SU765775A1 - Optical displacement-to-code converter - Google Patents

Description

one

The invention relates to the field of optoelectronics, automation and measurement technology. It can be used in geophysical equipment, in communication systems and inertial navigation, for example, for converting and measuring mechanical magnitudes, in medical instrumentation. Optical motion transducers into an electrical signal are known, which can then be converted into a digital code fl. Their disadvantage is the low conversion accuracy.

The closest in technical essence and the achieved result; is an optical displacement transducer into a code containing a light source, a bundle of optical fibers, the inputs 20 of which form a ruler, and the outputs are connected to photoreceivers by the number of optical fibers, a position decoder with an indicator connected to the outputs of photodetectors 2.25

The disadvantage of it is a small dynamic range.

The aim of the invention is to increase the dynamic range of the converters .30

This is achieved due to the fact that it additionally contains a light direction modulator with a damper and a compensator attached to it, buffer amplifiers and a multi-input subtractor unit, with the amplifier inputs connected to photo detectors and the outputs of the amplifiers connected to the position decoder .

To improve the measurement accuracy, the converter can also contain an additional analog-to-digital converter, the inputs of which are connected to the outputs of the subtraction unit, and the output is connected to the lower digits of the indicator.

FIG. Figure 1 shows the block diagram of the proposed optical motion to code converter; FIG. 2 shows a receiving part of a converter equipped with a decoder, a recorder and an analog-digital converter.

The optical displacement transducer to the code (Fig. 1) contains a light source 1, a driver 2, a modulator (sensitive element) 3, interacting with a compensator 4, a damper 5 and an input source 6

effects and optically coupled to the ends of the.-C fibers connected through photodetectors F., and amplifiers K.. . To the inputs of block 7 subtraction.

The outputs of the amplifiers (Fig. 2) are additionally connected to the decoder 8 associated with the higher bits of the indicator 9 and the recorder 10, the lower bits of which are connected through the analog-to-digital converter 11 with the subtraction unit 7.

The optical motion to code converter operates as follows.

The beam of light (Fig. 1) of the source 1 is formed by the shaper 2 and through the modulator 3 enters the ends of the light guides C, .. C. If the input signal is absent (Fj, y 0), then the beam is divided by optical fibers into two beams of equal intensity, which are recorded by photodetectors F and F

are coming

and through amplifiers

to the inputs of the subtraction unit 7, the signal at the output of which will be zero

 ABOUT

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Under the action of the input signal, the beam is deflected by the modulator and in one of the light guides the light intensity will be higher than in the other, which leads to the appearance of a signal at the output of the subtraction unit, which is proportional to the deviation angle and, consequently, to the input signal.

With a large dynamic range Fg, y, the beam of light will be deflected at a considerable angle and may be received by another pair of fibers C and C (Fig. 2) installed along the direction of movement of the beam of light. This deviation is recorded by the corresponding photodetectors F and $ - and through the amplifiers X and is fed to the input of the subtraction unit 7, made multi-input, and at its output the signal will be proportional to the unbalance of the beam relative to the input ends of the optical fibers and C.

This allows you to measure, for example, the amplitude and mode of oscillation of the beam, and hence the input signal, against the background of its large, for example, static components.

The magnitude of these components can be registered by means of a decoder 8 (FIG. 2) in the higher bits of the digital indicator 9 and the recorder 10.

For digital indication and registration of small oscillations of the input signal, the converter is equipped with an analog-to-digital converter 11, which represents in digital form the magnitude of the beam displacement relative to the two optical fibers illuminated by it and registers them at the lower bits of the indicator 9 and the recorder 10.

The proposed construction, namely the modulator unit, can be made with minimal dimensions, for example, in a thin hollow needle of a medical syringe. In it, as a modulator (sensing element), a thin diaphragm can be applied, tensioned onto the end of the needle with a scanning optical fiber fixed at its center and two receiving optical fibers with a diameter of -v. 10 microns each. The needle diameter can be increased to 0.5-0.1 mm with the thickness of a three-core fiber cable. 0.06 mm.

 Technical and economic indicators of the effectiveness of the proposed device, provided with a new set of features, can be represented as follows.

0 1. With accuracy and dynamic range, the diameter of the transducer without a registration scheme can be made 0.1 mm.

2. When dynamic range

5 (lO -lo) diameter does not exceed 10mm.

3. The converter can be used as a miniature sensor, mainly mechanical quantities, a switch, etc.

Q 4. The sensor is simple and cheap to manufacture and operate.

Claims (2)

1. The optical displacement transducer into a code containing a light source, a bundle of light guides, the inputs of which form a ruler, and the outputs are connected to photodetectors - 0 according to the number of optical fibers, a position decoder with an indicator, connected to the outputs of photodetectors, characterized in that, in order to increase the dynamic range, 5 it further comprises a light direction modulator with attached damper and compensator, buffer amplifiers and a multi-input subtractor, the POWER inputs are connected to the photodetectors, and the outputs of the amplifiers are connected to the inputs of the subtractor, the outputs of which are connected to the position decoder. 2. The transducer according to claim 1, characterized in that, with purpose of improving measurement accuracy. it contains an additional analog-to-digital converter, the inputs of which are connected to the outputs of the subtraction unit, and the output is connected to the lower bits of the indicator. Sources of information taken into account in the examination 1. Bayi-Salen R. Fiber Optic Displacement Sensor for Research displacing the surface of a solid sample irradiated with an intense electron beam. Instruments for scientific research. 1975, p.80. 2. USSR author's certificate 296071, cl. G 02 F 2/00, 1971 (prototype). fh, with-" 1