SU1315799A1 - Device for measuring linear displacements - Google Patents

Abstract

The invention relates to a measurement technique and can be used in optical instrumentation dp defining the curvature of the surface of optical components. The aim of the invention is to measure the device also the radius of curvature of the optical surfaces. The radiation source 1, such as a laser, using telescopes VI VI with co

Description

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of the system 2 and the splitter 5 are directed onto the cortex of the object 16, mounted on the support platform 7 of the table 6, which can be moved in a plane perpendicular to the optical axis of the interferometer with the help of the displacement mechanism 8. The radiation reflected from the monitored surface is guided by an optical projection system 9 into a two-beam interferometer 13, which, when projected, is projected into the register plane optically coupled to the reference platform.

The invention relates to a measurement technique and can be used in optical instrumentation to determine the curvature of the surface of optical components.

The purpose of the invention is the measurement of the radius of curvature of the monitored optical surface due to the lateral shear of the beams in the interferometer.

The drawing shows a diagram of the proposed device.

The device contains a radiation source 1, for example a laser, a telescopic system 2 comprising two components 3 and 4, a first beam splitter 5, a table 6 with a support platform 7 and its movement mechanism 8, a projection optical system 9, a second beam splitter 10, two corner reflectors 11 and 12, which, together with the second beam splitter 10, form an interferometer 13, a slit diaphragm 14, a photodetector 15 and an electronic processing unit (not shown).

The device works as follows.

Pre-set and calibrate the device.

An object 16 with a controlled surface is placed on the support platform 7 of table 6.

The radiation from source 1, such as a laser, is directed through the telescopic system 2 and the beam splitter 5 to the object to be monitored 16. Reflected by the contact surface of the object

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The radio is equipped with a slit diaphragm 14. In a two-beam interferometer, the separated beams are laterally shifted by the value of d. When an object is moved in a plane perpendicular to the optical axis of the interferometer, the value of g records the movement of interference fringes in the recording plane. Registration is carried out using a photodetector 13 and a processing unit. By the number of recorded bands passing through the slit aperture 14, the surface radius is calculated. 1 il.

16, the radiation is intercepted by the projection optical system 9 and sent to the interferometer 13, where the radiation is shared by the second beamsplitter 10 in half, the separated beams are shifted relative to each other and the retroreflective corner reflectors 11 and 12.

The optical projection system 9 carries out the optical communication of the support platform 7 with the image plane in which the diaphragm 14 is placed. The radiation that has passed through the interferometer 13 forms two light spots on the slit diaphragm 14, displaced one relative to another along a straight, perpendicular aperture slit , the offset between which is

I d-p,

where d is the amount of lateral shift in the interferometer between the light-return beams; P is the linear increase in the optical interface system.

Interference fringes oriented perpendicularly to the direction of the lateral shift of the beams in the interferometer are observed in the field of the light beam transposition.

The reference pad 7 with a controlled surface (object 16) is moved perpendicular to the optical axis of the interferometer by an amount d, in this case the reflected beam undergoes a rotation through the angle ip equal to

fi - lf.

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2A / R, where R is the radius of curvature of the test surface, while the light beams in the registration plane are rotated

.fa 1 H and the drive to change times j9hI

carry the optical paths of these beams in the regression plane by

 2du g - p.

The change in the difference of the optical paths between the beams in the registration plane on the slit of the diaphragm leads to the displacement of the interference pattern. Observations of the interference pattern, determine the number of N interference fringes passing through the aperture slit.

From the number of interference fringes, the radius of curvature R of the test surface is calculated from the dependence

R

where is the wavelength of the radiation source;

D is the amount of movement of the support area with a controlled surface in a plane perpendicular to the optical axis.

Claims (1)

Invention Formula A device for measuring linear displacements, containing sequentially installed radiation sources, a telescopic system made of two components, and a light editor L. Kozoriz Order 2344/42 Compiled by N. Soloukhin Tehred M. Khodanych Circulation 677 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 94 the divider and reverse-mounted radiation from the object is an interferometer made in the form of a beam splitter and two corner reflectors, each of which is installed in the radiation flux from the corresponding light distributor, a diaphragm, a photodetector and an electronic processing unit that differs in that measuring the radius of curvature of the surface of the object under test, it is equipped with a projection-optical system located between the beam splitter and the interferometer, a table whose supporting platform is designed to accommodate the controlled surface of the object on it, and the mechanism for moving the reference platform in the direction perpendicular the optical axis of the interferometer, the diaphragm is made in the form of a slit, installed in the image registration plane and oriented so that the slit is perpendicular to the main section interferometer, the table is oriented so that its reference area is perpendicular to the optical axis of the interferometer and is located in the plane optically conjugated to the image recording plane, one of the telescopic system components is mounted for movement along the radiation direction, and one of the corner reflectors of the interferometer is offset with respect to the other in a plane perpendicular to the aperture of the diaphragm. Proofreader G. Reshetnik Subscription