SU1125592A1 - Optical system for producing intermediate image in application of contrasting techniques in microscopes - Google Patents

Abstract

1. OPTICAL SYSTEM FOR THE INTERMEDIATE IMAGE IN THE IMPLEMENTATION OF CONTRAST METHODS IN MICROSCOPES, containing a capacitor, polarizer, lens for obtaining an intermediate image of the object, the analyzer, optical components, matching the exit pupil and the polarization optical element to the perspective of the perspective of the projected piece. pupil, characterized in that, in order to reduce its dimensions while maintaining the orthogonality of the polarized beams of rays, at least three deviations are introduced into it guides prism disposed between the output lens pupil and the intermediate image, a refractive index n which is the angle of incidence V .i bonded soeU 1 ratio; RU; | L where JM is the number of prisms. 2. The system according to claim 1., about tl and - / L, so that a polarization-optical half-wave plate is inserted between the exit pupil of the lens and its intermediate image.

Description

The invention is used to contrast in a phase contrast or in contrast an interference pattern de polarized with light, organic or inorganic objects that do not absorb in transmitted light and have a reflectance equal to the environment in incident light. The system mainly serves as an additional device in conjunction with the phase contrast or contrast devices of the interference pattern for microscopes selected for this purpose for observation in transmitted or reflected light, but it can also be an essential part of the microscope. At the same time, for example, for phase contrast there is no need for special phase-contrast lenses, and the necessary annular phase plates can be located on the image of the pupil of the objective created by part of the intermediate image system. At the same place you can insert optical contrast interference pattern of Wollaston prism. Thus, a quick change between the two types of contrast is possible. The invention is primarily used in biology and medicine, however, and in technical fields, such as chemistry and metallography, for contrasting phase objects. These are microscopic objects that are not contrasted at all or are only slightly contrasted during normal observation in a bright field. A known intermediate image system that fulfills the condition of maintaining linear polarization by providing a requirement; that the intermediate image of the pupil of the lens is obtained even before the first reflecting element (for example, Austrian patent No. 313222, class 42 h 12/01, -1974). This proposal is not beneficial in a constructive respect, since with a feasible correction cost, a certain minimum length is needed, which either leads to an unacceptable viewing height or, as presented in the example, requires an expensive and structurally unsuitable deflecting system back to the microscope tube, located at a normal viewing height. A well-known optical system for obtaining an intermediate image in the process of contrasting methods in microscopes, containing a condenser, a polarizer, a lens for obtaining an intermediate image of an object, an analyzer, optical components, matching output pupil and a polarization-optical element located in the intermediate plane. images of the exit pupil (economic patent GDR No. 53890, cl. 42h, 38, 1967 rj. The purpose of the invention is to create a device that, when using light-field lenses, normal or large fields and high quality images of phase contrast and polarization-optical interference - contrast fast switching of one type of observation to another, as is desirable for many microscopic studies, in particular, living objects; and having reduced dimensions while maintaining orthogonality polarized beams of light. The object of the invention is to create an intermediate image system for the implementation of contrast in microscopes in pr-1enenii light-field volume Ticks for normal or large fields, which are introduced into the beam path and using reflective elements and projection optics, create available intermediate images of the plane of the object and the pupil of the lens. In this case, the reflecting elements are arranged and matched with each other in such a way that the light linearly polarized in the pupil of the lens in the first-slit image of the pupil of the lens is again obtained as linearly polarized light. This corresponds to the polarization conditions required for polarization. - optic of the image of the interference contrast, in which it is important to decompose} the right-handed polarized light falling on the Wollaston prism, consists of a double copying material and is located in the space of This, on the ordinary and extraordinary components, oscillating perpendicularly one another and linearly polarized. Both components, which are shifted to the side by an insignificant amount, emerge from Wollaston's prism. In the latter, located in the image plane and in the image or in the vicinity of the image of the pupil of the lens and thus within the system of the intermediate image, both components are again combined into one beam. However, this will only be the case if the Wollaston prism located on the side of the image is produced as linearly polarized light. It is known from theoretical optics that with full internal reflection on the glass surface between the components of the beams, oscillating parallel and perpendicular to the plane of incidence i, there is a dependence on the angle of incidence V and the refractive index of the inclination of glass h

f

C05V

There is a relationship AH-

& 2

V for an axial beam with a deflection of 90 ° is 45. So with 1L N3,

rsl

About 60, so that after a threefold reflection, the phase difference is 180, and the resultant of both components of the rays oscillates in the same plane as the strip, i.e., it is linearly polarized. A similar effect is achieved with the help of four prisms, if (review of the circumstances of K V) changes so that 8 D5 °.

If the direction of oscillation of the component rays by turning on the polarization-optical plate rotates by 90, for example, due to the rotation of the plane of incidence from one to the next prism, an ordinary beam on the reflecting surface on the next surface turns into an unusual one, and the unusual beam turns into an ordinary one, and therefore, the phase difference resulting from these two reflections is zero. With the aid of the plate / 2 it is reached, as in

where N is the number of prisms,

The drawing shows a diagram of the device

The beam of light 1 from the light source is linearly polarized by the polarizer 2 oriented

under 45 relative to the spaced object of Wollaston's prism 3 and it decomposes into ordinary and extraordinary components, oscillating perpendicular

one another.

After passing through the condenser 4, both partial beams, laterally displaced by an insignificant amount, pass through the plane

Item 5, lens 6 and pupil

lens 7, indicated by a crosshair, and reflected on the surface 9, completely covered with a mirror layer, of a glass cube 8 consisting of /

of the two glued rectangular prisms. As components of the light flux with different directions of oscillations fall on the surface 9 perpendicularly or parallel to the plane of incidence, linear polarization for both components is preserved.

On prisms 10, 13 and 14, consisting of 3 glasses with an approximate figure 592 4 of this part, the ordinary beam remains ordinary and the unusual beam remains extraordinary. Since the reflecting rays incident on the prism planes have a slightly different inclination and therefore reach the reflecting surfaces at different angles of incidence V, the phase difference is not the same for all the rays and for off-axis rays it should be considered with a slight ellipticity of polarized light, which in the extreme case is not more than 1% and in practice almost does not interfere. Since the apertures of the angles of the imaging light beams on different surfaces are generally different, in addition, prisms with different refractive indices can be optimized, In the general case, the refractive index of prisms and the angle of incidence V are related by the ratio η cosV; - | 5iiri Vr X a ctg- 7 5

refracted, both partial beams undergo total internal reflection. Between the components of each partial beam, oscillating in parallel and perpendicular to the plane of incidence, there is a phase difference S 60 °, so that on the prism 10, elliptical polarized light is obtained from linearly polarized light. Since the same process is on prisms 13 and 14, the named phase difference accumulates on the image of the pupil 16, indicated by a cross, and created by a lens system 11, it is 180, so that there is again a linear-polarized light,

Wollaston prism 15, located in the image plane, subsequently includes two partial beams, laterally displaced by a small amount, oscillating perpendicularly to one another and generally having a slight phase difference, which in a spatially connected state emerges from the prism.

The analyzer 17, oriented perpendicularly or parallel to the polarizer 2, passes only components of both oscillating in its direction perpendicularly one to another of the circular sections of partial beams that interfere with each other. An intermediate image 12 of an object 5 located in the plane of an object 5 created by the lens 6 and the lens system 11, into which for the purposes of measurement plates can be inserted with a grid of strokes or other markings, the lens system 18 through the prism 19 and the surface 9 completely covered with a mirror layer is contrasted with field diaphragm (not shown) ocular located in direction 20 The refractive index of prism 19 is insignificant. The prism 19 can be replaced with another surface covered with a mirror layer.

A further example of a specific embodiment relates to the possibilities of using four total internal reflections and glass prisms of a lower refractive index. The device corresponds to the device shown in the drawing, however, they replace the surface 9 completely covered with a mirror layer, a thin layer of air of 0.01 mm and a prism with total internal reflection of 8, 10, 13 and 14 prisms made of glass of refractive index C 1,554, In this case on each surface, when the angle of incidence V 45 45 is obtained, the phase difference b is -45 °. Since the planes of incidence of the reflecting surfaces of prisms 9 and 10 are rotated, the ordinary component turns into an extraordinary one and vice versa, so that phase differences are mutually destroyed. This difficulty can be eliminated by introducing the polarization-optical plate / 2 21, since it rotates the direction of vibrations by 90 ". so that the phase differences arising from the reflection on the four prisms mentioned are added, and the linear-polarized light is again obtained in the image of the pupil.

By varying the device of reflective elements and building images, further variations are possible. In particular, various refractive indices of prisms with total internal reflection can be optimized with respect to the aperture angles of the imaging beams that change from a prism to a prism.

Claims (2)

1. OPTICAL SYSTEM FOR OBTAINING INTERMEDIATE IMAGE WHEN IMPLEMENTING CONTRAST METHODS IN MICROSCOPES, containing a capacitor, a polarizer, a lens for obtaining an intermediate image of an object, an analyzer, optical components that interface the exit pupil and the polarization-optical image that is located in the fact that, in order to reduce its size while maintaining the orthogonality of the polarized beam of rays, at least three openings are introduced into it dropping prisms located between the exit pupil of the lens and its intermediate image, the refractive index η of which and the angle of incidence V are related by the relation where is the number of prisms. 2. The system by π. 1, characterized in that between the exit pupil of the lens and its intermediate image introduced polarization-optical half-wave plate.