SU1241064A2 - Optronic converter of turn angle to electric signal - Google Patents

Abstract

The invention relates to the field of measurement technology, in particular, to devices that provide an indication of the angles of rotation of a controlled object from the baseline (around the line connecting them), and can be applied in machine-tool construction and geodesy. The aim of the invention is to increase the accuracy by eliminating the influence of the unevenness of the position of the polarization plane on the light field. The radiation flux from the emitter, passing the lens, polarizer, is polarized, in the direction of the polarization plane of the polarizer. A quarter-wave plate converts linearly polarized radiation into circulating polarized radiation. After the modulator, the radiation contains two components with mutually orthogonal directions of the polarization plane (along the optical axis and perpendicular). The light emission phase of one of the components changes with respect to the other with the frequency of sound vibrations. Due to the fact that radiation is a set of electromagnetic waves with different wavelengths, a set of waves with different polarization states, different signs and phases is formed at the output of the optical phase shifter. When these waves are summed, they produce radiation consisting of two parts that are anti-phase-modulated with equal amplitudes and mutually perpendicular directions of the polarization planes (along the optical axis of the phase shifter and perpendicular to it). At an angle between the optical axes of phase shifters 45, the amplitudes of the components will be and the total light flux will not be modulated at any position of the polarization plane of the analyzer. In this case, there will be no signal at the output of the amplitude-phase detector. When the phase shifter rotates together with the analyzer (rum relative to the optical phase shifter by an angle (one of the radiation components increases in proportion to the angle of rotation. At the output of the photodetector, an alternating electric signal will turn proportional to the angle of rotation in phase or antiphase Invention - supplementary to ed. St. No. 1013999.: 1 il, § (O th 4 o ISO

Description

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The invention relates to a measurement technique, in particular, to devices that provide an indication of the angles of rotation of a monitored object relative to the baseline (around the line connecting them), and can be applied in the machine tool industry and geodesy.

The aim of the invention is to improve the accuracy by eliminating the unevenness of the position of the polarization plane.

The drawing shows the scheme of the proposed Converter.

The optoelectronic converter comprises an emitter 1, a lens 2, a polarizer 3, a quarter-wave plate 4, a phase modulator in the form of a glass parallelepiped, a piezo-generator 6, rigidly fixed. on the verge of a modulator 5, a voltage generator 7, an optical phase shifter 8, a second optical phase shifter 9. The optical phase shifters 8 and 9 are made with a phase shift of more than 100 and are made of a material having double refraction. In addition, the converter contains an analyzer 10. The second optical phase shifter 9 is located between the first phase shifter 8 and the analyzer 10, a gesture- ,. connected to the first phase shifter 8 and oriented in such a way that its optical axis makes an angle with the optical axis of the analyzer. The device also contains a lens 11, photoprints. capacitor 12 and amplitude-phase detector 13.

The opto-electronic converter works as follows.

The radiation flux from the emitter 1, passing the lens 2 and the polarizer 3, is polarized in the direction of the polarization plane of the polarizer 3. The quarter-wave plate 4 converts linearly polarized radiation into circularly polarized. After the modulus of phase 5, the radiation contains two components with mutually orthogonal directions of the polarization plane (along the optical axis and perpendicular to it). The light emission phase of one of the components varies in relation to the other with a frequency of sound vibrations. Due to the fact that the radiation is a set of electromagnetic waves with different wavelengths, the output of the optical phase shifter 8 forms a set of j waves with different polarization states.

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different signs and phases. The summation of these waves produces radiation consisting of two parts that are modulated in antiphase with equal amplitudes and mutually perpendicular directions of the polarization planes (along the optical axis of the phase shifter 8 and. Perpendicular to it). In this case, each part of the radiation contains two components that are modulated in antiphase. At an angle between the optical axes of phase shifters 8 and 9 45, the amplitudes of the components are equal and the total luminous flux

not modulated at any position of the polarization plane of the analyzer. In this case, the output of the amplitude-phase detector 13 is no signal. When the phase shifter rotates 9 with the TO analyzer relative to the optical phase shifter 8, by an angle + (iodine of the radiation components increases in proportion to the angle of rotation. At the photo output of the receiver 12, an alternating electric turn signal is generated, which is the proportional angle rotation in phase or antiphase (depending on the sign of the angle) with the reference signal, after the detector 13 from the voltage generator 7 is applied.

The uneven position of the plane of polarization of the analyzer 10 over the light field, as well as the instability of its position within small limits do not cause a change in the output signal. At the output of the phase detector 13, there is always zero at an angle between the optical axes of the phase shifters 8

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and 9 equals 45. When the angle ot between optical axes is changed by a certain amount, the signal changes in proportion to this value.

Claims (1)

Thus, the non-uniformity of the polarization plane of the light field does not change the output signal. Claims of the invention An optical-electronic angle-to-electric converter of an auth. St. No. 1013999, about t-l and h and y p i and with. in order to improve accuracy, it is equipped with a second optical phase shifter, located between the first phase shifter and the analyzer, rigidly connected with it and oriented so that its optical axis makes an angle with the optical axis of the analyzer. 2 3 tf 5 8 / Lj