Using Phase Difference Of Output Signals From Plural Photodetectors Patents (Class 250/231.16)
  • Patent number: 6396052
    Abstract: A method of determining a feed position of a print medium in an imaging apparatus includes an encoder device, connected to a feed shaft, that produces a first periodic signal and a second periodic signal approximately 90 degrees out of phase with the first. A modified first signal is created. A modified second signal is created. The modified first signal is added to the modified second signal to create a summation signal that has a plurality of local minimum values, a plurality of local maximum values, and a plurality of substantially linear segments. A periodic modified summation signal is created by adding a corresponding constant value to each linear segment. The feed position of the print medium is calculated based upon a number of cycles of the modified summation signal counted and a determined value of the modified summation signals.
    Type: Grant
    Filed: April 7, 2000
    Date of Patent: May 28, 2002
    Assignee: Lexmark International, Inc.
    Inventors: Raymond Jay Barry, Todd Alan Dutton, Steven Andrew Rice
  • 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
  • Publication number: 20020000515
    Abstract: It is an object of this invention to provide a mold for manufacturing an optical scale which can be easily manufactured and is capable of outputting high-precision position signals. In order to achieve this object, there is provided a mold for an optical scale, which has fixed and movable platens and is used to mold an optical scale, wherein both a first mold portion for forming a shaft mount hole for the optical scale and a second mold portion for forming a slit portion of the optical scale are arranged in one of the fixed and movable platens.
    Type: Application
    Filed: April 11, 2001
    Publication date: January 3, 2002
    Inventors: Manabu Takayama, Masahiko Igaki
  • Patent number: 6330522
    Abstract: A rotor is fixed to a steering shaft to rotate with the steering shaft, and outer and inner slits are formed along different circles on the rotor. Outer and inner sensors, which detect the presence or absence of the slits, generate reflective codes and are located next to the rotor. Stored pattern data that matches the reflective code is used to determine the rotational angle. Alternatively, if the pattern data does not match the reflective codes, the rotational angle of the steering shaft is computed on the basis of the reflective codes.
    Type: Grant
    Filed: September 16, 1999
    Date of Patent: December 11, 2001
    Assignee: Kabushiki Kaisha Tokai Rika Denki Seisakusho
    Inventor: Shuichi Takeuchi
  • Patent number: 6323786
    Abstract: An absolute-value encoder device for detecting a plurality of rotation quantities is disclosed. An A/B phase forming portion 610 forms an A-phase pulse signal and a B-phase pulse signal, based on light passing through a slit rotating together with a rotary shaft. One period of each of those pulse signals corresponds to one revolution of a rotary shaft. The A- and B-phase pulse signals are displaced in phase by 90° from each other. When an A/B-phase state detecting portion 640 detects a state change of each of those pulse signals, a clock forming portion 66 changes a frequency of a clock pulse signal to another frequency.
    Type: Grant
    Filed: October 25, 2000
    Date of Patent: November 27, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hirokazu Sakuma, Takashi Okamuro, Yoichi Ohmura, Yukio Aoki, Toshikazu Satone
  • Patent number: 6285023
    Abstract: In a linear scale, a reference point signal is outputted as a signal which is synchronized with an absolute value. 8 is a a/b phase signal generator forming a two-phase a/b signal of a moving signal by an absolute value which divided the inside of pitch when the a scale moves, 31 is a period counter, 32 is a subtracter, 33 is an up-down counter.
    Type: Grant
    Filed: March 10, 1999
    Date of Patent: September 4, 2001
    Assignee: Futaba Denshi Kogyo Kabushiki Kaisha
    Inventor: Takahisa Uehira
  • Patent number: 6255644
    Abstract: An optical rotary encoder simple in construction and capable of easily securing an aligned state of a code plate with a rotating shaft A disk DS and an attachment portion DM of a code plate (6) are formed of an integrated plastic molded product, so that the assembly work for the code plate (6) itself is unnecessary. A lens group is formed in a predetermined region of the disk DS. When a fitting portion RE of a shaft member (20) is press fitted into an insertion hole DE, alignment holding portions (J1 to J3) are deformed plastically to thereby achieve the alignment. The attachment portion DM and the shaft member (20) are fixed to each other by engaging a fixing bolt BL with threaded holes DH and RH. A plurality of alignment holding portions (K1 to K3) may be provided at the outer peripheral surface of the attachment portion DM. In this case, the alignment is achieved by press fitting the attachment portion DM into a fitted portion RF and plastically deforming the alignment holding portions (K1 to K3).
    Type: Grant
    Filed: April 13, 1999
    Date of Patent: July 3, 2001
    Assignee: Fanuc Ltd.
    Inventors: Mitsuyuki Taniguchi, Masato Aochi
  • Patent number: 6248993
    Abstract: A steering angle sensor for determining the absolute angle position of a steering wheel of a motor vehicle includes a first sensor unit (4, 12). The first sensor unit (4,12) detects the steering angle position within an angle segment of the entire rotational range of the steering wheel. The first sensor unit (4,12) has a rotor (12) coupled to the rotational movement of the steering wheel. The steering angle sensor further includes a second sensor unit (3,11) for detecting the steering angle position within an angle segment of the entire rotational range of the steering wheel. The second sensor unit (3,11) includes a rotor (11) coupled in a geared manner to the rotational movement of rotor (12) such that the rotors (11,12) have slightly different rotational speeds while the steering wheel is moving. The steering angle position is determined from a measurement value detected by the first sensor unit (3,11) and a measurement value detected by the second sensor unit (4,12).
    Type: Grant
    Filed: June 30, 1999
    Date of Patent: June 19, 2001
    Assignee: Leopold Kostal GmbH & Co. KG
    Inventors: Dirk Bunselmeier, Kersten Rimke, Klaus Hinteresch, Frank Blasing
  • Patent number: 6232885
    Abstract: A meter for measuring electricity usage for a given load includes a housing and two light sources disposed in the housing and configured to output light at a predetermined frequency. Two light receivers are disposed in the housing so that a light path is defined between each light source and its respective light receiver. Each light receiver is configured to receive the light from its light source and to output a signal responsively thereto. A rotatable member is disposed in the housing in the light paths and is rotatable responsively to the electricity usage. The member has a first portion and a second portion. The first portion transmits incident light while the second portion blocks light. The first portion and the second portion are defined on the member so that the member modulates the light as it rotates. A filter circuit in communication with the light receiver is configured to receive the output signal from the light receiver and to detect therefrom modulation of the light by the rotatable member.
    Type: Grant
    Filed: October 15, 1998
    Date of Patent: May 15, 2001
    Assignee: Schlumberger Resource Management Services, Inc.
    Inventors: Ronald E. Ridenour, Scott Swanson
  • Patent number: 6232595
    Abstract: In a position detecting apparatus which detects an absolute position by A/D converting sinusoidal and cosinusoidal signals and performing interpolation, a phase error between the signals which is caused by movement of a detection object during the A/D conversion is corrected, thereby enabling sample hold circuits which have been necessary for maintaining the synchronism of analog signals to be omitted, so as to realize the cost reduction and miniaturization. This is enabled also in an apparatus of high resolution. Position data at requests of the last and preceding times are stored into a RAM 12. On the basis of the position data, a CPU 10 predicts the amount of a phase shift of another signal due to movement during A/D conversion of one signal, corrects the predicted phase shift amount, and then calculates the position data.
    Type: Grant
    Filed: July 10, 2000
    Date of Patent: May 15, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takashi Okamuro, Hirokazu Sakuma, Yoichi Ohmura
  • Patent number: 6232594
    Abstract: A feedback control system has two sinusoidal quadrature position feedback signals generated by photosensitive detectors that sense light reflected from (or transmitted through) position encoding strips that have a reflectance (or transmissivity) that varies sinusoidally along the length of the strip. The system may have one position encoding strip, with two photosensors offset along the length of the strip to provide a ninety degree phase offset. Alternatively, the system may have two strips that are offset in phase by ninety degrees. An error signal is produced directly within the servo loop without requiring computation of ARC-SIN or ARC-COSINE. The error signal is continuous, and position error is not sensitive to photosensor gain.
    Type: Grant
    Filed: June 22, 1999
    Date of Patent: May 15, 2001
    Assignee: Hewlett-Packard Company
    Inventors: Joseph A Eccher, Michael J Steinle
  • Patent number: 6222181
    Abstract: A position measuring apparatus consists of light receiving means in which a plurality of light receiving devices linearly arranged at an equal interval in the one-dimensional case are grouped so that each group includes the same number of light receiving devices and light source means for radiating light on this light receiving means. A single light source system, a plural light source system, a slight difference system, an interference system and an interference slight difference system which are respectively different in the constitution of this light source means are provided. Signals output from grouped corresponding light receiving devices in the respective groups are added and the periodic function is obtained by arranging this added result at an equal interval. The relative position of light receiving means and light source means in actual space can be precisely obtained by calculating the phase of this periodic function.
    Type: Grant
    Filed: February 18, 1999
    Date of Patent: April 24, 2001
    Assignee: Seft Development Laboratory Co., Ltd.
    Inventor: Hiroshi Ichigaya
  • Patent number: 6194708
    Abstract: An encode device, comprises a light source, an encode wheel and a light detector. A hollow dent is formed on the center part of the incident plane of the encode wheel. The inner circumference of the dent is provided with a ring-shaped lens such that the light impinging on the inner circumference of the dent is focused by the ring-shaped lens. The rim of the encode wheel is provided with a plurality of cylindrical lenses which are perpendicular to the ring-shaped lens such that the light leaving the encode wheel can be further focused. Therefore, the working beam projected toward the chip of the light detector has less interference.
    Type: Grant
    Filed: June 9, 1999
    Date of Patent: February 27, 2001
    Inventors: Ching Shun Wang, Cheng-Liang Hsieh, Ming-Hsiang Chu, Yu Shian Liu, Mi-Jung Wang, Nelson Lai, Shu Fang Lu, You-Yan Yang
  • Patent number: 6191415
    Abstract: A position transducer has a moving modulating portion that can move to various positions through rotation, for example. The position transducer provides at least one analog signal that varies periodically with the moving position of the modulating portion, where the movement of the modulating portion has a period. The analog signal is provided to a converter that converts the analog signal into digital information which is applied to a computing arrangement to provide information as to the position of the modulating portion by using at least one transformation including stored information as to deviations of the periodic variation of the analog signal relative to a sinusoidal shape having a constant amplitude for all periods of movement of the modulating portion.
    Type: Grant
    Filed: June 7, 1999
    Date of Patent: February 20, 2001
    Assignee: Stridsberg Innovation AB
    Inventor: Lennart Stridsberg