Dynamic information storage or retrieval – Information location or remote operator actuated control – Selective addressing of storage medium
Reexamination Certificate
1999-10-27
2002-04-30
Dinh, Tan (Department: 2651)
Dynamic information storage or retrieval
Information location or remote operator actuated control
Selective addressing of storage medium
Reexamination Certificate
active
06381201
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical disk apparatus for optically reproducing/recording a signal from/to an information carrier using an light beam from a light source such as a semiconductor laser. More particularly, the present invention relates to an optical disk apparatus for reproducing/recording a signal from/to a recordable disk having address sections which are wobbled about a track.
2. Description of the Related Art
An information carrier (optical disk) such as CD-AUDIO, CD-ROM, DVD-VIDEO and DVD-ROM contains information recorded thereon as concave/convex pits arranged along a single spiral track which spirally runs from the inner periphery of the disk to the outer periphery thereof.
In order to properly reproduce a signal on the track, a conventional optical disk apparatus typically performs the following control operations: a rotation control for rotating the optical disk at a predetermined number of revolutions: a focusing control such that the optical disk is irradiated with a light beam having a predetermined focused state; and a tracking control such that the light beam properly scans along the track of the optical disk.
Recent development in the high-density optical disk technology has seen the advent of a recordable optical disk “DVD-RAM” (digital versatile disk-random access memory).
Such a recordable DVD-RAM includes address sections as well as data sections where data can be recorded. Such a recordable optical disk is divided into a plurality of concentric zones which are successively arranged from the inner periphery of the optical disk to the outer periphery thereof. Each data section includes a guide groove (or a groove track) and a land track between two adjacent groove tracks.
FIG. 11
illustrates a portion of a recordable optical disk. Referring to
FIG. 11
, each data section includes a concave groove track
207
and a convex land track
206
. A single pair of the groove track
207
and the land track
206
runs in a spiral pattern across the optical disk. An address section
205
is provided to interrupt the extent of the pair of the groove track
207
and the land track
206
along a boundary between the tracks
206
and
207
. An actual beam spot on the optical disk is larger than the width of the track
206
or
207
. Therefore, as the light beam moves along the groove track
206
or the land track
207
, the beam can read an address in the address section
205
which is arranged along a boundary between the tracks
206
and
207
.
An address
210
, for example, is formed along a boundary between a track
209
and a track
202
. Similarly, addresses
201
and
204
are formed respectively along a boundary between tracks
202
and
203
and along a boundary between tracks
203
and
208
. Thus, a groove track and an adjacent land track share an address.
The track
202
is defined by the addresses
210
and
201
. Similarly, the track
203
is defined by the addresses
201
and
204
. These addresses are searched when recording data along a predetermined track or when reproducing the recorded data therefrom.
A spiral track formed by a string of pits (as in conventional CDs and DVD-ROMs) is not divided into zones. For such a spiral track, data is recorded from the inner periphery to the outer periphery at a constant linear velocity (i.e., at a constant recording density). In such a disk, as long as the CLV (constant linear velocity) control is properly performed, a PLL (phase locked loop) is pulled-in so that an address or data can successfully be reproduced.
In an optical disk such as a DVD-RAM, on the other hand, the data region is formed by land and groove tracks and is divided into zones, The zones have different numbers of revolutions and different PLL target clock frequencies, respectively. Thus, it is necessary to know which zone is being reproduced/recorded.
Typically, a stepping motor, an encoder, or the like, is used in an optical head traverse drive system of an optical disk recording apparatus. For example, an encoder can be used to implement a system capable of detecting the zone where the light beam is currently located. In such a case, a traverse control may be performed based on a pulse signal from the encoder, while using a pulse signal value for the innermost position of the disk as the initial value.
However, in view of improving the precision and reducing the cost, there is a demand in the art for the use of an inexpensive and simpler DC motor.
When reproducing a DVD-RAM disk with the above-described conventional optical disk apparatus, a single track (either a land or a groove) is identified by a pair of addresses along the opposite sides of the track. If, for example, there is a speck of dust in the address section of the address
210
or if a lens shift occurs to displace the light beam in the direction indicated by an arrow N in
FIG. 11
, the address
210
may not be properly read when the light beam is scanning along the track
202
. In such a case. It is not possible to determine whether the current track is the track
202
or the track
203
based only on the address
201
, whereby a data reproduction/recording operation cannot be performed properly.
Moreover, with the conventional optical disk apparatus, the position of the light beam cannot be known immediately after the initialization of the apparatus. The zone where the light beam is currently located is identified only after an address is successfully reproduced by successively switching among the numbers of revolutions and the PLL target frequencies for the respective zones. Thus, such a conventional apparatus has an undesirably long start-up time.
SUMMARY OF THE INVENTION
According to one aspect of this invention, an optical disk apparatus includes: a light amount detection section for irradiating an information carrier with a light beam so as to detect information recorded in a data section of the information carrier, wherein the information carrier includes the data section and an address section associated with the data section, the data section is an information track formed by a land or a groove where information can be recorded or reproduced, and the address section contains address information corresponding to the information track which is recorded in the address section by one or more concave or convex pit offset by a predetermined distance from a center of the information track; an address polarity determination section for determining whether the address section over which the light beam has passed is either on an outer periphery side or on an inner periphery side with respect to the center of the information track being scanned by the light beam, based on a signal output from the light amount detection section: an address reproduction section for reproducing the address information recorded in the address section based on a signal output from the light amount detection section: and an address confirmation section for confirming the data section from which or to which data is to be reproduced or recorded, based on the determination result from the address polarity determination section and the address information reproduced by the address reproduction section.
In one embodiment of the invention, the address section includes two or more address regions where the address information is recorded. The address regions are wobbled by a predetermined distance about the center of the information track. The address region is shared by a pair of adjacent information tracks.
According to another aspect of this invention, an optical disk apparatus includes: a light amount detection section for irradiating an information carrier with a light beam so as to detect information recorded in a data section of the information carrier, wherein the information carrier includes the data section and an address section associated with the data section, the data section is an information track formed by a land or a groove where information can be recorded or reproduced, and the address section contains address informat
Kimura Naohiro
Shihara Tetsuya
Takahashi Hidemi
Watanabe Katsuya
Dinh Tan
Matsushita Electric - Industrial Co., Ltd.
Renner Otto Boisselle & Sklar
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