Matsushita Electric Industrial Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Noritaka Akagi

Shuichi Yoshida

Kiyoshi Masaki

Tsutomu Kai

Takanori Okada

Kazuhiro Mihara

Masaharu Imura

Kazuhiko Kouno

Masanori Harui

Kazuo Momoo

Yuichi Takahashi

Yoshiki Kuno

Teruyuki Naka

Isao Takemoto

Yasuo Kashiwagi

A record playback apparatus of the present disclosure includes a plurality of optical pickups that records information on a recording medium or plays back information from the recording medium; a single transport mechanism that transports the plurality of optical pickups together; and a transport control circuit that drives the single transport mechanism so that, when the single transport mechanism is driven to transport the plurality of optical pickups to respective target positions on the recording medium, absolute value of a maximum value of transport errors of the plurality of optical pickups with respect to the respective target positions becomes substantially equal to absolute value of a minimum value of transport errors of the plurality of optical pickups with respect to the respective target positions.

Record playback apparatus

A disk drive apparatus for a disk having helically-formed or concentric circle-like formed tracks includes a spindle motor for controlling a rotation of the disk; a pick-up device for recording or reproducing information on or from the disk; a stepping motor for moving the pick-up device in a radial direction of the disk in accordance with a drive current; a system controller for tracking a rotation speed of the spindle motor and for outputting command signals according to the rotation speed of the spindle motor; and a stepping motor controller for controlling the stepping motor by changing a slope of a rising part and a falling part of a waveform of the drive current of the stepping motor according to the command signals.

Disk drive apparatus

A disk apparatus includes a pick-up for reading/writing signals from/on a disk; a pick-up base provided with the pick-up; a traverse motor for moving the pick-up in a radial direction of said disk; a feed screw rotated by the traverse motor and provided with a thread groove on its periphery; a rack having a fixing portion fixed to the pick-up base and a nut portion engaged with the thread groove; a guiding mechanism for guiding the pick-up movably in a radial direction of the disk; and a cantilever parallel spring for connecting the fixing portion to the nut portion of the rack, displaceably in a radial direction of the feed screw.

Stepping motor controlling method and disk apparatus

In a method of the present invention for controlling stepping motor, the stepping motor driving current is increased or reduced at a fixed inclination in proportion to the time to control the stepping motor effectively, and, a stepping motor driving current pattern is changed by &frac14; cycle or more to synchronize the state of excitation between the stepping motor driving means and the stepping motor to control the pick-up very accurately. In addition, the disk apparatus of the present invention, which uses a stepping motor is provided with a pulse rate pattern variable means, a pulse rate change proportion measuring means, and a driving voltage variable means, and when the pulse rate and the pulse rate change proportion are low, the driving voltage amplitude is lowered to reduce surplus torque generation in the stepping motor.

Stepping motor control method and disk drive apparatus

In order to correct the change in the offset and amplitude of a tracking error signal because of the change in the position of an object lens from the center of an optical pickup, the offset amount and amplitude value of the tracking error signal with respect to the displacement amount of the object lens from the center of the optical pickup are checked beforehand, and the displacement amount of the object lens is estimated on the basis of a tracking correction signal by using an object lens displacement observer. An offset detection section and an amplitude detection section detect the offset amount and amplitude value of the tracking error signal respectively, and the tracking error signal is corrected by an offset correction circuit and an amplitude correction circuit on the basis of the offset amount and amplitude value having been checked beforehand so that the offset amount and the amplitude value of the tracking error signal become identical to those obtained when the displacement amount of the object lens is zero. In addition, the offset of the tilt error signal depending on the movement direction of the optical pickup is detected and recorded beforehand, and the tilt error signal is corrected on the basis of the above-mentioned recorded offset when a rotation direction detection section detects the moving direction of the optical pickup.

Optical information recording/reproducing device

In a method of the present invention for controlling stepping motor, the stepping motor driving current is increased or reduced at a fixed inclination in proportion to the time to control the stepping motor effectively, and, a stepping motor driving current pattern is changed by 1/4 cycle or over to synchronize the state of excitation between the stepping motor driving means and the stepping motor to control the pick-up very accurately. In addition, the disk apparatus of the present invention, which uses a stepping motor is provided with a pulse rate pattern variable means, a pulse rate change proportion measuring means, and a driving voltage variable means, and when the pulse rate and the pulse rate change proportion are low, the driving voltage amplitude is lowered to reduce surplus torque generation in the stepping motor.

The present invention provides the following rotation control method for reducing energy consumption of a motor driving a disk. In a constant speed mode, a supply voltage V1 for driving the motor at a constant speed N1 is selected; however, at a lower constant speed N2, a supply voltage V2 lower than V1 is selected. In an acceleration mode for accelerating the motor speed from N2 to N1, a higher supply voltage than V1 is selected just before starting acceleration, and then V1 is selected after the acceleration. In a speed deceleration mode for decelerating the motor speed from N1 to N2, a lower supply voltage than V1 is selected just before starting deceleration, then the supply voltage V2 is selected after the decleration.

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Osaka, Japan

Noritaka Akagi