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公开(公告)号：JPH0482051A
公开(公告)日：1992-03-16
申请号：JP19474290
申请日：1990-07-25
Applicant: SONY CORP
Inventor： SAEKI HIROSHI , UDAGAWA TOSHIKI
Abstract: PURPOSE:To eliminate a need of focus search operation by using the light from a light source in a skew sensor and comparing the signal level, which is obtained by receiving the return light from a disk by a photodetector, with a prescribed reference level to discriminate the disk type. CONSTITUTION:The light from a light emitting diode 2c in a skew sensor 2 is reflected by a disk 1, and the return light is received by two-divided photo diodes 2A and 2B, and the total sum signal of quantities of light received by these photo diodes is outputted from an adder 5 of a skew servo system. The output signal from the adder 5 is supplied to one input terminals of each of three comparators 19 to 21 for disk type discrimination. Reference voltage from three reference voltage sources 15 to 17 are supplied to the other input terminals of comparators 19 to 21. These reference voltages La to Lc are so set that the difference in level of the sum signal of quantities of return light based on the difference in reflectivity of the disk can be discriminated. Thus, the disk type is discriminated in a short time.
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公开(公告)号：JPH0354737A
公开(公告)日：1991-03-08
申请号：JP19088189
申请日：1989-07-24
Applicant: SONY CORP
Inventor： OSATO KIYOSHI , UDAGAWA TOSHIKI , OKADA HITOSHI
Abstract: PURPOSE:To expand the pull-in range and the valid control range of tracking servo control by providing a signal forming circuit part where a signal obtained from a first signal which shows a tracking state and a second signal which substantially has the phase difference of 90 deg. from the first signal is obtained as a tracking error signal. CONSTITUTION:An optical recording and/or reproducing device is constituted of the signal forming circuit 40 where the first signal S1 showing the tracking state of a recording track part on the disk-like recording medium of a light beam and the second signal S2 substantially having the phase difference of 90 deg. from the signal S1 are obtained based on a detection output obtained from a light detection part 14 and a signal S3 obtained according to a formula I, provided as (K>=1), is obtained as the tracking error signal. Thus, the pull-in range to a servo control state and the following valid control range is set by an inclined part in a waveform which is nearly a saw-tooth-wave and the tracking servo control is expanded.
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公开(公告)号：JP2002358640A
公开(公告)日：2002-12-13
申请号：JP2001158871
申请日：2001-05-28
Applicant: SONY CORP
Inventor： UDAGAWA TOSHIKI , NISHIURA TARO
IPC: G11B7/1263 , G11B7/00 , G11B7/004 , G11B7/0045 , G11B7/125
Abstract: PROBLEM TO BE SOLVED: To obtain an optimum recording laser power condition in real time corresponding to the environmental condition relating to mark formation. SOLUTION: At the time of data recording operation (formation of mark) performed by applying a pulse train-like laser output to a recording medium of organic coloring material, a 1st signal value corresponding to a leading pulse in the pulse train-like laser output and a 2nd signal value corresponding to after 2nd pulse in the pulse train-like laser output are detected as a reflected light information signal to obtain the ratio, and a laser power correcting signal is produced by using the obtained value of ratio and the referenced value of ratio, then the laser output power is controlled.
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公开(公告)号：JP2002124031A
公开(公告)日：2002-04-26
申请号：JP2000311327
申请日：2000-10-11
Applicant: SONY CORP
Inventor： UDAGAWA TOSHIKI
IPC: G11B20/10
Abstract: PROBLEM TO BE SOLVED: To provide a data reproducing device and a data reproducing method which can easily improve the reliability of reproduced data. SOLUTION: In the data reproducing device and the data reproducing method which binarize an alternate current(AC) signal obtained by reading data recorded on a recording medium by using the center of amplitude of the AC signal as a slice level, a direct current(DC) component is removed from the AC signal. The signal processing of a prescribed second signal characteristic which offsets a first signal characteristic given to the AC signal when the DC component is removed from the AC signal, is applied to the AC signal from which the DC component is removed. Either of the AC signal from which the DC component is removed and the AC signal to which the signal processing is performed, is binarized selectively. The AC signal is monitored, and the AC signal to which the signal processing is performed only when the signal level of the AC signal fluctuated more than a prescribed threshold, is binarized.
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公开(公告)号：JP2000057577A
公开(公告)日：2000-02-25
申请号：JP24390299
申请日：1999-08-30
Applicant: SONY CORP
Inventor： FUKUMOTO ATSUSHI , UDAGAWA TOSHIKI , YOSHIMURA SHUNJI , ONO MASUMI , YASUDA KOICHI
Abstract: PROBLEM TO BE SOLVED: To increase linear recording density and to increase recording capacity of a medium by forming a prescribed relation among the shortest pit interval along a scan direction of a read-out light beam, the wavelength of the read-out light beam and a numerical aperture of an objective lens. SOLUTION: An optical recording medium forming a phase pit according to a signal and changing a reflectance according to a temperature is irradiated by the read-out light beam, and the phase pit is read while partially changing the reflectance in the scan spot of the read-out light beam. In such a optical recording medium, the shortest phase pit interval of a recording signal along the scan direction of the read-out light beam is made λ/2NA or below when the wavelength of the read-out light beam is defined λ, the numerical aperture of the objective lens is NA. By such a optical recording medium, recording density in the scan direction of the light beam of a laser beam, etc., that is, the linear recording density, is increased by making a pit arrangement interval (recording pit interval) in this direction λ/2NA or below.
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Patent Agency Ranking
公开(公告)号：JPH10241201A
公开(公告)日：1998-09-11
申请号：JP4447297
申请日：1997-02-27
Applicant: SONY CORP
Inventor： SAKAMOTO SATOSHI , SUZUKI JUNICHI , UDAGAWA TOSHIKI , YAMAZAKI MICHIKO
Abstract: PROBLEM TO BE SOLVED: To enable aberration compensations at the time of reading out information from plural kinds of recording medium whose thickness of optically transparent layers are different by moving operate a compensating element for compensating the spherical surface of an objective lens to be provided at an entrance pupil side with respect to the objective lens over the inside and the outside of an optical path with a linearly driving mechanism. SOLUTION: A linearly driving coil 12 is provided in a slide mechanism to generate a driving force in a linear direction by being combined with a magnetic flux to be generated from a linearly driving magnet and moves a corrected lens holder provided with a corrected lens 14. The corrected lens 14 is supported in a lens holder and is a lens compensating the aberration due to the kind of an optical recording medium 101 and is moved in the linear direction with the slide mechanism as necessary to be inserted into an optical path being directly under and objective lens 38. The lens holder is of the flate rectangular parallelepiped plate shape integrally formed in the slide mechanism part and is provided with the corrected lens 14 and the center of the principal plane.
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公开(公告)号：JPH06164046A
公开(公告)日：1994-06-10
申请号：JP30910192
申请日：1992-11-18
Applicant: SONY CORP
Inventor： MASUDA HISASHI , UDAGAWA TOSHIKI , SUGIURA MINAKO
Abstract: PURPOSE:To stably radiate a wavelength-converted laser beam by a method wherein the wavelength-converted laser beam which is radiated to the side of an excitation light source from a resonance block is taken out, an error signal is obtained from the taken-out laser beam, the error signal is negatively fed back and the drive of the excitation light source is controlled. CONSTITUTION:The backward radiated beam of a second-harmonic laser beam generated by a resonator 8 is transmitted through an excitation laser beam, it is reflected by a wavelength separation mirror 3 which reflects the second- harmonic laser beam, and it is taken out by a photodetector 4. An error signal between a signal obtained from its high-frequency component and a reference voltage is negatively fed back, it is added to a constant-current dribe circuit at a timing at which a temperature control system is operated, and it drives a laser diode 1. When the driving current of the laser diode 1 is controlled, the generation of the second-harmonic laser beam can be controlled, and a noise level can be reduced on the low-frequency side of the second-harmonic laser beam.
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公开(公告)号：JPH05234107A
公开(公告)日：1993-09-10
申请号：JP6101692
申请日：1992-02-18
Applicant: SONY CORP
Inventor： UDAGAWA TOSHIKI , FUKUMOTO ATSUSHI
Abstract: PURPOSE:To realize an excellent tracking operation even for any optical disk of plural kinds of optical disks having different track pitches. CONSTITUTION:Side spots 21a, 22a, 21b, 22b are obtained which respectively correspond to plural kinds of the optical disks 17a, 17b having different track titchs by using plural kinds of diffraction gratings 2a, 2b dividing a laser beam in an optical pickup device. In accordance with the track pitch of optical disk loaded, the output signals from photodetectors 10a, 11a, 10b, 11b corresponding to various kinds of side spots respectively are selected and a tracking error signal TE is detected.
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公开(公告)号：JPH0589506A
公开(公告)日：1993-04-09
申请号：JP27652391
申请日：1991-09-27
Applicant: SONY CORP
Inventor： NAGARA TORU , UDAGAWA TOSHIKI , YOSHIMURA SHUNJI
IPC: G11B7/125 , G11B11/10 , G11B11/105
Abstract: PURPOSE:To most suitably control the laser beam power of a magneto-optical disk recording and reproducing device according to the surrounding temperature and the recording pattern. CONSTITUTION:A part of the emitting light of laser beam is sampled at first and second timings and within a range wherein the output power is changed linearly to the driving current, the upper and lower limits of the output power level of the laser beam are held in sample-hold circuits 3a and 3B. The full scale of a D/A converter 9 is set so that the laser beam is controlled within the range between the upper and lower limits.
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公开(公告)号：JPH04259943A
公开(公告)日：1992-09-16
申请号：JP4289091
申请日：1991-02-15
Applicant: SONY CORP
Inventor： UDAGAWA TOSHIKI , FUKUMOTO ATSUSHI , YOSHIMURA SHUNJI
IPC: G11B11/10 , G11B11/105
Abstract: PURPOSE:To record/reproduce a conventional magneto-optical disk (MO disk) by the recording and reproducing device for a new magneto-optical disk (MSR disk) which can be applied an erase type or float type reproducing method and enables recording and reproducing with high recording density. CONSTITUTION:The MSR disk and the MO disk are identified by a disk class identifying means 70, the identifying output is supplied to a system controller 40. According to the output of this system controller 40, a channel clock generation circuit 62 is controlled and switched to a channel clock frequency corresponding to the linear recording density of the both disks. An optical system is shared between the MSR disk and the MO disk.
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