JPS6366734A - Optical disk device - Google Patents

Abstract

PURPOSE:To use a land and a groove as an information track and to increase theoretically a memory capacity to double by track servo-controlling a beam spot to the both of land and groove. CONSTITUTION:A track servo circuit 3' inverts a tracking polarity according to a tracking polarity specified signal SW to make it the track servo and a control part 4 supplies the tracking polarity specified signal SW to the rack servo circuit 3' according to whether the track to be accessed is a groove or a land. By inverting the tracking polarity of the track servo, in the land 10 and the groove 11 the beam spot BS can be followed in track. Thus if the tracking polarity of the track servo circuit 3' is inverted any of the land 10 and the groove 11 can be used as the information track so as to increase the memory capacity, because the beam spot BS can be guided to both the land 10 and the groove 11.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Conventional technology Problems to be solved by the invention Means for solving the problems (Fig. 1) Working example (a) One embodiment Explanation (Figures 2 and 3) ('b)
Description of other embodiments Effects of the invention [Summary] For an optical disk having groups and lands.

In an optical disk device in which the beam spot of an optical head is track-followed by a track servo circuit, by configuring the tracking polarity of the track servo circuit to be variable, the beam spot can be guided to both the group and the land, and the beam spot can be guided to both the group and the land. It is used as an information track to increase storage capacity.

[Industrial application field]

The present invention relates to an optical disk device such as an optical disk or a magneto-optical disk, and more particularly to an optical disk device in which both groups and lands of a disk can be used as information tracks.

2. Description of the Related Art Optical disk devices using optical disks or magneto-optical disks are widely used as storage devices that can perform recording/reproduction using minute laser spot light.

This is because such optical disc devices can record/reproduce at a track pitch of several microns.

It is possible to increase the storage capacity, and various efforts are being made from various fields to further increase the storage capacity.

[Conventional technology]

The optical disc 1 of the optical disc device has a group 1 and a land 10 formed thereon as shown in FIG.
0. The concave portion is defined as group 11.

In conventional optical disk devices, land recording is performed in which land 10 is used as an information track and recording bits RB are written/reproduced on land 10, as shown in FIG. Group recording has been known in which recording bits (RB) are written/reproduced in group 11 using the RB as a track.

In an optical disk device, as shown in FIG.

A beam spot B is placed on the track of the optical disk 1 by an optical head 2 that can move the beam spot B in the radial direction.
At the same time, the optical head 2 receives the reflected light from the optical disk 1, and the track servo circuit 3 issues a track servo signal TSS to the optical head 2 based on the output of the received light. A tracking servo is used that moves the beam spot BS in the radial direction to make the beam spot BS follow the track. This tracking servo uses the interference of light due to the unevenness of the optical disc 1, which is the group 11 and the land 10, to determine the tracking error.

Therefore, for land recording, the beam spot BS was configured to perform tracking servo with land 10 as the track), and conversely, for group recording, the beam spot BS was configured to perform tracking servo with group 11 as the track. .

[Problem that the invention seeks to solve]

In this way, in the prior art, land 10 or group 1
Use only one side of 1 as the information track.

Tracking servo was possible for one of the information tracks.

For this reason, group 11 is used as an unused track in land recording, and land 10 is used as an unused track in group recording, making it difficult to increase the storage capacity.

An object of the present invention is to provide an optical disc device that can increase storage capacity by using both groups and lands of an optical disc as information tracks. It is a diagram explaining the principle of the invention.

In the figure, the same parts as shown in Figures 4 and 5 are:
3' is a track servo circuit with variable tracking polarity, which performs track servo by changing the tracking polarity in response to a tracking polarity designation signal SW, and 4 is a control unit, which is an access circuit. A tracking polarity designation signal SW is given to the track servo circuit 3' depending on whether the track to be tracked is a group or a land.

[For production]

The track servo is activated by crossing the tracking polarity [, beam spot B on land 10 and group 11]
Therefore, if the tracking polarity of the track servo circuit 3' is changed, the land 10.S can be made to follow the track. Beam spot BS can be guided to either group 11.

Both lands 10 and groups 11 can be used as information tracks, increasing storage capacity.

〔Example〕

FIG. 2 is a configuration diagram of an embodiment of the present invention.

In the figure, the same things as shown in FIGS. 1, 4, and 5 are indicated by the same signals. , la is a spindle motor with 99 rotation axis 1b as the center.

A carriage moving unit 5 rotates the set optical disc 1, and a carriage moving unit 5 moves the carriage on which the optical head 2 is mounted and positions it at a desired track position, and includes a reel, a motor, and a motor control unit. be.

The optical head 2 converts light emitted from a semiconductor laser 20, which is a light source, into a lens 21. Beam splitter 22° 1/4λ wavelength plate 23. Recording/reproduction is performed by irradiating light onto the optical disc 1 through the mirror 24 and the objective lens 25, and the reflected light from the optical disc 1 is transmitted through the objective lens 25. Mirror 24, 1/4λ wavelength plate 23. The light is received through the beam splitter 22, and a reproduction (RF) signal is obtained from the photodetector 28 through the lens 27 through the half mirror 26.

It is configured so that a track error signal and a focus error signal can be obtained from a four-split photodetector 29 via a half mirror 26. 25a is a lens moving mechanism;
0 is a track error detection circuit, and a 4-division photodetector 2
From the output of 9, a track error signal TE is generated by the method described later.
8, 31 is an inverting amplifier, 32 is an inverter circuit, 32 is an inverter circuit, and 33 is a switch (gate). ).

It is opened by the tracking polarity designation signal SW and outputs a track error signal TE8 which is inverted by two.

34 is a switch (gate) that is opened by the inverted tracking polarity designation signal SW 11 and outputs the track error signal TE8; 35 is a phase compensation circuit that outputs the track error signal T which is the output of the switch 33 or 34;
A power amplifier 36 performs phase compensation for the BS and TES, amplifies the output of the phase compensation circuit 35, provides a track servo signal TSS to the lens moving mechanism 25a of the optical head 2, and moves the objective lens 25 as shown in the figure. It is for moving in the left and right (radius of the optical disc 1) direction.The control unit 4 is composed of a microprocessor.

Rotation control of the spindle motor 1a, light emission control of the optical head 20 and semiconductor laser 20, movement control of the carriage moving unit 5, analysis of access instructions, photodetector 28 of the optical head 2
Therefore, either the switch 33 or 34 is selected by the tracking polarity designation signal SW of the control unit (hereinafter referred to as MPU) 4. , whereby the track servo signal T8S becomes the 2-inverted track error signal T.
It is created based on either ES or track error signal TBS.

FIG. 3 is an explanatory diagram of the operation of one embodiment of the present invention.

The MPU 4 controls the spindle motor 1a at a constant speed.

The original disk 1 is rotated at a constant speed. Land 10 of optical disc 1. Track addresses are assigned to the groups 11 in the order in which they are arranged.

When the MPU 4 receives an access instruction from a host computer or the like, it performs a seek operation according to the track address to be accessed. If the least significant bit of the track address is associated with a land or group, the tracking polarity designation signal SW is generated depending on the least significant bit of the track address.

For example, if the least significant bit is a land, the designation signal SW is set low (“0”), thereby opening the switch 34 via the inverter circuit 32 and outputting the track error signal TBS to the phase compensation circuit 35.

At the same time, the carriage moving unit 5 is instructed to move the optical head 2 to the position corresponding to the track address.

Track servo control is as shown in FIG. 3 (5).

Depending on the position of beam spot B8 with respect to the desired track (land 10 in the figure), the light intensity distribution of the reflected light changes to land 10.
Track errors are detected by utilizing changes caused by light interference caused by the unevenness of the group 11 and the group 11, and the distribution of light received by the 4-split photodetector 29 depends on the position of the beam spot BS and the track 10. Depending on the relationship, it changes like the third position.

Therefore, when the track error detection circuit 30 takes the difference between the left and right areas in the figure on the light receiving surface of the 4-split photodetector 29, as shown in FIG.
As shown in B), when the positions of the track 10 and the beam spot BS are coincident, the track error signal TBS becomes zero (2), and when it deviates to the left or right, a positive or negative track error signal TBS (2) or (4) is obtained accordingly.

Since the track servo signal T8S outputs a servo signal directed toward the 0 point when the track error signal TE8 is in the range 8A in the figure as shown in FIG. 3(B), the lens moving mechanism 25a A servo is applied so that the beam spot BS is directed toward the center of the land 10, that is, toward the zero point of the track error signal TE8.

As a result, the beam spot BS performs a track following operation using the land 10 as a track.

Therefore, recording/reproducing to land 10 becomes possible. On the other hand, if the least significant bit is a group, MPU 4 sets the designated signal SW to high ("1"), thereby opening switch 33 and causing 1 inversion track error. The signal TE8 is outputted to the phase compensation circuit 35.

2 inverted track address number TBS as shown in Fig. 3 β)
When BS is emitted, a servo signal TSS directed toward the 0 point is emitted for the output in the range of 8A in Figure 1, so the track servo signal T8S causes the lens moving mechanism 252 to detect the beam position (BS) at the center of group 11, that is, the track error. The servo is applied so that the signal TBS moves toward the 0 point.

As a result, the beam subsystem BS performs a track following operation using group 11 as a track.

This allows recording/reproduction to group 11.

In this way, by simply changing the tracking polarity of the track servo circuit 3', group 11. The beam spot of the optical head 2 can be controlled to follow the tracks by using both lands 10 as information tracks.

('b) Description of other embodiments In the embodiment described above, track addresses are sequentially attached to group 11 and land 10, and the lowest pit of the track address is made to correspond to a land and a group. Each section has a different volume name, and is handled as if it were a double-sided medium.

The tracking polarity may also be specified by specifying the volume name.

Further, although the explanation has been given using an optical disk as an example, the application may also be applied to a magneto-optical disk, and the optical head 2 is not limited to the optical head 2 of the embodiment, but may be any other well-known optical head 2 such as a 3-beam system. You can.

Furthermore, not only a single-sided disk but also a two-sided disk may be used, and the track servo circuit may also be of other types.

Although the present invention has been described above with reference to embodiments, the present invention can be modified in various ways according to the gist of the present invention.

These are not excluded from the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, since the beam spot can be track servo controlled for both lands and groups, the lands and groups can be used as information tracks, and the storage capacity can theoretically be doubled. It has the effect of being able to

Furthermore, since this can be realized by simply adding a simple electric circuit to the track servo circuit, it is also possible to increase the storage capacity easily and at low cost.

[Brief explanation of the drawing]

Figure 1 is a detailed explanation of the present invention. FIG. 2 is a configuration diagram of an embodiment of the present invention. FIG. 3 is an explanatory diagram of the operation of one embodiment of the present invention. FIG. 4 is an explanatory diagram of the prior art. FIG. 5 is a block diagram of the prior art. In the figure, 1... optical disc. 2...Optical head. 3.3'...Track servo circuit. 4...Control unit. 10...Rand. 11...Group.

Claims (1)

[Claims] An optical disc (1) having a group (11) and a land (10), an optical head (2) capable of moving a beam spot in the radial direction of the optical disc (1), and the optical head ( 2) an optical disc device comprising: a track servo circuit (3) for controlling the beam spot of the optical head (2) to follow the track of the optical disc (1) according to a track error signal obtained from the received light output; The track servo circuit (3) is configured with a track servo circuit (3') whose tracking polarity is variable, and control is provided to provide a tracking polarity designation signal to the track servo circuit (3) depending on whether the track to be accessed is a group or a land. An optical disc device characterized in that a group (11) and a land (10) of the optical disc (1) are used as an information track.