JPS60103527A - Optical disc device - Google Patents

Abstract

PURPOSE:To attain accurate tracking control without lowering the recording density in recording/reproducing a disc having a guide track by inverting the polarity of a tracking servo at a peak of a tracking error signal. CONSTITUTION:A reflected light of a disc is photoelectrically converted by a 2- split PINFD1 and the outputs of differential amplifiers 2, 12 become the tracking error signal (c) where the polarity is inverted. In moving a spot from a projected part to a recessed part of the disc, a microcomputer 11 turns off a tracking group switch 5, applies a signal (a) to a drive circuit 7 via an FF16 and a jump pulse generator 10 so as to jump the spot. The peak of the signal (c) is detected by a peak detector 15, an output (d) is fed to a changeover switch 13, where the polarity of the signal (c) is inverted, the output (d) is fed to the FF16 so as to apply a deceleration signal (f) of spot movement to an adder circuit 6. A stable point (g) of tracking control is detected from the signal (c) and the deflection angle of the tracking mirror is controlled so as to make the signal (c) zero by turning the switch 5 on.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a tracking control device for an -f# information recording/reproducing means in an optical disk device, and particularly to a tracking control device for a disk carved with uneven groove tracks. It is related to @snow.

[Background of the invention]

Conventionally, as an example of the information recording method of an optical disk device,
As shown in FIG. 1(b), a convex part on the surface of a disk in which uneven groove tracks have been cut in advance and whose surface is coated with a recording medium is irradiated using, for example, an original as a recording means. By doing so, recording media with varying duality ratios called recording dots are arranged to form concentric tracks or spiral tracks, and information is recorded depending on the length and spacing of these recording dots. be.

To read information from the disk, for example, the source is used as a viewing means as described above, and this is used to target the reflected light from the recording surface that is modulated depending on the presence or absence of recording dots on the disk. being done. On the other hand, the concave portion of the disk is used as a guide track for tracking control.

This recording/reproducing apparatus for a concavo-convex disk is provided with a so-called tracking servo control device that controls the rotation of a tracking mirror for deflection so that the degree Celsius irradiation light accurately tracks the information track of the disk.

FIG. 2 is a circuit diagram showing a conventional tracking servo control device in a recording/reproducing apparatus for a concavo-convex disk. In the figure, 1 is a 2-split PIN photodiode, 2 is a differential amplifier, 5 is a phase compensation circuit, 4 is an amplifier circuit, 5 is a Ni-Dracking loop 0N101i'F switch, 6 is an adder circuit, 7 is a drive circuit, 8 9 is a mirror drive coil, 9 is a zero cross detector, 10 is a jump pulse generator, and 11 is a microcomputer.

Next, I will explain the operation. The reflected light from the uneven disk (not shown) is photoelectrically converted by a two-split PIN photodiode 1, and a differential amplifier 2 generates a difference as shown in FIG. 1(a), which corresponds to a tracking error signal. I get a signal. This error signal is transmitted to the phase compensator 6:amplifier circuit 4. It is applied to a drive coil 8 that drives a ℃ tracking mirror (not shown) through a tracking loop ON10FF switch 5 and an adder circuit 6, and the deflection angle of the tracking mirror is controlled so that the error number -4N becomes zero. When a spot is to be jumped from a convex portion to a convex portion of an adjacent track, the microcomputer 11 turns off the tracking loop 0N10FF switch 5, generates a jump pulse from the jump pulse generator 1o at the same Fi#, and
Add this to drive circuit 7 to jump the spot vertically on the track. At this time, the tracking error signal increases as it moves away from the track position, as shown in FIG. 1(a).

After passing through a certain extreme value, it becomes zero at the position of the guide track. The position td) is detected by a zero cross detection 69, and its output is applied to the adder circuit 6 via a jump pulse generator 10 to decelerate the movement of the spot. When the spot moves further, the tracking error signal is intensified with the opposite polarity to the previous one.

After passing through a certain extreme value, the signal becomes zero at the next track position (e). Detect that position (e) using a known method, and turn on the tracking loop ON10FF switch 5 so that the tracking error signal becomes zero. The deflection angle of the tracking mirror is controlled.

However, with the method of detecting the zero level of the tracking error signal and applying tracking control, there is a problem in that only one of the convex or concave portions of the disk can be used as an information track.

(Object of the Invention) An object of the present invention is to provide an apparatus that can obtain accurate tracking control without reducing recording density when recording and reproducing a disc having a guide track.

[Summary of the invention]

In order to achieve the above object, the present invention adopts a method of newly providing a peak detector and inverting the polarity of the tracking servo at the peak of the tracking error signal.

[Embodiments of the invention]

Embodiments of the present invention will be described below using cooling drawings. FIG. 6 shows a block diagram of an embodiment of the present invention, in which 1 is a two-split PIN photodiode, 2.
12 is a differential amplifier, 13 is a changeover switch, 6 is a phase compensation circuit, 4 is an M width circuit, 5 is a tracking loop 0N1
0F'F switch, 6 is an adder circuit, and 7 is a drive circuit.

8 is a mirror drive coil, 14 is a full-wave rectifier, 15 is a peak detector, and 16 is a flip-flop.

10 is a jump pulse generator, and 11 is a microcomputer.

Next, the operation will be explained using the waveform time charts of each part shown in FIGS. 3 and 4. Concave and convex disc (not shown)
The reflected light is photo-electrically converted by the 12-split PIN photodiode 1, and is applied to the polarity-reversed swords of the differential amplifiers 2-12. The outputs of the differential amplifiers 2 and 12 have the same absolute value, resulting in a difference signal corresponding to a tracking error signal with reversed polarity. One of the difference signals is selected by a changeover switch 16. The selected difference signal is applied to a drive coil 8 that drives a tracking mirror (not shown) via a phase compensation circuit 3, an amplifier circuit 4, a tracking loop 0N10F'F switch 5, and a zero arithmetic circuit 6. The deflection angle of the tracking mirror is controlled so that the signal becomes zero.

When moving the spot from the convex part (or convex part) of the disk to the fourth part (or convex part), the microcomputer 11 sends the fourth tracking loop OF 'F' signal.
Figure (a) is generated and the tracking loop is 0N10FF.
Switch 5 is turned off. At the same time, the jump trigger signal (b) from the microcomputer 11 is applied to the input of the seven lip-flop 16, and its output (
e) is differentiated via the jump pulse generator 10 and added to the adder circuit 6 as a jump pulse (f). The output of the adder circuit 6 is applied to a drive circuit 7 to cause the spot to jump in the vertical direction of the track. At the same time, the tracking error signal (C) is input to the full-wave rectifier (14-), the peak of the output signal is detected by the peak-to-peak detector 15, and the output signal (d) is applied to the changeover switch 13 to generate the tracking error signal. Reverse the polarity of (C).

Further, at the same time as detecting the peak of the tracking error signal CC), the output (d) of the peak detector 15 is applied to the flip-flop 16, and its output (e) is applied to the jump pulse generator 10y! / is differentiated and applied to the blade calculation circuit 6 as a spot movement deceleration signal (f). From the tracking error signal (C), the tracking control stability point (
g) That is, detect the point where the spot is on the four parts of the disc, and track loose 0N10F I! When switch 5) is turned on, the deflection angle of the tracking mirror is controlled so that the tracking error signal becomes zero.

Note that it is possible to input video signals, image signals, audio signals, codes, etc. as recording information into the guide track, which is a concave portion of the disc.

In addition, both concentric disk and spiral disk,
Recording and reproduction can be performed in three patterns: only concave parts, only convex parts, and mixed concave and convex parts, and special recording and reproduction of still images, reverse rotation, triple speed, etc. is possible.

〔Effect of the invention〕

As explained above, according to the present invention, by detecting the peak of the tracking error signal and reversing the polarity of the tracking error signal, both the concave part and the convex part of the disc in which uneven grooves are carved are detected. It is possible to record information and has the effect of increasing recording density.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the relationship between a conventional tracking error signal and an uneven disk surface, FIG. 2 is a block diagram showing a conventional tracking servo control device, and FIG. 3 is a block diagram showing an embodiment of the present invention. Asahi 41-kiri is Kube Sakan I Itanguki J--K Poxban. 1...2-split PIN photodiode. 2.12...Differential amplifier. 3... Phase compensation circuit, 4... Amplification circuit. 5...Tracking loop ON/(1'F switch,
6...Addition circuit. 7... Drive circuit, 8... Mirror drive coil, 9... Zero cross detector. 10... Jump pulse generator, 11... Microcomputer. 15... Changeover switch, 14... Full wave rectifier, 15... Peak detector. 16...Flip-flop. Figure 4 Hoka

Claims (1)

[Claims] 1. Information recording means for recording information on the recording medium by coating a recording medium on a disk having concentric or spiral grooves, forming unevenness on the recording medium, and recording information on the recording medium; and the recorded information. an information reproducing means for reading from a track, and a former information recording means and a pickup of the information reproducing means having a tracking error signal detecting means for tracking control, wherein the recording medium is a guide track for tracking control. As a means for recording information in the recess and reproducing information in the recess,
An optical disc device characterized in that the peak of the tracking error signal is detected and the polarity of the tracking error signal is inverted.