Patents by Inventor Yoshitaka Itoh

Yoshitaka Itoh 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: 6109751
    Abstract: The structure of the present invention makes dark lines due to a central axis of a cross dichroic prism sufficiently inconspicuous. A stepped reflecting mirror is interposed between a second lens array and a condenser. The stepped reflecting mirror has the function of deviating the optical path of part of the partial light fluxes among a plurality of partial light fluxes passing through a plurality of small lenses aligned on the same column in lens arrays from the optical path of the other partial light fluxes. A planar transparent member may be used in place of the stepped reflecting mirror for the purpose of deviating the optical path. Another technique shifts part of rows in the lens arrays and to deviate the optical path of part of the partial light fluxes.
    Type: Grant
    Filed: June 26, 1998
    Date of Patent: August 29, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Toshiaki Hashizume, Yoshitaka Itoh
  • Patent number: 6111490
    Abstract: A cold head is disposed in an insulating container and cooled by a refrigerator. A superconductor is disposed in the insulating container, contacting the cold head, and is cooled to its superconduction transition temperature or lower by heat conduction. A magnetizing coil is disposed outside the insulating container for applying a magnetic field to the superconductor. Control is performed so that a magnetic field determined considering the magnetic field to be captured by the superconductor is applied. A pulsed magnetic field is applied to the superconductor a plurality of times. Each pulsed magnetic field is applied when the temperature of the superconductor is a predetermined temperature or lower. A maximum pulsed magnetic field is applied at least once in an initial or intermediate stage of the repeated application of pulsed magnetic fields. After that, a pulsed magnetic field equal to or less than the maximum pulsed magnetic field is applied.
    Type: Grant
    Filed: June 19, 1997
    Date of Patent: August 29, 2000
    Assignee: Aisin Seiki Kabushiki Kaisha
    Inventors: Yousuke Yanagi, Tetsuo Oka, Yoshitaka Itoh, Masaaki Yoshikawa
  • Patent number: 6109752
    Abstract: The present invention provides a lighting device that has two lamp units and is suitable for a light source of a projector-type display apparatus to realize bright illumination, and also a projector-type display apparatus with such a lighting device incorporated therein. The lighting device includes a light source unit and an integrator optical system and enables an illumination area to be illuminated uniformly and evenly with the light emitted from the light source unit and transmitted via the integrator optical system. The light source unit includes a pair of lamp units arranged in parallel, and a reflector of each lamp unit has a contour with both sides cut off. The pair of lamp units are preferably arrayed in a direction perpendicular to a longitudinal direction of the illumination area. This structure realizes a small-sized, compact lighting device with a high quantity of output light.
    Type: Grant
    Filed: April 27, 1998
    Date of Patent: August 29, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Yoshitaka Itoh, Toshiaki Hashizume
  • Patent number: 6108132
    Abstract: In a polarization illuminating device 1, random polarized light emitted from first and second light source sections 101x and 101z is separated into two types of polarized light by a polarization separation section 202, and then secondary light source images deviated in the x-direction are formed, with the directions of polarization being aligned. First through third converging mirror plates 1001x, 1002 and 1001z are obliquely arranged so that, in the light emitted from the first and second light source sections 101x and 101z, the secondary light source images due to the S-polarized light may be superimposed one upon the other, and the secondary light source images due to the P-polarized light may be superimposed one upon the other. Thus, a polarization illuminating device capable of utilizing both polarization components is provided without entailing an increase in the area of the light source image although a plurality of light sources are used.
    Type: Grant
    Filed: April 16, 1998
    Date of Patent: August 22, 2000
    Assignee: Seiko Epson Corporation
    Inventor: Yoshitaka Itoh
  • Patent number: 6101040
    Abstract: An upper portion and lower portion of a first lens array may be relatively offset from each other in an x direction. A second lens array is also offset correspondingly to the first lens array. Since an angle at which a partial light beam transmitted through the upper portions of the first and second lens arrays illuminates an area of illumination is different from an angle at which a partial light beam transmitted through the lower portions of the first and second lens arrays illuminates the area of illumination, dark lines generated by these partial light beams appear in different positions on a screen. With this arrangement, the dark lines resulting from the center line of a cross-dichroic prism are made less visible.
    Type: Grant
    Filed: March 30, 1998
    Date of Patent: August 8, 2000
    Assignee: Seiko Epson Corporation
    Inventor: Yoshitaka Itoh
  • Patent number: 6042234
    Abstract: A polarized light illumination device that is able to utilize both polarized light components by using a plurality of light sources without increasing the illumination angle, and a projection display device that is able to project a considerably bright projection image are provided. In a polarized light illumination device, randomly polarized light emitted from first and second light sources is directionally separated into two types of polarized light by a polarized light separating and synthesizing optical element, secondary light-source images, which are offset in the x direction, are formed, and then, the direction of polarization is aligned.
    Type: Grant
    Filed: February 17, 1999
    Date of Patent: March 28, 2000
    Assignee: Seiko Epson Corporation
    Inventor: Yoshitaka Itoh
  • Patent number: 6036318
    Abstract: A projection type display apparatus 1 is roughly composed of a polarized light beam illumination device 100, a polarization beam splitter 200, a reflection type liquid crystal device 300, and a projection optical system 500. The polarized light beam illumination device 100 includes a light source unit 110, a first optical element 120 and a second optical element 130, and the light beams emerging from the light source unit 110 are divided into a plurality of intermediate light beams by the first optical element 120 and thereafter converted into polarized light beams having approximately one kind of a polarization direction by the second optical element 130. The polarized light beams are reflected at the polarization beam splitter 200 and modulated by the reflection type liquid crystal device 300 and thereafter projected to a projection surface 600 through the projection optical system 500.
    Type: Grant
    Filed: January 27, 1998
    Date of Patent: March 14, 2000
    Assignee: Seiko Epson Corporation
    Inventor: Yoshitaka Itoh
  • Patent number: 5986809
    Abstract: A polarizing conversion device in accordance with the invention includes a first optical element for condensing an incident beam and forming a plurality of intermediate beams spatially separated from one another, and a second optical element for spatially separating each intermediate beam into two polarized beams and aligning the polarization directions of the polarized beams, thereby obtaining the same type of polarized beams. In the second optical element, a shading plate is placed to prevent light from directly entering a section corresponding to a reflecting plane of a polarizing separation unit array. Since the ability of separating the intermediate beam into two polarized beams is thereby enhanced, it is possible to perform conversion into the same type of polarized beams polarized in the same direction, with high efficiency.
    Type: Grant
    Filed: February 20, 1998
    Date of Patent: November 16, 1999
    Assignee: Seiko Epson Corporation
    Inventors: Yoshitaka Itoh, Toshiaki Hashizume
  • Patent number: 5981442
    Abstract: An Nd-Ba-Cu-O bulk superconductor includes oxide including metallic elements of neodymium (Nd), barium (Ba) and copper (Cu), and has a structure in which fine particles of Nd.sub.4 Ba.sub.2 Cu.sub.2 O.sub.10 (i.e., Nd422) are dispersed uniformly in crystalline grains of NdBa.sub.2 Cu.sub.3 O.sub.x (i.e., Nd123). It is produced by preparing a mixture powder in which an Nd123 powder and an Nd422 powder are present uniformly, thermally treating the mixture powder in a temperature range where the Nd123 powder melts partially at least but the Nd422 powder hardly melts, and gradually cooling the partially melted mixture powder in a temperature range around a solidifying point of the Nd123 powder. It exhibits an enhanced magnetic-field-trapping capability in the regions of low magnetic field, because of the pinning effect resulting from the fine particles of Nd422 dispersed uniformly in the crystalline grains of Nd123.
    Type: Grant
    Filed: September 14, 1998
    Date of Patent: November 9, 1999
    Assignee: Aisin Seiki Kabushiki Kaisha
    Inventors: Yousuke Yanagi, Takeo Yamazaki, Atsushi Takagi, Yuh Yamada, Uichiro Mizutani, Yoshitaka Itoh, Masaaki Yoshikawa, Tetsuo Oka
  • Patent number: 5973840
    Abstract: An apparatus which makes dark lines due to a central axis of a cross dichroic prism sufficiently inconspicuous. In a second lens array, minute lenses arranged on the same column include three different types of minute lenses having optical axes at different positions. Each row of the minute lenses consists of one of the three types of minute lenses. Partial light fluxes respectively passing through the minute lenses have optical axes at different positions relative to a center of a lighting area of a liquid-crystal light bulb, so as to illuminate different illumination areas.
    Type: Grant
    Filed: June 29, 1998
    Date of Patent: October 26, 1999
    Assignee: Seiko Epson Corporation
    Inventors: Yoshitaka Itoh, Toshiaki Hashizume
  • Patent number: 5626409
    Abstract: A projection-type display apparatus includes a light source, a uniform illumination optical system, a color separating system for separating a white light beam emitted from the uniform illumination optical system into three color beams, three liquid crystal panels for respectively modulating each of the separated color beams, a light guide system located on an optical path of the color beam having the longest optical path among the separated color beams, a dichroic prism for synthesizing the beams modulated through the liquid crystal panels, and a projection lens for projecting the synthesized and modulated beam onto a screen. The uniform illumination optical system is provided with a uniform illumination optical device for converting the white light beam emitted from the light source into a uniform rectangular beam.
    Type: Grant
    Filed: January 4, 1995
    Date of Patent: May 6, 1997
    Assignee: Seiko Epson Corporation
    Inventors: Tadaaki Nakayama, Yoshitaka Itoh, Akitaka Yajima
  • Patent number: 5440424
    Abstract: A polarizer optical device for receiving and transmitting light is provided. The polarizer optical device includes a light separating section for separating the light into two polarization components which are othogonal with respect to one another. Further, the optical device is provided with a polarization rotating section for rotating the two polarization components so that a phase difference between the two polarization components othogonal to each other is 1/2.lambda.. Finally, a light combining section is provided for combining the light into a outputted light beam. The light combining section may be formed with a combination of birefringent prisms and isotropic mediums interfacing one another. In these configurations, the refractive index of each prism or medium is selected so that an angle formed with two unparallel incident lights differs from an angle formed with two output or transmitted lights.
    Type: Grant
    Filed: February 18, 1993
    Date of Patent: August 8, 1995
    Assignee: Seiko Epson
    Inventors: Jin-Jei Wu, Shoichi Uchiyama, Yoshitaka Itoh, Tomio Sonehara
  • Patent number: 4970487
    Abstract: A sensor is provided for detecting a physical quantity such as fluid pressure and acceleration of a mass and converting same into electrical signals. The sensor has a diaphragm made of a metal deformable by the physical quantity, a layered constructed insulating means of an insulating material which is formed on the diaphragm by means of a physical vapor desposition process, wherein the layered constructed insulating means has at least two insulating material layers, a strain gauge formed on the layered constructed insulating means opposite the diaphragm by means of a physical vapor deposition process, and a contact zone on the strain gauge to provide an electrical connection for a physical quantity sensing device to the sensor. Due to the layered construction of the insulating means, the thickness of the insulating means as a whole may be reduced below that of a single layer insulating means and maintain good insulative properties particularly at excessive strain.
    Type: Grant
    Filed: December 12, 1988
    Date of Patent: November 13, 1990
    Assignee: Aisin Seiki Kabushiki Kaisha
    Inventors: Makoto Tsukahara, Yukihiro Kato, Yoshitaka Itoh, Tetsuo Oka
  • Patent number: 4680046
    Abstract: A method of preparing preforms for optical fibers is provided. The method includes preparation of a first sol solution of a silicon alkoxide hydrolyzed with an acid and ultrafine particle silica, placement of the first sol solution into a container, and gelation of the first sol solution while the container is being rotated to yield a wet gel having a center hole. A second sol solution having a different composition than the first sol solution is prepared and used to fill the center hole in the wet gel. The second sol solution is then gelled to a wet gel composite and the composite is dried and sintered to yield the preform.
    Type: Grant
    Filed: October 2, 1985
    Date of Patent: July 14, 1987
    Assignee: Seiko Epson Kabushiki Kaisha
    Inventors: Nobutaka Matsuo, Masanobu Motoki, Yoshitaka Itoh, Sadao Kanbe, Haruo Osafune
  • Patent number: 4680048
    Abstract: A sol-gel method of preparing doped glass articles is provided. The glass is formed by preparing a sol solution containing hydrolyzed silicon alkoxide and ultrafine particle silica. The sol solution can also include a dopant. The sol solution is gelled in a container, dried and sintered to yield the doped silica glass articles.
    Type: Grant
    Filed: October 1, 1985
    Date of Patent: July 14, 1987
    Assignee: Seiko Epson Kabushiki Kaisha
    Inventors: Masanobu Motoki, Nobutaka Matsuo, Sadao Kanbe, Haruo Osafune, Yoshitaka Itoh
  • Patent number: 4622056
    Abstract: A method for preparing high quality silica glass articles is provided. The glass is prepared by hydrolyzing silicon alkoxide with a basic reagent to yield a first solution, hydrolyzing a silicon alkoxide with an acid reagent to yield a second solution, mixing the first solution with the second solution at a predetermined mixing rate to yield a sol solution, pouring the sol solution into a container, gelling the sol solution to a wet gel, drying the wet gel to a dry gel, and sintering the dry gel to yield a silica glass.
    Type: Grant
    Filed: February 6, 1986
    Date of Patent: November 11, 1986
    Assignee: Seiko Epson Corporation
    Inventors: Nobutaka Matsuo, Yoshitaka Itoh, Sadao Kanbe, Haruo Osafune, Masanobu Motoki
  • Patent number: 4197623
    Abstract: A factory barge for manufacturing reinforced concrete products comprises a batcher plant mounted at one end of the hull for preparing ready mixed concrete, a reinforced concrete product unloader mounted at the opposite end of the hull, and, between the batcher plant and the unloader, in the order mentioned, concrete placers for receiving the concrete from the batcher plant and placing it into elongated molds held in the fore-and-aft direction, compactors for compacting the concrete in the molds, a curer for curing the concrete compacted in the molds, and a mold remover for removing the molds from the cured concrete products. An equipment for fabricating reinforcement cylinders is mounted on a deck above the deck where the concrete placers are installed, and means for transferring the molds from the concrete placers to the compactors, curer, and mold remover is so disposed as to handle the molds while maintaining them in the fore-and-aft direction.
    Type: Grant
    Filed: April 4, 1978
    Date of Patent: April 15, 1980
    Assignees: Mitsubishi Jukogyo Kabushiki Kaisha, Daido Concrete Co., Ltd., Shimizu Harbor Const. Corp.
    Inventors: Toshimasa Suzuki, Chiaki Matsuyama, Susumu Ogawa, Yoshitaka Itoh, Yasuo Usui