Pioneer Corporation

Yuko Muramatsu

Masahiro Kato

Shinji Suzuki

Naoharu Yanagawa

Tatsuhiro Yone

In an error counting apparatus and method, there are provided a reproducing section for reproducing the optical disc and a counter for counting the error number of the pre-pit signal based on an output of the reproducing section. When it is detected that the reproducing section come up to the reproduction of the emboss portion, a counting operation of the counter is started in response to this detection. When it is detected that the reproducing section has reproduced the optical disc in the predetermined interval after the counting operation is started, the counting operation of the counter is stopped in response to this detection.

Error counting apparatus for counting an error number of a pre-pit signal in an optical disc and method therefor

An AR measuring apparatus receives the reflection light of an optical beam irradiated on an optical recording medium having a recording surface on which pre-pits are repeatedly formed between tracks by means of a first light receiving surface and a second light receiving surface, obtains a push-pull signal based on the difference between light receiving signals from the first and second light receiving surfaces, collects sample data by sampling the push-pull signals for a predetermined period of time, repeats the sampling for the predetermined period of time by a plurality of times, determines whether or not each data value corresponding to a pre-pit position of the sample data by the plurality of times is obtained by a predetermined number of times or greater, and when data values obtained by the predetermined number of times or greater are determined, calculates as an aperture ratio, a ratio between the minimum value and the maximum value of values corresponding to a pre-pit component of the data values obtained by the predetermined number of times or greater.

Aperture ratio measuring apparatus for optical recording medium with pre-pits

A plurality of light receiving detectors receive a plurality of segments of a beam returning from an optical disc when a reading beam of light is radiated to the optical disc. An optical pickup assembly produces a plurality of signals from the beam segments in accordance with, for instance, optical intensities of the beam segments. A level adjusting circuit adjusts signal levels of these signals such that each of the signal levels of the signals becomes equal to a reference level. The reference level is determined from at least one of the signal levels of the received beam segments.

APPARATUS FOR ADJUSTING SIGNAL LEVELS DERIVED FROM AN OPTICAL DISC TO BECOME EQUAL TO A REFERENCE LEVEL DETERMINED FROM AT LEAST ONE OF THE SIGNAL LEVELS OF THE SIGNALS AND FOR SYNTHESIZING THE SIGNALS

A pre-pit detecting apparatus which, when a light beam is radiated onto an optical recording medium having a recording surface with pre-pits repeatedly formed between tracks, receives light reflected by the recording surface with first and second light receiving faces, obtains the push-pull signal corresponding to the light receiving signals for the first and second light receiving faces, and binarizes the push-pull signal by using a threshold value to generate a pre-pit detection signal. It is judged which area of a plurality of areas including at least a not-yet-recorded area corresponds to a position of the recording surface where the light beam is radiated is performed to judge. Then the threshold value is set in accordance with the judgement result.

Pre-pit detecting apparatus for optical recording medium

An optically recorded information recording and/or reading apparatus which eliminates the influence of stray light occurring within an optical system. In a state or a focus state which is forcedly set to position a reading point outside the outermost periphery of a disk surface, and the signal level is adjusted in a signal combiner circuit such that a light receiving level at that time matches a desired level.

Optical device including a calibrating unit for calibrating a level adjusting unit

A pre-pit detecting apparatus which, when a light beam is radiated onto an optical recording medium having a recording surface with pre-pits repeatedly formed between tracks, receives light reflected by the recording surface with first and second light receiving faces, obtains the push-pull signal corresponding to the light receiving signals for the first and second light receiving faces, samples the push-pull signal to collect sample data for a predetermined period, and sets a threshold value between the maximum value of data corresponding to a track and the minimum value of data corresponding to a pre-pit, of the collected sample data.

Growing community of inventors

Tokorozawa, Japan

Yuko Muramatsu