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31. 发明专利

JP2001209967A OPTICAL HEAD, AND OPTICAL INFORMATION RECORDING/ REPRODUCING DEVICE USING THE SAME 失效
公开(公告)号：JP2001209967A
公开(公告)日：2001-08-03
申请号：JP2000018005
申请日：2000-01-25
申请人： HITACHI LTD
发明人： NAKAO TAKESHI , ONISHI KUNIKAZU
IPC分类号： G11B7/135 , G11B7/20
摘要： PROBLEM TO BE SOLVED: To provide a small sized DVD/CD interchangeable optical head on which two laser beam sources different in wavelength are mounted. SOLUTION: A means for synthesizing an optical path of a luminous flux emitted from two light sources is arranged in the optical path between two laser beam sources oscillating with different wavelengths and a collimator lens reducing the divergence angle of the luminous flux exited from two light sources, and also auxiliary optical systems which reduce the divergence angles of the luminous flux emitted from respective light sources into the prescribed angles respectively are arranged in the optical path between the optical path synthesizing means and two light sources.

32. 发明专利

JP2000357341A DIFFRACTION ELEMENT AND OPTICAL PICKUP DEVICE MOUNTING THE SAME 失效
公开(公告)号：JP2000357341A
公开(公告)日：2000-12-26
申请号：JP16631799
申请日：1999-06-14
申请人： HITACHI LTD
发明人： ONISHI KUNIKAZU , IZUMI KATSUHIKO , NAKAO TAKESHI
IPC分类号： G11B7/135
摘要： PROBLEM TO BE SOLVED: To provide an optical pickup device having drastically simplified constitution by making the detecting system common between a DVD system and a CD system in a DVD/CD interchangeable one objective lens optical pickup device which uses a DVD exclusive objective lens. SOLUTION: For example, DVD reproduced light (0-order light) which transmits the diffraction element 14 as it is and +1-order diffracted light of CD reproduced light which is diffracted and separated by the diffraction element 14 are made incident to a common photodetector 9 by disposing the diffraction element 14 having lens function in an optical path of the optical pickup device. In such a manner, by selectively guiding ±1-order diffracted light or 0-order light of DVD reproduced light and CD reproduced light into the common photodetector 9, the common use of the detecting system is achieved.

33. 发明专利

JP2000003523A OPTICAL PICKUP AND OPTICAL DISK DEVICE 失效
公开(公告)号：JP2000003523A
公开(公告)日：2000-01-07
申请号：JP16466098
申请日：1998-06-12
申请人： HITACHI LTD , HITACHI MEDIA ELECTRON KK
发明人： ONISHI KUNIKAZU , OTA MITSUHIKO , SUGI YASUYUKI , FUJITA SHINJI , SUGIYAMA TOSHIO , FUKUI YUKIO
IPC分类号： G11B7/09 , G11B7/135
摘要： PROBLEM TO BE SOLVED: To obtain a photodetector in which signal lines are made equal to or smaller than a specified number of lines by setting the photodetector so that luminous fluxes of one pair and luminous of another pair being in zeroth- order luminous fluxes and ±1st-order luminous fluxes which are respectively divided into two luminous fluxes are respectively focused in the front and the back of the photodetector and providing first to sixth light receiving photodetecting areas in the photodetector. SOLUTION: Spots L10, L20 and M10, M20 by main luminous fluxes and spots L11, L21, L22 and M12, M21, M22 by subluminous fluxes of respective two diffracted lights are set so as to be projected on the photodetector 7. Photodetecting areas 710, 720, 711, 721, 712, 722 being the detection surface of the photodetector 7 are respectively divided into a to d, e to h, i to m, n to q, r to v and w to z in photodetecting parts 70. An information recorded signal is detected by L10, L20 or M10, M20 and a focus error signal is detected by using two subluminous fluxes. Thus, a reproduction or a recording is made possible with signal output lines equal to or smaller than 9 lines by respectively using an optimum tracking error signal detecting means and an optimum wavelength.

34. 发明专利

JPH11296875A OPTICAL HEAD AND OPTICAL DISK DEVICE 失效
公开(公告)号：JPH11296875A
公开(公告)日：1999-10-29
申请号：JP3097199
申请日：1999-02-09
申请人： HITACHI LTD
发明人： SHIMANO TAKESHI , NAKAMURA SHIGERU , ONISHI KUNIKAZU , INOUE MASAYUKI , FUKUI YUKIO
IPC分类号： G11B7/09 , G11B7/135
摘要： PROBLEM TO BE SOLVED: To eliminate external disturbances generated in an out-of-focus signal when an optical spot crosses a track on a recording film following the eccentricity of an optical disk, and to cancel the offset of a tracking error signal following a lens movement. SOLUTION: The wave front phase of ± first order diffracted light is shifted by λ/2 at a cycle Dl/(2P.NA) by a phase inversion diffracted grating 701, the phase thereof being inverted in the radial direction of an optical disk at a cycle Dλ/(2P.NA), and a sub-spot is arranged on the same track as that of a main spot. By adding together the out-of-focus error signals of the main and sub-spots based on a proper gain ratio, external disturbances generated in the out-of-focus error signal are canceled. By subtracting tracking error signals from each other by the push-pull system of the main and sub-spots based on a proper gain ratio, offset thereof is canceled.

35. 发明专利

JPH11250473A OPTICAL PICKUP AND OPTICAL DISK DEVICE 失效
公开(公告)号：JPH11250473A
公开(公告)日：1999-09-17
申请号：JP5366998
申请日：1998-03-05
申请人： HITACHI LTD
发明人： OTA MITSUHIKO , ONISHI KUNIKAZU , INOUE MASAYUKI , SASAKI TORU , FUKUI YUKIO
IPC分类号： G11B7/09
摘要： PROBLEM TO BE SOLVED: To miniaturize an optical pickup to obtain a focus error signal using a prism by a spot size method, to reduce the number of parts, and to simplify constitution of a prism. SOLUTION: A prism 3 used for an optical pickup is set so that when luminous flux is focused on an optical disk 5, luminous flux transmitting a semi- transmission reflecting surface is made incident on a first light detector 22 at a point in front of a focus point, luminous flux reflected by the reflecting surface is made incident on a second light detector 21 at a point far from the focus point. And the first and the second light detectors 21, 22 are divided into five or eight.

36. 发明专利

JPH10233036A POLARIZING OPTICAL ELEMENT AND OPTICAL HEAD DEVICE 失效
公开(公告)号：JPH10233036A
公开(公告)日：1998-09-02
申请号：JP3590997
申请日：1997-02-20
申请人： HITACHI LTD
发明人： ONISHI KUNIKAZU , INOUE MASAYUKI , FUKUI YUKIO , SUGI YASUYUKI , SHINOHARA HIDENORI , FUJITA SHINJI , IMADA RITSUO
IPC分类号： G11B7/14
摘要： PROBLEM TO BE SOLVED: To provide the optical head device with a high function capable of reproducing plural kinds of optical disks having their different substrates in thickness, although this optical head device is nevertheless miniaturized, simplified and equipped with one objective lens and one or plural optical module(s). SOLUTION: The polarizing optical element 9 consisting of a discoid transmissive area provided in a central part and a diffraction grating area having polarizing anisotropy provided on the outer side of this transmissive area and a 1/4- wavelength plate 10 are disposed in an optical path. At the time of reproducing the CD(compact disk) 11, a beam is restricted in its diameter in order to become a prescribed numerical aperture by virtue of this polarizing optical element 9 and is incident upon an objective lens 5 for the DVD(digital video disk) 6. As a result, a good convergent spot is formed on a recording surface of the CD 11 by using even this objective lens for the DVD 6. On the other hand, return light reflected by the disk is transmitted as it is through the polarizing optical element 9 because its polarizing direction is turned at 90 deg. by the 1/4-wavelength plate 10. Consequently, the CD can satisfactorily be reproduced without shading of the return light beam attending upon displacement of the objective lens.

37. 发明专利

JPH103673A OPTICAL HEAD, OPTICAL DISK DEVICE AND OPTICAL DISK REPRODUCING METHOD 失效
公开(公告)号：JPH103673A
公开(公告)日：1998-01-06
申请号：JP15367496
申请日：1996-06-14
申请人： HITACHI LTD
发明人： ONISHI KUNIKAZU , INOUE MASAYUKI , FUKUI MASAKAZU
IPC分类号： G11B7/09 , G11B7/135
摘要： PROBLEM TO BE SOLVED: To always perform a satisfactory focusing control and a satisfactory tracking control even when the kind of an optical disk is changed in an optical disk device capable of coping with plural kinds of optical disks by using one set of an optical head. SOLUTION: The arrangement intervals in a disk direction of three converged spots (100-102) to be formed on an optical disk are made so as to become half a track pitch with respect to a first optical disk 9a and so as to become the odd numbered multiple of one-fourth a track pitch and more than three-fourth the track pitch with respect to a second optical disk 9b, respectively. Concretely, the focal length of an objective lens and the grating constant of a diffraction grating in an optical head are set so as to satisfy a prescribed relational expression. Moreover, a differential push-pull system or a three beam system is used as a tracking control system and the systems are properly changed over in accordance with kinds of disks.

38. 发明专利

JPH09161293A OPTICAL DISK DEVICE 失效
公开(公告)号：JPH09161293A
公开(公告)日：1997-06-20
申请号：JP32474195
申请日：1995-12-13
申请人： HITACHI LTD
发明人： ISHIBASHI TOSHIAKI , ONISHI KUNIKAZU , INOUE MASAYUKI , SUZUKI YOSHIO
IPC分类号： G11B7/09 , G11B7/095 , G11B7/125 , G11B7/135
摘要： PROBLEM TO BE SOLVED: To obtain a precise tilt error signal with simple constitution related to a tilt detecting optical pickup in an optical disk reproducing device. SOLUTION: A diffraction grating 111 carving a grating groove pattern 114 capable of adding a coma aberration component 14 to ±first-order diffracted light and a photodetector 101 light receiving the diffracted light are provided in an optical path between a laser diode 110 becoming a reproducing light source and an optical disk 100, and the tilt error signal is generated through a signal processing circuit capable of operating an intensity difference between respective light receiving intensity. By deforming the grating groove pattern 114, the arrangement of the coma aberration is varied. Further, the tilt error signal is obtained from a difference of the number of bit errors in a regenerative signal from the diffracted light having the coma aberration. By adding the coma aberration component to the diffracted light, the matter that the sensitivity of the tile error signal for a tilt angle is enhanced easily becomes possible.

39. 发明专利

JPH07307025A OPTICAL DISK AND SIGNAL REPRODUCING DEVICE THEREFOR 失效
公开(公告)号：JPH07307025A
公开(公告)日：1995-11-21
申请号：JP9867694
申请日：1994-05-12
申请人： HITACHI LTD
发明人： NAKAJIMA JUNJI , SUZUKI YOSHIO , ONISHI KUNIKAZU , INOUE MASAYUKI , SASAKI TORU
IPC分类号： G11B7/24 , G11B7/00 , G11B7/005 , G11B7/007 , G11B7/09
摘要： PURPOSE:To set a semiconductor laser output power where the ratio of an amplitude value to the peak value of the reproduced signals is maximum as an optimum value by providing a power setting area consisting of a prescribed pit array on an optical disk. CONSTITUTION:The optical disk 100 is provided with a light control layer consisting of chalcogenide, etc., on the surface of a transparent substrate formed with phase pits. Window and mask sections having different reflectivities are generated in the irradiated area by irradiating the area with light spot. A divider circuit 12 calculates (amplitude detection value 304) divided by (peak detection value 305) = (divided value 307) for a reproduced signal 301 from an optical disk 100 and transmits the value to a controlled 17. The controller 17 moves an optical head 1 to a power setting area of the disk 100 at the time of the start of a reproducing operation, increases an output power P0 of a semiconductor laser 2 stepwise and obtains an output power Pr1 when the value 307 becomes a maximum. Thus, the optimum area ratio between the window section and the mask section is set.

40. 发明专利

JPH0620291A OPTICAL INFORMATION RECORDER/REPRODUCER 失效
公开(公告)号：JPH0620291A
公开(公告)日：1994-01-28
申请号：JP11720392
申请日：1992-05-11
申请人： HITACHI LTD
发明人： ONISHI KUNIKAZU , SASAKI TORU , INOUE MASAYUKI , SUZUKI MOTOYUKI , SUZUKI YOSHIO , MIURA MICHIO , SAITO AKIRA , SHIGEMATSU KAZUO , KITADA YASUO
IPC分类号： G11B7/085 , G11B7/09 , G11B7/135 , G11B21/08
摘要： PURPOSE:To make it possible to suppress offset of tracking error signal produced at the time of positional correction of light spot by shifting the departing position of light flux from a prism simultaneously with variation of deflecting angle thereof through rotation of a wedge type prism. CONSTITUTION:A wedge type prism 140 is provided with an actuator 141 for rotating the prism 140 around Z axis on the drawing (normal to the surface of paper). Both first and second light spots 162, 172 are subjected to positional control for the distortion component of an optical disc 1 through positional control of an objective lens 110. Relative positional shift of two light spots, caused by adjustment or temperature, is corrected by feeding tracking error signals obtained from a second optical detector 127 and a subtracking error detecting circuit 7 back to the actuator 141 and rotating the prism 140 thereby varying the deflection angle of light flux 170 impinging on the lens 110.

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