摘要:
An optical disk of the present invention includes a transparent dielectric film formed on a light incident side of the disk on an opposite side of an optical recording film so as to sandwich the transparent substrate therebetween, for suppressing bimetallic effects caused by a difference in thermal expansion between an optical recording film formed on an optical recording surface and the transparent substrate, whereby changes in tilt against temperature changes can be suppressed. Further, by an optimal selection of a reflectance of the transparent dielectric film, unwanted reflection due to multi-interference can be reduced at the same time.
摘要:
An optical disk has address recording sections each of which has a wobbled part of one of side walls of a groove. Each address recording section is formed by providing convexes of a groove in an adjacent land so as to widen the groove. With the wobbles thus provided in a concavo-convex form, address information is recorded. Besides, the address recording sections thus provided in the grooves are linearly disposed in radial directions of the optical disk. By thus arranging the optical disk on whose grooves and/or lands information is recorded, mixing of wobble frequency components in reproduced information signals does not occur, the sector method is applicable to the optical disk, and information signals of high quality can be obtained.
摘要:
A magneto-optical recording medium having a substrate whereupon a transparent dielectric layer, a readout layer showing in-plane magnetization at room temperature and perpendicular magnetization with an increase in temperature, a metal film layer, a recording layer made of a perpendicularly magnetized film, and a protective layer are formed in this order, wherein the film thickness of the readout layer is between 5 nm and 30 nm, the film thickness of the metal film layer is between 6 nm and 40 nm, and the film thickness of the recording layer is between 20 nm and 80 nm. Since recording domain information at a portion showing in-plane magnetization is masked, even when adjacent recording bit enters into the beam diameter of a light beam focused, it is possible to separately reproduce individual recording bits with high signal quality.
摘要:
A magneto-optical recording medium comprising a reproducing magnetic layer having a magnetic layer which is in an in-plane magnetization state at room temperature but shifts to a perpendicular magnetization state as temperature rises, a dielectric layer and a recording magnetic layer having a magnetic layer which exhibits a perpendicular magnetization, sequentially from a photo-receptive side, the recording medium being further comprising a metal layer between the reproducing magnetic layer and the dielectric layer.
摘要:
An optical disk is provided with a recording layer, and with an optical coupling layer on a light-incident side of the recording layer. An optical recording and reproducing device and method include an objective lens and a hemispherical lens, which converge a light beam from a light source and project the light beam onto the optical disk. The hemispherical lens is provided in close proximity to the optical coupling layer, in a position such that an interval therebetween is not more than the wavelength of the light produced by the light source. The light beam converged by the objective lens and the hemispherical lens is coupled with the optical coupling layer while substantially maintaining a direction of propagation in which it was propagating while inside the hemispherical lens.
摘要:
An optical disk substrate in which a winding groove, which is winding in accordance with address information, and a normal groove, which is not winding, are placed alternately in the radial direction as tracking guides used for tracking control. With respect to this optical disk substrate, a laser beam, which is used for forming patterns for the tracking guides, is applied while being switched alternately between the first mode that exerts oscillations in the disk radial direction in accordance with the address information and the second mode that does not exert oscillations. An optical disk has a construction in which at least a recording layer is formed on the optical disk substrate.
摘要:
An optical disk has address recording sections each of which has a wobbled part of one of side walls of a groove. Each address recording section is formed by providing convexes of a groove in an adjacent land so as to widen the groove. With the wobbles thus provided in a concavo-convex form, address information is recorded. Besides, the address recording sections thus provided in the grooves are linearly disposed in radial directions of the optical disk. By thus arranging the optical disk on whose grooves and/or lands information is recorded, mixing of wobble frequency components in reproduced information signals does not occur, the sector method is applicable to the optical disk, and information signals of high quality can be obtained.
摘要:
An optical disk has address recording sections each of which has a wobbled part of one of side walls of a groove. Each address recording section is formed by providing convexes of a groove in an adjacent land so as to widen the groove. With the wobbles thus provided in a concavo-convex form, address information is recorded. Besides, the address recording sections thus provided in the grooves are linearly disposed in radial directions of the optical disk. By thus arranging the optical disk on whose grooves and/or lands information is recorded, mixing of wobble frequency components in reproduced information signals does not occur, the sector method is applicable to the optical disk, and information signals of high quality can be obtained.
摘要:
In an optical disk, grooves and lands serving as recording tracks are provided, the grooves are shaped so as to have virtually the same width, and in a first region, the two side walls of each groove wind in accordance with address information. The first region of the groove is formed with its leading portion located at the same angular position as the leading portion of at least one of the first regions of the adjacent grooves. Moreover, the winding portions corresponding to respective bits of the address information are formed in a manner so as to synchronize to the adjacent grooves. With this arrangement, it becomes possible to easily detect address information from the grooves and lands, and consequently to obtain an information reproducing signal with high quality.
摘要:
In a method for reproducing an optical disk of the present invention, address information of an optical disk, provided with tracking guides composed of (1) a wobbling groove wobbled in accordance with address information and (2) a normal groove which is not wobbled, is reproduced. The wobbling groove and the normal groove are alternately provided in a radius direction of the optical disk. When carrying out recording and reproducing of the optical disk, three beams composed of one main beam and two sub beams are used. The three beams are projected so that (a) the sub beams are respectively on the wobbling groove and the normal groove and (b) the main beam is on a land between the wobbling groove and the normal groove. The address information is found from reflected light of one of the sub beams. The above arrangement allows respective central portions of the sub beams to track the tracking guides. Therefore, even in the case where the optical disk is tilted or vibrated, the sub beams do not deviate totally off the tracking guides, thereby permitting to stably reproduce the address information.