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 recording medium comprising a readout layer and a recording layer has a relationship that an external magnetic field H1 is smaller than an external magnetic field H4, where the H1 is a minimum external magnetic field necessary to make a magnetization direction of the readout layer direct to the direction reverse to a magnetization direction of the recording layer substantially at the room temperature, and the H4 is a maximum external magnetic field necessary to make the magnetization direction of the readout layer direct to the direction same as the magnetization direction of the recording layer at an high temperature not lower than a predetermined temperature. Moreover, the magneto-optical disk is provided, between the readout layer and the recording layer, with an intermediate layer which inhibits an effective bias magnetic field from the recording layer to the readout layer at the room temperature. Since it is possible to reproduce only the information in the high-temperature area close to the center of the laser beam irradiated during reproducing, recording density is improved. Furthermore, since an initializing magnetic field at reproducing is not necessary and the reproducing magnetic field can be made smaller, the apparatus can be made smaller and the electric power consumption can be decreased.
摘要:
The method of the present invention is for recording, reproducing, and deleting information on and from an optical disk including a plurality of tracks each having M guide grooves (M is an integer equal to or larger than 2) and M-1 land(s) interposed between the adjacent guide grooves, at least one of the land(s) having a group of pits for producing address information. The method includes the step of: focusing light beams on the respective guide grooves and land(s) for effecting the recording, reproduction, and deletion of information. Such an optical disk is also provided.
摘要:
An optical recording element comprising a recording medium which includes an information recording area formed at every unit in a non-continuous condition, the recording medium further including sample pits disposed at intervals of a fixed distance for providing basic information about the locations of the recording units in same track. Each sample pit comprises a plurality of pits disposed next to the sequence of the recording units so that the spacing between the pits differs from the spacing between the recording units. At least one of the plurality of pits is a long-sized inclined pit which is inclined at an angle in the range of 6.degree. to 80.degree. to a recording track. A driving system for driving the optical recording element for recording information in the non-continuous recording area or erasing information stored therein with a light beam the output of which is varied as required and checking whether said recording or erasing has been correctly performed, within a very short time in which the light beam passes through the non-continuous recording area. By using the optical recording element in combination with its driving system, the processing speed for reducing, erasing and verifying these functions can be greatly improved and the irradiating position of the light beam at every recording unit can be correctly controlled.
摘要:
A surface of a magneto-optical recording medium of the present invention is textured with fine and physical protrusions and recessions. The shapes of physical protrusions and recessions vary at each radial locations on the medium such that, for example, rough protrusions and recessions are formed in inner parts of the recording medium and fine protrusions and recessions are formed in outer parts thereof. Therefore, floating force given to a floating head from the medium being rotated based on the constant angular velocity method through an air layer in the outer parts equals floating force in the inner parts. Consequently, since the floating height of the floating head becomes constant irrespective of radial locations on the medium, information can be recorded under constant recording conditions, permitting the accuracy of the recording to improve. Regarding a method for processing the surface of a magneto-optical recording medium relating to the present invention, for example, a texture tape whose roughness is large is used in inner parts of the medium while a texture tape whose roughness is small is used in outer parts thereof. As a result, a magneto-optical recording medium having the above characteristics is produced.
摘要:
A magneto-optical memory element including: grooves, formed on at least one surface of a transparent substrate, for guiding a light beam; a magneto-optical recording layer formed on the surface of said transparent substrate on which the grooves are formed, wherein a width of each groove and a width of each land formed between the grooves are substantially equal, information is recorded on and reproduced from tracks on the grooves and the lands, and a groove depth d (track depth) is arranged such that 0.13.times..lambda./n.ltoreq.d.ltoreq. 0.18.times. .lambda./n, where .lambda. is a wavelength of the light beam and n is a refraction index of the transparent substrate. Assuming that a diameter of the light beam at a portion where a light intensity of the light beam becomes 1/e.sup.2 of a light intensity of the center of the light beam is L, a track pitch p is arranged such that 0.6.ltoreq.L/p.ltoreq.1.2. Therefore, even when the track density is increased, i.e., the width of the groove portion and the width of the land portion are reduced, a satisfactory signal quality with low level of crosstalk is obtained. Accordingly, such a magneto-optical disk achieves a high recording density.
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 external magnetic field device for a magnetooptical information recording and reproducing apparatus in which an external magnetic field to be applied to a magnetooptical information recording medium is modulated by supplying to a magnetic head an alternate current the polarity of which is changed according to information to be recorded. The device comprises an offset circuit for producing an offset in the alternate current. The direction of the offset is selected so as to increase the current level of the polarity by which the initial magnetization of the information recording medium is reversed. The direction of the offset may be selected so as to cancel the leakage magnetic field.
摘要:
An optical memory device comprising at least one transparent substrate and a light reflection layer or an optical memory layer laminated on one surface of the substrate, in which the light reflection layer or the optical memory layer is constituted with a UV-ray or electron-ray cured resin dispersingly containing a light reflective metal powder or an optical recording material.
摘要:
A magnetic disk device having a floating-type magnetic head, for use with a disk-shaped recording medium having a sliding area for the floating-type magnetic head formed outside a recording area. The length in the disk radial direction of a suspension supporting the floating-type magnetic head is varied depending on individual magnetic disk devices. In another arrangement, a control means is provided for setting two reference values so that a radial position of the floating-type magnetic head detected by a detection section is compared with these reference values, and for alternating one of the preset reference values to the other reference value upon receiving a rotation stop signal. In still another arrangement, control means is provided, whereby a radial position for sliding of the floating-type magnetic head is randomly varied within the sliding area. According to these arrangements, since the radial position for sliding of the floating-type magnetic head is varied within the sliding area without being located at the same position, abrasion within the sliding area can be dispersed. As a result, it becomes possible to extend the longevities of the floating-type magnetic head and the recording medium.