Abstract: A low-laser-noise semiconductor driver device is provided for use in an optical information processing device which is recordable or erasable and which oscillates a semiconductor laser with a high output when it is recorded or erased. A semiconductor is generally oscillated with a rated maximum output during a recording and erasing operation. Therefore, when high frequency superposition is made in such a high output oscillation state, an oscillation output exceeds the rated output, which badly influences the life of the laser. To obviate this drawback, the high frequency superposition is stopped at the mode of recording or erasing in which the high output oscillation is made by a switching circuit which is controlled by a mode control signal. This reduces the laser noise at the mode of reproducing and also lengthens the life of the semiconductor laser.

Abstract: An electron beam memory system in which a phase transition type recording film is used as an information recording medium, and for recording information, a focused electron beam is selectively projected on desired positions of the recording film so as to locally heat the recording film and cause phase transition, while for retrieving information, an electron beam having energy at a degree not causing the phase transition is projected so as to utilize the fact that reflection or diffraction of the primary electron beam projected at the retrieval differs between the recorded regions and unrecorded regions.

Abstract: An optical information processing apparatus uses an optical disk having correction marks such as mirror surfaces or wobbled pits intermittently arranged along a guide track. In a reproduce mode, tracking control is effected by correcting a tracking signal by a tracking offset component detected by the correction marks. In a record or erase mode, the track offset correction is deactivated and record or erase operation is controlled in accordance with an output level of the detected track offset component so that incomplete eraser of recorded data is prevented.

Abstract: In an information recording apparatus according to this invention, since it is not necessary to dispose any differential circuit, which was required heretofore, it is possible to fabricate it with a low cost and its error rate is also very small.Furthermore, since the mean reflectivity on the recording track does almost not vary by the fact that information is recorded there, no tracking off-set or focusing off-set is produced. Thus effects of this invention are remarkable.

Abstract: In case of rewriting data by means of an erasable optical disc memory recording new data after having erased a series of data already stored, directory data written in an optical disc memory in order to control the written data are transferred to an external directory memory and write-in and read-out are controlled by using the directory memory. For rewriting data, which have been already recorded and which are recorded under a specified file name, the data are not erased and renewed data are written in another recording region, where recording is possible. The data, which have become unnecessary as the result of renewal, are erased during a period of time, when the optical disc memory is not accessed.

Abstract: In a data recording member having a data recording film which is formed on a substrate either directly or via at least one of inorganic and organic protective layers and which causes the change of atomic arrangement upon being irradiated by recording beam, the improvement wherein said data recording film has an average composition in a direction of the film thickness expressed by the following formulas:M.sub.x Te.sub.y Se.sub.z O.sub..alpha.wherein x, y, z and .alpha. are values within the ranges of 2.ltoreq.x.ltoreq.40, 30.ltoreq.y.ltoreq.95, 3.ltoreq.z.ltoreq.45, 0.ltoreq..alpha..ltoreq.20, and M is at least one element selected from the group consisting of As, Sb, Bi, S, Si, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Au, Ag, Cu, Ni, Pd, Rh, Cr, Mo, W and Ta.

Abstract: A tracking servo system using an optical disc with guide grooves formed thereon for a plurality of tracks each having a plurality of interrupting portions, wherein a tracking signal is detected from the diffracted light of a beam spot irradiated to the optical disc and reflected from the guide groove, then the tracking signal is corrected by a signal component included therein and obtained from the interrupting portions, and the track is traced by the use of such corrected signal and the tracking signal.

Abstract: Method and apparatus for optically detecting information from a recording medium in which pits are formed by thermal energy of a light spot to record the information. A reproduction spot is irradiated onto the recording medium to produce a detection signal. From a differential signal of the detection signal, a signal indicative of zero points of the differential signal and a signal indicative of the presence of the pits are detected, and both the signals are used to detect positions of the pits. For stable and accurate detection of the pit position, the relation between pit size W and reproduction spot size W.sub.s is prescribed and the pit size and reproduction spot size are so set as to satisfy 0.45.ltoreq.W/W.sub.s .ltoreq.0.75.

Abstract: An information recording disc is provided with a magnetic attracting member in the form of metal piece or magnetic material which serves for attracting a disc member for recording, in particular, for optical recording and reproducing of information, to a spindle of a recording and reproducing apparatus. The magnetic attracting member is held in the space of a holder which is fixedly secured to the disc without the magnetic attracting member being fixedly secured to the disc. This arrangement enables a magnetic clamping of the disc member which provides for a decrease of retardation and is suitable for miniaturization of the apparatus.

Abstract: This invention relates to a track setting method for a tracking servo system in an optical disk device and a device therefor. According to this invention the track passage velocity when the light spot moves across the track is detected and setting of the light spot onto the track is performed under the condition that the passage velocity thus detected is lower than a predetermined velocity. In the case where the passage velocity is greater than the predetermined velocity, the light spot is forced to move so that the passage velocity is lower than the predetermined velocity and the light spot is set up thereafter.

Abstract: In an optical information recording and reproducing apparatus having a laser light source and an optical system so that a beam from the laser light source is irradiated through the optical system on an information recording medium to record and reproduce information, an accousto-optic modulator is disposed in the optical system for receiving the beam from the laser light source, and a modulation unit is provided which comprises an oscillator for generating a plurality of signals at different frequencies, a modulator for modulating the outputs of the oscillator and an adder for adding together the outputs of the modulator.

Abstract: In an optical recording system wherein the intensity of a laser beam is modulated with an input modulation signal so as to record information on a recording medium, the intensity modulation of the laser beam is performed after the pulse waveform of the input modulation signal is converted into two pulses which express the front edge and rear edge of the pulse waveform respectively.

Abstract: In a data recording member having a data recording film which is formed on a substrate either directly or via at least one of inorganic and organic protective layers and which causes the change of atomic arrangement upon being irradiated by recording beam, the improvement wherein said data recording film has an average composition in a direction of the film thickness expressed by the following formulas:M.sub.x Te.sub.y Se.sub.z O.sub..alpha.wherein x, y, z and .alpha. are values within the ranges of 2.ltoreq.x.ltoreq.40, 30.ltoreq.y.ltoreq.95, 3.ltoreq.z.ltoreq.45, 0.ltoreq..alpha..ltoreq.20, and M is at least one element selected from the group consisting of As, Sb, Bi, S, Si, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Au, Ag, Cu, Ni, Pd, Rh, Cr, Mo, W and Ta.

Abstract: A method of detecting a light spot control signal is disclosed in which, when information is reproduced from an optical disk for optically recording information, a signal level obtained at a high-reflectivity portion of the optical disk is taken out of a signal reproduced from the optical disk, and is used as a control signal, which controls a light spot so that it tracks information stored in the optical disk.

Abstract: In an information recording apparatus for recording predetermined information on a recording medium by means of a laser beam, an optical system and a light detector are arranged for detecting a reflected version of the laser beam from the recording medium, whereby the focusing of the laser beam on the recording medium is automatically controlled.

Abstract: In an optical information processor such as an optical disc apparatus, when a light beam is irradiated to a plurality of tracks on an information recording medium, the plurality of tracks act as a diffraction grating. Areas in which light receiving parts of a light detector are arranged are determined by a track pitch, a wavelength and a numerical aperture of a condenser lens so that the light detector detects only a change in a light intensity due to an interference between a 0-order diffracted light ray and a 1-order diffracted light ray.

Abstract: An information recording member comprising a substrate, and a thin film formed on the substrate with or without an intermediate layer therebetween and irradiated with a recording beam to make an aperture or recess in the thin film, is disclosed in which the thin film is a crystalline film and has a composition expressed by a general formula Se.sub.x Te.sub.y M.sub.z, where x, y and z are given by formulae 0.02.ltoreq.x.ltoreq. 0.35, 0.50.ltoreq.y.ltoreq.0.98 and 0.ltoreq.z.ltoreq.0.45, respectively, and M indicates at least one element selected from the group consisting of As, Sb, Bi, S, Si, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Au, Ag, Cu, Ni, Pd, Rh, Cr, Mo, W and Ta, and in which the thin film does not deteriorate to such an extent as seen in conventional recording films when a time has elasped, since the thin film is crystalline.

Abstract: A substrate of a recording member comprising a hard base, a first organic substance layer which is formed on the base, and a second organic substance layer which is made of a solvent-soluble organic substance and which is formed on a surface of the first organic substance layer opposite to a surface thereof lying in contact with the base. This substrate can be reused.

Abstract: An optical disk for accumulating information in the form in which an information signal can be optically read, wherein to the end of additionally recording information, a line of pits are arrayed at periodical intervals on an information recording carrier and are recorded in a manner to minutely wobble in the rotating direction of the disk at a fixed period.

Abstract: A recording medium having at least a first inorganic material layer which overlies a predetermined substrate and which exhibits a light absorptivity for projected light, and a recording layer which overlies the first inorganic material layer and whose principal component is an organic material. The first inorganic material layer contains at least one element selected from the group consisting of In, Bi, Te, Sb, Ge, Sn, Pb, Cr, Nb, Ni, Pd, Fe, Pt, Re, Ta, Th, Ti, Zr and Tl and the content of the element or elements is at least 65 atomic-%.Further, the first inorganic material layer may well be overlaid with a second inorganic material layer which exhibits a light transmissivity higher than that of this first inorganic material layer. Preferable as the material of the second inorganic material layer is an inorganic material which contains at least one element selected from the group consisting of In, Bi, Te, Sb, Pb, Ge and Sn and at least one element selected from the group consisting of S, Se and O.