Abstract: A method of controlling a revolution speed of a spindle motor in an optical disk drive. Target RPMs and actual PWM signal values for maintaining the target RPMs are calculated according to recording linear velocities of an optical disk, and stored in a memory. The spindle motor is controlled by a PWM signal value greater than an actual PWM signal value for maintaining a desired target RPM, until an RPM of the spindle motor reaches the target RPM. Further, the spindle motor is controlled by the actual PWM signal value for maintaining the target RPM, when the RPM of the spindle motor reaches the target RPM.

Abstract: An apparatus or method for estimating a radial speed of a disc is suitable for an optical storage device. The apparatus is used in an optical storage device for receiving a pulse signal and an eccentricity, and generating an estimated radial speed of the disc. The apparatus comprises a frequency detector and a sinusoidal wave generator. The frequency detector is used for receiving the pulse signal and then outputs a rotation frequency. The sinusoidal wave generator is used for receiving the rotation frequency and the eccentricity, and then outputs an estimated radial speed value of the disc.

Abstract: A system for the on-the-fly control of jitter during optical disc mastering/recording includes a record disc (24) having a recording surface (26) thereon of the type in which a pit can be read directly after it is written. A write-laser (32) directs its write-beam (34) though an acousto-optic modulator (36) onto the recording surface (26) of the rotating record disc (24). A digital processor (42) accepts digital input values and outputs a signal to the acousto-optic modulator (36) that effectively gates the write-beam (34) on and off. A read-laser (46) is positioned downtrack from the write-laser (32) and reads the pits (16) immediately or shortly after being written by the write-laser (32). The output of the read-laser (46) is fed into a jitter detector (48) that senses the start and stop positions of a sequence of pits (16) and effects an analysis to arrive at a jitter value.

Abstract: For providing a optical disk driving device that is capable of accurately performing recording and reproduction also of disks including warpage without the provision of a tilt mechanism, a clamper is comprised of a central clamper portion for pinching and holding a disk with a turntable, and an outer clamper portion for abutting against an outer periphery of the disk and pressurizing the same in case the disk includes any warpage to thereby correct the warpage, if present, through pressurizing; it is accordingly possible to restrict an angle formed between a light beam and an information surface of the disk to be within a specified value for accurately performing reproduction.

Abstract: A disk apparatus in which a control unit performs a seek control includes a disk motor which rotates a disk placed at a loaded position in the disk apparatus. A motor driver controls the disk motor such that the disk is rotated by the disk motor at a controlled speed. A read/write head reads information from or writes information to the disk when the disk is rotated by the disk motor at the controlled speed. A head shifting unit shifts the head in a radial direction of the disk to a target location thereof when a seek is performed. A current supply control unit controls current supplied to the disk motor during the seek. In the disk apparatus, the current supply control unit cuts off the current supply to the disk motor for a predetermined period after a start of the seek.

Abstract: An apparatus for recording and/or reproducing information on and/or from a magneto-optical disk including an optical head for projecting a laser beam onto a magneto-optical disk and receiving the laser beam reflected by the disk, an up-down block arranged movably between a lower position and an upper position, an up-down motor for moving said up-down block up and down, a turntable for supporting the disk and a spindle motor secured to said up-down block and having a driving shaft coupled with said turntable for rotating the turntable, a position detecting device for detecting a position of said up-down block to derive a position signal when the up-down block is driven into the upper position, a rotation detecting device for detecting a rotation of said optical information record disk to derive a rotation signal when the optical information record disk is rotated at a predetermined revolving speed, and a control device for initiating a focus control for moving said objective lens and turntable relative to each

Abstract: An apparatus for recording and/or reproducing information on and/or from a magneto-optical disk including an optical head for projecting a laser beam onto a magneto-optical disk and receiving the laser beam reflected by the disk, an up-down block arranged movably between a lower position and an upper position, an up-down motor for moving said up-down block up and down, a turntable for supporting the disk and a spindle motor secured to said up-down block and having a driving shaft coupled with said turntable for rotating the turntable, a position detecting device for detecting a position of said up-down block to derive a position signal when the up-down block is driven into the upper position, a rotation detecting device for detecting a rotation of said optical information record disk to derive a rotation signal when the optical information record disk is rotated at a predetermined revolving speed, and a control device for initiating a focus control for moving said objective lens and turntable relative to each

Abstract: An apparatus for recording and/or reproducing information on and/or from a magneto-optical disk including an optical head for projecting a laser beam onto a magneto-optical disk and receiving the laser beam reflected by the disk, an up-down block arranged movably between a lower position and an upper position, an up-down motor for moving said up-down block up and down, a turntable for supporting the disk and a spindle motor secured to said up-down block and having a driving shaft coupled with said turntable for rotating the turntable, a position detecting device for detecting a position of said up-down block to derive a position signal when the up-down block is driven into the upper position, a rotation detecting device for detecting a rotation of said optical information record disk to derive a rotation signal when the optical information record disk is rotated at a predetermined revolving speed, and a control device for initiating a focus control for moving said objective lens and turntable relative to each

Abstract: A disk recording or playback device comprises a pickup movable along the rear surface of a disk, a motor for moving the pickup, arithmetic means for calculating the position of the pickup on the disk, and timer means for measuring the time taken for the movement of the pickup. Predetermined for controlling the operation of the pickup are a specified distance L1 the pickup is to be moved, and a standard period of time T1 taken for the pickup to move the distance L1. The pickup is moved the specified distance L1 by energizing the motor, and the time taken for the movement and measured by the timer means is compared with the standard time T1. The voltage to be supplied to the motor is calculated from the result of comparison. When the measured time is approximate to the standard time T1, the value of the voltage for the motor is temporarily stored in a nonvolatile memory.