摘要:
A substrate for manufacturing an optical memory device includes one surface covered with a protective film provided with openings only in portions corresponding to recording layers to be formed on the substrate, thereby allowing the protective film to function as a mask for forming the recording layers in a recording layer forming process. Also disclosed is a method of manufacturing an optical memory device including the steps of continuously feeding a substrate covered with a protective film provided with openings only in portions corresponding to recording layers to be formed on the substrate, forming the recording layers through the openings on the substrate, forming guide tracks on the substrate, stripping the protective film from the substrate, cutting the substrate to a predetermined size, and forming a protective layer on the substrate.
摘要:
A magneto-optical recording medium is consisted of a recording layer, a readout layer and a writing layer. The readout layer is made of rare earth-transition metal alloys wherein an easy magnetization axis is parallel to the recording layer at room temperature, and the easy magnetization axis is perpendicular to the recording layer as the temperature of the readout layer is raised above a predetermined temperature by irradiating thereon with a light beam. The writing layer is made of rare earth-transition metal alloys having such coercive force that a magnetization direction thereof is switched by an external magnetic field at room temperature and Curie temperature that is above Curie temperature of the recording layer. With the above arrangement, an overwriting function can be achieved by adjusting a light intensity of the light beam so that the temperature falls within the range between the Curie temperature of the writing layer and the Curie temperature of the recording layer, or above the Curie temperature of the writing layer.
摘要:
An optical tape including an optical recording layer for permitting information to be optically recorded thereon and a light-reflective magnetic layer; the light-reflective magnetic layer which reflects light projected onto the recording layer, also permits magnetic recording or magneto-optical recording to be performed thereon, thereby increasing a storage capacity of the optical tape remarkably; further, the optical tape is provided with a layer to form guiding grooves for tracking control, which layer to form guiding grooves is made up of ultraviolet-hardening resin, photo-resist, or a photochromic material.
摘要:
The magneto-optical recording medium is provided with a readout layer which shows the in-plane magnetization and which changes from the in-plane magnetization to the vertical magnetization when its temperature rises higher than a predetermined temperature by irradiation of the light beam, a memory layer which records information thereon magneto-optically, an intermediate layer which keeps in-plane magnetization from room temperatures to its Curie temperature, and an writing layer which has a Curie temperature higher than that of the memory layer and has coercive force lower than that of the memory layer. Since the intermediate layer becomes a domain wall in optical modulation recording, it prevents the memory layer and the writing layer from forming a domain wall, so information can be recorded in good condition. Moreover, a portion of the readout layer besides a center portion of the light beam shows the in-plane magnetization and masks the memory layer at playback. Therefore, a recording bit can be made small and recording density can be improved without increasing interference of signals from neighboring recording bits, which causes noises.
摘要:
A magneto-optical disk comprising a substrate whereon a recording medium is formed, and a depression is formed on the substrate on the inside of the recording medium of the substrate. A center hub is installed on the depression such that the center hub is substantially level with a protective resin layer covering the recording medium. On the center hub, a flying head performs CSS (Contact Start and Stop). This configuration of the disk eliminates the occurrence of dust due to the abrasion and head crash, and achieves stable CSS. A method of manufacturing the magneto-optical disk, wherein the protective resin layer is formed after installing the center hub on the depression. In this method, since a space is not produced between the center hub and the protective resin layer, the stable flying characteristics is obtained. And a magneto-optical disk whereon small physical bumps and pits are formed on the substrate on the inside of the recording medium, which prevents the flying head from sticking to the disk. A method of manufacturing the magneto-optical disk by using a stamper, which permits the disk to be mass produced.
摘要:
An optical tape including an optical recording layer for permitting information to be optically recorded thereon and a light-reflective magnetic layer. The light-reflective magnetic layer which reflects light projected onto the recording layer, also permits magnetic recording or magneto-optical recording to be performed thereon, thereby increasing a storage capacity of the optical tape remarkably. Further, the optical tape is provided with a layer to form guiding grooves for tracking control. The layer to form guiding grooves is made up of ultraviolet-hardening resin, photo-resist, or a photochromic material. For example, in the case of using ultraviolet-hardening resin, after a guiding groove pattern has been exposed by projecting an ultraviolet ray on a layer made up of ultraviolet-hardening resin, the exposed areas harden to form areas corresponding to guiding grooves between those exposed areas. The guiding grooves are formed by removing the areas corresponding to guiding grooves from the layer made up of the ultraviolet-hardening resin. Additionally, along with a guiding groove pattern, an index pattern can also be exposed. The guiding grooves thus formed do not reduce the recording density for information of the optical tape.
摘要:
A magneto-optical recording medium has a recording layer whereon information is magneto-optically recorded. A readout layer is provided on the recording layer. The readout layer has a compensating temperature that is located between room temperature and the Curie temperature. In the readout layer, upon an application of a light beam, the in-plane magnetization occurs at room temperature and a transition from the in-plane magnetization to vertical magnetization occurs as the temperature of the irradiated area of the readout layer rises above a predetermined temperature. By employing this magneto-optical recording medium, with an application of a light beam that is intensity modulated into two levels, only a spot having a temperature not less than a predetermined temperature is involved in the reproduction; therefore, a recorded bit with a size smaller than the diameter of the light beam can be reproduced, thereby greatly increasing the recording density. Further, the level of the reproduced signals is increased, and crosstalk from the adjoining tracks is reduced; thus, information recording and overwriting can be conducted more easily.
摘要:
A magneto-optical recording medium includes a first magnetic layer, a second magnetic layer and a third magnetic layer respectively made of rare earth-transition metal alloys. The first magnetic layer has a perpendicular magnetization in a temperature range between room temperature and its Curie temperature. The second magnetic layer has its Curie temperature higher than that of the first magnetic layer, and coercive force thereof at room temperature is nearly zero. The third magnetic layer has a perpendicular magnetization in a temperature range between room temperature and its Curie temperature. The Curie temperature of the third magnetic layer is higher than the Curie temperature of the first magnetic layer. The coercive force of the third magnetic layer at room temperature is lower than that of the first magnetic layer. The compensation temperature of the third magnetic layer is higher than that of the second magnetic layer. Having the above arrangement, an overwriting is permitted on the magneto-optical recording medium, and an initializing magnetic field and a recording magnetic field in a magneto-optical recording and reproducing device are set in the same direction.
摘要:
A magneto-optical recording medium has a recording layer including two magnetic layers. The magneto-optical recording medium satisfies a condition of .vertline.A.sub.1.K.sub.1 -A.sub.2.K.sub.2 .vertline..ltoreq.0.18 (erg.sup.2 /cm.sup.4) wherein A.sub.1, K.sub.1, A.sub.2, and K.sub.2 respectively represent an exchange constant of a first magnetic layer, a perpendicular magnetic anisotropy of the first magnetic layer, an exchange constant of a second magnetic layer, and a perpendicular magnetic anisotropy of the second magnetic layer. First and Second magnetic layers are made of TbFeCo.
摘要:
A magneto-optical recording medium comprising a readout layer, an intermediate layer, and a recording layer. Two light beams having high and low light intensities respectively are applied while applying an external magnetic field. The magnetization direction of the recording layer is changed according to information, by reversing the sub-lattice magnetic moment of the readout layer in the case of the high light intensity. The intermediate layer exhibits a perpendicular magnetization during the irradiation, and also exhibits an in-plane magnetization at room temperature. Since it is not necessary to provide a device for generating a magnetic field for initializing every recording, it is possible to avoid increase in the size of the recording and reproducing apparatus. Moreover, the magnetization direction of the readout layer can be easily controlled with an external magnetic field, and the optical modulation overwriting property can be stabilized.