SU1224826A1 - Device for reproducing information from optical medium - Google Patents

Abstract

The invention can be used in video and audio laser players and can reduce the loss of light energy. The device contains a three-beam splitter 2 of the beam, spinning in the form of a prism-wedge, on the front face of which there are two reflective and one enlightened zones, and the rear face is made completely reflective. Due to the fact that the reflective zones have different reflection coefficients, the radiation from source 1 is split into three beams of rays for tracking the information track and for reproducing information. Passing through the matching lens 3, the beam splitter 4 and the quarter-wave plate 5, the rays 6 are directed by the mirror 6 into the lens 7, which forms reproducing and following the track on the information carrier 8. From the central receiver of the photodetector unit 9, the information signal is removed, and from the side, error signals tracking the information track, which, after conversion, are fed to the drive input of the mirror 6 for positioning the beam of rays relative to the information track. 1 il.

Description

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The invention relates to the reproduction of information by means and tools and can be used in video and audio laser players.

The aim of the invention is to reduce the loss of light energy

The drawing shows the optical layout of the device.

The device contains a source of radiation 1, a three-beam beam splitter, a matching lens 3, a beam splitter 4, a quarter-wave plate 5, a displacement driven mirror 6 (not shown), a lens 7, a carrier 8 of information and a photo-receiving unit 9.

The device works in the following way.

The radiation of the radiation source 1 is directed to the zone a of the three-beam splitter 2 of the beam. Zone a has a reflection coefficient p, and reflects part of the radiation in the direction of the matching lens 3. The reflected part of the radiation passes into the substrate of the three-beam splitter 2 of the beam and is reflected from the fully reflecting rear face to the area b of the front face having the reflection coefficient

p -P2-, p,

Most of the radiation

passes zone 6 and is directed to matching lens 3, and the reflected part of the radiation is again reflected from the rear face and also directed to matching lens 3, the passage through the illuminated zone c. The reflection coefficient p is such that the beams passing through the zones o and c have power, for example, 17%, and the zone c is 66% of the power of the radiation source 1 and form beam beams for tracking the information track and for reproducing information, respectively. This design of the three-beam splitter 2 of the beam makes it possible to minimize the light loss on it.

Three beams of rays successively pass a matching lens 3, a beam splitter 4 and a quarter-wave plate 5, and then are reflected by a mirror 6

into the lens 7, which forms reproducing and tracing spots on the carrier 8, reflecting from which the beams of rays again pass the lens, mirror, quarter-wave plate and are guided by the beam splitter 4 to the photo-receiver unit 9 consisting of three photo-receivers. An information signal is removed from the central photodetector, and side error signals are followed by the information track, which are converted by an electronic system (not shown) into the mirror 6 position control signals and fed to the input of its drive (not shown) for positioning the beam beams relative to the information track.

Claims (1)

Invention Formula A device for reproducing information from an optical medium containing optically coupled and sequentially mounted source radiation, a three-beam beam splitter, a matching lens, a beam splitter, a quarter-wave plate, a displacement drive mirror and a lens, as well as an optical receiving unit, the output of which is connected to the drive input of the displacement mirror, characterized in that, to reduce losses light energy, the three-beam beam splitter is made in the form of a prism wedge, on the front face of which there are two reflected and one lightened zones, while the first reflective zone is made with coefficients The reflection factor (5,, second - / g / D,, where /) is the ratio of the radiation power reflected by the zone to the radiation power of the radiation source, and the rear face of the prism is completely reflective.