SU61544A1 - Foucault's shadow research light - Google Patents

Description

In many cases of research, it is desirable and even necessary that the luminous bar (slit) and its image be close to the coincidence of the stroke image displacement measured with a particular micrometer, the field of view was not shielded as much as possible, and the stroke image was sufficiently bright.

All devices known to this day do not simultaneously satisfy these four conditions. Thus, in the case of an autocollimation ocular with a prism or with a shadow device by D. D. Maksutov, the image is quite bright, but approximately half the floor is shielded, which makes it difficult to tip. In the case of an autocollimation ocular with a diagonal mirror, we firstly get a double image of the light of the dash line, and secondly, we introduce excessively large losses of light, which does not allow us to use such a device in the study of poorly polished planes and other surfaces. The dividing semi-silvered cube suffers from the lack of a mirror in the sense of light loss and, moreover, often gives a completely unacceptable illumination of the floor from the reflex on its front flat face. Finally, not all devices can automatically achieve a combination of the stroke and its image in the main focus of the lens of the autocollimation tube.

The subject of the invention is an illumination device, free to a large extent from the listed disadvantages. An exemplary embodiment of the invention is shown in FIG. 1-4.

Flat glass

(Fig. I) is made up of two halves with ab face faces polished to the plane; cab angle is slightly more than 45 ° depending on the size of the corner hole of the beam. Both halves of round glass are made of the same low-refractive index glass (for example, C-14 glass). On the ab plane, a mm stroke parallel to the aabb face is silver-plated, after which both halves are glued together with a balm.

A round ef protective glass is glued on top, on the bottom surface of which there is a mesh or crosshair. If the elastic ef is made of heavy or medium flint (for example, C-11 glass), then H1triches of the grid or cross; become visible (like swirls) even without blackening.

In this way, the responsible surfaces of the proposed device are protected from scratching and scratching, and all elements are connected in one transparent disk, which carries brightly colored lines and a weakly lit grid. The stroke appears in the center of the field of view, and its image can be brought into complete coincidence with it. At the same time, the image, its image and the grid can be automatically set at the main focus of the lens of the autocollimation tube, and the entire field is accessible to viewing. The light from the illuminator of a device enters the schtrich mm through the ccdd window.

Instead of gluing with balsam, a method of landing on an optical contact can also be applied. To apply mm shtrikh, we proceed as follows. The surfaces of one of the halves of the bottom glass are protected with mastic; Scratch mm is passed through it, which is then etched with a weak solution of hydrofluoric acid, in order to obtain a depth of Schrich of about a few tenths of a micron and at the same time not make the matt surface of Schrich. After that, when landing on contact at the site of schtrich, total internal reflection will occur. Top glass may be bonded with balsam. You can do without the top glass, applied a grid or crosshairs on the upper surface of the composite glass.

The disadvantage of both options is that, firstly, the image of screech to its width lies in a plane, not perpendicular to the optical axis, which, with a small width of screech, is insignificant and, secondly, the use of such

Illuminator for shadow studies is difficult.

The following option is free from these shortcomings.

Pa figs. 2 shows another possible embodiment of the device. In this case, we will silver both sides of the acute angle of the right half of the composite glass, and then we remove the silver more clearly, so that two strips of ab and a small schiriea remain silver-plated. In this case, the projection of the ab strip should be somewhat larger than ac (taking into account the relative aperture of the beam and to avoid reflex exposure of the floor), and the cd strip should turn black. On the silvered surface, aass conducts a stroke of mm parallel to the edge aa, which lies in the same plane with the luminous slit and is separated from it by a distance of several tenths of a millimeter.

A very small area of zero aadd falls out of observation, with which you can freely make peace.

For all cases, the most rational grid is as follows (Fig. 3). Accepted per unit slot height mm, we draw and weave the grid at different intervals indicated in FIG. 3 so that to the left of the gap is a large enough field of open glass. The rectangle S of such a field will serve for shadow studies. The vertical bar closest to the image of the slit nn will serve to measure the image displacements in the direction perpendicular to the slit length. In this direction, we can give the device a micro-displacement and measure it with great accuracy; otherwise, we will estimate the displacements on the grid, counting the tenth fractions of the intervals between each other. We need horizontal scribbles for counting image displacements in an eye parallel to the slit length. Finally, the entire illuminator, together with the slide and the micrometer screw, can be rotated to a second position, perpendicular to the first (horizontal slit).

If the illuminator is made in the form of a light bulb from a flashlight, directly adjacent to the ccdd face (Fig. 1), then this latter should be made matte. It is much better to introduce an illuminator depicting the hair of a lamp (automobile) on the slit of the TT. In the simplest case, this can be achieved by pasting a flat-convex lens L onto the ccdd face, as shown in FIG. 4. In this. In the case of a composite plate, it is useful to blacken around the rim (cylindrical part).

In the case of the use of diffuse light from a frosted window, it is useful to silver the right half of the cylindrical rim and blacken the left, since the left half can send a reflex beam of parasitic light into the eye of the abyr (Fig. 2).

Subject invention

1. A lighting device for investigating the Foucault shadow method by means of a nols and a light slit, as well as an autocollimation research by means of a light slit and a mesh, characterized in that, in order to eliminate shielding of the field of view, the slit is made in the form of a specularly reflecting sktrikh on the cut surface a plane-parallel plate, either by silvering or by eliminating optical contact at the site of schtrich.

2. The form of the device according to and. 1, characterized in that in order to / protect the surfaces of the parts

1 and 2 plane-parallel plates from mechanical damage; a plane-parallel plate is glued on the latter, the gluing surface of which is provided with a grid.

The form of the device according to paragraphs. 1 and 2, characterized in that the side surface of the part

2 is equipped with a condenser lens glued to it.

FIG. 2