SU1368623A1 - Interferometer for checking shape of concave optical aspherical surfaces - Google Patents

Abstract

The invention relates to a measurement technique and is intended for use in optical production in controlling the shape of concave optical aspherical surfaces, for example, the main mirrors of telescopes. The purpose of the invention is to simplify the design of the interferometer, increase. performance and accuracy of control. An interferometer to control the shape of concave optical aspherical surfaces contains successively located source 1 of monochromatic radiation, a telescopic system, consisting of lenses 2 and 3, a beam splitter 4, followed by a flat mirror 5 in one branch, and a lens 6 in the other 7 interference pattern. The lens 6 of the working branch is made in the form of flat-concave and two-convex lenses. Parallel paraxial rays are provided inside both lenses due to the fact that the posterior focus of a flat-concave lens is aligned with the front focus of that convex surface of the two-convex lens that faces the concave surface of the flat-concave lens. The flat surface of the flat-concave lens is used when adjusting the interferometer to correctly set the objective lens in an operating mode to create a reference wavefront. 1 il.

Description

The invention relates to a measurement technique and is intended for use in optical production in controlling the shape of concave optical aspherical surfaces, for example, the main mirrors of telescopes. The aim of the invention is to simplify the design of the interferometer, to increase the performance and accuracy of control due to the implementation of the objective of the working branch in the form of flat-concave and two-convex lenses, to simplify the installation process of the lens at a predetermined position when observing a continuous alignment interference pattern and degrading effect elements of the working branch on the results of the control.

The drawing shows a schematic diagram of the interferometer and the course of the rays in it.

The interferometer contains a monochromatic radiation source 1, a telescopic system for creating a parallel beam of rays consisting of lenses 2 and 3, a beam splitter 4 for dividing the radiation into two branches, a flat mirror 5 installed in one branch, an lens 6 installed in another working branch, and the interference pattern recorder 7.

The objective 6 of the working branch is made in the form of flat-concave and double-convex lenses installed so that the flat surface of the flat-curved lens faces the beam splitter 4. Inside these lenses, parallel paraxial rays are provided due to the fact that the back focus of the flat-bent lens is aligned with the front focus of that convex surface a two-convex lens, which faces the concave surface of a flat-concave lens.

The interferometer works as follows.

Rays of light emanating from source 1 of monochromatic radiation enter the telescopic system consisting of lenses 2 and 3, which

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reduces the beam divergence and increases its diameter. Next, the light beam passes through the beam splitter 4. falls on the reference surface 8

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falls on the reference surface of lens 6 and is divided into two beams. The light rays reflected from the surface 8 form a reference beam, which, after being reflected from the beam splitter 4, enters the recorder 7 of the interference pattern.

Rays of light passing through the lens 6, form a working beam. These rays fall on a controlled surface 9 along the normal meters to it. Reflected from it, the rays pass through the lens 6 in the opposite direction, are reflected from the beam splitter 4 and enter the recorder 7 of the interference pattern. The interference pattern arises as a result of the interaction of the reference and working beams. Mirror 5 is used to adjust the interferometer and to check the quality of the beam splitter 4. In the working mode, mirror 5 does not participate in the formation of the interference pattern.

Claims (1)

Invention Formula An interferometer for the contrl-shaped forms of concave optical aspherical surfaces containing successively installed monochromatic radiation source, a telescopic system and a beam splitter for dividing the radiation into two branches, a flat mirror mounted in one branch, an objective lens mounted in another branch, and an interference pattern recorder characterized by , 4TOi in order to simplify the design of the interferometer, increase productivity and accuracy of control, the lens is made in the form of a flat-concave and double convex lenses installed so that the flat surface of the flat-curved lens faces the beam splitter, and its back focus is aligned with the front focus of the convex surface of the double-convex lens that faces the concave surface of the flat-concave lens. VNII1SH Order 273/38 Circulation 680 Random polygons pr-tie, Uzhgorod, st. Project, 4 Subscription