With Detail, Configuration, Or Adjunct Of Element Having Slit Or Aperture In Radiation Path Patents (Class 369/118)
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Patent number: 6278679Abstract: The invention provides a near-field photochromic device for a supra-density optical memory, comprising a scanner carrying a data storage medium, an optical head having a tip, to be used for recording, readout and erasing, and located in close proximity to the data storage medium, and at least two lasers, alternatingly optically alignable with the optical head, wherein the data storage medium is a film consisting of a photochromic compound and wherein the distance between the tip and the data storage medium is within the limits of the near field of the optical head.Type: GrantFiled: August 5, 1997Date of Patent: August 21, 2001Assignee: Elop Eletro-Optics Industries Ltd.Inventors: Victor Weiss, Erez Hasman, Moshe Oron
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Publication number: 20010014061Abstract: There is provided an optical reproduction apparatus and an optical recording and reproduction apparatus which can improve a CNR and can read at high speed. The center portion of a laser light emitted from a semiconductor laser is shaded by a light shading portion of a first light shade, and its peripheral portion is condensed and irradiates a super-resolution film of an optical disk. The center portion of a reflected light from the optical disk is mainly made of a signal component, and a noise component almost disappears. Thus, the reflected light from the optical disk is separated into the center portion and its peripheral portion, and the reflected light made of the signal component of the center portion is used for signal reproduction, so that the CNR can be increased.Type: ApplicationFiled: January 30, 2001Publication date: August 16, 2001Applicant: FUJI XEROX CO., LTDInventor: Kiichi Ueyanagi
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Patent number: 6275463Abstract: An optical head comprises a photodetector 8 having divided photosensitive areas to detect light 13 reflected from an optical disk 7, means 10, 11, 12 for obtaining track error signal by operating signals from the photosensitive areas. The photodetector 8 has a first division line 9a parallel to an information track on the optical disk and second and third division lines 9b, 9c perpendicular to the first division line 9f and symmetrical to the optical axis. Further, a light-shielding area 8i is provided for shielding a part of the reflected light between the division lines 9b and 9c. The signals are operated to reduce offset of the tracking error signal due to a shift of object lens and a tilt of the optical disk. Accordingly, the optical head of the present invention has a small offset of tracking error signal with a simple structure.Type: GrantFiled: April 23, 1998Date of Patent: August 14, 2001Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Takayuki Nagata, Akihiro Arai, Toru Nakamura, Takao Hayashi
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Patent number: 6272099Abstract: The objective lens of the present invention includes a center portion and a periphery portion surrounding the center portion. An aberration of the periphery portion is corrected such that a light spot is formed by the convergence of a luminous flux which has been transmitted through the periphery portion and then transmitted through a first light transmissive flat plate, and an aberration of the center portion is corrected such that a light spot is formed by the convergence of a luminous flux which has been transmitted through the center portion and then transmitted through a second light transmissive flat plate which is thicker than the first light transmissive flat plate.Type: GrantFiled: April 14, 2000Date of Patent: August 7, 2001Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Sadao Mizuno, Yoshiaki Komma
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Patent number: 6269057Abstract: An improved focus error signal generator device including two optical lenses in series; a birefringent optical lens followed by a standard optical lens, the lenses being disposed in the path of a return read beam wherein the birefringent optical lens has a first and second focal plane. A pinhole is disposed in the path of the return read beam in close proximity to the first and second focal planes. A polarizing beam splitter is positioned after the second focal plane and serves to split the return read beam into two light beams of polarization associated with the first and second focal planes. First and second detectors are positioned so as to read the two light beams signals output from the polarizing beam splitter and the detectors are connected to an electrical differencing circuit having an output to an optical head servo system.Type: GrantFiled: January 12, 1999Date of Patent: July 31, 2001Assignee: Siros Technologies, Inc.Inventors: Mark E. McDonald, Robert R. McLeod
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Publication number: 20010009541Abstract: A laser beam emitted from a semiconductor laser enters an incident surface of a transparent condensing medium with a central part of the laser beam being shielded by a shading metal member, and a light spot is formed on a light-condensed surface of the transparent condensing medium. When this light spot is applied to a micro metal member, plasmon of the micro metal member is excited, and near field light leaks out therefrom. The near field light enters a recording medium of a disk as propagation light, and record into and and reproduction from the recording medium is performed by this light. By shielding the central part of the laser beam, it is possible to prevent the propagation light from being generated from the light-condensed surface of the transparent condensing medium, and to prevent erroneous reproduction caused by the propagation light.Type: ApplicationFiled: December 26, 2000Publication date: July 26, 2001Applicant: Fuiji Xerox Co., Ltd.Inventor: Kiichi Ueyanagi
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Patent number: 6266315Abstract: An optical focusing system which uses a light beam emitted from a light source, includes a refractive surface on one side of the optical focusing system and having a first radius of curvature, a first reflection surface on the above one side, surrounding the refractive surface and having a second radius of curvature being different from the first radius of curvature, a transparent beam focusing surface on the other side of the optical focusing system, and a second reflection surface on the above other side and surrounding the beam focusing surface. The refractive surface refracts an incident light beam, the second reflection surface reflects a light beam refracted by the refractive surface toward the first reflection surface, and the first reflection surface focuses a laser light beam reflected from the second reflection surface on the beam focusing surface as a focused beam spot. The optical focusing system can be used in an optical pickup.Type: GrantFiled: November 20, 1998Date of Patent: July 24, 2001Assignee: Samsung Electronics Co., Ltd.Inventors: Chul-Woo Lee, Chong-Sam Chung, Yong-Moon Lee, Cheol-Sung Yeon, Joong-Eon Seo, Young-Min Cheong, Dong-Ho Shin, Kun-Mo Cho, Pyong-Yong Seong, Jang-Hoon Yoo
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Patent number: 6256281Abstract: A volume holographic memory-based optical information-recording/reproducing apparatus being capable of controlling an interference area formed by a reference beam and a signal beam within a recording medium more easily than by waveform shaping using a lens. A recording medium is installed in the apparatus for recording a three-dimensional optical interference pattern formed by at least two coherent light beams as spatial changes in refractive index of the recording medium. A signal beam optical system transmits a coherent signal beam to the recording medium through a Fourier transform lens. A reference beam optical system transmits a coherent reference beam to the recording medium. The reference beam intersects the signal beam within the recording medium, and an angle of intersection between the reference beam and the signal beam is changed. Diffracted light of the reference beam diffracted from the recording medium is detected.Type: GrantFiled: March 24, 1999Date of Patent: July 3, 2001Assignee: Pioneer CorporationInventors: Satoru Tanaka, Takashi Yamaji, Hideki Hatano
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Publication number: 20010004348Abstract: The present invention relates to an optical head, a magneto-optical head, and a disk apparatus, that have high light efficiency, can realize high-density recording medium and perform high-speed recording and reproduction, and can prevent erroneous record or erroneous reproduction, and a manufacturing method of the optical head. When a converged beam enters an incident surface of a transparent condensing medium, its refracted beam is condensed on a light-condensed surface and forms a light spot. Since leaking out to an aperture formed on an outer surface of the light-condensed surface of this light spot, near field light is scattered by a micro metal member. In addition, since, also in the micro metal member, plasmon resonance occurs by the irradiation of a laser beam, near field light leaks out therefrom. This near field light becomes propagation light and enters a recording medium of a disk, and recording into the recording medium is performed by this light.Type: ApplicationFiled: December 14, 2000Publication date: June 21, 2001Applicant: Fuji Xerox co., LTD.Inventor: Kiichi Ueyanagi
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Patent number: 6222801Abstract: An optical pickup includes a variable iris having a numerical aperture is adjusted according to wavelength of light and can be compatibly used for discs having respectively different specifications.Type: GrantFiled: March 12, 1999Date of Patent: April 24, 2001Assignee: Samsung Electronics Co., Ltd.Inventors: Jang-Hoon Yoo, Pyong-Yong Seong, Yong-Jae Lee, Tae-Kyung Kim, Yong-Ki Son
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Patent number: 6212154Abstract: An optical pickup using a light-emitting diode (LED), which is capable of forming a light spot of an appropriate size for high-density recording/reproduction. The optical pickup includes a light-emitting diode (LED) to generate and emit light; a condensing unit to condense the light emitted from the LED; an optical filter to selectively transmit a predetermined wavelength of the light emitted from the LED; a spatial filter having a pin-hole, to limit a transmission range of the light condensed by the condensing unit; and a collimating lens to condense the divergent light passed through the spatial filter to form a parallel light. The parallel light is directed by a beam splitter toward an objective lens which focuses the parallel light on an optical disk. The light reflected from the optical disk is received by a photodetector.Type: GrantFiled: June 10, 1998Date of Patent: April 3, 2001Assignee: Samsung Electronics Co., Ltd.Inventors: Jang-hoon Yoo, Chul-woo Lee
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Patent number: 6178151Abstract: An optical head includes: a light source; a photodetector for generating a prescribed signal based on light which the photodetector receives; a converging optical system for converging a light beam emitted from the light source to be incident upon a prescribed reflective member; and a reproducing optical system for guiding reflected light from the prescribed reflective member to the photodetector. The reproducing optical system is configured for converging light on a prescribed converging point, and a filter having a light transmissive region for allowing light in the vicinity of a center of the converged light to selectively pass therethrough is provided in the vicinity of the converging point. The light transmissive region of the filter is formed by light which has passed through at least a part of the reproducing optical system and has been converged.Type: GrantFiled: April 9, 1998Date of Patent: January 23, 2001Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Yasumori Hino, Norio Miyatake, Masahiro Birukawa, Tadashi Nakamura
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Patent number: 6167019Abstract: An optical disc reproducing apparatus includes a semiconductor laser, an objective lens converging a laser beam from the semiconductor laser on a recording surface of an optical disc, a polarization plane rotating unit selectively rotating the plane of polarization of the laser beam according to the thickness of a substrate of the optical disc, and a polarizing filter selectively shading a peripheral portion of the laser beam having the rotated plane of polarization. In one embodiment, a numerical aperture changing unit includes a non-patterned twisted nematic liquid crystal, and the polarizing filter includes a polarizing film having a polarization characteristics at its peripheral portion.Type: GrantFiled: December 29, 1999Date of Patent: December 26, 2000Assignee: Sanyo Electric Co., Ltd.Inventors: Yoichi Tsuchiya, Seiji Kajiyama, Yasuyuki Kanou, Shuichi Ichiura
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Patent number: 6147955Abstract: An optical pickup device which is efficient in light use having little spherical aberration. The optical pickup device of an optical pickup includes an objective lens, disposed opposite a disk, having a light passing region divided into central, intermediate and periphery regions corresponding to a near axis area, an intermediate axis area and a far axis area of incident light, where the curvature of the central and peripheral regions is optimized for a thin disk and that of the intermediate region is optimized for a thick disk; a light source irradiating light toward a disk through the objective lens; a photo detector for detecting light reflected from the disk; and a beam splitter, disposed between the objective lens and the light source, for transmitting light from the light source toward the objective lens and for diffracting light reflected from the disks toward the photo detector.Type: GrantFiled: April 14, 1999Date of Patent: November 14, 2000Assignee: Samsung Electronics Co., Ltd.Inventors: Chul-woo Lee, Jang-hoon Yoo
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Patent number: 6137764Abstract: An optical disc reproducing apparatus includes a semiconductor laser, an objective lens converging a laser beam from the semiconductor laser on a recording surface of an optical disc, a polarization plane rotating unit selectively rotating the plane of polarization of the laser beam according to the thickness of a substrate of the optical disc, and a polarizing filter selectively shading a peripheral portion of the laser beam having the rotated plane of polarization. In one embodiment, a numerical aperture changing unit includes a non-patterned twisted nematic liquid crystal, and the polarizing filter includes a polarizing film having a polarization characteristics at its peripheral portion.Type: GrantFiled: December 29, 1999Date of Patent: October 24, 2000Assignee: Sanyo Electric Co., Ltd.Inventors: Yoichi Tsuchiya, Seiji Kajiyama, Yasuyuki Kanou, Shuichi Ichiura
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Patent number: 6122242Abstract: An optical disc reproducing apparatus includes a semiconductor laser, an objective lens converging a laser beam from the semiconductor laser on a recording surface of an optical disc, a polarization plane rotating unit selectively rotating the plane of polarization of the laser beam according to the thickness of a substrate of the optical disc, and a polarizing filter selectively shading a peripheral portion of the laser beam having the rotated plane of polarization. In one embodiment, a numerical aperture changing unit includes a non-patterned twisted nematic liquid crystal, and the polarizing filter includes a polarizing film having a polarization characteristics at its peripheral portion.Type: GrantFiled: December 29, 1999Date of Patent: September 19, 2000Assignee: Sanyo Electric Co., Ltd.Inventors: Yoichi Tsuchiya, Seiji Kajiyama, Yasuyuki Kanou, Shuichi Ichiura
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Patent number: 6111828Abstract: A focus error signal generator device including first and second optical lenses disposed in the respective paths of first and second light beams derived from the return read beam wherein the first and second optical lens have corresponding points of focus, and first and second detectors disposed in the corresponding paths of the first and second light beams located after the points of focus. First and second pinholes are disposed in the corresponding paths of the first and second light beams after the corresponding optical lens and before the corresponding detector, and an electrical differencing circuit having inputs to the first and second detectors and an output to an optical head servo system.Type: GrantFiled: January 12, 1999Date of Patent: August 29, 2000Assignee: Siros Technologies, Inc.Inventors: Robert R. McLeod, Mark E. McDonald
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Patent number: 6111842Abstract: An optical head has a light source for emitting a light beam; optical device for condensing the emitted light beam onto an information recording medium and condensing light reflected from the information recording medium; and aperture limitation device for, of the condensed reflected light, causing light of a predetermined outer region to exit in a position different from a position where light of an inner region exits, wherein the light of the outer region and the light of the inner region caused to exit by the aperture limitation devices are separated to different places.Type: GrantFiled: January 29, 1998Date of Patent: August 29, 2000Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Seiji Nishino, Hiroaki Yamamoto, Ken'ichi Kasazumi, Shin-ichi Kadowaki
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Patent number: 6104691Abstract: The present invention provides an objective lens unit which can be simultaneously adjusted to an NA specification and a substrate thickness of an optical recording medium.The objective lens unit for applying a beam to an optical recording medium so as to read and/or record from/to the optical recording medium includes: a first lens; a second lens; a cylindrical frame for movably supporting the second lens with respect to the first lens in a direction of an optical axis; and diaphragm means provided in the vicinity of the second lens and movable together with the second lens in the direction of the optical axis, for shading a part of the beam to be applied to the optical recording medium.The present invention also provides a recording/reproduction apparatus having the aforementioned objective lens unit, enabling to preferably write and read a data signal into/from an optical recording medium of different specifications.Type: GrantFiled: November 4, 1997Date of Patent: August 15, 2000Assignee: Sony CorporationInventors: Kenji Yamamoto, Isao Ichimura, Fumisada Maeda, Toshio Watanabe, Kiyoshi Ohsato
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Patent number: 6088322Abstract: An optical disk reader or read/write system for CD or DVD formats. First and second laser diodes operating at different wavelengths have their output beams collimated and directed at a single element objective lens, and are then reflected off the disk back through the lens to a photodetector. The single element objective lens has a central aperture zone and an outer aperture zone, the central zone being profiled to operate at a first numerical aperture at approximately 0.45 and the output beam of the first laser diode is confined to the central aperture zone. The outer aperture zone together with the central aperture zone are profiled to operate at a second numerical aperture, for example 0.60 wherein the output beam of the second laser diode has ray fans extending across the full aperture of the single element objective lens.Type: GrantFiled: May 7, 1998Date of Patent: July 11, 2000Inventors: Barry G. Broome, Jenkin A Richard
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Patent number: 6072762Abstract: Between a semiconductor laser diode and an optical disk, a collimator lens for collimating a laser beam output from the semiconductor laser diode, a liquid crystal optical shutter for attenuating the collimated beam having passed through the collimator lens, and a beam splitter for splitting reflected light from the optical disk are disposed. In addition, a collective lens for collecting the collimated beam obtained by the collimator lens on a data holding surface of the optical disk is further disposed.Type: GrantFiled: April 13, 1999Date of Patent: June 6, 2000Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masahiro Kume, Yuzaburo Ban, Isao Kidoguchi, Satoshi Kamiyama, Ayumu Tsujimura, Akihiko Ishibashi, Yoshiaki Hasegawa, Ryoko Miyanaga
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Patent number: 6072763Abstract: Disclosed is an optical head device for projecting a laser spot on an optical disk and reading out recorded information by detecting a recording state recorded on a recording surface of the optical disk, which has: a collimator lens which converges divergent light emitted from a semiconductor laser; and a pinhole member which removes a wavefront aberration at an outline portion of the light converged by the collimator lens; wherein the collimator lens and the pinhole member are disposed in an image-forming optical system, where a microspot is produced, from the semiconductor laser as a light source to an objective lens, and a wavefront aberration of the semiconductor laser is removed to minimize a wavefront aberration of the image-forming optical system.Type: GrantFiled: October 27, 1997Date of Patent: June 6, 2000Assignee: NEC CorporationInventor: Junichi Takahashi
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Patent number: 6069860Abstract: The objective lens of the present invention includes a center portion and a periphery portion surrounding the center portion. An aberration of the periphery portion is corrected such that a light spot is formed by the convergence of a luminous flux which has been transmitted through the periphery portion and then transmitted through a first light transmissive flat plate, and an aberration of the center portion is corrected such that a light spot is formed by the convergence of a luminous flux which has been transmitted through the center portion and then transmitted through a second light transmissive flat plate which is thicker than the first light transmissive flat plate.Type: GrantFiled: November 18, 1997Date of Patent: May 30, 2000Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Sadao Mizuno, Yoshiaki Komma
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Patent number: 6055220Abstract: An optical disk drive uses an air-bearing slider that supports a solid immersion lens (SIL) with a patterned thin film formed at the focus of the SIL to act as a secondary radiation source. The thin film is patterned to define either an "aperture" or a "scatterer", both of which localize the interaction of the disk drive's incident light beam with the underlying optical disk to create an effectively smaller light spot. In one embodiment the patterned thin film is opaque with a small aperture having a diameter less than the wavelength of the incident light beam. The aperture localizes the transmission of the incident light beam to the area of the aperture and generates an evanescent field that interacts with the optical disk. In a second embodiment, the patterned thin film is metallic and formed as dot that serves as a scatterer. The scatterer acts as an antenna or secondary light source to locally reradiate a portion of the incident light beam to the optical disk.Type: GrantFiled: March 31, 1998Date of Patent: April 25, 2000Assignee: International Business Machines CorporationInventors: Harry Jonathon Mamin, Daniel Rugar, Bruce David Terris
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Patent number: 6052353Abstract: An optical element has a diffraction grating pattern formed on a double refracting thin plate around a centrally-disposed region of a desired shape. The diffraction grating pattern is composed of equally spaced ion exchange regions each having a predetermined width, a predetermined length and a predetermined thickness in the direction of optical axis of incident light thereon and dielectric films each formed all over the top surface of one of the ion exchange region. The thicknesses of each ion exchange region and each dielectric film are selected such that the diffraction grating pattern allows the passage therethrough of an ordinary ray and inhibit the passage therethrough of a zero-order diffracted wave of an extraordinary ray. The optical element permits implementation of an easy-to-handle optical pickup that facilitates miniaturization of the playback system.Type: GrantFiled: October 16, 1997Date of Patent: April 18, 2000Assignee: Toyo Communication Equipment Co., Ltd.Inventor: Mitsuru Fujita
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Patent number: 6052343Abstract: To provide an optical head having a shading slit wherein aberration characteristic is effectively improved without hindering the high-speed operation or the miniaturization thereof, an optical head has an optical system for detecting a light reflected from a micro spot of an optical disk where a laser light is converged by an object lens (4), which comprises a shading slit (3) for restricting the laser light to pass through opposite peripheries of the object lens.Type: GrantFiled: September 8, 1997Date of Patent: April 18, 2000Assignee: NEC CorporationInventor: Yutaka Yamanaka
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Patent number: 6049518Abstract: An optical disc reproducing apparatus includes a semiconductor laser, an objective lens converging a laser beam from the semiconductor laser on a recording surface of an optical disc, a polarization plane rotating unit selectively rotating the plane of polarization of the laser beam according to the thickness of a substrate of the optical disc, and a polarizing filter selectively shading a peripheral portion of the laser beam having the rotated plane of polarization. In one embodiment, a numerical aperture changing unit includes a non-patterned twisted nematic liquid crystal, and the polarizing filter includes a polarizing film having a polarization characteristics at its peripheral portion.Type: GrantFiled: June 21, 1996Date of Patent: April 11, 2000Assignee: Sanyo Electric Co., Ltd.Inventors: Yoichi Tsuchiya, Seiji Kajiyama, Yasuyuki Kanou, Shuichi Ichiura
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Patent number: 6023450Abstract: An optical pickup capable of multiple track scanning, including a light source having at least two vertical cavity surface emitting lasers (VCSELs) to emit at least two or more light beams and a light controlling device for controlling the focal position of a light formed on one type of recording medium of two formats of different thicknesses, is provided. The light emitted from each VCSEL is focused on adjacent tracks of the recording medium via a polarization beam splitter, the light controlling device and an objective lens in sequence, and the light reflected from the recording medium is received by a photodetector via the objective lens, the light controlling device and the polarization beam splitter. The number of photodetectors correspond to the number of VCSELs to receive lights corresponding to each track.Type: GrantFiled: October 29, 1997Date of Patent: February 8, 2000Assignee: Samsung Electronics Co., Ltd.Inventors: Soo-han Park, Jong-hwa Won, Chun-seong Park
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Patent number: 6014360Abstract: By using a semiconductor laser of a relatively long wavelength relative to the track pitch of an optical recording medium, and the optical super-resolution technique, there are provided an optical head and an optical recording apparatus which permit processing such as recording and regeneration onto and from a conventional CD-R with no problems, and processing of an optical recording medium of the DVD standard with a high recording density. In the optical head and the optical recording apparatus of the present invention, a semiconductor laser having a relatively long wavelength relative to the track pitch of an optical recording medium can be used. The invention therefore provides an optical head and an optical recording apparatus which overcome the limit on efforts toward a higher density, and permit recording and regeneration at a high recording density at a low cost with a high reliability.Type: GrantFiled: November 14, 1997Date of Patent: January 11, 2000Assignee: Seiko Epson CorporationInventors: Masatoshi Yonekubo, Toshio Arimura, Takao Miyazawa
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Patent number: 6009066Abstract: An optical pickup compatible with at least two types of optical recording media using light beams having respectively different wavelengths for recording and reproducing information. In the optical pickup, a first laser light source emits a light beam having a relatively shorter wavelength. A first photodetector detects a reflected light beam with respect to the relatively shorter wavelength. An objective lens forms an annular shielding region between a near axis region of a relatively smaller radius and a far axis region of a relatively larger radius. A laser unit emits a light beam having a relatively longer wavelength, and detects only a light beam passing though the near axis region in the objective lens among reflected light beams having the relatively longer wavelength.Type: GrantFiled: November 19, 1998Date of Patent: December 28, 1999Assignee: Samsung Electronics Co., Ltd.Inventors: Jang-Hoon Yoo, Chul-Woo Lee
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Patent number: 5995473Abstract: An optical pickup system for selectively detects an information signal from, e.g., a pair of optical disks loaded on a disk tray, wherein each of the optical disks may have a different thickness. The optical pickup system includes a light source for generating a first and a second light beams having a different wavelength from each other, a first wavelength .lambda..sub.1, and a second wavelength .lambda..sub.2, and a beam splitter provided with a first and a second parts, wherein the first light beam impinging onto the first part is partially reflected to the first optical disk, and the second light beam impinging onto the second part is partially reflected to the second optical disk, thereby allowing the optical pickup system to detect an information signal from the respective optical disks.Type: GrantFiled: July 22, 1997Date of Patent: November 30, 1999Assignee: Daewoo Electronics Co., Ltd.Inventor: Yang-Oh Choi
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Patent number: 5991255Abstract: It is an object of the invention to provide a compatible optical head apparatus for optical disks with different thicknesses. A laser beam emitted by a semiconductor laser is convert into a collimated laser beam by a collimator lens and passes through a circular aperture, hence an effective NA of an objective lens is reduced. Accordingly, the effective NA for the incident laser beam on the optical disks is lower than that for the reflected laser beam from the optical disk by more than 0.1. Moreover, in the optical head apparatus according to another embodiment, another semiconductor laser with a different lasing wavelength is provided, and when a recorded signal of the optical disk with a wavelength dependent characteristic is reproduced, only one of the semiconductor lasers is activated in accordance with the characteristic of the optical disk to be reproduced.Type: GrantFiled: October 27, 1997Date of Patent: November 23, 1999Assignee: NEC CorporationInventor: Junichi Takahashi
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Patent number: 5986993Abstract: An optical pickup device which can obtain a stable reproduction signal by increasing the numerical aperture of an objective lens includes an objective lens facing a disc, a light source for radiating light to the disc via the objective lens, a beam splitter provided between the light source and objective lens for directing the light reflected from the disc in a path different from that of the light travelled from the light source, a photodetector for detecting the light reflected from the disc and travelled via the beam splitter, and a diaphragm provided between the beam splitter and light source and having a predetermined numerical aperture.Type: GrantFiled: January 7, 1997Date of Patent: November 16, 1999Assignee: Samsung Electronics Co., Ltd.Inventors: Jang-hoon Yoo, Chul-woo Lee, Kyung-hwa Rim
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Patent number: 5946282Abstract: An optical recording/reproduction apparatus records and reproduces information onto and from an associated recording medium by use of light from a light source. The apparatus includes a lens capable of generating an evanescent wave which is disposed in a light path from the light source to the recording medium, and a partial beam light intercepter for intercepting at least part of the light passing through the lens without contributing to generation of the evanescent wave. The light intercepter blocks the center part of a laser beam incident to the evanescent wave generating lens, thus reshaping it into a beam of hollow annular cross-section. This improves the optical resolution of the record/reproduction apparatus.Type: GrantFiled: July 24, 1998Date of Patent: August 31, 1999Assignee: Kabushiki Kaisha ToshibaInventors: Masatoshi Hirono, Yoriyuki Ishibashi
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Patent number: 5940359Abstract: Apparatus for interposing additional optical elements in the optical path of an optical read/write device includes said additional element mounted on a carrier pivotally mounted on a lens carrier which is subject to lateral translation. Stops on the carrier to which the additional element is mounted engage actuators arranged at the limits of lateral travel of the lens carrier, which limits are beyond the recordable areas of the recording medium. The engagement of the actuators with the carrier causes the carrier to pivot and either insert or remove the additional optical element in the optical path of the apparatus. Magnetic retainers are included to prevent the additional element from moving from the desired position.Type: GrantFiled: March 24, 1997Date of Patent: August 17, 1999Assignee: Deutsche Thomson-Brandt GmbHInventors: Heinz-Joerg Schroeder, Dietmar Uhde, Fritz Weisser
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Patent number: 5930224Abstract: An aberration correcting mechanism includes a corrective optical glass for correcting a spherical aberration and a link mechanism for movably supporting the corrective optical glass. The corrective optical glass is a parallel, flat plate having the same refractive index as that of a cover glass of a disk, and its length is slightly greater than the moving distance of an objective. The link mechanism has first and second links. While one end of each of the links is rotatably attached to its corresponding end portion of the corrective optical glass, the other ends of the links are rotatably mounted on the mounting portions on a deck base. The link mechanism also has a third link and a solenoid, and one end of the third link is rotatably attached to the central portion of the second link, while the other end of the third link is rotatably attached to the solenoid. The solenoid is fixed to a fixed portion on the deck base.Type: GrantFiled: July 15, 1997Date of Patent: July 27, 1999Assignee: Olympus Optical Co., Ltd.Inventor: Tetsuo Ikegame
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Patent number: 5926450Abstract: An optical scanning device can scan two types of record carriers each having a transparent layer with a different thickness, in which a focused radiation beam scans an information layer of the record carrier through the transparent layer. When scanning a first type of record carrier the best focus of the radiation beam is positioned on the information layer and when scanning a second type of record carrier the paraxial focus of the radiation beam is positioned on the information layer. The lens system focusing the radiation beam comprises an opaque ring between a transparent central area and a transparent annular area.Type: GrantFiled: March 6, 1997Date of Patent: July 20, 1999Assignee: U.S. Philips CorporationInventor: Josephus J. M. Braat
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Patent number: 5910937Abstract: An optical pickup apparatus for an information reproducing apparatus is adapted to reproduce one of at least first and second type optical record media which is loaded on the information reproducing apparatus. The first and second type optical record media have distances from surfaces to information record planes different from each other.Type: GrantFiled: March 26, 1998Date of Patent: June 8, 1999Assignee: Pioneer Electronic CorporationInventors: Taichi Akiba, Akira Miura
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Patent number: 5901131Abstract: An optical pickup of a compatible type which can be switched for a DVD and a CD by a completely electrical control without the need of a mechanical moving device or the like and is suitable for the reduction in size and also has an excellent efficiency in the use of light. A liquid crystal panel of a transmission type which gives a phase difference of a 1/4 wavelength or a wavelength that is an odd number multiple of 1/4 wavelength to a transmission light and has a transparent electrode having an aperture pattern of a predetermined shape is used and the liquid crystal panel is arranged so that its plane of polarization crosses a plane of polarization of a polarization beam splitter at a predetermined angle.Type: GrantFiled: December 18, 1997Date of Patent: May 4, 1999Assignee: Pioneer Electronic CorporationInventors: Sakashi Ootaki, Masayuki Iwasaki
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Patent number: 5894466Abstract: An optical pickup device includes a light source which emits a laser beam to an optical disk. An objective lens converts the emission beam into a converging beam, the converging beam passing through a transparent layer of the optical disk and forming a light spot on a recording surface of the optical disk. A photodetecting unit generates a read-data signal based on a reflection beam from the optical disk. A beam converting unit converts a reflection beam directed to the photodetecting unit such that the reflection beam is allowed to enter the photodetecting unit when a first optical disk is accessed, and a central portion of the reflection beam is allowed to enter the photodetecting unit and a peripheral portion of the reflection beam is inhibited from entering the photodetecting unit when a second optical disk is accessed.Type: GrantFiled: October 7, 1997Date of Patent: April 13, 1999Assignee: Ricoh Company, Ltd.Inventor: Hiroshi Akiyama
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Patent number: 5889748Abstract: The objective lens has a numerical aperture NA=0.6 when reproducing a DVD having a thickness of 0.6 mm and NA=0.42 when reproducing a CD having a thickness of 1.2 mm. At a boundary of NA 0.42, a slight stepped portion is formed so as to establish a phase difference. In this case, a designed wavelength is 0.635 .mu.m, and an optimum designed substrate thickness of a central portion is approximately 0.8 mm. While the DVD is reproduced, wave front aberration is on the order of 0.025.lambda., and jitter contained in the reproduction signal of the CD is equivalent to the present jitter. As a consequence, such an objective lens and an optical head with employment of this objective lens are provided, which precisely reproduce signals from the CD having the substrate thickness of 1.2 mm, and the DVD having the substrate thickness of 0.6 mm.Type: GrantFiled: December 26, 1996Date of Patent: March 30, 1999Assignees: Hitachi, Ltd., Hoya CorporationInventors: Takeshi Shimano, Masayuki Inoue, Akira Arimoto, Hiroyuki Minemura, Hisao Fujita, Hideaki Koyanagi
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Patent number: 5875167Abstract: Disclosed is an optical head device, including: a first light source which emits light with a first wavelength; a second light source which emits light with a second wavelength; first and second optical detectors; an optical coupling and dividing means in which light emitted from the first light source and light emitted from the second light source are coupled and are each respectively led to an optical recording medium having a first and a second substrate thickness, and in which the lights emitted from the first and second light sources, and reflected on the optical recording medium, are led to the first and second optical detectors, respectively; and, a lens system which is disposed between the optical coupling and dividing means and the optical recording medium, and includes an objective lens; wherein the second substrate thickness is set to be greater than the first substrate thickness, and an effective optical path length from the second light source to the lens system is set to be shorter than an effecType: GrantFiled: February 6, 1997Date of Patent: February 23, 1999Assignee: NEC CorporationInventor: Ryuichi Katayama
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Patent number: 5872761Abstract: The present invention comprises an arrangement with removable optical element having a predetermined focal distance in the light path between a light source and an objective lens, so as to insert said optical element into the light path between the light source and the objective lens for playing back or recording onto one type of thickness of disk plates, as well as to remove it therefrom for playing back or recording onto another type of thickness of disk plates. Alternatively, by retaining variably the distance between the light source and the collimator lens, the distance between the light source and the collimator lens along with the light path is variably changed according to the thickness of the disk plate being inserted. Then by determining the type of the disk inserted and accordingly selectably inserting/removing the optical element, only one objective lens may be used to conform to the disk plates having different thicknesses.Type: GrantFiled: August 28, 1997Date of Patent: February 16, 1999Assignee: Hitachi, Ltd.Inventors: Yasuyuki Sugi, Toshio Sugiyama, Nobuo Imada, Hidenori Shinohara, Yukio Fukui
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Patent number: 5870369Abstract: An objective lens device having two light control surfaces and an optical pickup able to adopt disks having different thicknesses as a recording medium. The objective lens device includes an objective lens arranged along an optical path parallel to the disks, and first and second control portions formed in a light incident surface of the objective lens, a light emitting surface thereof, or an extra transparent member. Therefore, two disks having different thicknesses are compatible as a recording medium, and light interference occurring when using a thick disk can be decreased.Type: GrantFiled: February 13, 1997Date of Patent: February 9, 1999Assignee: Samsung Electronics Co., Ltd.Inventors: Chong-sam Chung, Chul-woo Lee, Pyong-yong Seong
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Patent number: 5867468Abstract: An optical pickup includes a light source, a light converging portion for converging a light emitted from the light source on the recording surface of an optical disk, a signal detecting portion for detecting a light reflected by the recording surface and converting this light into a specified electric signal, a first optical element, which is arranged between the light source and the light converging portion for forming a plurality of diffracted lights from the light emitted from the light source, and a second optical element, which is arranged between the light source and the light converging portion and in which an optical path for the light reflected by the recording surface of the optical disk and an optical path for the emitted light are different from each other.Type: GrantFiled: March 10, 1997Date of Patent: February 2, 1999Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Taiichi Mori, Masaharu Fukakusa
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Patent number: 5864523Abstract: A lens holder is provided with objective lenses of different types. Rotating the lens holder causes one of the objective lenses to be placed in the optical path of the laser beam. Near one objective lens, there is provided a reflecting element that reflects part of the laser beam directed to the objective lens. When the objective lens is put in the optical path, the beam from the reflecting element is sensed by a sensor. From the sensing result, it is judged that a specific type of objective lens is in the optical path. Accordingly, there is provided an objective lens driving apparatus that includes at least two objective lenses with different numerical apertures according to optical information recording mediums complying with different standards, is capable of switching between the objective lenses according to the optical information recording medium to be used, and further has a simple structure capable of identifying the type of the objective lens selected by switching.Type: GrantFiled: November 8, 1996Date of Patent: January 26, 1999Assignee: Kabushiki Kaisha ToshibaInventor: Takashi Yoshizawa
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Patent number: 5850380Abstract: A photomagnetic head apparatus includes a beam splitter which splits a laser beam, reflected by concentric recording tracks of a rotating photomagnetic recording disc, into three bundles of rays. The three bundles of rays have different polarization directions in a plane which lies in a radial direction of the recording tracks. One of the three bundles of rays is used as a servo-signal light, and the remaining two bundles of rays are used as data signal lights. A defocusing diffraction element splits at least the servo-signal light into a least two bundles of rays in a direction corresponding to the tangential direction of the recording tracks, substantially perpendicular to the split direction of the beam splitter and which provides at least two split lights with a predetermined amount of positive or negative defocus in an optical axis direction. A pair of servo-signal light receiving elements receive the split beams of the servo-signal light produced by the defocusing diffraction element.Type: GrantFiled: July 10, 1997Date of Patent: December 15, 1998Assignee: Asahi Kogaku Kogyo Kabushiki KaishaInventor: Wataru Kubo
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Patent number: 5844879Abstract: A masking member is provided so as to move in an interlocked manner with a shift of an objective lens designed for a high-density disk. Since the masking member reduces an effective numerical aperture (NA) of the objective lens, and greatly reduces affection of aberration, the objective lens allows a CD whose substrate is thicker than that of the high-density disk to be stably reproduced. Also, for example, even when the objective lens moves in a track direction of the high-density disk or CD, the masking member follows that movement. Therefore, a suitably sized light spot is formed on a signal surface of the high-density disk or CD. Especially, a light flux having passed inside the masking member with relatively small aberration is used to form a suitably sized light spot on the signal surface of the CD.Type: GrantFiled: March 31, 1997Date of Patent: December 1, 1998Assignee: Sharp Kabushiki KaishaInventors: Hideji Morita, Yasusi Seike
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Patent number: 5841755Abstract: In a magnetooptical information recording-reproducing apparatus, recording of information is performed such that a laser beam is irradiated on a magnetooptical information recording medium via an optical head while applying a magnetic field to the beam irradiated portion of the recording medium onto which information pits are formed by utilizing the difference in the direction of magnetization thereof. The magnetooptical information recording-reproducing apparatus is provided with a band-like shielding plate which is arranged in an optical path of a reflected light from the recording medium upon application of the laser beam thereto in a direction perpendicular to tracks of the recording medium. Reproduction of information recorded on the recording medium is effected by detecting the beam which is not shielded by the shielding plate by use of a photodetector.Type: GrantFiled: March 7, 1996Date of Patent: November 24, 1998Assignee: Canon Kabushiki KaishaInventors: Masakuni Yamamoto, Susumu Matsumura, Hiroaki Hoshi, Eiji Yamaguchi
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Patent number: RE36393Abstract: A system and a method for optical access of the surface of an optical disk (or another moving media information storage device) with a very short seek time is presented. The system uses two-dimensional deflection of a light (typically laser) beam. The beam reaches a stationary lenslet array, where, at a particular moment, it intercepts a single lenslet. The lenslet focuses the beam to a spot on the information storage surface of the disk. For reading information, the beam is reflected through the lenslet. Taking advantage of the "cat-eye" retro-reflection principle, only one detector (or very few detectors) is needed. Since only one spot at the surface is illuminated at any given moment, this spot gets most of the laser's light, allowing sufficient power concentration when needed for writing information on the disk.Type: GrantFiled: August 28, 1998Date of Patent: November 16, 1999Assignee: M.M.R.I. Photonics Ltd.Inventor: Isaia Glaser-Inbari