摘要:
A record medium according to the present invention includes a substrate having concave or convex information pits and a thermosensitive material film formed on the substrate. The thermosensitive material film is changed from a high reflectance state to a low reflectance state when its temperature becomes a high level and returns to the high reflectance state when its temperature decreases to a low level. In the case where information is reproduced, when a light beam having a predetermined power is irradiated to the record medium, heat generated by the light beam is confined in the pits and the temperature in the pits increases; the thermosensitive material on the pits becomes the low reflectance state. The flat portions between the pits has high heat radiation and thus, the temperature in the flat portions does not increase so much; therefore, the state of the thermosensitive material film on the flat portions is not changed. Thus, an optical power of reflected light from the pits to which a light beam is irradiated is decreased, so that an amplitude of a reproduced signal is increased.
摘要:
A multivalued information recording method in which energy applied to information units on a recording medium is varied to record multivalued information. In accordance with a relationship between the multivalued information in a predetermined information unit and the multivalued information in information units adjacent to the predetermined information unit, the energy applied to the predetermined information unit is decided.
摘要:
On a substrate, a recording layer which reversibly transforms between two states with different optical properties--a crystalline phase and an amorphous phase--by the irradiation of a laser beam, a first and a second dielectric layer on the bottom and the top surfaces of the recording layer, and a third dielectric layer on one surface of the first or the second dielectric layers and on the opposite side with respect to the recording layer are successively laminated, thus preparing an optical information recording medium. The third dielectric layer has a smaller coefficient of thermal expansion than the first and the second dielectric layers, so that the thermal deformation of the first and the second dielectric layers is reduced and the mass transfer of the recording layer is controlled. As a result, the overwrite cycle characteristics of the optical information recording medium are excellent.
摘要:
The optical density and/or the reflectivity of a recording layer included in an optical disk is selectively changed to record information by irradiation with a semiconductor laser beam, while the recording layer may be covered with a suitable protective film. The thickness of the recording layer is so determined that it is able to record information by means of a continuous wave type semiconductor laser beam, while the optical absorption rate of the recording layer is adjusted by setting the percentages of particular additives. The recorded information may be reproduced by the application of a laser beam, the incident power of which is lower than that of the recording beam, to detect the reflected light.
摘要:
An optical information recording material comprising a thin film of a suboxide of a metal or semimetal of Group IIIB, IVB, VB or VIB, e.g. TeO.sub.x where x
摘要:
An optical information recording medium is provided in which the active layer is a phase change material capable of absorbing energy and being converted between a substantially amorphous state and a substantially crystalline state. The active layer contains nitrogen, which may be in the form of a nitride or nitrides of the constituent elements of the active layer, or may be a nitrided surface thereof. The inclusion of nitrogen inhibits localized shifting of the active material, which leads to degradation of the recording/erase properties of the medium. The optical recording medium includes a substrate, onto which is deposited in sequence a first dielectric layer, a nitrogen-containing active layer, a second dielectric layer, and a metallic reflecting layer. The second dielectric layer is made thin, so that the cooling rate of the active layer is increased to form a more uniform amorphous state.
摘要:
A phase change type information storage disk in which a reflective layer is formed of an alloy thin film comprising as a main component any one of Ni--Cr, Cr or Ti and a metal having a larger malleability than said main component, being easy to be initialized and strong to thermal shock.
摘要:
An optical information recording medium is provided in which the active layer is a phase change material capable of absorbing energy and being converted between a substantially amorphous state and a substantially crystalline state. The active layer contains nitrogen, which may be in the form of a nitride or nitrides of the constituent elements of the active layer, or may be a nitrided surface thereof. The inclusion of nitrogen inhibits localized shifting of the active material, which leads to degradation of the recording/erase properties of the medium. The optical recording medium includes a substrate, onto which is deposited in sequence a first dielectric layer, a nitrogen-containing active layer, a second dielectric layer, and a metallic reflecting layer. The second dielectric layer is made thin, so that the cooling rate of the active layer is increased to form a more uniform amorphous state.
摘要:
An optical information recording and reproducing disc information has a substrate in the surface of which are formed signal recording grooves and cue signal recording pits. A light-absorbing thin film is formed on the surface of the substrate, the optical characteristics of the light-absorbing film being changeable thermally through irradiation by a light beam. The pitches of the grooves and pits, as well as the widths of the grooves and pits, are determined to meet specific conditions in relation to the diameter of the laser beam which is used for recording and reproduction of the signals. In addition, the depths of the grooves and pits are determined suitably in relation to the wavelength of the laser beam. With this arrangement, it is possible to attain a high quality of reproduction of information from the disc.
摘要:
A system and a method of recording information by changes of refractive index and light absorption coefficient on a thin film, and reproducing the recorded information byscanning a focussed monochromatic light along a track on a thin film of a selected thickness andletting a light component reflected at a light-incident surface of said thin film and the other light component reflected at an inside face of the opposite surface to said incident surface of the thin film interfere with each other thereby efficiently to vary intensity of reflection light.