摘要:
An information recording medium has a recording track, a plurality of address areas which are formed on the recording track and record address information, and mark areas, the number of which is larger than the number of address areas, and which are formed at predetermined intervals and include mark information. Each address area records address information by means of pits, and each mark area records mark information by means of wobbles as a part of a track boundary.
摘要:
Header regions are formed by dividing a groove or grooves. Each of the header regions is provided with two ID sections G-ID1, G-ID2 storing address information and a track center detection mark section, arranged between the two ID sections, so as to be used for detecting the track center.
摘要:
User data recording areas and intermediate areas are alternately arranged on a disk. The intermediate area records at least information for synchronization.
摘要:
An information storage medium (1) has tracks in which information is recorded. The tracks are formed as a groove section (2) and a land section (3). The groove section (2) has a synchronous structure in which wobbles (2a) and (2b) formed on both walls of the groove section (2) are not displaced from each other in the circumferential direction of the medium, and the land section (3) has an asynchronous structure in which wobbles formed on both sides of the land section (3) are displaced from each other. A good signal is reproduced from each of the groove and land sections.
摘要:
User data recording areas and intermediate areas are alternately arranged on a disk. The intermediate area records at least information for synchronization.
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, 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, 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×(2N)1/2) being 0.4 or less, wherein a noise power of a transmission path or a storage medium is σ2, a number of the encoded sub-information units is N, signal levels after amplitude modulation, which correspond to bit 1 and bit 0 of the encoded sub-information units, are A and B, and a level difference A−B is μ.
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.