Hitachi, Ltd.

Other

Hitachi Software Engineering Company, Ltd.

Hitachi Video and Information Systems, Inc.

Hiroyuki Minamura

Hisataka Sugiyama

Tetsuya Fushimi

Shigeki Yamazaki

Makoto Itagaki

Yoshio Suzuki

Toru Kawashima

Hisamitsu Tanaka

An optical disc apparatus and method for recording and reproducing information to/from an optical disc, including discrimination of the optical disc, reading control information in an un-recordable area formed in an inner periphery of the optical disc, conducting focus control based on a focus error signal in a recordable area formed outside of the un-recordable area, and determining an optimum offset value of the focus error signal in the recordable area. Further, adjustment in amplitude of a reproduced signal from an inner periphery of the recordable area is conducted, test-writing in the inner periphery of the recordable area is conducted, test-writing in an outer periphery of the recordable area is conducted, and adjustment in amplitude of a reproduced signal from the outer periphery of the recordable area is conducted. The respective operations are conducted sequentially so as to make the optical disc in a reproducible and recordable condition.

Optical disc apparatus and method thereof

An optical disc apparatus having at least two optical condenser lens for recording and reproducing information of an optical disc, comprising: means for discriminating the optical disc; means for reading control information in a ROM area which is formed in an inner periphery of said optical disc; means for conducting focus control in a RAM area which is formed outside of said ROM area; means for conducting adjustment in amplitude of a reproduced signal from an inner periphery of said RAM area; means for conducting a pre-writing (a sample-writing); means for conducting test-writing in the inner periphery of said RAM area; means for conducting test-writing in an outer periphery of said RAM area; and means for conducting adjustment in amplitude of a reproduced signal from the outer periphery of said RAM area, wherein said means conducts the respective operations sequentially, thereby making said optical disc in reproducible and recorable condition, with a short time period and with a smooth confirmation operation.

For a disk of a land/groove scheme with land tracks and grooves appearing alternately, in order to enable stable and reliable reproduction of information as recorded on a disk by stably and reliably detecting a specific position at which a land track and groove change therebetween, a technique is employed for detecting the position whereat one land track is changed to a groove, or vice versa, by utilizing an HPP signal rather than an RF signal in cases where an optical head 103 attempts to reproduce certain information at the pit formation position of a disk 101. In addition, detect the polarity--positive or negative--of a pit signal appearing in the HPP signal, and then detect the position whereat the land track and groove change therebetween based on the position at which the order or sequence thereof changes, thereby permitting effectuation of optical head's tracking control and focus control by a method suitable for its respective parts.

Method and apparatus for detecting position of alternated land and

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Kokubunji, Japan

Hiroyuki Minamura