Patents by Inventor Tsuneo Yanagida

Tsuneo Yanagida has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5555232
    Abstract: An optical head has a semiconductor laser for emitting light, a collimator lens for converting the light from the laser into a parallel light beam, a semiconductor substrate for reflecting the light beam, and an objective lens for focussing the light beam reflected from the substrate on the optical disk. A 1/4 wavelength plate is situated between the substrate and the objective lens. A beam splitter which transmits the light from the laser and reflects the light returning from the disk is provided between the collimator lens and the substrate. Following the beam splitter, a collective lens, a cylindrical lens and an optical detector are arranged in this order on an optical path for the returning light. A light receiving element for outputting a signal corresponding to the intensity of the light received is formed on the semiconductor substrate, and a polarizing film is formed on the surface thereof.
    Type: Grant
    Filed: November 9, 1994
    Date of Patent: September 10, 1996
    Assignee: Olympus Optical Co., Ltd.
    Inventors: Shohei Kobayashi, Takeshi Yamazaki, Tsuneo Yanagida, Haruhiko Takemura, Toshihiro Ogata
  • Patent number: 5249171
    Abstract: An opto-magnetic pick-up device for use in an information recording and reproducing device is disclosed. The device comprises a phase difference correcting device capable of correcting the phase difference between the linearly polarized component of the reflected light from the recording medium and a polarized component vertical to the linearly polarized component.
    Type: Grant
    Filed: May 1, 1991
    Date of Patent: September 28, 1993
    Assignee: Olympus Optical Company Ltd.
    Inventors: Nobuhide Matsubayashi, Tsuneo Yanagida, Kiichi Kato
  • Patent number: 5202877
    Abstract: An apparatus for detecting unused sectors in an optical disk or opto-magnetic disk including an envelope detection circuit for detecting an envelope of a read signal to derive an envelope detection signal when data is recorded in a data area of sector. Sector mark and address marks recorded in an identification area are detected to derive sector mark detection signal is generated and address mark detection signals, and an interpolated mark signal corresponding to a synchronizing signal recorded in the data area in accordance with the sector mark detection signal and address mark detection signals. When the envelope detection signal is not produced, the generation of the interpolated mark signal is inhibited. Thus when the synchronizing signal is not detected in the data area and the generation of the interpolated signal is inhibited, the relevant sector is detected as the unused sector.
    Type: Grant
    Filed: November 30, 1990
    Date of Patent: April 13, 1993
    Assignee: Olympus Optical Co., Ltd.
    Inventor: Tsuneo Yanagida
  • Patent number: 5159584
    Abstract: A photo-magnetic (magneto-optic) recording device having recording medium in the form of a rotating magnetic disc having magnetic characteristics in a direction perpendicular to its surface has a pickup head (7) disposed on one side of the disc and movable radially of the disc to scan selected areas of the disc. On the side of the disc opposite to that on which the pickup head is located, there are provided a plurality of coils (8) generating a bias-magnetic field applied to the disc. The coils are disposed in overlapping arrangement with their centers disposed on a line extending radially of the disc. The coils are energized by electric circuitry which comprises means for sensing the position of the pickup head and energizing a respective coil located in position to apply a bias-magnetic to the area of the disc scanned by the pickup head.
    Type: Grant
    Filed: September 19, 1991
    Date of Patent: October 27, 1992
    Assignee: Olympus Optical Company Limited
    Inventors: Tsuneo Yanagida, Kazuyasu Motoyama
  • Patent number: 5083303
    Abstract: Based on an output signal of a sector mark reading circuit reading a sector mark signal representing a sector mark area, the interval in which the next sector mark signal is to be detected is anticipated, and a quasi-sector mark is generated at a time when the next sector mark is to be detected in each sector. Even if the sector mark reading fails, the sector mark will be able to be output at an accurate timing. Also, if the read sector mark signal, which is mis-detected or not, is determined, a highly reliable sector mark signal may be produced.
    Type: Grant
    Filed: April 27, 1989
    Date of Patent: January 21, 1992
    Assignee: Olympus Optical Co., Ltd.
    Inventors: Tsuneo Yanagida, Motoo Azuma, Kenji Kikkawa
  • Patent number: 4837758
    Abstract: In the present invention, a discriminating means of recording media is formed in a cartridge containing a magneto-optical type recording media and in a cartridge containing other recording media, a sheltering height of a field applying means is changed according to the loading of each cartridge so that said field applying means is held close to the recording media in the case of the magneto-optical type cartridge while said means is sheltered high in the case of other type cartridge, and at the same time a discriminating means for recording media is provided to perform the signal processing corresponding to the recording media loaded.
    Type: Grant
    Filed: September 19, 1986
    Date of Patent: June 6, 1989
    Assignee: Olympus Optical Co., Ltd.
    Inventors: Kazuyasu Motoyama, Tsuneo Yanagida, Mitsugu Sakai, Hitoshi Ichikawa, Akihiko Yoshizawa
  • Patent number: 4757487
    Abstract: In a method of detecting track crossings on an optical disc, a light source irradiates a light beam onto an optical disc having guide tracks in the form of a recess and the light beam is reflected and diffracted into a zero order light beam and positive and negative primary light beams. The light beams are defocused so as to produce interference patterns between the zero light beam and the positive and negative primary light beams. The interference patterns are detected by a four split light detector disposed between two parts of a two split detector. The outputs of the detectors are fed to an adder and to a subtractor for producing a sum signal and a difference signal respectively. The sum signal and difference signal are fed to a phase detector. Defocusing of the light beams is effected by a focusing coil to which is fed the amplified output of an adder of a reference signal controlled by a control circuit.
    Type: Grant
    Filed: May 16, 1985
    Date of Patent: July 12, 1988
    Assignee: Olympus Optical Company Limited
    Inventors: Tsuneo Yanagida, Kiichi Kato
  • Patent number: 4472748
    Abstract: In a method of recording an information signal in an opto-magnetic record disc which has an easily magnetizable axis perpendicular to its surface, a constant erasing light beam and a modulated recording light beam are focussed by a single objective lens on adjacent tracks and an external magnetic field is applied to the record medium. The erasing and recording operations can be carried out at the same time by inverting the polarity of the external magnetic field track by track.
    Type: Grant
    Filed: December 31, 1981
    Date of Patent: September 18, 1984
    Assignee: Olympus Optical Co. Ltd.
    Inventors: Kiichi Kato, Tsuneo Yanagida
  • Patent number: D288558
    Type: Grant
    Filed: April 26, 1984
    Date of Patent: March 3, 1987
    Assignee: Olympus Optical Company, Ltd.
    Inventors: Haruhiko Takemura, Nobuhide Matsubayashi, Tsuneo Yanagida, Masaharu Sakamoto