SU1753261A1 - Method to measure right angle of bp-180 @@@ prisms - Google Patents

Description

The control unit is made to check the right angle. In this case, the second reflective prism is made in the form of a prism-trihedron or prism BR-1800 and is an auxiliary 2,

A significant disadvantage of the method is the relatively low measurement accuracy due to the angular errors of the auxiliary reflective prism and its low sensitivity. The angular distance between the autocollimation images of the mark observed by the actor collector 8 is proportional to only the quadruple error of the measured right angle. In addition, the measurement angle controls the right angle of only one prism, and an auxiliary reflective prism is needed to perform the measurement.

The aim of the invention is to improve the accuracy and performance of the measurement.

The goal is achieved by the method of measuring the right angle of the BR-1800 prisms, which consists in directing the radiation of the autocollimator to two prisms simultaneously, the first of which is set so that it overlaps the upper part of the collimated beam of rays, the second is on the optical axis an autocollimator with a base to it, by means of a flat reflector, make autocollimation images of the mark and determine their position in the field of view of the autocollimator; move the second prism so that it overlaps the lower part of the collimated the first beam of rays, a first prism is mounted on the second place, again by plotting a planar reflector autocollimator image of the brand, and the control is performed at two positions of each of the prisms in position in the field of view autocollimator images.

FIG. Figures 1 and 2 show a functional diagram of a device that implements a method for measuring the right angle of prisms of the BR-1800 at their two positions.

The device contains an autocollimator 1 and a flat mirror 2, the reflecting surface of which is located parallel to or close to the optical axis of the autocollimator 1.

The method is carried out as follows.

In the course, for example, of the upper part of the collimated beam of rays emerging from the autocollimator, under the mirror 2, the first measurable prism 3 of the BR-1800 type is installed. The main section of the prism 3 is perpendicular to the plane of the mirror 2 and parallel to the optical axis of the autocollimator 1. The plane of symmetry of the right angle of the prism 3 is also approximately perpendicular to the plane of the mirror 2 and the edge of the right angle is facing it. The prism 3 overlaps approximately half of the collimated beam of the autocollimator 1. The second measured prism 4 of the BR-1800 type is installed on the optical axis of the autocollimator with its base and behind the first prism 3 by the main section plane parallel to its plane of the main section 2 and edge of This angle is approximately on the optical axis. With direction

on the prisms 3, 4 of the collimated beam of rays, its upper part falls on the side of the prism 3 facing the autocollimator 1 and after reflecting from it on the mirror 2, reflecting on which

the path returns to the autocollimator 1. The lower part of the collimated beam of rays emerging from the autocollimator 1 falls into the prism 4 and after reflection from its catheter faces falls onto another catheter

the face of the prism 3 and after reflection from it on mirror 2. Reflected from mirror 2 this part of the beam of rays along the same path returns to autocollimator 1 (Fig. 1). Due to errors in the right angle of both prisms 3 and 4

Both parts of the collimated beam of rays returning to the autocollimator 1 deviate from their original direction. Thus, by means of the gglong mirror mirror 2, the autocollimation images of the mark are constructed. The angular distance between them is determined by the mutual angular deviation of the autocollimation images of the mark in the field of view of the autocollimator 1. For the first

the positions of prisms 3, 4, the angular distance yi between the autocollimation images of the mark is determined by the ratio

45

4 Doi +4 P2 D «2 yi,

where D «1 is the error of the right angle of the prism 3; Dod is the error of the right angle of the prism 4; - the refractive index of the material of the prism 4.

After determining yi, the second prism 4 is moved so that it overlaps the lower part of the collimated beam of rays, and the first prism 3 is installed in place of the second. Now through the prism 3 passes the upper part of the collimated beam of rays of the autocollimator 1, and the lower part of the beam falls directly on the leg of the prism 4. Next, as in the first position of the prisms 3, 4, part of the collimated

beam after reflection from the facet faces of the prism 4 fall on the mirror 2, by means of which, in the reverse direction of the rays, the autocollimating images of the mark are reconstructed and the angular distance yz between them is determined. For the second position of prisms 3, 4 (Fig. 2), the angular distance θ between the autocollimation images of the mark is determined by the ratio

4 u Dat -4 D "2 Hg,

where ni is the refractive index of the material of the prism 3,

Thus, the control of the right angle of the prisms 3, 4 is performed at two positions of each of them according to the position of the autocollimation images of the mark in the field of view of the autocollimator. For both values of y, y2, the angular distance between the autocollimation images, errors of the right angle of both BR-1800 prisms are calculated:

A "Hyi +) / 4 (sp2 + 1), DaNgp U1 - Hg) / 4 (psh2 + 1)

From the expressions it can be seen that using the proposed method with n, 5 it is possible to fix the right angle errors about three times smaller than using the method known from the prototype and, therefore, more precisely. In addition, two prisms of the BR-1800 are monitored simultaneously.

Claims (1)

The invention The method of measuring the right angle of the BR-1800 prisms, which consists of sending the autocollimator radiation to two prisms simultaneously, the first of which is set so that it overlaps the upper part of the collimated beam of rays, the second - on the optical axis of the autocollimator with its base planar reflector make autocollimation images of the mark and determine their position in the field of view of the autocollimator, characterized in that increase the accuracy and performance of the measurement, move the second prism so that it overlaps the lower part of the collimated beam of rays, the first prism is set in place of the second, the autocollimation images of the mark are built again using a flat reflector, and the control is performed at two positions of each of the prisms in position in the field of self-collimation images . tt t. T / FIG. Y // X / UUH // X / L Schi 2