Source: http://www.google.com/patents/US5809000?dq=6246862
Timestamp: 2013-12-11 06:42:21
Document Index: 425673778

Matched Legal Cases: ['arts 232', 'arts 232', 'art 232', 'art 232', 'art 232', 'art 234', 'art 234', 'art 234', 'art 234']

Patent US5809000 - Optical pickup system for reading optical disks of different thicknesses - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Advanced Patent Search | Sign inAdvanced Patent SearchPatentsAn optical pickup system for reading information stored on a first or a second optical disk, each of the optical disks having a different thickness and selectively loaded on a disk tray, is provided with a light source for generating a first or a second light beam depending on the optical disk selectively...http://www.google.com/patents/US5809000?utm_source=gb-gplus-sharePatent US5809000 - Optical pickup system for reading optical disks of different thicknessesPublication numberUS5809000 APublication typeGrantApplication numberUS 08/866,233Publication dateSep 15, 1998Filing dateMay 30, 1997Priority dateMay 31, 1996Fee statusLapsedAlso published asCN1170931APublication number08866233, 866233, US 5809000 A, US 5809000A, US-A-5809000, US5809000 A, US5809000AInventorsYang-Oh ChoiOriginal AssigneeDaewoo Electronics, Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (3), Referenced by (22), Classifications (25), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetOptical pickup system for reading optical disks of different thicknessesUS 5809000 AAbstract An optical pickup system for reading information stored on a first or a second optical disk, each of the optical disks having a different thickness and selectively loaded on a disk tray, is provided with a light source for generating a first or a second light beam depending on the optical disk selectively loaded, each of the first and the second light beams having a different wavelength from each other, λ.sub.1, λ.sub.2, a knife edge, an optical device including a first and a second parts, an objective lens and a detector. In the above system, if one of the optical disks is selected to be loaded on a disk tray, the light source selects a light beam from the first and the second light beams based on the thickness of the selected optical disk. The knife edge reflects a portion of the selected light beam to the corresponding part of the optical device and the objective lens focuses the portion of the selected light beam transmitted through the selected optical disk, wherein the corresponding part of the optical device is capable of transmitting the selected light beam. The light beam reflected from the selected optical disk is converged on the detector and the corresponding part of the optical device, thereby allowing the optical pickup system to read the information off the selectively loaded optical disk.
What is claimed is: 1. An optical pickup system for reading information stored on a first or a second optical disk being selectively loaded on a disk tray, each of the optical disks having a recording surface and a different thickness, the optical pickup system comprising:a light source for selectively generating a first or a second light beam, each of the light beams having a different wavelength from each other; means for reflecting a portion of the selectively generated light beam toward the recording surface of the selectively loaded optical disk; means for transmitting a fraction of the reflected light beam toward the recording surface of the selectively loaded optical disk; and means for focusing the transmitted light beam on the recording surface of the selectively loaded optical disk, thereby allowing for the optical pickup system to read the information off the recording surface. 2. The optical pickup system of claim 1, further comprising a detector, being placed opposite the optical disk with respect to the focusing means, provided with a plurality of reception surfaces, each of the reception surfaces being capable of measuring a light beam intensity and generating a corresponding output signal.
FIELD OF THE INVENTION The present invention relates to an optical pickup system; and, more particularly, to an improved optical pickup system capable of reading optical disks of different thicknesses.
DESCRIPTION OF THE PRIOR ART In FIG. 1, there is shown an optical pickup system 100 capable of reproducing a signal from an information storage area on a conventional optical information recording disk, disclosed in commonly owned, U.S. Pat. No. 5,568,462, entitled "KNIFE EDGE METHOD FOR USE IN DETECTING A FOCUSING ERROR IN AN OPTICAL PICKUP SYSTEM", which is incorporated herein by reference. The optical pickup system 100 comprises a light source 112, an objective lens 116, an optical disk 119, a knife edge 120 having a reflection surface 134, a differential amplifier 128 and an optical detector 122 provided with a reception surface 127. In the system 100, a light beam 113 emitted from the light source 112 impinges onto the knife edge 120 and is partially reflected by a reflection surface 134 thereof. The reflected light beam 115 from the reflection surface 134 is transmitted through the objective lens 116 onto a recording surface 118 of the optical disk 119 as a focused light beam. The focused light beam is then converged by the objective lens 116 and then passing by the knife edge 120. The focused light beam passed by the knife edge 120 impinges on the reception surface 127 of the optical detector, the reception surface 127 including a first and a second photoelectric cells 132, 133. Outputs from the first and the second photoelectric cells 132, 133 are sent to a pair of input ports 124, 126 on the differential amplifier 128 which generates a focusing error signal by comparing the outputs from the first and the second photoelectric cells of the optical detector.
SUMMARY OF THE INVENTION It is, therefore, a primary object of the present invention to provide an improved optical pickup system capable of reading optical disks having different thicknesses from each other.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS There are illustrated in FIGS. 2 to 6 various views of the inventive optical pickup system in accordance with a preferred embodiment of the present invention.
As shown in FIG. 2, the optical pickup system 200 in accordance with the present invention comprises a light source 210, e.g., a wavelength-tunable semiconductor laser, for generating a first or a second light beam, selectively, each of the first and the second light beams having a different wavelength from each other, a first wavelength λ.sub.1, and a second wavelength λ.sub.2, a diffraction grating 270, a knife edge 220 provided with a reflection surface 222, an optical device 230 including a first and a second parts 232, 234, an objective lens 240 and a detector 260 provided with a plurality of reception surfaces 262, 264.
In reproducing an information signal recorded on the recording surface 254 of the thin optical disk 252, the light source 210 generates the first light beam, having the first wavelength λ.sub.1 shown in FIG. 3, wherein the solid line represents an optical path of the three diffractive components of the first light beam emitted from the light source 210. In this case, the optical device 230 includes a first and a second parts 232, 234, wherein the first part 232 is in the form of an annular disk. The first part 232 transmits the three diffractive components of the first light beam having the first wavelength λ.sub.1 to the objective lens 240 and reflects the other light beams having different wavelengths. The objective lens 240 includes a first and a second divisions 242, 244, wherein the numerical aperture of the first division 242 is larger than that of the second division 244. Further, the first division 242 of the objective lens 240 is designed for focusing the light beam impinging thereon onto the recording surface 254 of the thin optical disk 252. The three diffractive components of the light beam transmitted through the first part 232 are focused on the recording surface 254 of the optical disk 252 through the first division 242 of the objective lens 240. The first division 242 of the objective lens 240 converges the light beam reflected from the recording surface 254 on the detector 260 by passing by the reflection surface 222 of the knife edge 220.
On the other hand, in reproducing an information signal recorded on the recording surface 258 of the thick, e.g., 1.2 mm, optical disk 256, the light source 210 generates the second light beam, having the second wavelength λ.sub.2 shown in FIG. 5, wherein the solid line represents an optical path of the three diffractive components of the second light beam emitted from the light source 210. In this case, the second part 234 of the optical device 230 transmits the three diffractive components of the second light beam having the second wavelength λ.sub.2 to the objective lens 240 and reflects the other light beams having different wavelengths. The light beam transmitted through the second part 234 of the optical device 230 impinges onto the second division 244 of the objective lens 240. Further, the second division 244 of the objective lens 240 is designed to focus the light beam impinging thereon onto the recording surface 258 of the thick optical disk 256. The three diffractive components of the second light beam transmitted through the second part 234 are focused on the recording surface 258 of the thick optical disk 256 by the second division 244 of the objective lens 240. The second division 244 of the objective lens 240 converges the light beam reflected from the recording surface 258 on the detector 260 after being transmitted through the second part 234 of the optical device 230 and bypassing the reflection surface 222 of the knife edge 220.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5568462 *Nov 15, 1994Oct 22, 1996Daewoo Electronics Co., Ltd.Knife edge method for use in detecting a focussing error in an optical pickup systemUS5665957 *May 1, 1996Sep 9, 1997Samsung Electronics Co., Ltd.Lens device comprising light blocking means and an optical pickup apparatus using the lens deviceUS5696750 *Jun 5, 1996Dec 9, 1997Nec CorporationOptical head apparatus for different types of disks* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS5974020 *Oct 8, 1997Oct 26, 1999Industrial Technology Research InstituteTwo-wavelength laser pick-up head for a DVDUS5991255 *Oct 27, 1997Nov 23, 1999Nec CorporationOptical head using a light blocking device to lower the numerical aperture of an incident beamUS6064529 *Jul 2, 1998May 16, 2000Optiteck, Inc.Spherical aberration correction using flying lens and methodUS6163415 *Apr 2, 1999Dec 19, 2000Siros Technologies, Inc.Loading and unloading a flying lensUS6215756 *Mar 13, 1998Apr 10, 2001Hitachi, Ltd.Optical head having two lasers of different wavelength and an objective lens made of one material having a rectangular groove shifting phase to decrease focused laser beam spot aberration for focusing laser beams on different thickness substratesUS6256284 *Feb 10, 2000Jul 3, 2001Hitachi, Ltd.Optical head having two semiconductor lasers of different wavelength, an objective lens focusing laser beams on different thickness substrates, and an annular phase shifter decreasing focused laser beam spot abberationUS6259668Dec 21, 1999Jul 10, 2001Samsung Electronics Co., Ltd.Recording/reproducing apparatus having an optical pickup device to read from and record information to disks of different thicknessesUS6333908Jan 25, 2001Dec 25, 2001Hitachi, Ltd.Optical head having two semiconductor lasers of different wavelength, an objective lens focusing laser beams on different thickness substrates, and an annular phase shifter decreasing focused laser beam spot aberrationUS6342976 *Jan 14, 2000Jan 29, 2002Fuji Photo Optical Co., Ltd.Luminous flux diameter variable type objective lens and optical apparatus using the sameUS6430140Sep 6, 2001Aug 6, 2002Hitachi, Ltd.Optical head having two semiconductor lasers of different wavelength, an objective lens focusing laser beams on different thickness substrates, and an annular phase shifter decreasing focused laser beam spot aberrationUS6449237Oct 22, 1999Sep 10, 2002Samsung Electronics Co., Ltd.Optical recording and pickup head for digital versatile disc compatible with read-writable compact disc by adopting flat plate lens having staircase type diffraction grating structureUS6493307Mar 4, 2002Dec 10, 2002Hitachi, Ltd.Optical head having two semiconductor lasers of different wavelength, an objective lens focusing laser beams on different thickness substrates, and an annular phase shifter decreasing focused laser beam spot aberrationUS6649893 *Apr 12, 2001Nov 18, 2003Olympus Optical Co., Ltd.Focus detecting device for an optical apparatusUS6765857Jun 25, 2002Jul 20, 2004Samsung Electronics Co., Ltd.Optical recording and pickup head for digital versatile disc compatible with read-writable compact disc by adopting flat plate lens having staircase type diffraction grating structureUS6882614Feb 22, 2001Apr 19, 2005Samsung Electronics Co., Ltd.Recording/reproducing apparatus having an optical pickup device to read from and record information to disks of different thicknessesUS7016291Jun 17, 2004Mar 21, 2006Samsung Electronics Co., Ltd.Optical recording and pickup head for digital versatile disc compatible with read-writable compact disc by adopting flat plate lens having staircase type diffraction grating structureUS7283452Jan 31, 2003Oct 16, 2007Asahi Glass Company, LimitedObjective lens having two aspheric surfaces and a phase shifter and optical device including the sameUS7406756 *Oct 21, 2004Aug 5, 2008Seiko Epson CorporationMethod for manufacturing a piezoelectric resonatorUS8503272Aug 22, 2002Aug 6, 2013Samsung Electronics Co., Ltd.Recording/reproducing apparatus having an optical pickup device to read from and record information to disks of different thicknessesEP0996121A2 *Oct 22, 1999Apr 26, 2000Samsung Electronics Co., Ltd.Optical recording and pickup head for digital versatile discEP1001414A2 *Oct 21, 1999May 17, 2000Samsung Electronics Co., Ltd.Compatible optical pickupEP1315011A1 *Jul 31, 2001May 28, 2003Asahi Glass Company Ltd.Objective lens and optical device* Cited by examinerClassifications U.S. Classification369/112.5, 369/118, 369/112.29, 369/112.26, 369/44.24, G9B/7.12, G9B/7.103, G9B/7.102, 369/94, 369/44.23International ClassificationG11B7/135, G11B7/125, G11B7/20, G11B7/00Cooperative ClassificationG11B7/1374, G11B7/1275, G11B7/1381, G11B7/1353, G11B7/0916, G11B2007/0006European ClassificationG11B7/1275, G11B7/1381, G11B7/1374, G11B7/09B6, G11B7/1353Legal EventsDateCodeEventDescriptionNov 12, 2002FPExpired due to failure to pay maintenance feeEffective date: 20020915Sep 16, 2002LAPSLapse for failure to pay maintenance feesApr 2, 2002REMIMaintenance fee reminder mailedMay 30, 1997ASAssignmentOwner name: DAEWOO ELECTRONICS CO., LTD., KOREA, REPUBLIC OFFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:CHOI, YANG-OH;REEL/FRAME:008593/0543Effective date: 19970522May 30, 1997AS02Assignment of assignor's interestOwner name: CHOI, YANG-OHOwner name: DAEWOO ELECTRONICS CO., LTD. JUNG-GU 541, 5-GA, NAEffective date: 19970522RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google