JPH02152073A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent a retrieval error with minimum constitution by retrieving an objective track based on such a number of tracks as a special number of tracks added to a difference between an address of a present track and an address of the objective track. CONSTITUTION:A prescribed track is accessed by an optical head 18 with a linear motor 19, and a track address is read out by a controller circuit 28 with an index information read circuit 26. A setting value is obtained in the circuit 28 by adding the difference between the present track address and the objective track address to a number as a multiplication of a number of group boundaries between the present track and the objective track by the number of the special tracks. Then, a linear motor driving circuit 20 is set at this setting value, and the objective track is retrieved by moving the motor 19. By this method, the retrieval error owing to the special track is prevented with minimum constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a recording/reproducing Vi device using an optical disk.

Conventional technology Computer processing of large amounts of information such as information on both images is progressing. As a device for recording and reproducing such a large amount of information, a recording and reproducing device using an optical disk is used.

Conventionally, in such optical disk recording and reproducing devices, information is recorded or reproduced using a disk whose optical axis is recorded in a spiral manner and an optical head which is moved linearly in the radial direction of this disk by a linear motor. There is.

By the way, in such an optical disk recording/reproducing device, 421
．． In order to ensure stable recording/playback and shorten access time, we use a constant rotational force type (constant rotation speed) where the disk rotational speed is constant.
CAV method: Con5tant Angular
Recording and reproduction are performed using the Velo-city system. In the CAV system, the number of sectors per track is constant on both the inner and outer tracks. Therefore, since the recording pits on the outer periphery become larger, the recording density per unit track becomes smaller, making it impossible to achieve higher density.

In addition, for high-density recording on optical discs, a linear velocity constant force method (constant linear velocity) is used, which slows down the rotational speed of the optical disc as it moves from the inner circumference to the outer circumference of the optical disc to keep the relative linear velocity between the optical nozzle and the optical disc constant. CLV method: Con5
There is a method for recording and reproducing data using the tant linear velocity method). This CLV type optical disk has the advantage of having a large recording capacity per disk (because it is necessary to change the rotation speed of the rotary motor according to the position in the radial direction), the access time becomes long. There were drawbacks.

Therefore, a method (MCAv method: Mo
durate Con5tant Ar+gular
Velocity method) has been put into practical use. In this method, the area from the inner circumference to the outer circumference of the disk is divided into a plurality of 111- groups in the radial direction, and within each group, the number of sectors on each track is constant, and between groups, one or more sectors are distributed per track. Increase or decrease the number of sectors. In this way, in the MCAV method, recording pits are grouped so that the size of the recording pits is approximately constant on the inner and outer circumferences of the disk.

On the other hand, in optical disk recording and reproducing devices, crosstalk occurs due to the tilt of the optical head or off-track.
Information about adjacent tracks may be read by mistake.

In a disk in which the number of sectors differs between groups, such as in the MCAV system, the physical positions of the index information of the sectors of the tracks of adjacent groups differ at the boundary where the groups change. Therefore, there is a problem in which the index information of adjacent tracks is erroneously reproduced due to crosstalk. To prevent this, a prohibited special track is provided at the boundary of each group on the disc, and the data on this prohibited special track is A method has been considered in which the signal of a special track is preformatted in the recording area.

Problems to be Solved by the Invention (In this way, if there are usable tracks and prohibited special tracks on an optical disk, when searching for a target track from the current track, the current track and the target track are There is a problem in that a search error occurs by the number of prohibited special tracks between the two tracks, and the search time becomes longer.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a search method that prevents search errors caused by prohibited special tracks with a minimum configuration.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention calculates the difference between the current track address and the target track when searching for the target track. The search is performed by adding up the number of special tracks in between.

That is, the tag has a spiral or concentric track, and this track is divided into a plurality of groups in the radial direction. The number of sectors per track in each group increases or decreases depending on the position in the radial direction. , each group has one or more special tracks that cannot be recorded at the boundary between the groups, and the index information at the beginning of each sector of the special track and the index information at the beginning of each sector of the recordable track are different. In a recording/playback device that uses a disc that is preformatted with flag information that allows identification and the order of one or more special tracks, when searching for a target track, the current track address and the target track address are The present invention is characterized in that the search is performed based on the number of tracks obtained by adding the number of special tracks between the current track and the target track to the difference.

Effect of the Invention By using the above-mentioned means, the present invention can eliminate errors when calculating the difference between the current track address and the target track address, and can prevent an increase in search time.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows an optical disc with a special track that is prohibited from use. The optical disc 1 has a metal film layer coated on the surface of a circularly molded substrate made of glass or plastic, for example, and groove-like tracks 2 are previously formed in a spiral shape on the surface.

This track 2 is divided into a plurality of sectors 3, and each sector 3 is composed of an index information area 4 and a data recording area 5.In the index information area 4, index information is preformatted.

This optical disc l is divided into a plurality of groups 6 in the radial direction from the outer circumference to the inner circumference, and each group 6-
1.6-2.64 . . . has two prohibited special tracks 8-1.8-2 at the boundary positions between the usable track 7 and each group 6. These prohibited special tracks 8 are preformatted with a signal 9 unique to the special track. This signal 9 is lightly processed with preformatted pits IO at equal intervals.

Figure 2 shows the structure of index information for each track. In Figure 2, 11 is a synchronization signal when reproducing index information, 12 is a signal indicating that it is an index information area, and 13 is prohibited from use. Flag information indicating that the track is a special track, 14 is index information, and 15 is a redundant part. In this way, by having the flag information 13 indicating that the track is a prohibited special track in the index information area, the usable track 7 and the prohibited special track 8 can be distinguished. In other words, the content of the flag information 13 (binary number "00" means usable track 7.211! number "Ol" means prohibited special track 8-1 on the outer circumference side; binary number "10" means inner track In the index information indicating the prohibited special track 8-2 on the side, a track address is written as a subnumber of the usable tracks 7 in order from the outer circumference to the inner circumference in the radial direction.Special track prohibited to use 8 The track address of is equal to the track address of the available track 7 adjacent to one side in the radial direction.

The third article shows an optical disk device according to the present invention. In FIG. 3, l is an optical disk drive according to the present invention, 16 is a disk motor that rotates the optical disk at a constant speed, 17 is a motor drive circuit that drives the disk motor 16, and 18 is an optical device that records and reproduces data on the optical disk I. 19 is a linear motor drive circuit that moves the optical head 18 to access a designated track; 20 is a linear motor drive circuit that drives the linear motor 19; and 21 is a laser that drives a semiconductor laser that is the light source of the optical head 18. a drive circuit, 22 a head amplifier for amplifying the signal taken out by the optical head 18; 23;
24 is a focus/tracking control circuit that controls focus and trunking of the optical head 18, a modulation circuit that modulates the write information signal, and 25 is a head amplifier 22
26 is an index information reading circuit that reproduces and reads the index information from the signal of the head amplifier 22. 27 is a clock generation circuit 528 that generates a recording/reproduction processing frequency for each group. 29 is a controller circuit composed of a CPU that controls the above components, and 29 is a data input/output circuit that controls recording/reproducing data.

The operation of the optical disk device configured in this manner will be described below. First, the optical disc l is rotated at a constant speed by the disc motor 16, and then the optical head 18 is subjected to focus control and tracking control by the focus/tracking circuit 23, and follows the track of the optical disc l. The controller circuit 28 is a sequence control system for focusing 2L and a sequence control system for trunking.
The activation control of the disk motor 16 and laser and the processing frequency of the current group are set.

Next, recording and reproducing data on the optical disc 1 will be explained. Write data is generated from the data output circuit 29 in synchronization with the recording processing frequency generated from the clock generation circuit 27. The modulation circuit 26 modulates the write data into a form that is actually recorded on the optical disk 1. Next, the laser drive circuit 21 controls the optical output of the radar of the optical head 18 using this modulation signal to record data on the optical disk 1. do. During reproduction, the head amplifier 22 outputs and amplifies the signal recorded on the optical disk 1 using the optical head 1. The demodulation circuit 25 demodulates the reproduction signal obtained by the head amplifier 22 in synchronization with the reproduction processing frequency generated by the clock generation circuit 27. This reproduction signal also includes index information in addition to the recorded data information, and the index information reading circuit 26 reads the track address from the index information in the reproduction signal.

Next, the search for the target track will be explained.

The optical head 18 accesses a predetermined track by a linear motor 19 driven by a linear motor drive circuit 20. The controller circuit 28 uses the index information reading circuit 26 to read the current track address where the optical head 18 is located. When currently on-tracking a usable track, the controller circuit 28 uses the current track address (Ta) and the target track address (Tb).
) is multiplied by the number of group boundaries between the current track and the target track (Ng) and the number of prohibited special tracks at the group boundary (Nt = 2). The setting fA (Ndl) is obtained and set in the linear motor drive circuit 20, and the linear motor 19 is moved to search for the target track. Also, if you are currently on track on a special track that is prohibited to use, the controller circuit 2
8 is the flag information 13 from the above total K(iff(Ndl))
A value (Nd2) obtained by multiplying 1ift (Nf) by 6Ji is set in the linear motor drive circuit 20, and the linear motor 19 is moved to search for the target track.

Nd1- (Tb-Ta)+ CNL*Ng)Nd2-
(Tb-Ta) +(NL*Ng)-NfAs described in detail, the present invention provides an optical system that can perform a search with a minimum configuration while preventing search errors caused by prohibited special tracks. We can supply recording and reproducing equipment.

[Brief explanation of the drawing]

FIG. 1 is a plane showing an example of the structure of an optical disc. FIG. 2 is a schematic diagram showing an example of the structure of index information preformatted into tracks. FIG. It is a configuration block diagram. l...Optical disc length 2...Track, 3...Sector 4...Index class information area, 6...Group, 7...Usable track, 8...Special track prohibited from use, 18... Optical head, 26... Index information reading circuit, 28... Controller circuit. Name of agent: Patent attorney Shigetaka Awano One idiot Figure 1

Claims (2)

[Claims] (1) It has a spiral or concentric track, and this track is divided into a plurality of groups in the radial direction, and the number of sectors per track increases or decreases in each group depending on the position in the radial direction. The first half has one or more special tracks that cannot be recorded at the boundary between the groups, and has index information at the beginning of each sector of the special track and an index at the beginning of each sector of the recordable track. In a recording/playback device that uses a disc that is preformatted with flag information that can be distinguished from the special track information and also shows the order of one or more special tracks, when searching for a target track, the current track address and the purpose A recording/reproducing apparatus characterized in that the search is performed based on the number of tracks obtained by adding the number of special tracks between the current track and the target track to the difference between the track address and the target track. (2) When the current track is a special track, when searching for the target track, the number of special tracks between the current special track and the target track is calculated from the flag information. The recording and reproducing apparatus according to claim 1, characterized in that: