With Detail, Configuration, Or Adjunct Of Element Having Slit Or Aperture In Radiation Path Patents (Class 369/118)
  • Patent number: 6278679
    Abstract: 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: Grant
    Filed: August 5, 1997
    Date of Patent: August 21, 2001
    Assignee: Elop Eletro-Optics Industries Ltd.
    Inventors: Victor Weiss, Erez Hasman, Moshe Oron
  • Publication number: 20010014061
    Abstract: 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: Application
    Filed: January 30, 2001
    Publication date: August 16, 2001
    Applicant: FUJI XEROX CO., LTD
    Inventor: Kiichi Ueyanagi
  • Patent number: 6275463
    Abstract: 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: Grant
    Filed: April 23, 1998
    Date of Patent: August 14, 2001
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Takayuki Nagata, Akihiro Arai, Toru Nakamura, Takao Hayashi
  • Patent number: 6272099
    Abstract: 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: Grant
    Filed: April 14, 2000
    Date of Patent: August 7, 2001
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Sadao Mizuno, Yoshiaki Komma
  • Patent number: 6269057
    Abstract: 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: Grant
    Filed: January 12, 1999
    Date of Patent: July 31, 2001
    Assignee: Siros Technologies, Inc.
    Inventors: Mark E. McDonald, Robert R. McLeod
  • Publication number: 20010009541
    Abstract: 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: Application
    Filed: December 26, 2000
    Publication date: July 26, 2001
    Applicant: Fuiji Xerox Co., Ltd.
    Inventor: Kiichi Ueyanagi
  • Patent number: 6266315
    Abstract: 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: Grant
    Filed: November 20, 1998
    Date of Patent: July 24, 2001
    Assignee: 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
  • Patent number: 6256281
    Abstract: 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: Grant
    Filed: March 24, 1999
    Date of Patent: July 3, 2001
    Assignee: Pioneer Corporation
    Inventors: Satoru Tanaka, Takashi Yamaji, Hideki Hatano
  • Publication number: 20010004348
    Abstract: 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: Application
    Filed: December 14, 2000
    Publication date: June 21, 2001
    Applicant: Fuji Xerox co., LTD.
    Inventor: Kiichi Ueyanagi
  • Patent number: 6222801
    Abstract: 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: Grant
    Filed: March 12, 1999
    Date of Patent: April 24, 2001
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jang-Hoon Yoo, Pyong-Yong Seong, Yong-Jae Lee, Tae-Kyung Kim, Yong-Ki Son
  • Patent number: 6212154
    Abstract: 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: Grant
    Filed: June 10, 1998
    Date of Patent: April 3, 2001
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jang-hoon Yoo, Chul-woo Lee
  • Patent number: 6178151
    Abstract: 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: Grant
    Filed: April 9, 1998
    Date of Patent: January 23, 2001
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasumori Hino, Norio Miyatake, Masahiro Birukawa, Tadashi Nakamura
  • Patent number: 6167019
    Abstract: 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: Grant
    Filed: December 29, 1999
    Date of Patent: December 26, 2000
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Yoichi Tsuchiya, Seiji Kajiyama, Yasuyuki Kanou, Shuichi Ichiura
  • Patent number: 6147955
    Abstract: 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: Grant
    Filed: April 14, 1999
    Date of Patent: November 14, 2000
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Chul-woo Lee, Jang-hoon Yoo
  • Patent number: 6137764
    Abstract: 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: Grant
    Filed: December 29, 1999
    Date of Patent: October 24, 2000
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Yoichi Tsuchiya, Seiji Kajiyama, Yasuyuki Kanou, Shuichi Ichiura
  • Patent number: 6122242
    Abstract: 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: Grant
    Filed: December 29, 1999
    Date of Patent: September 19, 2000
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Yoichi Tsuchiya, Seiji Kajiyama, Yasuyuki Kanou, Shuichi Ichiura
  • Patent number: 6111828
    Abstract: 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: Grant
    Filed: January 12, 1999
    Date of Patent: August 29, 2000
    Assignee: Siros Technologies, Inc.
    Inventors: Robert R. McLeod, Mark E. McDonald
  • Patent number: 6111842
    Abstract: 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: Grant
    Filed: January 29, 1998
    Date of Patent: August 29, 2000
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Seiji Nishino, Hiroaki Yamamoto, Ken'ichi Kasazumi, Shin-ichi Kadowaki
  • Patent number: 6104691
    Abstract: 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: Grant
    Filed: November 4, 1997
    Date of Patent: August 15, 2000
    Assignee: Sony Corporation
    Inventors: Kenji Yamamoto, Isao Ichimura, Fumisada Maeda, Toshio Watanabe, Kiyoshi Ohsato
  • Patent number: 6088322
    Abstract: 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: Grant
    Filed: May 7, 1998
    Date of Patent: July 11, 2000
    Inventors: Barry G. Broome, Jenkin A Richard
  • Patent number: 6072762
    Abstract: 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: Grant
    Filed: April 13, 1999
    Date of Patent: June 6, 2000
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masahiro Kume, Yuzaburo Ban, Isao Kidoguchi, Satoshi Kamiyama, Ayumu Tsujimura, Akihiko Ishibashi, Yoshiaki Hasegawa, Ryoko Miyanaga
  • Patent number: 6072763
    Abstract: 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: Grant
    Filed: October 27, 1997
    Date of Patent: June 6, 2000
    Assignee: NEC Corporation
    Inventor: Junichi Takahashi
  • Patent number: 6069860
    Abstract: 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: Grant
    Filed: November 18, 1997
    Date of Patent: May 30, 2000
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Sadao Mizuno, Yoshiaki Komma
  • Patent number: 6055220
    Abstract: 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: Grant
    Filed: March 31, 1998
    Date of Patent: April 25, 2000
    Assignee: International Business Machines Corporation
    Inventors: Harry Jonathon Mamin, Daniel Rugar, Bruce David Terris
  • Patent number: 6052353
    Abstract: 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: Grant
    Filed: October 16, 1997
    Date of Patent: April 18, 2000
    Assignee: Toyo Communication Equipment Co., Ltd.
    Inventor: Mitsuru Fujita
  • Patent number: 6052343
    Abstract: 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: Grant
    Filed: September 8, 1997
    Date of Patent: April 18, 2000
    Assignee: NEC Corporation
    Inventor: Yutaka Yamanaka
  • Patent number: 6049518
    Abstract: 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: Grant
    Filed: June 21, 1996
    Date of Patent: April 11, 2000
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Yoichi Tsuchiya, Seiji Kajiyama, Yasuyuki Kanou, Shuichi Ichiura
  • Patent number: 6023450
    Abstract: 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: Grant
    Filed: October 29, 1997
    Date of Patent: February 8, 2000
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Soo-han Park, Jong-hwa Won, Chun-seong Park
  • Patent number: 6014360
    Abstract: 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: Grant
    Filed: November 14, 1997
    Date of Patent: January 11, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Masatoshi Yonekubo, Toshio Arimura, Takao Miyazawa
  • Patent number: 6009066
    Abstract: 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: Grant
    Filed: November 19, 1998
    Date of Patent: December 28, 1999
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jang-Hoon Yoo, Chul-Woo Lee
  • Patent number: 5995473
    Abstract: 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: Grant
    Filed: July 22, 1997
    Date of Patent: November 30, 1999
    Assignee: Daewoo Electronics Co., Ltd.
    Inventor: Yang-Oh Choi
  • Patent number: 5991255
    Abstract: 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: Grant
    Filed: October 27, 1997
    Date of Patent: November 23, 1999
    Assignee: NEC Corporation
    Inventor: Junichi Takahashi
  • Patent number: 5986993
    Abstract: 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: Grant
    Filed: January 7, 1997
    Date of Patent: November 16, 1999
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jang-hoon Yoo, Chul-woo Lee, Kyung-hwa Rim
  • Patent number: 5946282
    Abstract: 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: Grant
    Filed: July 24, 1998
    Date of Patent: August 31, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Hirono, Yoriyuki Ishibashi
  • Patent number: 5940359
    Abstract: 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: Grant
    Filed: March 24, 1997
    Date of Patent: August 17, 1999
    Assignee: Deutsche Thomson-Brandt GmbH
    Inventors: Heinz-Joerg Schroeder, Dietmar Uhde, Fritz Weisser
  • Patent number: 5930224
    Abstract: 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: Grant
    Filed: July 15, 1997
    Date of Patent: July 27, 1999
    Assignee: Olympus Optical Co., Ltd.
    Inventor: Tetsuo Ikegame
  • Patent number: 5926450
    Abstract: 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: Grant
    Filed: March 6, 1997
    Date of Patent: July 20, 1999
    Assignee: U.S. Philips Corporation
    Inventor: Josephus J. M. Braat
  • Patent number: 5910937
    Abstract: 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: Grant
    Filed: March 26, 1998
    Date of Patent: June 8, 1999
    Assignee: Pioneer Electronic Corporation
    Inventors: Taichi Akiba, Akira Miura
  • Patent number: 5901131
    Abstract: 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: Grant
    Filed: December 18, 1997
    Date of Patent: May 4, 1999
    Assignee: Pioneer Electronic Corporation
    Inventors: Sakashi Ootaki, Masayuki Iwasaki
  • Patent number: 5894466
    Abstract: 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: Grant
    Filed: October 7, 1997
    Date of Patent: April 13, 1999
    Assignee: Ricoh Company, Ltd.
    Inventor: Hiroshi Akiyama
  • Patent number: 5889748
    Abstract: 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: Grant
    Filed: December 26, 1996
    Date of Patent: March 30, 1999
    Assignees: Hitachi, Ltd., Hoya Corporation
    Inventors: Takeshi Shimano, Masayuki Inoue, Akira Arimoto, Hiroyuki Minemura, Hisao Fujita, Hideaki Koyanagi
  • Patent number: 5875167
    Abstract: 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 effec
    Type: Grant
    Filed: February 6, 1997
    Date of Patent: February 23, 1999
    Assignee: NEC Corporation
    Inventor: Ryuichi Katayama
  • Patent number: 5872761
    Abstract: 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: Grant
    Filed: August 28, 1997
    Date of Patent: February 16, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Yasuyuki Sugi, Toshio Sugiyama, Nobuo Imada, Hidenori Shinohara, Yukio Fukui
  • Patent number: 5870369
    Abstract: 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: Grant
    Filed: February 13, 1997
    Date of Patent: February 9, 1999
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Chong-sam Chung, Chul-woo Lee, Pyong-yong Seong
  • Patent number: 5867468
    Abstract: 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: Grant
    Filed: March 10, 1997
    Date of Patent: February 2, 1999
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Taiichi Mori, Masaharu Fukakusa
  • Patent number: 5864523
    Abstract: 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: Grant
    Filed: November 8, 1996
    Date of Patent: January 26, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Takashi Yoshizawa
  • Patent number: 5850380
    Abstract: 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: Grant
    Filed: July 10, 1997
    Date of Patent: December 15, 1998
    Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
    Inventor: Wataru Kubo
  • Patent number: 5844879
    Abstract: 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: Grant
    Filed: March 31, 1997
    Date of Patent: December 1, 1998
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hideji Morita, Yasusi Seike
  • Patent number: 5841755
    Abstract: 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: Grant
    Filed: March 7, 1996
    Date of Patent: November 24, 1998
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masakuni Yamamoto, Susumu Matsumura, Hiroaki Hoshi, Eiji Yamaguchi
  • Patent number: RE36393
    Abstract: 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: Grant
    Filed: August 28, 1998
    Date of Patent: November 16, 1999
    Assignee: M.M.R.I. Photonics Ltd.
    Inventor: Isaia Glaser-Inbari