch angle of the pentaprism to make it collimated with the first photoelectric autocollimating tube. S3.2: Set up a second photoelectric autocollimating tube along the direction of the pentaprism beam output, and adjust the second photoelectric autocollimating tube to collimate it with the pentaprism output beam. The first photoelectric autocollimating tube and the second photoelectric autocollimating tube form a spatial orthogonal rectangular coordinate system. S3.3: Assemble the primary and secondary mirror components onto the platform frame, place the platform frame on the multi-dimensional adjustment stage, and adjust the multi-dimensional adjustment stage under the spatial orthogonal rectangular coordinate system obtained in S3.2 so that the back of the secondary mirror in the primary and secondary mirror components is aligned with the first photoelectric autocollimating tube. S3.4: Remove the primary and secondary mirror components from the platform frame, install the folding-axis reflector at its theoretical position on the platform frame, and adjust the angular offset position of the folding-axis reflector using the assembly reference established by the first and second photoelectric autocollimating tubes. This ensures that the first and second photoelectric autocollimating tubes are collimated through the folding-axis reflector, thus completing the angular offset adjustment of the folding-axis reflector.

5. The method for assembling and adjusting a compact folding-axis multi-reflector optical system according to claim 1, characterized in that, S4 includes: S4.1: Install the primary and secondary mirror components onto the platform frame and install the off-axis three mirrors; S4.2: Detect the optical axis position using the first photoelectric autocollimating light tube; S4.3: Observe the reference on the back of the off-axis three mirrors through the second photoelectric autocollimator, adjust the angular deviation of the off-axis three mirrors, and complete the angular deviation adjustment of the off-axis three mirrors.

6. The method for assembling and adjusting a compact folding-axis multi-reflector optical system according to claim 1, characterized in that, S5 includes: S5.1: Autocollimate the standard plane mirror with the large-aperture interferometer; S5.2: Position the multi-dimensional adjustment stage in front of the large-aperture interferometer; S5.3: Install a stabilizing lens to make the beam exit parallel to the incident light; S5.4: A standard plane mirror is set behind the stabilizing mirror to receive the light beam for interference detection; S5.5: Adjust the position and angle of the multi-dimensional adjustment stage to align the large-aperture interferometer with the reference on the back of the aspherical secondary mirror; S5.6: Determine the 0° field-of-view incident optical axis of the entire optical system and establish a sensitivity matrix model through the offset element; S5.7: Use a large-aperture interferometer to measure the Zernike coefficient of the entire optical system and calculate the misalignment of the optical components in reverse. S5.8: Finely adjust the translation positions of the folding-axis mirror and the off-axis three mirrors, as well as the angular deflection of the stabilizing mirror, to complete the assembly of the optical system.

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