Pioneer Electronic Corporation

Noriko Obitsu

Toshio Suzuki

Yuji Tawaragi

Satoshi Kusano

Shinichi Takahashi

An optical disk player having a tracking servo apparatus and a focusing servo apparatus. By amplifying a focusing error at a predetermined gain and adding it to a tracking error, the rolling which occurs due to a mass balance distortion of a pickup is electrically suppressed. Thus, an adverse influence on the tracking servo by the rolling upon focusing driving can be prevented.

Optical disk player having beam correction means

An optical disk player provided with tilt servo unit. A quadrant type photodetector is used as disk tilt detecting means, and the push-pull output is issued as a disk tilt detecting signal. By simultaneous use of the photodetector of the pickup, there is no need to use special-purpose tilt sensor, and this contributes to compact design of the pickup and to the reduction of manufacturing cost.

Optical disk player having tilt servo control absent tilt sensor

A tracking servo system of disk player uses the time difference detection method for generating the tracking error signal. A time gate is provided for detecting the zero-crossing of the tracking error level in an on-track condition during a jumping operation. As the result, negative effects due to unstableness in timing of the zero-crossing can be eliminated.

Tracking servo system

An optical disk player using quadrant type photodetector as light receiving means. The phase difference output by the time difference detection method is issued as a tracking error, and a DC component of differential output by the push-pull method is issued as a tilt error, and zero cross of said differential output is detected. By using this detection output for the detection of zero-cross timing on off-track, stable operation of the tracking servo unit is ensured.

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Tokorozawa, Japan

Noriko Obitsu