Funai Electric Company Ltd.

Kazuki Kajikawa

Toshiaki Fukui

Futoshi Takeda

Kazuto Kitagawa

Kazuhiro Ichikawa

The optical disc device includes an optical pickup, a focus-error-signal generation section for generating a focus error signal of the differential astigmatic method by using a parameter and an electric signal outputted from a photodetector in the optical pickup, a control section for controlling the optical pickup to make a focus jump operation, and a parameter value changing section for temporarily changing a value of the parameter to be used to generate a focus error signal of the differential astigmatic method by the focus-error-signal generation section when the focus jump operation is performed by using the focus error signal of the differential astigmatic method.

Optical disc device and focus jump method

An optical disc apparatus includes an optical pickup, a signal generation section which generates a total reflection signal and a focus error signal, and a servo control section which controls optical pickup. The optical disc apparatus further includes a main control section which binarizes the track cross signal by using a predetermined threshold value and, by using the binarized track cross signal, checks the tracing state of a track. The main control section controls the servo control section to check, by tracing one turn of the track of an optical disc, whether or not a tracking servo deviation occurs. When a tracking servo deviation occurs during the tracing, the main control section controls the servo control section to make the check once again. When, in the check made once again, a tracking servo deviation is found to occur again, the main control section increases the threshold value used in binarization.

Optical disc apparatus

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.

Optical disk device

A control portion instructs supply of an offset voltage while a disk remains stopped at the time of start. While the disk remains stopped at the time of start, a differential operational amplifier detects a voltage difference between a first voltage supply line and a second voltage supply line. When the absolute value of the voltage difference output by the differential operational amplifier is equal to or lower than a prescribed threshold value, a failure determination portion determines that a spindle motor has shorted out.

Disk apparatus capable of determining failure of spindle motor

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

A disc apparatus which can accurately judge 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 detects a difference between voltages of a positive terminal and a negative terminal of the spindle motor () as a detecting voltage level, a failure judgment unit () which judges whether or not the spindle motor () is at fault based on the detecting voltage level, and a disc determination means () which determines a type of the disc (). The failure judgment unit () judges that the spindle motor () is at fault when the detecting voltage level becomes lower than a predetermined threshold level five times continuously during a start-up that the spindle motor () starts driving when the disc () is in stopped state while the disc determination means () determines the type of the disc (). Consequently, the failure judgment unit () can accurately judge the failure in the spindle motor () without extending the start-up time.

Growing community of inventors

Osaka, Japan

Kazuki Kajikawa