CN109163663B - Manufacturing method of long-focus large-off-axis-amount off-axis paraboloid - Google Patents
Manufacturing method of long-focus large-off-axis-amount off-axis paraboloid Download PDFInfo
- Publication number
- CN109163663B CN109163663B CN201811056441.8A CN201811056441A CN109163663B CN 109163663 B CN109163663 B CN 109163663B CN 201811056441 A CN201811056441 A CN 201811056441A CN 109163663 B CN109163663 B CN 109163663B
- Authority
- CN
- China
- Prior art keywords
- axis
- paraboloid
- long
- focus
- amount
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/002—Measuring arrangements characterised by the use of optical techniques for measuring two or more coordinates
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/255—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures for measuring radius of curvature
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/26—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/26—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes
- G01B11/27—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes
- G01B11/272—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes using photoelectric detection means
Abstract
The invention belongs to the technical field of optical processing, and particularly relates to a method for manufacturing an off-axis paraboloid; in order to solve the technical problem of poor processing precision caused by low detection precision of the long-focus large off-axis amount off-axis paraboloid, the manufacturing method of the long-focus large off-axis amount off-axis paraboloid is provided; the virtual focus of the divergent lens and the image point of the off-axis two-mirror system are overlapped by adopting the off-axis two-mirror system, so that the length of the light path is effectively shortened; the length of the light path is further shortened and the width of the light path is compressed by matching with a standard spherical reflector and a standard plane reflector; in addition, the technical scheme effectively utilizes the image element of the CCD, increases the detection resolution of the detected workpiece, can effectively inhibit the adverse effect of air disturbance on the detection result, improves the interference detection precision and provides guarantee for processing the off-axis mirror meeting the technical requirements.
Description
Technical Field
The invention belongs to the technical field of optics, and particularly relates to a method for manufacturing an off-axis paraboloid.
Background
The off-axis parabolic reflector cannot be machined and ground on a mirror grinding machine according to the traditional method because the rotational symmetry of the off-axis parabolic reflector is lost. It is generally accepted that only computer aided machining methods are used if high precision single piece machining of off-axis parabolic mirrors is required. I.e. must rely on sophisticated numerical control optical machining equipment. At present, the cutting technology is generally adopted, a large rotationally symmetrical female paraboloidal mirror is firstly manufactured, and then a required part is cut by a cutting tool. This method is only applicable to mirrors with smaller aperture and less off-axis.
The off-axis parabolic reflector mainly has the following indexes: clear aperture, off-axis amount (or off-axis angle), primary parabolic focal length and mirror surface precision. The mirror surface precision requirement is represented by wavelength, and the high one is divided into root mean square error (RMS) and peak-to-valley error (P-V); the lower ones are indicated by the diameter of the circle of confusion of the star point image.
The inertial confinement nuclear fusion engineering needs to converge multiple laser beams on a target pellet, and in order to properly distribute the multiple laser beams on the same horizontal plane, each path of light does not interfere with each other, off-axis paraboloids with different focal lengths and off-axis amounts need to be combined. In the current principle experiment stage, the focal length of the off-axis paraboloid reaches 30m grade, the off-axis amount reaches 15m grade, and with the development of the inertial confinement nuclear fusion engineering, the off-axis paraboloid with larger focal length and off-axis amount can be further required.
The patent numbers are: ZL 031131119.0's invention patent discloses a method for processing off-axis parabolic reflector, if use this method to process long focal length and lead to interfering the detection light path overlength when the off-axis parabolic mirror of large off-axis amount, the air current disturbance leads to the measuring accuracy to reduce; the large off-axis amount causes the resolution of the CCD to the fringes during interference detection to be reduced, and the reliability of the test is seriously influenced. For example, an off-axis paraboloid with a focal length of 30m and an off-axis amount of 15m, the field in the thermostatic chamber required for interference inspection is at least 20m (long) x 10m (wide), and the length of the optical path for interference inspection exceeds 60m, and airflow disturbance has great influence on the surface shape error of the paraboloid.
Therefore, the high-precision processing of the long-focus large-off-axis-amount off-axis paraboloid is limited by high-precision detection, and the prior art cannot meet the requirement.
Disclosure of Invention
The invention aims to solve the technical problem of poor processing precision caused by low detection precision of a long-focus large-off-axis-amount off-axis paraboloid, and adopts the following technical scheme:
an interference detection optical path of a long-focus large-off-axis-quantity off-axis paraboloid is sequentially arranged along the propagation direction of light waves emitted by an interferometer: the interferometer comprises a divergent lens, a standard spherical reflector and a standard plane reflector, wherein the divergent lens modulates light waves emitted by the interferometer into divergent spherical waves, the divergent spherical waves are reflected by the standard spherical reflector to be incident to a measured long-focus large-off-axis-quantity off-axis paraboloid, the light waves reflected by the measured long-focus large-off-axis-quantity off-axis paraboloid are plane waves, and the plane waves are perpendicularly incident to the standard plane reflector and then return to the original path; the standard spherical reflector and the long-focus large-off-axis-amount off-axis paraboloid to be measured form an off-axis two-mirror system, and the virtual focus of the divergent lens is superposed with the image point of the off-axis two-mirror system. By combining the theory of three-level aberration, the fine parallel beams of the central field can be solved on the premise that astigmatism, spherical aberration and coma aberration are eliminated at the focus F: the system comprises a standard spherical reflector radius R2, a distance d1 from the geometric center of an off-axis paraboloid to the geometric center of a standard spherical reflector, a distance d2 from the center of the standard spherical reflector to the image point of the off-axis two-mirror system, an included angle theta 1 between the normal line of the standard plane reflector and the normal line of the geometric center of the off-axis paraboloid reflector, and an included angle theta 2 between a principal ray emitted from the geometric center of the standard spherical reflector to the off-axis paraboloid reflector and the normal line of the geometric center of the standard spherical reflector. Therefore, when the focal length f and the off-axis quantity H of the off-axis parabolic mirror are given, the initial structure of the off-axis two-mirror system can be solved to obtain the initial structure of the light path, and a professional optical design software is input for optimization to obtain the off-axis two-mirror system inspection scheme of the off-axis parabolic mirror. Because the divergent lens is selected in the scheme, and the virtual focus of the divergent lens is superposed with the image point of the off-axis two-mirror system, the optical path length is effectively shortened; the length of the light path is further shortened and the width of the light path is compressed by matching with a standard spherical reflector and a standard plane reflector; in addition, the technical scheme effectively utilizes the pixel of the CCD and increases the detection resolution of the detected workpiece.
An interference detection method of a long-focus large-off-axis-amount off-axis paraboloid using the interference detection light path.
A method for detecting a long-focus large-off-axis-amount off-axis paraboloid comprises the following steps: measuring by using a three-coordinate measuring machine, and solving surface error distribution according to a parameter equation of the long-focus large-off-axis-quantity off-axis paraboloid; in the polishing stage: the interference detection method is used for measurement, and the surface error distribution is analyzed from the interference fringes. In the grinding stage, because the surface reflectivity is low, interference detection is not suitable, surface error distribution can be obtained by using three-coordinate measurement, important geometric parameters of curvature radius and off-axis quantity can also be measured, and the out-of-tolerance of other important geometric parameters in the process of processing the paraboloid can be effectively prevented.
An interference detection method of a long-focus large-off-axis-amount off-axis paraboloid using the interference detection light path.
A method for detecting a long-focus large-off-axis-amount off-axis paraboloid comprises the following steps: measuring by using a three-coordinate measuring machine, and solving surface error distribution according to a parameter equation of the long-focus large-off-axis-quantity off-axis paraboloid; in the polishing stage: the interference detection method is used for measurement, and the surface error distribution is analyzed from the interference fringes. In the grinding stage, because the surface reflectivity is low, interference detection is not suitable, surface error distribution can be obtained by using three-coordinate measurement, important geometric parameters of curvature radius and off-axis quantity can also be measured, and the out-of-tolerance of other important geometric parameters in the process of processing the paraboloid can be effectively prevented.
Based on the detection method of the long-focus large off-axis amount off-axis paraboloid, in the rough polishing stage of polishing: carrying out shadow inspection by using a knife edge instrument; the collimator tube provides a large-aperture parallel light beam, the parallel light beam is parallel to the optical axis of the primary paraboloid of the measured long-focus large-off-axis-quantity off-axis paraboloid, the parallel light beam is converged at the focus F of the paraboloid after being reflected by the measured long-focus large-off-axis-quantity off-axis paraboloid, and the convergence wavefront of the measured long-focus large-off-axis-quantity off-axis paraboloid is subjected to shadow inspection by using a two-dimensional knife edge on the focal plane at the focus F. In the rough polishing stage at the initial stage of polishing, because the surface error is large, interference fringes present segment bands or are very dense at the position where the local error is changed sharply, so that CCD is difficult to distinguish, and therefore, if the local error is large in the rough polishing stage, the interference detection is difficult to detect the error distribution at the position where the error is large; the knife edge instrument performs shadow inspection, error height distribution is obtained by observing light and shade distribution of light on a measured surface, the phenomenon is visual, the operation is convenient and fast, and the processing of the whole surface can be guided; after rough polishing is finished, the interference detection method is used for measurement, so that the detection precision can be further improved, and surface error distribution can be obtained quantitatively.
Based on the detection method, a method for manufacturing the long-focus large-off-axis-amount off-axis paraboloid is also provided, and the curvature radius of the optimal starting spherical surface is calculated according to the technical parameters of the long-focus large-off-axis-amount off-axis paraboloid; manufacturing a mirror blank, and making an optimal starting spherical surface; in the grinding stage, grinding the optimal starting spherical surface into the long-focus large-off-axis-amount off-axis paraboloid according to surface error distribution obtained by three-coordinate test; in the polishing stage, the interference detection method of the long-focus large-off-axis-amount off-axis paraboloid is used for obtaining surface error distribution. After several polishing and interference detection cycles, the surface error converges to the desired value.
Preferably, the method for manufacturing the long-focus off-axis paraboloid with large off-axis amount comprises the following steps of: carrying out shadow inspection by using a knife edge instrument; the collimator tube provides a large-aperture parallel light beam, the parallel light beam is parallel to the optical axis of the primary paraboloid of the measured long-focus large-off-axis-quantity off-axis paraboloid, the parallel light beam is converged at the focus F of the paraboloid after being reflected by the measured long-focus large-off-axis-quantity off-axis paraboloid, and the convergence wavefront of the measured long-focus large-off-axis-quantity off-axis paraboloid is subjected to shadow inspection by using a two-dimensional knife edge on the focal plane at the focus F.
The specific process steps are as follows:
solving the curvature radius of the optimal initial spherical surface of the long-focus large-off-axis-amount off-axis paraboloid according to the technical parameters;
step two, processing a standard spherical reflector for inspection; manufacturing a mirror blank, and making an optimal starting spherical surface; processing a square metal mirror frame, and putting a mirror blank into the square metal mirror frame and sealing the gap; marking the middle of one side of the mirror frame and the corresponding position of the mirror blank respectively;
measuring and acquiring surface error distribution of the long-focus large-off-axis-quantity off-axis paraboloid by using a three-coordinate measuring machine, and marking a high-low band on the mirror surface;
grinding the long-focus large-off-axis-amount off-axis paraboloid by using a grinding process;
step five, repeating detection and grinding until the surface error PV value of the long-focus large-off-axis-amount off-axis paraboloid is smaller than the measurement precision of the three-coordinate measuring machine;
step six, in the rough polishing stage of polishing, carrying out shadow inspection by using a knife edge instrument; erecting a square mirror frame, enabling the measured long-focus large-off-axis-amount off-axis paraboloid to face to a collimator for inspection, adjusting a detection light path, observing the distribution of shadow maps on the measured long-focus large-off-axis-amount off-axis paraboloid, comparing the distribution of the shadow maps with a three-coordinate measurement result, and planning a processing area according to the distribution of the shadow maps;
and step seven, acquiring surface error distribution by using an interference detection method of the long-focus large-off-axis-amount off-axis paraboloid. The shadow map distribution is compared with the three-coordinate measurement result, so that the adjustment of a shadow detection light path of the knife edge instrument can be assisted, the accuracy of the shadow detection result of the knife edge instrument can be proved, and the corresponding height conditions of a bright area and a dark area can be conveniently judged.
Drawings
FIG. 1: an off-axis parabolic reflector frame schematic;
FIG. 2: the framing schematic diagram of the off-axis paraboloid closest to the spherical reflector;
FIG. 3: a knife edge shadow inspection light path diagram of the off-axis parabolic reflector;
FIG. 4: a schematic diagram of an interference inspection light path of the off-axis parabolic reflector;
FIG. 5: a second schematic diagram of an interference inspection light path of the off-axis parabolic reflector;
FIG. 6: a long-focus large-off-axis-quantity off-axis paraboloid interference inspection light path diagram;
FIG. 7: the off-axis two-mirror system is used for checking an off-axis parabolic mirror light path diagram with the focal length f =18m and the off-axis quantity H =9 m;
FIG. 8: the off-axis two-mirror system is used for detecting a distribution diagram of residual wave difference of an off-axis paraboloid with the focal length f =18m and the off-axis quantity H =9 m; wherein: 1-off-axis parabolic reflector, 2-flat ruler, 3-collimator, 4-two-dimensional knife edge, 5-laser interferometer, 6-standard spherical reflector, 7-standard plane reflector, 8-divergent lens, 9-off-axis parabolic reflector geometric center normal and 10-standard spherical reflector geometric center normal; the method comprises the following steps of H-off-axis amount of an off-axis paraboloid, F-focal length of the off-axis paraboloid, focal position of the F-off-axis paraboloid, d 1-distance from a geometric center of the off-axis paraboloid to a geometric center of a standard spherical surface, theta 1-included angle between a normal line of the standard plane reflector and a normal line of the geometric center of the off-axis paraboloid reflector, and theta 2-included angle between a principal ray emitted from the geometric center of the standard spherical surface reflector to the off-axis paraboloid reflector and the normal line of the geometric center of the.
Detailed Description
For a more clear explanation of the invention, reference is made to the following description, taken in conjunction with the accompanying drawings and examples:
the first embodiment is as follows:
taking an off-axis parabolic mirror with the aperture of D1= Φ 400mm, the thickness of 60mm, the back focal length of f =18m, and the off-axis amount of H =9m as an example, a detection optical path of a long-focus large-off-axis-amount off-axis parabolic mirror is, as shown in fig. 6, sequentially arranged along the propagation direction of a light wave emitted by an interferometer 5: the interferometer comprises a divergent lens 8, a standard spherical reflector 6 and a standard plane reflector 7, wherein the divergent lens modulates the light wave emitted by the interferometer into divergent spherical wave, the divergent spherical wave is reflected by the standard spherical reflector and is incident to a measured long-focus large-off-axis-amount off-axis paraboloid 1, the light wave reflected by the measured long-focus large-off-axis-amount off-axis paraboloid is a plane wave, and the plane wave vertically enters the standard plane reflector and returns to the original path;
the standard spherical reflector and the long-focus large-off-axis-amount off-axis paraboloid to be measured form an off-axis two-mirror system, and the virtual focus of the divergent lens is superposed with the image point of the off-axis two-mirror system.
A method for detecting a long-focus large-off-axis-amount off-axis paraboloid by using the optical path.
A method for detecting a long-focus large-off-axis-amount off-axis paraboloid comprises the following steps of: measuring by using a three-coordinate measuring machine, and solving surface error distribution according to a parameter equation of the long-focus large-off-axis-quantity off-axis paraboloid;
in the polishing stage: and performing interference detection by using the detection light path of the long-focus large-off-axis-amount off-axis paraboloid, and analyzing surface error distribution from the interference fringes.
In the rough polishing stage of polishing: carrying out shadow inspection by using a knife edge instrument; the collimator 3 provides a large-aperture parallel light beam which is parallel to the optical axis of the primary parabolic reflector 1 of the measured long-focus large-off-axis-quantity off-axis paraboloid, the parallel light beam is converged at the focus F of the paraboloid after being reflected by the measured long-focus large-off-axis-quantity off-axis paraboloid, and the convergence wavefront of the measured long-focus large-off-axis-quantity off-axis paraboloid is subjected to shadow inspection by using a two-dimensional knife edge on the focal plane at the focus F.
Example two:
with reference to fig. 1, taking an example of processing an off-axis parabolic mirror with an aperture of D1= Φ 400mm, a thickness of 60mm, a back focal length of f =18m, and an off-axis amount of H =9m, a method for manufacturing a long-focus large-off-axis amount off-axis parabolic mirror:
the method comprises the following steps: an off-axis two-mirror inspection system is designed according to parameters of an off-axis parabolic mirror, an optical path diagram obtained by optimization design of a ZEMAX program is shown in FIG. 7, and as can be seen from the diagram, a deflection angle theta 1=14.9575 degrees, a deflection angle theta 2= -10.334 degrees, a radius of a standard spherical mirror is R2=21650 +/-300 mm, an interval between the two mirrors is D1=2500mm, a distance D2=7500mm from the center of the standard spherical mirror to an image point of a two-mirror system is about D2= Φ 385mm, an image F/# of the system is F/19.5 (equivalent to a divergent standard lens F/# of F/15), and an original off-axis F/# is F/45. The wavefront error of the system is shown in fig. 8, the wavefront residual error PV =0.11 λ, RMS =0.0273 λ (λ =0.6328 μm), that is, the residual error of the off-axis parabolic mirror can reach RMS =0.01365 λ (λ =0.6328 μm), and the inspection accuracy requirement of most off-axis parabolic mirrors can be met.
The off-axis two-mirror system is an optical system with an included angle between the chief ray of the central view field and the symmetry axis of the mirror surface. Under the off-axis condition, the central field of view has large astigmatism, so that one of the two mirrors has to be double curvature to compensate the astigmatism of the central field of view, and the off-axis parabolic mirror is a double-curvature mirror, so that the astigmatism, spherical aberration and coma aberration of thin parallel beams (zero-field-of-view parallel light incidence) of the central field of view are eliminated at a focus F by combining a standard spherical mirror and a three-level aberration theory, and the initial structure of the detection system can be solved.
Step two: machining an initial spherical surface of a standard spherical mirror D2= Φ 385mm, R2=21650 ± 300mm and a long-focus, large-off-axis amount off-axis paraboloid (closest spherical surface D1= Φ 400mm, R1=33590 ± 300 mm);
step three: as shown in figure 1, a square aluminum frame is processed to ensure that the flatness of one side surface is good, the aluminum frame is in contact with a bottom supporting and adjusting frame after being erected in later-stage optical inspection, the circular aperture of the aluminum frame is slightly larger than the external circle size of an off-axis paraboloid, a small step is processed at the bottom for supporting a glass mirror blank, and the difference between the depth of the circular aperture of the aluminum frame and the thickness of the mirror blank of the off-axis paraboloid is about 10mm, so that a silicon rubber is used for bonding a mirror and a mirror frame and finding a reference in later-stage three-coordinate measurement. According to the external dimension of the off-axis parabolic reflector, the external dimension of the aluminum frame is 440mm multiplied by 60mm, the central round hole phi is 400mm with positive tolerance, the step height is 10mm, the width is 10mm, and thus the thickness direction of the framed mirror is 10mm higher than the plane of the aluminum frame 440mm multiplied by 440 mm;
step four: framing the initial spherical mirror of the processed off-axis parabolic reflector, sticking the excircle gap with medical adhesive tape, and then coating 703 silicon rubber on the adhesive tape to ensure that the medical adhesive tape is covered by the silicon rubber; the framed structure is shown in fig. 2.
Step five: measuring the mirror surface of the initial spherical reflector by using a three-coordinate measuring machine, fitting the surface deviation of the off-axis parabolic reflector according to parameters such as the focal length and the off-axis amount of the off-axis parabolic reflector, marking a high-low band on the mirror surface, polishing the mirror surface according to the high-low band, and repeating the step until the mirror surface error PV value of the off-axis parabolic reflector is less than 2 microns;
step six: establishing a knife edge shadow inspection light path according to the graph 3, providing a large-caliber parallel light beam by a collimator tube 3, enabling the parallel light beam to be parallel to a mother paraboloid optical axis of an off-axis paraboloid reflector 1, converging the parallel light beam at a focus F of an off-axis paraboloid after the parallel light beam is reflected by the off-axis paraboloid reflector, performing shadow inspection on the converging wavefront of the off-axis paraboloid reflector on a focal plane by using a two-dimensional knife edge 4, judging the height zone of a paraboloid mirror surface according to the brightness of a shadow cut by the knife edge, and polishing the height; in the figure, the projection of the flat ruler 2 on the off-axis parabolic reflector coincides with the symmetry axis of the aluminum frame, specifically, a cross line is drawn in the diameter direction of the off-axis parabolic reflector, eyes observe the focus of the off-axis parabolic reflector and adjust the flat ruler to enable the vertical line of the cross line to coincide with the projection of the flat ruler, and the vertical distance from the focus of the off-axis parabolic reflector to the flat ruler in the figure is the off-axis amount H of the off-axis parabolic reflector; grinding the mirror surface of the off-axis parabolic reflector according to a shadow map obtained by the two-dimensional knife edge, and detecting and grinding for multiple times to reach the detection limit of a knife edge instrument;
step seven: a self-alignment interference inspection light path is set up according to the graph 6, a standard mirror of the laser interferometer uses a transmitting lens, the virtual focus of the lens is superposed with the image point of an off-axis two-mirror system, so that divergent spherical waves emitted by the spherical laser interferometer are reflected by the standard spherical reflector and the off-axis parabolic reflector to form parallel light beams, the parallel light beams vertically enter the standard plane reflector and then return to the original path, and the self-alignment interference inspection of the long-focus and large-off-axis amount off-axis parabolic reflector is realized; judging whether the surface shape error of the off-axis paraboloid needs to be further polished according to the test result; and if the technical index requirements are met, stopping grinding.
Step eight: and (3) scribing lines at the outer circle with the minimum off-axis amount of the off-axis parabolic reflector according to the symmetry of the aluminum frame, taking the off-axis parabolic reflector out of the aluminum frame, and wiping and cleaning the mirror surface, the outer circle and the bottom to finish machining.
In contrast, the technical problems arising when using a detection scheme such as that of FIG. 4 or that of FIG. 5 in step seven are analyzed separately below. If the laser interferometer 5 is a plane laser interferometer with a large caliber, the interference inspection light path shown in figure 4 is adopted, the plane laser interferometer with the large caliber emits parallel laser beams, the parallel laser beams are reflected by the off-axis parabolic reflector and then converge at the focus of the off-axis parabolic reflector, a standard spherical reflector is arranged behind the focus of the off-axis parabolic reflector, and the sphere center of the spherical reflector is coincided with the focus of the off-axis parabolic reflector, so that the self-alignment interference inspection of the off-axis parabolic reflector can be realized. If the plane interferometer with a large caliber is not provided or the clear aperture of the off-axis parabolic reflector is larger than the caliber of the plane laser interferometer, the interference inspection of the off-axis parabolic reflector can be realized by utilizing the inspection light path shown in figure 5; the interferometer emits standard spherical waves, the sphere center of the spherical waves is superposed with the focus of the off-axis parabolic reflector, the spherical waves are reflected by the off-axis parabolic reflector to form parallel light beams, the parallel light beams are vertically incident to the standard plane reflector shown in the figure, and the parallel light beams enter the interferometer after returning from the original path, so that the self-alignment interference inspection of the off-axis parabolic reflector is realized. However, for the off-axis parabolic reflector with a focal length of 30m or more and an off-axis amount of 15m or more, if the interference inspection light path shown in fig. 4 or fig. 5 is close to 80m, it is critical that a room of 35m × 20m is required to construct such an inspection light path, and the temperature of the room needs to be controlled within a certain range, so that the requirement on the processing environment of the off-axis parabolic reflector is high in general; in addition, fig. 4 or fig. 5 for detecting the long-focus large-off-axis amount off-axis parabolic interference fringes can only be imaged in a very small area of the CCD, with the consequence that the whole CCD is not effectively utilized, and only a few pixels on the CCD image the interference fringes, which is equivalent to reducing the resolution of the interference fringes.
Due to the application of the technical scheme, the following technical effects are realized:
1. by utilizing the technical scheme, the axial and transverse space size requirements of the optical path can be effectively compressed and inspected, the axial compression ratio is about 2:1, the transverse compression ratio is about 5:1, and the requirement on the field area is greatly reduced in the processing process;
2. the image space F/# of a general long-focus large-off-axis-quantity off-axis paraboloid exceeds F/50, the image space F/# of a detection light path is increased by more than two times by using the technical scheme, namely is increased to about F/20, and the number of CCD pixels of more interferometers can be corresponded when a standard lens of zygo F/15 is used for self-alignment interference detection, so that the interference detection precision is improved;
3. by utilizing the technical scheme, the length of the optical path is shortened to one third of the original scheme during the self-alignment interference inspection, the adverse effect of air disturbance on the inspection result can be effectively restrained, the interference inspection precision is improved, and the guarantee is provided for processing the off-axis mirror meeting the technical requirements.
Claims (3)
1. A method for manufacturing a long-focus large-off-axis-amount off-axis paraboloid comprises the steps of calculating the curvature radius of an optimal starting spherical surface according to technical parameters of the long-focus large-off-axis-amount off-axis paraboloid; manufacturing a mirror blank, and making an optimal starting spherical surface; in the grinding stage, grinding the optimal starting spherical surface into the long-focus large-off-axis-amount off-axis paraboloid according to surface error distribution obtained by three-coordinate test; in the polishing stage, an interference detection method is used for obtaining surface error distribution, and the surface error is converged to an expected value through a plurality of polishing detection cycles; the method is characterized in that:
the interference detection method comprises the following steps that a divergence lens, a standard spherical reflector and a standard plane reflector are sequentially arranged along the propagation direction of light waves emitted by an interferometer, the divergence lens modulates the light waves emitted by the interferometer into divergent spherical waves, the divergent spherical waves are reflected by the standard spherical reflector and are incident to a measured long-focus large-off-axis-amount off-axis paraboloid, the light waves reflected by the measured long-focus large-off-axis-amount off-axis paraboloid are plane waves, and the plane waves vertically enter the standard plane reflector and then return to the original path; the standard spherical reflector and the long-focus large-off-axis-amount off-axis paraboloid to be measured form an off-axis two-mirror system, and the virtual focus of the divergent lens is superposed with the image point of the off-axis two-mirror system.
2. The method for manufacturing a tele off-axis parabolic surface according to claim 1, wherein the method comprises: in the rough polishing stage of polishing, carrying out shadow inspection by using a knife edge instrument; the collimator tube provides a large-aperture parallel light beam, the parallel light beam is parallel to the optical axis of a mother paraboloid of the measured long-focus large-off-axis-quantity off-axis paraboloid, the parallel light beam is converged at a focus F of the paraboloid after being reflected by the measured long-focus large-off-axis-quantity off-axis paraboloid, and the convergence wavefront of the measured long-focus large-off-axis-quantity off-axis paraboloid is subjected to shadow inspection by using a two-dimensional knife edge on a focal plane at the focus F.
3. The method for manufacturing a tele off-axis parabolic surface according to claim 2, wherein the method comprises: solving the curvature radius of the optimal initial spherical surface of the long-focus large-off-axis-amount off-axis paraboloid according to the technical parameters;
step two, processing a standard spherical reflector for inspection; manufacturing a mirror blank, and making an optimal starting spherical surface; processing a square metal mirror frame, and putting a mirror blank into the square metal mirror frame and sealing the gap; marking the middle of one side of the mirror frame and the corresponding position of the mirror blank respectively;
measuring and acquiring surface error distribution of the long-focus large-off-axis-quantity off-axis paraboloid by using a three-coordinate measuring machine, and marking a high-low band on the mirror surface;
grinding the long-focus large-off-axis-amount off-axis paraboloid by using a grinding process;
step five, repeating detection and grinding until the surface error PV value of the long-focus large-off-axis-amount off-axis paraboloid is smaller than the measurement precision of the three-coordinate measuring machine;
step six, in the rough polishing stage of polishing, carrying out shadow inspection by using a knife edge instrument; erecting a mirror frame, enabling the measured long-focus large-off-axis-amount off-axis paraboloid to face to a collimator for inspection, adjusting a detection light path, observing the distribution of shadow maps on the measured long-focus large-off-axis-amount off-axis paraboloid, comparing the distribution of the shadow maps with a three-coordinate measurement result, and planning a processing area according to the distribution of the shadow maps;
and seventhly, acquiring surface error distribution by using the interference detection method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811056441.8A CN109163663B (en) | 2018-09-11 | 2018-09-11 | Manufacturing method of long-focus large-off-axis-amount off-axis paraboloid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811056441.8A CN109163663B (en) | 2018-09-11 | 2018-09-11 | Manufacturing method of long-focus large-off-axis-amount off-axis paraboloid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109163663A CN109163663A (en) | 2019-01-08 |
| CN109163663B true CN109163663B (en) | 2020-09-11 |
Family
ID=64894859
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811056441.8A Active CN109163663B (en) | 2018-09-11 | 2018-09-11 | Manufacturing method of long-focus large-off-axis-amount off-axis paraboloid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109163663B (en) |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85106896A (en) * | 1985-09-18 | 1987-04-01 | 华北光电技术研究所 | Paraboloid processing devices |
| US4859861A (en) * | 1988-05-16 | 1989-08-22 | Becton, Dickinson And Company | Measuring curvature of transparent or translucent material |
| CN1337047A (en) * | 1999-01-21 | 2002-02-20 | X射线光学系统公司 | Curved optical device and method of fabrication |
| CN1444058A (en) * | 2003-04-03 | 2003-09-24 | 苏州大学 | Production method of off-axis paraboloid mirror |
| CN101858735A (en) * | 2010-05-19 | 2010-10-13 | 中国科学院光电技术研究所 | Large-caliber off-axis non-spherical measuring and calibration system |
| CN102049530A (en) * | 2010-11-03 | 2011-05-11 | 天津大学 | Precision turning processing method for off-axis aspheric mirror with large off-axis |
| CN102686972A (en) * | 2009-09-18 | 2012-09-19 | 卡尔蔡司Smt有限责任公司 | Method of measuring a shape of an optical surface and interferometric measuring device |
| CN105115444A (en) * | 2015-09-08 | 2015-12-02 | 上海现代先进超精密制造中心有限公司 | Detection device and detection method of off-axis parabolic mirror surface shape precision |
| CN105511001A (en) * | 2016-01-19 | 2016-04-20 | 中国科学院上海光学精密机械研究所 | Method for manufacturing large-aperture off-axis parabolic mirror |
| CN107984303A (en) * | 2017-11-07 | 2018-05-04 | 中国科学院上海光学精密机械研究所 | The processing method of uniform thickness off-axis aspheric surface speculum |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5356757B2 (en) * | 2008-09-05 | 2013-12-04 | Ｈｏｙａ株式会社 | Aspherical lens shape evaluation method |
| CN103969787B (en) * | 2014-05-22 | 2016-08-17 | 北京空间机电研究所 | A kind of first assembling and positioning method of off-axis four anti-camera lenses |
-
2018
- 2018-09-11 CN CN201811056441.8A patent/CN109163663B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85106896A (en) * | 1985-09-18 | 1987-04-01 | 华北光电技术研究所 | Paraboloid processing devices |
| US4859861A (en) * | 1988-05-16 | 1989-08-22 | Becton, Dickinson And Company | Measuring curvature of transparent or translucent material |
| CN1337047A (en) * | 1999-01-21 | 2002-02-20 | X射线光学系统公司 | Curved optical device and method of fabrication |
| CN1444058A (en) * | 2003-04-03 | 2003-09-24 | 苏州大学 | Production method of off-axis paraboloid mirror |
| CN102686972A (en) * | 2009-09-18 | 2012-09-19 | 卡尔蔡司Smt有限责任公司 | Method of measuring a shape of an optical surface and interferometric measuring device |
| CN101858735A (en) * | 2010-05-19 | 2010-10-13 | 中国科学院光电技术研究所 | Large-caliber off-axis non-spherical measuring and calibration system |
| CN102049530A (en) * | 2010-11-03 | 2011-05-11 | 天津大学 | Precision turning processing method for off-axis aspheric mirror with large off-axis |
| CN105115444A (en) * | 2015-09-08 | 2015-12-02 | 上海现代先进超精密制造中心有限公司 | Detection device and detection method of off-axis parabolic mirror surface shape precision |
| CN105511001A (en) * | 2016-01-19 | 2016-04-20 | 中国科学院上海光学精密机械研究所 | Method for manufacturing large-aperture off-axis parabolic mirror |
| CN107984303A (en) * | 2017-11-07 | 2018-05-04 | 中国科学院上海光学精密机械研究所 | The processing method of uniform thickness off-axis aspheric surface speculum |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109163663A (en) | 2019-01-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107796329B (en) | A kind of convex aspheric surface reflecting mirror surface shape detection device and detection method | |
| CN106735864B (en) | The coaxial vibration mirror scanning laser processing and device detected in real time | |
| CN101858735B (en) | Large-caliber off-axis non-spherical measuring and calibration system | |
| CN107782254A (en) | A kind of mixed compensating mode sub-aperture stitching surface testing method | |
| CN112926192B (en) | Polarization aberration analysis method for off-axis free-form surface optical system | |
| CN106225712A (en) | A kind of off-axis three anti-aspheric optical systems benchmaring and processing method altogether | |
| CN104374334A (en) | Free-form surface morphology three-dimensional measurement method and device | |
| CN115166932B (en) | Optical axis adjusting method of large-caliber long-focus off-axis optical system | |
| CN113739719B (en) | Surface shape detection system and method of high-precision Schmidt correction plate | |
| CN115290006A (en) | System and method for alignment of optical axis and detection of surface curvature of reflection light path | |
| CN112902875B (en) | Aspheric reflector curvature radius detection device and method | |
| CN109163682B (en) | Detection device and method for long-focus large-off-axis-amount off-axis paraboloid | |
| CN107131846A (en) | A kind of optical system for the convex oblate spheroid detection of super large caliber | |
| CN106767471B (en) | Optical interval measuring system and method in aspheric surface detection light path | |
| CN109163663B (en) | Manufacturing method of long-focus large-off-axis-amount off-axis paraboloid | |
| CN110986836B (en) | High-precision roughness measuring device based on annular core optical fiber | |
| CN208736353U (en) | A kind of detection focal length measures greatly the optical system of off axis paraboloidal mirror off axis | |
| CN106225713A (en) | A kind of off-axis three anti-aspheric optical systems benchmaring and processing method altogether | |
| CN113295386B (en) | Optical lens piece detection system and detection method | |
| CN115164775A (en) | Large-caliber convex aspheric reflector surface shape detection device and detection method thereof | |
| CN105629430B (en) | 360 degree of total reflection prisms and its aligning method | |
| US11333487B2 (en) | Common path mode fiber tip diffraction interferometer for wavefront measurement | |
| CN110440715B (en) | Error compensation method of photoelectric autocollimator under long-distance working condition | |
| CN113703124B (en) | Method for correcting coaxiality of biconcave off-axis system | |
| Wang et al. | Laser confocal auto-collimation decentration measurement for spherical lens |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |