Patent application number | Description | Published |
20080205212 | OPTICAL HEAD APPARATUS, INFORMATION RECORDING/REPRODUCING APPARATUS INCLUDING THE OPTICAL HEAD APPARATUS, AND INFORMATION RECORDING/REPRODUCING METHOD - According to one embodiment, an optical head device provides a signal processing circuit which sets a control amount to move an objective lens so that a distance between the objective lens and a given recording layer of the an optical disc coincides with a focal position, an optical path length correction mechanism which corrects an influence of an aberration component producing an error in the focal distance, a thickness difference detection circuit which finds an amount of correction to be made by the optical path length, and an aberration correction circuit which generates a correction signal to correct the influence of the aberration component producing the error in the focal distance detected by the thickness difference detection circuit, and supplies the correction signal to the optical path length correction mechanism. | 08-28-2008 |
20080205216 | INFORMATION RECORDING APPARATUS CAPABLE OF RECORDING INFORMATION IN INFORMATION RECORDING MEDIUM, INFORMATION RECORDING METHOD, AND TARGET VALUE DETERMINING METHOD - According to one embodiment, an apparatus which records a signal in a recording medium in which information is written by using a first laser having a first wavelength and from which information is read by using a second laser having a second wavelength longer than that of the first laser, a signal is recorded in the recording medium by using the first laser, and a control section reproduces the signal recorded with the first laser and measures a first amount that is used to calculate a target value for optimization of recording conditions, reproduces a signal recorded with the second laser and measures a second amount for optimization of a reproduction signal, compares the first amount with the second amount, and determines the first amount under the recording conditions where the second amount becomes optimum as a target value for optimization of the recording conditions. | 08-28-2008 |
20090103422 | OPTICAL RECORDING HEAD DEVICE, OPTICAL RECORDING APPARATUS, AND RECORDING METHOD - According to one embodiment, an optical recording head device includes a light source which outputs such a relaxation oscillation optical pulse that a full width at half maximum of a single pulse is 820 ps or less, a driving unit for driving the light source, an objective lens which converges emission light from the light source on a recording layer of a recording medium, and captures reflective light which is reflected by the recording layer of the recording medium, a distribution unit, placed between the light source and the objective lens, for distributing incident light, and a photodetection unit for receiving via the distribution unit the reflective light which is reflected by the recording layer of the recording medium, wherein a resonator length of the light source is 6560 μm or less. | 04-23-2009 |
20090109808 | OPTICAL HEAD DEVICE AND INFORMATION - According to one embodiment, a laser drive circuit which supplies a drive current to a laser element which outputs light at a predetermined wavelength, and a laser control circuit which supplies a predetermined timing pulse for generation of relaxation oscillation in a laser drive current supplied to the laser drive circuit, the laser control circuit supplying a laser drive current higher than a threshold value which is supplied from the laser drive circuit to the laser element to enable laser light to be output from the laser element, the laser control circuit setting the laser drive current to a level lower than the threshold value on the basis of the timing pulse. | 04-30-2009 |
20090109809 | LASER DRIVE DEVICE AND INFORMATION RECORDING/REPRODUCING APPARATUS USING THE DEVICE - According to one embodiment, a laser drive circuit includes a photodetector which receives part of laser light emitted from a laser element to a recording medium independently of reflection laser light reflected by the recording medium, and outputs an output corresponding to the strength thereof, an integration circuit which integrates the output from the photodetector for a predetermined time, and a setting circuit which sets the intensity of a laser drive current supplied to the laser element on the basis of the output from the integration circuit. | 04-30-2009 |
20090109815 | OPTICAL DISC DEVICE AND OPTICAL DISC PROCESSING METHOD - According to one embodiment, an optical disc device includes a light source portion which applies laser light to an optical disc, a drive portion which supplies a drive current to the light source portion so as to cause the light source portion to apply laser light of light pulses having relaxation oscillation, and a controller which controls the drive portion to supply a drive current so as to cause the light source portion to emit laser light of (n−1)×N (N is an integral number) light pulses having relaxation oscillation with respect to a mark with recording mark length nT (n: integral number, T: channel clock) to be recorded on the optical disc. | 04-30-2009 |
20090109816 | OPTICAL DISC APPARATUS AND OPTICAL DISC PROCESSING METHOD - According to one embodiment, a calibration section controls an LD driving section so as to carry out test writing on a recording layer of an optical disc using a light pulse having relaxation oscillation, irradiates the test-written area with a reproduction laser beam so as to detect reflected light, and determine write strategy based on the detected result. A recording process is executed on the optical disc by using the light pulse having relaxation oscillation based on the write strategy determined by the calibration section. | 04-30-2009 |
20090141760 | DRIVE CONTROL APPARATUS AND DRIVE CONTROL METHOD OF SEMICONDUCTOR LASER - According to one embodiment, a drive control apparatus of a semiconductor laser includes a driving circuit which drives the semiconductor laser by applying pulses transiting from bias current to peak current to the semiconductor laser as laser driving current that causes relaxation oscillation of emission light intensity of the semiconductor laser, and a control circuit which controls the bias current such that the bias current has a predetermined ratio limiting fluctuation of a leading peak value of the relaxation oscillation occurring for each application of pulses relative to threshold current of the semiconductor laser. The control circuit changes the bias current to maintain the predetermined ratio relative to fluctuation of the threshold current. | 06-04-2009 |
20090196138 | INFORMATION RECORDING APPARATUS AND CONTROL METHOD THEREOF - According to one embodiment, in one embodiment of the invention, a laser drive circuit is provided with a first current source, a second drive current source, and a third current source. The control section selectively obtains a plurality of laser light use mode of controlling the from first to third current sources to use pulse laser light accompanying relaxation oscillation, and a complex laser light use mode of using laser light where laser pulses are combined, whose starting end has an abrupt impulse change portion caused by relaxation oscillation and whose intermediate section is a flat portion with a fixed intensity. | 08-06-2009 |
20090196142 | INFORMATION RECORDING MEDIUM, INFORMATION RECORDING METHOD, AND INFORMATION RECORDING AND REPRODUCING APPARATUS - According to one embodiment, in an information recording medium for which a phase change material is used and in which information is recorded on, reproduced from, and erased from a recording layer by light irradiation, a recrystallization width WR at a periphery of an amorphous recording mark formed on the recording layer by light irradiation, and a recording mark width WA and a track pitch TP satisfy 1.008-06-2009 | |
20090196148 | MASTER RECORDING APPARATUS AND MASTER RECORDING METHOD - According to one embodiment, the invention provides a master recording apparatus and method which can form a pit having a symmetrical pit shape with excellent reproducibility. An embodiment of the invention is a master recording apparatus where a resist film on a master for an optical disk is irradiated with irradiation light from a semiconductor laser to record information on the resist film, where the resist film is formed as an inorganic resist film, and means for outputting the irradiation light from the semiconductor laser as a short pulse laser with a pulse width between 200 ps and 1 ns is provided. | 08-06-2009 |
20100135436 | SIGNAL PROCESSING SYSTEM AND INFORMATION STORAGE MEDIUM - According to one embodiment, a first encoder encodes main information, a second encoder encodes sub-information, a first modulator modulates a carrier based on an output of the first encoder, a duplicating module duplicates an output of the second encoder to generate encoded sub-information units, and a second modulator amplitude-modulates an output of the first modulator based on the encoded sub-information units. The second modulator amplitude-modulates with σ/(μ×(2 | 06-03-2010 |