Patents by Inventor Katsuhiko Kenjo

Katsuhiko Kenjo 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: 6629371
    Abstract: A surveying instrument which incorporates a magnetic incremental rotary encoder includes a rotary magnetic drum provided on an outer peripheral surface thereof with a multi-pole magnetized layer having a plurality of equally-divided magnetized divisions, a pair of magnetic sensors located on opposite sides of said rotary magnetic drum so that each of said pair of magnetic sensors faces said multi-pole magnetized layer, and at least one magnet, positioned in the vicinity of at least one of said pair of magnetic sensors, for reducing an error in detection of said magnetic incremental rotary encoder.
    Type: Grant
    Filed: October 20, 2000
    Date of Patent: October 7, 2003
    Assignees: Pentax Corporation, Pentax Precision Co., Ltd.
    Inventors: Masami Shirai, Katsuhiko Kenjo
  • Patent number: 6622391
    Abstract: An incremental rotary encoder includes a rotary portion, a first sensor and a second sensor, the first and second sensors being arranged so as to be opposite from each other with respect to the axis of the rotary portion. The second sensor is offset from the first sensor so that the phase of output voltage of the second sensor advances or delays with respect to the phase of output voltage of the first sensor by &pgr;/X, wherein “X” represents a real number of one or more than one.
    Type: Grant
    Filed: April 27, 2000
    Date of Patent: September 23, 2003
    Assignees: Pentax Corporation, Pentax Precision Co., Ltd.
    Inventors: Masami Shirai, Masato Noguchi, Katsuhiko Kenjo
  • Patent number: 6555809
    Abstract: An incremental rotary encoder having first and second sensors which each output two sine wave signals having a phase difference of 90 degrees while a rotary member of the incremental rotary encoder rotates. The incremental rotary encoder includes an absolute-zero-index detecting device, provided for the first sensor; at least one binary coding circuit which codes each of the two sine wave signals and the zero index signal into a corresponding binary signal; a holding device for holding the level data of the binary signal of each sine wave signal output from the second sensor when the absolute-zero-index detecting device outputs the zero index signal; and a controller for determining whether the phase of the two sine wave signals output from the second sensor advances or delays with respect to the phase of the two sine wave signals output from the first sensor.
    Type: Grant
    Filed: March 26, 2002
    Date of Patent: April 29, 2003
    Assignees: Pentax Corporation, Pentax Precision Co., Ltd.
    Inventors: Katsuhiko Kenjo, Masami Shirai
  • Patent number: 6550150
    Abstract: A surveying instrument which incorporates a magnetic incremental rotary encoder includes a rotary magnetic drum provided on an outer peripheral surface thereof with a multi-pole magnetized layer having a plurality of equally-divided magnetized divisions; and at least two magnetic sensors, each of which detects a magnetic field generated by the multi-pole magnetized layer therefrom. Each of the at least two magnetic sensors detects a variation in the magnetic field due to a rotation of the rotary magnetic drum to measure an angle of rotation of the rotary magnetic drum, and the at least two magnetic sensors are arranged so that two of the at least two magnetic sensors are offset from each other to have a phase angle of an odd-numbered pitch angle therebetween.
    Type: Grant
    Filed: October 20, 2000
    Date of Patent: April 22, 2003
    Assignees: Pentax Corporation, Pentax Precision Co., Ltd.
    Inventors: Masami Shirai, Katsuhiko Kenjo
  • Publication number: 20020153479
    Abstract: An incremental rotary encoder having first and second sensors which each output two sine wave signals having a phase difference of 90 degrees while a rotary member of the incremental rotary encoder rotates. The incremental rotary encoder includes an absolute-zero-index detecting device, provided for the first sensor; at least one binary coding circuit which codes each of the two sine wave signals and the zero index signal into a corresponding binary signal; a holding device for holding the level data of the binary signal of each sine wave signal output from the second sensor when the absolute-zero-index detecting device outputs the zero index signal; and a controller for determining whether the phase of the two sine wave signals output from the second sensor advances or delays with respect to the phase of the two sine wave signals output from the first sensor.
    Type: Application
    Filed: March 26, 2002
    Publication date: October 24, 2002
    Applicant: ASAHI KOGAKU KOGYO KABUSHIKI KAISHA
    Inventors: Katsuhiko Kenjo, Masami Shirai
  • Patent number: 6384405
    Abstract: An incremental rotary encoder having first and second sensors which each output two sine wave signals having a phase difference of 90 degrees while a rotary member of the incremental rotary encoder rotates. The incremental rotary encoder includes an absolute-zero-index detecting device, provided for the first sensor; at least one binary coding circuit which codes each of the two sine wave signals and the zero index signal into a corresponding binary signal; a holding device for holding the level data of the binary signal of each sine wave signal output from the second sensor when the absolute-zero-index detecting device outputs the zero index signal; and a controller for determining whether the phase of the two sine wave signals output from the second sensor advances or delays with respect to the phase of the two sine wave signals output from the first sensor.
    Type: Grant
    Filed: April 27, 2000
    Date of Patent: May 7, 2002
    Assignees: Asahi Kogaku Kogyo Kabushiki Kaisha, Asahi Seimitsu Kabushiki Kaisha
    Inventors: Katsuhiko Kenjo, Masami Shirai
  • Patent number: 6304079
    Abstract: An incremental rotary encoder outputs two sine wave signals having a phase difference of 90 degrees when the incremental rotary encoder is in operation, the incremental rotary encoder including a binary coding circuit which codes each of the two sine wave signals into a binary signal, a voltage detector which detects the voltage of one of the two sine wave signals at the moment of variation in a signal level of the binary signal, and a controller which includes a calculator which takes an even number of voltage values from each of the two sine wave signals to take an average of the even number of voltage values for each of the two sine wave signals.
    Type: Grant
    Filed: April 27, 2000
    Date of Patent: October 16, 2001
    Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
    Inventors: Katsuhiko Kenjo, Masami Shirai