JPH04319569A - Optical disk device and its control method - Google Patents

Abstract

PURPOSE:To provide an optical disk driving device capable of accessing suitably to both of an optical disk whose spiral directions of the recording tracks of both faces are formed oppositely each other and the optical disk whose spiral directions of the recording tracks of both faces are formed the same. CONSTITUTION:This device is provided with an amplitude detector 34 detecting the amplitude value of a tracking error data TEd outputted by a tracking error detector 29 and the rotational direction of the optical disk is reversed when the value of the tracking error data TEd obtained in an initial operation is smaller than a prescribed value.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention relates to an optical disk device and an optical disk device for detecting a tracking error based on the difference in detection level between two wobble pits of an optical disk in which a servo bite consisting of two wobble pits and one clock pit is arranged. This article relates to its control method.

0002

2. Description of the Related Art Generally, in an optical disk device that uses an optical recording medium or a magneto-optical recording medium (hereinafter collectively referred to as an optical recording medium) as a recording medium, recording surfaces are formed on both sides of the recording medium. Normally, the drive device of an optical disk device is equipped with only one optical pickup device for recording/reproducing data, so only one recording surface can be accessed at the same time. When recording/reproducing data, it is necessary to reverse the recording surface to be accessed manually or using a reversing mechanism, resulting in a situation where data access time becomes longer.

[0003] Conventionally, for example, Japanese Unexamined Patent Publication No. 1986-20
As disclosed in Japanese Patent No. 8653, two optical heads (optical pickup devices) and a bias magnetic field generation mechanism are provided on both sides of an optical disk, so that data recording/reproducing operations can be performed using either optical head. Therefore, an optical disc has been proposed in which both recording surfaces of the disc can be accessed efficiently.

Furthermore, in this conventional device, the recording tracks formed on one recording surface of the optical disk are formed in the opposite spiral direction to the recording tracks formed on the other recording surface, and the recording tracks formed on the other recording surface are formed in the opposite spiral direction. By making the data recording format the same, the optical heads that access both recording surfaces are able to trace each recording track in the forward direction.

[0005]

[Problems to be Solved by the Invention] However, this conventional device has the following disadvantages.

That is, in optical discs used in optical disc devices other than the conventional device described above, the recording tracks formed on both recording surfaces are in the same spiral direction. There are two different types of optical discs, and there is a risk that an optical disc on which data has been recorded by one optical disc device cannot be accessed by another optical disc device.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an optical disc device and a control method thereof that can appropriately access two types of optical discs having different spiral directions. It is said that

[0008]

[Means for Solving the Problems] The present invention provides an optical disk rotation means capable of forward and reverse rotation of an optical disk, an amplitude detection means for detecting the amplitude of a tracking error signal representing a tracking error, and a reference synchronized with the detection timing of a clock pit. When the synchronization between the clock forming means that forms the clock signal and the clock forming means is completed, the detected value of the amplitude detecting means is input, and if the detected value does not reach a predetermined value, the optical disk rotating means changes the direction of rotation of the optical disk. It is equipped with control means for reversing the rotation.

[0009] Furthermore, when the synchronization of the reference clock signal with the detection timing of the clock pit is completed, the amplitude value of the tracking error signal is detected, and if the detected amplitude value is not a predetermined value, the rotation direction of the optical disc is This is done by reversing the .

0010

[Operation] Therefore, when starting to use the installed optical disc, the rotation direction of the optical disc is determined.
The recording surface on which recording tracks in the reverse spiral direction are formed can be appropriately accessed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an optical disk drive according to an embodiment of the present invention. Note that in this case, a write-once optical disc using an optical recording medium is used as the recording medium.

In the figure, a turntable 32 provided on the rotating shaft 2 of the spindle motor 1 is connected to an optical disk 4.
are removably attached, and an optical pickup device 5 is provided at a position for detecting one recording surface. The optical pickup device 5 is also provided with a seek mechanism 6 for reciprocating the optical pickup device 5 in the radial direction of the optical disc 4.

FIG. 2 shows an example of the optical system of the optical pickup device 5. As shown in FIG. Note that this optical system uses an astigmatism method as a focusing error detection method.

In the figure, signal light output from a semiconductor laser element 11 is converted into parallel light by a coupling lens 12, and enters a polarizing beam splitter 13 as P-polarized light. It is reflected by the beam splitter 13 and guided to the 1/4 wavelength plate 14 .

The P-polarized signal light transmitted through the quarter-wave plate 14 is converted into circularly polarized light by the quarter-wave plate 14, and then condensed by the objective lens 15 to be focused on the recording surface of the optical disc 4. imaged.

The reflected light from the optical disk 4 passes through the objective lens 15 and is converted into substantially parallel light, and then enters the quarter-wave plate 14 again. As a result, the 1/4 wavelength plate 14
The reflected light that has passed through is converted into linearly polarized light whose orientation is orthogonal to the incident light, and is thereby transmitted through the polarizing beam splitter 13 .

In this way, the polarizing beam splitter 1
The reflected light from the optical disk 4 that has passed through the lens 16
The light then passes through the cylindrical lens 17 and enters the light-receiving element 18 whose light-receiving surface is divided into four parts.

The light receiving surface 18a of this light receiving element 18
A focusing error signal is obtained based on the difference between the sum of the light reception signal obtained from the light reception surface 18b and the light reception signal obtained from the light reception surface 18d. In addition, the light receiving element 18
A reproduced signal is obtained by summing the light-receiving signals obtained from the light-receiving surfaces 18a, 18b, 18c, and 18d.

The objective lens 15 also includes an objective lens 1.
An objective lens moving mechanism for moving the lens 5 in the tracking direction and the focusing direction is attached.

In this embodiment, the recording tracks formed on the recording surface of the optical disk 4 are provided with servo bytes SB1, SB1, and SB1 as shown in FIG. 3 at predetermined channel bit intervals.
Servo data consisting of SB2 is formed.

The servo bite SB1 consists of wobble pits PA and PB that are formed at positions shifted by a distance of 1/4 track in opposite directions from the center TK of the recording track, and are used to detect tracking errors of the laser beam LB. , servo byte SB2 is located at the center T of the recording track.
It consists of a clock pit PC arranged at K for synchronizing the reference clock of the signal reproduction system.

In this case, wobble pit PA is placed at bit 4 of servo byte SB1, wobble pit PB is placed at bit 7 of servo byte SB1, and clock pit PC is placed at bit 7 of servo byte SB1.
It is placed at bit 10 of B2.

Therefore, first, with the synchronization of the reference clock of the signal reproduction system completed in the clock pit PC, the level of the reproduction signal obtained from bits 4 and 7 of the servo byte SB1 is detected, and these two detection levels are By comparing these, it is possible to know the amount of deviation between the center of the laser beam LB and the center TK of the recording track, and the direction of the deviation.

FIG. 4 shows an example of a main part of a control system of an optical disk drive according to an embodiment of the present invention.

In the figure, the light receiving surface 18 of the light receiving element 18
The light receiving signals Pa and Pb obtained from the light receiving surfaces 18c and 18b of the light receiving element 18 are respectively applied to the two input terminals of the adder 21, and the light receiving signals Pa and Pb obtained from the light receiving surfaces 18c and 18d of the light receiving element 18 are respectively applied to the two input terminals of the adder 21.
c and Pd are respectively added to the two input terminals of the adder 22, and the addition output PDa of the adder 21 is added to the subtracter 2.
3 and one input terminal of the adder 24, and the addition output PDb of the adder 22 is
It is applied to the minus side input terminal of the subtracter 23 and the other input terminal of the adder 24.

The subtracted output of the subtracter 23 is applied to the focusing servo control section 25 as a focusing error signal FE, and the added output of the adder 24 is applied to the analog/digital converter 26 as a reproduced signal RF, and It is added to the binarization circuit 27.

The focusing servo control unit 25 performs focusing servo control to align the focus of the laser beam of the optical pickup device 5 with the recording surface, and forms a control signal SF corresponding to the input focusing error detection signal FE. , and outputs the control signal SF to the focusing actuator drive unit 28.

Focusing actuator drive unit 28
is for driving a focusing actuator that drives a mechanism for moving the objective lens 15 in the focusing direction in the objective lens moving mechanism of the optical pickup device 5 in accordance with the applied control signal SF.

The analog/digital converter 26 converts the reproduced signal RF into a digital signal, and the reproduced data RFd obtained as a result of the conversion is applied to the tracking error detection section 29.

The binarization circuit 28 binarizes the reproduced signal RF using a predetermined threshold value, and the binarized data RFb obtained as a result of the processing is processed by a PLL (Phase Locator).
cked Loop) circuit 30.

The PLL circuit 30 detects the reproduced data of the clock pit PC of the servo byte SB2 from the data RFb, and generates a reference clock C synchronized with the detection timing.
The reference clock CP is applied to the timing generator 31. In addition, the PLL circuit 30, upon completion of synchronization of the reference clock CP,
The control unit 3 sends a lock completion signal LP to notify that effect.
Output to 2.

The timing generation section 31 generates a reference clock C.
In synchronization with P, wobble pit P of servo tool SB1
It forms a timing signal TT for detecting A and PB, and the timing signal TT is applied to the tracking error detection section 29.

The tracking error detection signal 29 samples the reproduced data RFd at timings corresponding to the wobble pits PA and PB in synchronization with the timing signal TT, and forms the difference between the values of the sampled wobble pits PA and PB. , the difference is calculated as tracking error data T
The tracking error data TEd is output as Ed, and the tracking error data TEd is applied to the digital/analog converter 33 and the mysterious area detector 34.

The digital/analog converter 33 converts the tracking error data TEd into a corresponding analog signal, and the converted output is applied to the tracking servo control section 35 as a tracking error signal TE.

The tracking servo control unit 35 performs tracking servo control to cause the laser beam of the optical pickup device 5 to follow the recording track, and outputs a control signal S corresponding to the input tracking error detection signal TE.
T, and outputs the control signal ST to the tracking actuator drive section 36.

The tracking actuator drive unit 36 drives a tracking actuator that drives a mechanism for moving the objective lens 15 in the tracking direction in the objective lens moving mechanism of the optical pickup device 5, in accordance with the applied control signal ST. .

The amplitude detector 34 detects the amplitude value of the tracking error data TEd, and the detection result is applied to the control section 32.

The spindle motor drive unit 37 rotates the spindle motor 1 in the forward rotation direction and the reverse rotation direction, and drives the spindle motor 1 to rotate in the rotation direction and rotation speed instructed by the control unit 32. .

The control unit 32 controls the operation of this optical disk drive, and in addition to the above-mentioned elements, controls the drive control system of the seek motor 6 and the interface for exchanging data with the host device. We also do

With the above configuration, when the optical disc 4 is loaded, the control section 32 performs the following initial operation.

First, when the optical disk 4 is loaded, the control section 32 instructs the spindle motor drive section 37 to drive in the forward rotation direction with a target speed specified, and thereby the spindle motor drive section 37 37 rotates the spindle motor 1 in the normal rotation direction at a specified target speed.

[0043] Furthermore, at the time when the optical disc 4 is loaded, the optical pickup device 5 is stopped at a position (initial position) where the approximate center of the optical disc 4 can be detected. It becomes possible to detect signals from the rotating optical disc 4.

Then, as shown in FIG. 5, the control section 32 first instructs the focusing servo control section 35 to start focusing servo control (process 101).
, waits until the lock completion signal LP is output from the PLL circuit 30 (NO loop of judgment 102).

At this time, at the initial stage, the focus of the laser beam of the optical pickup device 5 does not coincide with the recording surface of the optical disk 4, so a focusing error signal FE corresponding to the error is obtained, and the focusing servo control is performed. As a result, the focusing servo control section 35 receives a control signal S in the direction of reducing the error to zero.
Focusing actuator drive section 28 forming F
Output to.

As a result, the objective lens 5 is driven so that the focus of the laser beam coincides with the recording surface of the optical disk 4, and this operation is repeated to drive the optical pickup device 5.
The focus of the laser beam follows the movement of the recording surface of the optical disc 4.

In this way, in a state where the focus of the laser beam of the optical pickup device 5 follows the movement of the recording surface of the optical disk 4, the optical pickup device 5 can reproduce recorded information on the recording surface of the optical disk 4. The state is such that a servo data signal, a user data signal, etc. appear in the reproduced signal RF.

Therefore, the component of the clock pit PC appears in the binarized data RFb output from the binarization circuit 27, and the PLL circuit 30
Based on the detection timing of C, a synchronization pull-in operation of the reference clock CP is performed, and when the synchronization pull-in operation of the reference clock CP with respect to the detection timing of the clock pit PC is completed, a lock completion signal LP is output to the control section 32.

As a result, in the process being executed by the control unit 32, the result of determination 102 becomes YES.

Now, when the synchronization pull-in operation of the reference clock CP output from the PLL circuit 30 is completed in this way, the timing signal TT output from the timing generation section 31 is applied to the wobble pits PA, PB of the servo byte SB1. It is precisely synchronized with the detection timing of .

Therefore, when the spiral direction of the recording track formed on the recording surface of the optical disc 4 and the rotational direction of the optical disc 4 match, the tracking error detection section 29 detects the wobble pit PA of the servo bite SB1, The reproduction data RFd can be appropriately detected at the timing of PB, and the tracking error data T is based on the difference between the reproduction data RFd detected at each timing.
Ed is appropriately obtained.

[0052] As a result, the tracking servo control section 3
5 can obtain appropriate tracking error data TE. Therefore, when the control unit 32 issues an instruction to start the operation, the tracking servo control unit 35 performs an appropriate tracking servo control operation, and as a result, the optical pickup The laser beam of the device 5 follows the recording track of the optical disc 4.

Furthermore, before the control operation of the tracking servo control unit 35 starts, the optical pickup device 5
Since the laser beam does not follow the recording track of the optical disk 4, the value of the tracking error data TEd output from the tracking error detection section 29 is approximately
It changes with an amplitude corresponding to the maximum value of the tracking error, and the amplitude value of this tracking error data TEd is detected by the amplitude detector 34 and notified to the control unit 32.

On the other hand, when the spiral direction of the recording track formed on the recording surface of the optical disc 4 and the rotational direction of the optical disc 4 match, the wobble pit PA of the servo bite SB1, at the timing of the timing signal TT, Since PB cannot be detected, the reproduced data RFd detected at each timing by the tracking error detection unit 29 becomes uncertain data at that timing, and therefore the tracking error formed based on the difference between these detected data. The data TEd is a meaningless signal, and its amplitude value is very small.

Therefore, when the lock completion signal LP is input from the PLL circuit 30, the detection value of the amplitude detector 34 is checked, and if the value is larger than a predetermined value, the spiral direction of the recording track of the optical disc 4 is determined. optical disc 4
If the detected value of the amplitude detector 34 is less than a predetermined value, it can be determined that the spiral direction of the recording track of the optical disc 4 and the rotation direction of the optical disc 4 do not match. It can be determined that

Therefore, after the result of judgment 102 becomes YES, the detection value of the amplitude detector 34 is checked, and if the result is good (the result of judgment 103 is YES), the direction of rotation of the optical disc 4 is determined. Since the direction is appropriate, the operation of the tracking servo control unit 35 is started (processing 104), and the process moves on to the subsequent processing.

On the other hand, when the result of the judgment 103 is NO, the control section 32 causes the spindle motor drive section 37 to once stop the spindle motor 1 and then rotate the spindle motor 1 in the reverse direction (process 105). )
, the process moves to judgment 102 and waits until the lock completion signal LP is output from the PLL circuit 30 again.

In this way, in this embodiment, after the optical disc 4 is loaded and before the optical pickup device 5 starts the data recording/reproducing operation, the optical disc 4 is loaded.
It is determined whether the rotation direction of the optical disk 4 is appropriate, and if the rotation direction of the optical disk 4 is not appropriate, the optical disk 4 is reversed, so that the spiral direction of the recording track formed on the optical disk 4 is determined. The data recording/reproducing operation by the optical pickup device 5 can be performed appropriately regardless of whether the values are the same on both sides of the optical disc 4 or different on both sides.

Incidentally, in the above-described embodiment, the case where the present invention is applied to an optical disk drive device has been described, but the present invention can be similarly applied to a magneto-optical disk drive device.

Furthermore, in the above-described embodiment, a case was explained in which one optical pickup device was provided, but the present invention also applies when two optical pickup devices are used to independently record/reproduce data on both sides of an optical disk. The invention can be applied in a similar manner.

Furthermore, the present invention can be similarly applied to servo data formats other than those of the above-described embodiments. Further, the present invention can be similarly applied to an optical pickup device whose optical system is different from that of the above-described embodiment.

[0062]

[Effects of the Invention] As explained above, according to the present invention,
Since the rotational direction of the optical disc is determined when starting to use the mounted optical disc, the effect is obtained that even a recording surface on which a recording track in a reverse spiral direction is formed can be appropriately accessed.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an optical disc drive device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of an optical system of an optical pickup device.

FIG. 3 is a schematic diagram showing an example of servo data.

FIG. 4 is a block diagram showing an example of a main part of a control system of the device shown in FIG. 1;

FIG. 5 is a flowchart showing an example of control of the device in FIG. 4;

[Explanation of symbols]

1 Spindle motor 4 Optical disk 29 Tracking error detection section 30 PLL (Phase Locked Lo
op) Circuit 31 Timing generator 32 Control unit 34 Amplitude detector 37 Spindle motor drive unit

Claims (2)

[Claims] Claims: 1. An optical disc device that detects a tracking error based on a difference in detection level between two wobble pits of an optical disc in which a servo bite consisting of two wobble pits and one clock pit is arranged, which is capable of forward and reverse rotation of the optical disc. The synchronization of the optical disk rotating means, the amplitude detecting means for detecting the amplitude of a tracking error signal representing a tracking error, the clock forming means for forming a reference clock signal synchronized with the clock pit detection timing, and this clock forming means is completed. An optical disc device comprising control means for inputting a detected value of the amplitude detecting means at the time when the amplitude detecting means has reached a predetermined value, and for reversing the rotational direction of the optical disc by the optical disc rotating means when the detected value does not reach a predetermined value. 2. A control method for an optical disc device in which a tracking error is detected based on a difference in detection level between two wobble pits of an optical disc on which a servo byte consisting of two wobble pits and one clock pit is arranged. When the synchronization of the reference clock signal with the detection timing is completed, the amplitude value of the tracking error signal is detected, and if the detected amplitude value is not a predetermined value, the rotation direction of the optical disc is reversed. A method for controlling an optical disk device.