Patents by Inventor Takahiro Numai

Takahiro Numai 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: 6833549
    Abstract: An electric field is applied to a charge emitting layer. The charge emitting layer absorbs radioactive rays generated by a radiation source, converts the rays into electric charges, and emits the converted charges. The electric field has an intensity satisfying a lower limit of a specification value of a carrier capturing efficiency and an upper limit of a specification value of a dark current density. A dark current at a trap level can be lowered, a carrier capturing efficiency can be improved, and radioactive rays can be detected with small noises and at a high sensitivity. It is possible to reliably detect incident radioactive rays and form an image of incident radioactive rays.
    Type: Grant
    Filed: November 21, 2002
    Date of Patent: December 21, 2004
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takahiro Numai, Masakazu Morishita
  • Patent number: 6785003
    Abstract: A semiconductor ring laser gyro comprising two or more ring lasers, the ring lasers being optically independent of each other, is characterized in that a change in beat frequency with respect to a change in angular velocity of a first ring laser is opposite to that of a second ring laser, and angular velocity of rotation of the gyro is detected by a signal representing a difference between a first beat frequency generated by the first ring laser and a second beat frequency generated by the second ring laser.
    Type: Grant
    Filed: July 10, 2001
    Date of Patent: August 31, 2004
    Assignee: Canon Kabushiki Kaisha
    Inventors: Natsuhiko Mizutani, Takahiro Numai
  • Patent number: 6741354
    Abstract: A gyro comprising a laser device for generating laser beams to be propagated circuitally in opposite directions, wherein an electric signal is taken out from the laser device, the oscillation frequencies of the laser beams being different from each other when the laser device is held stationary.
    Type: Grant
    Filed: January 18, 2000
    Date of Patent: May 25, 2004
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Patent number: 6665330
    Abstract: A semiconductor device having a semiconductor ring laser and a base member with an electrode. The semiconductor ring laser has a circularly formed ridge optical waveguide. A concave region exists at the inside or outside of the waveguide. An electrode layer is provided over the waveguide and concave region, and the electrode and the electrode layer are electrically connected to each other through a conductive member existing in the concave region.
    Type: Grant
    Filed: September 11, 2000
    Date of Patent: December 16, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Patent number: 6656759
    Abstract: A method of producing a semiconductor element is disclosed which comprises a step of preparing a semiconductor element member comprising a projection region on a substrate, a step of embedding an upper surface of the substrate, and upper and side surfaces of the projection region in a potting material, an exposure step of exposing the upper surface of the projection region, a deposition step of depositing an electrode material on the upper surface of the projection region, and a step of removing the potting material.
    Type: Grant
    Filed: May 18, 2000
    Date of Patent: December 2, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventors: Koichiro Nakanishi, Takahiro Numai
  • Patent number: 6658039
    Abstract: A ring laser of the present invention includes multiple ring resonators with different optical path lengths, wherein at least part of the multiple ring resonators is optically coupled, and a propagating direction of laser light propagating in the ring resonators is not reversed by the coupling.
    Type: Grant
    Filed: July 10, 2001
    Date of Patent: December 2, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Patent number: 6639680
    Abstract: To make a time averaged value of a driving current small. After a current I1 of a first current value not less than an oscillation threshold is injected to a semiconductor laser gyro, a current I2 of a second current value smaller than the first current value is injected.
    Type: Grant
    Filed: November 9, 2000
    Date of Patent: October 28, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Patent number: 6631002
    Abstract: A ring laser gyro wherein a first and a second laser beam propagate with propagating directions different with each other comprises electrode areas on an optical waveguide configuring the ring laser and controls an current injected or a voltage applied to the electrode areas, wherein the oscillating frequencies of the first and second laser beams are different from each other, thereby causing an increase and a decrease in the beat frequency enabling to detect the direction and the speed of a rotation at the same time. With regards to a method for detecting a rotation, the anode of the laser gyro is connected to an operational amplifier. Since the signal outputted from the operational amplifier has a frequency corresponding to the angular speed, it is converted into the voltage by a frequency-voltage conversion circuit so as to detect a rotation. This same method can be used for other types of gyros such as a semiconductor laser gyro, a gas lager gyro and the like.
    Type: Grant
    Filed: November 6, 2000
    Date of Patent: October 7, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Publication number: 20030155517
    Abstract: The invention is to realize a radiation detecting element of an excellent sensitivity to the incident radiation, and to provide a radiation image pickup apparatus showing a low dark current generating noises and having a satisfactory resolution. A carrier diffusion preventing layer is provided between a charge emitting layer 20 and at least either of a 10 first semiconductor layer and a second semiconductor layer 20 to prevent a carrier diffusion from such either semiconductor layer to the charge emitting layer, thereby reducing the dark current caused by the trap level. It is thus possible to improve the carrier capture efficiency and to realize the radiation detecting element of a high sensitivity.
    Type: Application
    Filed: February 20, 2003
    Publication date: August 21, 2003
    Applicant: Canon Kabushiki Kaisha
    Inventors: Takahiro Numai, Masakazu Morishita
  • Patent number: 6603113
    Abstract: A gyro apparatus has a ring laser in which laser beams of different oscillation frequencies coexist and propagate in mutually opposite circulation directions in an optical resonator, a power source of driving for the ring laser, a device for measuring a difference between the oscillation frequencies of the laser beams, and a device for controlling the power source of driving according to the frequency difference.
    Type: Grant
    Filed: July 5, 2001
    Date of Patent: August 5, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Publication number: 20030127599
    Abstract: An electric field is applied to a charge emitting layer. The charge emitting layer absorbs radioactive rays generated by a radiation source, converts the rays into electric charges, and emits the converted charges. The electric field has an intensity satisfying a lower limit of a specification value of a carrier capturing efficiency and an upper limit of a specification value of a dark current density. A dark current at a trap level can be lowered, a carrier capturing efficiency can be improved, and radioactive rays can be detected with small noises and at a high sensitivity. It is possible to reliably detect incident radioactive rays and form an image of incident radioactive rays.
    Type: Application
    Filed: November 21, 2002
    Publication date: July 10, 2003
    Inventors: Takahiro Numai, Masakazu Morishita
  • Patent number: 6586725
    Abstract: An optical gyro is provided with a ring laser and detection unit for detecting the beat frequency of said ring laser, and comprises a first ring laser of which beat frequency decreases when the angular velocity increases in a certain direction from a standstill state and a second ring laser of which beat frequency increases when the angular velocity increases regardless of the rotating direction. The first and second ring lasers are so positioned as to be mutually independent optically.
    Type: Grant
    Filed: July 10, 2001
    Date of Patent: July 1, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventors: Natsuhiko Mizutani, Takahiro Numai
  • Patent number: 6566155
    Abstract: A method of manufacturing a semiconductor device comprising the steps of preparing a member having at least one semiconductor layer on a substrate, forming an electrode layer on the semiconductor layer, forming an etching mask on the electrode layer, and forming a mesa profile by etching the electrode layer and the semiconductor layer.
    Type: Grant
    Filed: April 18, 2000
    Date of Patent: May 20, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Patent number: 6559949
    Abstract: A gyro comprises a first laser adapted to generate a first laser beam propagating in a single direction as a main mode of operation, and a second laser adapted to generate a second laser beam propagating in a single direction as a main mode of operation. The gyro may have a beat signal detection means and a photodetector for receiving the first and second laser beams. The first laser beam and the second laser beam have different respective oscillation frequencies and interfere with each other.
    Type: Grant
    Filed: January 21, 2000
    Date of Patent: May 6, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Patent number: 6501776
    Abstract: A semiconductor laser includes a substrate, semiconductor layers formed on the substrate, which construct a cavity including a waveguide with an active region and include at least one semiconductor layer whose refractive-index temperature coefficient is set at a non-positive or minute value sufficient to achieve at least one of the functions of stabilizing an oscillation wavelength of the semiconductor laser and suppressing an overflow of carriers from the active region, and a driving unit for causing electron-hole recombination in the active region.
    Type: Grant
    Filed: January 27, 2000
    Date of Patent: December 31, 2002
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Patent number: 6493089
    Abstract: An optical gyro reduces the coupling loss produced when a laser beam is incident upon a photodetector and the noise generated by the laser beam returning to the laser from an external point of reflection. The gyro includes a ring resonator type semiconductor laser for having laser beams transmitted circularly in opposite directions relative to each other. The angle &agr; formed by the surface of the active layer of the semiconductor laser and the lateral surface of each of the low refractive index layers sandwiching the active layer and showing a refractive index lower than the active layer satisfies the requirement of 75°<a<105° over the entire periphery of the low refractive index layer. The gyro detects a beat signal generated in the semiconductor laser.
    Type: Grant
    Filed: October 18, 1999
    Date of Patent: December 10, 2002
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Publication number: 20020176087
    Abstract: A gyro comprising a laser device for generating laser beams to be propagated circuitally in opposite directions, wherein an electric signal is taken out from the laser device, the oscillation frequencies of the laser beams being different from each other when the laser device is held stationary.
    Type: Application
    Filed: January 18, 2000
    Publication date: November 28, 2002
    Inventor: TAKAHIRO NUMAI
  • Patent number: 6448552
    Abstract: A gyro comprises a ring resonator type laser, a vibration table for applying an oscillation to the laser, and a signal processor for processing an output signal from the laser. The signal processor determines the phase angle of the output signal from the amplitude of an oscillation cycle component of the vibration table and that of a higher harmonic component thereof.
    Type: Grant
    Filed: March 14, 2000
    Date of Patent: September 10, 2002
    Assignee: Canon Kabushiki Kaisha
    Inventors: Natsuhiko Mizutani, Takahiro Numai
  • Patent number: 6445454
    Abstract: A gyro and an operating method is capable of reducing coupling losses which arise when laser beams enter a photodetector and noise which develops due to light entering into a laser from external reflection points. The gyro includes a ring resonator type laser in which laser beams circularly counter propagate, and detects a change in a current or an impedance based on a beat which is generated by the interference of the laser beams counter propagating each other within the laser.
    Type: Grant
    Filed: October 18, 1999
    Date of Patent: September 3, 2002
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takahiro Numai
  • Publication number: 20020048023
    Abstract: A gyro and an operating method therefor, capable of reducing coupling losses which arise when laser beams enter a photodetector, and noise which develops due to light entering into a laser from external reflection points. A gyro according to the present invention comprises a ring resonator type laser in which laser beams circularly counter propagate, and it detects a change in a current or an impedance based on a beat which is generated by the interference of the laser beams counter propagating each other within the laser.
    Type: Application
    Filed: October 18, 1999
    Publication date: April 25, 2002
    Inventor: TAKAHIRO NUMAI