SU1652819A1 - Optronic device for measuring linear displacements of an object - Google Patents

Abstract

This invention relates to instrumentation technology. The purpose of the invention is to improve the accuracy by eliminating the random component of the error due to the amplitude-time instability of the radiation source. The radiation flux from the pulsed radiation source 1 is divided by a beam splitter 2 into two parts, each of which comes to a corresponding face of a doubled prism 5 installed in the focus of the lens 6, the edge of which is orthogonal to the optical axis of the source 1 and the optical axis of the lens 6. image of this rib. The separation of signals corresponding to radiation fluxes perceived by one and the other input edges of the prism 5 is accomplished by delaying the signal propagating in one of the beamsplit 2 channels via the optical delay line 4. The offset of the photoreceiver 7 associated with the object in the transverse direction relative to the axis of the lens 6 is determined by the amplitude error signal of the (pulsed) signals from the output of the photopronger 7 corresponding to the radiation fluxes from the two input faces of the prism 5, linearly related to the amount of lateral displacement. A positive effect is achieved by illuminating both faces of the prism 5 with radiation from the same radiation source 1, which compensates for the random error from the temporal instability of the luminance of the radiation source 1 and thus provides an increase in accuracy. 1 hp f-ly, 2 ill. ъ (L

Description

The invention relates to a measuring and measuring technique and can be used to determine linear displacements of objects in the transverse direction in mechanical engineering, construction and other parts of the technique.

The aim of the invention is to improve the accuracy of tl by eliminating the random component of the error due to the amplitude-time instability of the radiation source.

FIG. 1 predlozhena functional scheme vciroizstva; Fig. 2 is a timing diagram illustrating the operation of the device.

The device contains (Fig. 1) a pulsed optical radiation source 1, located along the beam splitter 2, the optical filter 3 and the optical delay line 4, installed respectively in the main and side channels of the splitter 2, a dihedral prism 5 optically connected through the corresponding faces with the outputs the light filter 3 and the optical line 4 of the projectile, lens 6, while the edge of the prism 5, common to its input faces, is the focal distance from the plane of the lens 6 and orthogonal to the optical axis of the radiation source 1 and about the lens axis 6, and the photodetector 7, the amplifier 8, the input of which is connected to the output of the photoreceiver 7, and the error signal extraction unit (not shown in Fig. 1) formed by the first and second elements 9 and 10 of the sample-storage and the synchronizer 11, inputs which are connected to the output of the amplifier 8, and the subtractor 12, the first and second inputs of which are connected respectively to the outputs of the first and second elements 9 and 10 of the sample-storage, control inputs of which are connected respectively to the first and second outputs of the synchronizer 11, the third output One of which is connected to the third input of the subtractor and whose output is the output of the device.

The optical delay line 4 is made in the form of a fiber waveguide whose length is not less than the product of the pulse duration of the radiation source 1 by the speed of light in the fiber material, and the light filter 3 is made with a transmittance equal to the transmittance of the optical delay line 4.

The device works as follows.

Pulse 11 (Fig. 2) of duration T1, formed by the radiation source 1 (Fig. 1), the passage through the beam splitter 2, is divided into two parts. One of the parts of the optical beam, the passage through the main channel of the splitter 2 through the optical filter 3, falls on one of the faces of the prism 5, the other along the side channel of the beam splitter

five

0

five

0

five

0

five

0

five

bodies 2 through the optical line 4 delays - on the other side of the prism 5, having undergone a delay duration TZ. The lens 6 forms on the photosensitive surface of the photodetector 7 an image of a prism 5, the faces of which are illuminated by the radiation of the radiation source 1. Since the condition is met, two electric pulses 12 and 13 are formed at the output of the photodetector 7 (Fig. 2). The delay time T2 is determined by the propagation time of the light from the prism 5 (Fig. 1) to the photosensitive surface of the photodetector 7. The amplitudes of the pulses 12 and 13 (Fig. 2) are proportional to the flux values of the radiation from the respective faces of the prism 5 (Fig. 1). Consequently, the difference DF (Fig. 2) of the amplitudes of the pulses 12 and 13 corresponds to the magnitude of the displacement (in the transverse direction) of the photo-reception of the gycl 7 (Fig. 1), rigidly connected with the object (not shown in Fig. 1), object 6 The signals are amplified by the amplifier 8. On the front of the first pulse, the synchronizer 11, taking into account the corresponding delay, places the first sampling-storage element 9 in the storage mode. Similarly, the second sample-storage element 10 is switched on the front of the second pulse. After the additional delay required to complete the transients, the synchronizer 11 generates an enable signal for the subtractor 12, the output of which produces a signal proportional to the difference in amplitudes, the magnitude of which is linearly related to the linear displacement of the object.

Thus, the illumination of both faces of the prism 5 by radiation from the same radiation source 1 eliminates the random component of the error associated with the fluctuation of the luminance intensity of the radiation source 1 due to thermal processes and other destabilizing factors. corresponding to radiation in different half-planes, is carried out by their separation in time using an optical delay line 4 installed in the side channel of the splitter 2.

Claims (2)

Claim 1. Optoelectronic device for determining linear displacement 516 an object containing a pulsed optical radiation source, a dihedral prism along the radiation path, a lens and a photodetector, a rib of a dihedral prism is located in such a way that it is at a focal distance from the lens's softness and orthogonal to the optical axis of the radiation source and the optical axis of the lens, and selection of the error signal, the input of which is connected to the output of the photodetector, characterized in that in order to increase the accuracy, it is equipped with a light divider mounted between tim and the prism, optical filter and optical delay line with where TK - time delay lines, T1 - source pulse width established between sve96 a splitter and a prism, respectively, in the main and side channels of the light divider, the error signal extraction unit is made in the form of two sample-storage elements and a synchronizer, whose inputs are combined and are the input of the unit, and the subtractor, the first and second inputs of which are connected respectively to the outputs of the first and the second element of the sample storage, control the inputs of which are connected respectively to the first and second outputs of the synchronizer, the third., the output of which is connected to the third input of the subtractor, the output of which It is the output device. 2. A device according to claim 1, characterized in that the optical delay line is made in the form of a fiber light guide. 1