Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Reexamination Certificate
1998-06-16
2001-07-10
Huber, Paul W. (Department: 2651)
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
C369S044290, C369S275300, C369S275400
Reexamination Certificate
active
06259658
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a recording/reproducing optical disk, in which data recording/reproduction can be conducted by use of a sector disposed along a spiral track as a unit, and to an optical disk reproducing apparatus for data recording/reproducing on the optical disk.
Heretofore, rewritable optical disks available on the market have included optical disks having diameters of 120 mm and 90 mm and phase change disk of 120 mm in diameter (popular as PD).
These disks comprise guiding grooves for laser light illumination. Tracking is carried out by analyzing laser light based on the guiding grooves. The guiding grooves are formed as a continuous spiral which runs from the inner side of the disk to the outer side thereof. Heretofore, the guiding grooves each are referred to simply as “a groove” and a portion other than the grooves are referred to as “a land.” In a conventional optical disk, information has been recorded either in a groove or on a land.
Such information on an optical disk is read and written for example, in 512 bytes or 2048 bytes as a unit. This information unit is called “a sector.” In this sector, a sector address which indicates a location of the sector is assigned and formatting is conducted according a predetermined sector format in order to record information to a target address and to reproduce the information with high reliability. In the formatting, information on a sector is recorded by forming a recess/protrusion profile called “a pit” at a head of the sector. This portion in which the sector address information is recorded is called “a header.” In a conventional optical disk, as described above, since information has been recorded in either a groove or a land, the header must be either in a groove for groove recording, or on a land for land recording.
While a conventional optical disk has recorded information either in a groove or on a land as described above, the recording capacity of the disk can easily be increased if information is recorded on both the groove and the land.
However, a problem arises regarding formatting the sector address in a manner such that information can be recorded in both the land and the groove.
In a conventional optical disk provided with a spiral groove as described above, the groove and the land are formed parallel to each other, hereinafter referred to as a double spiral structure.
In a double spiral structure, since grooves and lands are formed in parallel to each other, travel from a groove to a land requires a track jump. Therefore, whenever recording/reproducing of information is switched from a groove to a land and vice versa, a track jump or a seek is necessary, thereby making continuous recording/reproducing of information difficult.
Additionally, the only way to manufacture a disk in the double spiral format, is to separately format a sector in a groove (hereinafter referred to as groove sector) and another sector on a land (hereinafter referred to as land sector). Thus, it becomes difficult to format a disk, for example by a zone CAV format, so that recording/producing of information can alternately be conducted on a land or in a groove adjacent to each other.
That is, in order for a land and a groove adjacent to each other, to have sector addresses numbered in a continuous manner, either the grooves or lands must be independently formatted, while being separately assigned with addresses in an intermittent manner. In this case, unless travel from a land to a groove or vice versa is smoothly performed, disk rotational delay time occurs, which causes a problem of interference with realization of continuous recording/reproducing of information.
In addition, its desirable to achieve as much distance between pits in a header as possible in order to perform a more stable reading of the header.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide an optical disk information medium with higher reliability in reading a header and detecting a switch-over position between a land and a groove in a stabilized manner. Such an optical disk can be provided by disposing header areas on the optical disk in a zig-zag shifted manner using an optical disk fabricating apparatus for the same medium.
The present invention is directed to a data recording/reproducing optical disk comprising: a first recording section RF
1
, RF
3
, RF
2
, RF
4
, which is an area in the shape of a land formed on a spiral track, and in which data recording/reproducing is conducted; a second recording section RF
5
, RF
7
, RF
6
, RF
8
adjacent to the first recording section, which is an area in the shape of a groove formed on the spiral track, and in which data recording/reproducing is conducted. Also provided is a first half header section HF
1
, HF
3
, in which first address information corresponding to the first recording section is recorded; and a second half header section HF
2
, HF
4
, in which second address information corresponding to the second recording section is recorded, and which is disposed in a zig-zag shifted manner in pair with the first half header section. The first half header section, e.g. HF
1
, and the second half header section, e.g. HF
4
, are located ahead of the first recording sections e.g. RF
2
. Additionally, both half header sections are located to assume a first positional relation relatively to the first recording section and when the first half header section, e.g. HF
1
, and the second half header section, e.g. HF
2
, are located ahead of the second recording section e.g. RF
5
, both half header sections are located to assume a second positional relation other than the first positional relation relative to the second recording section.
The present invention has a configuration in which the first half header section HF
1
, HF
3
and the second half headers HF
2
, HF
4
are disposed in a zig-zag shifted manner with a space therebetween as shown in FIG.
1
A and therefore 1) reliability in reading is increased because a margin in distance between adjacent pits is provided, 2) a narrow beam exclusively used for a header is not necessary any longer and thus cutting can be possible by one beam with a high speed and 3) a switch-over position between a land and a groove can be detected with ease.
That is, according to a structure A as shown in
FIG. 7
, since there is no blank in a header section
103
lying between recording sections
101
and
105
, a distance between pits is smaller and thereby creates the possibility of an error reading the error in data.
On the other hand, according to a structure C of the present invention, since a blank is provided, a sufficient margin is available in distance between pits, hereby reliability in address reading can be improved.
For this reason, since a cutting process also has a sufficient margin in distance between pits according to an embodiment of the present invention, one beam can commonly be used for cutting of recording and address sections and both cuttings are thereby conducted in one operation. Therefore, there is no requirement for having a beam uses exclusively for cutting a header, as is in the case of the structure A. Thus, a speedy cutting process can be realized.
In an optical disk having such a double spiral structure as used in the present invention, there is a necessity for detection of switch-over in tracking polarity between land and groove areas. A positional relation of the headers located in the zig-zag shifted manner, that is, wobbling of each header, can be used for detection of switch-over timing. That is, a photodetector cell, which analyzes a reflecting light from a disk, outputs a first signal A corresponding to the outer side of a recording track and a second signal B corresponding to the inner side thereof, and in addition detects the difference between the signals as (A−B). The signal difference (A−B) assumes (A−B)>0 for a header which wobbles to the outer side, that is a positive sign [+] and on the other hand the difference assumes (A−B)<0 f
Osawa Hideaki
Tanoue Koki
Huber Paul W.
Kabushiki Kaisha Toshiba
Pillsbury & Winthrop LLP
LandOfFree
Recording/reproducing optical disk with zig-zag shift... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Recording/reproducing optical disk with zig-zag shift..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Recording/reproducing optical disk with zig-zag shift... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2540381