Pioneer Corporation

Pioneer Digital Design and Manufacturing Corporation

Yasushi Oshima

Yoshio Sasaki

Kenichi Oono

An information recording/reproducing method includes: setting light beam power from a light source, to second power P, which is weaker than first power P, and detecting the number of the recording layers provided for an optical disc; controlling an objective lens to focus the light beam on one recording layer which is the closest to the objective lens, in a condition that the detected number of the recording layers &#x2267;3; setting the power of the light beam to third power Pbetween Pand P; specifying the number of the recording layers provided for the optical disc on the basis of layer information, which is information associated with the one recording layer; and setting the power of the light beam to Preading the layer type information recorded in advance in the one recording layer, and specifying a disc type based on the read layer type information.

Information recording / reproducing method and apparatus, and information reproducing apparatus

An optical axis shift correcting device is provided in an optical information device including an irradiation element for applying a laser, an optical system for guiding a laser applied to an optical disc having a recording track, and a light reception element for receiving the light from the optical disc generated by the guided laser via the optical system. The optical axis shift correcting device includes a jitter acquisition element, an optical axis modification element modifying the direction of the optical axis with respect to the light reception element, and a control element controlling the optical axis modification element to reduce the shift when the acquired jitter amount exceeds a predetermined threshold value. The optical axis shift correcting device thus corrects the optical axis light shift on the surface of the light reception element with respect to the radial direction of the optical disc set in the optical information device.

Growing community of inventors

Adachi, Japan

Yasushi Oshima