Compact disc medium, information recording method and compact disc driver

A technology for information recording and optical discs, applied in the direction of optical recording heads, optical recording carriers, disc-shaped recording carriers, etc., can solve the problems of high track thermal interference, difficulty in handling multiple tracks, and no commercially available optical disc equipment with multiple spots. , to achieve high transmission rate, simplify configuration, and realize the effect of transmission rate

Inactive Publication Date: 2009-04-29
HITACHI LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is very difficult to handle multiple tracks with these devices
Furthermore, in the case of recording type optical discs, when a plurality of adjacent tracks are simultaneously recorded, the risk of thermal interference between tracks is very high
[0012] Due to the above problems, there are few commercially available optical disc devices using multiple spots, although various proposals have been published up to now.

Method used

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  • Compact disc medium, information recording method and compact disc driver
  • Compact disc medium, information recording method and compact disc driver
  • Compact disc medium, information recording method and compact disc driver

Examples

Experimental program
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Effect test

no. 1 example

[0033] In the case of a recording type drive, it is necessary to prepare the same number of light sources (lasers) as the number of spots. Various methods are conceivable for mounting multiple lasers on a pick-up device. However, two or four lasers are considered practical in consideration of adjustability, size of signal processing circuits, operating frequency, etc. Thus, a case where the number of parallelism is set to four will be described below.

[0034] The disk format based on the present invention has the following characteristics:

[0035] (1) The format is formed as a single spiral;

[0036] (2) A block includes four sub-blocks;

[0037] (3) The format includes an area defined by an address range and a radius; the number of subblocks contained in a circle within the same area is constant; and

[0038] (4) The sub-blocks belonging to a certain block are arranged in the radial direction of the disc, and the distance (the number of tracks) between the sub-blocks is...

no. 2 example

[0049] When all sub-blocks belonging to a certain block are arranged in phase in the radial direction as described in the first embodiment, the block length in the circumferential direction is effectively shortened. Thus, the influence of disc defects tends to become larger. will use Figure 5A and 5B illustrate this aspect. like Figure 5A As shown, assuming that there is a block 7 that is not divided into sub-blocks, and that there is a defect 8 with a diameter d in it, the length of the defect observed at the time of reproduction is naturally equal to d. Here, the magnitude of d is estimated to be several millimeters.

[0050] Meanwhile, FIG. 5B illustrates a case where all sub-blocks belonging to a certain block are radially arranged in a single phase similarly to the first embodiment, in which there is a similar defect having a diameter d. For drawing purposes, Figure 5B has been elongated in the radial direction (vertical direction in the figure). Since the sub-bloc...

no. 3 example

[0053] In the case of reproducing several consecutive blocks, even when Image 6 As shown, when the sub-blocks are arranged offset in the circumferential direction, there is little difference in the average transmission rate compared to the case of a radially aligned sub-block layout. On the other hand, in the case of, for example, randomly reproducing short data, the time required for outputting the data in the first block after starting the reproduction is four times longer than in the case of arranging the sub-blocks in the radial direction. As a result, the advantage of parallel reproduction is destroyed.

[0054] In the case of discs based on the invention, the user can choose whether to apply Image 6 layout shown. Specifically, the sub-block layout mode can be selected when formatting the disc. This information is recorded in the control data area 9 located in area 0 (the innermost area). Based on this information, a drive configured to record and reproduce data on ...

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Abstract

Provided are an optical disk drive and a disk format necessary for the optical disk, which are capable of eliminating or reducing a problem of reduction in an effective transfer rate attributable to track jumps caused at a certain interval when performing recording and reproduction of multiple tracks in parallel by using multiple beams, and thereby achieving a high transfer rate. A block constituting a recording unit is divided into sub-blocks, and the sub-blocks are arranged in a radial direction of a disk. Meanwhile, an optical disk drive includes a means for irradiating a disk with multiple light spots, a means for pulse modulating the spots by using the same frequency and different phases, and a means for receiving light from the spots reflected by the disk by using a single photodetector, and separating the reflected light into independent lines of signals in terms of a time domain.

Description

[0001] priority claim [0002] This application claims priority from Japanese application JP2007-273582 filed on October 22, 2007, the contents of which are hereby incorporated by reference into this application. technical field [0003] This application relates to optical disc formats and optical disc drives. Background technique [0004] One of the main performances of an optical disc drive is the data transfer rate at the time of recording and reproduction (hereinafter simply referred to as "transfer rate"). The transfer rate is mainly determined by the linear recording density and the linear velocity of the disc. At the same time, the disc linear velocity is limited by the available rotational speed of the disc. In the case of a disc with a diameter of 12 cm and made of polycarbonate, a material used for almost all optical discs, the rotational speed limit is considered to be around 10000 rpm (revolutions per minute). This is due to the increased risk of disc damage w...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B7/007G11B7/12
CPCG11B2220/2537G11B7/00736G11B2020/1297G11B7/00745G11B2020/1232G11B20/1217G11B2020/1238
Inventor 菊川敦
Owner HITACHI LTD
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