Pioneer Electronic Corporation

Pioneer Corporation

Hiroyuki Fueki

Keiichi Takagi

Wataru Hasegawa

Toshiyuki Kaneko

Seiichi Yamazaki

The motor apparatus includes a motor and an insulating device. The motor such as a spindle motor is driven with pulse width modulation. Then, the insulating device insulates an object to be protected, which should be protected from a noise current generated from the motor, from the motor.

Current noise insulated spindle motor

A reading device is provided for reading information recorded on an optical disc. A relative displacement between the reading device and the optical disc is detected. The relative displacement is caused by rotating the disc at a speed higher than an ordinary speed. A maximum rotating speed of the optical disc at the time when the displacement reaches a predetermined value is detected. The optical disc is rotated at an angular velocity which does not exceed the maximum rotating speed.

Control system for controlling the rotational speed of a disc to a maximum speed without causing excessive vibration

A servo control device for controlling operation of tracking servo loop includes: on-track signal generating unit for generating on-track signal indicating whether a light beam irradiated on an optical disk is positioned on track of the optical disk or not, on the basis of the light beam reflected by the optical disk; tracking error signal generating unit for generating tracking error signal on the basis of the light beam reflected by the optical disk; discriminating unit for discriminating whether the light beam irradiated on the optical disk is positioned in pre-pit area or not; holding unit for holding value of the on-track signal immediately before entrance of the light beam to the pre-pit area on the basis of discrimination result of the discriminating unit; and control unit for opening and closing the tracking servo loop in accordance with the value of the on-track signal held by the holding unit and the tracking error signal.

Growing community of inventors

Saitama-ken, Japan

Hiroyuki Fueki