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 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 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: An information recording medium includes an information recording layer on which at least information is to be recorded by irradiating light, and a light transmission restricting layer which has a plurality of nonlinear transmission characteristics or nonlinear reflection characteristics for the intensity of the light irradiated and which has an optical material for restricting the transmission or reflection of the light according to the respective characteristics when the light is irradiated onto the information recording layer. An information recording and reproducing unit uses the information recording medium and includes an information recording position setting unit for deciding a position at which information is to be recorded on the information recording medium by detecting a direction of an easy magnetization axis.

Abstract: When record marks are recorded on a recording medium while making a code symbol "1" of data by obtained coding write information according to a coding system having no DC free property correspond to every edge of the record marks, the recording is effected while inserting resynchronizing signals into the write information with a constant interval. For the resynchronizing signal either one selected between a first resynchronizing code pattern, in which the number of symbols "1" contained therein is even, and a second resynchronizing code pattern, in which the number of symbols "1" is odd, so that an accumulated charge obtained from the run length of the coded data approaches zero is used. Each of the first and the second resynchronizing code pattern contains at least a specified pattern, which doesn't meet the coding rule.

Abstract: A magneto-optical recording device for radiating a laser beam according to recording information onto a magneto-optical recording medium having an easy axis of magnetization in a direction perpendicular to a film face of the recording medium itself to form a reversed domain and record information, which forms a reversed domain by radiating a laser beam and moves the position of the reversed domain to record information. In an embodiment of the present invention, it becomes possible to over-write new information without erasing beforehand information already recorded by only controlling the intensity, pulse width, radiation position and radiation time of the laser beam without providing a special bias magnetic field for reversing the magnetic field.

Abstract: An optical recording/ reproducing method which is characterized by irradiating a magnetic material having a perpendicular anisotropy with a laser beam to cause a change in the perpendicular anisotropy in the magnetic material to a non-perpendicular anisotropy thereby to record information; and by reproducing the information by detecting a change in a magneto-optic effect such as the Kerr effect. Also disclosed are an optical recording material and an optical recording device for use in the optical recording/reproducing method.

Abstract: A magnetic field of a polarity corresponding to information to be recorded is applied while a recording spot having a high energy is irradiated to a magneto-optical recording medium to record domains representing the information along a track. The recorded domains are read out by a reproducing spot having a lower energy than the recording spot and a high resolution power along the track.

Abstract: A magneto-optical recording medium comprising a perpendicularly magnetized amorphous film made of an alloy of the formula: (R.sub.1-x M.sub.x).sub.a (Fe.sub.1-y Co.sub.y).sub.100-a, wherein R is at least one of La, Ce, Pr, Nd, Sm, Ho, Er and Yb; M is at least one of Tb, Gd and Dy; 0.ltoreq.x<0.5; 0<y<1; and 10.ltoreq.a.ltoreq.40, is large in the Kerr rotation angle, excellent in coercivity and affords a larger read output-to-noise ratio (C/N).

Abstract: A compact, light-weight all solid state lithium battery is disclosed. The battery provides a good contact between a solid electrolyte and a Li anode by forming a Li alloy layer therebetween, even at the time of discharge at a large current density.

Abstract: A cathode structure for a thin film battery in which a titanium oxide layer is disposed on a substrate and has a titanium disulfide thin film disposed thereon. The cathode structure exhibits an excellent performance when applied to a lithium battery, a sodium battery, etc.