Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Kiyoshi Masaki

Shuichi Yoshida

Kazuhiro Mihara

Tsutomu Kai

Noritaka Akagi

Sachio Fukuyama

Noriaki Urayama

Masaaki Kikugawa

Takanori Okada

Masaharu Imura

Kazuhiko Miyazaki

Teruyuki Naka

Kazuhiko Kouno

Masanori Harui

Shinichi Yamada

Masaya Kuwahara

Hideki Shirane

Makoto Maruoka

Shinichiro Obayashi

Tsukasa Yoshiura

Tatsuhiko Inagaki

Yuji Yagi

Toru Arakawa

Michiro Tanaka

Satoshi Suyama

Isao Takemoto

Masato Asano

Yasuo Kashiwagi

Yoshiyuki Sugahara

Souji Oba

An optimum method for adjusting the physical position or angle of an optical pickup (a) is automatically selected for each optical disc signal processing device so that a control target value after adjusted is included in a previous margin measurement result which is stored in a nonvolatile memory, thereby providing an optical disc signal processing device, an optical disc signal processing method, an optical disc reproduction and recording device, and an optical disc reproduction and recording method, which can reduce the start-up time and the recording start time, and enhance the user's convenience.

Optical disc signal processing device, optical disc signal processing method, optical disc reproduction and recording device, and optical disc reproduction and recording method

In a track jumping scan control device wherein an optical beam is irradiated on an optical disc provided with a header region capable of a mark-recording operation with respect to both of land and groove tracks adjacent in a radial direction of the disc and comprising prepits, and a signal based on a reflected light resulting therefrom is used to make the optical beam jumping-scan with respect to a predetermined track, a full track jumping scan for making the optical beam track-jump between the land tracks or the groove tracks or a half track jumping scan for making the optical beam track-jump from the land track to the groove track or from the groove track to the land track is executed as the track jumping scan. Which of the two track jumping scans is executed is selected in accordance with a cycle at which the header region is set.

Track jumping scan control device and track searching device

A second tracking error detector detects the displacement between the track and the light beam and outputs a second displacement detection result based on the comparison of the reproduction signals between first and second pit strings respectively. A second tracking error controller corrects a target position for push-pull control based on the second displacement detection result. A third tracking error controller calculates a correction data of a first displacement detection result based on the correction amount of the target position by the second tracking error controller, and corrects the first displacement detection result based on the calculated correction data.

Tracking error control apparatus, tracking error control circuit, optical disk apparatus and tracking error control method

An optical disc apparatus has: an optical headfor emitting a light beam onto a predetermined track of an optical discbefore tracking control in order to detect reflected light with a photodetector; an arithmetic circuitfor generating measurement signals each indicative of a time-varying change of light received on a respective one of a plurality of light receiving areas of the photodetector; an A/D converter circuitfor A/D converting each measurement signal; a microcomputerfor determining a correction value based on a difference, in terms of high- and low-frequency components, between measurement signals having been A/D converted; and an adder circuitfor adding the correction value to a driving value output from a tracking control circuit, so that the driving value is corrected.

Optical disc apparatus, tracking control method, and integrated circuit

A disk access device records to and plays back from a disk on which data recording is performed according to the ZCLV format, and includes a head that reads/writes data from/to the disk. The disk access device calculates a deferment time period that begins upon completion of data reading/writing in the user area of a currently accessed zone and ends when the head enters a predetermined area of the guard track zone following the user area, and a setting time period for performing settings for data reading/writing in the zone to be accessed next. If the deferment time period is shorter than the setting time period, the disk access device moves the head back, when data reading or writing in the currently accessed zone ends, to a position such that the setting time period ends before the head advancing from the position arrives at the predetermined area.

Disk access device

A tracking controller includes a tracking error detecting section and a tracking control section. The tracking error detecting section generates and outputs a tracking error signal that represents how much the focal point of a light beam has shifted from a target track on a storage medium. The tracking control section generates a drive signal in response to the tracking error signal so as to move the light beam such that the focal point of the light beam is located right on the target track. The gain of at least one of the tracking error signal and the drive signal is switched depending on whether or not the focal point of the light beam is located on a recorded area of the storage medium on which data has already been written.

Apparatus and method for tracking control

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

A disk drive includes a turntable and a clamper. The turntable and/or the clamper have four or more projections, each of which has predetermined height. The projections are arranged at positions for supporting/holding a mounted disk by using the four or more projections, wherein the projections are located at substantially equal intervals around a circumference of the turntable/clamper and the tips of the projections are substantially in the same plane.

Disk drive apparatus having particular clamping device

The present invention is intended to provide a disk drive apparatus capable of suppressing the occurrence of undesirable vibration due to the imbalance of a disk and capable of carrying out high-rate transfer, wherein a balancer is formed so as to accommodate a predetermined number of spherical bodies in a ring-shaped track portion having a predetermined shape, and this balancer is provided so as to be rotatable integrally and coaxially with the disk. In addition, in the disk drive apparatus of the present invention, the ring-shaped track of the balancer is divided into plural tracks by partition walls or the like, and a ball used as a balance member is disposed so as to be movable on each divided track. Furthermore, the disk drive apparatus of the present invention is configured so that the disk is held on both sides or one side thereof by using four or more projections or rubber sheets.

To provide a disk drive apparatus that suppresses undesirable vibrations due to the unbalance of a loaded disk and achieves high-speed data transfer, the disk drive apparatus of the present invention comprises a hollow ring member ( ) that contains therein a plurality of spherical bodies ( ) or a liquid ( ) to form a balancer, wherein the balancer is formed so as to be rotatable in integral fashion with a disk, thereby suppressing the vibrations generated when an unbalanced disk is rotated at high speed.

Balanced disk drive apparatus

To provide a disk drive apparatus that suppresses undesirable vibrations due to the unbalance of a loaded disk and achieves high-speed data transfer, the disk drive apparatus of the present invention comprises a hollow ring member ( ) that contains therein a plurality of spherical bodies ( ) or a liquid ( ) to form a balancer or a balancer, wherein the balancer is formed so as to be rotatable in integral fashion with a disk, thereby suppressing the vibrations generated when an unbalanced disk is rotated at high speed.

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

A balanced disk drive apparatus for suppressing undesirable vibrations caused by the unbalance of a detachable disk during high speed data transfer comprises a balanced disk drive apparatus having a hollow ring member containing a balancing member therein to form a balancer wherein the balancer is rotatable with the detachable disk for suppressing vibrations created by the unbalanced detachable disk during high speed rotation.

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.

Growing community of inventors

Amagasaki, Japan

Kiyoshi Masaki