SU641274A1 - Photoelectric device for checking rectilinearity - Google Patents

Description

This invention relates to a measurement technique, namely, devices for controlling straightness. A device for controlling linearity is known, comprising a laser, an optical system, a measuring carriage and a position-sensitive phototransducer, an information processing unit and a recorder 11). The disadvantage of this device is the low measurement accuracy due to refraction, the effect of air flow, the instability of the light source, the effect of which is different depending on the distance between the light source and the photoconverter. The closest in its technical essence to the proposed invention is a device for control. a linearity containing a light source, a photodetector, a moving carriage along the beam; which is in functional dependence on the current range between the light source and the receiver, and the recorder {2}. A disadvantage of the known device is the low measurement accuracy due to the refraction of the air flow and the instability of the light source. The purpose of the invention is to increase the accuracy of control over the entire measurement path. For this purpose, an additional photodetector, installed at a fixed distance from the light source, the output of which is connected to the input of the irradiance converter to an electrical signal, and a splitter installed on the carriage, is introduced into the device. The drawing shows a schematic diagram of the proposed device. The device contains a source of light I, forming a narrow beam of rays, a photodetector 2 mounted on a carriage 3 moving along the beam, a splitter 4 (translucent mirror) of a beam of rays emerging from a light source, a converter

5 irradiance of the photopronger 2 into an electrical signal, filter 6, the constant of which is functionally dependent on the current distance between the light source and the photoreceiver 2, the recording device 7, the photoreceiver 8, installed at a fixed distance from the source 1 of the light (in the particular case at the end of the test surface).

The device works as follows.

A light source 1, for example a laser (optical quantum generator), forms a narrow beam of rays directed towards the carriage 3, mixing along the surface, whose straightness must be measured.

The carriage is pre-installed near the light source and the circuit is adjusted so that the transmission coefficient is zero.

When moving the carriage along the controlled surface, depending on its profile, the carriage will occupy different positions relative to the axis of the light beam of rays.

Due to the fluctuations of the beam in the air path, the angular movements of the light source, the beam moves relative to the carriage, and at the output of photoreception 2 a signal appears that characterizes not only the surface profile, but also the beam fluctuations in the air path, the change in the light intensity distribution flow in the beam section.

The signal from the photodetector 8 characterizes only the fluctuations of the beam and the airway path, the angular displacements of the light source and the change in the intensity distribution of the light flux in the cross section of the beam. The signals from photodetectors 2 and 8 are fed to converter 5 to filter 6, where they are multiplied by

7;

gear ratios are added or subtracted and fed to a recording device 7.

Such a circuit eliminates the error of the measurement result due to the inconsistency of the position of the light source, due to the change in the intensity distribution of the light flux in the beam section, and reduces the dispersion of the measurement result caused by fluctuations of the beam in the air path.

Claims (2)

Invention Formula A photoelectric device for controlling the linearity, comprising a light source, a photodetector, a carriage along the beam, on which a photodetector is installed, a converter for irradiating a photodetector into an electrical signal, the input of which is connected to the output of a photodetector; a projection bias transducer of the beam in the photo-receiver plane into an electrical signal, a filter whose time constant is functionally dependent on the current distance between the light source and the receiver, and a recorder, characterized in that, in order to improve the control accuracy, the device is equipped with a second photo-receiver, located at a fixed distance from the light source, the output of which is connected to the input of the aE5 radiation converter into the electrical signal, and a splitter mounted on the carriage. Sources of information taken into account in the examination L USSR Author's Certificate No. 370462, G 01 B 11/30, 1973. 2. USSR author's certificate No. 438867, G 01 B 11/30, 1972.