With A Single Photodetector Having Multiple Elements Patents (Class 356/3.06)
  • Patent number: 11372107
    Abstract: Triangulation photoelectric proximity sensor (1) having a first light emitter (2) for emitting transmitted light into a detection zone (3), a transmitting optical system (4), in particular a lens, being arranged upstream of the light emitter (2), a first light receiver (6) having an array of receiving elements (5) for receiving light from the detection zone (3), which is remitted by an object (7) to be detected, the receiving elements (5) generating respective received signals, a receiving optical system (8) arranged in the beam path between detection zone (3) and first light receiver (6) for generating a light spot from the remitted light on the first light receiver (6), wherein the position of the light spot in the triangulation direction on the first light receiver (6) results in dependence on the distance of the object (7), and a control and evaluation unit (9) for generating a detection signal from the received signals on the basis of the position of the light spot on the first light receiver (6), wherei
    Type: Grant
    Filed: January 25, 2019
    Date of Patent: June 28, 2022
    Assignee: SICK AG
    Inventor: Kai Waslowski
  • Patent number: 11280889
    Abstract: A distance measuring sensor assembly and an electronic device having the same, the sensor assembly including: a housing; a first lens provided at an upper part of the housing; a sensor module provided inside the housing, and having a light emitting part aligned with the first lens and emitting light toward an object, and a light receiving part disposed to be adjacent to the light emitting part. A reception part is provided at the upper part of the housing and spaced apart from the first lens. The light reflected from the object enters through the reception part. A second lens is provided at a lower part of the reception part and refracts the light entering from the reception part, and an optical waveguide part coupled to the second lens is used to guide the light having transmitted from the second lens to the light receiving part.
    Type: Grant
    Filed: April 6, 2017
    Date of Patent: March 22, 2022
    Assignee: MOSTOP CO., LTD.
    Inventors: Seung Soo Lee, Won Kyu Lim, Kyung Eui Hong, Yi Hyun Nam, Keun Won Lee
  • Patent number: 11263768
    Abstract: A 3D information calculation apparatus includes processing circuitry that may receive first and second images of different first and second wavelength bands, respectively, at a same time and angle of view based on a subject being imaged while structured light of the first wavelength band is projected on to subject, receive third and fourth images of the first and second wavelength bands, respectively, at a same time and angle of view based on the subject being imaged while the structured light is not projected on the subject, calculate a first difference image of the first wavelength band based on subtracting the first and third images, calculate a second difference image of the second wavelength band based on subtracting the second and fourth images, calculate an extraction image based on subtracting the first and second difference images, and calculate a distance to the subject based on the extraction image.
    Type: Grant
    Filed: December 19, 2019
    Date of Patent: March 1, 2022
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Takashi Okazaki, Mineki Taoka
  • Patent number: 11218675
    Abstract: Provided is a computation method for obtaining information suitable for positional deviation correction and lens blur correction for a case where a part of or an entire projection image projected by each of a plurality of projectors is displayed in a superimposed manner. For this purpose, a light intensity distribution indicating a degree of lens blur of a base projector and peak coordinates of the light intensity distribution are calculated using a captured image obtained by capturing a test pattern projected by the base projector in an arrangement state in which a plurality of projectors is arranged such that a part of or an entire projection image projected by each of the plurality of projectors is displayed in a superimposed manner.
    Type: Grant
    Filed: January 16, 2019
    Date of Patent: January 4, 2022
    Assignee: SONY CORPORATION
    Inventors: Haruka Asai, Noriaki Takahashi
  • Patent number: 11006026
    Abstract: Provided is an image capturing apparatus that not only prevents excitation light from leaking into RGB but also corrects a difference of focal points between visible light and IR and corrects levels of visible light and IR without having a complicated structure. An image capturing apparatus 10 includes a light irradiation unit 12 that irradiates an object including a fluorescent material with excitation light and illuminating light, a four-color separation unit 16 that separates light incident upon a lens 14 into R, G, B, and IR, an image sensor 18 that performs photoelectric conversion on each separated light, a picture signal output unit 20 that generates a picture signal from an electrical signal obtained by the photoelectric conversion, a picture display 22 that displays a picture based on the picture signal, a bandpass filter 24 that does not transmit light near a wavelength band of the excitation light, and a correction filter 26.
    Type: Grant
    Filed: July 11, 2018
    Date of Patent: May 11, 2021
    Assignee: IKEGAMI TSUSHINKI CO., LTD.
    Inventor: Takaaki Saito
  • Patent number: 10965376
    Abstract: A cover for an electronic circuit package, including: a body having an opening extending therethrough; a first element located in the opening and having a surface continuing planar or rounded shapes of a surface of the cover; and a second element of connection of the first element to the body.
    Type: Grant
    Filed: December 13, 2018
    Date of Patent: March 30, 2021
    Assignee: STMICROELECTRONICS (GRENOBLE 2) SAS
    Inventors: Jean-Michel Riviere, Romain Coffy, Karine Saxod
  • Patent number: 10564265
    Abstract: A measurement device and measurement method are provided which are capable of measuring the inclination of a measurement target object surface both with a simple configuration and at high speed. The measurement device includes: a rangefinding light emitting section; a rangefinding unit configured to receive reflected rangefinding light; an optical axis deflection section provided on an optical path common to rangefinding light and reflected rangefinding light, and configured to deflect optical axes thereof; a motor configured to cause the optical axis deflection section to rotate; an emission direction detection unit configured to detect a deflection angle and deflection direction resulting from the optical axis deflection section; and a computation controller that measures the inclination of a measurement target object surface with respect to the emission optical axis on the basis of acquired coordinate data on the measurement target object surface.
    Type: Grant
    Filed: September 25, 2017
    Date of Patent: February 18, 2020
    Assignee: Topcon Corporation
    Inventors: Takahiro Inoue, Satoshi Yanobe, Hideyuki Matsumoto, Fumio Ohtomo
  • Patent number: 10520589
    Abstract: A multimode pixel of a pixel array is provided. The multimode pixel includes a photodetector, an image sensing circuit having a first plurality of transistors, and a laser range finding (LRF) circuit having a second plurality of transistors. At least one transistor of the second plurality of transistors, but not all of the second plurality of transistors, is included in the first plurality of transistors. The LRF circuit being configured to perform LRF operations and the image sensing circuit is configured to perform passive imaging operations. The image sensing circuit and the LRF circuit are configured to perform concurrently.
    Type: Grant
    Filed: October 16, 2017
    Date of Patent: December 31, 2019
    Assignee: Sensors Unlimited, Inc.
    Inventors: John Liobe, Joshua Lund
  • Patent number: 9677914
    Abstract: An optoelectronic sensor for recognizing object edges of objects comprises at least three light transmitters which are arranged such that at least two different spacings result between two respective light transmitters. For recognizing an object edge, an evaluation unit is configured to carry out a common evaluation of an image taken by a light receiver of a light spot generated by the transmitted light beams of a first light transmitter and of an image taken by a light receiver of a light spot generated by the transmitted light beams of another light transmitter. The pair of light transmitters to be used for the common evaluation can be selected in dependence on a selection criterion from at least two differently spaced apart pairs of light transmitters.
    Type: Grant
    Filed: May 6, 2014
    Date of Patent: June 13, 2017
    Assignee: SICK AG
    Inventors: Gerhard Merettig, Roland Bergbach, Matthias Schonstein, Ingolf Horsch, Matthias Gotz, Alexander Bohli
  • Patent number: 9448106
    Abstract: To provide an optical sensor that can ensure accuracy of positions of a light projecting unit and a light receiving unit in a case. The optical sensor includes a case, an integrated light projecting module that includes a light emitting unit and a light projecting lens, a light receiving unit configured to receive reflected light of light projected from the light projecting module, and a light receiving lens unit configured to form an image of the reflected light on the light receiving unit. The light projecting module, the light receiving unit, and the light receiving lens unit are each independently and directly fixed to the case.
    Type: Grant
    Filed: September 18, 2013
    Date of Patent: September 20, 2016
    Assignee: OMRON CORPORATION
    Inventors: Kenji Murata, Kenta Yamakawa, Kosuke Uemura
  • Patent number: 9410844
    Abstract: To provide an optical sensor that can ensure accuracy of positions of a light projecting unit and a light receiving unit in a case. The optical sensor includes a case, an integrated light projecting module that includes a light emitting unit and a light projecting lens, a light receiving unit configured to receive reflected light of light projected from the light projecting module, and a light receiving lens unit configured to form an image of the reflected light on the light receiving unit. The light projecting module, the light receiving unit, and the light receiving lens unit are each independently and directly fixed to the case.
    Type: Grant
    Filed: September 18, 2013
    Date of Patent: August 9, 2016
    Assignee: OMRON CORPORATION
    Inventors: Kenji Murata, Kenta Yamakawa, Kosuke Uemura
  • Patent number: 9341517
    Abstract: Systems that enable observing celestial bodies during daylight or in under cloudy conditions.
    Type: Grant
    Filed: March 17, 2014
    Date of Patent: May 17, 2016
    Assignee: Wavefront Research, Inc.
    Inventor: Thomas W. Stone
  • Patent number: 9205850
    Abstract: A displacement detecting apparatus is provided with a self-position detector for detecting a position and an orientation of the apparatus relative to a preset reference position and a preset reference orientation. Displacement of a rail at an upper surface reference point and a side surface reference point relative to a preset reference position is calculated from imaged image data of the surfaces of the rail using an optical cutting method, and the calculated displacement of the rail is corrected using data obtained from the self-position detector, thereby compensating for errors caused by differences in position and orientation of the apparatus associated with a vehicle running motion. By doing so, the displacement detecting apparatus is superior in maintenance and unlikely to cause measurement errors.
    Type: Grant
    Filed: December 12, 2012
    Date of Patent: December 8, 2015
    Assignee: KAWASAKI JUKOGYO KABUSHIKI KAISHA
    Inventors: Tadao Shimada, Masayuki Mitsue, Masayuki Enomoto
  • Patent number: 8787653
    Abstract: What is disclosed is a system and method for determining an orientation direction of a color edge at a given pixel location in a binary color image. The orientation direction of the color edge is determined from eight pixel counts with each pixel count being a total number of pixels in each of eight regions of a window centered about a candidate pixel which resides along the color edge. The eight regions are associated with 8 compass points. The orientation of the edge is determined by a 1st, 2nd and 3rd tier control bits which are based upon the pixel counts of each region. The 1st, 2nd and 3rd tier control bits collectively form a 3-bit word. The 3-bit word defines the orientation direction. The teachings hereof provide an efficient way of performing binary edge orientation detection by making uses of intermediate results to simultaneously encode the edge orientation.
    Type: Grant
    Filed: March 21, 2012
    Date of Patent: July 22, 2014
    Assignee: Xerox Corporation
    Inventors: Xing Li, Meng Yao, Barbara L. Farrell
  • Patent number: 8735824
    Abstract: An infrared sensor module includes a first infrared sensor that includes a first light emitting unit configured to emit infrared light to an object and a first light receiving unit configured to detect an amount of infrared light reflected from the object, a second infrared sensor that includes a second light emitting unit configured to emit infrared light to the object and a second light receiving unit configured to detect an amount of the infrared light reflected from the object, and a controller to measure reflectivity of the object using a peak output voltage of the first light receiving unit, and to measure a distance to the object using not only the measured object reflectivity but also an output voltage of the second light receiving unit. As a result, the distance from the infrared sensor to the object can be correctly measured irrespective of the reflectivity of the object.
    Type: Grant
    Filed: November 1, 2011
    Date of Patent: May 27, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jun Pyo Hong, Jea Yun So, Sang Sik Yoon
  • Patent number: 8576402
    Abstract: A system for optical navigation includes a light source and an imaging system. The light source illuminates a navigation surface. The navigation surface reflects light from the light source. The imaging system is located approximately within a path of the reflected light. The imaging system includes a lens, a mask, and an image sensor. The lens receives reflected light from the navigation surface. The lens focuses a specular portion of the reflected light to a focus region. The mask is located at approximately the focus region. The mask filters out substantially all of the specular portion of the reflected light and passes at least some of a scatter portion of the reflected light outside of the focus region. The image sensor generates a navigation signal based on the scattered portion of the light that passes outside the focus region and is incident on the image sensor.
    Type: Grant
    Filed: July 22, 2010
    Date of Patent: November 5, 2013
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventor: Omid Momtahan
  • Patent number: 8427632
    Abstract: A method of image-based positioning is provided. The method comprises: (A) providing an image-capturing device integrated with a focused-radiation source and a processor; the image-capturing device further comprises an image sensor; (B) capturing an image of an object located in a field of view (FOV) of the image-capturing device by using the image sensor; (C) directing a focused ray of radiation generated by the focused-radiation source to the object located in the (FOV) of the image-capturing device; (D) detecting at least one return signal generated by reflection of the focused ray of radiation from the object located in FOV of the image-capturing device by using the image sensor; (E) characterizing the object located in a field of view (FOV) of the image-capturing device by using each return signal; and (F) processing each return signal in order to determine a distance from the object located in the FOV to the image-capturing device.
    Type: Grant
    Filed: December 23, 2009
    Date of Patent: April 23, 2013
    Assignee: Trimble Navigation Ltd.
    Inventors: Phillip T. Nash, Gregory C. Best
  • Patent number: 8284383
    Abstract: An object recognition apparatus performs a sweep of a scanned region by transmitting scanning wave beams at respective scan angles and successive timings, derives a received-wave signal strength value and reflection location corresponding to each scan wave beam during the sweep, and assigns a set of mutually adjacent reflection locations as a segment. A corresponding range value of the segment is calculated, expressing an estimated distance of a detected object. A threshold value is derived in accordance with the segment range, a region of the segment in which the signal strength values exceed the threshold value is extracted, and the width of the extracted region is designated as the width of the detected object.
    Type: Grant
    Filed: November 30, 2010
    Date of Patent: October 9, 2012
    Assignee: Denso Corporation
    Inventors: Taro Beppu, Kiyokazu Takagi, Takashi Ogawa, Hiroshi Hazumi
  • Patent number: 8054304
    Abstract: A photo detector is disclosed. The photo detector includes a substrate, a first patterned semiconductor layer with a first state, a dielectric layer, a patterned conductive layer, an inter-layer dielectric, a second patterned semiconductor layer with a second state, two first electrodes disposed on the inter-layer dielectric and two second electrodes disposed on portions of the second semiconductor layer. The first patterned semiconductor layer having a first doping region and a second doping region is disposed on a transistor region of the substrate. The dielectric layer is disposed to cover the substrate and the first semiconductor layer, the patterned conductive layer is disposed on the dielectric layer, and the inter-layer dielectric having at least two openings adapted to expose the first doping region and the second doping region is disposed to cover the dielectric layer.
    Type: Grant
    Filed: November 21, 2007
    Date of Patent: November 8, 2011
    Assignee: AU Optronics Corp.
    Inventors: Yu-Min Lin, Hsin-Li Chen, Feng-Yuan Gan
  • Patent number: 7760332
    Abstract: An optical range-finding sensor includes a light-emitting element that emits irradiation light, a light-emitting side lens that collects the irradiation light and irradiates the light to a range-finding object, a light-receiving side lens that collects reflected light of the irradiation light reflected by the range-finding object, a position detecting light-receiving element that receives the collected reflected light and detects a position of the range-finding object, and a control processing integrated circuit that controls light emission of the light-emitting element and processes a detection current of the position detecting light-receiving element. The light-emitting element is configured of a vertical cavity surface emitting laser.
    Type: Grant
    Filed: September 15, 2008
    Date of Patent: July 20, 2010
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Akifumi Yamaguchi
  • Patent number: 7327440
    Abstract: A distance measuring device is disclosed which can measure the distance to an object located within a known range. The device uses beam splitters and lenses to focus and direct energy reflected from an object onto at least two bi-sensors. The bi-sensors each have an inner sensing area and an outer sensing area. When the device has been properly calibrated, the reflected energy will be focused such that almost all of it will fall into the inner sensing area of one be-sensor when the object is at the minimum distance in the known range and when the object it at the maximum distance almost all of the energy will fall onto the inner sensing area of the other sensor. The distance to an object is calculated by comparing the ratio of the energy on the inner sensing areas of the two sensors with a table of known ratio verses distance values.
    Type: Grant
    Filed: August 12, 2005
    Date of Patent: February 5, 2008
    Inventor: James N Horn
  • Patent number: 7034950
    Abstract: The laser grid (1) permits a single-sided installation in order to record a person or object in the monitoring area. The grid operates using punctiform sensor units (3), each including at least one laser diode and two photosensitive pixels. The sensor units are arranged in a line in a housing (2).
    Type: Grant
    Filed: May 10, 2004
    Date of Patent: April 25, 2006
    Assignee: Siemens Aktiengesellschaft
    Inventors: Holger Waschke, Peter Mengel
  • Patent number: 7022966
    Abstract: A position and color detection sensor (for detecting a position of a light spot in a light distribution that can include stray light components, e.g. from other lasers, ambient lighting etc.) includes two discrete response position sensitive detectors (DRPSDs). The first DRPSD is used to calculate a raw estimate of the spot position and the second DRPSD is used to calculate the actual spot position based on information from the first DRPSD. Color is supported by further dividing each pixel of the first DRPSD into elementary photocells, each one covered with an appropriate optical filter. The use of two DRPSDs differing in pixel geometries makes them suitable for integration on the same chip using the same process. This reduces production and alignment costs. Further, analogue microelectronic processes can be used for color filter deposition and simple optics can be used for beam splitting and shaping.
    Type: Grant
    Filed: July 31, 2002
    Date of Patent: April 4, 2006
    Assignees: National Research Council of Canada, Istituto Trentino Di Cultura
    Inventors: Lorenzo Gonzo, Andrea Simoni, Massimo Gottardi, J. Angelo Beraldin
  • Patent number: 6806968
    Abstract: The invention is directed to an apparatus for measuring a workpiece and includes a coordinate measuring apparatus or a machine tool. The invention further relates to a method for measuring the workpiece using such an apparatus. The apparatus includes a control and evaluation unit (26) and at least one measuring sensor (6) which functions independently of the control and evaluation unit and which can be displaced by a mechanism (27) of the coordinate measuring device in the three coordinate directions (x, y, z) in relation to the workpiece. The apparatus includes timers which are provided both in the measuring sensor (6) and in the control and evaluation unit (28) in order to synchronize the measuring sensor (6) and the control and evaluation unit (28). The timers function independently from each other and are adjusted to a common starting time.
    Type: Grant
    Filed: October 28, 2002
    Date of Patent: October 19, 2004
    Assignee: Carl-Zeiss Stiftung
    Inventor: Otto Ruck
  • Publication number: 20040135989
    Abstract: A cloud imaging system monitors a condition of a portion of the sky. A lens defines a focal plane upon which the portion of the sky is directly mapped. An infrared sensor is disposed in the focal plane of the lens. The infrared sensor outputs data representative of the monitored portion of the sky. The data is interpreted to discover the condition of the monitored portion of the sky.
    Type: Application
    Filed: January 9, 2003
    Publication date: July 15, 2004
    Inventor: Dimitri I. Klebe
  • Patent number: 6522394
    Abstract: A rangefinder device and a camera are provided, which, in measuring a distance by the active method, are capable of properly measuring the distance even if the object to be measured is located at a short distance, while in measuring a distance by the passive method, are capable of measuring the distance without causing the conflict between far and near objects. A projecting section projects spot-shaped light on a range-finding object. A light receiving section comprises a plurality of photoelectric converting elements. A first calculating section calculates distance measurement information based on an output from the light receiving section receiving reflected light from the range-finding object, by driving the projecting section to project the light, and a second calculating section calculates distance measurement information based on an output from the light receiving section receiving extraneous light reflected from the range-finding object, without driving the projecting section.
    Type: Grant
    Filed: August 22, 2001
    Date of Patent: February 18, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takashi Ichimiya
  • Patent number: 6522393
    Abstract: A distance measuring device includes a light emitting system that emits light toward an object that is subject to a distance measurement. A light receiving system is provided to receive optical images which are formed by an optical system. The light receiving system outputs data corresponding to the received images. The light receiving system is capable of receiving the object images when the light emitting system emits the light, and when the light emitting system does not emit the light. Further, the distance measuring device includes a control system that receives the data output by the light receiving system twice at the greatest, and performs distance measuring operations, which include a passive distance measurement and an active distance measurement, based on the data output by the light receiving system.
    Type: Grant
    Filed: May 1, 2001
    Date of Patent: February 18, 2003
    Assignee: Pentax Corporation
    Inventor: Fuminobu Higashino
  • Patent number: 6492652
    Abstract: The opto-electronic sensor (1) for the measurement of the distance (d) to an object (9), resp., for the identification of an object (9) within a monitoring zone (90) is based on triangulation measurement. A light source (21) emits light onto the object (9) or into the monitoring zone (90). The light (35) scattered by the object (9) impinges on a receiving element (31) at an angle (&agr;), which is dependent on distance (d) to the object (9). The latter has tappings (34.1-34.5) distributed over its length, in order to by means of a corresponding selection of these bring the measuring range of the sensor (1) to the value required by a control circuit (4) and as a result of this to increase the measuring resolution correspondingly. In variable amplifiers (6.1, 6.2), two or more detector signals (I1′, I2′) are multiplied with a variable factor respectively determined by the control circuit (4) and subsequently added, resp., subtracted in an adding—or subtracting stage (7).
    Type: Grant
    Filed: December 20, 2000
    Date of Patent: December 10, 2002
    Assignee: Hera Rotterdam B.V.
    Inventor: Daniel Müller
  • Patent number: 6433857
    Abstract: Disclosed herewith is an optical triangulation displacement sensor using a diffraction grating. The optical triangulation displacement sensor includes a light source element, a condenser, a light-receiving element, an image formation lens, a transmission grating and a light-receiving element. The light source element generates light of certain intensity. The condenser receives the light from the light source element and transmits the light to the surface of measurement. The image formation lens receives the light reflected by the surface of measurement. The transmission grating converts the reflected light having passed through the image formation lens into a plurality of diffracted light rays. In the light-receiving element, an image is formed by the diffracted light rays incident from the transmission grating.
    Type: Grant
    Filed: April 19, 2001
    Date of Patent: August 13, 2002
    Assignee: Korea Advanced Institute of Science and Technology
    Inventors: Soo Hyun Kim, Kyung Chan Kim, Se Baek Oh
  • Patent number: 6359680
    Abstract: A three-dimensional object measurement process and device are disclosed by means of optical image capture, projection of patterns and triangulation calculations. The pattern projection unit and the image capture unit are separately designed and can be independently positioned and guided during the measurement process. This is particularly advantageous for diagnosis, therapy and documentation in the field of invasive medicine.
    Type: Grant
    Filed: March 11, 1999
    Date of Patent: March 19, 2002
    Assignee: OraMetrix, Inc.
    Inventor: Rudger Rubbert
  • Patent number: 6353478
    Abstract: A digital range sensor comprises a light source, an optical element to focus the light from the source down to a small spot on a target, a second optical element that is mounted obliquely from the source axis, and a prism mounted on a multi-element detector, which in turn is mounted at the focus of the light returning from the target. The purpose of the prism on the detector is to direct the light onto the active surface of the detector at an angle closer to normal incidence than would otherwise be possible. The detector produces digital data which is transferred to a control module for processing and to produce a numerical range measurement.
    Type: Grant
    Filed: September 3, 1999
    Date of Patent: March 5, 2002
    Assignee: CyberOptics Corporation
    Inventors: Eric P. Rudd, William P. Kennedy, Troy R. Pesola, David D. Madsen
  • Patent number: 6330055
    Abstract: A distance measuring apparatus for measuring the distance to an object has a line of charge coupled device (CCD) elements which serve as two sensors for passive sensing and one sensor, in combination with a light emitting element, for active sensing. An infrared light cut-off filter is provided on the light receiving surface of all the elements while a visible light cut-off filter is provided on the light receiving surface of the elements corresponding to the active sensor. The light emitting element is provided with a pattern mask so that the object is irradiated with a pattern of light intensity. The active sensor detects the pattern and from this the position of the spectral center of the image can be determined to enable a distance value to be ascertained.
    Type: Grant
    Filed: September 27, 1999
    Date of Patent: December 11, 2001
    Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
    Inventor: Fuminobu Higashino
  • Patent number: 6317200
    Abstract: A measurement apparatus (10, 110) and methods to perform positional types of measurement with normalization respective to either or both of light beam (16, 116) intensity and measurement target (12, 112) reflectivity. A light source, such as a laser diode (14, 114), produces a light beam (16, 116) which is directed at the measurement target (12, 112). One or more beamsplitters (28, 120, 124) in the path of the light beam (16, 116) direct sample portions into one or more photodetectors (32, 36, 122, 128) to obtain either or both of illumination and reflectivity sample values. A portion of the light beam (16, 116) which is reflected by the measurement target (12, 112) is passed through and restricted by an aperture (26, 132) and then detected by a position sensitive detector (38, 134) to obtain a position value. The position value may then be normalized based on either or both of the illumination and reflectivity sample values.
    Type: Grant
    Filed: April 13, 2000
    Date of Patent: November 13, 2001
    Assignee: Excel Precision Corp.
    Inventors: Mao Wang, John C. Tsai