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1. 发明专利

JP2000293933A OPTICAL DISK DRIVE 失效
公开(公告)号：JP2000293933A
公开(公告)日：2000-10-20
申请号：JP9983599
申请日：1999-04-07
申请人： HITACHI LTD , HITACHI MEDIA ELECTRON KK
发明人： HIROSE KOICHI , OTA MITSUHIKO , SUGIYAMA TOSHIO , SUGI YASUYUKI , FUJITA SHINJI , FUKUI YUKIO , ENDO HIROSHI
IPC分类号： G11B7/125 , G11B7/00 , G11B7/005 , G11B19/12
摘要： PROBLEM TO BE SOLVED: To reproduce plural kinds of optical disks whose reflectance is different without damaging the life of a light source nor a C/N ratio so much by switching outputs of the light source in accordance with the kind of a mounted optical disk, also switching the gains of a current/voltage conversion circuit and obtaining an RF signal with almost fixed amplitude. SOLUTION: A system control circuit 80 makes a laser drive circuit 81 switch outgoing beams of a light source 1 in accordance with the discriminated result of a mounted optical disk type from a disk type discriminating means 85. An RF signal outputted from an optical detector 2 is inputted to a binarization circuit 88 through a current/voltage conversion circuit 86 and a waveform equalizing circuit 87 and binarized. The circuit 80 outputs a control signal in accordance with the reflectance of an optical disk, changes the gain of the circuit 86 and controls the amplitude of an input signal of the circuit 88 to be almost constant. Thus, it is possible to mount an optical disk having plural reflectance without damaging the life of a laser diode nor a C/N ratio.

2. 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.

3. 发明专利

JPH10177741A OPTICAL HEAD AND OPTICAL DISK DEVICE 失效
公开(公告)号：JPH10177741A
公开(公告)日：1998-06-30
申请号：JP33399996
申请日：1996-12-13
申请人： HITACHI LTD , HITACHI MEDIA ELECTRON KK
发明人： FUJITA SHINJI , SHINOHARA HIDENORI , SUGIYAMA TOSHIO , IMADA RITSUO , FUKUI YUKIO
IPC分类号： G11B7/14 , G11B7/00 , G11B7/12 , G11B7/125 , G11B7/135
摘要： PROBLEM TO BE SOLVED: To provide a small-sized optical head which is also mountable at an optical disk device having a limitation on transverse and longitudinal directions and thickness direction relating to the optical disk device which executes recording and/or reproducing 22 kinds of the optical disks varying in corresponding wavelengths. SOLUTION: A dichroic mirror 6 or a polarization beam splitter is disposed as a light synthesizing and separating means between a mirror 4 and an objective lens 7, by which the arrangement of an optical system corresponding to the first disk and an optical system corresponding to the second disk are made into a two-layered structure and the adequate selection of the transverse and longitudinal directions and thickness direction of the optical head is made possible. As a result, the small-sized optical head which is hardly restricted by the size of the optical disk device is provided.

4. 发明专利

JP2003178482A PHOTODETECTOR, SIGNAL PROCESSING CIRCUIT, AND OPTICAL INFORMATION REPRODUCING DEVICE USING PHOTODETECTOR AND SIGNAL PROCESSING CIRCUIT 审中-公开
公开(公告)号：JP2003178482A
公开(公告)日：2003-06-27
申请号：JP2002331529
申请日：2002-11-15
申请人： HITACHI LTD , HITACHI MEDIA ELECTRON KK
发明人： ONISHI KUNIKAZU , SHIMANO TAKESHI , NAKAMURA SHIGERU , INOUE MASAYUKI , FUKUI YUKIO , SUGI YASUYUKI , FUJITA SHINJI , OTA MITSUHIKO
IPC分类号： G11B7/09 , G11B7/13
摘要： PROBLEM TO BE SOLVED: To dramatically reduce influence of disturbance experienced in detecting a defocusing signal by means of an astigmatism system in reproducing a DVD-RAM disk or the like, and to dramatically reduce influence of offset accompanied by object lens displacement experienced in detecting a tracking error signal by means of a push-pull system, and to realize an optical disk device having high general-purpose properties and complying with the reproduc tion of existing optical disks, including CD, CD-ROM, CD-R as well as high- density disks, including DVD-RAM, DVD-ROM disks by using a simple optical head. SOLUTION: Three optical beams separated by diffraction grating are irradiated at the optical disk at its prescribed position. A 12-split photodetector having a prescribed configuration is provided. Thereby a good defocusing signal and a tracking error signal are obtained and the optical disk device is realized, which has the high general-purpose properties and is capable of reproducing a signal in a plurality of optical disks having different recording densities and different disk configurations by using the simple optical head. COPYRIGHT: (C)2003,JPO

5. 发明专利

JP2003151162A OPTICAL DETECTOR, SIGNAL PROCESSING CIRCUIT AND OPTICAL INFORMATION REPRODUCTION APPARATUS USING THE SAME 审中-公开
公开(公告)号：JP2003151162A
公开(公告)日：2003-05-23
申请号：JP2002331530
申请日：2002-11-15
申请人： HITACHI LTD , HITACHI MEDIA ELECTRON KK
发明人： ONISHI KUNIKAZU , SHIMANO TAKESHI , NAKAMURA SHIGERU , INOUE MASAYUKI , FUKUI YUKIO , SUGI YASUYUKI , FUJITA SHINJI , OTA MITSUHIKO
IPC分类号： G11B7/09 , G11B7/13
摘要： PROBLEM TO BE SOLVED: To greatly reduce the effect of the disturbance that rises in detecting a focusing error signal by an astigmatic detection method in reproducing a DVD-RAM, etc., also to greatly reduce the effect of offset involved in the displacement of an objective lens, which rises in detecting a tracking error signal by a push-pull method and further to realize a versatile optical disk apparatus which responds even to the reproduction of a variety of high density optical disks, such as DVD-RAM and DVD-ROM disks, as well as conventional disks, such as CD, CD-ROM and CD-R disks by using a simple optical head. SOLUTION: This versatile optical disk apparatus obtains satisfactory focusing error signal and tracking error signal by being provided with an optical detector divided into twelve parts with a prescribed configuration, which irradiates a specified position of an optical disk with three optical beams separated by a diffraction grating, and can reproduce a signal from a plurality of optical disks with different recording density and disk configuration by using the simple optical head.

6. 发明专利

JP2002197713A OPTICAL HEAD AND OPTICAL DISK DEVICE USING IT 失效
公开(公告)号：JP2002197713A
公开(公告)日：2002-07-12
申请号：JP2000393261
申请日：2000-12-21
申请人： HITACHI LTD , HITACHI MEDIA ELECTRON KK
发明人： FUKUI MASAKAZU , FUJITA SHINJI , SHINODA IKUO , INUI MASAAKI , SUGI YASUYUKI , ISHIGAKI YASUHIRO , ONISHI KUNIKAZU
IPC分类号： G02B5/18 , G02B27/28 , G11B7/004 , G11B7/09 , G11B7/125 , G11B7/13 , G11B7/135
摘要： PROBLEM TO BE SOLVED: To provide an optical head and an optical disk device capable of coping with various optical disks different in disk thickness and recording material and also capable of performing stable and excellent recording/ reproducing to the optical disks different in track structure. SOLUTION: A diffraction grating having a cross type parting line is arranged among a first light source and a second light source which have different wavelengths respectively, an object lens for condensing a luminous flux radiated from the first light source and the second light source onto various optical disks different in disk thickness or the like and recording material, and a photodetector which receives reflected light from the optical disk and detects an electric signal. A reflected luminous flux from the optical disk is quadri-divided by the diffraction grating, diffracted light which is diffracted and separated in respective regions is guided to respective independent light receiving surface on the photodetector, and a tracking error signal by a detecting method in accordance with disk structure and a focus error signal by a knife edge system are detected.

7. 发明专利

JP2000082226A PHOTO-DETECTOR AND SIGNAL PROCESSING CIRCUIT, AND OPTICAL INFORMATION REPRODUCING DEVICE USING THE SAME 失效
公开(公告)号：JP2000082226A
公开(公告)日：2000-03-21
申请号：JP17184499
申请日：1999-06-18
申请人： HITACHI LTD , HITACHI MEDIA ELECTRON KK
发明人： ONISHI KUNIKAZU , SHIMANO TAKESHI , NAKAMURA SHIGERU , INOUE MASAYUKI , FUKUI YUKIO , SUGI YASUYUKI , FUJITA SHINJI , OTA MITSUHIKO
IPC分类号： G11B7/09 , G11B7/13
摘要： PROBLEM TO BE SOLVED: To largely reduce an offset by reducing the number of those signal lines to at least the predetermined number of lines or less, which connect predetermined signal lines transmitting photo-electrically converted signals obtained from light-receiving surfaces divided into predetermined pieces and transmit the photo-electrically converted signals from the photo-detectors to a signal processing circuit. SOLUTION: On both sides of a quadripertite light-receiving area 200 consisting of split light-receiving surfaces a-d, a quadripertite light-receiving area 201 consisting of e-h adjacently and a quadripertite light-receiving area 202 of i-1 are arranged. Detected currents photo-electrically converted by the light-receiving surfaces are converted by current-to-voltage converters 40-43, and a, b, d, e+i, g+k, and h+1 are outputted to eight output terminals of the photo-detector 9. Light spot signals of (a+b) and (c+d) which have subtracted tracking error signals from light spots of (a+b)-(c+d)}-K 2(amplification factor of amplifiers 61, 62). (e+f+i+j)-(h+g+l+k)} are obtained from the eight detected signals through adders 48-55 and substacters 70-72.

8. 发明专利

JPH09167377A OPTICAL DISK DEVICE AND OPTICAL HEAD USED THEREIN 失效
公开(公告)号：JPH09167377A
公开(公告)日：1997-06-24
申请号：JP32681295
申请日：1995-12-15
申请人： HITACHI LTD , HITACHI MEDIA ELECTRON KK
发明人： SUGI YASUYUKI , SUGIYAMA TOSHIO , IMADA RITSUO , FUKUI YUKIO , SHINOHARA HIDENORI , FUJITA SHINJI
IPC分类号： G11B7/09 , G11B7/135
摘要： PROBLEM TO BE SOLVED: To provide an optical disk device without having any deteriorated detecting signals by attaching a diagram preventing the vignetting of a reflected light from an optical information recording medium or limiting its vignetting amount within an allowable range even when the objective lens is decentered. SOLUTION: A light from a laser 1 is made a parallel light by a collimator lens, a light flux diameter is decided by a diagram 4 so as to decide the numeral aperture of objective lens, the light is passed through a half mirror 9 and a concave lens 3 and converged on the recording surface 8 of a compact disk 6 by an objective lens 5. A reflected light from the disk is reflected by the half mirror 9 and converged on a photodiode 11. For recording/reproducing of a high density recording medium, the concave lens 3 and the diaphragm 4 are removed from an optical path. By preventing the reflected light from passing through the diaphragm 4, the vignetting of the reflected light from the disk is prevented and thereby, the optical disk device having no detecting deterioration and having a simple mechanism can be provided.

9. 发明专利

JPH09180237A OPTICAL DISK DEVICE AND OPTICAL HEAD THEREFOR 失效
公开(公告)号：JPH09180237A
公开(公告)日：1997-07-11
申请号：JP33642795
申请日：1995-12-25
申请人： HITACHI LTD , HITACHI MEDIA ELECTRON KK
发明人： FUJITA SHINJI , SUGI YASUYUKI , SUGIYAMA TOSHIO , IMADA RITSUO , FUKUI YUKIO , SHINOHARA HIDENORI
IPC分类号： G11B7/135
摘要： PROBLEM TO BE SOLVED: To prevent detection signal from being deteriorated by vignetting of reflected light from a disk by a simple mechanism, with respect to an optical disk device and an optical head used therefor which record or reproduce onto or from two or more different kinds of optical disks by a system that reduces aberration of light spot by means of inserting and extraction an interchangeable lens. SOLUTION: A mechanism is provided to insert and extract an interchangeable lens 4 and an annular polarizing plate 5 in one body based on a judgment by a disk discriminating means. In the state where the interchangeable lens 4 is inserted, p-polarized incident light emitted from a light emitting element 1 cannot pass through the annular polarizing plate 5, and a prescribed numerical aperture is decided by a hole provided. On the other hand, even though a reflected light beam from a disk 10 is deviated from the incident light due to eccentricity of an objective lens 8, the reflected light can pass through the annular polarizing plate 5 while the beam is changed in its polarizing direction to be made s-polarized light through a quarter wave length plate 6.

10. 发明专利

JPH10222853A OPTICAL PICKUP AND OPTICAL DISK DEVICE 失效
公开(公告)号：JPH10222853A
公开(公告)日：1998-08-21
申请号：JP2046097
申请日：1997-02-03
申请人： HITACHI LTD , HITACHI MEDIA ELECTRON KK
发明人： OTA MITSUHIKO , IMADA RITSUO , FUJITA SHINJI , SUGIYAMA TOSHIO , FUKUI YUKIO
IPC分类号： G11B7/09 , G11B7/135
摘要： PROBLEM TO BE SOLVED: To make possible sharedly reproducing or recording plural kinds of optical disks by returning reflection light from the optical disk to a photo-detector in the vicinity of a light source with a diffraction grating, reproducing or recording plural kinds of optical disks. SOLUTION: A first diffractive grating 23 for separating light from a light source 1 to main luminous flux and two sub-luminous fluxes and a second diffractive grating 22 for guiding to a photodetector are formed on an optical element block 2, and the second diffraction grating 22 is separated to four areas, and the photodetector 3 is constituted so that a photodetecting part so as to be able to detect a recording/reproducing signal, a focus error signal using a spot size method, a tracking error signal using a phase difference method, the tracking error signal using a three spots method and the tracking error signal using a differential push-pull method is arranged. Three tracking error signal detecting methods are switched to a signal processing circuit suited to kinds of respective disks by a system control circuit based on a discriminate result of a disk kind discriminant to be executed.

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