Abstract: It is desired that the overshooting and undershooting of optical pulse waveforms of optical pickups included in optical disk devices be reduced to improve the quality of recording. Among pulses to be recorded, the trailing edge of each last pulse and the leading edge of the subsequent erase top pulse are made to almost coincide with each other. Ratio a/b, where a is the difference between erase top pulse power level Pet and erasing power level Pe and b is the difference between recording power level Pw and the erasing power level Pe, is adjusted to realize an optical pulse waveform with reduced overshooting and undershooting for each of different recording media. Erase top pulse duration Tert is switched according to different recording speeds for different recording media.

Abstract: It is desired that the overshooting and undershooting of optical pulse waveforms of optical pickups included in optical disk devices be reduced to improve the quality of recording. Among pulses to be recorded, the trailing edge of each last pulse and the leading edge of the subsequent erase top pulse are made to almost coincide with each other. Ratio a/b, where a is the difference between erase top pulse power level Pet and erasing power level Pe and b is the difference between recording power level Pw and the erasing power level Pe, is adjusted to realize an optical pulse waveform with reduced overshooting and undershooting for each of different recording media. Erase top pulse duration Tert is switched according to different recording speeds for different recording media.

Abstract: In order to ensure recording quality while suppressing the adverse effects due to performance variations among apparatuses and disc radial positions on an optical disc, an optical disc apparatus according to the present invention performs, at the time of data recording, the steps of: acquiring a jitter value and ? value from a reproduced signal based on laser light reflected from the optical disc in relation to a disc radial position; learning a ? value when the acquired jitter value is a minimum as a target ? value; and, if a jitter value acquired thereafter is larger than the minimum jitter value by a preset reference value or above, correcting recording power based on the magnitude relation and the difference between the ? value associated with the acquired jitter value and the target ? value or performing trial record processing.

Abstract: There is provided an information recording and reproducing method and an apparatus for the same capable of optimizing the shift adjustment of a recording pulse recorded in an optical disk even at the time of recording information on the optical disk at a high speed. The shift adjustment value of the recording pulse optimized at a low speed recording on an optical disk is multiplied by a constant value to be taken as the optimum shift conditions of the recording pulse at the high speed recording.

Abstract: In a focus controlling method of a laser beam for an optical disk, achieving a stable focus drawing-in, lowering ill influences due to stray lights, detecting an electric signal, which is obtainable upon basis of a reflection light from the optical disk loaded, in advance, while executing a focus sweep operation of gradually approaching the laser to a recoding surface of the optical disk, at an unnecessary light detection gain being higher than a gain of normal operation, thereby counting a number of signals generated due to unnecessary lights; and thereafter, detecting the electric signal, which is obtainable upon basis of the reflection light from the optical disk loaded, and thereby conducting a focus drawing-in, by considering an electric signal, which is generated just after a number detected thereof reaches to the counted number of signals generated due to the unnecessary lights, to be a signal reflected from the recording surface of the optical disk loaded.

Abstract: There is provided an information recording and reproducing method and an apparatus for the same capable of optimizing the shift adjustment of a recording pulse recorded in an optical disk even at the time of recording information on the optical disk at a high speed. The shift adjustment value of the recording pulse optimized at a low speed recording on an optical disk is multiplied by a constant value to be taken as the optimum shift conditions of the recording pulse at the high speed recording.

Abstract: In order to ensure recording quality while suppressing the adverse effects due to performance variations among apparatuses and disc radial positions on an optical disc, an optical disc apparatus according to the present invention performs, at the time of data recording, the steps of: acquiring a jitter value and ? value from a reproduced signal based on laser light reflected from the optical disc in relation to a disc radial position; learning a ? value when the acquired jitter value is a minimum as a target ? value; and, if a jitter value acquired thereafter is larger than the minimum jitter value by a preset reference value or above, correcting recording power based on the magnitude relation and the difference between the ? value associated with the acquired jitter value and the target ? value or performing trial record processing.

Abstract: In an optical disk apparatus and a method for determining the recording power for the same, for determining the optimum value of a laser power when recording data onto a high density optical disk, a test signal is recorded with changing the recording power Pw while fixing an erasing power Pe. Reproduction is made on the signal recorded so as to obtain a “?” value indicative of asymmetry of the reproduction signal to each the recording power. In this instance, the “?” value, or the optimal recording power Pwo is determined, with utilizing an area or region, being called APC region, which is provided in a part of the recording regions, which are divided into a large number thereof, each being made of a predetermined information recording unit (RUB), being unique to that disk, and further equalization thereof. Herein, the erasing power Pe to be fixed is determined from a result of measurement on a modulation factor, “M” value while recoding another test signal.

Abstract: In a focus controlling method of a laser beam for an optical disk, achieving a stable focus drawing-in, lowering ill influences due to stray lights, detecting an electric signal, which is obtainable upon basis of a reflection light from the optical disk loaded, in advance, while executing a focus sweep operation of gradually approaching the laser to a recoding surface of the optical disk, at an unnecessary light detection gain being higher than a gain of normal operation, thereby counting a number of signals generated due to unnecessary lights; and thereafter, detecting the electric signal, which is obtainable upon basis of the reflection light from the optical disk loaded, and thereby conducting a focus drawing-in, by considering an electric signal, which is generated just after a number detected thereof reaches to the counted number of signals generated due to the unnecessary lights, to be a signal reflected from the recording surface of the optical disk loaded.

Abstract: An optical disk apparatus, enabling effective protection from mal functions due to the radio-waves entering inside the apparatus from an outside thereof, comprises a housing 10, a tray 20, which can be inserted/discharged into the housing through an opening portion 12 thereof, a disk motor 50, which is provided in a part of the tray, for driving an optical disk rotationally, an optical pickup 30, which is also provided in a part of the tray, for recording and/or reproducing information with using an optic beam, a signal processing circuit board 40, which is provided in a part of the housing on the other hand, for processing a signal from the optical pickup mounted on the tray, wherein a flexible wiring sheet 100 or 200 is disposed in a part thereof, while being curved, and further an absorbing member 300 or 400 for radio-waves is provided at a position in vicinity of the curved portion 110 or 210, thereby lowering resonances of electromagnetic waves within an inside of the housing, in particular, in the verti

Abstract: A high voltage variable resistor section (8) for deriving the focusing voltage and screen is attached to an open portion formed on one surface of a first case (47) which receives primary and secondary windings (2, 3) included in a flyback transformer section (1). An insulating substrate (16) on which resistor elements (9-13) included in the high voltage variable resistor section are formed in housed in a second case (15). An opening is formed in one surface of the second insulating cases (15). With this opening communicating with the opening in the first insulating case, the two insulating cases are integrated. These insulating case define insulating case means, in which a high voltage capacitor (14) for compensating cathode ray tube capacity is housed.