SU1571666A1 - Device for recording and reproducing information from reflecting optical carrier - Google Patents

Abstract

The invention relates to the accumulation of information by optical means and can be used in computing. The aim of the invention is to increase the reliability of recording and reproducing information in real time. The radiation of the radiation source 1 is reflected by a polarization beam splitter 2 towards the element 4 with a variable focal length, the quarter-wave plate 3 passes in the forward path, which passes for the second time after reflection from the element 4. In the reverse run, the beam splitter 2 passes the radiation with almost no reflection, then an additional quarter-wave plate 5 and is focused by the lens 6 on the carrier 7 of information. In the reverse direction from the information carrier 7, the radiation is reflected by the beam splitter 2 to the focusing sensor 8, the signal of which is summed with the bias voltage of the summing amplifier 11, the signal of which controls the mirror membrane of the element 4. 1 sludge.

Description

(21) 4367549 / 24-10

(22) 01/25/88

(46) 06/15/90. Bul No. 22

(71) Kiev Research and Development Institute of Peripheral Equipment

(72) A.F.Llevako

(53) 681.84.001.2CQ88.8)

(56) USSR Author's Certificate No. 1137515, cl. G 11 V 7/00, 1982. (54) DEVICE FOR RECORDING AND REPRODUCTION OF INFORMATION FROM REFLECTING OPTICAL MEDIA

(57) The invention relates to the accumulation of information by optical means and can be used in computing. The aim of the invention is to increase the reliability of the recording.

and reproduction of information in real time. The radiation of the radiation source 1 is reflected by a polarization beam splitter 2 in the direction of element 4 with a variable focal length, the forward-going quarter-wave plate 3, which passes for the second time after reflection from element 4 ,. In the reverse course, the radiation with almost no reflection passes the beam splitter 2, then an additional quarter-wave plate 5 and is focused by the lens 6 on the information carrier 7. In the reverse direction from the information carrier 7, the radiation is reflected by the beam splitter 2 to the focusing sensor 8, the signal of which is summed with the bias voltage of the summing amplifier 11, the signal of which controls the membrane element 4. 1 Il.

a ss

(L

ate

s

I The invention relates to the accumulation of information by optical means and can be used in computing as a device for recording and reproducing information in both real and divided time scales.

The aim of the invention is to increase the reliability of recording and reproduction of information in real time.

The drawing shows a diagram of the device.

The device contains a radiation source 1, a polarization beam splitter 2, a quarter-wave plate 3, an output 4 with a variable focal length, an additional quarter-wave plate 5, a lens 6, an information carrier 7, a focusing sensor 8, a DC amplifier 9, a source 10 bias voltage and sum 1; hinting amplifier 11.

The device is intended for operation both in real and divided time scales.

When playing information on a divided time scale, the device operates as follows.

The radiation of the radiation source 1 is reflected from the polarization splitter 2, passes a quarter-wave plate 3, hits the mirror membrane of element 4 with a variable focal distance, after which it passes through the quarter-wave plate 3 again and the beam splitter 2 ,. Then the ADVAL quarter-wave plate 5 passes and is focused by the lens 6 onto the surface of the information carrier 7. The radiation reflected from it, modulated by the information recorded on the carrier, passes through the lens 6 a second time, an additional quarter-wave plate 5, is reflected from the beam splitter 1 and hits the photosensitive surface of the focus sensor 8, which may contain, for example, an astigmatic element and a four-element , a photodetector with an electronic system for separating the information signal and the defocus signal (not shown). Defocus signal corresponding to the deviation of the information carrier in one direction or another relative to the focal plane

0

five

five

d

Q 5

five

lens 6, is fed to the amplifier 9 DC and after amplification (and adjustments, if necessary, the correction amplifier is not shown in the drawing) - to one of the inputs of summing amplifier 11. Its other input receives a constant voltage source 10 the displacement required to displace the mirror membrane of the element 4 into the work area (to give it the necessary radius of curvature). From the output of summing amplifier 11, the signal containing the constant component and the component of the focusing error signal is fed to element 4, which changes the focus position of the system element with variable focal length - lens 6 in accordance with the change in distance between lens 6 and the carrier 7 information. When recording information, the radiation of the radiation source i or the radiation source itself is modulated by a recorded information signal. The course of radiation and the operation of the device in real time are similar to those described above.

Improving the reliability of recording and reproducing information during operation of the device in real time is provided by minimizing radiation losses on the optical elements of the device, which is achieved by the proposed arrangement of quarter-wave plates 3 and 5, as well as by eliminating the effect of fluctuations of the radiation source power and other factors on the curvature the mirror membrane element with a variable focal distance of 4, since the curvature of the mirror membrane in the working area is determined only by the magnitude of the stabilized bias voltage.

Formula

A device for recording and reproducing information from a reflective optical medium containing optically coupled radiation source, a polarization beam splitter, a focus sensor, a variable focal length element, a lens and a quadruple plate, and a DC amplifier whose input is connected with an output of a focusing sensor, characterized in that, in order to increase the reliability of the sensor;

recording and reproducing information with a variable focal length of the real time scale, in it, and additional - between the polarized ones by an additional quarter-wavelength beam splitter and lens,

The shaft of the plate and the successively connected output of the DC amplifier are the single source of the bias voltage connected to another input of a summing amplifier, a quarter-wave amplifier, the output of which is connected

A new plate is located between the control input of the element with an implementation beam splitter and the elemental focal distance.

Claims (1)

Formula of Gaining A device for recording and reproducing information from a reflective optical medium containing optically coupled radiation source, a polarizing beam splitter, a focus sensor, a variable focal length element, a lens and a quarter-von plate, as well as a DC amplifier, the input of which is connected to the output of the focus sensor, characterized in that, in order to increase the reliability of recording and reproducing information in real time, an additional quarter-wave plate was introduced into it a series-connected bias voltage source and summing amplifier, a quarter-wave plate is located between the polarizing beam splitter and the element with a variable focal length, and the additional one is between the polarizing beam splitter and the lens ;; 5a, the output of a DC amplifier is connected to another input of a summing amplifier, the output of which is connected to a control input of a variable focal length element.