Abstract: Provided is a thin film single pole head for perpendicular magnetic recording, which has a structure offering a high formatted volume, easy servo, difficulty of influencing a recording pattern on a medium, and capability of shortening processing time. This thin film single pole head for perpendicular magnetic recording is formed on a reproducing head composed of a pair of shield layers formed on a substrate, and a reproducing element formed therebetween. A structure is provided, where an auxiliary pole is not disposed between the reproducing element of the reproducing head and the main pole of a recording head when seen from a surface facing to recording media.

Abstract: Multibeam optical disk record and reproduction apparatus and method, in which at least two light beams generated are concentrated in different positions of on recording tracks of a recording medium to record or reproduce data to or from the recording medium on the different positions at the same time. The light beams are moved independently of each other across the recording tracks so that any one light beam is movable during the recording or reproducing of data by another light beam. This allows parallel recording/reproducing with a plurality of light beams without producing areas unaccessed due to the jumps of the light beams.

Abstract: The computer system includes a host system, a recording medium, and a digital signal decoder connected to the host system and the recording medium. The digital signal decoder receives M-bit data and generates an N-bit code word from the M-bit data. The number of consecutive bits of 1 in the code word is not larger than a first predetermined number K, and the number of consecutive bits of 0 is not larger than a second predetermined number L. When data is recorded/reproduced by a method such as NRZI (Non-Return to Zero Inverted), or the like, there is a defect in that the number of transitions of data is larger in a code with a high data encoding rate, and the run length of zero is long thereby increasing the data decoding error rate with the recording/reproducing of data. In the digital signal decoder according to the present invention, any code word includes at most 3 consecutive bits of 1, and at most 11 consecutive bits of 0, so that the data decoding error rate can be reduced.

Abstract: When the amount of position error PE of a magnetic head meets the condition of Ewf>PE>=Eww for two threshold values Ewf and Eww meeting Ewf>Eww, the track is registered in the track information table as a track requiring rewrite and the tracks on both sides neighboring to the track are temporarily write-inhibited. The data of the track is rewritten on another track later so as to maintain the data.

Abstract: An information storage apparatus has a disk medium setting data recording areas along a plurality of tracks concentrically arranged, a head for recording and reproducing data on tracks of the disk medium, an actuator for moving the head to a desired track among the plurality of tracks. Also included is an electric circuit for controlling recording and reproducing in response to detecting the distance from a recorded magnetization pattern on an adjacent track in the radial direction by detecting previously recorded signals on adjacent tracks while data recording. Even if the track density is increased, the upper limit of a threshold value of a function for preventing off-track recording of the information storage apparatus can be increased and a high track density of the information storage apparatus can be easily realized.

Abstract: In order to generate a sampling clock having a higher accuracy, a synchronous signal generating circuit is provided with a phase error detector, detecting a phase error of a read out signal digitized on the basis of FDTS algorithm, and a VCO, controlling an oscillation frequency on the basis of a phase error detected by the phase error detector, to generate a synchronous signal by the VCO. On the basis of the synchronous signal generated by the synchronous signal generating circuit, an ADC digitizes the read out signal. The digitized read out signal is then converted to binary data by a detection circuit.

Abstract: When the amount of position error PE of a magnetic head meets the condition of Ewf>PE>=Eww for two threshold values Ewf and Eww meeting Ewf>Eww, the track is registered in the track information table as a track requiring rewrite and the tracks on both sides neighboring to the track are temporarily write-inhibited. The data of the track is rewritten on another track later so as to maintain the data. By doing this, the offtrack of the recording track can be made smaller without sacrifice of the access speed and the occurrence probability of write fault can be reduced. Furthermore, the reliability of a magnetic disk apparatus can be improved.

Abstract: To provide improved acrylic resin which has weatherability such as the gloss-retaining ability almost as good as that of the fluorine resin or silicone resin while maintaining the advantages of the conventional acrylic resin binder as paint resin such as the gloss or pigment dispersion stability. The emulsion is characterized in that it comprises in 100 wt. % of resin emulsion component thereof: (a) 0.1 to 10 wt. % of a monomer containing light stabilizing group; and (b) 0.1 to 10 wt. % of a monomer containing alkoxysilyl group. Preferably, it further comprises (c) 0.1 to 10 wt. % of monomer containing ultra-violet absorbent group.

Abstract: A super high density optical disk apparatus is obtained by using an exchangeable recording medium having a recording capacity of at least 1.5 Gb/in.sup.2 in an optical recording and reading apparatus for recording or reading at least using a laser beam or by using one of means which can record on a recording medium only once and means which can record at least two times repeatedly as recording means to be used.

Abstract: In a write control method on an optical recording, at least one shift amount selected from the defocus amount of a laser beam on a recording medium, the shift amount of a recording position on a recording track and the shift amount of laser power during recording is controlled such that the selected amount falls within a predetermined range. Subsequently, a trial signal is trially recorded at a plurality of trial zones on the recording medium by using a laser power value as a parameter. The recorded trial signal is read and a difference .DELTA.V between center levels of a highest density waveform and a lowest density waveform is detected. In connection with each trial zone, the laser power value when a reading trial signal which makes the difference .DELTA.V minimum is recorded is defined as an optimum recording power value.

Abstract: In an information recording/reproducing apparatus constructed of: a buffer for storing therein consecutive recording data in a unit of two dimensional conversion; a coding device for converting the consecutive recording data into a two-dimensional data arrangement arranged by "n" lines and "m" columns corresponding to said unit of data; a recording device for subdividing said two-dimensional data arrangement arranged by "n" lines and "m" columns so as to be read out, and for controlling "m" pieces of light sources in accordance with these data series; and an optical apparatus for converging luminous fluxes from said "m" pieces of light sources so as to form "m" pieces of spots on a disk plane, the recording data is recorded on the disk plane as an optically distringuishable pit group having two-dimensionally extended areas arranged by "n" lines and "m" columns.

Abstract: An optical method for recording, reproducing, and erasing a digital signal of a mark length recording system onto/from an optical recording medium such as an optical disc or the like eliminates a fluctuation of the edge position of the reproduction signal due to heat interference between pits, thereby reducing a fluctuation of the edge position due to a fluctuation of external environmental conditions. For this purpose, there are proposed the following methods: 1) the shape of the recording pulse waveform is controlled, 2) the density at which data is recorded to the disc is variably set in accordance with the disc position, 3) a test recording is executed prior to recording user data, and the like. With these methods, a superhigh density optical recording can be realized.

Abstract: In a write control method on an optical recording, at least one shift amount selected from the defocus amount of a laser beam on a recording medium, the shift amount of a recording position on a recording track and the shift amount of laser power during recording is controlled such that the selected amount falls within a predetermined range. Subsequently, a trial signal is trially recorded at a plurality of trial zones on the recording medium by using a laser power value as a parameter. The recorded trial signal is read and a difference .DELTA.V between center levels of a highest density waveform and a lowest density waveform is detected. In connection with each trial zone, the laser power value when a reading trial signal which makes the difference .DELTA.V minimum is recorded is defined as an optimum recording power value.

Abstract: An optical recording medium on which information is recorded by irradiating the medium with a light spot to cause a characteristic change of an actual reflection factor, the optical recording medium including grooves of different optical depths which extend in a direction in which the light spot is moved relative to the medium and which are alternately and periodically formed in a direction perpendicular to the relative movement direction of the light spot so that a plurality of grooves thereof can be covered by the light spot, and mark recording regions provided on the flat surfaces between the grooves, the pitch of the flat surfaces between the grooves being selected to be substantially half the diameter of the light spot, thus increasing the recording density and preventing the cross-talk. A method and apparatus for reproducing the information recorded on the medium are provided.

Abstract: An optical recording control method determines an optimum recording laser power by effecting a test recording before information to be recorded is recorded on a disk. The recording laser power is formed of a plurality of powers. A relationship among the plurality of laser powers is regulated by power level ratios between respective powers, whereby a power used when a laser light is radiated on the disk can be controlled to be constant independent of an ambient temperature and a structure of a disk. Therefore, accurate recording marks can be formed on the disk.

Abstract: A photopolymerizable composition comprising at least an addition polymerizable compound having at least one ethylenically unsaturated double bond and a photopolymerization initiator system, which system comprises (a) a sensitizer of the formula (I): ##STR1## wherein each of R.sup.1 to R.sup.6 is hydrogen, halogen, alkyl, aryl, aralkyl, acyl, alkoxycarbonyl, optionally substituted hydrocarbon ring, optionally substituted heterocyclic residue or --SO.sub.3 --R.sup.8, wherein R.sup.8 is hydrogen, alkyl, aryl, aralkyl, alkali metal, or quaternary ammonium, R.sup.7 is hydrogen, alkyl, aryl, aralkyl, optionally substituted hydrocarbon ring, or optionally substituted heterocyclic group, each of X.sup.1 and X.sup.2 is halogen, alkyl, aryl, aralkyl, optionally substituted hydrocarbon ring, or optionally substituted heterocyclic group, and (b) a titanocene compound.

Abstract: In an information recording/reproducing apparatus constructed of: a buffer for storing therein consecutive recording data in a unit of two dimensional conversion; a coding device for converting the consecutive recording data into a two-dimensional data arrangement arranged by "n" lines and "m" columns corresponding to said unit of data; a recording device for subdividing said two-dimensional data arrangement arranged by "n" lines and "m" columns so as to be read out, and for controlling "m" pieces of light sources in accordance with these data series; and an optical apparatus for converging luminous fluxes from said "m" pieces of light sources so as to form "m" pieces of spots on a disk plane, the recording data is recorded on the disk plane as an optically distringuishable pit group having two-dimensionally extended areas arranged by "n" lines and "m" columns.

Abstract: A magneto-optical disk system includes a magneto-optical disk and a disk drive. The magneto-optical disk drives provides a function of controlling the shape of a recorded domain by using a short wavelength laser beam and a test recording and a function of recording a using a pulse train. The magneto-optical disk has a laminated layer structure capable of obtaining a high S/N ratio and stabilizing a heat conduction. The magneto-optical disk drive with the recorded domain shape control function using a short wavelength laser beam and a test recording and with the pulse train recording record function is organically coupled with the magneto-optical disk having the laminated layer structure with a stabilized heat conduction to make the disk and the disk drive have an integrity therebetween, providing a magneto-optical disk having a recording capacity four times as large as the first generation magneto-optical disk system.

Abstract: A magneto-optical disk recording control method using the mark length recording method wherein the marks and gap regions between marks are recorded on the surface of the disk by maintaining a constant temperature distribution during the recording. The laser is driven to a non-recording level in gap regions between marks that exceed a base recording level used for reproduction of the marks. When a mark is recorded, the laser power is increased to a recording power level and after the mark has been recorded, the laser power level is reduced to the base power level, followed by being raised to the gap recording level. Control of the laser is performed by superposing a plurality of pulse trains that are synchronized with respect to a clock having a cycle T. The pulse trains are derived from the code train to be recorded and have pulses with a duration that is an integral multiple of (1/2)T.

Abstract: A pit edge interval correcting method in an optical recording/read-out apparatus wherein as data items to be used to correct pit edge intervals for cancellation of a thermal interference from a previously recorded pattern, there is formed a table representing relationships between kinds of record patterns and edge shift quantities of the patterns in a read-out signal. Edge shift quantities of particular patterns with respect to a unitary variation quantity of a recording medium surface temperature (an ambient temperature of an optical disk) and edge shift quantities of particular patterns with respect to a unitary variation quantity of laser power are beforehand acquired as correction control data. Before actual data are recorded, the particular patterns are again recorded on a medium and read out therefrom.