SU1094013A1 - Shadow apparatus - Google Patents

Abstract

A SHADOW INSTALLATION, containing a point source of light installed in series on the optical axis, a collimator, a lens that visualizes a diaphragm located at the focus of the lens, and a recorder that is optically conjugated to the object under investigation, in order to simultaneously register the object in different parts the spectrum of its spatial frequencies, a second recorder optically conjugated with the object under study is introduced into it, the opaque part of the visualizing diach agma contains mirror sections, and its plane The core is equal in angle with the optical axis and the direction to the second recorder. (L © «SO 4 :: oo

Description

The invention relates to optical instrument making, and more specifically to optical devices and devices for researching transparent inhomogeneities. A device is known that uses the method of a light point, in which the subsequent phase inhomogeneity is illuminated by a spherical or flat light wave emanating from a point source C 1. As a result of variations in the refractive index, the light rays passing through different parts of the inhomogeneity deviate by different directions. angles, which leads to a violation of the homogeneity of the original light beam and the redistribution of illumination on the screen. In a first approximation, the relative changes in the illumination of the screen are determined by the second ne of the refractive index integrated over the observation line. For this reason, installations using the luminous point mark are of little use for quantitative measurements of variations in the refractive index. In addition, with installations of this type, inhomogeneities with small refractive index gradients are poorly visualized. Closest to the proposed technical entity is a shadow installation that contains a point source of light installed in series on the optical axis, a collimator, a lens that visualizes the aperture located at the focus of the lens, and a recorder that is optically coupled to the C 2 object under investigation. In this setting, the imaging aperture contains only transparent and opaque areas. In this case, the diaphragm can be made, for example, in the form of a half-plane (knife), which, in the absence of heterogeneity, completely or partially overlaps the image of the light source. The deviation of the rays by the object under study causes a shift in the source image and an increase in the illumination of the corresponding areas of the object image. In this case, the illumination of the screen increases in proportion to the angular deflection of the beam in the direction perpendicular to the edge of the knife. The deflection angle and intensity are proportional to the refractive index gradient integrated over the observation line. Thus, depending on the shape and location of the imaging diaphragm, the object is recorded in any one particular part of its spatial spectrum. This circumstance is a disadvantage of the considered installation, since when studying fast-flowing non-reproducible processes it is necessary to simultaneously register an object in different parts of its spatial spectrum in order to obtain more complete data about it. This is due to the fact that some details are better visualized when the object is registered in the light of the high-frequency component (dark shadow field pattern), and others when the object is registered in the light of the low-frequency component (bright field pattern). The purpose of the invention is to simultaneously register an object in different parts of its spatial frequency spectrum. The goal is achieved by the fact that a point source of light, a collimator, a visualization aperture lens located in the focus of the lens, and a recorder optically conjugated with the object under study are inserted into a shadow system that has a second recorder optically conjugated with the object under investigation. the object, the transparent part of the imaging diaphragm contains mirror sections, and its plane makes equal angles with the optical axis and direction to the second recorder. FIG. Figure 1 shows the optical layout of the proposed installation and the course of the rays in it; in fig. 2-10 are different versions of its visualization diaphragm, where the open sections correspond to the transparent areas of the diaphragm, the black ones to the opaque, and the shaded ones to the mirror. The shadow setup includes a point source 2 of light 2, a collimator 3, a lens 4, a visualizing aperture 5 located in the focus of the lens 4, and a recorder 6, which is optically conjugated with the object under study 7, mounted in series on the optical axis. the recorder 8, also optically conjugated to the object 7. In this case, the non-transparent part of the diaphragm 5 contains mirror sections, and its plane is equal to the optical axis 1 and the direction 9 to the recorder 8 equal angles. The proposed installation works as follows. Light rays that have passed through the phase inhomogeneity under study 7 are deflected by it at different angles, and therefore their spatial frequencies are different. The imaging diaphragm 5 spatially separates radiation streams having different spatial frequencies. In this case, part of the radiation is retained by opaque portions of the diaphragm, part passes through the transparent areas and is directed to the first recording unit 6, and part is reflected from the mirror areas and directed to the second recording unit 8. Depending on the task, the imaging aperture can be performed in different options. Consider the operation of the installation when implementing some of them. An annular mirror knife (Fig. 2) In the forward direction of the rays, a picture is recorded in the low-frequency component of the spatial spectrum, and in the reflected one in the high-frequency component. The frequency separation boundary is determined by the diameter of the hole in the knife. Round. Mirror screen on a transparent layer (Fig. 3). In the forward path of the rays, a pattern is recorded in the high-frequency component of the spatial spectrum, and in the reflected component, in the low-frequency component. The mirror knife is a half-plane with an edge passing through the center of the diaphragm (Fig. 4). In the direct course of the rays, a pattern is recorded at all frequencies and only at positive frequencies Vx. In the reflected course of the rays, the pattern is recorded at all frequencies iJ (and only at negative frequencies., The pattern in the forward direction of the rays and in the reflected will be identical only in the case of a non-uniform network with mirror symmetry. In the absence of such a picture, they will be different. There is no indication of phase non-uniformity symmetry. An opaque plate with round transparent and reflective portions (Fig. 5-7). In this case, in the embodiment shown in Fig. 5, the spatial frequencies v are recorded in the forward path of the rays. , The reflected - frequency l), Vv; 0. And | L) the variant shown in FIG. 6, spatial frequencies are recorded in the forward path of the rays) x; V Oh, in the reflected frequency Vx; Vs, 0. Here Vji - i j ie The identity of pictures in the forward and reflected course of the rays indicates the symmetry of the inhomogeneity at the frequency. In the embodiment shown in FIG. 7, spatial frequencies -Jjf are recorded in the forward path of the rays, while in the reflected VY ,. At the same time | VxJ. An opaque plate with mutually perpendicular transparent and specular stripes (Fig. 8 and 9). In the embodiment shown in FIG. 8, an image is recorded in forward motion at spatial frequencies O (without limiting the spectrum l) y), and reflected in the image - Vx (without limiting the spectrum)). The variant shown in Fig. 9 is similar to the previous one, but with registration not at zero frequency V (. In the embodiment shown in Fig. 10, the pictures recorded in direct and reflected light will be the same if the heterogeneity under study has central symmetry. Otherwise, the pictures will be different. It should be noted that when implementing the Proposed installation it is possible to simultaneously dual-channel registration in two spectral ranges (due to the introduction of spectrally selective filters or nanoscopes into the channels) The number of spectral selective coatings on the imaging diaphragm.) It is also possible to use a phase shift when reflecting from specular areas, thus introducing a phase contrast into the reflected pattern. 1 In addition, changing the law of change of reflectance (transmittance, absorption) with coordinates, you can get D of other effects, in particular - 5,: the appraisal of the shadow pattern in - both% ajalah. Taj po6pa30Mf the proposed device®) compared to the known one provides simultaneous registration of the shadow image of an object in its parts, it is easy to see cnjEKTpa without illumination. 3 Depending on the shape and location of the transparent, opaque and mirror areas of the visualizing a diaphragm device allows to reveal the symmetry of heterogeneity, produce apodization of the shadow pattern in both channels, register the shadow pattern in different spectral ranges, etc.

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Claims (1)

SHADOW INSTALLATION, containing a point light source mounted in series on the optical axis, a collimator, a lens that visualizes the diaphragm located in the focus of the lens, and a registrar optically coupled to the object under study, characterized in that, in order to simultaneously register the object in different parts of its spatial spectrum frequencies, a second recorder is introduced into it, optically conjugated to the object under study, the opaque part of the visualizing diaphragm contains mirror sections, and its plane sets with the optical axis and direction to the second recorder equal Figure 1