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Koichi Watanabe, Hachioji JP

Koichi Watanabe, Hachioji JP

Patent application numberDescriptionPublished
20080298194Optical disc apparatus and data recording method thereof - In order to ensure recording quality while suppressing the adverse effects due to performance variations among apparatuses and disc radial positions on an optical disc, an optical disc apparatus according to the present invention performs, at the time of data recording, the steps of: acquiring a jitter value and β value from a reproduced signal based on laser light reflected from the optical disc in relation to a disc radial position; learning a β value when the acquired jitter value is a minimum as a target β value; and, if a jitter value acquired thereafter is larger than the minimum jitter value by a preset reference value or above, correcting recording power based on the magnitude relation and the difference between the β value associated with the acquired jitter value and the target β value or performing trial record processing.12-04-2008
20090052306Semiconductor Laser Generator and Method of Controlling the Same, and Optical Disk Device - The present invention provides a laser generator that allows recording quality to be improved, a method of controlling the laser generator, and an optical disk device. In a laser emitting device including a semiconductor laser diode emitting laser and a semiconductor laser diode driving section supplying a driving pulse to the semiconductor laser diode to drive the semiconductor laser so as to blink on the basis of the driving pulse, an impedance between the semiconductor laser diode and the semiconductor laser diode driving section is controlled to an appropriate condition.02-26-2009
20090080301Method of Recording Information On and Reproducing Information From Optical Disk and Apparatus for the Same - There is provided an information recording and reproducing method and an apparatus for the same capable of optimizing the shift adjustment of a recording pulse recorded in an optical disk even at the time of recording information on the optical disk at a high speed. The shift adjustment value of the recording pulse optimized at a low speed recording on an optical disk is multiplied by a constant value to be taken as the optimum shift conditions of the recording pulse at the high speed recording.03-26-2009
20090103106OPITCAL PICKUP - To reduce a bad influence on a tracking control signal and a data signal by reflected light from an adjacent layer on a multi-layer disc as stray light, the following device is made in the invention. Reflected light from the multi-layer optical disc including stray light from another layer is once converged by a reflected light condenser lens and is reflected on a reflector. A grating which prevents zero-order light from being generated by setting groove depth to λ/4 and which is set to pitch to prevent positive and negative first- or higher-order diffracted lights from returning to the reflected light condenser lens is arranged between the lens and the reflector including an optical axis with the grating apart from the reflector. Hereby, as reflected light from another layer is cut off though reflected light from a corresponding layer is transmitted to a detector, a detected control signal and a detected data signal are not influenced by reflected light from another layer.04-23-2009
20090154326Optical recording and reading equipment - Disclosed herewith is a data recording and reading equipment capable of reducing laser noise easily. At first, a laser beam source that can reduce the laser noise when reading data from a subject optical disk is obtained. A modulator capable of varying laser attenuation with a voltage is disposed so as to precede the laser, thereby the laser noise when reading data from the optical disk can be reduced without lowering the laser power when in writing.06-18-2009
20100061206OPTICAL INFORMATION RECORDING METHOD - To solve the problem of deterioration in recording quality due to a change of a write waveform caused by changes of temperature and recording powers, aged deterioration and the like. A driver having a function of controlling rise/fall times and an overshoot amount of an optical waveform is used to optimize an optical waveform that changes in recording under the influence of a component of a laser and the like. Specifically, the rise/fall times and the overshoot amount of the optical waveform are optimized by obtaining a waveform control register value from test recording or a table.03-11-2010
20100157770OPTICAL DISC DRIVE AND OPTICAL INFORMATION READ METHOD - An HF waveform prevailing during a read operation varies due, for instance, to changes in the ambient temperature of an optical disc drive and variations in the characteristics of a laser. This degrades read performance and decreases the number of rewritable disc read operations. To address the above problems, an optical disc drive and an optical information read method are disclosed. The disclosed optical disc drive and optical information read method vary an HF amplitude in relation to the resistance, differential resistance, or temperature of the laser.06-24-2010
20100195459Adjustment Method Of Optimum Write Power And Optical Write/Retrieval Device - A power adjustment method in which a modulation index is calculated from reproduced signals of patterns recorded by irradiating light onto an optical information recording medium with a recording power varied and an optimum power of irradiation light is set up using the modulation index. The power adjustment method includes calculating an optimum value PcO of a predetermined correction term Pc using a relation of a value obtained by subtracting the predetermined correction term Pc from the recording power and the modulation index, finding a value Pth of the recording power at which the modulation index becomes substantially zero in the relation of the value obtained by subtracting the optimum value PcO from the recording power and the modulation index, and setting up a value obtained by multiplying the value of Pth by a predetermined constant as a recording power of each of the recording patterns.08-05-2010
20100309764MULTILAYERED OPTICAL DISK AND ITS RECORDING METHOD - To provide a recording method of a multilayered optical disk having three or more recording layers, for performing recording while securing sufficient test areas without reducing user data areas, and while suitably controlling the power of laser beam irradiated onto each of the layers. The method uses an optical disk which has at least a first recording layer and a second recording layer located on the side nearer to the light incident surface than the first recording layer, and which respectively has a first test area configured by a plurality of segments in the first recording layer and a second test area configured by a plurality of segments in the second recording layer. Further, the method is configured such that there is defined beforehand a predetermined radial distance L corresponding to relative precision of radial positions between the plurality of layers and the optical spot diameter, and that when an arbitrary segment in the second test area is test-recorded, a segment in the first test area, the radial distance of which from the recorded test area in the second test area is within the range of the predetermined radial distance L, is set as a segment in which the test recording is not performed. Thereby, even in the case where the radial positions of the test areas of the plurality of layers are substantially overlapped with each other, it is possible to precisely perform the learning of optical power. For this reason, it is possible to use and arrange the test areas of the plurality of layers without waste. Further, the learning of recording power can be performed without receiving the influence of the recorded state of the other layers, so that the accuracy of the learning of recording power can be improved. Thereby, it is possible to improve the quality of recording and the reliability of recorded data.12-09-2010
20110002204POWER ADJUSTMENT METHOD, INFORMATION WRITE METHOD AND INFORMATION WRITE MEDIUM - A write power adjustment method makes it possible to set optimum write power with high precision. Trial writing is conducted by using write power Pw,m (where m is an integer) of a plurality of kinds, and a modulation M,m associated with each write power is calculated. Optimum asymptotic power Pasy-opt is calculated by performing predetermined computation by using reference asymptotic power Pasy-ref and reference write start power Pws-ref which are previously determined for each medium. An evaluated value S,m=M,m×(Pw,m−Pasy-opt) is calculated by using the optimum asymptotic power Pasy-opt. Write power Pw that makes the evaluated value S equal to zero when applying straight line approximation to a relation between the write power Pw,m and the evaluated value S,m is calculated as optimum write start power Pws-opt. And optimum write power Pw-opt is found by performing predetermined computation on the optimum write start power Pws-opt.01-06-2011
20110002214OPTICAL INFORMATION RECORDING AND REPRODUCING METHOD AND OPTICAL INFORMATION RECORDING AND REPRODUCING APPARATUS - An optical information recording and reproducing method for recording or reproducing information by irradiating pulsed laser diode light from a laser diode (LD) light source in which the resistance value of the LD light source is measured in an operating state, the measured LD light source resistance value is compared with a target resistance value, and the LD light source is heated when the LD light source resistance value is higher than the target resistance value, in order to maintain the LD light source resistance at a specified value or less.01-06-2011
20110080815OPTICAL RECORDING AND REGENERATING APPARATUS - The present invention achieves an optical recording and regenerating apparatus focusing two opposed beams of light at a same place in an optical recording medium to record a standing wave generated by interference of the two beams of light. In the apparatus, phase information is recorded in the optical recording medium by a phase modulating means for modulating phase of one of the two beams of light. The generation reference light generated from a light source is allowed to interfere with regenerated light generated by projecting one of the two beams of light onto the optical recording medium to generate three or more beams of interfering light having different interference phases are simultaneously generated. The three or more beams of interfering light are then detected, and the phase modulated by the phase modulating means is demodulated from an output of the detector.04-07-2011
20110110204VARIABLE MIRROR ACTUATOR AND OPTICAL DISC DRIVE - A pickup and a drive, in a small size, having a spherical aberration correction device capable of correcting various spherical aberration, and coma aberration and/or astigmatism with a low power consumption. A variable-focus lens actuator can correct spherical aberration such that a transparent deformation film warps into a parabolic shape when a magnetic field is applied thereto, thereby changing the light intensity distribution of transmitted light. Further, the variable-focus lens actuator can correct coma aberration and/or astigmatism by arbitrarily tilting the transparent film to change the proceeding direction of the transmitted light.05-12-2011

Patent applications by Koichi Watanabe, Hachioji JP