Patents by Inventor Keizo Yamada

Keizo Yamada 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: 5913076
    Abstract: A house is two-dimensionally moved, and generates first and second analog signals representative of a movement in opposing first and second directions and another movement in opposing third and fourth directions that are perpendicular to the first and second directions. A data input device compares the first and second analog signals with a periodically changing reference signal to output a first pulse signal and a second pulse signal depending upon the comparison result, and selectively transfers a first pulse train and a second pulse train depending upon the duty factors of the first and second pulse signals so as to generate a composite digital signal representative of the motion of the mouse to a computer unit.
    Type: Grant
    Filed: March 28, 1997
    Date of Patent: June 15, 1999
    Assignee: Nec Corporation
    Inventor: Keizo Yamada
  • Patent number: 5874941
    Abstract: A presentation supporting device having excellent operability and adaptability to oral presentations in a computer multimedia environment. First and second accelerometers detect first and second acceleration of gravity resulting from inclinations in first and second sensitivity axis directions perpendicular to each other to output first and second acceleration signals, and first and second signal processors process the input first and second acceleration signals to output cursor moving control signals for controlling moving speeds and moving directions in the first and second coordinate axis directions of a cursor on a computer display screen in response to voltage values and polarities of the first and second acceleration signals.
    Type: Grant
    Filed: September 27, 1995
    Date of Patent: February 23, 1999
    Assignee: NEC Corporation
    Inventor: Keizo Yamada
  • Patent number: 5656846
    Abstract: An acceleration sensor is provided with damping means on an upper surface and/or an lower surface of a movable portion of a sensor body and/or opposite regions surrounded by the movable portion and a rim of the sensor body in order to provide damping of a vibration to the movable portion of the sensor body. The damping means includes a material having a large mechanical damping constant, for example, a plastic, a gel, an inorganic material, and micro capsules. In a fabrication process of the acceleration sensor, a supporting film is provided on the movable portion of the sensor body, the damping material is provided on the supporting film and the movable portion of the sensor body is subjected to etching so as to form a weight and a diaphragm.
    Type: Grant
    Filed: March 7, 1995
    Date of Patent: August 12, 1997
    Assignee: NEC Corporation
    Inventor: Keizo Yamada
  • Patent number: 5650688
    Abstract: A field emission cold cathode element having a conducting substrate, a dielectric layer which is on the substrate and has holes, emitter electrodes each of which have a sharp-pointed tip and stand on the substrate in the respective holes in the dielectric layer, and a gate electrode layer which is on the dielectric layer and has apertures right above the respective holes in the dielectric layer. The tip of each emitter electrode is near or in the aperture in the gate electrode layer, and the emission current depends on the position of the emitter tip relative to the gate electrode. The dielectric layer and the gate electrode layer are largely removed so as to remain only in limited first regions which are around the holes for the respective emitter electrodes and limited second regions each of which connects one of the first regions to another. The partial removal of the dielectric and gate electrode layers is for reducing interlayer stresses induced by temperature changes.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: July 22, 1997
    Assignee: NEC Corporation
    Inventors: Hideo Makishima, Keizo Yamada, Hironori Imura
  • Patent number: 5648698
    Abstract: A field emission cold cathode element having a conducting substrate, a dielectric layer which is on the substrate and has holes, emitter electrodes which have a sharp-pointed tip and stand on the substrate in the respective holes in the dielectric layer, and a gate electrode which is on the dielectric layer and has apertures right above the respective holes in the dielectric layer. The tip of each emitter electrode is near or in the aperture in the gate electrode layer. The dielectric layer is largely removed so as to remain only in limited regions around the holes for the respective emitter electrodes, and a gate electrode layer is formed with, in addition to the apertures for the emitter electrodes, a number of holes in regions where the substrate surface is exposed by removal of the dielectric layer. The partial removal of the dielectric and gate electrode layers has the effect of reducing interlayer stresses induced by temperature changes, so that the gate electrode layer can be made desirably thick.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: July 15, 1997
    Assignee: NEC Corporation
    Inventors: Hideo Makishima, Keizo Yamada, Hironori Imura
  • Patent number: 5635789
    Abstract: Disclosed is a field emission device which has an emitter formed in the center portion where ion bombardment is likely to occur, and a gate formed partially thicker, or which has a metal layer with the same potential as the emitter and a high melting point, formed in the center portion of the cathode. Therefore, even bombardment of positive ions at the center portion of the cold field emission device will not affect the electron emission, thereby ensuring an always stable cathode current or electron beam. Further, as the field emission device is designed to prevent the deterioration of the insulation between the emitter and gate, abrupt stopping of the electron emission hardly occurs. Therefore, an electron tube using this field emission device has a stable function and high reliability.
    Type: Grant
    Filed: December 30, 1994
    Date of Patent: June 3, 1997
    Assignee: NEC Corporation
    Inventors: Hideo Makishima, Keizo Yamada, Hironori Imura
  • Patent number: 5559390
    Abstract: The subject is a field emission cold cathode element having a conducting substrate, a dielectric layer which is on the substrate and has holes, emitter electrodes which have a sharp-pointed tip and stand on the substrate in the respective holes in the dielectric layer and a gate electrode layer which is on the dielectric layer and has apertures right above the respective holes in the dielectric layer. The tip of each emitter electrode is near or in the aperture in the gate electrode layer, and the emission current depends on the position of the emitter tip relative to the gate electrode. According to the invention, the gate electrode layer is made relatively thick in limited regions surrounding the respective apertures and relatively thin in other regions to compensate for inevitable variations in the emitter electrode heights without augmenting interlayer stresses attributed to different thermal expansions of the gate electrode and dielectric layers.
    Type: Grant
    Filed: April 12, 1994
    Date of Patent: September 24, 1996
    Assignee: NEC Corporation
    Inventors: Hideo Makishima, Keizo Yamada, Hironori Imura
  • Patent number: 5514847
    Abstract: A first laminated sub-structure having a semiconductor substrate, a lower insulating layer on the semiconductor substrate, emitter electrodes formed in micro-apertures in the lower insulating layer and a gate electrode on the upper surface of the lower insulating layer is aligned with a second laminated sub-structure having a transparent upper insulating layer and a grid member on the transparent upper insulating layer by means of a stepper, and the first and second laminated sub-structures are fixed to each other through a field assisted glass-metal sealing technique.
    Type: Grant
    Filed: January 24, 1994
    Date of Patent: May 7, 1996
    Assignee: NEC Corporation
    Inventors: Hideo Makishima, Keizo Yamada, Yoshinori Tomihari
  • Patent number: 5496199
    Abstract: A first laminated sub-structure having a semiconductor substrate, a lower insulating layer on the semiconductor substrate, emitter electrodes formed in micro-apertures in the lower insulating layer and a gate electrode on the upper surface of the lower insulating layer is aligned with a second laminated sub-structure having a transparent upper insulating layer and a grid member on the transparent upper insulating layer by means of a stepper, and the first and second laminated sub-structures are fixed to each other through a field assisted glass-metal sealing technique.
    Type: Grant
    Filed: May 23, 1995
    Date of Patent: March 5, 1996
    Assignee: NEC Corporation
    Inventors: Hideo Makishima, Keizo Yamada, Yoshinori Tomihari
  • Patent number: 5468972
    Abstract: A vacuum chamber is provided with an electron emission source on a first side wall, a collector on a second side wall opposite to the first side, and an insulated electrode on a bottom wall. Electrons emitted from the electron emission source move over the insulated electrode to be collected by the collector, so that the spatial position and the path of the electrons on the insulated electrode are controlled dependent on an electric potential generated by the insulated electrode.
    Type: Grant
    Filed: March 30, 1994
    Date of Patent: November 21, 1995
    Assignee: NEC Corporation
    Inventor: Keizo Yamada
  • Patent number: 5431050
    Abstract: An semiconductor acceleration sensor has an inner weight member supported by a supporting member through a pair of first torsion bars for converting a component force into displacement thereof and an outer weight member supported by the inner weight member through a pair of second torsion bars for converting another component force into displacement thereof, and the displacements are respectively converted into variations of capacitances of two pairs of capacitors, wherein one of the two pairs of capacitors is disposed at first areas where loops of a bidirectional rotation of the inner weight member and nodes of a bidirectional rotation of the outer weight member take place, and the other of the two pairs of capacitors is positioned at second areas where loops of the bidirectional rotation of the outer weight member and nodes of the bidirectional rotation of the inner weight member take place, thereby preventing the two pairs of capacitors from interference.
    Type: Grant
    Filed: December 17, 1993
    Date of Patent: July 11, 1995
    Assignee: NEC Corporation
    Inventor: Keizo Yamada
  • Patent number: 5404025
    Abstract: A semiconductor vacuum device including a semiconductor substrate 3, an insulator film 2 formed on the substrate 3, and a single crystal semiconductor film 1 formed on the insulator film 2. The single crystal semiconductor film 1 has a first and a second tapered edge opposite to one another but spaced apart over a gap formed in the insulator film 2. The first tapered edge acts 6 as a cathode and the second tapered edge acts as a gate 7, the substrate 1 acting as an anode into which said electrons emitted from the cathode above.
    Type: Grant
    Filed: April 23, 1993
    Date of Patent: April 4, 1995
    Assignee: NEC Corporation
    Inventor: Keizo Yamada
  • Patent number: 5396439
    Abstract: An output signal of an acceleration sensor is supplied to a DC amplifier to thereby generate an acceleration output. A low frequency component of the acceleration output of the DC amplifier is negatively fed back by a feedback circuit to the input of the DC amplifier.
    Type: Grant
    Filed: August 12, 1992
    Date of Patent: March 7, 1995
    Assignee: NEC Corporation
    Inventor: Keizo Yamada
  • Patent number: 5081867
    Abstract: A semiconductor sensor comprising a semiconductor sensor member provided on a support member. The sensor member has a base portion and a rim portion connected to each other by a beam portion. The base portion is fixed to the support member and the rim portion is held by the beam portion such that the rim portion is spaced apart from the base portion and the support portion. The beam portion is provided with a resistor to detect the changes of resistance values of the resistor due to mechanical stress caused at the beam portion.
    Type: Grant
    Filed: October 2, 1989
    Date of Patent: January 21, 1992
    Assignee: NEC Corporation
    Inventor: Keizo Yamada
  • Patent number: 4525209
    Abstract: A process for producing a low P chromium-containing steel in an AOD vessel from a high P chromium-containing molten pig iron comprising a first stage of recarborization, desiliconzation and temperature raising, a second stage of dephosphorization with slag, which may be repeated, and a third stage of conventional refining.
    Type: Grant
    Filed: May 2, 1984
    Date of Patent: June 25, 1985
    Assignees: Pacific Metals & Co. Ltd., Nisshin Steel Co. Ltd.
    Inventors: Takashi Yamauchi, Shigeaki Maruhashi, Shinkichi Koike, Keizo Yamada