SU1578457A1 - Interferometer for measuring linear displacements - Google Patents

Abstract

The invention relates to a measurement technique, specifically to interferometers for measuring small (0.5 µm) displacements. The purpose of the invention is to reduce the size and increase the accuracy of measurement by placing the components of the interferometer along the axis of the light beam and making it possible to bring the measuring pulses to the maximum value. The light beam produced by the light source 1 is divided by a translucent mirror 2 into a reference beam passing through its semi-transparent surface and a measuring beam reflected from it. The measuring beam is reflected from the reflector 5 and is connected to the reference one on the semi-transparent surface of mirror 3. As the reflector 5 moves along the Y axis in the zone of the light receiver 6, the interference pattern is formed in the form of alternating dark and light stripes. The light receiver 6 generates pulses, the number of which is proportional to the displacement of the reflector 5. Light source 1, mirrors 2 and 3 and light receiver 6 are located on the same axis, and the plane-parallel plate 4 is installed with the possibility of rotation about this axis. 1 il.

Description

The invention relates to a measurement technique, more specifically to interferometers for measuring small (0.5 µm) displacements.

The purpose of the invention is to reduce the size and increase the accuracy of change by placing the components of the interferometer along the axis of the light beam and due to the possibility of fine-tuning the measuring pulses to the maximum value.

The figure shows a schematic diagram of an interferometer for measuring linear displacements.

The interferometer contains optically coupled light source 1, translucent mirrors 2 and 3, an optically transparent plane-parallel plate 4, a corner reflector 5, which can consist of both two and three reflecting surfaces, and a light receiver 6.

The interferometer works as follows.

The light beam produced by the source with a peak of 1 light is divided by a semitransparent mirror 2 into a reference one that has passed through its translucent surface, and into a measuring one reflected from it. The measuring beam is reflected from the reflector 5 and is connected to the reference one on the semi-transparent surface of mirror 3. When the reflector 5 moves along the Y axis in the zone of the light receiver 6, an interference pattern in the form of alternating dark and bright bands (spots) is formed. The light receiver 6 produces pulses whose number is proportional to the displacement of the reflector 5

Claims (1)

A plane-parallel plate 4 is necessary for the final alignment of the reference and reflected rays on. the receiver 6 of the light, flowing as an adjustment of the movement of the mirrors 2 and 3 and the corner reflector 5, simultaneously leads both to a shift of the reference and measuring rays parallel to each other, and to a change in the angle between them. The plane-parallel plate 4 moves during alignment, turning around the optical axis of the interferometer. The described scheme allows for better alignment of the interferometer, as well as to carry out operational tuning in order to compensate, for example, temperature deformations in the course of operation. As a result, the amplitude of the measuring pulses can be increased to a maximum value and, accordingly, the measurement accuracy can be improved. Invention Formula Interferometer for measuring whether. displacements containing an optically coupled light source, two translucent mirrors located in mutually perpendicular planes, and a light receiver, characterized in that, in order to reduce overall dimensions and improve measurement accuracy, it is provided with a plane-parallel plate located between the mirrors, the source The lights, mirrors and the light receiver are located on the same axis, and the plane-parallel plate is installed with the possibility of rotation relative to. this axis.