SU1522281A1 - Apparatus for optical playback of information from magnetic record carrier - Google Patents

Abstract

The invention relates to the accumulation of information and can be used in devices for reproducing information from a magnetic recording medium by optical means. The purpose of the invention is to expand the range of information signals reproduced by the device. The laser radiation 1 is introduced into the input ends of the supply single-mode fiber 2 of the optical signal generating unit, which also contains the output multimode fiber 3. The optical fibers 2 and 3 are mounted on the plane of the ferrite-garnet film 4 and form with it the angle α determined from the ratio α≤90 ° - [ARCSIN (1 / N _C ) + ARCSIN (NA / N _C )], where NA is the numerical aperture of optical fibers

N _C is the refractive index of the core of the optical fibers. On the other plane of the film 4, a layer 5 of a light-absorbing material is deposited, in which a slit 6 is formed. The information is reproduced by a photodetector unit, including polaroid 8 and a photodetector 9. 2 Il.

Description

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1522281

The invention relates to the accumulation of information and can be used in devices for reproducing information from magnetic recording media by optical means.

The purpose of the invention is to expand the range of reproducible informational device, alope.

FIG. 1 shows a device, a general view of FIG. 2 shows the optical layout of the device.

The device comprises a laser 1, an optical signal forming unit consisting of supplying single-mode optical fibers 2, diverting multi-mode optical fibers 3, a ferrite-garnet film 4 and a layer 5 of light-absorbing material with a slit 6, a magnetic recording carrier 7 and a photodetector a block comprising a polaroid 8 and a photodetector 9.

. The device works as follows.

The light flux from laser 1 is directed to the input ends of the supplying single-mode optical fibers 2 of the optical signal generation unit and, coming out of the end-ends, forms a reproducing light beam that falls on the working surface of the ferrite-garnet film 4. A part of the reproducing beam falling on a layer 5 of a light absorbing material located on a ferrite-garnet film is absorbed by the material of this layer. Another part of the beam, after reflection from the working surface of the ferrite-garnet ploy and 4 in the region of the slit 6, forms an informational

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acquires a rotation of the radiation polarization plane due to the dual Farad effect. The magnitude of this rotation depends on the amplitude of the recorded information signal on the magnetic recording medium 7. Next, the information light, passing through the polaroid 8 of the photoreceiver unit, is modulated in amplitude and hits the photodetector 9, from which an information signal is taken that is proportional to the scattering field of the magnetic carrier records 7 in the area of the slit 6, the width of which can be increased to 5 mm. Depending on the type of signal recorded on the magnetic recording medium 7, the electrical signal from the photodetector 9 can be transmitted to any actuator.

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 the invention

A device for optical reproduction of information from a magnetic recording medium, comprising a laser, an optical signal generating unit and a photoreceiver unit, characterized in that, in order to expand the range of information signals reproduced by the device, the optical signal generating unit is designed as optically coupled single-mode and outgoing multimode fibers and a ferrite-garnet film, the input ends of the lead 1x and the output ends of the output fibers, respectively, optically coupled with a laser and a photo-light beam and enters the discharge unit, a layer of light-absorbing material with a slit is deposited on one plane of the ferrite-garnet film and on the other plane the output ends of the supplying single-mode and input ends of the outgoing multimode light guides are made rulers parallel to the slit and these ends form an angle of rotation with the plane of the ferrite-garnet film, determined from the relation:

multimode light guide 3.

The ends of both optical fibers 2 and 3 are mounted at an angle ci to the surface of the ferrite-garnet film 4. It is determined from the ratio

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l H x1 h / MAL 9Сг - arcsin (-) i-arcsin (-) 1 L с с J

where NA is the numerical aperture of optical fibers}

n is the refractive index of the core of the optical fibers.

Information luminous flux twice passed through the thickness of magnetized ferrite-garnet film 4

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acquires a rotational plane of the polarization of the radiation due to the dual Farad effect. The magnitude of this rotation depends on the amplitude of the recorded information signal on the magnetic recording medium 7. Next, the information light, passing through the polaroid 8 of the photoreceiver unit, is modulated in amplitude and hits the photodetector 9, from which an information signal is taken that is proportional to the scattering field of the magnetic carrier records 7 in the area of the slit 6, the width of which can be increased to 5 mm. Depending on the type of signal recorded on the magnetic recording medium 7, the electrical signal from the photodetector 9 can be transmitted to any actuator.

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 the invention

A device for optical reproduction of information from a magnetic recording carrier, comprising a laser, an optical signal generating unit and a photoreceiver unit, characterized in that, in order to expand the range of information signals reproduced by the device, the optical signal generating unit is designed as optically interconnected single-mode supply outgoing multimode light guides and ferrite-garnet film, the input ends of the lead 1x and the output ends of the output fibers, respectively, optically coupled to with a laser and a photodetector unit, on one plane

The rhythm-garnet film has a layer of light-absorbing material with a slit, and on the other plane the output ends of the supply single-mode and input ends of the outgoing multimode light guides are installed, made in the form of lines parallel to the slit, and these ends make up the ferrite plane - garnet film angle, determined from the relation:

e (- 90 ° - Gagszp (-) - (- arcsin (-), L. t t J

where NA is the numerical aperture of the optical fibers; n is the refractive index of the core of the optical fibers.

Claims (1)

Claim A device for optical reproduction of information from a magnetic recording medium containing a laser, an optical signal generating unit and a photodetector unit, characterized in that, in order to expand the range of information signals reproduced by the device, the optical signal generating unit is made in the form of optically coupled single-mode input and output multimode optical fibers and a garnet-ferrite film, the input ends of the input and output ends of the output optical fibers, respectively, are optically coupled with a laser and a photodetector, a layer of a light-absorbing material with a slit is deposited on one plane of a garnet-garnet film, and on the other plane, the output ends of the supply single-mode and input ends of the output multimode optical fibers are made in the form of rulers parallel to the gap, and these ends comprise with the plane of the ferrite garnet film, the angle r, determined from the ratio: „„ About G. ζ 1 · x / L ON eC <90 -arcsin (-) + arcsin (- ), L n t n o J where NA - numerical aperture optical fibers; n _c is the refractive index of the core of the optical fibers. Compiled by S. Ilchuk Editor M.Tovtii Tehred M. Khodanich Corrector 0. Kravtsova Order 6970/50 Circulation 558 Subscription VNIIIPI State 113035, Committee for Inventions and Discoveries under the USSR SCST Moscow, Zh-35, Raushskaya nab., D. 4/5 Production and Publishing Plant Patent ’', Uzhhorod, st. Gagarina, 101