摘要:
A magneto-optical memory element has a multi-layer construction in the order from a side first receiving light from a light-source which includes a first transparent dielectric film, a rare earth transition metal alloy film, a second transparent dielectric film and a reflective film. The magneto-optical device uses circular dichroism effect of a magnetic mater for reading information. The rare earth transition metal alloy film has a refractive index represented by n.+-..DELTA.n wherein n=3.2-3.55i and .DELTA.n=0.05-0.03i. The thickness of film is about 18 to 46 nm. The second transparent dielectric film has a refractive index of 2.0.+-.0.2 and a film thickness of 80 to 108 nm.
摘要:
An optical memory device comprising:a transparent substrate; anda recording film deposited on the transparent substrate, the recording film being formed by preparing a composition in which a diarylethene-type photochromic compound is dispersed in an ultraviolet-curing polyurethaneacrylate resin of solventless type and by curing the composition by an ultraviolet ray irradiation.
摘要:
A magneto-optic memory device, such as a magneto-optic disk or magneto-optic card having a pair of opposed substrates at least one of which is transparent. Between the substrates is a magneto-optic memory layer made of a stack of dielectric film, a rear earth-transition metal alloy thin film, a dielectric film and a light reflecting film built on the surface of the transparent substrate opposed to the other substrate. An adhesive layer covers the memory layer and bonds the transparent substrate to the other substrate. Lastly, a metal nitride film interposed between the light reflecting film of the memory layer and the adhesive layer.
摘要:
A magneto-optical head wherein a light flux, which is reflected from a recording medium, is separated into its central portion and remaining portion. The central light flux portion is only used as a magneto-optical signal while the remaining light flux portion is only used as an optical servo signal.
摘要:
An optical head for a magneto-optical disk, including a diaphragm for cutting at least an outer portion of a bundle of rays, which is provided in the course of an optical system of a signal detecting portion.
摘要:
Featured is a recording and reproducing method of a magneto-optical recording medium including a recording layer for recording thereon information magneto-optically and a readout layer which has in-plane magnetization at room temperature and where a transition occurs from in-plane magnetization to perpendicular magnetization as temperature raises. The method includes projecting a light beam onto such a magneto-optical recording medium so as to form a perpendicularly magnetized area in the readout layer by duplication of the magnetization of said recording layer to the area. In further embodiments, the recording medium further includes an intermediate layer made of non-magnetic film formed between the readout and recording layers and the readout and recording layers are composed of rare-earth transition metal alloys such as TbFeCo (recoding layer) readout layer, made of GdFeCo (readout layer).
摘要:
Featured is a recording and reproducing method for recording and reproducing information on and from a recording medium. The medium includes a base having a property that a light can be transmitted therethrough, a readout layer formed on the base, which has an in-plane magnetization at room temperature, whereas, a transition occurs from in-plane magnetization to perpendicular magnetization as temperature rises and a recording layer formed on said readout layer for recording thereon information magneto-optically. A groove for guiding a light beam is formed on a readout layer side of the base and a groove width is set substantially equal to a land width formed between grooves. The recording layer on the grooves and the recording layer on lands are used in recording and reproducing information. Further a light beam is incident on a converging lens of an optical head, the light beam having a larger diameter &ohgr; than an aperture &agr; of the converging lens for converging the light beam on a predetermined position of the magneto-optical recording medium.
摘要:
A magnetic recording medium having a recording layer made up of a ferrimagnetic material whose compensation temperature is included within room temperatures and an information recording-reproduction method using the magnetic recording medium. During recording, while a light beam is projected on the recording layer so as to raise the temperature of a recording portion, information is recorded by applying a signal magnetic field from a magnetic head. During reproduction, while a light beam is projected on a reproducing portion of the recording layer so as to raise the temperature thereof, information is reproduced by detecting leakage flux from the reproducing portion by the magnetic head. Thus, during reproduction, no magnetic flux is generated from other portions of the recording layer not irradiated by the light beam. With the arrangement, crosstalk due to leakage flux from adjoining tracks not irradiated by the optical beam can be eliminated. Therefore, track pitches can be made narrower so as to increase recording density of the magnetic recording medium. Further, since crosstalk from adjoining tracks is eliminated, a high S/N can be achieved.
摘要:
A magneto-optical disk, which possesses a disc-shaped substrate and a recording layer composed of a perpendicular magnetization film that is formed on the substrate, characterized in having: an area wherein magnetic domains having an upward magnetization and magnetic domains having a downward magnetization are alternately aligned along at least one circuit of the disk, the area being formed on the recording layer, the length of the magnetic domains having the upward magnetization being virtually equal to the length of the magnetic domains having the downward magnetization. This invention also has a reproducing method which is characterized in that, when information is reproduced by projecting a light beam onto the magneto-optical recording disk, the intensity of the light beam is adjusted so as to maximize the amplitude of a reproduced signal that is obtained from the area. With the above arrangement, a high-quality reproduced signal can be obtained independent of the characteristics of individual magneto-optical disks.
摘要:
A magneto-optical recording and reproducing device is provided with a magneto-optical disk for reproducing recorded information using light, a semiconductor laser, an objective lens for converging a light beam emitted from the semiconductor laser onto the magneto-optical disk and a light interrupting member for interrupting a portion of a light beam before it is incident on the objective lens. The magneto-optical disk is composed of a readout layer which is predominant in in-plane magnetization, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised and a recording layer for recording thereon information using a perpendicular magnetization. In this arrangement, since the light interrupting member is provided, a light spot can be made smaller, thereby improving a recording density. Moreover, even when temperature of the readout layer is raised due to a side robe generated by the light interrupting member, in-plane magnetization is maintained in the readout layer. Thus, interference by unwanted reproducing signals due to the side robe can be prevented, thereby improving a reproducing signal quality.