Abstract: In a recording/reproducing apparatus and a recording method, for enabling a high reliability on reproduction data are conducted the followings: recording a test mark within the test aria with a predetermined write strategy; obtaining signal amplitudes corresponding to a front portion, a middle portion, and a rear portion of the test mark, by reproducing the test mark; determining on whether the test mark has a desirable configuration or not, upon basis of at least one of ratios, defined between the amplitude of the front portion and the amplitude of the rear portion, and between the amplitude of the middle portion and the amplitude of the rear portion; correcting the write strategy if it is determined that the test mark has not the desirable configuration; and recording the information within the data area with the write strategy after the correction thereof.

Abstract: In reproduction of a two-dimensional page data from an optical information recording medium utilizing holography, a reproduced two-dimensional page data is divided into a plurality of areas each of which has a predetermined size, the divided two-dimensional areas are individually subjected to adaptive equalizing, and then are coupled to restore the condition of the original two-dimensional page data.

Abstract: A signal quality evaluating method necessary for a signal quality evaluation index and a margin design is provided for an apparatus utilizing hologram recording techniques. An evaluation index is used being obtained by dividing root sum square of standard deviations of luminance value distribution of on- and off-pixels obtained from reproduced signals, by a difference between average values.

Abstract: In a holographic memory of an angle multiple recording system, when a hologram is reproduced, a light beam of a different polarizing direction is irradiated as reference light to a hologram recording medium and diffracted light is detected from the hologram recording medium.

Abstract: A holographic memory apparatus comprises first phase modulation means that adds phase information to each pixel of a signal beam to generate page data at recording time; oscillator light generation means that generates an oscillator light that is superimposed on, and interferes with, a diffracted light from a holographic recording medium at reproduction time; second phase modulation means that adds phase information to the oscillator light; and light detection means that detects an interference light generated by superimposing the oscillator light and the diffracted light from the holographic recording medium.

Abstract: In an optical information reproduction method for reproducing information using holography from a medium which records an interference pattern generated when overlapping a signal beam and a reference beam, the reference beam is radiated to the medium at a reference beam angle with a predetermined range for reproducing the information, a reproduction beam is generated by diffracting the reference beam with the interference pattern, the reproduction beam is detected by a photodetector; and the information is reproduced by processing a signal detected by the photodetector.

Abstract: An optical beam with the same amplitude distribution and phase distribution as those of the signal beam used for recording is radiated to the hologram recording medium via an optical system of the signal beam prior to reproduction so that the optical beam with the amplitude and phase of the reference beam upon recording is generated through diffraction. A wavefront sensor detects the wavefront configuration of the diffraction beam and obtains preliminarily the suitable wavefront of the reference beam for reproduction. The wavefront control element preliminarily corrects the wavefront of the reference beam to an optimum wavefront.

Abstract: In case of reproducing a hologram recorded on an optical information recording medium, adjusting beam with the amplitude distribution and phase distribution at least partially the same as those of a signal beam upon recording is radiated to the optical information recording medium which records information. The diffracting beam diffracted by the hologram is detected by a photodetector. Based on the detected information, an incident angle of the reference beam to the optical information recording medium is appropriately controlled.

Abstract: Provided is an optical disk device capable of recording and/or reproducing information on optical disks with high reliability; and a method for controlling the optical disk device. The position of an optical lens where the amplitude of a reproduction signal during the period corresponding to a minimum-length recording mark and a space having the same length reaches its maximum is detected; and the detected position is set as a reference position for the objective lens relative to the optical disk, for use in focus control. Also, the position of the objective lens where the result of multiplication of resolution and modulation becomes greatest is detected; and the detected position is set as a reference position for the objective lens relative to the optical disk, for use in focus control.

Abstract: A signal quality evaluating method necessary for a signal quality evaluation index and a margin design is provided for an apparatus utilizing hologram recording techniques. An evaluation index is used being obtained by dividing root sum square of standard deviations of luminance value distribution of on- and off-pixels obtained from reproduced signals, by a difference between average values.

Abstract: In a CAV recording of an optical disk, when a plurality of zones are provided, a write strategy is matched for a change in recording linear velocity in the zone so that recording quality can be assured, and recording power is controlled. The write strategy (pulse timing and power ratio) is optimized at the highest recording linear velocity of each zone and the setting of the power in each zone is controlled so that a relation between a recording linear velocity V and a recording power Po satisfies Po=CV (C is a coefficient which is obtained from the relation between Po and V at a zone end point), thereby assuring the reliability of recorded information.

Abstract: Provided is an optical disk device capable of recording and/or reproducing information on optical disks with high reliability; and a method for controlling the optical disk device. The position of an optical lens where the amplitude of a reproduction signal during the period corresponding to a minimum-length recording mark and a space having the same length reaches its maximum is detected; and the detected position is set as a reference position for the objective lens relative to the optical disk, for use in focus control. Also, the position of the objective lens where the result of multiplication of resolution and modulation becomes greatest is detected; and the detected position is set as a reference position for the objective lens relative to the optical disk, for use in focus control.

Abstract: In a recording/reproducing apparatus and a recording method, for enabling a high reliability on reproduction data are conducted the followings: recording a test mark within the test aria with a predetermined write strategy; obtaining signal amplitudes corresponding to a front portion, a middle portion, and a rear portion of the test mark, by reproducing the test mark; determining on whether the test mark has a desirable configuration or not, upon basis of at least one of ratios, defined between the amplitude of the front portion and the amplitude of the rear portion, and between the amplitude of the middle portion and the amplitude of the rear portion; correcting the write strategy if it is determined that the test mark has not the desirable configuration; and recording the information within the data area with the write strategy after the correction thereof.

Abstract: To provide a technology for improving the recording quality through edge correction of recording pulse in an optical disc apparatus. An optimum recording power of recording pulse is obtained through OPC processing according to a recording strategy with a first pulse timing; recording is performed by use of recording pulse with the optimum recording power; a first edge-shift amount of recording mark is measured from a reproduction signal to perform edge correction of recording pulse to form a second pulse timing of a recording strategy. Subsequently, recording is performed with pulse width variations of recording pulse to measure a second edge-shift amount of recording mark from a reproduction signal; and optimum edge positions of recording pulse are calculated based on the first edge-shift amount and the second edge-shift amount.

Abstract: In a CAV recording of an optical disk, when a plurality of zones are provided, a write strategy is matched for a change in recording linear velocity in the zone so that recording quality can be assured, and recording power is controlled. The write strategy (pulse timing and power ratio) is optimized at the highest recording linear velocity of each zone and the setting of the power in each zone is controlled so that a relation between a recording linear velocity V and a recording power Po satisfies Po=CV (C is a coefficient which is obtained from the relation between Po and V at a zone end point), thereby assuring the reliability of recorded information.

Abstract: Random data is recorded on a higher-level recording layer and then, an optimum recording power is determined on a lower-level recording layer corresponding to the higher-level recording layer. Accordingly, it is necessary to record random data in more areas on the higher-level recording layer than areas for determining the optimum recording power on the lower-level recording layer. Consequently, there is a problem that the areas for determining the optimum recording power are excessively wasted.

Abstract: The present invention provides a short-circuit protecting circuit of a switching regulator which does not require a capacitor having a large capacity in order to obtain a sufficient duty time. A pulse generating circuit for generating one clock with a short-circuit detection signal as a trigger signal is added, and a counter circuit for counting clock pulses of a clock signal is further inserted between a comparator and a latch circuit, whereby it becomes possible to produce a sufficient delay time based on a signal having a short period using a capacitor having a small capacity.

Abstract: The present invention provides a short-circuit protecting circuit of a switching regulator which does not require a capacitor having a large capacity in order to obtain a sufficient duty time. A pulse generating circuit for generating one clock with a short-circuit detection signal as a trigger signal is added, and a counter circuit for counting clock pulses of a clock signal is further inserted between a comparator and a latch circuit, whereby it becomes possible to produce a sufficient delay time based on a signal having a short period using a capacitor having a small capacity.

Abstract: A semiconductor integrated circuit device capable of avoiding noise generation and suppressing occurrence of an erroneous operation. Provided is a current limiting circuit where a current flowing in an output terminal of a charge pump circuit is sensed with a sensing resistor to be detected by a current detecting circuit to thereby cause an input current to constantly flow in an input terminal of the charge pump circuit in an amount approximately twice larger than an output current, whereby a current is kept constant to suppress a peak current and to avoid the noise generation. Consequently, other circuits connected to an input power source shared with the charge pump circuit are kept from erroneously operating.

Abstract: An optical disc recording and reproducing apparatus are provided in which even if a focusing error signal fluctuates suddenly by surface deflection or an obstacle such as scratch or dust on the surface of an optical disc, an effective recording laser power does not decrease but proper recording, erasure, and reproduction can be executed. An ordinary laser power for recording and a laser power for defocus, that is, a laser power larger than the ordinary recording laser power by a predetermined magnification are preset into a laser driver. In the normal case where a focusing error lies within a predetermined range, the former laser power is used. When the focusing error exceeds the predetermined range and the effective laser power is decreased by the defocus, the latter laser power is used.