Compact folding-axis multi-mirror optical system assembling and adjusting method

Abstract

The invention provides a compact type folding-axis multi-mirror optical system assembling and adjusting method, and relates to the technical field of precise optical machine assembling and adjusting, the method combines aspheric centering detection and turning functions, aspheric primary and secondary mirror adjustment is changed from traditional adjustment of aspheric optical elements into centering turning of outer frame structural members, and the adjustment precision is improved. In the assembling and adjusting stage of the primary mirror and the secondary mirror, the centering guarantee of a mechanical axis and an optical axis is achieved, the adjusting dimensions of a folding-axis mirror and a third mirror are effectively separated subsequently, the difficulty of subsequent computer-assisted assembling and adjusting is lowered, the assembling precision is guaranteed, and meanwhile the assembling and adjusting efficiency of an optical system is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of precision optical-mechanical assembly and adjustment, and in particular provides an assembly and adjustment method for a compact folded-axis multi-reflection optical system. Background Art

[0002] In recent years, optoelectronic products for airborne weapons are developing towards high sensitivity, high resolution, and long-distance detection. To meet the growing needs of combat missions, airborne optical detection systems mostly use large-caliber, long-focal-length, high-resolution reflective optical systems. This system has a compact structure and can effectively shorten the length of the optical tube, making it the mainstream optical system for long-distance detection.

[0003] However, the asymmetry of the system structure and the large number of degrees of freedom of adjustment make the optical system difficult to assemble and adjust. Each optical component is aspherical and off-axis, and the optical axis is folded multiple times in space, which is completely different from the conventional spherical coaxial optical system. Conventional assembly and adjustment methods such as double-sided centering assembly and turning centering are not applicable. Since the optical system also involves visible light imaging, the visible light system is nearly an order of magnitude smaller than the medium-wave infrared system, and has an ultra-small field of view and a large aperture, so the assembly and adjustment accuracy requirements are relatively high. Summary of the invention

[0004] The purpose of the present application is to provide a compact folded-axis multi-reflector optical system assembly and adjustment method, which proposes a high-precision centering turning method for coaxial aspheric mirrors, and also proposes angle deviation calibration of folded-axis reflectors and off-axis three mirrors. Finally, the precise assembly and adjustment of the system is completed through computer-aided assembly and adjustment base, ensuring that the system wave aberration meets the indicators while improving the assembly and adjustment efficiency.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A compact folding axis multi-reflector optical system assembly and adjustment method, the compact folding axis multi-reflector optical system comprises an aspheric primary mirror, an aspheric secondary mirror coaxial with the aspheric primary mirror and forming a primary image point, a folding axis reflector located after the primary image point, an off-axis three-mirror that folds a light beam whose exit direction is changed by the folding axis reflector into a parallel light beam, and a precision stabilizing mirror for final imaging, the method comprising the following steps:

[0007] S1: With the help of the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer frame docking outer circle and end surface of the aspheric primary mirror are finely turned to obtain the aspheric primary mirror;

[0008] S2: With the help of the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer frame docking outer circle and end surface of the aspheric secondary mirror are finely turned to obtain the aspheric secondary mirror;

[0009] S3: Assemble the aspheric primary mirror obtained in S1 and the aspheric secondary mirror obtained in S2 to obtain the primary and secondary mirror components, complete the establishment of the spatial orthogonal reference position of the folding axis reflector with the help of the self-collimating light tube, and adjust the angular deviation of the folding axis reflector until the reference requirements are met;

[0010] S4: The system optical axis composed of the aspheric primary mirror determined by S1 and the aspheric secondary mirror determined by S2 is used to establish the spatial orthogonal reference position with the help of a self-collimating light pipe, 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 misalignment element, use laser interferometer to measure the Zernike coefficient of the whole system, reversely calculate the misalignment of the optical element, finely adjust the translation position of the folding axis reflector and the off-axis three mirrors, and complete the assembly.

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

[0013] S1.1: Place the aspheric primary mirror in the primary mirror frame, insert a plurality of gaskets around the aspheric primary mirror for rough centering, and solidify and connect the aspheric primary mirror and the primary mirror frame by pouring adhesive to obtain an initial primary mirror assembly in which the aspheric primary mirror and the primary mirror frame are fixedly connected;

[0014] S1.2: Place the primary mirror initial assembly in the center on the rotary processing spindle, and connect the rotary processing spindle to the turntable tightly;

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

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

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

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

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

[0020] S2.1: placing the aspheric secondary mirror in the secondary mirror outer frame, inserting a plurality of gaskets around the aspheric secondary mirror for rough centering, and curing and connecting the aspheric secondary mirror and the secondary mirror outer frame by pouring adhesive to obtain an initial secondary mirror assembly in which the aspheric secondary mirror and the secondary mirror outer frame are fixedly connected;

[0021] S2.2: Place the secondary mirror initial assembly in the center on the rotary processing spindle, and connect the rotary processing spindle to the turntable tightly;

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

[0023] S2.4: Use a centering instrument to observe the amount of the secondary mirror fitting spherical center image drawing circle, observe the amount of runout of the outer ring of the aspherical secondary mirror, determine the position of the optical axis of the aspherical secondary mirror, 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 turning tool to turn the outer circle and end face of the secondary mirror frame to ensure that the docking axis of the secondary mirror frame coincides with the optical axis;

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

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

[0027] S3.1: Set up a first photoelectric autocollimation light tube, place a pentaprism on the same horizontal plane as the first photoelectric autocollimation light tube, and adjust the azimuth and elevation angles of the pentaprism to align it with the first photoelectric autocollimation light tube;

[0028] S3.2: Set up a second photoelectric autocollimation light tube along the direction of the pentaprism light beam, adjust the second photoelectric autocollimation light tube to align it with the pentaprism light beam, and the first photoelectric autocollimation light tube and the second photoelectric autocollimation light 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 table, and adjust the multi-dimensional adjustment table in the spatial orthogonal rectangular coordinate system obtained in S3.2 to align the back surface of the secondary mirror in the primary and secondary mirror components with the first photoelectric self-collimation light tube;

[0030] S3.4: Remove the primary and secondary mirror components from the platform frame, install the folding axis reflector at the theoretical position of the platform frame, and adjust the angular deviation position of the folding axis reflector through the adjustment reference established by the first photoelectric autocollimation light tube and the second photoelectric autocollimation light tube, so that the first photoelectric autocollimation light tube and the second photoelectric autocollimation light tube complete the alignment through the folding axis reflector, thereby completing the angular deviation adjustment of the folding axis reflector.

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

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

[0033] S4.2: Detecting the optical axis position by a first photoelectric self-collimating light tube;

[0034] S4.3: Observe the back reference of the off-axis three mirrors through the second photoelectric self-collimation light tube, 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-reflection optical system assembly and adjustment method provided by the present invention also has the following characteristics: S5 comprises:

[0036] S5.1: Self-align a standard plane mirror with a large aperture interferometer;

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

[0038] S5.3: Install the precision stabilization mirror so that the light beam is parallel to the incident light;

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

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

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

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

[0043] S5.8: Finely adjust the translational position of the folding mirror and the off-axis three mirrors and the angular deviation of the precision stabilization mirror to complete the assembly of the optical system.

[0044] Beneficial Effects

[0045] The compact folded-axis multi-reflector optical system assembly and adjustment method provided by the present invention combines the functions of aspheric centering detection and turning processing, and transforms the adjustment of aspheric primary and secondary mirrors from traditional adjustment of aspheric optical elements to centering and turning outer frame structural parts, thereby realizing rapid centering turning and assembly of the aspheric surfaces of the primary and secondary mirrors.

[0046] This method ensures the centering of the mechanical axis and the optical axis during the primary and secondary mirror adjustment stage, and subsequently effectively separates the adjustment dimensions of the folding mirror and the three mirrors, reducing the difficulty of subsequent computer-aided adjustment. While ensuring assembly accuracy, it can greatly improve the efficiency of optical system adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 A schematic diagram of the optical path of the compact folded-axis multi-reflector system mentioned in the present invention;

[0049] Figure 2 This is a schematic diagram of the centering turning process of the aspheric primary mirror;

[0050] Figure 3 This is a schematic diagram of the centering turning process of the aspheric secondary mirror;

[0051] Figure 4 Establish schematic diagram for folding axis mirror and three-mirror calibration benchmark;

[0052] Figure 5 This is the principle diagram of optical axis alignment of primary and secondary mirror components;

[0053] Figure 6 This is the principle diagram of the angular deviation adjustment of the folded-axis reflector;

[0054] Figure 7 This is the schematic diagram of the three-mirror angular deviation adjustment principle;

[0055] Figure 8 This is the schematic diagram of the system assembly based on interference detection.

[0056] Among them, 1: aspheric primary mirror; 2: aspheric secondary mirror; 3: folded axis reflector; 4: off-axis three mirrors; 5: precision stabilization mirror; 6: primary mirror frame; 7: rotary processing spindle; 8: chromatic aberration displacement sensor; 9: centering device; 10: turning tool; 11: secondary mirror frame; 12: first photoelectric autocollimation light tube; 13: pentaprism; 14: second photoelectric autocollimation light tube; 15: platform frame; 16: multi-dimensional adjustment table; 17: large-aperture interferometer; 18: standard plane mirror. DETAILED DESCRIPTION

[0057] The present application is further described in detail below in conjunction with the accompanying drawings and examples, but it should be noted that these implementation methods are not limitations of the present application, and equivalent changes or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these implementation methods are all within the scope of protection of the present application.

[0058] In the description of the embodiments of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the creation of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the creation of the present application.

[0059] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0060] The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention of this application can be understood by specific circumstances.

[0061] A compact folding axis multi-reflection optical system includes an aspheric primary mirror 1, an aspheric secondary mirror 2 that is coaxial with the aspheric 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 folds the light beam that has changed its exit direction through the folding axis reflector 3 into a parallel light beam, and a precision stabilizing mirror 5 for final imaging. The optical path diagram is shown in FIG. Figure 1As shown, the aspheric primary mirror 1 and the aspheric secondary mirror 2 are in a coaxial optical path and form a primary image point. The folding axis reflector 3 is located after the primary image point. After the light beam passes through the folding axis reflector 3, the aberration is corrected and becomes a parallel light beam after being folded to the off-axis three-mirror 4. The light beam finally forms an image on the image plane after reaching the precision stabilization mirror 5. The system narrows the incident light beam and provides a parallel optical path for subsequent imaging components, which can effectively reduce the aperture size of subsequent optical components. Its pre-placed Cartesian system can enlarge the aperture, and the aberration of the Cartesian system is compensated by the subsequent off-axis three-mirror 4 to form a large-aperture, large-magnification telescopic optical system. In order to reduce the difficulty of adjustment, the mirror normal of the folding axis reflector 3 is designed to be at an angle of 45° with the optical axis, and the actual optical axis of the off-axis three-mirror 4 is designed to be orthogonal to the optical axis of the primary and secondary mirrors. The system optimizes the system design by reasonably allocating the focal length of the aspheric primary mirror 1, the aspheric secondary mirror 2 and the off-axis three-mirror 4, so that the system aberration is effectively controlled. At the same time, the system makes full use of the space in the axial and vertical directions, greatly shortens the length of the optical tube, and makes the spatial configuration more compact. The above optical system has many advantages such as compact structure, wide spectral range, large aperture and long focal length, and image quality that can approach and reach the diffraction limit.

[0062] like Figure 2-8 As shown, the embodiment of the present application provides a compact folding axis multi-reflection optical system assembly method, the method comprising the following steps:

[0063] S1: With the help of the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer frame docking outer circle and end surface of the aspheric primary mirror 1 are finely turned to obtain the calibrated aspheric primary mirror 1;

[0064] S2: With the help of the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer frame docking outer circle and end surface of the aspheric secondary mirror 2 are finely turned to obtain the calibrated aspheric secondary mirror 2;

[0065] S3: Assemble the aspheric primary mirror 1 obtained in S1 and the aspheric secondary mirror 2 obtained in S2 to obtain the primary and secondary mirror components, complete the establishment of the spatial orthogonal reference position of the folding axis reflector 3 with the help of the self-collimating light tube, and adjust the angular deviation of the folding axis reflector 3 until the reference requirement is met;

[0066] S4: The system optical axis composed of the aspheric primary mirror 1 determined by S1 and the aspheric secondary mirror 2 determined by S2 is used to establish the spatial orthogonal reference position with the help of a self-collimating light pipe, and the angular deviation of the off-axis three mirrors 4 is adjusted until the reference requirements are met;

[0067] S5: A sensitivity matrix model is established through the misalignment element, the Zernike coefficient of the entire system is measured by a laser interferometer, the misalignment of the optical element is reversely calculated, and the translation position of the folding axis reflector 3 and the off-axis three mirrors 4 is finely adjusted to complete the assembly.

[0068] In the adjustment method provided in the above-mentioned embodiment, the aspheric surface centering detection and turning processing are functionally combined, and the adjustment of the aspheric primary and secondary mirrors is transformed from the traditional adjustment of the aspheric optical element to the centering turning outer frame structure, thereby realizing the rapid centering turning and assembly of the primary and secondary mirrors. The angular deviation of the folding axis reflector and the off-axis three mirrors is adjusted by the photoelectric self-collimating light tube, the adjustment freedom of the two optical components is reduced, the adjustment error of the system is controlled within the linear range of the computer-aided adjustment sensitivity matrix, and the laser interferometer and the standard plane mirror are used to complete the precise adjustment of the folding axis reflector and the off-axis three mirrors. The present invention realizes the centering guarantee of the mechanical axis and the optical axis in the primary and secondary mirror adjustment stage, and subsequently effectively separates the adjustment dimensions of the folding axis mirror and the three mirrors, reducing the difficulty of subsequent computer-aided adjustment, ensuring the assembly accuracy, and greatly improving the adjustment efficiency of the optical system.

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

[0070] S1.1: placing the aspheric primary mirror 1 in the primary mirror outer frame 6, inserting a plurality of gaskets around the aspheric primary mirror 1 for rough centering, and curing and connecting the aspheric primary mirror 1 and the primary mirror outer frame 6 by pouring adhesive to obtain an initial primary mirror assembly in which the aspheric primary mirror 1 and the primary mirror outer frame 6 are fixedly connected;

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

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

[0073] S1.4: Use the centering device 9 to observe the circle drawing amount of the spherical center image of the aspherical primary mirror 1, use the chromatic aberration displacement sensor 8 to observe the runout of the outer ring of the aspherical primary mirror 1, determine the position of the optical axis of the aspherical primary mirror 1, adjust the rotation processing spindle angle and translation amount, so that the optical axis of the aspherical primary mirror 1 coincides with the axis of the turntable;

[0074] S1.5: Use a turning tool to turn the outer circle a surface and the end surface b surface of the main mirror outer frame 6 to ensure that the docking axis of the main mirror outer frame 6 coincides with the optical axis;

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

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

[0077] S2.1: placing the aspheric secondary mirror 2 in the secondary mirror outer frame 11, inserting a plurality of gaskets around the aspheric secondary mirror 2 for rough centering, and curing and connecting the aspheric secondary mirror 2 and the secondary mirror outer frame 11 by pouring adhesive to obtain an initial secondary mirror assembly in which the aspheric secondary mirror 2 and the secondary mirror outer frame 11 are fixedly connected;

[0078] S2.2: Place the secondary mirror initial assembly body in the center on the rotary processing spindle 7, and connect the rotary processing spindle 7 to the turntable tightly;

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

[0080] S2.4: Use the centering device 9 to observe the amount of the secondary mirror fitting spherical center image drawing circle, use the chromatic aberration displacement sensor 8 to observe the amount of runout of the outer ring of the aspherical secondary mirror 2, determine the position of the optical axis of the aspherical secondary mirror 2, adjust the angle and translation of the rotary processing spindle 7, so that the optical axis of the aspherical secondary mirror 2 coincides with the axis of the turntable;

[0081] S2.5: Use a turning tool to turn the outer circle a surface and the end surface 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 turning in S2.5. If it is qualified, the turning of the aspherical secondary mirror 2 is completed.

[0083] In some embodiments, the S3 includes:

[0084] S3.1: erecting a first photoelectric self-collimating light tube 12, placing a pentaprism 13 on the same horizontal plane as the first photoelectric self-collimating light tube 12, and adjusting the azimuth and elevation angles of the pentaprism 13 to align it with the first photoelectric self-collimating light tube 12;

[0085] S3.2: Set up a second photoelectric self-collimating light tube 14 along the light beam exiting direction of the pentaprism 13, adjust the second photoelectric self-collimating light tube 14 so that it is aligned with the light beam exiting the pentaprism 13, and the first photoelectric self-collimating light tube 12 and the second photoelectric self-collimating light 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 platform 16, and adjust the multi-dimensional adjustment platform 16 in the spatial orthogonal rectangular coordinate system obtained in S3.2 to align the back surface of the secondary mirror in the primary and secondary mirror components with the first photoelectric self-collimation light 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 of the platform frame 15, and adjust the angular deviation position of the folding axis reflector 3 through the adjustment reference established by the first photoelectric autocollimation light tube 12 and the second photoelectric autocollimation light tube 14, so that the first photoelectric autocollimation light tube 12 and the second photoelectric autocollimation light tube 14 are aligned through the folding axis reflector 3, and the angular deviation adjustment of the folding axis reflector 3 is completed.

[0088] In some embodiments, the 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: Detecting the optical axis position by the first photoelectric self-collimating light tube 12;

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

[0092] In some embodiments, the S5 includes:

[0093] S5.1: self-align the standard plane mirror 18 and the large aperture interferometer 17;

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

[0095] S5.3: Install the precision stabilizing mirror 5 so that the light beam is parallel to the incident light;

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

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

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

[0099] S5.7: Use a large-aperture interferometer 17 to measure the Zerni ke coefficient of the entire optical system and inversely calculate the misalignment of the optical element;

[0100] S5.8: Finely adjust the translational position of the folding axis reflector 3 and the off-axis three mirrors 4 and the angular deviation of the precision stabilization mirror to complete the assembly of the optical system.

[0101] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A method for assembling a compact folding-axis multi-reflection optical system, the compact folding-axis multi-reflection optical system comprising an aspheric primary mirror, an aspheric secondary mirror coaxial with the aspheric primary mirror and forming a primary image point, a folding-axis reflector located after the primary image point, an off-axis three-mirror for folding a light beam whose exit direction is changed by the folding-axis reflector into a parallel light beam, and a precision stabilizing mirror for final imaging, characterized in that: The method comprises the following steps: S1: With the help of the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer frame docking outer circle and end surface of the aspheric primary mirror are finely turned to obtain the aspheric primary mirror; S2: With the help of the internal focusing light tube, chromatic aberration displacement sensor and its own turning system of the automatic centering lathe, the outer frame docking outer circle and end surface of the aspheric secondary mirror are finely turned to obtain the aspheric secondary mirror; S3: Assemble the aspheric primary mirror obtained in S1 and the aspheric secondary mirror obtained in S2 to obtain the primary and secondary mirror components, complete the establishment of the spatial orthogonal reference position of the folding axis reflector with the help of the self-collimating light tube, and adjust the angular deviation of the folding axis reflector until the reference requirements are met; S4: The system optical axis composed of the aspheric primary mirror determined by S1 and the aspheric secondary mirror determined by S2 is used to establish the spatial orthogonal reference position with the help of a self-collimating light pipe, 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 misalignment element, use laser interferometer to measure the Zernike coefficient of the whole system, reversely calculate the misalignment of the optical element, finely adjust the translation position of the folding axis reflector and the off-axis three mirrors, and complete the assembly.

2. The compact folding axis multi-reflection optical system assembly method according to claim 1, characterized in that: The S1 includes: S1.1: Place the aspheric primary mirror in the primary mirror frame, insert a plurality of gaskets around the aspheric primary mirror for rough centering, and solidify and connect the aspheric primary mirror and the primary mirror frame by pouring adhesive to obtain an initial primary mirror assembly in which the aspheric primary mirror and the primary mirror frame are fixedly connected; S1.2: Place the primary mirror initial assembly in the center on the rotary processing spindle, and connect the rotary processing spindle to the turntable tightly; S1.3: Measure the outer circle and end face runout of the main mirror frame, and adjust the position and tilt angle of the rotary machining spindle until the outer circle and end face runout of the main mirror frame is no more than 0.05mm; S1.4: Use a centering instrument to observe the amount of the aspheric primary mirror fitting the spherical center image to draw a circle, observe the amount of runout of the outer ring of the aspheric primary mirror, determine the position of the optical axis of the aspheric primary mirror, and adjust the angle and translation of the rotary machining spindle so that the optical axis of the aspheric primary mirror coincides with the axis of the turntable; S1.5: Use a turning tool to turn the outer circle and end face of the main mirror frame to ensure that the main mirror frame docking axis coincides with the optical axis; S1.6: Re-inspect the outer frame of the primary mirror after turning in S1.

5. If it passes the inspection, the turning of the aspherical primary mirror is completed.

3. The compact folding axis multi-reflection optical system assembly and adjustment method according to claim 1, characterized in that: The S2 includes: S2.1: placing the aspheric secondary mirror in the secondary mirror outer frame, inserting a plurality of gaskets around the aspheric secondary mirror for rough centering, and curing and connecting the aspheric secondary mirror and the secondary mirror outer frame by pouring adhesive to obtain an initial secondary mirror assembly in which the aspheric secondary mirror and the secondary mirror outer frame are fixedly connected; S2.2: Place the secondary mirror initial assembly in the center on the rotary processing spindle, and connect the rotary processing spindle to the turntable tightly; S2.3: Measure the outer circle and end face runout of the secondary mirror frame, and adjust the position and tilt angle of the rotary machining spindle until the outer circle and end face runout of the secondary mirror frame is no more than 0.05mm; S2.4: Use a centering instrument to observe the amount of the secondary mirror fitting spherical center image drawing circle, observe the amount of runout of the outer ring of the aspherical secondary mirror, determine the position of the optical axis of the aspherical secondary mirror, 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 turning tool to turn the outer circle and end face of the secondary mirror frame to ensure that the docking axis of the secondary mirror frame coincides with the optical axis; S2.6: Re-inspect the secondary mirror frame after turning in S2.

5. If it passes the inspection, the turning of the aspherical secondary mirror is completed.

4. The compact folding axis multi-reflection optical system assembly and adjustment method according to claim 1, characterized in that: The S3 includes: S3.1: Set up a first photoelectric autocollimation light tube, place a pentaprism on the same horizontal plane as the first photoelectric autocollimation light tube, and adjust the azimuth and elevation angles of the pentaprism to align it with the first photoelectric autocollimation light tube; S3.2: Set up a second photoelectric autocollimation light tube along the direction of the pentaprism light beam, adjust the second photoelectric autocollimation light tube to align it with the pentaprism light beam, and the first photoelectric autocollimation light tube and the second photoelectric autocollimation light 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 table, and adjust the multi-dimensional adjustment table in the spatial orthogonal rectangular coordinate system obtained in S3.2 to align the back surface of the secondary mirror in the primary and secondary mirror components with the first photoelectric self-collimation light tube; S3.4: Remove the primary and secondary mirror components from the platform frame, install the folding axis reflector at the theoretical position of the platform frame, and adjust the angular deviation position of the folding axis reflector through the adjustment reference established by the first photoelectric autocollimation light tube and the second photoelectric autocollimation light tube, so that the first photoelectric autocollimation light tube and the second photoelectric autocollimation light tube complete the alignment through the folding axis reflector, thereby completing the angular deviation adjustment of the folding axis reflector.

5. The compact folding axis multi-reflection optical system assembly and adjustment method according to claim 1, characterized in that: The S4 includes: S4.1: Install the primary and secondary mirror components onto the platform frame and install the off-axis three mirrors; S4.2: Detecting the optical axis position by a first photoelectric self-collimating light tube; S4.3: Observe the back reference of the off-axis three mirrors through the second photoelectric self-collimation light tube, adjust the angular deviation of the off-axis three mirrors, and complete the angular deviation adjustment of the off-axis three mirrors.

6. The compact folding axis multi-reflection optical system assembly and adjustment method according to claim 1, characterized in that: The S5 includes: S5.1: Self-align a standard plane mirror with a large aperture interferometer; S5.2: Adjust the multi-dimensional adjustment stage to the front of the large-aperture interferometer; S5.3: Install the precision stabilization mirror so that the light beam is parallel to the incident light; S5.4: A standard plane mirror is set behind the precision stabilization mirror to receive the light beam for interference detection; S5.5: Adjust the position angle of the multi-dimensional adjustment stage to align the large-aperture interferometer with the back reference of the aspheric secondary mirror; S5.6: Determine the 0° field of view incident light axis of the entire optical system and establish a sensitivity matrix model through misalignment elements; S5.7: Use a large-aperture interferometer to measure the Zernike coefficients of the entire optical system and inversely calculate the misalignment of the optical components; S5.8: Finely adjust the translational position of the folding mirror and the off-axis three mirrors and the angular deviation of the precision stabilization mirror to complete the assembly of the optical system.

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