SU201721A1 - INTERFEROMETER FOR THE QUALITY CONTROL OF CONCENTRED REFLECTIVE ROTATION SURFACES - Google Patents

Description

Known interferometers to control the quality of concave parabolic surfaces of rotation containing a reference branch and a working branch with a controlled part installed in it — and a compensator — do not allow to control the parabolic surfaces of convex lenses, to expand the range of controlled focal distances of the parabolic surfaces of lenses with a flat second surface or to exclude -the effect of their different focus and control lenses with aspheric second surface.

The interferometer according to the present invention differs from the known ones in that the compressor is installed on optical contact with the second surface of the test piece and is made in the form of a lens - with a flat surface and a refractive index equal to the refractive index of the test piece, and the sum of the thicknesses of the compensator and the piece under test is equal focal length of the reflecting surface. The difference is also the fact that the compensator can be made in the form of a flat-parallel plate of varying thickness composed of two lines or an immersion-filled cell.

The interferometer contains a light source 1, a pinhole 2, a lens 5, a collimator, a translucent mirror 4, a reference lens 5, a flat mirror 6, a secondary lens 7, a controlled lens 8, a lens 9 for the telescope and a diaphragm 10. In the working branch of the interferometer Optical contact with the second surface of the controlled lens 8 is provided with an additional lens 7, the flat surface of which coincides with the focal plane of the reflecting parabolic surface, and the refractive indices of the lenses 7 and S are the same. The thickness of the additional lens is equal to the difference between the focal length of the reflecting parabolic surface and the thickness of the controlled lens. On the nlosky surface of the additional lens 7 a mirror coating is applied, the size of which

virtually eliminates central vignetting. Such a device of the working branch of the interferometer makes it possible to carry out a course of rays, the lrn of which is convex;

parabolic mirror, focusing real rays falling in a parallel beam on a parabolic surface.

Obtaining interfacial bands is fundamentally impossible, therefore, the determination of very small log solutions is difficult.

The described interferometer is applicable to practically any form of the second surface of a Parabolic lens 8 (a, b, c, d). In case of a series of identical lenses, for example, convex-flat (c), an additional lens can be made of variable thickness, in the form of two movable wedges forming a flat-parallel plate, in order to expand the dialzone of the focal lengths of the reflecting larabolic surfaces or eliminate their different focus. . To control LI.NZ, the second surface of which is aspherical, ground or roughly processed, the latter can be installed in a cuvette with an immersion liquid, the refractive index of which is equal to the index of refractive index of the controllable lens (g).

The proposed method is fundamentally non-impermeable for controlling lenses whose thickness is greater than the focal length of the reflecting parabolic surface, and is most successful for controlling lenses that have a small focal distance of the reflecting parabolic surface.

The use of modern light sources, for example, optical cable-stayed generators, allows controlling lenses that have a practically unlimited relative aperture of a reflective larabolic surface. In this case, only a single flat can be installed in the working branch. Depending on the power of the applied light source, the parabolic surface either has a mirror coating, or works without it, to a polished reflecting surface.

Subject invention

1. An interferometer for controlling the quality of concave reflecting surfaces of rotation, containing a reference branch and a working branch with a controlled part installed in it and a compensator, characterized in that, in order to control larabolic surfaces of convex lenses, the compensator is mounted on an optical The second surface of the controlled part is made in the form of a lens with a flat surface and a refractive index equal to the refractive index of the controlled part, and the sum of the thicknesses of the compensator and control The detail is equal to the focal length of the reflective surface.

2. The interferometer. 1, characterized in that, in order to broaden the range of controlled focal lengths of larabolic surfaces of lenses with a flat second surface or to eliminate the effect of their different focus, the compensator is made in the form of two Klinov parallel parallel plate.

3. Interferometer. 1, characterized in that, with the aim of controlling the lenses with an aspheric second surface, the compass is made in the form of a cuvette with an immersion liquid.

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