Matsushita Electric Industrial Co., Ltd.

Junji Nagaoka

Seiji Nishiwaki

Kazuo Momoo

Kenji Nagashima

Junichi Asada

Yuichi Takahashi

Youichi Saitoh

An optical disk device has a light source which emits light; and light converging means of, in each of signal mark forming regions, each of lands, or each of grooves of an optical disk, converging the light from the light source onto a signal surface of the optical disk with selectively positioning a signal mark at any one of plural positions which are arranged in a direction that is substantially perpendicular to tracks, each of the signal mark forming regions surrounded by adjacent two of boarder lines which are between two the tracks on the signal surface of the optical disk, and which are substantially parallel to the tracks, and each of which substantially divides an area between adjacent tracks in two parts.

Optical disk with plural signal mark positions in a direction substantially perpendicular to tracks

An optical disk apparatus has an optical head having a lens of converging light from a light source onto an optical disk and a photodetector for detecting the light thus converged and then reflected from the optical disk. A tracking error signal is generated in order to perform tracking control on the basis of the detected light. A disk tilt DT is detected to indicate the amount of tilt of the optical head relative to the optical disk. A calculation is performed to calculate a lens shift LS indicating the amount of shift of the lens relative to the optical head, according to a predetermined rule on the basis of the generated tracking error signal and the detected disk tilt DT.

Optical disk apparatus, method for calculation of amount of lens shift, program and medium

An optical disk device has an aperture of an objective lens in an incoming path of a beam from a semiconductor laser to an optical disk formed larger than an aperture in a return path from the optical disk or an aperture is varied in recording and in reproduction. This configuration improves recording/reproducing ability since light is focused on an optical disk with high numerical aperture. In addition, since reflected light from the optical disk is detected with low numerical aperture, margins for tilt and defocus are not reduced. Furthermore, since unnecessary signal components contained in the reflected light can be eliminated, a S/N (signal-to-noise ratio) of an information signal also increases. Thus, a high-performance optical disk device can be obtained. Alternatively, by varying the aperture of an objective lens in recording and in reproduction, an optical disk device in which recording density and recording quality are increased without deteriorating reproduction quality can be obtained.

Optical information processor and optical element

Optical disk device having light converging means which marks plural signal mark positions in a direction substantially perpendicular to tracks

This optical disk device includes an objective lens ( ) for condensing radiated light from a light source on an optical disk ( ), an optical detecting unit for detecting reflected light from the optical disk ( ), and a control unit for performing the tracking control and/or the tilt control of the objective lens ( ) by utilizing the output from the optical detecting unit, in which the control unit uses the off-track quantity and/or the tilt quantity of the objective lens ( ) when performing the above described control.

Growing community of inventors

Takatsuki, Japan

Junji Nagaoka