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21. 发明专利

JP2840484B2 失效
公开(公告)号：JP2840484B2
公开(公告)日：1998-12-24
申请号：JP16581091
申请日：1991-07-05
申请人： SANYO DENKI KK
发明人： TSUJIOKA TSUYOSHI
IPC分类号： G11B7/00 , G11B7/0045 , G11B7/0055 , G11B7/135 , G11B7/20 , G11B7/30

22. 发明专利

JPH10268180A OBJECTIVE LENS DRIVE DEVICE FOR OPTICAL HEAD 失效
公开(公告)号：JPH10268180A
公开(公告)日：1998-10-09
申请号：JP7117797
申请日：1997-03-25
申请人： TOSHIBA CORP
发明人： MAEDA SATORU
IPC分类号： G02B7/08 , G02B7/09 , G02B7/28 , G02B13/00 , G11B7/085 , G11B7/135 , G11B7/20
摘要： PROBLEM TO BE SOLVED: To provide an objective lens drive device for an optical head, capable of reducing the travel distance of an objective lens beyond an intended position, and keeping the objective lens at the position more quickly at the time of driving the objective lens for a travel to the intended position at high speed. SOLUTION: A zero-cross detection circuit 14 detects the cross of a focus error signal from a focus error detection circuit 12 with a zero level, or the arrival of an objective lens 11b at a focusing position during the high-speed travel thereof to the focusing position, thereby keeping the objective lens 11b at an intended position, depending on the focus error signal. In this case, the focus error signal is time differentiated through a differential compensation circuit 16. A signal for the appearance of a zero level at a time earlier than the arrival of the focus error signal at the zero level is thereby generated, and sent to the zero-cross detection circuit 14.

23. 发明专利

JPH10261241A RECORDING/REPRODUCING DEVICE AND METHOD THEREOF 失效
公开(公告)号：JPH10261241A
公开(公告)日：1998-09-29
申请号：JP6585197
申请日：1997-03-19
申请人： SONY CORP
发明人： ABE TSUGUHIRO
IPC分类号： G11B7/00 , G11B7/005 , G11B7/135 , G11B7/20
摘要： PROBLEM TO BE SOLVED: To contemplate the realization of a miniature device capable of repro ducing both DVD(digital versatile disk) and CD(compact disk)-R. SOLUTION: A laser chip 21B emitting the laser beam of 650nm wavelength at the time of reproducing the DVD 41B is arranged on an optical axis of a dioptric objective lens 26. A laser chip 21A emitting the laser beam of 780nm wavelength at the time of reproducing the CD 41A is arranged out of the optical axis. The laser beam emitted from the laser chip 21A for reproducing the CD is diffracted by a holographic optical element(HOE) 25a for synthesizing an optical path and synthesized on the optical axis by correcting the coma aberration. The spherical aberration of this beam is corrected by an HOE 25b then the beam, is made incident on the CD 41A through the dioptric objective lens 26.

24. 发明专利

JPH10188342A OPTICAL INFORMATION RECORDING MEDIUM AND REPRODUCING DEVICE THEREFOR 失效
公开(公告)号：JPH10188342A
公开(公告)日：1998-07-21
申请号：JP33969196
申请日：1996-12-19
申请人： NIPPON COLUMBIA
发明人： ONISHI ATSUSHI
IPC分类号： G11B7/005 , G11B7/00 , G11B7/135 , G11B7/20 , G11B7/24
摘要： PROBLEM TO BE SOLVED: To provide an optical information recording medium capable of reducing the possibility of being not reproduced due to the damage or the like on the reproducing surface. SOLUTION: The same information is recorded on a first information surface 102 of a first transparent resin substrate 101 and a second information surface 106 of a second transparent resin substrate 107 with the radial positions having a slight deviation. Note that these recordings are made at different positions in a planer view. 103 is a semitransparent layer, 104 is an adhesive layer and 105 is a reflection layer. The surfaces 102 and 106 are reproduced by the reproducing laser light beams emitted from the bottom. Thus, even though the reproducing of the surface 102 is not possible due to the scratches on the disk surface, the same information is recorded on the surface 106 and therefore, the information is continuously reproduced by changing the spot position of the reproducing laser light beams.

25. 发明专利

JPH10177738A OPTICAL PICKUP DEVICE 失效
公开(公告)号：JPH10177738A
公开(公告)日：1998-06-30
申请号：JP33661896
申请日：1996-12-17
申请人： SANKYO SEIKI SEISAKUSHO KK
发明人： YANAGISAWA KATSUSHIGE
IPC分类号： G11B7/135 , G11B7/20
摘要： PROBLEM TO BE SOLVED: To provide an optical pickup device capable of forming a light spot of equal size and shape on a side of a photodetector through a return optical system even in the case of switching to an answering image forming optical system for reproducing a different kind of optical recording medium. SOLUTION: In the optical pickup device capable of reproducing a DVD (digital video disk) and a CD(compact disk), a DVD image forming optical system and a CD image forming optical system are constituted by switching a DVD reproducing objective lens 71 to a CD reproducing objective lens 72. When the numerical aperture of the focal distance of the DVD reproducing objective lens 71 are defined NA1, f1, and the numerical aperture and the focal distance of the CD reproducing objective lens 72 are NA2, F2, these values are set beforehand so as to be satisfied substantially with the relation: NA1.f1= NA2.f2. Thus, since the numerical apertures of the return optical systems aren't changed even when either image forming optical system is used, the same light spot is formed on the side of the photodetector 10.

26. 发明专利

JPH10134487A DIGITAL DISK PLAYER 失效
公开(公告)号：JPH10134487A
公开(公告)日：1998-05-22
申请号：JP30358596
申请日：1996-10-29
申请人： ALPINE ELECTRONICS INC
发明人： YOKOTA HACHIRO
IPC分类号： H04N19/70 , G11B7/004 , G11B7/14 , G11B19/02 , G11B19/12 , H04N7/24 , H04N19/00 , H04N19/85 , G11B7/20
摘要： PROBLEM TO BE SOLVED: To provide the digital disk player capable of automatically discriminating whether a loaded disk is a single layer disk or a dual layer disk in a short time. SOLUTION: This DVD(digital video disk) player 1 is composed of an optical pickup 14, a focus error amplifier 18, a focus servo processor 20, a focus actuator driver 22, a focus zero-cross detecting part 24, a timer 26, a system controller 28 and an RF amplifier 40. An objective lens 14a is raised or lowered at a fixed speed, and when a focus zerocross signal corresponding to a signal recording surface of the 1st layer is outputted from a focus zero-cross detecting part 24, the timer 26 is started up. A mark signal for showing prescribed timing for likely obtaining a focus zero-cross signal corresponding to a signal recording surface of the 2nd layer is generated by the timer 26, and when the focus zero- cross signal in this timing is outputted, the disk 10 is judged to be the dual layer disk.

27. 发明专利

JPH10124914A OPTICAL DISK REPRODUCING DEVICE AND OPTICAL DISK REPRODUCING METHOD 失效
公开(公告)号：JPH10124914A
公开(公告)日：1998-05-15
申请号：JP27056396
申请日：1996-10-14
申请人： HITACHI LTD
发明人： NAKAJIMA JUNJI , TAKEUCHI TOSHIFUMI , ENDO HIROSHI , AZUMA JIRO , NISHIMURA KOICHIRO , HIROSE KOICHI
IPC分类号： G11B7/135 , G11B7/20
摘要： PROBLEM TO BE SOLVED: To reproduce various kinds of optical disks by automatically setting a light source, a photodetector and a tracking error generating system used to obtain a best reproducing signal according to the kind of a loaded optical disk. SOLUTION: Luminous fluxes from semiconductor lasers (LDs) 3 and 4 having different oscillation wavelengths are projected to an optical disk via optical systems and photodetectors 7 and 8 output signals according to its reflected light quantities. Based on these signals, a microcomputer 35 determines the kind of the optical disk, switches changeover switches 12 and 33 and selects one of two means for generating tracking error signals. Thus, the LD 3 and 4 used for reproducing the optical disk, the gain of a reproducing system and a tracking control system are set to values most suitable for the reproduction of the optical disk. Thus, the increase of a circuit quantity is suppressed to a minimum and various kinds of optical disks are reproduced.

28. 发明专利

JPH1074332A OPTICAL REPRODUCING DEVICE 失效
公开(公告)号：JPH1074332A
公开(公告)日：1998-03-17
申请号：JP23082896
申请日：1996-08-30
申请人： SANYO ELECTRIC CO
发明人： KAJIYAMA SEIJI , TSUCHIYA YOICHI
IPC分类号： G02F1/13 , G02F1/133 , G11B7/13 , G11B7/135 , G11B7/20
摘要： PROBLEM TO BE SOLVED: To interchange and reproduce plural optical disks, whose substrates are different in thickness, by using an optical pickup of simple constitution. SOLUTION: A collimeter lens 5, in which a twisted negative (TN) type liquid crystal 5b is inserted between two glasses 5a, is applied to the optical pickup 10. Then, the refractive index distribution of the collimeter lens 5 is set to 1.5/1.5/1.5 along the transmitting direction of a laser beam without applying the voltage to the TN type liquid crystal 5b when a thin film type optical disk with the substrate 77 of 0.6 mm in thickness is reproduced. The refractive index distribution of the collimeter lens 5 is set to 1.5/1.65/1.5 along the transmitting direction of the laser beam by applying the voltage to the TN type liquid crystal 5b when the thin film type optical disk with the substrate 77 having a standard thickness of 1.2 mm is reproduced.

29. 发明专利

JPH09297936A OPTICAL PICKUP DEVICE 失效
公开(公告)号：JPH09297936A
公开(公告)日：1997-11-18
申请号：JP13750696
申请日：1996-05-08
申请人： MINEBEA CO LTD
发明人： OHASHI KENJI , KAYANO KAZUNORI , KITAMURA ATSUSHI
IPC分类号： G11B7/135 , G11B7/20
摘要： PROBLEM TO BE SOLVED: To enable the recording and reproduction of an optical disk having different frequency with one optical pickup device by reading out a signal with one optical lens system from an optical disk in which signal are recorded with two kinds of recording wavelengths, making optical axes of semiconductor laser beams having different wavelengths coincident, and combining P polarization and S polarization in a plane of polarization. SOLUTION: A first wavelength laser beam 7A transmits a polarization beam splitter 5 having a polarization angle extending straightly to an optical disk recording layer, a second wavelength laser beam 7B is fully reflected at a transmission surface of the first wavelength laser beam 7A, passed through the same light path as the first laser beam 7A, converged and image-formed on an optical disk recording surface 1B by an object lens. A reflected laser beam of the optical disk recording layer is reflected by a beam splitter 4, and converged and image-formed on a first light receiver 6A. In a polarization beam splitter 5, the leakage of laser beams from two kinds of semiconductor laser is received by a second light receiver, after converted to an electric signal, it is compared with a set value of an optical output setter, fed back to the first or second semiconductor laser, then, an auto power control circuit is constituted.

30. 发明专利

JP2656847B2 失效
公开(公告)号：JP2656847B2
公开(公告)日：1997-09-24
申请号：JP19287190
申请日：1990-07-23
申请人： KYANON KK
发明人： HOSHI HIROAKI , MORISHIMA HIDEKI , YAMAMOTO MASAKUNI , YAMAGUCHI EIJI , MATSUMURA SUSUMU
IPC分类号： G11B7/00 , G11B7/004 , G11B7/005 , G11B7/20 , G11B7/24

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