Hitachi, Ltd.

Hitachi-lg Data Storage, Inc.

Other

Makoto Nihei

Toshimitsu Kaku

Akihiro Asada

Takashi Hoshino

Atsushi Saito

Junichi Ishii

Kenji Akahoshi

Laser light irradiation can be performed on a recordable surface in a defocused state with a high-power laser beam with safety without incurring data destruction due to erroneous data recording or overwrite recording even in the recording on an eccentric disk or regardless of occurrence of wobbling of the disk surface. Laser irradiation is performed after moving an objective lens radially inwardly beyond a PCA located at an inner peripheral portion of the disk (or radially outwardly beyond the PCA located at an outer peripheral portion of the disk) by using a tracking coil.

Apparatus and method for calibrating laser power in an optical disk apparatus

An optical disk apparatus uses a laser driver which can measure the frequency of the high-frequency superimposed current of the semiconductor laser simply and accurately. The apparatus includes a semiconductor laser which emits a laser beam onto the optical disk, a laser driver which drives the semiconductor laser with a current, with the high-frequency current being superimposed thereon, and measures the frequency of the high-frequency current, and a main controller which controls the frequency of the high-frequency current produced by the laser driver by using the frequency measured by the laser driver.

Laser driver, optical disk apparatus using the same, and laser control method

Growing community of inventors

Hitachinaka, Japan

Makoto Nihei