Patents by Inventor Yoshifumi Masunaga

Yoshifumi Masunaga 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: 5850313
    Abstract: There is provided an objective lens driving device, wherein a lens holder for holding an objective lens and a coil unit is connected with and floatingly supported by a base block using a plurality of elongate flexible metal members. The objective lens driving device is formed by positioning a plurality of elongate flexible metal members at the predetermined positions with respect to the lens holder and the base block which are to be formed, forming the lens holder integrally connected with one end of each elongate flexible metal member, forming the base block integrally connected with the other end of each elongate flexible metal member, attaching the objective lens and the coil unit in the lens holder.
    Type: Grant
    Filed: January 3, 1997
    Date of Patent: December 15, 1998
    Assignee: Pioneer Electronic Corporation
    Inventors: Takahiro Miyagi, Shigeru Takaya, Yoshifumi Masunaga
  • Patent number: 5748579
    Abstract: An optical pickup magneto-optically records information on a magneto optical disc in cooperation with a magnetic head. The optical pickup is disposed at one surface side of the magneto optical disc while the magnetic head is disposed at the other surface side of the magneto optical disc during a recording operation of the magneto optical disc. The optical pickup is provided with: a light emission device for emitting a light beam; an optical system for guiding the emitted light beam; an objective lens for converging and focusing the guided light beam onto the optical disc; and an actuator holding the objective lens and having a magnetic circuit for actuating the objective lens to move in focusing and tracking directions respectively of the magneto optical disc by a magnetic force generated by the magnetic circuit.
    Type: Grant
    Filed: February 23, 1996
    Date of Patent: May 5, 1998
    Assignee: Pioneer Electronic Corporation
    Inventors: Takahiro Miyagi, Shigeru Takaya, Yoshifumi Masunaga
  • Patent number: 5734631
    Abstract: A disc player includes: a plurality of guide devices arranged radiately in radial directions of a disc from a rotary axis of the disc. Each of the guide devices includes two parallel shafts vertically arranged for supporting at least one pickup device in a manner slidable in the radial direction. The vertical positions of the parallel shafts of one of the guide devices are different from the vertical positions of the parallel shafts of the guide device neighboring to the one guide device so that the parallel shafts substantially vertically aligned at inner end portions of the shafts on the side of the rotary axis.
    Type: Grant
    Filed: October 13, 1995
    Date of Patent: March 31, 1998
    Assignee: Pioneer Electronic Corporation
    Inventors: Yuji Ikedo, Yoshifumi Masunaga, Kanya Matsumoto
  • Patent number: 5703864
    Abstract: An optical pickup device includes an objective lens assembly including an objective lens facing a surface of an optical disk, an actuator base supporting the objective lens to be movable, and a body in which an optical element is accommodated, the actuator base being supported by the body to be slidable. The actuator base is provided with a first flat portion positioned in a vicinity of the optical disk surface and a second flat portion apart from the optical disk surface, the first and second flat portions being formed with first and second protruded pieces having spherical end surfaces, and the body is formed with first and second receiving portions against which the first and second protruded pieces abut, respectively. The optical body is composed of a first supporting portion for supporting the first flat portion, a second supporting portion for supporting the second flat portion and an intermediate portion disposed below the first flat portion.
    Type: Grant
    Filed: March 29, 1996
    Date of Patent: December 30, 1997
    Assignee: Pioneer Electronic Corporation
    Inventors: Takahiro Miyagi, Shigeru Takaya, Yoshifumi Masunaga
  • Patent number: 5264968
    Abstract: A lens drive apparatus and its producing method are provided in which the productivity is improved and the assembly of components is conducted at high accuracy. In particular, a movable optical system containing an objective lens and a stationary base are coupled by elongated resilient members which serve as suspensions and are provided at both ends with joining members made of a resin material. The resilient members and the joining members are formed in combination by insertion-molding. Accordingly, their assembly can be executed so that troublesome work such as directly assembling the resilient members of delicate size is avoided, no exceptional skill is needed, and less steps are involved for ease of production, thus increasing the productivity. Also, the joining members are comparatively large in size and can thus be mounted at high positional accuracy to both the stationary base and the movable optical system.
    Type: Grant
    Filed: May 26, 1992
    Date of Patent: November 23, 1993
    Assignee: Pioneer Electronic Corporation
    Inventor: Yoshifumi Masunaga
  • Patent number: 5103438
    Abstract: An optical pickup device for applying controlled light to a track of an optical disc. Light orientation is controlled by changing the angular orientation of an objective lens mounted on a holder. The holder is disposed above an actuator base and is supported in a cantilevered manner by a suspension member fixed to the actuator base. The actuator base is mounted on a pickup body movable in a tracking direction of the disc. The holder is integrally coupled with a central portion of a yoke member, so that the yoke is also movable. The yoke member has inverted U-shaped portions provided symmetrically with respect to the central portion. Further, a pair of magnets are provided each being fixed to the outer surface of the central portion, i.e., a first inner surface of the inverted U-shaped portion, and a pair of coil members are fixed to the base. Each of the coil members is positioned within each of mangetic gaps defined by each free end of the inverted U-shaped portion and each of the magnets.
    Type: Grant
    Filed: March 13, 1989
    Date of Patent: April 7, 1992
    Assignee: Pioneer Electronic Corporation
    Inventors: Yoshifumi Masunaga, Yasuyuki Tashiro, Noboru Namigawara
  • Patent number: 5056891
    Abstract: An information reading apparatus generally comprises a body for accommodating optical elements such as a semiconductor laser, a photodiode and a prism, an objective lens disposed on a base of the body for reading information recorded in a recording medium, and an actuator means for positioning the objective lens with respect to a compact disk and actuating the objective lens in a direction along an optical axis thereof. In assembling the information reading apparatus, a base of the actuator means is mounted on the body, and an objective lens suspension body including an objective lens holder and a suspension base member connected thereto through a pair of bridge members is prepared by an injection molding. The bridge members are removed after the objective lens suspension body is mounted on the base of the actuator means.
    Type: Grant
    Filed: March 20, 1990
    Date of Patent: October 15, 1991
    Assignee: Pioneer Electronic Corporation
    Inventor: Yoshifumi Masunaga
  • Patent number: 4951277
    Abstract: In an optical disk player, the disk clamper magnet is so constructed as to prevent the resonance of the pickup actuator as the pickup approaches the inner circumference of the disk due to interaction between the clamper maagnet and actuator magnets as the clamper magnet rotates. This structure avoids the resonance problem which is especially prevalent when a pickup approaches an inner disk circumference during playing. Therefore, it is possible to prevent an increase in rate of occurrence of tracking errors or the like which hinder reproducing capability or even make the tracking servo inoperative in an extreme case.
    Type: Grant
    Filed: February 21, 1989
    Date of Patent: August 21, 1990
    Assignee: Pioneer Electronic Corporation
    Inventors: Yoshifumi Masunaga, Yoshitaka Simoda