Abstract: An information recording apparatus for injecting an energy beam into a recording medium to form locally a region different in physical properties from a non-recording region to thereby record information, has a drive for driving an energy generation source for changing the number of injected energy pulses in a mark forming period in accordance with the mark length so that the interval between arbitrary two points of the change of injected power level at the time of information recording is substantially set to be longer than a half of a detection window width in order to make it easy to drive a recording energy generation source to thereby form said mark accurately and speedily and, at the same time, in order to secure a sufficient time required for cooling the recording medium.

Abstract: An optical reproduction method for reproducing information includes intermittently irradiating light to a moving optical medium, detecting reflected light from the moving optical medium while the light is irradiated intermittently when a moving distance of a light spot of the intermittently irradiated light on the moving optical medium is smaller than a diameter of the light spot, processing information based on the detected reflected light utilizing a differential operation, and obtaining a reproduction signal based on the differential operation.

Abstract: A method for recording information is disclosed in which an information recording medium is irradiated with a recording energy beam power-modulated into at least a record power level and a record-ready power level lower than the record power level. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion. Also, only in the case where the energy beam is modulated by the power lower in power level than the record-ready power level after the last pulse of the energy beam pulse train including at least one pulse for forming a mark portion and the mark portion is followed by a space portion of a predetermined length, the particular radiation energy of low power level is reduced as compared with when the mark portion is followed by a space potion of a different length.

Abstract: An objective is to provide a technique capable of reproducing high-density recorded fine recording marks with excellent high output and excellent quality. To this end, with the present invention, light 501 is irradiated intermittently to an optical recording medium changeable in optical nature due to irradiation of light, permitting a differential amplifier 503 to perform differential processing of a signal as obtained by detection of reflection light rays at at least two time points during irradiation of the intermittent light to thereby obtain a reproduction signal. It is thus possible to effectively detect only a signal component of certain part whereat the reflection light is changed due to light irradiation during irradiation of the intermittent light, which in turn enables reproduction of fine record information with increased resolution while enabling suppression of those components other than the change component. This makes it possible to obtain a reproduction signal with good quality.

Abstract: An information recording apparatus capable of forming a fine mark reliably and highly precisely through compensation for thermal interference and heat accumulation. The information recording apparatus is provided with a recording energy irradiating unit for generating at least two recording waveforms when marks of the same length or spaces of the same length in a channel data sequence are recorded. The information recording apparatus constructed as above can realize highly reliable recording/reproducing operations and can be made compact at a low cost with a large storage capacity.

Abstract: A high-speed large capacity file system is built in which the track density is improved by applying a highly precise magnetic domain width control technique to a light pulse-irradiated magnetic field modulation magnetooptical disk device which can be overwritten and is suitable for the improvement of the bit density. For the purpose, bipolar magnetic domains having edges of positive and negative polarities with respect to the direction of movement of a light spot are formed and the recording condition is optimized. Normal recording is carried out on the basis of the result of the optimization of the recording condition.

Abstract: In order to eliminate noise of a solid state laser apparatus generating a blue light wave, the solid state laser apparatus comprises a solid state laser light source, an optical modulator having a light modulating function and outputting the modulated light therefrom as a desired light output, a photo-detector converting one part of output light from the solid state laser light source to an electrical signal, an electrical circuit detecting a noise component from the electrical signal and moving the phase of an electrical signal corresponding to the noise component, and a controller for applying the output signal of the electrical circuit to the optical modulator so as to substantially eliminate light of the blue light wave corresponding to the noise component so as to provide the desired light output from the optical modulator.

Abstract: An information recording apparatus capable of forming a fine mark reliably and highly precisely through compensation for thermal interference and heat accumulation. The information recording apparatus is provided with a recording energy irradiating unit for generating at least two recording waveforms when marks of the same length or spaces of the same length in a channel data sequence are recorded. The information recording apparatus constructed as above can realize highly reliable recording/reproducing operations and can be made compact at a low cost with a large storage capacity.

Abstract: An optical recording medium, optical recording method with use of it, and optical recording device for it comprise at least one magnetic layer on a substrate, the magnetic layer having a temperature Tco at which sizes of domains of the magnetic layer is sharply shrunk or expanded with temperature, thereby being capable of writing and reproducing high-density information formed of smaller domains than an optical spot diameter in a high signal quality.

Abstract: An optical recording/reproducing method employs a recording laser beam having a first output and a first wavelength, and a reproducing laser beam having a second output lower than the first output and a second wavelength shorter than the first wavelength. A disk-like recording medium is irradiated with the recording and reproducing laser beams by use of an objective lens having an NA of about 0.55 so that a small mark equal to or smaller than about one fourth of a spot size optically defined from the wavelength of the recording laser beam and the NA of the objective lens is formed on the recording medium by a recording characteristic of the recording medium and a shielding plate provided in an optical system for irradiation with the laser beam. Two-dimensional recording is performed as a recording system to arrange marks at lattice points of a two-dimensional lattice which extend in a track direction and a track radius direction.

Abstract: An optical recording medium, optical recording method with use of it, and optical recording device for it comprise at least one magnetic layer on a substrate, the magnetic layer having a temperature Tco at which sizes of domains of the magnetic layer is sharply shrunk or expanded with temperature, thereby being capable of writing and reproducing high-density information formed of smaller domains than an optical spot diameter in a high signal quality.

Abstract: An optical recording/reproducing method employs a recording laser beam having a first output and a first wavelength, and a reproducing laser beam having a second output lower than the first output and a second wavelength shorter than the first wavelength. A disk-like recording medium is irradiated with the recording and reproducing laser beams by use of an objective lens having an NA of about 0.55 so that a small mark equal to or smaller than about one fourth of a spot size optically defined from the wavelength of the recording laser beam and the NA of the objective lens is formed on the recording medium by a recording characteristic of the recording medium and a shielding plate provided in an optical system for irradiation with the laser beam. Two-dimensional recording is performed as a recording system to arrange marks at lattice points of a two-dimensional lattice which extend in a track direction and a track radius direction.

Abstract: An optical disk apparatus is capable of recording, reproduction and erasure by a laser beam. The user data is recorded in a RAM area on an optical disk by a recording device including a modulation encoder and a recording waveform generator. At the time of reproduction, the data in the RAM/ROM area is detected by a reproduction device to thereby demodulate the user data.