Pioneer Corporation

Shin Akabane

Junji Tanaka

Naoharu Yanagawa

Takakazu Sugiyama

An information recording/reproducing apparatus irradiates a light beam on an optical disc on which pre-pits are formed, and performs recording and/or reproduction of information with respect to the optical disc according to a recording clock produced based on a wobble signal and a pre-pit signal. When recording information onto the optical disc having the pre-pits, a light beam is radiated to thereby extract the wobble signal and pre-pit signal. Then, according to the wobble signal and the pre-pit signal, a recording clock signal is produced, and information is recorded based on the recording clock signal. When producing a pre-pit signal, a push-pull signal is produced from the reflected light from the optical disc, and this signal is compared with a reference level to thereby detect a pre-pit. Here, when a pre-pit is not detected, the reference level is changed and the detection processing of the pre-pits is executed again.

Apparatus and method for re-executing pre-pit detection if pre-pits are not detected after changing reference level

A composite signal in which pre-pit signal components are piggypacked onto frequency components of wobbling, is extracted from an optical recording medium. The composite signal is binarized, so that pre-pit signals are generated. The pre-pit signals pass through a first gate when the gate is open. The gate is periodically opened only in a period during which the amplitude of the wobbling becomes a maximum one. The number of the pre-pit signals passing through the gate is counted, so that a binarizing level for generating the pre-pit signal is set based on the relationship between the counted number per a reference time and a predetermined reference number.

Pre-pit detecting device and binarizing level setting method

An optical recording apparatus includes a light source driving unit for driving the light source to emit the light beam; an emission light power detecting unit for detecting an emission light power from the light source; and a light power adjusting unit for controlling the light source driving unit based on a detected light power by the emission light power detecting unit to adjust the emission light power from the light source.

Growing community of inventors

Tokorozawa, Japan

Shin Akabane