JPS6159673A - Track accessing method and optical disk of optical disk device - Google Patents

Abstract

PURPOSE:To access at a high speed and surely a target track by dislocating an ID mark in the connecting line direction of respective tracks, recording it to an optical disk, shifting an optical head by only a distance of the difference between a present position and by a target track position and detecting a target track from a rotating angle from a base point of the ID mark. CONSTITUTION:An ID mark is dislocated in the connecting line direction of respective tracks to an optical disk 10 and recorded to an ID mark recording part A. A present position of an optical head is judged from a track address in the ID mark which is read from the optical disk 10, the optical head is shifted only by the distance equivalent to the difference between a target track position and a detected present track position, a rotating angle from a base point C of the ID mark is detected, then a target track is detected. Thus, the target track can be accessed with high speed and surely.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention records ID marks indicating track addresses, etc. on a large number of concentric or spiral tracks, and detects the ID marks to identify a predetermined address. The present invention relates to a track access method applied to an optical disk device for recording data on and reading recorded data, and an optical disk used directly to implement this method.

(Technical Background of the Invention and Prior Art) Data is recorded by detecting ID marks indicating addresses recorded in advance on concentric tracks.

There is an optical disc device that performs playback. In this case, an optical head for writing and reading data.

It is necessary to quickly move to the track containing the target data 2 (target track).

In conventional optical disc devices, ID marks for each track are arranged radially on a line passing through the center 2 of the optical disc, and after the optical head P moves from the current track position of the optical head to near the target track position, the contents of the ID marks are read. Read that track? identify.

If the optical head does not match the target track, the optical head is moved to the target track position again, and the same process is repeated until the optical head finally reaches the target track. That is, it was necessary to read out the contents of the 10 marks several times and correct the optical head position. Also, it takes time for the optical head to read and judge the ID mark from the optical disc.
Furthermore, in consideration of ID mark writing errors, etc., several I
It is necessary to check the D mark. In this way, conventionally I
Since the head position was corrected by reading out the content 3 of the D mark, there was a problem in that it took a long time for the head to access the target track.

(Purpose of the Invention) The present invention has been made in view of the above circumstances (see the margin below), and it is possible to shorten the track access time of an optical disk device, and to provide a fast and reliable 7M access to light to a target track. The purpose is to provide a track access method that allows.

Furthermore, the present invention provides an optical disc that is directly used to implement this track access method. For other purposes.

(Structure of the Invention) According to the present invention, the object is to provide an ID for indicating a track address, etc., to each of a plurality of tracks forming a track group.
Marks are previously recorded on the optical disc while being shifted in the tangential direction of each track.

The optical head is moved by a distance corresponding to the difference between its target track position and the current track position, detects the rotation angle position from the base point of the ID mark, and detects the target track from the detected rotation angle position. This is achieved by a track access method for an optical disc device characterized by the following.

The other purpose is to form a track group by a plurality of adjacent tracks, track addresses, etc. This is achieved by an optical disc characterized in that an ID mark for indicating the present invention is recorded at a tangentially shifted position on each track in the track group.

In the present invention, the tracks may be concentric or spiral. Further, the track may have a guide groove such as a group, or may not have a guide groove.

(Actual IM mode) The present invention will be described in detail below based on the drawings.

FIG. 1 is a perspective view including a partial sectional view of an optical disc device which is an IM embodiment of the present invention, FIG. 2 is a partial plan view of the same optical disc, and FIG. 3 is a partially enlarged view thereof. Furthermore, the second
In the figures and FIG. 3, the relative positions of the ID marks 2 are shown far apart, but it goes without saying that they are actually recorded at a high density.

In FIG. 1, reference numeral 10 is an optical disc.

For example, a metal may be deposited on one side of a transparent substrate such as glass, and this deposited layer may be corrugated with a protective layer. It goes without saying that various types of optical discs can be used as optical discs, such as discs with concentric or spiral tracks, discs with or without guide grooves, and discs with various recording and reproducing methods. can be used. This optical disc 10 is rotated at a constant speed by a drive motor (not shown).

Reference numeral 12 indicates an optical system for recording and reproducing, and this optical system 12 is operated by a tracking error motor 14 to read the optical disc 10.
A radially movable base 16 and a semiconductor laser 18° beam splitter 20 placed on this base 16.
1 Reflector 22. Optical head 24°, photodetector 26, etc.? We are prepared. A position detector 28 detects the amount of movement of the base 16. In the optical head 24, an objective lens is attached to the optical disk 1.
a focus servo mechanism that moves in a direction perpendicular to zero;
A tracking servo mechanism for moving the objective lens in the radial direction of the optical disc 10 is built-in. lasere 8
The focus of the light is controlled so that it is focused from the optical head 24 onto the recording surface of the optical disc 10.

The light reflected from this recording surface passes through the beam splitter 20 and is detected by the photodetector 26. Based on the output of the photodetector 26, a focus error, a tracking error, and a digital signal on the recording surface are detected. Note that this focus error drives a focus servo mechanism built into the optical head 24.

Further, the tracking error is divided into, for example, a low frequency component and a high frequency component, and the configuration is such that the low frequency component drives the tracking servo motor 4, and the high frequency component drives the tracking servo @M built in the optical head 24, respectively. .

A large number of ID mark recording sections A are provided on the optical disc 10, for example, along concentric tracks.

An ID mark is recorded here in advance. This ID mark is information for identifying data to be recorded or reproduced, and includes a track address number to indicate track 3, and may also include a sector address. Preferably, a mark indicating the start of a sector is recorded at the beginning of the ID mark.

On each track, n is an integer.

■= An ID mark is recorded in advance for each rad, and an ID mark is recorded in advance for each rad. A data recording section B is formed.

ID marks on each track are arranged as follows. That is, first, one track group is formed by N adjacent tracks. A predetermined angular position on the optical disk 10 is determined as a second base point C, and an ID mark on the outermost track of each trunk group is placed at this base point C. The ID mark on the inner track is placed so as to start from a position shifted from this base point C by θ=1−2 nN. The ID mark on each track is thus sequentially tangentially oriented at an angle O.
It has been recorded in advance.

Next, the order in which predetermined data is accessed in order to record and reproduce data will be explained. first.

The current position of the optical head 24 is determined from the track address in the ID mark read from the optical disk 10. Next, a distance corresponding to the difference between the target track position and the detected current track position is determined, and the optical head 24 is moved by that distance. move it.

Since the optical disc 10 always has concentricity and other errors,
Since the optical head cannot be positioned on the target track by this alone, a tracking servo mechanism is generally operated to follow the track.

On the other hand, the rotation angle of the optical disc 10 is always detected by appropriate means. For example, a position plan corresponding to the base point C,
The rotation angle of the wound disk 10 can be determined by detection using a combination of a notch provided in the optical disk 10, a light source, and a photodetector. Also, for each angle ■ from base point C.

Another notch that can be distinguished from this base point C is provided.

The rotation angle may be detected using the ID mark on the outermost circumference of each track group and a new base point.

In this way, since the angle 11 of the optical disk 10 based on the position e of the outermost ID mark of each track group is constantly detected, the optical head 24 that has moved near the target track position Once detected, the rotation angle α at the time of detection is determined. This rotation angle α corresponds to one track within each track group. That is, if it is the outermost track of the track group.

α=0 If it is the mth track from the outermost track.

This is because. Therefore, if it is the m-th track in the first track group from the outer circumferential side of the optical disc lo, it can be determined that it is the 1-N+m-th track from the outer mat of the optical disc 10. Note that the fact that it is the first track group is detected by a position detector or the like when the optical head moves. Furthermore, the number of the current track in the track group is always detected.

In this way, the target track is determined from the rotation angle position of the ID mark. At this time, the trunking servo is operated to position the optical head 242 on the target track. And is it the sector of the target address based on the contents of the ID mark on this target track or the rotation angle from the base point C? The data is detected and data is recorded or read in the data recording section B.

The truck address is written on the ID mark,
Since the sector address can be detected by the rotation angle from the base point C, one sector address may or may not be recorded. Although the target track is determined based on the rotation angle, the track address in the ID mark may be read out for double checking.

Note that in the present invention, the width of the track group is equal to the width of the optical disc 1.
It is desirable to set the amount of eccentricity so that it is always larger than the amount of eccentricity of 0. In this case, when moving the optical head 24 by a distance corresponding to the difference between the current track position and the target track position of the optical head 24, the optical head 24 may be moved near another track that is shifted by N or more lines from the target track. There is no risk of movement, and track access time is further shortened.

It is clear that the invention is not limited to the embodiments described above.

(Effects of the Invention) As described above, the present invention records data in advance in a tangential direction for each track forming a two-track group of ID marks, and quickly tracks the target track based on the rotation angle position from the base point of the ID mark. Please judge.

Therefore, the I of each track and rack should be placed on a line passing through the center of the optical disc.
Compared to a conventional device in which D marks are arranged radially, which detects the target track number while repeatedly determining the recorded contents of the ID mark, the present invention has the advantage that the track access time can be shortened. Also, by reading the track address or sector address from the ID mark,
Since the track or sector can be confirmed not only by the rotation angle but also by the read track address or sector address, a more reliable track access method is possible.

[Brief explanation of the drawing]

FIG. 1 is a perspective view including a cross-sectional view of a portion of an optical disk device according to an embodiment of the present invention, FIG. 2 is a plan view of a portion of the optical disk, and FIG. 3 is a partially enlarged view thereof. 10... Optical disc, A... ID mark recording section. B...Data recording section, C...Base point. D...New base point.

Claims (5)

[Claims] (1) In a method of track accessing an optical disc using an optical disc device, on which ID marks indicating track addresses, etc. are pre-recorded with tangential shifts on adjacent tracks, the optical head of the optical disc device is moved from the current position to the target track. 1. A track access method for an optical disc device, characterized in that a target track is detected by moving the ID mark of the track to a base point of the optical disc and detecting a rotation angle of the ID mark of the track from a base point of the optical disc. (2) A track access method for an optical disc device according to claim 1, wherein the tracks are concentric circles. (3) A track access method for an optical disc device according to claim 1, wherein the track has a spiral shape. (4) A track group is formed by a plurality of adjacent tracks, and an ID mark indicating a track address etc. is recorded at a position shifted in a tangential direction on each track in the track group. optical disk. (5) The optical disc according to claim 4, wherein the width of the track group is larger than the eccentricity of the optical disc.