SU1677520A1 - Photoelectric measuring device - Google Patents

Abstract

The invention relates to an optoelectronic measuring technique, namely, photoelectric converters for contactless measurements of linear dimensions and displacements. the invention is to improve the accuracy of measurements of linear dimensions and displacements by fixing the moment of aiming at the test piece at the moment of polarity change of the signal from the photodetectors. The optical probe of the device is above the object being monitored and moves in the direction of the object along the guides 4. At the moment of touching the probe of the monitored surface, the polarity of the signal changes from the photoreceivers 11 installed on both sides of the prism edge 10. The time from the start of the optical probe movement to changes in the polarity of the signal from the photodetectors are judged on the movement of the object.3 Il.

Description

1

The invention relates to an optoelectronic measuring technique, namely, photoelectric converters for contactless measurements of linear dimensions and displacements, and can be used in automated control systems.

The purpose of the invention is to improve the accuracy of measurements of linear dimensions and displacements by fixing the moment of aiming at the monitored part at the moment of polarity change of the signal from photodetectors.

Figure 1 presents the scheme of the device; FIG. 2 shows the form of the output signal of the converter; on fig.Z - optical probe.

The photoelectric measuring device contains an illuminator 1 and a phototransducer 2, rigidly mounted on the traverse 3 at an angle to each other. The traverse 3 along the guides A from the actuator 5 can move progressively along the direction normal with respect to the surface of the object under test b and coinciding with the bisector of this angle. The lighter 1 and the transducer 2 are focused on point A, which lies at the intersection of their optical axes. Point A forms an optical probe of a photoelectric measuring device (FIG. 3). Lens 7 of the illuminator 1 builds an image of the radiating platform of the light source 8 in the plane passing through point A with an increase of 1: 1. As the light source 1, infrared emitters and semiconductor lasers with a radiation zone of about 5-10 microns can be used. The device also contains a phototransducer 9, a prism 10, installed in such a way that the optical axis of the phototransducer is normal to the surface of the prism, opposite the angle of 90 °, and two photoreceivers 11, connected in a differential circuit. The phototransducer 2 is connected to the input of the amplifier 12 of the photocurrent, which through the comparator 13 is connected to the control input of the electronic switch 14. The information input of the switch 14 is connected to the raster sensor 15 linear displacements, and the output to the digital readout unit 16.

Photoelectric measuring device operates as follows.

The mechanical part of the device is installed above the object to be monitored 6 so that the direction of movement of the crosshead 3 coincides with the normal to the surface being monitored, and the optical probe of the device (point A) is above the surface of the object being monitored 6. At the indicated position (Fig. 3) node 16. Then using the drive 5 traverse 3 together with

the illuminator 1 and the phototransmitter 2 move along the guides 4 towards the surface of the object 6. At the moment of coincidence of the surface of the object being monitored 6 with the optical probe (point B on

0 in FIG. 3), the source image is in the plane of the edge of the prism 10 and is divided equally by it (coordinated position). Differentially switched on photodetectors 11 fall on the same light fluxes of 5 currents, the amplitude of the output signal of the photovoltaic converter is zero, which corresponds to the point X0 (figure 2). At positions Xi and Xa, the image of source 1 is displaced relative to the edge of the prism 10, and receivers 11 on the photo попа receive different light fluxes. In these positions, the output signals are non-zero and have opposite signs. The polarity changes of the amplified signal are extracted5 with a comparator 13 of the electronic unit at the output of which a short pulse is generated. Upon receipt of the specified pulse in the electronic switch 14, the passage of pulses of the type

0 square wave, produced by a photoelectric raster sensor 15 linear displacements. The number of pulses passed from the beginning of the movement to the moment of passing through the coordinated position is recorded by the drop node 16 and displayed on the indicator board of this device.

Claims (1)

A photoelectric measuring device comprising an illuminator and a photoconverter, a linear displacement sensor and an electronic unit, an illuminator and a photoconverter are angled to each other with the movement of this angle along the bisector of this angle, and the photoconverter consists of a focusing optical system and a photoelectric sensor. and a straight prism, the edge at which the right angle lies in the focal plane of the focusing optical system and intersects its optical axis, and the photosensor is made in the form two identical photodetectors optically coupled to the side faces of a straight prism, characterized by 5 that, in order to improve the measurement accuracy, the linear displacement sensor is made in the form of a linear displacement raster sensor, the electronic unit consists of an amplifier, comparator, switch and digital readout node, photodetectors differentially connected to the input of the amplifier, the output of the amplifier through the comparator is connected to the control input of the switch, the information input of which is supplied by the keys to the linear displacement sensor, and the output to the digital readout node. Ho% t  X (Reg. 2 fig.Z.