CN115718356A - Precise assembly method of off-axis two-mirror and lens combined optical system - Google Patents
Precise assembly method of off-axis two-mirror and lens combined optical system Download PDFInfo
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Abstract
The invention discloses a precise assembly method of an off-axis two-reflector and lens combined optical system, which mainly solves the technical problems that the existing off-axis two-reflector and lens combined optical system is of a non-rotational symmetric structure, the optical axes of all components are not coaxial, the high-precision assembly and adjustment can not be realized by adopting the traditional coaxial system assembly and adjustment method, and great difficulty is brought to the assembly and adjustment. The method comprises the following steps: step 1, precise positioning installation of a primary mirror assembly and establishment of a reference coordinate system; step 2, calibrating the optical axis of the primary mirror; step 3, precisely positioning and installing the secondary mirror assembly; step 4, detecting the image quality of the primary mirror system and the secondary mirror system; step 5, precisely positioning and installing the lens assembly; and 6, detecting the image quality of the optical system. The method greatly improves the initial assembly precision of the optical system, simplifies the assembly process and plays a great auxiliary role in fine adjustment of the optical structure of the optical system.
Description
Technical Field
The invention relates to an optical-mechanical assembly method of an optical system, in particular to a precise assembly method of an off-axis two-mirror and lens combined optical system.
Background
The reflective optical system is a structural form commonly adopted in modern space-based and space-based large-aperture telescopes and comprises a coaxial reflective optical system and an off-axis reflective optical system; the coaxial reflective optical system has central shielding, so that not only is light energy lost, but also the response at the middle and low frequency is reduced, and the observation performance of the system is limited; compared with a coaxial reflective optical system, the off-axis reflective optical system is not mutually shielded, a larger effective caliber can be realized under the same volume constraint, the edge scattering effect is avoided, the system has higher energy concentration and dynamic range, and the high-resolution limit detection requirement can be better met.
The off-axis two-mirror and lens combined optical system is a typical off-axis reflective optical system, has the advantages of an off-axis system, and is provided with a lens assembly at the rear end, so that the effective field of view and the imaging quality of the optical system are enlarged, and the performance of the optical system is integrally improved.
However, the existing off-axis two-mirror and lens combined optical system is of a non-rotational symmetric structure, the optical axes of the components are not coaxial, and the high-precision assembly and adjustment cannot be realized by adopting the traditional coaxial system assembly and adjustment method, so that great difficulty is brought to the assembly and adjustment.
Disclosure of Invention
The invention aims to solve the technical problems that the existing off-axis two-mirror and lens combined optical system is in a non-rotational symmetric structure, the optical axes of all components are not coaxial, the high-precision assembly and adjustment cannot be realized by adopting the traditional coaxial system assembly and adjustment method, and great difficulty is brought to the assembly and adjustment, and provides a precise assembly method of the off-axis two-mirror and lens combined optical system.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a precise assembly method of an off-axis two-mirror and lens combined optical system comprises a primary mirror assembly, a secondary mirror assembly, a lens assembly, a diaphragm, a telescopic assembly and a bottom plate; the method is characterized by comprising the following steps:
establishing a reference coordinate system by taking the main mirror as a reference;
and 6, detecting the wave aberration of the primarily assembled optical system, adjusting the lens support according to the detection result, and repeatedly detecting and adjusting until the wave aberration of the optical system meets the requirement, thereby finishing the final assembly of the optical system.
Further, the step 1 is specifically implemented according to the following steps:
step 1.1, preliminarily assembling a main mirror assembly on a bottom plate, and respectively constructing a reference surface A and a reference surface B as installation references of a main mirror; defining the back surface of the main mirror as a reference surface C; respectively measuring the included angles of the reference surface C and the reference surfaces A and B;
step 1.2, adjusting the pitch angle of the primary mirror according to the measurement result of the included angle between the reference plane C and the reference plane B until the actual measured included angle between the reference plane C and the reference plane B is within a deviation range compared with the theoretical included angle between the reference plane C and the reference plane B; adjusting the azimuth angle of the primary mirror according to the measurement result of the included angle between the reference plane C and the reference plane A until the actual measured included angle between the reference plane C and the reference plane A is within a deviation range compared with the theoretical included angle between the reference plane C and the reference plane A;
step 1.3, measuring the reference surface C and the excircle axis of the primary mirror to obtain an intersection point O, determining the Y-axis direction of a coordinate system by taking the intersection point O as a coordinate origin, the normal of the reference surface B as the Z-axis direction of the coordinate system, the normal of the reference surface A as the X-axis direction of the coordinate system and the X-axis direction and the Z-axis direction according to a right-hand rule, and establishing a reference coordinate system O { XYZ }.
Further, the step 2 is specifically implemented according to the following steps:
step 2.1, constructing a main mirror surface shape interference detection light path by using an interferometer and a standard plane reflector with the main mirror as a reference;
step 2.2, detecting the surface shape data of the primary mirror, adjusting the angle of the standard plane reflector and translating the interferometer by taking the surface shape data of the primary mirror as a reference, and adjusting the normal of the standard plane reflector to a position parallel to the optical axis of the primary mirror;
and 2.3, completing the calibration of the optical axis of the primary mirror.
Further, the step 3 is specifically implemented according to the following steps:
step 3.1, preliminarily assembling the secondary mirror assembly on a bottom plate;
step 3.2, defining the back surface of the secondary mirror as a reference surface D, and respectively measuring included angles between the reference surface D and the reference surfaces B and C; adjusting the pitch angle of the secondary mirror according to the measurement result of the included angle between the reference surface D and the reference surface B until the actual measured included angle between the reference surface D and the reference surface B is within an error range compared with the theoretical included angle between the reference surface D and the reference surface B; adjusting the azimuth angle of the secondary mirror according to the measurement result of the included angle between the reference surface D and the reference surface C until the actual measured included angle between the reference surface D and the reference surface C is within an error range compared with the theoretical included angle between the reference surface D and the reference surface C;
step 3.3, measuring the reference surface D and the excircle axis of the secondary mirror to obtain an intersection point O 1 Based on the origin of coordinates O of the reference coordinate system and based on the intersection O 1 The position of the secondary mirror on the reference coordinate system is adjusted by the theoretical deviation from the origin of coordinates O, so that the adjusted intersection point O is ensured 1 The actual deviation from the origin of coordinates O is within the deviation range;
step 3.4, judging whether the azimuth angle, the pitch angle and the eccentric position of the secondary mirror are all in the deviation range; if not, returning to the step 3.2 until the azimuth angle, the pitch angle and the eccentric position of the secondary mirror are all in the deviation range; and if so, finishing the primary assembly of the primary and secondary mirror systems.
Further, the step 5 is specifically implemented according to the following steps:
step 5.1, preliminarily assembling the lens assembly on a bottom plate;
step 5.2, defining the mounting end face of the lens support as a reference plane E, respectively measuring included angles between the reference plane E and the reference planes B and C, and adjusting the pitch angle of the lens support according to the measurement result of the included angle between the reference plane E and the reference plane B until the actual measured included angle between the reference plane E and the reference plane B is within a deviation range compared with the theoretical included angle between the reference plane E and the reference plane B; adjusting the azimuth angle of the lens support according to the measurement result of the included angle between the reference plane E and the reference plane C until the actual measurement included angle between the reference plane E and the reference plane C is within the deviation range compared with the theoretical included angle between the reference plane E and the reference plane C;
step 5.4, judging whether the pitch angle, the azimuth angle and the eccentric position of the lens support are all in the deviation range; if not, returning to the step 5.2 until the pitch angle, the azimuth angle and the eccentric position of the lens support are adjusted to be within the deviation range; if yes, the preliminary assembly of the optical system is completed.
Further, in step 4, an interferometer and a standard plane mirror are used for building an image quality detection light path of the primary mirror system and the secondary mirror system, and wave aberration of the primary mirror system and the secondary mirror system is detected through the interferometer;
in step 6, an image quality detection optical path of the optical system is constructed by using an interferometer and a standard plane mirror, and the wave aberration of the optical system is detected by the interferometer.
Further, in step 4, the detection result output by the interferometer is defined as α 1 The adjustment amount of the secondary mirror is L 1 Then α is 1 And L 1 Satisfies the following formula
L 1 ＝(M T M) -1 M T α 1 ；
In the formula: m is a secondary mirror sensitivity matrix; m T Transpose the matrix for M;
in step 6, the detection result output by the interferometer is defined as alpha 2 The lens holder is adjusted by an amount L 2 Then α is 2 And L 2 Satisfies the following formula:
L 2 ＝(N T N) -1 N T α 2 ；
in the formula: n is the sensitivity matrix of the lens holder; n is a radical of hydrogen T Is a matrix transpose of N.
Further, before step 1, the method also comprises the following steps:
and 01, mounting an external flexible articulated arm measuring instrument on the bottom plate for measuring an included angle, measuring an eccentric position, constructing a mounting reference, determining an intersection point and constructing a reference coordinate system.
Compared with the prior art, the invention has the beneficial effects that:
1. firstly, establishing a reference coordinate system according to a theoretical model, then carrying out preliminary assembly by taking the theoretical position of the characteristics (points, lines and surfaces) of the parts to be assembled under the reference coordinate system as a reference, and carrying out fine adjustment according to the spatial position of the characteristics of the parts to be assembled until the parts are adjusted to the theoretical positions of the parts to be assembled, thereby completing the high-precision assembly and adjustment of the parts; finally, the final assembly of the system is completed by detecting and adjusting the image quality; the method greatly improves the assembly precision of the system and simplifies the assembly process.
2. According to the invention, the adjustment quantity of the sensitivity freedom degree of the element to be adjusted can be obtained by inputting the image quality measurement result, and the adjustment is carried out according to the calculation result, so that the imaging quality of the optical system can be ensured to meet the requirements, blind adjustment is avoided, and the assembly efficiency and scientificity of the optical system are greatly improved.
Drawings
FIG. 1 is a schematic diagram of an off-axis two-mirror and lens combined optical system;
FIG. 2 is a schematic diagram of a primary mirror mounting reference and reference coordinate system in an embodiment of the present invention;
FIG. 3 is a schematic diagram illustrating a calibration principle of an optical axis of a primary mirror according to an embodiment of the present invention;
FIG. 4 is a schematic illustration of a secondary mirror mounting datum in an embodiment of the present invention;
FIG. 5 is a schematic diagram of an image quality detection optical path of the primary and secondary mirror systems in an embodiment of the present invention;
FIG. 6 is a schematic illustration of a lens holder mounting datum in an embodiment of the invention;
fig. 7 is a schematic diagram of an image quality detection optical path of an optical system in an embodiment of the present invention.
In the figure:
01-interferometer, 02-standard plane mirror;
1-a primary mirror component, 2-a secondary mirror component, 3-a lens component, 4-a diaphragm, 5-a telescopic component and 6-a bottom plate.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, an off-axis two-mirror and lens combined optical system includes a primary mirror assembly 1, a secondary mirror assembly 2, a lens assembly 3, a diaphragm 4, an invar telescopic assembly 5 and a bottom plate 6; the primary mirror assembly 1 is connected with a bottom plate 6 through an invar telescopic assembly 5, and a primary mirror is assembled in a primary mirror frame in the primary mirror assembly 1; the secondary mirror assembly 2 is connected with the bottom plate 6 through an invar steel telescopic assembly 5, and the secondary mirror is assembled in a secondary mirror frame in the secondary mirror assembly 2; the lens support is arranged on the lens support, and a lens optical lens group is arranged in the lens support; the base plate 6 provides a base mounting reference for all structures.
Parallel light enters the optical system through the diaphragm 4 and passes through the primary mirror assembly 1, the secondary mirror assembly 2 and the lens assembly 3 in sequence to form perfect images at a rear end focus. The optical system is configured to ensure that the image quality at the focal point is such that the central field of view RMS is better than 0.085 λ @632.8nm and the + -1 ° field of view RMS is better than 0.014 λ @632.8nm. According to the optical tolerance analysis, in order to ensure that the optical index of the optical system meets the requirement, the position error of each component is better than 0.05mm, the angle error is better than 1', otherwise, the optical system generates serious aberration and cannot be used. The traditional mechanical assembly precision is low, and the assembly requirements of the system cannot be met; aiming at the existing off-axis two-mirror and lens combined optical system, the invention provides a precision assembly method, which utilizes a flexible articulated arm measuring instrument to ensure that the position error and the angle error meet the requirements, and finally uses the interference detection principle to finely adjust a sensitive element to ensure the imaging quality of the optical system.
Based on the optical system structure, the invention discloses a precise assembly method of an off-axis two-mirror and lens combined optical system, which comprises the steps of firstly, installing an external flexible joint arm measuring instrument on a bottom plate 6, enabling the whole to-be-assembled optical system to be in the detection range, enabling the spatial positioning precision of the measuring instrument to be 0.02mm, meeting the precision requirement of the optical system assembly of 0.05mm, and being used for measuring an included angle, measuring an eccentric position, constructing an installation reference, determining an intersection point and constructing a reference coordinate system;
then the method is implemented according to the following steps;
step 1.1, preliminarily assembling a main mirror assembly 1 on a bottom plate 6 through a threaded hole formed in the bottom plate 6, wherein the main mirror is an off-axis parabolic mirror, high and low point score marks are reserved during optical processing, and the consistency of high and low point scores is ensured during assembly; the main mirror is rotated around the bracket, the height gauge is used for measuring the high and low point mark lines to ensure that the two scribed lines are at the same height, and the deviation is controlled within 0.05 mm;
as shown in fig. 2, a reference plane a and a reference plane B are respectively constructed as mounting references of the primary mirror using the flexible joint robot arm measuring instrument; defining the back of the primary mirror as a reference surface C, and respectively measuring included angles between the reference surface C and the reference surfaces A and B;
step 1.2, adjusting the pitch angle of the primary mirror according to the measurement result of the included angle between the reference plane C and the reference plane B until the actual measured included angle between the reference plane C and the reference plane B is within the deviation range compared with the theoretical included angle between the reference plane C and the reference plane B, and in the embodiment, ensuring that the included angle between the reference plane C and the reference plane B is 90 degrees +/-1'; adjusting the azimuth angle of the primary mirror according to the measurement result of the included angle between the reference plane C and the reference plane a until the actual measured included angle between the reference plane C and the reference plane a is within a deviation range compared with the theoretical included angle between the reference plane C and the reference plane a, in this embodiment, the included angle between the primary reference plane C and the reference plane a is ensured to be 17.39 degrees +/-1', and the final assembly of the primary mirror assembly 1 is completed;
step 1.3, the space angle between the main mirror assembly 1 and the bottom plate 6 is ensured through the steps, and other subsequent assemblies take the main mirror as a reference, and the precision control position deviation is superior to the assembly requirement that the angle deviation is less than 1' and is 0.05 mm; therefore, after the primary mirror assembly 1 is positioned, a coordinate system needs to be established on the primary mirror to be used as an assembly reference of subsequent assemblies;
and measuring the axis of the reference surface C and the excircle of the primary mirror by using a flexible joint arm measuring instrument to obtain an intersection point O, determining the Y-axis direction of the coordinate system by using the intersection point O on the primary mirror as a coordinate origin, the normal of the reference surface B as the Z-axis direction of the coordinate system and the normal of the reference surface A as the X-axis direction of the coordinate system according to the right-hand rule and the X-axis direction and the Z-axis direction, and establishing a reference coordinate system O { XYZ }.
step 2.1, taking the main mirror as a reference, and building a main mirror surface-shaped interference detection light path by using a 4D interferometer 01 and a standard plane reflector 02, as shown in FIG. 3; the standard plane mirror 02 is used for the heaviest image quality measurement of an optical system, and the normal line of the standard plane mirror is ensured to be parallel to the optical axis of the primary mirror precisely; measuring the mirror surface of the standard plane reflector 02 by using a flexible joint mechanical arm measuring instrument, ensuring that the parallel error with the reference surface A is better than 1', and preliminarily positioning the angle posture of the standard plane reflector 02;
2.2, detecting the surface shape of the main mirror through a flexible joint mechanical arm measuring instrument, outputting main mirror surface shape detection data, adjusting the angle of the standard plane reflecting mirror 02 and translating the interferometer 01 by taking the main mirror surface shape detection data as a reference, ensuring that the astigmatic coefficients in the X direction and the Y direction are minimum, ensuring that the surface shape RMS is superior to 1/60 lambda @632.8nm, and adjusting the normal of the standard plane reflecting mirror 02 to a position parallel to the optical axis of the main mirror;
and 2.3, completing the calibration of the optical axis of the primary mirror.
And 3, precisely positioning and installing the secondary mirror assembly 2, and specifically implementing according to the following steps:
3.1, preliminarily assembling the secondary mirror assembly 2 onto the bottom plate 6 through a threaded hole in the bottom plate 6, wherein the secondary mirror is an off-axis hyperboloid warp, reserving a high-low point scribing standard during optical processing, ensuring that high-low point scribing is consistent during assembly, spinning the secondary mirror around a support of the secondary mirror, measuring high-low point marking lines by using a height gauge, ensuring that two scribing lines are at the same height, and controlling the deviation to be 0.05 mm;
step 3.2, defining the back surface of the secondary mirror as a reference surface D, and respectively measuring included angles between the reference surface D and reference surfaces B and C by using a flexible joint mechanical arm measuring instrument, as shown in FIG. 4; adjusting the pitch angle of the secondary mirror according to the measurement result of the included angle between the reference plane D and the reference plane B until the actual measured included angle between the reference plane D and the reference plane B is within an error range compared with the theoretical included angle between the reference plane D and the reference plane B, and in the embodiment, the included angle between the reference plane D and the reference plane B is guaranteed to be 90 degrees +/-1'; adjusting the azimuth angle of the secondary mirror according to the measurement result of the included angle between the reference plane D and the reference plane C until the actual measured included angle between the reference plane D and the reference plane C is within an error range compared with the theoretical included angle between the reference plane D and the reference plane C, and in the embodiment, ensuring that the included angle between the reference plane D and the reference plane C at the back of the primary mirror is 34.46 degrees +/-1';
step 3.3, measuring the datum plane D and the secondary mirror excircle axis by using the flexible joint mechanical arm measuring instrument to obtain an intersection point O 1 (x 1 ,y 1 ,z 1 ) In the reference coordinate system O { XYZ } of the main mirror, the intersection O is determined based on the origin O of the reference coordinate system 1 The theoretical deviation from the coordinate origin O, the position of the secondary mirror on the reference coordinate system is adjusted through a translation adjusting frame mechanism on the secondary mirror assembly 2, and the adjusted intersection point O is ensured 1 The actual deviation from the origin of coordinates O is within the deviation range, in this embodiment, x is guaranteed 1 ＝383.56±0.05mm、y 1 ＝266.60±0.05mm、z 1 ＝±0.05mm；
Step 3.4, because the eccentric adjustment can influence the pitch angle and the azimuth angle of the secondary mirror, whether the azimuth angle, the pitch angle and the eccentric position of the secondary mirror are all in the deviation range needs to be judged; if not, returning to the step 3.2 until the azimuth angle, the pitch angle and the eccentric position of the secondary mirror are all in the deviation range; if so, finishing the initial assembly of the primary mirror system and the secondary mirror system.
And 4, when the curvature radius, the aspheric surface coefficient and the like of the optical element have deviations, the imaging quality of the optical system cannot be ensured to meet the requirements only after the optical component is assembled according to the theoretical position. The angle of the secondary mirror assembly 2 is very sensitive to the effect of the substrate, according to the aberration characteristics analysis. Therefore, interferometer 01 is used to detect the wave aberration of the primary and secondary mirrors, and the position of the secondary mirror is adjusted slightly according to the measurement result, so that the primary and secondary systems have good imaging quality.
Formula (1) is the secondary lens freedom and the aberration coefficient Z of the primary and secondary lens system 5 ～Z 9 Mathematical relationship of terms, degree of freedom of secondary mirror in coordinate system O in FIG. 6 1 {X 1 Y 1 Z 1 On a basis of d x 、d y 、d z Represents along X 1 、Y 1 、Z 1 Translation of (a), t x 、t y Represents around X 1 、Y 1 The rotation of (2). The azimuth angle and the pitch angle t of the secondary mirror can be known by analysis x 、t y It is most sensitive, with the greatest impact on the quality and the other degrees of freedom being less.
A 4D interferometer 01 and a standard plane mirror 02 are used for building a primary mirror system and a secondary mirror system to detect a light path, as shown in FIG. 5; the normal phase of the plane mirror is the direction of the optical axis of the primary mirror, and calibration is completed in step 2. Measuring the coefficient alpha from the image quality 1 Calculating an adjustment amount L of the secondary mirror using the formula (2) 1 According to X 1 And (4) measuring by using a flexible articulated arm measuring instrument, and precisely adjusting the secondary mirror. The analysis shows that the wave front Zernike coefficient term Z of the primary and secondary mirror system 5 、Z 6 The azimuth angle t of the secondary mirror being the main aberration x Influence Z 5 Coefficient of term, pitch angle t y Influence Z 6 The term coefficients, other degrees of freedom, have little effect on the quality. Thus, the pitch and azimuth angles of the secondary mirror are adjusted so that Z 5 、Z 6 The coefficient is minimum, the RMS of the primary mirror system and the secondary mirror system can be finally ensured to be better than 0.065 lambda @632.8nm, and the final assembly of the secondary mirror assembly and the primary mirror system and the secondary mirror system is completed after the image quality meets the requirement.
L 1 ＝(M T M) -1 M T α 1 ；(2)
In the formula: m is a secondary mirror sensitivity matrix; m T Transpose the matrix for M;
and step 5, precisely positioning and installing the lens assembly 3, and specifically implementing the following steps:
step 5.1, preliminarily assembling the lens assembly 3 on the bottom plate 6 through the threaded hole on the bottom plate 6;
step 5.2, defining the installation end face of the lens support as a reference plane E, and respectively measuring included angles between the reference plane E and reference planes B and C by using a flexible joint measuring instrument, as shown in FIG. 6; adjusting the pitch angle of the lens support according to the measurement result of the included angle between the reference plane E and the reference plane B until the actual measured included angle between the reference plane E and the reference plane B is within the deviation range compared with the theoretical included angle between the reference plane E and the reference plane B, and in the embodiment, the included angle between the reference plane E and the reference plane B is ensured to be 90 +/-1'; adjusting the azimuth angle of the lens support according to the measurement result of the included angle between the reference plane E and the reference plane C until the actual measured included angle between the reference plane E and the reference plane C is within the deviation range compared with the theoretical included angle between the reference plane E and the reference plane C, and in the embodiment, ensuring that the included angle between the reference plane E and the reference plane C on the back of the primary mirror is 51.50 degrees +/-1';
step 5.3, measuring the reference plane E and the excircle axis of the lens support by using the flexible articulated arm measuring instrument to obtain an intersection point O 2 (x 2 ,y 2 ,z 2 ) In the reference coordinate system O { XYZ } of the main mirror, according to the intersection O 2 The position of the lens support on the reference coordinate system is adjusted through a translation adjusting mechanism in the lens component 3 according to the theoretical deviation from the coordinate origin O, so that the adjusted intersection point O is ensured 2 The actual deviation from the origin of coordinates O is within the deviation range, in this embodiment, x is guaranteed 2 ＝-351±0.05mm、y 2 ＝132.23±0.05mm、z 2 = 0.05mm, completing the eccentric adjustment of the lens holder; because the inner hole of the lens support is matched with the excircle of the lens cone by a precise hole shaft, and the diameter clearance is better than 0.02mm, the lens cone only needs to be installed on the lens support after the lens support is installed;
step 5.4, judging whether the pitch angle and the azimuth angle of the lens support and the eccentric position are all in the deviation range or not because the eccentric adjustment can affect the pitch angle and the azimuth angle of the lens support; if not, returning to the step 5.2 until the pitch angle, the azimuth angle and the eccentric position of the lens support are adjusted to be within the deviation range; if yes, the preliminary assembly of the optical system is completed.
Formula (3) is the degree of freedom of the lens assembly 3 and the system aberration coefficient Z 5 ～Z 9 Mathematical relationship of terms, degrees of freedom of the lens assembly 3 in the coordinate system O in fig. 7 2 {X 2 Y 2 Z 2 On a basis of d x 、d y 、d z Represents along X 1 、Y 1 、Z 1 Translation of (a), t x 、t y Represents around X 1 、Y 1 The rotation of (2). From the analysis, the azimuth angle t of the lens y And a pitch angle t x The method is most sensitive, has the largest influence on the image quality of the system, and has little influence on other degrees of freedom.
L 2 ＝(N T N) -1 N T α 2 ；(4)
In the formula: n is a sensitivity matrix of the lens holder; n is a radical of T Is a matrix transpose of N.
An image quality detection optical path of an optical system is constructed by using a 4D interferometer 01 and a standard plane reflector 02, as shown in FIG. 7; the normal phase of the standard plane mirror 02 is the main mirror optical axis direction, and calibration is completed in step 2. Measuring the coefficient alpha according to image quality 2 Calculating the lens adjustment L using the formula (4) 2 According to L 2 And (4) measuring by using a flexible articulated arm measuring instrument, and precisely adjusting the lens. The analysis shows that the wave front Zernike coefficient term Z of the optical system 5 、Z 6 The azimuth angle of the lens affects Z as a dominant aberration 5 Term coefficient, pitch angle influence Z 6 The term coefficients, other degrees of freedom, have little effect on the quality. Thus, only the pitch t of the lens needs to be adjusted x And azimuth angle t y So that Z is 5 、Z 6 The coefficient is minimum, and finally, the optical system can be ensuredThe RMS on the axis of the system is better than 0.085 lambda @632.8nm, the RMS of the field of view at 1 degree outside the axis is better than 0.14 lambda @632.8nm, and the final assembly of the optical system is completed after the image quality meets the requirement.
Claims (8)
1. A precise assembly method of an off-axis two-mirror and lens combined optical system comprises a primary mirror assembly (1), a secondary mirror assembly (2), a lens assembly (3), a diaphragm (4), a telescopic assembly (5) and a bottom plate (6);
the method is characterized by comprising the following steps:
step 1, preliminarily assembling a primary mirror assembly (1) on a bottom plate (6), and constructing an installation reference of a primary mirror in the primary mirror assembly (1); measuring and adjusting the pitch angle and the azimuth angle of the primary mirror according to the installation reference until the pitch angle and the azimuth angle of the primary mirror are within the deviation range of the installation reference, and finishing the final assembly of the primary mirror assembly (1); establishing a reference coordinate system by taking the main mirror as a reference;
step 2, calibrating the optical axis of the primary mirror;
step 3, preliminarily assembling the secondary mirror assembly (2) on a bottom plate (6); taking the primary mirror as a reference, measuring and adjusting the pitch angle and the azimuth angle of the secondary mirror in the secondary mirror assembly (2); measuring and adjusting the eccentric position of the secondary mirror in the reference coordinate system by taking the coordinate origin of the reference coordinate system as a reference; repeatedly measuring and adjusting the pitch angle, the azimuth angle and the eccentric position of the secondary mirror until the pitch angle, the azimuth angle and the eccentric position of the secondary mirror are within the deviation range of the theoretical position, and finishing the initial assembly of a primary mirror system consisting of the primary mirror assembly (1) and the secondary mirror assembly (2);
step 4, detecting wave aberration of the primary mirror system and the secondary mirror system, adjusting the secondary mirror according to the detection result, and repeating detection and adjustment until the finally detected wave aberration of the primary mirror system and the secondary mirror system meets the requirements, so as to complete final assembly of the secondary mirror assembly (2) and the primary mirror system;
step 5, preliminarily assembling the lens assembly (3) on a bottom plate (6); taking the primary mirror as a reference, measuring and adjusting the pitch angle and the azimuth angle of a lens support in the lens assembly (3); measuring and adjusting the eccentric position of the lens support in the reference coordinate system by taking the coordinate origin of the reference coordinate system as a reference; repeatedly measuring and adjusting the pitch angle, the azimuth angle and the eccentric position of the lens support until the pitch angle, the azimuth angle and the eccentric position of the lens support are within the deviation range of the theoretical position, and finishing the initial assembly of the optical system;
step 6, detecting the wave aberration of the primarily assembled optical system, adjusting the lens support according to the detection result, and repeatedly detecting and adjusting until the wave aberration of the optical system meets the requirement; the final assembly of the optical system is completed.
2. The method for precisely assembling an off-axis two-mirror and lens combined optical system according to claim 1, wherein the step 1 is specifically performed according to the following steps:
step 1.1, preliminarily assembling a main mirror assembly (1) on a bottom plate (6), and respectively constructing a reference surface A and a reference surface B as installation references of a main mirror; defining the back surface of the main mirror as a reference surface C; respectively measuring the included angles of the reference surface C and the reference surfaces A and B;
step 1.2, adjusting the pitch angle of the primary mirror according to the measurement result of the included angle between the reference plane C and the reference plane B until the actual measured included angle between the reference plane C and the reference plane B is within a deviation range compared with the theoretical included angle between the reference plane C and the reference plane B; adjusting the azimuth angle of the primary mirror according to the measurement result of the included angle between the reference plane C and the reference plane A until the actual measured included angle between the reference plane C and the reference plane A is within a deviation range compared with the theoretical included angle between the reference plane C and the reference plane A;
step 1.3, measuring the reference surface C and the excircle axis of the primary mirror to obtain an intersection point O, determining the Y-axis direction of a coordinate system by taking the intersection point O as a coordinate origin, the normal of the reference surface B as the Z-axis direction of the coordinate system, the normal of the reference surface A as the X-axis direction of the coordinate system and the X-axis direction and the Z-axis direction according to a right-hand rule, and establishing a reference coordinate system O { XYZ }.
3. The method for precisely assembling an off-axis two-mirror and lens combined optical system according to claim 2, wherein the step 2 is implemented by the following steps:
step 2.1, constructing a main mirror surface shape interference detection light path by using an interferometer (01) and a standard plane reflector (02) with the main mirror as a reference;
step 2.2, detecting the surface shape data of the main mirror, adjusting the angle of the standard plane reflector (02) and the translational interferometer (01) by taking the surface shape data of the main mirror as a reference, and adjusting the normal of the standard plane reflector (02) to be parallel to the optical axis of the main mirror;
and 2.3, completing the calibration of the optical axis of the primary mirror.
4. A method according to claim 3, wherein the step 3 is implemented by the following steps:
step 3.1, preliminarily assembling the secondary mirror assembly (2) on a bottom plate (6);
step 3.2, defining the back surface of the secondary mirror as a reference surface D, and respectively measuring included angles between the reference surface D and the reference surfaces B and C; adjusting the pitch angle of the secondary mirror according to the measurement result of the included angle between the reference surface D and the reference surface B until the actual measured included angle between the reference surface D and the reference surface B is within an error range compared with the theoretical included angle between the reference surface D and the reference surface B; adjusting the azimuth angle of the secondary mirror according to the measurement result of the included angle between the reference surface D and the reference surface C until the actual measured included angle between the reference surface D and the reference surface C is within an error range compared with the theoretical included angle between the reference surface D and the reference surface C;
step 3.3, measuring the reference surface D and the excircle axis of the secondary mirror to obtain an intersection point O 1 Based on the origin of coordinates O of the reference coordinate system and based on the intersection O 1 Adjusting the position of the secondary mirror on the reference coordinate system by theoretical deviation from the coordinate origin O to ensure the adjusted intersection point O 1 The actual deviation from the origin of coordinates O is within the deviation range;
step 3.4, judging whether the azimuth angle, the pitch angle and the eccentric position of the secondary mirror are all in the deviation range; if not, returning to the step 3.2 until the azimuth angle, the pitch angle and the eccentric position of the secondary mirror are all in the deviation range; and if so, finishing the primary assembly of the primary and secondary mirror systems.
5. The method for precisely assembling an off-axis two-mirror and lens combined optical system according to claim 4, wherein the step 5 is implemented by the following steps:
step 5.1, preliminarily assembling the lens assembly (3) on a base plate (6);
step 5.2, defining the installation end face of the lens support as a reference face E, respectively measuring the included angles of the reference face E with the reference face B and the reference face C, and adjusting the pitch angle of the lens support according to the measurement result of the included angle of the reference face E with the reference face B until the actual measured included angle of the reference face E with the reference face B is within the deviation range compared with the theoretical included angle of the reference face E with the reference face B; adjusting the azimuth angle of the lens support according to the measurement result of the included angle between the reference plane E and the reference plane C until the actual measurement included angle between the reference plane E and the reference plane C is within the deviation range compared with the theoretical included angle between the reference plane E and the reference plane C;
step 5.3, measuring the reference plane E and the excircle axis of the lens support to obtain an intersection point O 2 Based on the origin of coordinates O of the reference coordinate system and based on the intersection O 2 Adjusting the position of the lens support on the reference coordinate system by the theoretical deviation from the origin of coordinates O to ensure the adjusted intersection point O 2 The actual deviation from the origin of coordinates O is within the deviation range;
step 5.4, judging whether the pitch angle, the azimuth angle and the eccentric position of the lens support are all in the deviation range; if not, returning to the step 5.2 until the pitch angle, the azimuth angle and the eccentric position of the lens support are adjusted to be within the deviation range; if yes, the preliminary assembly of the optical system is completed.
6. A method of precision assembly of an off-axis two-mirror and lens combined optical system according to any of claims 1 to 5, further comprising:
in the step 4, a primary and secondary mirror system image quality detection light path is built by using an interferometer (01) and a standard plane reflector (02), and the wave aberration of the primary and secondary mirror system is detected by the interferometer (01);
in step 6, an image quality detection optical path of the optical system is constructed by using the interferometer (01) and the standard plane mirror (02), and the wave aberration of the optical system is detected by the interferometer (01).
7. A method as claimed in claim 6, wherein in step 4, the output of the interferometer (01) is defined as α 1 The secondary mirror is adjusted by an amount L 1 Then α is 1 And L 1 Satisfies the following formula:
L 1 ＝(M T M) -1 M T α 1 ；
in the formula: m is a secondary mirror sensitivity matrix; m is a group of T Transpose matrix for M;
in step 6, the detection result output by the interferometer (01) is defined as alpha 2 The lens holder is adjusted by an amount L 2 Then α is 2 And L 2 Satisfies the following formula:
L 2 ＝(N T N) -1 N T α 2 ；
in the formula: n is a sensitivity matrix of the lens holder; n is a radical of hydrogen T Is a matrix transpose of N.
8. The method of claim 7, further comprising, before step 1:
and step 01, mounting an external flexible articulated arm measuring instrument on a bottom plate (6) for measuring an included angle, measuring an eccentric position, constructing a mounting reference, determining an intersection point and constructing a reference coordinate system.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104360492A (en) * | 2014-11-24 | 2015-02-18 | 中国航空工业集团公司洛阳电光设备研究所 | Adjusting method of off-axis four-reflector optical system |
| US20180157016A1 (en) * | 2016-12-05 | 2018-06-07 | Tsinghua University | Off-axis aspheric three-mirror optical system |
| CN113031296A (en) * | 2021-03-24 | 2021-06-25 | 长春长光智欧科技有限公司 | Method for assembling and adjusting metal-based free-form surface three-reflection optical system capable of being assembled and adjusted quickly |
| CN113900271A (en) * | 2021-09-30 | 2022-01-07 | 河北汉光重工有限责任公司 | Optical lens turning reflector debugging device and method |
| CN113917669A (en) * | 2021-09-08 | 2022-01-11 | 中国科学院西安光学精密机械研究所 | Off-axis reflection type telescopic system and installation and adjustment detection device and method thereof |
-
2022
- 2022-11-02 CN CN202211363678.7A patent/CN115718356A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104360492A (en) * | 2014-11-24 | 2015-02-18 | 中国航空工业集团公司洛阳电光设备研究所 | Adjusting method of off-axis four-reflector optical system |
| US20180157016A1 (en) * | 2016-12-05 | 2018-06-07 | Tsinghua University | Off-axis aspheric three-mirror optical system |
| CN113031296A (en) * | 2021-03-24 | 2021-06-25 | 长春长光智欧科技有限公司 | Method for assembling and adjusting metal-based free-form surface three-reflection optical system capable of being assembled and adjusted quickly |
| CN113917669A (en) * | 2021-09-08 | 2022-01-11 | 中国科学院西安光学精密机械研究所 | Off-axis reflection type telescopic system and installation and adjustment detection device and method thereof |
| CN113900271A (en) * | 2021-09-30 | 2022-01-07 | 河北汉光重工有限责任公司 | Optical lens turning reflector debugging device and method |
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