摘要:
According to one embodiment, an optical information recording medium includes pre-grooves with an irregular shape and lands each of which is sandwiched between the pre-grooves adjacent to each other, where the pre-grooves and lands are defined on an interface between a recording layer and a light reflection layer in a recording film, where the recording film includes a light reflectivity that enables reproduction with light of 650±5 nm, the recording layer includes a recording sensitivity with respect to light by a wavelength shorter than 650±5 nm, and a recording mark can be formed on the pre-groove by using light with a wavelength shorter than 650±5 nm.
摘要:
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.
摘要:
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.
摘要:
According to one embodiment, an optical pickup unit which can record, reproduction and erase information in/from an information recording medium has tracks with different pitches, the dividing means has at least a part of a dividing boundary line placing between an end of a 1st order diffraction light with the largest diffraction angle and an end of a 1st order diffraction light with the smallest diffraction angle of the reflected laser beam.
摘要:
A semiconductor laser driving device includes a current supply unit supplying current to a semiconductor laser; a first control unit controlling the current supply unit to supply a first current which is half or less of a lasing threshold of the semiconductor laser; and a second control unit controlling the current supply unit to supply a second current which is larger than the lasing threshold after a first time is passed from an edge of a clock signal.
摘要:
An embodiment of the invention is useful for providing an optical pickup unit, which condenses light with different wavelengths at different positions and focal distances, and exactly detects a focus error signal when receiving the reflected light with different wavelengths from two or more kinds of recording medium, in the state that the focal distance of a condensing means is the same as the distance from the recording surface of a recording medium to the condensing means, by dividing light with different wavelengths emitted from light sources and reflected by a recording medium into a predetermined number by a diffraction element, and condensing at a position of a predetermined distance in a predetermined direction.
摘要:
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.
摘要:
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.
摘要:
According to one embodiment, an optical pickup unit which can record, reproduction and erase information in/from an information recording medium has tracks with different pitches, the dividing means has at least a part of a dividing boundary line placing between an end of a 1st order diffraction light with the largest diffraction angle and an end of a 1st order diffraction light with the smallest diffraction angle of the reflected laser beam.
摘要:
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.