US 4,904,084 A · Arrangement for testing complex concave reflecting surfaces for shape deviations

Abstract

An arrangement for testing a concave reflecting surface of a solid body, especially a relatively complex concave reflecting surface such as that of an X-ray barrel optics mirror element, for deviations of its actual shape from its ideal shape includes a laser source and a negative cylindrical lens interposed between the laser source and the reflecting surface to be tested. The lens optically modifies the laser beam in such a manner as to propagate between the lens and the reflecting surface substantially normal to the reflecting surface and to be reflected from the latter for propagation back to and through the lens toward the laser source as a return laser beam having a wave front indicative of the actual shape of the reflecting surface and any aberrations of the lens. The arrangement further includes an interferometer that forms an interference pattern between the original and return laser beams, and a circuitry for evaluating the interference pattern. The evaluating circuitry subtracts first and second reference signals respectively representative of the ideal shape of the reflecting surface and of the influence of the lens aberrations on the interference pattern from an initial signal representative of the sensed interference pattern.

Claims7

Dependent claims

An arrangement for testing a concave reflecting surface of a barrel-optic solid body for deviations of its actual shape from its ideal shape, comprising

means for emitting a laser beam;
optical means interposed between said emitting means and the reflecting surface to be tested and operative for so optically modifying said laser beam as to propagate between said optical means and the reflecting surface along a predetermined path that is substantially normal to the reflecting surface and to be reflected from the reflecting surface for propagation substantially along said predetermined path and through said optical means back toward the generating means as a return laser beam having a wave front indicative of the actual shape of the reflecting surface and any optical aberrations of said optical means;
means for forming an interference pattern between said laser beams;
and
means for evaluating said interference pattern, including
means for generating an initial signal representative of said interference pattern,
means for providing a reference signal representative of the ideal shape of the reflecting surface,
means for storing an additional signal representative of the influence of the aberrations of said optical means on the interference pattern, and
means for correlatedly subtracting said reference signal and said additional reference signal from said initial signal to obtain a final signal representative only of the difference between the actual and ideal shapes of the reflecting surface.

6 more elements

A method of testing a concave reflecting surface of a barrel-optic solid body for deviations of its actual shape from its ideal shape, comprising the steps of

a laser beam;
optically modifying the laser beam by at least one negative optical element so as to propagate to the reflecting surface to be tested along a predetermined path that is substantially normal to the reflecting surface and to be reflected from the reflecting surface for propagation substantially along said predetermined path means as a return laser beam having a wave front indicative of the actual shape of the reflecting surface and any optical aberrations of said optical element;
forming an interference pattern between said laser beams;
and
for evaluating said interference pattern, including
generating an initial signal representative of said interference pattern,
providing a reference signal representative of the ideal shape of the reflecting surface,
storing an additional signal representative of the influence of the aberrations of said optical element on the interference pattern, and
means for correlatedly subtracting said reference signal and said additional reference signal from said initial signal to obtain a final signal representative only of the difference between the actual and ideal shapes of the reflecting surface.

6 more elements

Dependencies are inferred from the claim text.

Arrangement for testing complex concave reflecting surfaces for shape deviations

Life of this patent

Arrangement for testing complex concave reflecting surfaces for shape deviations

Life of this patent

Abstract

Claims7