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Proceedings Paper

Time-of-flight based pixel architecture with integrated double-cathode photodetector
Author(s): Klaus Oberhauser; Gerald Zach; Alexander Nemecek; Horst Zimmermann
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Paper Abstract

For various industrial applications contact-less optical 3D distance measurement systems with active illumination are suitable. A new approach for a pixel of such a 3D-camera chip for applications in displacement and 3D-shape measurement is presented here. The distance information is gained by measuring the Time-of-Flight (TOF) of photons transmitted by a modulated light source to a diffuse reflecting object and back to the receiver IC. The receiver is implemented as an opto-electronic integrated circuit (OEIC). It consists of a double-cathode photodetector performing an opto-electronic correlation, a decoupling network and an output low-pass filter on a single silicon chip. The correlation of the received optical signal and the electronic modulation signal enables the determination of the phase-shift between them. The phase-shift is directly proportional to the distance of the object. The measurement time for a single distance measurement is 20 ms for a range up to 6.2 m. The standard deviation up to 3.4 m is better than 1cm for a transmitted optical power of 1.2 mW at a wavelength of 650 nm. The OEIC was fabricated in a slightly modified 0.6 &mgr;m BiCMOS technology with a PIN-photodetector. The photosensitive area of the integrated PIN-photodetector is 120x115 &mgr;m2. A fill factor of ~67% is reached.

Paper Details

Date Published: 18 June 2007
PDF: 9 pages
Proc. SPIE 6616, Optical Measurement Systems for Industrial Inspection V, 66160C (18 June 2007); doi: 10.1117/12.725655
Show Author Affiliations
Klaus Oberhauser, Vienna Univ. of Technology (Austria)
Gerald Zach, Vienna Univ. of Technology (Austria)
Alexander Nemecek, Vienna Univ. of Technology (Austria)
Horst Zimmermann, Vienna Univ. of Technology (Austria)

Published in SPIE Proceedings Vol. 6616:
Optical Measurement Systems for Industrial Inspection V
Wolfgang Osten; Christophe Gorecki; Erik L. Novak, Editor(s)

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