Abstract: The present invention solves the problems that, in a detection circuit which is mostly configured by analog circuits, the chip size cannot be reduced even using a highly-precise processing, there are many external capacitors and terminals thereof, a plurality of high-speed and large-scale AD converters are required for digitization, the detection precision of a small amplitude signal superimposed on an RF signal is deteriorated, and high-speed sample/hold is required. A significant deletion of analog circuits can be realized by generating a digital detection signal directly from an analog RF signal using a simple analog circuit configuration of a detection control means including a comparator, a threshold DAC for setting a threshold value, and an integrator.

Abstract: In a repetitive control device used for processing a servo signal, a memory (7) is used as a delay element for a filter (6), and a filtering process by the filter (6) is carried out using a clock signal that is an integral multiple of an operation frequency of a driving signal. Therefore, the gain can be increased without generating phase rotation with respect to a compensated signal, and high followability can be achieved to fluctuations in the track position which are caused by the shape of a disc such as decentering or surface wobbling, during recording and playback in an optical disc device.

Abstract: According to the present invention, a moving element such as an electrostatically driven actuator is displaced by supplying a drive signal thereto. Meanwhile, a displacement sensing section senses its displacement and a calibrating section automatically calibrates the correlation between the drive signal and the displacement, thereby compensating for a variation in the characteristic of the actuator with time and according to the environment. A switching section selectively connects the single displacement sensing section to a plurality of moving elements one after another, thereby cutting down the circuit for displacement sensing.

Abstract: The precision of a direction detection signal DIR is judged from the duty ratio of the direction detection signal DIR, and the direction detection signal DIR which is used for track search control or tracking pull-in control is judged as valid or invalid according to the precision, thereby to improve the precision of the track search control or the tracking pull-in control. Therefore, even when the direction detection is not performed accurately due to a difference in the reflected light quantity on the optical disk, a defect on the optical disk, a delay in the track cross speed during search, or a delay in the detection circuit, the track search control and the tracking pull-in control can be performed with stability.

Abstract: A seat slide for a vehicle, including a lower rail fixed to a floor of the vehicle, an upper rail fixed to a seat of the vehicle, a lock plate disposed within an inner space between the lower and upper rails and secured to the lower rail, a latch lever with a pawl which is disposed within the inner space and pivotally supported by the upper rail, and a position sensor for detecting a position of the upper rail relative to the lower rail, the position sensor being mounted to the upper rail such that a sensing portion thereof is disposed within the inner space and opposed to the lock plate.

Abstract: A phase error detection apparatus capable of performing offset correction of a tracking error signal accurately even when there is a defect or a non-recorded position on an optical disc. There are provided a phase difference detection circuit (107) which receives two sequences of digital signals, performs phase comparison using a distance between zerocross points of the two sequences of digital signals, and outputs a phase comparison result PCR and a phase comparison completion signal PCC, and an offset control circuit (11) which outputs an offset correction amount for each phase comparison completion signal PCC from the phase difference detection circuit (107), and the offset correction amount ?? is added to the phase comparison result PCR to avoid offset correction in a position where phase comparison is not carried out.

Abstract: An information playback apparatus comprises an input amplifier to which an RF signal reproduced from an optical disc is input; a high-pass filter to which the output of the input amplifier is input; an AD converter to which the output of the high-pass filter is input; a lag lead filter to which the output of the AD converter is input; and a demodulator for digitally processing the output of the lag lead filter to demodulate it as a binary signal. Thereby, an optical disc playback apparatus that realizes a DVD-RAM playback function at low cost can be realized.

Abstract: A laser power control circuit that is constituted by CMOS transistors reduces variations in a laser power that is emitted from a semiconductor laser, which are caused by a mismatch of the transistors. An offset amount of a differential amplifier is digitally calculated using an A/D converter that is located on the same chip, and a voltage value of a variable voltage source is controlled for applying a voltage in a direction opposite to the offset voltage of the differential amplifier to correct the offset voltage of the laser power control circuit, thereby reducing the variations in the laser power emitted from the semiconductor laser.

Abstract: To greatly increase the storage density of a storage apparatus, an electron beam E emitted from a cold cathode 101 is accelerated by an accelerating electrode 102, caused to converge by a convergence electrode 103, deflected by a deflection electrode 104 and applied to a minute region of a storage film 105. The storage film 105 includes, for example, a phase change film 105a. The film is rapidly heated and cooled to change into an amorphous state upon irradiation with an electron beam E with high energy, while being gradually cooled to change into a crystallized state upon irradiation with an electron beam E with approximately intermediate energy, thereby storing data. Upon irradiation with an electron beam E with low energy, the potential difference between a detection electrode 105b and an anode 105c is detected depending on the state, i.e., the amorphous or crystallized state, thereby reading stored data.

Abstract: In a recordable data storage medium on which property data was recorded after having been modulated and on which data that is decodable by a cryptographic key to be generated from the property data was recorded, the property data was preferably modulated by a different method from that applied to a read-only data storage medium. Then, an optical disc drive, having no ability to distinguish the recordable data storage medium from the read-only data storage medium, cannot read the recordable data storage medium. Consequently, a greater number of drives should be equipped with the function of recognizing the type of a given data storage medium and the copyright protection function should be consolidated.

Abstract: In a recordable data storage medium on which property data was recorded after having been modulated and on which data that is decodable by a cryptographic key to be generated from the property data was recorded, the property data was preferably modulated by a different method from that applied to a read-only data storage medium. Then, an optical disc drive, having no ability to distinguish the recordable data storage medium from the read-only data storage medium, cannot read the recordable data storage medium. Consequently, a greater number of drives should be equipped with the function of recognizing the type of a given data storage medium and the copyright protection function should be consolidated.

Abstract: According to the present invention, a moving element such as an electrostatically driven actuator is displaced by supplying a drive signal thereto. Meanwhile, a displacement sensing section senses its displacement and a calibrating section automatically calibrates the correlation between the drive signal and the displacement, thereby compensating for a variation in the characteristic of the actuator with time and according to the environment. A switching section selectively connects the single displacement sensing section to a plurality of moving elements one after another, thereby cutting down the circuit for displacement sensing.

Abstract: According to the present invention, a moving element Ai such as an electrostatically driven actuator is displaced by supplying a drive signal thereto. Meanwhile, a displacement sensing section 6 senses its displacement and a calibrating section 15 automatically calibrates the correlation between the drive signal and the displacement, thereby compensating for a variation in the characteristic of the actuator with time and according to the environment. A switching section 7 selectively connects the single displacement sensing section to a plurality of moving elements Ai one after another, thereby cutting down the circuit for displacement sensing.

Abstract: A servo error signal generation circuit comprises a first sampling unit for sampling first detection signals at first sampling timings, a second sampling unit for sampling second detection signals at second sampling timings which are obtained by periodically thinning out the first sampling timings, an AD converter for analog-to-digital converting the data sampled by the first and second sampling units, and a completion unit for completing the sampling date of the timings which have been thinned out by the sub sampling timing generator, for the data which have been sampled by the second sampling unit and outputted from the AD converter.

Abstract: In a repetitive control device used for processing a servo signal, a memory (7) is used as a delay element for a filter (6), and a filtering process by the filter (6) is carried out using a clock signal that is an integral multiple of an operation frequency of a driving signal. Therefore, the gain can be increased without generating phase rotation with respect to a compensated signal, and high followability can be achieved to fluctuations in the track position which are caused by the shape of a disc such as decentering or surface wobbling, during recording and playback in an optical disc device.

Abstract: A tracking error detection apparatus comprises a phase difference detection circuit for receiving two sequences of digital signals, and performing phase comparison using a distance between zerocross points of the two sequences of digital signals to output a result of phase comparison, and an LPF for generating a tracking error signal from the result of phase comparison. The phase difference detection circuit does not carry out phase composition in a position that is not appropriate as a target position to perform phase comparison, and outputs the result of phase comparison as a pulse signal corresponding to one sampling clock. Therefore, even when a disc is played at CAV or a flaw or the like exists on the disc, an accurate tracking error signal can be detected.

Abstract: In a recordable data storage medium on which property data was recorded after having been modulated and on which data that is decodable by a cryptographic key to be generated from the property data was recorded, the property data was preferably modulated by a different method from that applied to a read-only data storage medium. Then, an optical disc drive, having no ability to distinguish the recordable data storage medium from the read-only data storage medium, cannot read the recordable data storage medium. Consequently, a greater number of drives should be equipped with the function of recognizing the type of a given data storage medium and the copyright protection function should be consolidated.

Abstract: 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.

Abstract: In a recordable data storage medium on which property data was recorded after having been modulated and on which data that is decodable by a cryptographic key to be generated from the property data was recorded, the property data was preferably modulated by a different method from that applied to a read-only data storage medium. Then, an optical disc drive, having no ability to distinguish the recordable data storage medium from the read-only data storage medium, cannot read the recordable data storage medium. Consequently, a greater number of drives should be equipped with the function of recognizing the type of a given data storage medium and the copyright protection function should be consolidated.

Abstract: A laser power control circuit that is constituted by CMOS transistors reduces variations in a laser power that is emitted from a semiconductor laser, which are caused by a mismatch of the transistors. An offset amount of a differential amplifier is digitally calculated using an A/D converter that is located on the same chip, and a voltage value of a variable voltage source is controlled for applying a voltage in a direction opposite to the offset voltage of the differential amplifier to correct the offset voltage of the laser power control circuit, thereby reducing the variations in the laser power emitted from the semiconductor laser.