摘要:
An optical disc drive includes: a motor for rotating an optical disc thereon; a photoelectric transducer for converting a light beam, reflected from or transmitted through the disc, into an electric signal; a clock sync signal reader for extracting and outputting a read signal, representing a clock synchronization mark, from the electric signal; a clock generator for generating a clock signal having a variable frequency; a phase locking controller for controlling the clock generator to synchronize the clock signal in phase with the output signal of the clock sync signal reader; and a mechanism for displacing a light beam spot toward a target track on the disc. During a seek operation of displacing the light beam spot toward the target track, the clock generator is controlled to obtain a frequency to be expected on the target track and output a clock signal having the expected frequency.
摘要:
An optical disc drive includes: an optical head with an actuator and a photodetector; a tracking driver outputting a drive signal to the actuator; a first tracking error signal generator for generating a first tracking error signal based on an output signal of the photodetector; first and second lens position control sections for respectively outputting first and second lens position control signals to the tracking driver; and a selector for selectively supplying the first tracking error signal to the first or second lens position control section according to a moving velocity of the optical head during a seek operation. The first lens position control signal is obtained by extracting signal components, of which the frequencies are equal to or lower than a predetermined frequency, from the first tracking error signal. The second lens position control signal is obtained by extracting DC components of the first tracking error signal at on-track points thereof.
摘要:
An optical disc reproduction apparatus includes a sector detection section for detecting a sector; a sector reproduction time measuring section for measuring a reproduction time of the sector, and outputting sector reproduction time data which represents the measured reproduction time of the sector; an unrecorded portion detection section for detecting an unrecorded portion which is a portion of the sector in which no data is recorded; an unrecorded portion time measuring section for measuring a reproduction time of the unrecorded portion, and outputting unrecorded portion time data which represents the measured reproduction time of the unrecorded portion; and a sector determination section for determining whether the sector is an unrecorded sector or not, based on a relationship between the sector reproduction time data and the unrecorded portion time data, the unrecorded sector being a sector which is in an unrecorded state.
摘要:
An optical disc drive is used to read and/or write data from/on an optical disc having a data storage layer. The drive corrects electrical offset while reading and/or writing data. The drive updates a correction value based on an electrical offset detected at correcting operation or a value derived using electrical offset values that has been detected and stored, without detecting an electrical offset at correcting operation. Therefore, the optical disc drive can correct the electrical offset less often.
摘要:
A type of disc is judged at high reliability irrespective of a presence of information record or magnitude of disc eccentricity. A reproduction apparatus judges the type of an optical disc to reproduce information recorded on tracks of the optical disc. The disc is classified as a type of read-only optical discs whose tracks are formed with pits and as a type of recordable optical discs whose tracks are formed with wobbling grooves. The apparatus includes a motor which rotates the optical disc, a head which irradiates the tracks of the optical disc rotated by the motor with an optical beam and outputs two detection signals corresponding to reflected light from the optical disc, and a controller which judges the type of the optical disc according to changes of a period of a specific signal contained in a push-pull signal generated from the two detection signals by varying a rotating speed of the motor.
摘要:
An optical disk of the present invention includes a pre-recorded region in which pre-recorded data is recorded; a recordable region in which a first clock synchronization mark and first address information are recorded; and a synchronization region having a prescribed length which is positioned between the pre-recorded region and the recordable region.
摘要:
An optical disc apparatus according to the present invention is usable for an optical disc including a bar code area and a control data area adjacent to the bar code area in a radial direction of the optical disc. The optical disc apparatus includes an optical head for directing an optical beam toward the optical disc so as to form an optical spot on the optical disc and output a signal in accordance with the optical beam reflected by the optical disc; a bar code area determination section for determining whether or not the optical spot is positioned on the bar code area of the optical disc based on the signal output by the optical head; and a control section for controlling the optical head so that the optical spot moves toward the control data area, when the optical spot is determined to be positioned on the bar code area.
摘要:
An optical disk apparatus includes: a light irradiator operable to converge a light beam and irradiate an information carrier with the converged light beam; a traverse motor operable to move the light beam in a direction traversing a track formed on a surface of the information carrier; and a tracking controller operable to control the traverse motor to scan the track with the light beam. The tracking controller includes a deviation detector operable to generate a detection signal, a tracking driving circuit operable to generate a driving signal, an integrator operable to integrate a magnitude of a signal corresponding to the driving signal over a predetermined time period and an abnormal state detector operable to detect an abnormal state of the traverse motor based on an output of the integrator.
摘要:
An optical disk apparatus of the present invention includes: a light irradiator operable to converge a light beam and to irradiate an information carrier (a recording medium) with the converged light beam; a moving means operable to move a converging point of the light beam in a direction substantially perpendicular to a surface of the information carrier; and a focusing controller operable to control the moving means to place the converging point of the light beam at a predetermined position. The focusing controller includes: a converging state detector operable to generate a detection signal corresponding to a converging state of the light beam on the information carrier; a focusing driving means operable to generate a driving signal for driving the moving means based on the detection signal; an integrator operable to integrate a magnitude of a signal corresponding to the driving signal over a predetermined time period; and an abnormal state detector operable to detect an abnormal state of the moving means based on an output of the integrator.
摘要:
An optical apparatus includes a generator for generating a sine wave based on a rotating disc-shaped information carrier, and an eccentricity measuring device for measuring gain and phase of a sine wave corresponding to eccentricity of the information carrier based on the driving signal from the tracking control and on the measured rotation frequency. Also included is a waveform shaper for shaping the gain and phase of the sine wave generated by the sine wave generator using the measured gain and phase obtained by the eccentricity measuring device. An eccentricity correction is applied by adding together the sine wave shaped by the waveform shaper and the driving signal from the tracking control to drive an optical beam on a desired track of the rotating disc.