Funai Electric Company Ltd.

Toshiaki Fukui

Kazuki Kajikawa

Hideyuki Tanaka

Yasunori Kuwayama

Futoshi Takeda

Kazuhiro Ichikawa

Kazuto Kitagawa

Hisayuki Negishi

An optical scanning device includes a light source component, a scanning component, an electrostatic driver, a controller, and a current sensor. The light source component emits light. The scanning component scans the light. The driver drives the scanning component. The controller controls emission of the light from the light source component. The current sensor senses current generated by a capacity change of the driver. The controller further controls the emission of the light from the light source component based on the sensed current sensed by the current sensor.

Optical scanning device

This optical disk device includes a pickup, an offsetting means, a focus servo means, a layer jump means, and a shift means. The pickup irradiates laser light upon an optical disk having a plurality of recording layers via a correction lens and an objective lens, and detects light reflected back from the optical disk. The offsetting means generates a focus error (FE) signal on the basis of the reflected light, and applies an offset voltage to the focus error signal. The focus servo means performs focusing servo on the basis of the FE signal. And, before layer jumping is executed by the layer jump means, the focus servo means displaces the correction lens to an intermediate position after having adjusted the offset voltage to a balance value. Then the layer jump means performs layer jumping.

Optical disk device

This optical disk device includes a pickup, an offset means, a focus servo means, and a layer jump means. The offset means generates a focus error signal on the basis of the output of the pickup, and applies an offset voltage to that focus error signal. And the layer jump means performs layer jump operation, including kick start operation, kick end operation taking a second threshold value as a reference, brake start operation taking a third threshold value as a reference, and brake end operation. Moreover, before executing this layer jump operation, the layer jump means changes this second threshold value or this third threshold value, according to the value of the offset voltage.

An optical disc playback apparatus with which collision of a lens and an optical disc is avoided is provided. Processes executed by a microcomputer of the optical disc playback apparatus when a disc is played back include: the step of outputting a signal for performing focus search at a predetermined speed; the step of outputting a signal for reducing search speed when reflection of laser light from a surface of the optical disc is detected; and the step of outputting a signal for indicating disc error when S-shape is not detected and a certain time has elapsed since the detection of the reflection.

Optical disc playback apparatus

A disc apparatus which can judge accurately whether or not a spindle motor is at fault due to a short circuit is provided. A disc apparatus () includes a spindle motor () which rotates a disc (), a differential operational amplifier () which successively detects output voltages of the spindle motor (), and a failure judgment unit () which calculates an average voltage of the plural output voltages and judges whether or not the spindle motor () is at fault in accordance with the average voltage and the output voltages. When counting number of occurrences of a specific state which indicates that one of the two output voltages detected successively is larger than the average voltage and other of the two output voltages is smaller than the average voltage, the failure judgment unit () judges that the spindle motor () is at fault. Consequently, the failure judgment unit () can rapidly and accurately judge the failure in the spindle motor () without the influence from the unexpected change of the output voltages.

Disc apparatus

When a remaining number of tracks is smaller than a first threshold value, a coarse seek operation is determined to be normal, and therefore, a learning process is not executed. If the remaining number of tracks is not smaller than a second threshold value, the coarse seek operation is determined to be abnormal, and a voltage learning process id executed. If the remaining number of tracks is not smaller than the first threshold value and smaller than the second threshold value and prescribed conditions are satisfied, the operation is determined to be abnormal, and a time learning process is executed.

Optical disk device performing high-speed seek operation and optical disk device seeking method

There is provided an optical disk device that performs a focus jump operation in a stable and prompt manner. The optical disk device includes an objective lens, a light-detecting element, a lens holder, a shaft member configured to penetrate a hole, a focus drive mechanism, a focus drive circuit, a tracking rotation mechanism, a tracking drive circuit, and a control circuit. The control circuit includes a drive control portion, a wobble control portion, and a switch portion. The drive control portion generates a control signal to be input to the focus drive circuit and a control signal to be input to the tracking drive circuit. The wobble control portion generates a control signal indicating that a current value should fluctuate. During a period of focus jump, the switch portion introduces into the tracking drive circuit the control signal generated by the wobble control portion.

A disc apparatus which enables an optical pickup to move swiftly to a target track is provided. A disc apparatus () includes an optical pickup () which irradiates an optical disc () with a laser light, a motor () which moves the optical pickup () to a target track in a radial direction of the optical disc (), and a controller () which controls the motor (). The controllerincludes a calculating means () which calculates a voltage level applied to the motor () and a recording unit () which records a reference voltage level, a corrected number of tracks, and a coefficient. The calculating means () calculates a voltage level based on the number of tracks between a track which the optical pickup is positioned over and the target track, the reference voltage level, the corrected number of tracks, and the coefficient. The controller () moves the optical pickup () widely to a position close to the target track by driving the motor () at the voltage level which is calculated by the calculating means (). Consequently, the controller () can move the optical pickup () to the target track swiftly.

A bandpass filter receives a tracking error signal. An average/minimum frequency measurement circuit repeats measurement prescribed times, of an average frequency and a minimum frequency of a signal output from the bandpass filter. A standard deviation calculation circuit assumes the average frequency and the minimum frequency obtained by prescribed times of measurement as one variate, and calculates a standard deviation of this variate. A determination circuit determines an optical disc to be reproduced as a read-only optical disc when the standard deviation is equal to or larger than a prescribed value, while it determines the optical disc to be reproduced as a recordable optical disc when the standard deviation is smaller than the prescribed value.

Optical disc reproduction apparatus determining whether optical disc to be reproduced is read-only or recordable

In an optical disc apparatus reading and writing data with respect to an optical disc, a motor controller uses widest pattern signals outputted from an optical pickup for judging size of an optical disc mounted on a turn table and stop of rotation of the optical disc. Since an inverse number of the widest pattern signal has correlation with a frequency sensed by a conventional frequency generator, the motor controller calculates a difference between inverse numbers of the widest pattern signals before and after putting braking force to the turn table, and judges the size of the optical disc with reference to variation of rotation speed before and after the braking. The motor controller further calculates a prediction time when the rotation of the optical disc will be stopped with using the variation of the inverse number of the widest pattern signal, stops to put the braking force to the turn table at the prediction time, and judges the rotation of the optical disc has been stopped.

Optical disc apparatus

An optical disc apparatus has a crosstalk level determining section which, when a track jump is performed without applying a tracking servo, determines whether a crosstalk component is larger than a predetermined level or not. If the crosstalk level determining section determines that the crosstalk component is larger than the predetermined level, a crosstalk correcting section performs a calculation for reducing the crosstalk component. If the crosstalk level determining section determines that the crosstalk component is not larger than the predetermined level, the crosstalk correcting section does not reduce the crosstalk component.

In an optical disc apparatus for recording and/or reproducing data on an optical disc, a lens holder for holding an objective lens is dynamically moved not only in a direction perpendicular to a data recording face of an optical disc but also in a direction parallel to the data recording face and crossing substantially at right angle with data recording tracks on the data recording face when the optical disc is loaded on the optical disc apparatus so as to remove the sticking of the movement of the objective lens due to adhesion of dust, break or deformation of the components.

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Osaka, Japan

Toshiaki Fukui