Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Shuichi Yoshida

Kiyoshi Masaki

Kazuhiro Mihara

Takanori Okada

Noritaka Akagi

Tsutomu Kai

Sachio Fukuyama

Noriaki Urayama

Masaaki Kikugawa

Masaharu Imura

Yoshiki Kuno

Teruyuki Naka

Kazuhiko Kouno

Masanori Harui

Yoshiho Gotoh

Tatsushi Bannai

Takashi Kishimoto

Toshikazu Koudo

Toshio Inaji

Noriaki Wakabayashi

Ryosuke Shimizu

Hiromi Onodera

Makoto Maruoka

Noriaki Kubo

Jyun-ichi Komeno

Shinichiro Obayashi

Hiroshi Mitani

Tsukasa Yoshiura

Nobukatsu Okuda

Shigeru Matsukawa

Mitsuo Tokura

Isao Takemoto

Yukihiro Dojo

Yasuo Kashiwagi

Noriaki Wakabashi

A standard reproduction model for ensuring real time reproducing on a disk-shaped information recording medium, includes a pickup () that reads the real time data from the information recording medium, a buffer memory () that temporarily stores the real time data read by the pickup, and a decoding module () that reads the real time data from the buffer memory () and processes the read real time data. An access time Tacc of the standard reproduction model is expressed by the following formula,where dN is a difference in rotational speed of the disk-shaped information recording medium, Trev is a rotation waiting time at a target access position, A and B are constants.

Reproducing method for reproducing real time data from a disk-shaped information recording medium

An encryptor is provided for encrypting AV data sent from an interface. A controller controls recording of the encrypted AV data by controlling a recorder for recording the encrypted AV data in a magnetic disk. The recorder is controlled by the controller so as to reproduce the data recorded on the disk. A decrypter decrypts the reproduced data that is sent to the interface.

Recording apparatus, reproduction apparatus, data processing apparatus, recording and reproduction apparatus and data transmission apparatus and corresponding methods

Method and apparatus for recording real-time data into an optical disc

A digital watermarking apparatus inputs video or audio information and embeds digital watermark in the information, which is capable of preventing digital watermark or set values necessary for digital watermarking operation from being altered. The apparatus includes a verifying section, a decrypting section and a watermarking section. The verifying section verifies encrypted set values using verification data in set values which is added with verification data and encrypted together with verification data, and transmits the verification result to the watermarking section. The verifying section also transmits the encrypted set values which are verified to the decrypting section. The decrypting section decrypts the encrypted set values. The watermarking section embeds digital watermark in the information using the decrypted and verified set values to output it, when a verification result from the verifying section is normal. When the verification result is not normal, the watermarking section does not output the input information to the outside of the apparatus.

Digital watermarking apparatus and application apparatus using the same

An information reproducing apparatus reproduces one type of information (for example, video information) in synchronous with a plurality of channels of other type of information (for example, audio information) with high copyright protection, and includes a decryption section that decrypts multiplexed stream reproduced from a recording medium, a stream analyzer that analyzes the multiplexed stream which is decrypted to detect first information (video information) contained in the multiplexed stream, a stream conversion section that alters the first information contained in the multiplexed stream which is decrypted, based on an analysis result by the analyzer. The multiplexed stream with altered video information is distributed to second to n-th stream decoders (for example, for achieving a multilingual system).

Information reproducing 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

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.

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Osaka, Japan

Shuichi Yoshida