CN102288132A

CN102288132A - Method for measuring vertex curvature radius deviation of aspheric surface by using laser tracking instrument

Info

Publication number: CN102288132A
Application number: CN2011101281776A
Authority: CN
Inventors: 李锐刚; 王孝坤; 郑立功; 张学军
Original assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Current assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Priority date: 2011-05-18
Filing date: 2011-05-18
Publication date: 2011-12-21
Anticipated expiration: 2031-05-18
Also published as: CN102288132B

Abstract

The invention discloses a method for measuring a vertex curvature radius deviation of an aspheric surface by using a laser tracking instrument, relating to methods for measuring the vertex curvature radius deviation of aspheric surfaces in compensation tests, which solves the problems of low accuracy, poor stability and fussy measuring process in the traditional measuring of a curvature radius of the aspheric surface. The method for measuring the vertex curvature radius deviation of the aspheric surface by using the laser tracking instrument comprises the following steps: enabling a compensator, an interferometer and an aspheric surface to be measured to be coaxial; obtaining optical axis position data of the compensator by using the laser tracking instrument; obtaining spatial position data of a rear vertex of the compensator according to the optical axis position data and mechanical design parameters of the compensator; measuring basic surface data of the aspheric surface to be measured by using the laser tracking instrument and then obtaining spatial position data of a vertex of the aspheric surface to be measured according to the obtained basic surface data, the mechanical design parameters and design parameters of the aspheric surface to be measured; and measuring an optical interval between the aspheric surface to be measured and the compensator by using the laser tracking instrument, i.e. the vertex curvature radius deviation of the aspheric surface to be measured. The method disclosed by the invention has the advantages of short measuring time, high accuracy and good universality.

Description

Adopt laser tracker to measure the method for aspheric surface vertex curvature radius deviation

Technical field

The present invention relates to the measuring method of aspheric surface vertex curvature radius deviation in a kind of compensation tests.

Background technology

For sphere, the method of control radius-of-curvature is many, can utilize spherometer to detect radius-of-curvature in the fine grinding stage, the polishing stage can see that aperture controls radius-of-curvature and local error by testplate, also has interferometric method directly to utilize the guide rail that has high precision grating chi to survey distance between the workpiece centre of sphere and the summit etc. in addition.And will difficulty for the control of aspheric vertex curvature radius many, because the interferometric method during so all different with the vertex curvature radius similar spheres of the radius-of-curvature of each point are measured except that the summit concerning aspheric surface can't be applied to the measurement of aspheric surface vertex curvature radius, though spherometer method and template method can be compared with local radius of curvature by the endless belt measurement and be measured indirectly, precision and stability are not high; Have in addition and mention the method for utilizing measuring staff to detect vertex curvature radius in the document, this method benchmark is changed the more precision and very high to the measuring staff requirement on machining accuracy that influences, and has that will to process different measuring staffs for different aspheric surfaces also very loaded down with trivial details again.

Summary of the invention

The present invention is low, the poor stability of measuring accuracy of the existing aspheric curvature radius of solution, and the loaded down with trivial details problem of measuring process, and a kind of method that adopts laser tracker to measure aspheric surface vertex curvature radius deviation is provided.

The method that adopts laser tracker to measure aspheric surface vertex curvature radius deviation is realized by following steps:

Step 1, adjustment compensator, interferometer and aspheric relative position to be detected make compensator, interferometer and aspheric surface to be detected coaxial;

The reference field of step 2, employing laser tracker measuring process one described compensator, the optical axis position data of acquisition compensator;

Step 3, the optical axis position data that obtain according to step 2 and the Machine Design parameter of compensator obtain the spatial position data on summit behind the compensator;

Step 4, employing laser tracker are measured aspheric reference field data to be detected, according to the reference field data, Machine Design parameter and the aspheric design parameter to be detected that obtain, obtain the spatial position data on aspheric surface to be measured summit;

The spatial position data on summit and the spatial position data on aspheric surface to be measured summit behind step 5, the compensator that obtains according to step 3 and step 4, the employing laser tracker detects the optical interval between aspheric surface to be detected and the compensator, and the deviation of described optical interval is the deviation of aspheric surface vertex curvature radius to be detected.

Principle of work of the present invention: the device that the method for employing laser tracker check aspheric surface vertex curvature radius deviation of the present invention need be used comprises laser tracker, aspheric surface to be measured, high precision aspheric surface compensator and computing machine etc.Can know the optical interval of equal value and control aspheric surface vertex curvature radius of control aspheric surface compensator by ray tracing and TOLERANCE ANALYSIS to the aspheric surface summit, so the present invention at first utilizes laser tracker to measure the spatial positional information that the pre-designed mechanical references that is closely related with optical axis on the high-accuracy compensation device is determined summit behind the optical surface of optical axis and compensator, utilize laser tracker to measure reference field pre-designed on the aspheric surface to be measured then, according to mathematical model, with software construction aspheric summit spatial positional information and resolve the accurate measured value of optical interval, thereby make aspheric vertex curvature radius precisely controlled.The key point of this invention is that not only measuring process implements, and the more important thing is the system design of the measuring basis that is applicable to laser tracker that compensator and aspheric surface are carried out, and suitable measuring basis is extremely important to the assurance of whole measuring accuracy.Method repeatable accuracy of mentioning in this invention and absolute precision are all very high, this is verified in the actual measurement process, and the stronger actual effect that has shown this method of superior optical property that aspheric surface is packed into and shown after the optical system in a plurality of case histories.

Beneficial effect of the present invention: the present invention adopts laser tracker control aspheric surface vertex curvature radius, Measuring Time is short, precision is high, versatility is good, and the present invention can be applicable in the non-spherical reflector polishing process or the accurate control of final inspection stage vertex curvature radius deviation.

Description of drawings

Fig. 1 is the detection synoptic diagram that employing laser tracker of the present invention is measured the method for aspheric surface vertex curvature radius deviation.

Among the figure: 1, interferometer, 2, compensator, 3, laser tracker, 4, aspheric surface to be detected.

Embodiment

Embodiment one, in conjunction with Fig. 1 present embodiment is described, adopts laser tracker to measure the method for aspheric surface vertex curvature radius deviation, this method is realized by following steps:

The relative position of step 1, adjustment compensator 2, interferometer 1 and aspheric surface to be detected 4 makes compensator 2, interferometer 1 and aspheric surface to be detected 4 coaxial;

The reference field of step 2, employing laser tracker 1 measuring process one described compensator 2, the optical axis position data of acquisition compensator 2;

Step 3, the optical axis position data that obtain according to step 2 and the Machine Design parameter of compensator 2 obtain the spatial position data on summits, compensator 2 back;

Step 4, employing laser tracker 3 are measured the reference field data of aspheric surface 4 to be detected, according to the design parameter of the reference field data, Machine Design parameter and the aspheric surface to be detected 4 that obtain, obtain the spatial position data on aspheric surface to be measured 4 summits;

The spatial position data on step 5, the summits, compensator 2 back that obtain according to step 3 and step 4 and the spatial position data on aspheric surface to be measured 4 summits, the optical interval that adopts laser tracker 3 to detect between aspheric surface 4 to be detected and the compensator 2, the deviation of described optical interval is the deviation of aspheric surface 4 vertex curvature radius to be detected.

The Machine Design parameter of the compensator 2 described in the present embodiment comprises flatness, cylinder degree, verticality and the mechanical dimension etc. of compensator; The design parameter of described aspheric surface to be detected 4 comprises optical design parameters such as quadric surface coefficient, vertex curvature radius, high-order term coefficient and component profile size etc.

Embodiment two, present embodiment are the embodiment that embodiment one described employing laser tracker is measured the method for aspheric surface vertex curvature radius deviation:

The directional light or the sphere optical registration of a, adjustment compensator 2 and interferometer 1 outgoing, adjust both relative positions of aspheric surface 4 element under tests to be detected and compensator 2 and interferometer 1 according to the principle of the primary aberration minimum of compensator 2, make whole compensator 2, interferometer 1 and aspheric surface to be detected 4 threes coaxial, this generally wants repeated multiple times, finally could adjust and finish; 2 designs of the compensator that has have a little field angle, and then can suitably relaxing collimation according to the field angle size, to require described primary aberration mainly be both direction astigmatism, both direction coma and out of focus.

All mechanical reference surface can be arranged when b, compensator 2 designs, these reference fields are associated with the optical axis information of compensator, therefore after finishing interferometer, compensator, aspherics to be checked adjustment, we utilize the reference field on laser tracker 3 measuring compensators, and according to reference field information calculations emergent shaft position, precision plain shaft precision general and the final assembling of compensator is suitable, and overall accuracy is approximately less than 5 rads.According to the optical axis data, we just can be compensated the spatial positional information on summit, device 2 back by the Machine Design parameter of compensator simultaneously;

Also be useful on the reference field that detects and assemble on c, the aspheric surface to be detected 4, the reference field information that we utilize laser tracker 3 to measure on the aspheric surface 4 to be detected, measurement data and Machine Design parameter and aspheric surface design parameter according to reference field can draw the spatial positional information on aspheric surface summit by structure;

The spatial positional information on summit and the spatial positional information on aspheric surface summit utilize laser tracker 3 subsidiary softwares just can calculate the optical interval of aspheric surface interference detection to be checked behind d, the compensator that obtains according to b and c;

E, repeating step a take multiple measurements to d, and carry out precision analysis.According in the past we in the number of actual measurements of a plurality of engineering projects according to one's analysis, the final optical interval of measuring of this method, that is: vertex curvature radius, relative deviation generally is better than 5/10000ths, some situation even can reach ten thousand/.

Claims

1. adopt laser tracker to measure the method for aspheric surface vertex curvature radius deviation, it is characterized in that this method is realized by following steps:

The relative position of step 1, adjustment compensator (2), interferometer (1) and aspheric surface to be detected (4) makes compensator (2), interferometer (1) and aspheric surface to be detected (4) coaxial;

The reference field of step 2, employing laser tracker (3) measuring process one described compensator (2), the optical axis position data of acquisition compensator (2);

Step 3, the optical axis position data that obtain according to step 2 and the Machine Design parameter of compensator (2) obtain the spatial position data on summit, compensator (2) back;

Step 4, employing laser tracker (3) are measured the reference field data of aspheric surface to be detected (4), according to the design parameter of the reference field data, Machine Design parameter and the aspheric surface to be detected (4) that obtain, obtain the spatial position data on aspheric surface to be measured (4) summit;

The spatial position data on step 5, the summit, compensator (2) back that obtains according to step 3 and step 4 and the spatial position data on aspheric surface to be measured (4) summit, employing laser tracker (3) detects the optical interval between aspheric surface to be detected (4) and the compensator (2), and the deviation of described optical interval is the deviation of aspheric surface to be detected (4) vertex curvature radius.

2. employing laser tracker according to claim 1 is measured the method for aspheric surface vertex curvature radius deviation, it is characterized in that the Machine Design parameter of compensator (2) comprises the flatness of compensator, cylinder degree, verticality and mechanical dimension.

3. employing laser tracker according to claim 1 is measured the method for aspheric surface vertex curvature radius deviation, it is characterized in that the design parameter of described aspheric surface to be detected (4) comprises optical design parameter and component profile sizes such as quadric surface coefficient, vertex curvature radius, high-order term coefficient.