JPH0244576A - Optical disk - Google Patents

Abstract

PURPOSE:To improve the retrieval accuracy of an optical beam to a purpose track together with the reliability of address information reproducing by recording the address information of respective sectors on a circular arc track, which is formed with the optical beam, at the time of track retrieval. CONSTITUTION:Recording tracks of an optical disk 1 are divided into sectors 3. A sector address 4 is formated and recorded so as to be coincident with the circular arc track, which is formed by the optical beam, at the time of the track retrieval. Accordingly, the retrieval is executed samely as a linear moving type and the reliability of the reproducing sector address is improved. Then, the retrieval accuracy is improved for the optical beam to the purpose track on the basis of a track crossing number.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical disc on which information is recorded, reproduced, or erased using a light beam, and specifically relates to an optical disc with an improved format. .

[Conventional technology]

In optical discs for information processing, the recording track is divided into units called sectors to match the size of the data unit processed by a computer, etc., so that information can be recorded, reproduced, or erased efficiently. It is customary to use. Additionally, each of the above sectors includes:
The address representing the first sector is formatted in advance, and the address is set to G1 before processing each sector information.
1ff is now possible.

In FIG. 4(a), the optical disc 11 is CAV (C.

n5LanL An(Huler Vel
This figure shows an example of a format for address information generally used when the optical disk is rotationally driven using the optical disc 11, in which each recording track 12 on the optical disk 11 is divided into the same number of sectors 13... , each sector 1
A sector address 14 is preformatted at the beginning of the optical disk 11, and the recording positions of the sector addresses 14, .

On the other hand, the optical disc 11 having such a format
An optical recording/reproducing bag rIf, 15 as shown in FIG. ing. This optical recording/reproducing device 15
The optical head 17 includes a motor 16 for driving the optical disk 11 by CAV, an optical head 17 equipped with a recording/reproducing/erasing means using a light beam (not shown), and precision positioning means such as a tracking means and a focusing means.
It is comprised of a feeding device 18 that transports the optical disc 11 in the radial direction, a signal processing circuit 19 that processes the reproduced signal obtained by the optical disc 17, and a control device 20 that controls these.

To control the positioning of the light beam in the optical recording/reproducing device 15, address information is obtained by the reproducing means of the optical head 17 and the signal processing circuit 19, and the current position of the light beam is detected. Next, after the control device 20 calculates the distance from the current position to the position where the target sector exists, the optical head 1
Trough 7: At the same time as stopping the operation of the tracking means, the feeding device 18 is made and activated to scan the optical beam in the radial direction of the optical disk 11, and roughly position it in the vicinity of the track having the target sector. Note that such positioning control is generally performed by detecting the moving speed and movement (2) of the optical radar 17. Next, the tracking means and reproducing means of the optical head 17 and the signal processing circuit 19 are operated to detect the address of the track at the rough determined position, and calculate the error from the target track to track the optical head 17. Precise positioning control is performed to move the light beam onto the target track by means of the jumping means attached to the means and the feeding device 18. After guiding the light beam onto the target track, the sector address is reproduced, and when the target sector rotates, the positioning operation is completed and the next predetermined operation such as recording, playback, or erasing is started. It turns out.

Incidentally, in recent years, with the aim of increasing the speed and precision of the above-mentioned positioning operation, the optical head 17 has become smaller and lighter, and the mechanism of its feeding device has also changed. An example of this is shown in FIG. 6, and this feeding device 18' is not of the linear movement type described above, but of a rotational movement type, and has a rotating arm 2 centered around point Q.
A light beam irradiated from a light beam 17 disposed at the tip of the optical disc 11 moves across the track of the optical disc 11 in an arc shape.

In addition, improvements have been made to the control method for direct positioning to the target track.
The amount of movement of the light beam can be obtained with high accuracy by detecting up-down signals output each time the track on the optical disk 11 is traversed and counting the number of tracks traversed.

Here, a case will be considered in which the optical disc 11 formatted as described above is used for the above-mentioned feeding device 18'. FIG. 7 shows the passage of time when a positioning control operation is executed by counting the number of tracks crossed, and FIG. )(c) is address information reproduction signal B
-B', (d) and (e) of the same figure are the track crossing signals c-c' of the optical beam, and (f) of the same figure is synchronized with the format and rotation of the optical disk 11 based on the point where the predetermined address information exists. The address position prediction signals obtained using the quasi-clock are shown respectively.The signals B' and C
' is a signal for a type in which the optical head 17 moves linearly, and is shown for comparison with a rotating type. As shown in FIG. 5A, before the optical head 17 starts moving (before point 8 in the figure), it is in a state where a desired track is being tracked by normal tracking operation. Therefore, both address reproduction signals B and B' are reproduced normally, and the address reproduction position coincides with the predicted point of the address position prediction signal. Also, the track crossing signal c-c' does not change since it does not cross the track.

On the other hand, during the movement of the optical head 17 (from point S to point E in the figure), the moving speed signal A of the optical head 17 reaches approximately the midpoint according to the acceleration/deceleration control of the feeders 18 and 18'. The shape has the maximum velocity. Since the light beam does not necessarily scan the address while moving, the address reproduction signal B-B' is different from the reproduction output when the track is captured. The track crossing signal c-c' is a signal that repeats two signal levels corresponding to each on the track and between the tracks each time the optical beam 11 crosses the track. In the second signal c-c', the part where the signal is disturbed is when the light beam crosses the address, as shown in Fig. 4(b).
), this occurs because the shapes of the sector 13 portion and the sector address 14 portion are different.

The position control of the optical head 17 is performed using a track crossing signal c - c
However, when the signal c-c' is binarized, an erroneous detection pulse is generated, leading to an error in counting the number of track crossings. Therefore, the above-mentioned counting errors are suppressed by using an address position prediction signal. Specifically, the valid period of the address position prediction signal (Low Lev in the figure)
In part e1), the counting operation is interrupted, and the count is corrected by adding or subtracting the number of track crossings during the interruption period by the count number in a predetermined period preceding or following the interruption period.

In this case, the interval between the address reproduction point in the signal B' and the disturbance point in the signal C' when the optical radar 17 moves in a straight line is constant and coincides with the predicted point of the address position prediction signal. , the above-mentioned count correction operation will be performed normally.

[Problem to be solved by the invention]

However, when the optical head 17 rotates, the address reproduction point in the address reproduction signal B and the disturbance point in the track crossing signal C are different from the pre-Z point in the address position prediction signal. This timing shift occurs because the optical head 17 also moves in the track direction due to rotation, and in FIG. 6, the light beam moves from the innermost track to the outermost track. When moving to a track, the maximum amount of deviation occurs when the light beam is located at the midpoint.

Therefore, when the rotating optical head 17 is used for the optical disc 11 formatted as described above, even if the track count correction operation is performed, miscounts cannot be sufficiently suppressed. This results in positioning on the wrong track, resulting in the problem that it becomes difficult to increase the speed and accuracy of the positioning operation.

[Means to solve the problem]

In order to solve the above problems, an optical disc according to the present invention is an optical disc in which a recording track scanned by a light beam is divided into a plurality of sectors, and address information indicating the address of each sector is recorded. 2, the recording position of the address information is formatted so that when the light beam searches for a track, it matches an arcuate locus.

[For production]

According to the configuration described in 2, it is possible to perform a high-speed and highly accurate track search.When an optical head is sent by a rotary type feed device, no matter which recording track the light beam is positioned on, the address reproduction signal is The intervals between the address reproduction points and the disturbance points in the track crossing signal are constant, and the address position can be predicted using a simple address position prediction signal used in a linear movement type. Therefore, the reliability of address information reproduction can be improved, and the count correction operation can be performed accurately in positioning using the number of tracks crossed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

As shown in FIG. 1, in the optical disc l according to the present invention, each recording track 2 scanned by a light beam is divided into the same number of sectors 3. A sector address 4 in which address information indicating the address is recorded is formatted in the part. The sector address 4... is the relationship between the light beam rotation radius and the rotation center position of the optical disc 1 in a rotary feeder (not shown) of an optical recording and reproducing apparatus that actually records, reproduces, or erases information. Formatting is performed at the points where the movement locus X of the light beam on the optical disk 1, which is determined by the relative positional relationship, intersects with each track 2. In other words, the positions of sector addresses 4, . . . coincide with the arcuate loci drawn by the light beam when searching for tracks 2, .

According to the above configuration, when the optical head is sent by a rotary type feeder that enables high-speed movement, address reproduction is possible regardless of whether the optical head is located on °ζ, optical beam 1, or recording track 2... The intervals between the address reproduction points in the signal and the disturbance points in the track crossing signal are constant, and the address position can be predicted using a simple address position prediction signal such as that used in a linear movement type feeding device. Therefore, the reliability of address information reproduction can be improved, and
Count correction operation can be performed accurately in positioning using the number of tracks crossed.

Here, as a method for specifying the recording position of the sector address 4, etc., there is a soft formatting method normally used for magnetic floppy disks, etc. In other words, only the recording track position is specified in advance, and the sector address etc. The formatting method used by the optical recording and reproducing device itself, and ■
There is a method in which both the recording track and the sector address are preformatted in a preformat device like a normal disk.

In the method (2) above, the light beam and recording 1-rank 2
Since the relative positional relationship with . In addition, Fig. 2 (a
), the signal CK is a V clock signal having the same frequency as the rotation period of the optical disk l driven by the CAV. In addition, in (1) of the same figure, the signal FS is a signal indicating the timing when recording an address, and the signal FS is a signal indicating the timing when recording an address, and
The clock signal CK is output every time a predetermined number of clock signals are counted. That is, when formatting n sectors on one track under synchronized conditions such that the time per revolution of the optical disc 1 corresponds to N reference clock pulses, N/n reference clock pulses are used. A signal FS is output every time the signal F is counted.
Address formatting can be performed by using S as a trigger to modulate the intensity of a light beam that sequentially follows a recording track based on address information.

In addition, even in the method (2), the optical head feeding device installed in the formatting device is of a rotating type, and the light beam rotation trajectory of the optical head feeding device is of a rotating type, so that the light beam rotation trajectory of the optical recording and reproducing device matches. If the address format is configured as follows, the address format can be created in the same manner as the above-mentioned method (2).

On the other hand, the optical head feed device installed in a formatting device is a linear movement type and the light beam draws a straight trajectory, while the optical head feed device in an optical recording/reproducing device is a rotation type and the light beam rotates. In the case of a device that draws a trajectory, as shown in Fig. 3, a straight line is formed by connecting the intersection of a circular arc drawn with a format radius R and a circular arc drawn with a light beam rotation radius r of ii+7 with the center point of the optical disk. ffl and the virtual linear trajectory 12 drawn by the linearly moving type light beam, the recording start point of the address formant is sequentially corrected by a time corresponding to the included angle Δθ from a reference gate signal obtained from a reference rotation synchronization signal or the like. By doing this, a desired arc-shaped format can be obtained. Note that the correction amount can be easily calculated using the rotation center of the optical disk, the rotation center of the optical head, and the format - radius R.

[Effects of the Invention] As described above, the optical disc according to the present invention is an optical disc in which a recording track scanned by a light beam is divided into a plurality of sectors, and address information indicating the address of each sector is recorded. In this configuration, the recording position of the address information is formatted so as to match the arcuate locus drawn by the light beam when searching for a track.

This not only makes it possible to accurately count the number of tracks traversed to detect the position of the light beam when sending the optical head using a rotary feeder that enables high-speed and highly accurate track searches, but also allows for accurate tracking during the search. It is also possible to reproduce and recognize address information using an address position prediction signal that matches the sector address position, and furthermore, there is also the effect that search control for making the light beam reach the target track can be performed with high precision.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, in which FIG. 1 is a conceptual diagram showing the formant of an optical disc, FIG. 2(a) is a time chart showing a reference clock signal, and FIG. Figure (b) is a time chart showing timing signals, Figure 3 is an explanatory diagram showing a method of forming an arcuate address formant in a formatting device equipped with a linear movement type feeder, and Figure 4 is a conventional example. Fig. 5(a) is a conceptual diagram showing the format of an optical disc, Fig. 5(b) is an enlarged view of the part indicated by the Z arrow in Fig. 5(a), and Fig. 5 is a schematic configuration of the optical recording/reproducing device. 6 is an explanatory diagram of the rotary type feed device, and FIG. 7 is a diagram showing the time course when positioning control operation is executed by counting the number of track crossings. ) are the moving speed signals of the optical head, (b) and (c) are the address information reproduction signals, (d) and (e) are the optical beam cross-track signals, and () are the address information. 1 is a time chart showing position prediction signals. 1 is an optical disk, 2 is a recording track, 3 is a sector, and 4 is a time chart showing a position prediction signal.
is the sector address. 20' No. 212I (b) To' - Kazuichi Ikkita

Claims (1)

[Claims] 1. In an optical disc in which a recording track scanned by a light beam is divided into a plurality of sectors and address information indicating the address of each sector is recorded, the recording position of the address information is , an optical disc characterized in that the optical disc is formatted so as to match the arcuate locus drawn by the light beam when searching for a track.