RU2254601C2 - Three-mirror system - Google Patents

Abstract

FIELD: optical engineering.

SUBSTANCE: three-mirror system can be used for deflecting optical beam in space to keep to constant angle. System has three optical elements with reflecting surfaces and common base onto which those reflecting surfaces are supposed and fastened rigidly. Two optical elements, which form dihedral angle with common rib, have reflecting and polished surfaces and are made in form of two plates joined together; one plate has rectangular shape. Polished surfaces are tied rigidly together and reflecting surfaces form exact 90º angle and have similar sizes. Third element has reflecting surface which forms 90º angle with rib of dihedral angle. The third element is fixed at common base in such a way that its reflecting surface directs light beam in parallel to entrance beam but in opposite direction.

EFFECT: high degree of parallelism of entrance and exit beams.

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Description

The invention relates to optical instrumentation, and in particular to high-precision optical devices designed to deflect an optical beam in space with a constant angle, and can be used to check the parallelism of two axes of multichannel optical devices, including those designed to operate in the infrared region of the spectrum.

The known prism BKR-180 (Kruger M.Ya. et al. "Designer Handbook of Optical-Mechanical Devices", Moscow, Mashgiz, 1963, p. 261), which is a system of three mirrors (MM Rusinov, "Adjustment of Optical instruments ”, Moscow, 1969, pp. 146-148), consisting of two flat mirrors, the reflective surfaces of which form a straight dihedral angle with a common edge, and a third mirror, the reflective surface of which is 90 degrees to the edge dihedral angle. The accuracy of parallelism of the input and output rays depends on the accuracy of manufacturing the dihedral angle and the position of the reflective surface of the third mirror. In this case, such accuracy is achieved by constructively performing the dihedral angle and the reflective surface of the third mirror in one monolithic piece of optical material. All three optical elements here are rigidly interconnected. The input beam directed from the dihedral angle is reflected by the third mirror in the opposite direction parallel to the input beam. Such a system has a constant deviation angle in two mutually perpendicular planes with a return path of reflected rays.

Its disadvantage is that the optical material of the prism BKR-180 (glass grade) depends on its use in a specific region of the spectrum. So, when using the prism BKR-180 in the infrared region of the spectrum, barium fluoride (toxic during processing) or germanium (very expensive) is used as an optical material.

This disadvantage is eliminated in the well-known two-channel optical system according to the international application WO 9507490 (G 02 B 23/02, priority US 94101115 from 09/08/94), which allows the use of relatively inexpensive reflectors and adopted as a prototype. Each channel is a system of three mirrors in which an air gap is located between all reflective surfaces, which makes it possible to use such a system in any region of the spectrum. Reflectors are a set of flat mirrors, two of which have main sections located in two mutually perpendicular planes and form a straight dihedral angle with a common edge, and the third flat mirror has a reflective surface located at an angle of 90 degrees to the common edge of the dihedral angle . Such a system is simple to manufacture.

The disadvantage of the prototype is the low accuracy of parallelism of the input and output beam, due to lower requirements for the accuracy of alignment of mirrors compared to traditional systems based on optical prisms, because, in this case, the mirrors are located on different bases, separately from each other (there is no rigid connections between the elements) are separately mounted and adjusted. In addition, misalignment of the system during operation is possible, which generally reduces the possibility of its use in precision measuring optical instruments.

The problem to which this invention is directed is to create an inexpensive optical system that provides high accuracy of parallelism of the input and output beam of rays relative to each other in two mutually perpendicular planes for any region of the spectrum.

The problem is achieved in that the system of three mirrors consists of two optical elements with reflective surfaces, which have major sections located in two mutually perpendicular planes, and form a straight dihedral angle with a common edge, and an optical element with a reflective surface, which is angle of 90 degrees with respect to the edge of the dihedral angle. In this case, an air gap is located between the reflective surfaces of the optical elements.

This technical solution differs from the prototype in that all optical elements are located on a flat surface of a common base and are rigidly connected with it, and two optical elements forming a right dihedral angle with a common edge are made in the form of a connection of two plates, one of which is rectangular, having reflective and polished surfaces so that the polished surfaces are rigidly interconnected, and the reflective surfaces form an exact right angle and have the same dimensions, with the third optical element the ment is fixed on a common basis so that its reflective surface directs the beam of rays parallel to the input, but in the opposite direction.

Two optical elements with reflective surfaces, which form a straight dihedral angle with a common edge between them, unfold the input beam of rays 90 degrees in two mutually perpendicular planes.

The third optical element with a reflective surface, which makes an angle of 90 degrees with respect to the edge of the dihedral angle, allows you to deflect the beam of rays by another 90 degrees and, thereby, deploy the incoming beam in the opposite direction.

The exact right angle between the two optical elements is ensured by the position of the reflective surfaces of two plates connected by polished surfaces, one of which is rectangular.

The accuracy of the location of the reflective surface of the third optical element in space is ensured by its rigid connection with all elements of the system.

The identical dimensions of the reflective surfaces of two rectangular plates ensure the passage of a full light beam of rays without cutting it off.

The air gap located between the reflective surfaces of the optical elements allows you to use the system with inexpensive optical material in any region of the spectrum, including in infrared.

The location of the optical elements on a flat surface of a common base and the rigid connection of all elements with each other ensure the invariability of the position of the optical rays in space. There is no need for additional adjustment of the system during operation.

Such a system has a simplicity of design and manufacturability.

The invention is presented in figures 1-3.

Figure 1 shows a General view of a system of three mirrors.

Figure 2 shows a view A of a system of three mirrors.

Figure 3 shows a cross-section GG system of three mirrors.

The system consists of a base 1 (FIG. 1) having a flat surface 2 on which are rigidly fixed: an optical element 3 having a reflective surface 4 (FIG. 2) and a polished surface 5 (FIG. 3), an optical element 6 (FIG. 2) having a polished surface 7 with a reflective portion 8 equal in size to the reflective surface 4 of the optical element 3, and an optical element 9 (FIG. 1) having a flat surface 10 and a reflective surface 11 (FIG. 2). Reflective surfaces 4 and 8 form a straight dihedral angle with a common edge 12 (figure 3).

The optical element 3 (Fig. 3) is made in the form of a rectangular plate, the reflective surface 4 of which is perpendicular to the polished surface 5. The polished surface 7 of the optical element 6 is rigidly connected to the polished surface 5 of the element 3. Moreover, it is formed by the reflective surface 4 and the reflective portion 8 of the straight line the dihedral angle is made with high accuracy, ensured by the accuracy of the manufacture of optical elements and their rigid connection with each other, which is easily feasible.

The principle of operation of the three mirror system is as follows.

The input light beam of rays falls on the reflective surfaces 4 and 8 of the optical elements 3 and 6, respectively (FIG. 1, FIG. 2), is deflected by 90 degrees by these surfaces, the air gap passes and enters the precisely installed mirror surface 11 of element 9. Then the beam rays is reflected from this surface, with a repeated turn of 90 degrees and goes parallel to the input beam of rays, but in the opposite direction (figure 1). Moreover, the output beam always remains parallel to the input beam, regardless of the change in position in the space of the specified system.

Claims (1)

A system of three mirrors consisting of two optical elements with reflective surfaces that form a straight dihedral angle with a common edge, and an optical element with a reflective surface that makes an angle of 90 degrees relative to the edge of the dihedral angle so that between the reflective surfaces of the optical elements there is an air gap, characterized in that all the optical elements are located on a flat surface of a common base and are rigidly connected with it, moreover, two optical elements, o forming a right dihedral angle with a common edge, made in the form of a connection of two plates, one of which is rectangular, having reflective and polished surfaces so that the polished surfaces are rigidly connected to each other, and the reflective surfaces form an exact right angle and have the same dimensions, while the third the optical element is mounted on a common basis so that its reflective surface directs the beam of rays parallel to the input, but in the opposite direction.

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