SU934549A1 - Device for optical recording-reprodcuing on translucent carrier - Google Patents

Description

one

The invention relates to an information storage technique, namely, optical recording-reproducing devices on a semi-transparent medium using means for correcting the relative position of the light source and the carrier.

An optical recording device is known that contains a laser light source, a lens, a main-channel photoreceiver, a lens displacement unit and a control unit made with an additional optical system and photodetectors, the outputs of which are connected to the input 1 of the control unit, and the output of the latter is connected to the lens displacement unit. the optical system and additional photodetectors complicate the known device.

It is also known a device comprising a carrier drive, a laser light source, an optical system with a photodetector and an objective, a node.

lens, filter and phase detector, one input of which is connected to the source of the Keny reference, another input is connected through the filter to the photodetector output, and the output is connected to the input of the lens 2J moving unit.

The disadvantage of the described device is reduced noise immunity, due to the fact that for

10 to ensure the operation of the phase detector, the reference signal is recorded in the main signal channel.

The purpose of the invention is to improve noise immunity.

15

This goal is achieved by the fact that the device is equipped with a modulator, which is made in the form of raster stripes oriented perpendicular to the direction of rotation of the carrier, with

In this case, the modulator is mounted on the drive shaft under a translucent carrier.

Claims (2)

Figure 1 shows the blSG-diagram of the device; figure 2 - the course of the rays through the video plate; 3-5, the modulation of the beam in a raster modulator depending on the position of the lens; figure 6 is a variant of the device with a cylindrical carrier; Fig.7 modulator device with a cylindrical carrier. The device contains a laser light source 1, a lens 2, mirrors 3-5, a lens 6 mounted in a displacement unit (not shown), a semi-transverse carrier 7 mounted on a drive shaft 8, a lens 9, a photo-receiver 10, an amplifier 11, filters 12 and , 13 shaper H signals, phase detector 15, reference oscillator 1b and power amplifier 17, the output of which is connected to the input of the lens moving unit 6. The raster modulator is made in the form of strips 18, which are placed under the translucent carrier 7 and are oriented perpendicular to the direction of rotation of the carrier 7. The modulator in the form of strips 18 can be applied to the reverse side of the carrier 7. The device operates as follows I. Beam from a laser source 1 through lens 2 hits mirrors 3-5 and reflected from the last mirror is focused by lens 6 onto the surface of carrier 7 where it is modulated with recorded information. A part of which passes through the translucent carrier 7 to the raster modulator. Reflected from the surface of the carrier and strips 18 of the raster modulator of the beam enter the lens 6, and then, reflecting from the mirrors 5, and 3, are focused by a lens 9 onto the surface of the photo-receiver 10, where they are converted into an electrical signal (Fig. 3 and 5) . The spectrum of the signal recorded on the carrier 7 is extracted by the filter 13. The composite signal modulated by the raster module strip 18 is extracted by the filter 12 (the signal on the output of the filter 12 for three values of the diameter of the focused spot on the figure) and after the former R | applied to one of the inputs of the phase detector 15, to the other input. which provides the reference signal from the generator 16. The voltage from the output of the phase detector 15 through the amplifier 17 moves the lens 6, which ensures the focusing of the beam of the laser source 1 on the surface of the carrier 7. Figure 6 shows an optical recording-reproducing device with a cylindrical carrier 7 fixed on supports 19 and 20 rotations. A raster modulator in such a device is implemented in the form of parallel bands 18. The invention makes it possible to increase noise immunity in a device with a single optical system and a single photoreceiver (main channel strength. The optical recording-reproduction device on a semi-transparent medium containing a carrier drive, a laser light source , optical system with a photodetector and a lens, a lens displacement unit, a filter and a phase detector, one input of which is connected to a source of reference voltage, the other in d is connected through a filter to the photodetector output, and the output is connected to the input of the lens displacement unit, differently in that it is equipped with a modulator in the form of raster stripes oriented perpendicular to the direction of rotation of the carriers, while the module The torus is fixed on the drive shaft under a translucent carrier. Sources of information taken into account during the examination 1. US patent number 3997715, cl. 178-6.6, published. 1976. 2. Japanese Patent No, cl. 102 D 5, published 1979 (prototype). Fog.2 fS fug. V S 7 7d I I f1 / g. 7 fg / g: &