RU2804679C1 - Fibre-optic displacement sensor - Google Patents

Abstract

FIELD: fibre-optic displacement transducers.

SUBSTANCE: device comprises a source of optical radiation, a fibre optic light guide, a photodetector, an electronic information processing unit. The output of the source of optical radiation is fixed at the first end of the fibre-optic light guide, at the second end there is a perceiving zone made in the form of a bevel, which forms a prism of total internal reflection. The output of the fibre-optic light guide is connected to the input of the photodetector. The output of the photodetector is connected to an electronic information processing unit capable of calculating displacements. The output of the electronic information processing unit is the output of the entire fibre-optic displacement sensor.

EFFECT: increase in the accuracy of measuring the movement of optically transparent moving objects in the submicrometer range.

1 cl, 1 dwg

Description

The invention relates to measuring technology, in particular to fiber-optic displacement transducers, and can be used to measure displacement in the submicrometer range.

A fiber-optic displacement sensor is known (RF application for invention 2272985, G01B 1/00, 03/27/2006), containing a polarized light emitter, a fiber light guide, a recorder, and an emitter.

The reasons preventing the achievement of the technical result indicated below when using a known device is the mounting of a reflector, a polarized light emitter and a receiver with a vertical lens holder on the controlled object, which makes it impossible to use it for controlled objects that should not be subjected to additional mechanical stress.

The closest device for the same purpose to the claimed device in terms of the set of characteristics is a fiber-optic displacement sensor (RF application for invention 2489679, G01B 11/02, G01D 5/26, 10/08/2013) (prototype) containing a source of optical radiation, the output of which is connected to the input of the incoming fiber-optic light guide, the first and second outlet fiber-optic light guides, the outputs of which are connected to the inputs of the first and second photodetectors, respectively, an electronic signal processing unit.

This device improves the accuracy of measuring the movement of an object by receiving a signal proportional to the movement of the moving object, which does not depend on fluctuations in the power of the radiation source.

The disadvantage of the proposed fiber-optic displacement sensor is the need to attach a reflective element to a moving object, which leads to a change in the state of the surface, creates additional mass, and, as a result, deteriorates the measurement accuracy in the submicrometer range of movements.

The purpose of this patent is to eliminate this drawback. The technical result is an increase in the accuracy of measuring the movement of optically transparent moving objects in the submicrometer range.

The technical result is achieved in that the fiber-optic displacement sensor, consisting of an optical radiation source, the output of which is fixed at the first end of the fiber-optic light guide, the output of which is connected to the input of the photodetector, the output of which is connected to the electronic information processing unit, has a receptive zone located at the second end and made in the form of a bevel, which forms a prism of total internal reflection, and the photodetector is mounted on a fiber-optic light guide in such a way that the optical beam (optical communication), reflected from the receptive zone, falls on the photosensitive zone. The bevel angle of the fiber optic light guide is calculated by the formula:

where n ₁ is the refractive index of the fiber optic light guide core; n ₂ is the refractive index of the medium separating the moving object and the receiving zone (vacuum or gaseous environment).

In FIG. 1 shows a diagram of the device.

Accepted designations:

1 - source of optical radiation;

2 - fiber-optic light guide;

3 - photodetector;

4 - electronic signal processing unit;

5 - receptive zone;

6 - medium separating the moving object and the receiving zone;

7 - moving object.

The device consists of an optical radiation source 1, a fiber-optic light guide 2, a photodetector 3, an electronic information processing unit 4, and a receiving zone 5.

The optical radiation source 1 is attached to the first end of the fiber-optic light guide 2, at the second end there is a receiving zone 5, made in the form of a bevel, which forms a prism of total internal reflection, a photodetector 3 is attached to the output of the wave-optic light guide, the output of which is connected to the electronic unit signal processing 4. The output of the electronic signal processing unit 4 is the output of the entire fiber-optic displacement sensor.

The claimed device operates as follows: after turning on the fiber-optic displacement sensor, the optical radiation source 1 with wavelength X emits a light beam of constant power. Optical radiation enters the fiber-optic light guide 2 and is reflected from the receiving zone 5. A change in the distance between the moving object 7 and the receiving zone 5 leads to a change in the reflectivity of the structure “perceiving zone 5 - medium 6, separating the moving object 7 and the receiving zone 5 - moving object 7", which leads to a change in the power of optical radiation incident on the photodetector 3. The optical radiation power reflected from the receiving zone 5 is recorded by the photodetector 3 connected to the electronic signal unit 4. According to the dependence of the optical radiation power on the width of the gap between the receiving zone 5 and the moving object 6 determines the movement of the moving object 7.

As an optical radiation source 1, an optical radiation source LLS-LS-215 manufactured by OPTIKON can be used.

Photodiode IG17X250S4I manufactured by Laser Components can be used as photodetector 3.

As a fiber-optic light guide 2, you can use polarization-maintaining fiber PM1550-XP manufactured by THORLABS.

Thus, we offer a fiber-optic displacement sensor with increased accuracy in the submicrometer range without additional devices that mechanically act on a moving object.

Claims (1)

A fiber-optic displacement sensor containing a source of optical radiation, the output of which is fixed at the first end of the fiber-optic light guide, the output of which is connected to the input of a photodetector, the output of which is connected to an electronic information processing unit, characterized in that the receiving zone is located at the second end and is made in the form of a bevel, which forms a prism of total internal reflection, the photodetector is mounted on a fiber-optic light guide in such a way that the optical beam, reflected from the receiving zone, falls on the photosensitive zone of the photodetector.

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