JPS60217538A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To track the information with high accuracy by separating a laser luminous flux into main and secondary beams to follow after two guide tracks with the secondary beam and recording the information at the middle of the guide track. CONSTITUTION:A laser luminous flux is separated into main and secondary beams by an optical system to follow after guide tracks by light spots 6a and 6c formed by the secondary beam. The positions of both light pots are controlled so as to obtain an equal quantity of reflected light between both spots. Thus, a light spot 6b is always set at the center of a track with a prescribed distance secured from both spots 6a and 6c respectively. Then the recording is carried out by the spot 6b to form a pit 17. Therefore the spot 6c is set on a guide track 16a and never put on the pit 17. This eliminate the variation of light quantity and attains the tracking of information with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an optical information recording and reproducing device for an optical memory device of an optical disk tube, and in particular to an optical information recording and reproducing device for an optical disk memory device that records and reproduces information in real time. Relating to tracking devices.

[Background of the invention]

Conventionally, optical video discs, PCM optical discs.

In optical disk memory devices that record and reproduce digital information, the information track on the disk surface is measured ±0.1 μm.
Tracking technology that tracks with a certain degree of accuracy has become essential. As a typical method, as shown in FIG. 1, a method is known in which three light spots are formed on the disk surface and tracking is performed using these spots.

(For example, see Japanese Patent Publication No. 53-13123.) In the first diagram, a laser beam 2 emitted from a laser light source 1 becomes a parallel beam by a lens 3, and by a diffraction grating 4,
After splitting into three beams of 0th order light and ±1st order light, mirror 15
and is focused by the aperture lens 5 onto the disk 7 as three light spots 6a, 6b, and 6c. Three light spots 6a, 6b, and 6c are formed on a track 16 on the disk 7 so as to have an inclination of θ with respect to the direction of the track 16, as shown in FIG.

The reflected light beam from the surface of the disk 7 is guided by a half mirror 8 onto photodetectors 10a, 10b, and 10c.

At this time, the light spots 6a, 6b, and 6c are detected by the photodetector 10a,
Detected corresponding to 10”b・, 10c. Photodetector 2
The output from 0b is led to a signal reproducing circuit via an amplifier 12. The outputs of the photodetectors 10a and 10c pass through a differential amplifier 11 to become a differential output, and after passing through a servo circuit 13, are guided to a driver 14 of a mirror 15, which rotates the mirror 15 in accordance with the amount of track deviation. Perform tracking. That is, if the track 16 shifts to the right in the first spring, the amount of reflected light from the light spot 6a decreases, and the amount of reflected light from the light spot 6C increases. The opposite is true if the track 16 shifts to the left. The mirror 15 may be controlled so that the amounts of reflected light from the detectors 68 and 60, that is, the outputs from the photodetectors 10a and 10c, are always the same. This method can perform stable tracking for optical video discs or optical PCM discs where information is formed on the tracks in advance, but it is possible to perform stable tracking for discs with information formed on the tracks in advance, such as optical video discs or optical PCM discs. Conventionally, optical disk memories that record and play back data have had major drawbacks.

In other words, as shown in FIG. 3, guide tracks 16a, 16b, and 16c are previously formed on the disk.
Furthermore, in an optical disk memory, a recording film such as a metal thin film is formed, and pits (holes) 17 corresponding to information are formed in this recording film. Information is recorded by a light spot 6b. Light spot 6a.

When trying to obtain a tracking signal using 6c, the light point 6
Since the light spot a is located in an area where information is not recorded and the light spot 6C is located in an area where information is already recorded, the amount of reflected light is not equal even in a state where there is no track deviation. Moreover, the non-uniformity varies greatly depending on the pattern of recorded information, that is, the arrangement pattern of pits, and this greatly deteriorates tracking accuracy.

[Purpose of the invention]

The present invention solves the above-mentioned drawbacks of conventional tracking and provides an optical information recording and reproducing device that can perform highly accurate information tracking.

[Summary of the invention]

In order to achieve this object, the present invention performs tracking across two guide tracks and records information between the guide tracks, thereby achieving highly accurate tracking without being affected by the recorded silver pits. It is something.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to examples.

FIG. 4 is a diagram illustrating an embodiment of the present invention.

In the figure, among the three light points 6a, 6b, and 6c, 6a is located on the right side of the guide track 16b, 6C is located on the left side of the adjacent guide track 16a on the left, and 6b is located on the left side of the guide track 16a adjacent to the left. It is located in the area between tracks 16a and 16b.

, 6a, and 6c, when the track shifts to the right, the amount of reflected light from 6c increases and the amount of reflected light from 6a decreases. If the truck shifts to the left, the opposite will occur. If the position of the light spot is controlled so that the amounts of reflected light from 6a and 6c are exactly equal, the light spot 6b will always be located at the center between the tracks. When information is recorded using 6b, a pit 17 is formed at the center between the tracks.

Since the light spot 6c is placed on the guide track 16a,
Even if the light does not overlap the pit 17 and is in the area where information has been recorded, there is no fluctuation in the light amount, and when there is no track deviation, the light amount is equal to that of the light spot 6a.

Furthermore, as shown in the case of recording and reproducing digital information, pits 18 of recorded silver information may be recorded between the guide tracks. The same conventional apparatus as shown in FIG. 1 may be used to create and detect the three light spots in FIG. 4.

Regarding the guide track, there are no particular restrictions on its depth and width, but for example, the pitch is 2.5μ.
m, width approximately 0.4 to 0.8 μm, depth λ/4 to λ/8
Appropriate. Furthermore, information recording media are not particularly regulated, but for example,
a, Se, As.

It is preferable to use a material containing Pb, In, etc. and having a thickness of about 100 to 500 layers.

〔Effect of the invention〕

As described above, by using the present invention, it is possible to provide an optical information recording/reproducing apparatus that records and reproduces information in real time while performing stable tracking.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of an optical information recording/reproducing device;
FIG. 2 is a diagram showing a conventional information tracking method. FIG. 3 is a diagram for explaining the operation, and FIG. 4 is a diagram for explaining one embodiment of the present invention. 7th evil no. 2 2nd evil/2 Figure 3 No. 4 Ro no Otsu. tlb /Otsut 72/7

Claims (1)

[Claims] 1. In an optical information recording and reproducing apparatus that irradiates a recording medium having a guide track with a laser beam from a laser light source and controls the irradiation position of the laser beam so that information is recorded or reproduced along the guide track, the laser The light beam is separated into a main beam and a sub beam, and the sub beam tracks the guide track of the recording medium, and at the same time, the main beam, which is in a predetermined positional relationship with the sub beam, tracks the guide track in the intermediate area between the guide tracks. An optical information recording and reproducing device that records or reproduces information.