Abstract: A disk apparatus performs optical recording onto an optical disk with a record mark by using a light beam modulated in a manner of multi-pulse series, includes. A detection pulse generating part generates a detection pulse to replace the multi-pulse series; and a detection power control part controls the power of the detection pulse to be smaller than the power of the multi-pulse series.

Abstract: In an information recording method and apparatus, when performing recording by using multiple pulses defined by erase powers Pe1 and Pe2 for forming a space part between mark parts, the set values of the erase powers Pe1 and Pe2 are updated at predetermined intervals in accordance with a recording linear velocity.

Abstract: An input bit sequence with predetermined bit periods T is converted into a corresponding light-emission waveform; and a beam with the thus-obtained light-emission waveform is applied onto a phase-change optical disk so as to record the input bit sequence thereon. The light-emission waveform comprises a heating pulse for heating the recording medium occurring for an interval tw and a cooling pulse for cooling the recording medium occurring for an interval tc, and the intervals tw and tc on the heating/cooling pulses satisfy the following requirement in case the heating/cooling pulses occur alternately with repetition: 1.5T≦tw+tc≦3T.

Abstract: A disk apparatus performs optical recording onto an optical disk with a record mark by using a light beam modulated in a manner of multi-pulse series, includes. A detection pulse generating part generates a detection pulse to replace the multi-pulse series; and a detection power control part controls the power of the detection pulse to be smaller than the power of the multi-pulse series.

Abstract: An information recording method records information on an optical disk by a recording pulse signal of an optical beam that is emitted from an optical source. A recording channel clock period T is changed depending on a change of a recording linear velocity so that a recording linear density is maintained approximately constant. In addition, a shape of a pulse waveform of a top heating portion of the recording pulse signal which includes a rear heating portion, is changed at predetermined intervals depending on a desired recording linear velocity, so that a width of the top heating portion and a recording power thereof are changed.

Abstract: A disk apparatus performs optical recording onto an optical disk with a record mark by using a light beam modulated in a manner of multi-pulse series, includes. A detection pulse generating part generates a detection pulse to replace the multi-pulse series; and a detection power control part controls the power of the detection pulse to be smaller than the power of the multi-pulse series.

Abstract: A disk apparatus performs optical recording onto an optical disk with a record mark by using a light beam modulated in a manner of multi-pulse series, includes. A detection pulse generating part generates a detection pulse to replace the multi-pulse series; and a detection power control part controls the power of the detection pulse to be smaller than the power of the multi-pulse series.

Abstract: An optical information recording method and apparatus which records information on a recording medium by irradiating the recording medium with an irradiation light of a recording power to form a recorded-mark on the recording medium such that reflection coefficient from an area of the recorded-mark is different than a reflection coefficient from an area of the recording medium where the recorded-mark is not formed by a changing power of the irradiation light.

Abstract: An information recording device comprising at least a recording pulse generating means and a recording pulse selecting means capable of generating various multi-pulses each of which is a combination of a leading heating pulse and a succeeding heating pulse, and rectangular pulses each of which is a single pulse, as a recording pulse, is disclosed. The recording pulse selecting means switches and selects among the multi-pulses and the rectangular pulses according to a recording condition, and then causes a light emission of a laser light source through a light source driving means. Even though in a high recording linear velocity recording condition that is insufficient in power for the recommended multi-pulse recording, a very low recording power can still be used by switching to the rectangular pulse recording, so as to achieve a recording with a much higher recording speed. In addition, good recording marks can be formed without exceeding a maximum allowable recording power.

Abstract: An optical information recording method and apparatus which records information on a recording medium by irradiating the recording medium with an irradiation light of a recording power to form a recorded-mark on the recording medium such that reflection coefficient from an area of the recorded-mark is different than a reflection coefficient from an area of the recording medium where the recorded-mark is not formed by a changing power of the irradiation light.

Abstract: An information recording method records information on an optical disk by a recording pulse signal of an optical beam that is emitted from an optical source. A recording channel clock period T is changed depending on a change of a recording linear velocity so that a recording linear density is maintained approximately constant. In addition, a shape of a pulse waveform of a top heating portion of the recording pulse signal which includes a rear heating portion, is changed at predetermined intervals depending on a desired recording linear velocity, so that a width of the top heating portion and a recording power thereof are changed.

Abstract: An input bit sequence with predetermined bit periods T is converted into a corresponding light-emission waveform; and a beam with the thus-obtained light-emission waveform is applied onto a phase-change optical disk so as to record the input bit sequence thereon. The light-emission waveform comprises a heating pulse for heating the recording medium occurring for an interval tw and a cooling pulse for cooling the recording medium occurring for an interval tc, and the intervals tw and tc on the heating/cooling pulses satisfy the following requirement in case the heating/cooling pulses occur alternately with repetition: 1.5T≦tw+tc≦3T.

Abstract: An optical recording method for an optical disk having a disk surface portion in which prepits, indicative of preformat information, are formed. In the optical recording method, a portion of a data signal which matches one of the prepits and corresponds to a write mark radially adjacent to one of the prepits is detected. Marks are recorded along a track of the disk by selectively using one of an optimal recording power and a proper recording power level, in accordance with the non-match portion or the match portion of the data signal. A radial width of the marks recorded in accordance with the match portion of the data signal is smaller than a radial width of the marks recorded in accordance with the non-match portion of the data signal. An optical reproducing method is adapted to accurately detect a wobble signal and a prepit signal from the optical disk to which data is recorded by the above optical recording method.

Abstract: An information recording method for recording information on an optical disk by a recording pulse train of an optical beam emitted by an optical source includes the steps of (a) changing a recording channel clock period T in accordance with a change of a recording linear velocity so that a recording linear density is kept constant, and (b) updating values of parameters Ttop, Tmp and &rgr; at intervals based on a desired recording linear velocity. A symbol Ttop is a ratio of a width of a top heating pulse in the recording pulse train to the recording channel clock period T. A symbol Tmp is a duty ratio of each heating pulse in a multi-pulse section following the top heating pulse. A symbol &rgr; is a ratio of a recording power Pw at the desired linear velocity to an optimal recording power Pwmin at a minimum recording linear velocity (&rgr;=Pw/Pwmin).

Abstract: An information recording method which forms marks or spaces based on the predetermined recording modulating method on a recording medium by radiating a light source using a multi-pulse line is disclosed. The information recording method comprises a head heating pulse and a head cooling pulse, followed by plural serial rear heating pulses and serial rear cooling pulses. The width of the rear heating pulse is constant in a view of time, regardless of the recording liner speed of the recording medium. When recording information comprising pulses N times as long as the channel clock cycle T by a laser ray from a laser source, the recording method uses constant angular velocity control comprising a constant recording frequency and a constant rotating angle velocity or zone constant angular velocity control which raises the recording frequency according to moving the laser ray to the outer area of each zone on the recording medium and a constant angle speed.

Abstract: A disk apparatus performs optical recording onto an optical disk with a record mark by using a light beam modulated in a manner of multi-pulse series, includes. A detection pulse generating part generates a detection pulse to replace the multi-pulse series; and a detection power control part controls the power of the detection pulse to be smaller than the power of the multi-pulse series.

Abstract: An optical information recording medium and a method of mastering an optical information recording medium. Cross-talk is avoided even when phase pits flanking a groove are radially aligned so that preformat information can be reliably reproduced after information is recorded at the grooves. A phase pit that encodes preformat information for a groove is radially spaced from that groove by a partition wall but is connected to an adjacent groove. When mastering, respective first and second exposing light beams are used to form the grooves and the phase pits, and the spacing between the two beams and, therefore, the width of the partition walls in the radial direction is precisely and easily controlled by controlling the inclination angle of at least one of the beams relative to an objective lens in the mastering exposure system.

Abstract: In an information recording system, information is recorded, through light from a light source, in a recording medium comprising a recording layer which has a phase reversibly changeable between a crystal phase and an amorphous phase. The light source emits, for forming a record mark in the recording layer, multi-pulse light which includes a head heating pulse, a head cooling pulse and following rear heating pulse and rear cooling pulse in the stated order. The head heating pulse includes a front division and a rear division. The difference in light-emission power between the head heating pulse and an immediately following cooling pulse is larger than the difference in light-emission power between another heating pulse and an immediately following cooling pulse.

Abstract: Disclosed herein is a liquid crystal display device comprising (1) a liquid crystal cell wherein a liquid crystal layer comprising a liquid crystal component having positive dielectric anisotropy is sandwiched between a pair of substrates having at least one electrode, (2) a pair of polarizers arranged to sandwich the liquid crystal layer therebetween and (3) a birefringence layer provided between the liquid crystal layer and the polarizer on at least one side of the liquid crystal layer, wherein the angle formed between the maximum refractive index direction in the birefringence layer face and the direction of transmission axis or absorption axis of polarizer adjacent to the birefringence layer is not more than 5.degree..

Abstract: A liquid crystal display device, comprising:(a) a liquid crystal layer disposed between a pair of light permeable substrates, an alignment of a liquid crystal of said liquid crystal layer being substantially horizontal relative to said substrates in the absence of applied voltage, said liquid crystal layer having a twisted structure with a twist angle along a direction of a thickness thereof such that an adequate display is provided without substantially reducing the time dimensional driving;(b) a pair of polarization means disposed on both outsides of said liquid crystal layer; and(c) at least one birefringent medium layer disposed between one side of said liquid crystal layer and the polarization means on said one side of said liquid crystal layer; an optical axis of said birefringent medium layer being inclined toward a polarization axis of the adjacent polarization means, the alignment direction of said liquid crystal on a surface of another side of said liquid crystal layer making an angle from 0.degree.