SU1717952A1 - Reflector for optoelectronic device for measuring angles - Google Patents

Abstract

The invention relates to a measuring and control technique, namely, to reflective elements of optoelectronic systems designed to control the angles of rotation of an object (twisting) around a given axis. The purpose of the invention is to simplify the design of the reflector. A parallel beam of rays formed by the radiating channel of the autocollimator falls on the entrance face of the tetrahedron. Part of the beam enters the tetrahedron through its refractive surface, is reflected from the other three faces, and emerges from the tetrahedron through a wedge. Due to the anamorphosis properties of the tetrahedron and the wedge, the beam divergence angle increases in a plane parallel to the main cross section of the wedge, which leads to a stretching of the image of the brand of autocollimator in the analysis plane of the autocollimator. 3 il.

Description

The invention relates to a measuring and control technique, namely, to reflective elements of optoelectronic systems designed to control the object's rotation angles (twisting) around a given axis and using anamorphosis to measure the phenomenon, and can be used as a control element of an autocollimator.

A reflector, consisting of a triple-prism reflector with straight dihedral angles between the reflecting faces, returns the reflected beam in the direction opposite to and parallel to the direction of the incident beam and the optical wedge located in front of the reflector, half the working aperture. Reflector.

However, the presence of a wedge in front of the reflecting element causes a deflection of the beam of rays emerging from the reflector relative to the incident beam. This limits the distance between the basic and control measurement objects and the range of measured angles, since as the distance changes, the output beam of rays is screwed by the lens mount of the receiving part.

The design of the reflector involves the use of two photodetectors as part of an autocollimator, which complicates the circuit of the photodetector. In addition, a measure of the twist angle is the magnitude of the displacement of the energy center of the image of the mark by the position-sensitive photodetector, which determines the Significant measurement error due to the heterogeneity of the sensitivity across the receiver area and the instability of the photodetector parameters in time.

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The closest in technical essence and problem to the proposed one is a reflector of an autocollimation device containing a retroreflector, the angles between the faces of which are 90 °, and a telescopic anamorphic system of two identical optical wedges installed in front of it along the beam at its entrance pupil Thereby, the first side of the first wedge, refracting the face of the first wedge, is perpendicular to the optical axis of the reflector, and the angle of the refracting angle in each wedge and the angle 01.2 between the second refracting face the first wedge and the first refractive edge of the second wedge are determined by the views

0 afcsln; 01.2 arcsln (n - sin 0j,

Anz.-1

where n is the refractive index of wedges;

And the coefficient of the anamorphosis of the wedge system.

Thus, in the described reflector, the incident and reflected beams of the beams are parallel and the anamorphosis coefficient is different from A - 1.

When the controlled object rotates together with the reflector mounted on it by the twist angle, the divergence of the beam of the autocollimator passing through the reflector changes as a result of the plane of action of the anamorphosis of the wedge system, which leads to a change in the shape and aspect ratio of the brand image. The magnitude of the twist angle is defined as the ratio function.

Y X where x and y characterize maximal y y x

Other dimensions of the image mark on two orthogonal axes.

The disadvantage of this reflector is the complex structure for ensuring the exact mutual orientation of the three optical elements relative to each other: the first wedge relative to the second and the anamorphosis system (the first and the second wedge) relative to the reflector. This circumstance also complicates the adjustment of the reflector components.

The aim of the invention is to simplify the design.

This goal is achieved due to the fact that in a reflector containing a glass tetrahedron with one of the dihedral angles between the reflecting faces 90 ° and an anamorphosis system installed in the form of an optical wedge installed in front of it at half of its entrance pupil, there are two other dihedral angles between the reflecting faces of a glass tetrahedron are 90 ° –d, the edge of the dihedral angle between the refracting faces of the optical wedge lies in a plane perpendicular to the refractive edge of the glass tetrahedron and the dihedral angle passing through the edge th corner

a tetrahedral reflector of 90 °. the value of the anamorphosis factor A, as well as the angle 01.2 between the refractive surface of the tetrahedral reflector and the first refractive surface

wedges are determined from expressions

20

And V 1 -sln42V20). VI -sJn (ft). 1 - n2sin2 () 1 -n2sin2 (02)

0

01.2 arcsin (nsln2 (2)); arcsln (nsln 0z) - 02 arcsin (nsin (2))

 01.2.

5 where n is the refractive index of the material of the glass tetrahedron and the wedge; 02 is the refracting angle of the wedge. FIG. 1 shows the proposed reflector, a general view; in fig. 2 - stroke pattern

Q rays through the components of the reflector; Fig. 3 is a diagram of the path of the rays through the components of the equivalent optical scheme of the reflector.

The reflector includes (Fig. 1 and 2) a glass tetrahedron 1, two dihedral angles between the reflecting faces of which (angles with edges 1 and 1) are equal to 90 ° -. 5 (where d is some angle), and the third dihedral angle (with edge 1 /) is 90 °, and optical

wedge 2.

The reflector is associated with the XYZ coordinate system, the OX axis of which is parallel to the optical axis of the autocollimator lens. The reflector is intended to be used as a control element of an autocollimator for measuring the angle of rotation relative to the axis OX (twisting angle).

The reflector works as follows (Fig. 2).

A parallel beam of rays, formed by a radiating channel of an autocollimator (not shown), falls on the entrance face of a glass tetrahedron. Part of the beam enters

5 to the glass tetrahedron 1 through its refracting face, is reflected from the other three faces and emerges from the glass tetrahedron through the wedge 2, remaining parallel to the beam incident on the reflector. Due to the anamorphosis properties of the glass tetrahedron and the wedge, the beam divergence angle increases in the plane of anamorphosis parallel to the main section of wedge 2, which leads to an increase in A times (stretch) the image of the brand of autocollimator in the plane of analysis of the autocollimator. When the controlled object is rotated together with a reflector mounted on it at the twist angle, the plane of action of the anamorphosis also rotates, with the result that the shape of the image is distorted. This leads to a change in the values of the parameters x and y, which characterize the maximum dimensions of the mark along two orthogonal axes, which is recorded by the receiving part of the autocollimator (not shown). From the x and y values obtained, the twist angle y is determined.

F o rm u l a, i z o b e te n u

A reflector for an optoelectronic angle measuring device containing a retroreflector and an anamorphosis system installed in front of it along the path, characterized in that. that, in order to simplify the construction, the retroreflector is made in the form of a glass tetrahedron with one angle between the reflecting

facets equal to 90 °. and two other dihedral angles equal to 90 ° - e. where e is the magnitude of the deviation of the angles from 90 °, the anamorphic system is installed on the half of the entrance pupil of the retroreflector and made in the form of an optical wedge oriented so that the edge of the dihedral angle between the refracting edges the optical wedge is in a plane perpendicular to the refracting face of the retroreflector, the tetrahedron and the wedge form a telescopic system, and the anamorphosis coefficient A and the angle between the refractive surface of the glass tetrahedron and the primary On the side of the incident rays, the refractive surface of the wedge Qt, 2 is determined from the dependences

l V 1 - slr ((5). P - sin2 D. 1 () 1 - n2sln2 ($)

01.2 arcsin (nsin (2 v / Td)); arcsin (nsin ft) - 92. arcsin (nsln (2 VTd)).

where n is the refractive index of the material of the glass tetrahedron;

ft is the wedge refracting angle.

qpRi reflected

Connect axle lshd. sbshba

O & mOKMJIUMJL-ll lp m T

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T.-vptoMW ..

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Prrlomlttsa face

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Output. Wilding

OSHPSHOYA AXIS

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А ± Ја

Our affmfl / m / Miuiamopa &

fej

Claims (2)

FORMULA. Sample 20 Reflector for an optoelectronic angle measuring device, comprising a retroreflector and an anamorphous system installed in front of it along the rays, characterized in that. that, in order to simplify the design, the reflector is made in the form of a glass tetrahedron with one angle between the reflecting faces equal to 90 °. and two other dihedral angles equal to 90 ° - d. where d is the deviation of the angle values from 90 °, the anamorphous system is installed on half of the entrance pupil of the retroreflector and is made in the form of an optical wedge, oriented so that the edge of the dihedral angle between the refracting faces of the optical wedge is in the plane perpendicular to the refracting face of the retroreflector, the tetrahedron and wedge form a telescopic system, and the anamorphosis coefficient A and the angle between the refracting surface of the glass tetrahedron and the first c side of the incident rays refracting Qi wedge surface 2 is determined from the dependence of A = 1 ~ Sln ^ 2? 2 ~ d). ~ 1 siny (&) ~. 1 - n2sln2 (2V2 ~ ό) 1 - n2sln2 (ft) 01.2 = arcsin (nsln (2 VzFd)); arcsin (nsin 0g) - 02 = arcsin (nsln (2 VZd)). where n is the refractive index of the material of the glass tetrahedron; 0g is the refracting angle of the wedge. alttysh, axis o & toshmimltora ORP reflected ort. Yashki- J upto shsha. Fi.g1 Fi.2.3