SU1283576A1 - Device for angular measuring of beam position - Google Patents

Abstract

The invention relates to optical systems and can be used in projection type display devices. The purpose of the invention is to reduce the loss of light energy and to increase the accuracy of measuring the position of the light

Description

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Boro. The device contains a successive light source 1, aperture 2, a deflecting mirror 3 connected with an electromechanical actuator 4, which in turn is connected with a control unit 5. A prism cube 7 is mounted between the focusing 6 and 9 measuring lenses, two-dimensional diffraction grating 8, made of the condition of equality of the distribution of light energy in the zero and first orders of diffraction, and a block of 10 photodetectors in the form of a four-square receiver Diaphragmized light beam after deflection its mirror 3 and fokusi1

The invention relates to optical systems and can be used in projection type display devices, as well as scan type scanners.

The purpose of the invention is to reduce the loss of light energy and improve the accuracy of measuring the position of the working light beam in space.

Fig. 1 shows a block diagram of a device for angularly measuring the position of a beam; Fig. 2 shows an interference pattern in the plane of placement of photodetectors.

The device contains a source of light 1, aperture 2, a mirror 3, an electromechanical actuator 4, a control unit 5, the first lens 6, a light cube-prism 7, a two-dimensional diffraction grating 8, a second lens 9, a unit of 10 photodetectors.

The device works as follows. The light beam from the light source 1 is guided through the apertures of the diaphragm 2 to the mirror 3, which is controlled by an electromechanical drive 4. Between the first lens 6 and the two-dimensional diffraction grating 8 there is a beam-splitting prism-cube 7, which 90% of the light energy deflects in the working direction and 10% in the direction of measurement. Measuring part of the light beam

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The lens 6 is divided by the prism-cube 7 into the working and measuring rays. The measuring beam is focused on a two-dimensional diffraction grating 8, after which the interference pattern of zero and first diffraction portions partially aligned in space with the help of a measuring lens 9 is directed to a block of photodetectors 10, which produce measuring signals proportional to the movement of the light beam along two coordinates. Using these signals, the control unit 5 controls the position of the deflecting mirror 3. 2 Il.

is focused by the first lens 6 on the two-dimensional diffraction grating 8 and after passing it is divided into five rays corresponding to the zero and first diffraction orders on the orthogonal strokes of the grating 8. With the help of the second objective 9, the divergent rays are converted into pairs. parallel and directed to a block of 10 photodetectors. In order to obtain an interference pattern in the plane of the photodetectors. 2) the diameter of the opening of the diaphragm must be within

.D.-2-i,

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where D is the diameter of the hole in the diaphragm, m;

f is the focal distance of the focusing lens, m; Z is the period of a two-dimensional diffraction grating, m; - Dpina waves of light, m. ye. In real devices, the size of the opening of the diaphragm 2 is in the range of 6-30 mm.

The distances between the second lens 9, the mirror 3, the two-dimensional diffraction grating 8 and the plane of location photg) of the receivers of the photoreceiver unit 10 are chosen so that the center of the interference pattern does not shift when the light beam deflects, but only

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Claims (1)

Invention Formula The device gave an angular measurement of the position of the beam, containing successively placed E-source of light, a diaphragm, a mirror mounted rotatably and connected to an electromechanical drive, a first lens, a two-dimensional diffraction grating, a second lens, photodetectors and a control unit electrically connected to photodetectors and electromechanical drive 0 76 i-cM house that, in order to reduce the loss of light energy and increase accuracy, three photodetectors are added to the device, placed in the same plane and forming a four-square receiver with the first receiver, and the two-dimensional diffraction grating is made from the condition of equal distribution of light energy in zero and first orders of diffraction, and the diameter of the diaphragm satisfies the condition f 2fj , uh i D -z where D is the diameter of the hole in the diaphragm, m; f is the focal distance of the lens of the first, m; Z is the period of a two-dimensional diffraction grating, m;  X - light wavelength, m The compiler. S.Oreshin Editor L.Povkhan Tekhred L.Serdyukova Proofreader L.Pilipeiko Order 7428/38 Circulation 776 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, ul. Project, 4 FIA.2