Olympus Optical Company, Ltd.

Hiroo Okada

Yoshiaki Ikeda

Ken Ohshima

Masaharu Sakamoto

Shohei Kobayashi

Ken Ohsima

Toshio Tsurukawa

Makie Morota

Jun Sakashita

Tasuhiro Miyazaki

An optical pickup is provided below an optical disk. A laser beam is emitted from a semiconductor laser onto a track, through an objective lens. The objective lens is capable of shifting, and is shifted in the direction of the track width by a magnetic force from a tracking actuator, thereby performing lens tracking. The optical pickup is mounted on a carriage. The carriage is shifted along the radial direction of the optical disk by a voice coil motor. This shifts the laser beam along the radial direction of the optical disk, thereby performing track access. Upon reception of an access command, a velocity control mode commences, and the shift velocity of the carriage is controlled in accordance with a velocity control signal corresponding to the distance between a target track and a current track. When the pickup arrives near the target track, the generation of velocity control signal ceases and the location control mode commences. When the carriage is deviated from the target track, its servo is adjusted in accordance with its deviation, by a location control signal. During velocity control of the carriage, a lens damping signal corresponding to the velocity control signal is supplied to the objective lens. After location control of the carriage commences, the lens damping signal corresponding to a location cotnrol signal is supplied to the objective lens until the velocity of the carriage falls below a predetermined value.

Optical recording/reproducing device

A means receiving a light returning from an optical recording medium and detecting the beam distribution in the tangential direction of the track of the recording medium is provided. The offset of at least one controlling signal of a focusing controlling signal and tracking controlling signal is eliminated by the output signal of this beam distribution detecting means.

Optical information recording and reproducing apparatus

An optical recording/reproducing apparatus includes a pickup with a laser light source, an objective lens and lens drive coil for moving the optical axis of the laser beam transmitted through objective lens, a carriage drive voice-coil motor for moving a carriage with the pickup mounted thereon to move the laser beam transmitted through the objective lens, and tracking apparatus for operating both the lens drive coil and the carriage drive voice-coil motor. The tracking apparatus includes a lens servo stable detecting device for detecting that the laser beam from the objective lens has reached a desired track, apparatus for turning on a servo control loop with the lens drive coil in response to a tracking instruction, and apparatus for turning on a servo control loop with the carriage drive voice-coil motor in response to a detection output from the lens servo stable detecting device.

Optical memory accessing and tracking apparatus with pickup and lens

An optical pickup is arranged under an optical disk. Tracks of the disk are irradiated with a laser beam from the pickup. A beam reflected by a given track becomes incident on the pickup. A tracking error signal from the pickup is supplied to a lens moving actuator through a gain phase compensating circuit and a lens driving circuit, and an objective lens in the pickup is radially moved along disk. The tracking error signal is supplied to a voice coil motor through the phase compensating circuit. A carriage carrying the pickup thereon can be radially moved along the disk. When a tracking instruction is generated, the lens driving circuit drives the objective lens to start tracking. Meanwhile, the low-frequency components of the tracking error signal which are lower than the resonance frequency of the lens tracking circuit are amplified by the gain phase compensating circuit. When the tracking error signal is converged within a predetermined threshold range, the amplification of the low-frequency components of the tracking error signal is stopped. At the same time, the operation of the voice coil motor is started. Tracking is performed by both the objective lens and the carriage to achieve two-step servo tracking.

Tracking control apparatus

A beam tracking system is used in an optical information recording and/or reproducing apparatus to optically track a record medium track. An objective lens irradiates an optical beam onto the record medium and is driven by a lens actuator to sweep the optical beam in a coarse mode relative to a predetermined track of the record medium. A carriage moves relative to the record medium for carrying the objective lens thereon and is driven by a carriage actuator to sweep the optical beam in a fine mode relative to the track. A detector detects the reflected optical beam during the sweep of the optical beam to produce a tracking signal representative of the deviation of the optical beam from the track. A pair of control circuits are connected to control the lens and carriage actuators respectively to effect the alignment of the optical beam with the track according to the tracking signal. A timing circuit is coneected to enable operation of the control circuit which controls the lens actuator and to inhibit operation of the other control circuit which controls the carriage actuator for a certain interval to effect alignment of the optical beam solely by means of the lens actuator, and thereafter to enable the other control circuit to maintain the optical beam alignment by means of the cooperative action of the lens and carriage actuators.

Optical beam tracking system for use in optical information recording

A head feed control apparatus for a recording/reproducing system using a disk-like data recording medium with a plurality of concentric tracks thereon includes a linear scale mounted on a head and provided with graduations at predetermined intervals, and a scale detector for reading the graduations of the linear scale. This apparatus performs sampling and access operations. In sampling, the head is moved by a predetermined number of graduations of the scale, and a corresponding address is read to detect the number of tracks of each recording medium zone which corresponds to the predetermined number of graduations and to store (the predetermined number of graduations).div.(the number of tracks) as a zone parameter. In access operation, the head is moved by the number of scale graduations corresponding to (an average value of parameters between a zone where the head is currently located and a zone where a target track is located).times.(the number of tracks between the current and target tracks), and thereafter fine adjustment of the head position is performed.

Head feed control apparatus

A head drive control apparatus has a head and a scale reader. When the head is moved by a head drive mechanism, the scale reader detects the marks on a scale and converts them into a scale signal. In a speed control mode, the scale signal is compared with a target signal by an access signal generator, which produces an access signal representing the difference between the compared signals. The head is moved in accordance with the access signal until the scale signal becomes identical with the target signal. When these signals become equal, the speed control mode is switched to a position control mode. In the position control mode, a scale signal generator, a pulse generator, an up/down counter, a D/A converter, an adder and an interpolator convert the scale signal into an analog signal which represents the position of the head. The analog signal is compared with a position designating signal by a differential amplifier. The head is moved in accordance with the output signal of this amplifier.

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Ina, Japan

Hiroo Okada