JPS58203638A - Optical reproducing device - Google Patents

Abstract

PURPOSE:To facilitate the execution of appropriate jumping to a desired track, by controlling the tilt of a tracking mirror within a prescribed range at a place near the desired track. CONSTITUTION:A designated address A fed through a console 23 is then fed to a microcomputer 18. While the address B of the using track which is read out by an address signal discriminating circuit 17 is fed to the computer 18. Then a subtraction (A-B) is performed to give a rough retrieval to shift a light beam 2 to a track near the designated address. When the DC component of the tracking driving voltage is set within a prescribed voltage range, the jumping commands equivalent to the number of pieces of results of subtraction are delivered to a jumpting driving circuit 26 from the computer 18. Then the angle of a tracking mirrow 5 is varied to perform a fine retrieval to detect the desired address. In this case, the incident light beam 2 is approximately vertical to the surface of a disk 7 at the place near the desired track. This improves the envelope of a reproduced signal and stables the tracking.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical playback device (ζ) for recording signals such as video or audio at high density on a recording medium F, and for producing a signal that disparages the recorded signal track. By jumping the incident light beam almost perpendicularly to the surface of the recording medium and moving it to the desired track L, a good tracking condition is always obtained, and as a result, the time required to search for the desired track can be shortened. It provides equipment.

Conventionally, a large number of video signals can be recorded on a disc-shaped optical recording medium by providing lζ address signals. 1! A playback device has been proposed that searches for and plays back the video at a specific address from a disc that is currently in storage. As a means of this, the light beam is controlled so that it is positioned on a track on a record carrier (hereinafter referred to as record carrier), and the reflected light or record carrier that is reflected from the record carrier of the light beam is controlled. Detecting the transmitted light that passes through a photodetector, reading the address signal of the track where the light beam is currently located based on the detection output, and calculating the difference between the current address and the designated address;
When the difference is less than a predetermined number l: (for example, 11 bodies), the number of pulses corresponding to the difference is given to the stepping motor ζ,
The optical transfer table is moved through the feed screw for transfer, and a rough search is performed near the desired track. Then, the difference between the read address and the specified address is a predetermined number of lines, until the number of uplinks is less than 1 ([
Repeat the coarse search described above. Then turn on tracking
L. When the difference between the read address and the specified address decreases by a predetermined number, the light beam jumps toward the specified track (hereinafter, jumping the light beam from one track to another track is referred to as "jumping") by dense search. Search for the desired address. Turn on tracking after the rough search mentioned above
At point L, the light beam only needs to be within the tracking range, so the inclination of the tracking mirror that causes the light beam to jump during the dense search is large (or small).
There is a possibility that it has become.

At this time, the tilt of the tracking mirror is large (or small).
If so, even if the number of lines to be jumped is within the predetermined number (for example, ±15 lines), if you jump further in the direction of the inclination, the tracking may be lost and the rough search described above may be repeated. It takes longer.

SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned problem and perform appropriate jumping. means for detecting that a signal for driving the deflecting means for the reproducing light beam is within a predetermined voltage range; a light beam jumping means for jumping the light beam to another track; and a read current track. If the result of subtraction between the address and the specified track address is a predetermined number or more, drive the moving means rn+;
control means for driving the reproduction light beam jumping means when it is detected that the subtraction result is within a predetermined number and that a signal received by the detection means and softening the reproduction light beam deflection means is within a predetermined voltage range; By creating a configuration having the following, the intended purpose was achieved.

Embodiments of the present invention will be described below based on the drawings.

In Fig. 1), a light beam (2) generated from an ie-Ne laser or a semiconductor laser (11) passes through a medium lens (3), a beam splitter (4), and is directed by a tracking mirror (5). A convergent lens (
6) One frame is converged onto the disk (7). Disk rotation motor (8) Upper disk (7)
The first reflected light (9) is reflected by the converging lens (6) again.
The beam passes through the tracking mirror (5), is redirected by the beam splitter (4), and is input to the two-split photodetector QO. The outputs of the two-split photodetector OQ are respectively input to envelope detection circuits (lla) (llb), and the respective outputs are applied to a differential amplifier (6).
A difference signal is obtained and amplified. The difference signal obtained from the differential amplifier (2) is inputted to the tracking element drive circuit α411 via the tracking control circuit (to) which includes a phase compensation circuit for the servo system (for example, a lead/lag compensation circuit). .

The output of the drive circuit 04 causes the tracking element (to) to be driven, and the angle of the tracking mirror (5) attached to the tracking element OFM1 changes, so that the converged light spot on the disk (7) is tracked. Tracking is performed by scanning the top.

The outputs of the two-split photodetector a0 are added together in a video signal reproducing circuit OQ to obtain a video internal signal. The video playback signal contains address signal information corresponding to each track within the vertical retrace, and the address signal of the track is read out by the address signal identification circuit Qη, and the microcomputer (to) ( (hereinafter referred to as microcontroller).

The semiconductor laser (1), the intermediate lens (3), the beam splitter (4), the tracking element, and the converging lens (6) are mounted on the same substrate, and the substrate is attached to the stepping motor as an optical transfer table. It is housed in the transport feed screw (2). When the microcomputer (9) sends a search command to the slap motor drive circuit (Foundation), the feed screw (c) for transfer moves back and forth, the optical transfer table α cast also moves back and forth, and the light The beam (2) moves back and forth almost perpendicular to the disk direction.

When searching for a certain address, when the designated address (assumed to be A) is input to the operator console, the information is input to the microcomputer (G).

On the other hand, the current track address (referred to as B) read out from the address signal identification circuit Q7) is input to the microcomputer (to), and subtraction (A-B) is performed. The subtraction result is the predetermined number (
For example, if it is more than ±15 lines), a drive command is issued from the microcomputer (to) to the stepping motor drive circuit (e),
The stepping motor (1) is driven, and accordingly the optical transfer stage (IQ) is moved, and a rough search is performed in which the optical beam (2) is moved to a track near the designated address.Therefore, the output of the two-split photodetector a0 is The difference signals obtained from the envelope detection circuits (lla) and (llb) are input to the differential amplifier (2), respectively, and the difference signals are input to the tracking control circuit 0. A low-pass filter that removes the generated components (
Above 1. P
The DC component of the tracking drive voltage is converted by the D converter AT and taken in by the microcomputer (to).The DC component of the tracking drive voltage makes the incident light beam (2) almost perpendicular to the surface of the disk (7), which is suitable for jumping. Within a certain range E1 For example, set the tracking mirror at 45 degrees and increase the number of jumps by ±1
If the voltage is within the range corresponding to 5 motors, the microcomputer (to) sends the drive command to the stepping motor drive circuit (
2), and the stepping motor (E) is driven to move the optical transfer table αl. After that, in the same way, 2-split photodetector 4, envelope detection circuit (Ila) (llb
), the differential amplifier (6), and the tracking drive voltage via the tracking control circuit are applied to the LPFM, A/D converter (
2) is input to the microcontroller (to), and the DC component of the tracking drive voltage is input to the incident light beam 12 before and after jumping.
1 and the disk (7) surface are both considered to be approximately perpendicular to each other until a voltage corresponding to a predetermined range is reached. Then, when the DC component of the tracking drive voltage falls within the predetermined voltage range, the result of subtraction between the displayed track address and the designated address obtained by [7] address signal identification circuit 07) becomes a predetermined number (f), If the number of jumps is within 115 lines), the microcontroller (7) will output a jumping command corresponding to the number of lines, or the jumping drive circuit will output a jump command corresponding to the number of jumps from the jumping drive circuit (7). The output is superimposed on the output of the tracking side diagonal (b) road wheel in the tracking element drive circuit (14), and the angle of the tracking mirror (5) is changed accordingly to perform a fine search to detect the destination address. In this case, since the incident light beam (2) and the surface of the disk (7) are approximately perpendicular to each other at the desired tracked point 6ζ, the envelope of the reproduced signal is good and the tracking is stable.
Proper jumping to the desired track becomes easy to master.

As mentioned above, according to Akira Hontori, near the desired trunk,
By controlling the inclination of the tracking mirror within a predetermined range, that is, by keeping the incident light beam almost perpendicular to the disk surface, the envelope of the reproduced signal can be detected well and the tracking can be stabilized. Appropriate jumping to a desired r-rack can be easily performed. In addition, since the inclination of the tracking mirror is controlled within a predetermined range, tracking increases when jumping to a desired track, and the desired track can be detected at high speed without having to look at the address and perform a rough search. be able to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an optical reproducing apparatus according to the present invention. (5)...Tracking mirror, 03...Tracking control circuit, 041...Tracking element drive circuit, (to)...Tracking element, [phase]...Microcomputer, (1)...・Stepping motor,
嬶...Stepping motor drive circuit, (C)...Low pass filter, (E)...Al1) converter, (
e)...Jumping drive circuit agent Yoshihiro Morimoto

Claims (1)

[Claims] 1. In an apparatus for reproducing a signal JPj from a signal track on a disk record carrier by optical means, a moving means for moving a reproducing optical head near the track to be reproduced;
a reproduction light beam deflection means for tracking the reproduction track; a means for detecting that a signal for driving the reproduction light beam deflection means is within a predetermined voltage range; and means for directing the light beam to another track. If the result of subtraction between the current track address read and the designated track landing is greater than or equal to a predetermined number, the moving means is driven, and if the result of subtraction is within the predetermined number and the detection means and a control means for driving the reproduction light beam jumping means when it is detected that the signal for driving the reproduction light beam polarization means is within a predetermined voltage range. The means for detecting that the signal that causes the deflection means to be within a predetermined voltage range includes:
The drive signal for the reproduction light beam deflection means is passed through a low-pass filter, and the A/D converter 411 converts the drive signal a.
The optical reproducing device according to claim 1, characterized in that it has a configuration I for obtaining the travel amount.