PIN-photodiode based pixel architecture for high-speed optical distance measurement systems

Contact-less optical distance measurement systems are necessary to obtain 3D-information of an entire scene. To be able to determine depth information of the scene by a sensor without moving parts like e.g. scanner, it is necessary to measure the distance from the camera to an object in every single pixel. A new pixel for such a 3D-camera is presented. The operating principle is based on the time-of-flight (TOF) of laser light from 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 fast, efficient PIN-photodiode having a 3dB bandwidth of about 1.35 GHz, a single-stage transimpedance amplifier and an electronic mixer on a single silicon chip. By correlating the received optical signal and the original electronic modulation signal, the phase-shift between sent and received signal can be determined. By performing correlation with a delayed modulation signal it is possible to eliminate the influence of object reflectivity and background illumination. The measurement time for a single distance measurement is 500μs for a range up to 3.7m. The standard deviation at 2.5m is better than 3cm for a transmitted optical power of 1.44mW at a wavelength of 650nm. The OEIC was fabricated in a slightly modified BiCMOS 0.6μm process. The diameter of the photosensitive area of the integrated PIN-photodiode is 100μm. The effective pixel size is about 220x400μm2. Therefore a fill factor of ~9% is reached.

[1]  K. Asada,et al.  A 120/spl times/110 position sensor with the capability of sensitive and selective light detection in wide dynamic range for robust active range finding , 2004, IEEE Journal of Solid-State Circuits.

[2]  A. Simoni,et al.  A CMOS smart pixel for active 3D vision applications , 2002, Proceedings of IEEE Sensors.

[3]  E. Charbon,et al.  Toward a 3-D camera based on single photon avalanche diodes , 2004, IEEE Journal of Selected Topics in Quantum Electronics.

[5]  Horst Zimmermann,et al.  Simple feedback network for bandwidth enhancement of , 2003 .

[6]  Horst Zimmermann,et al.  Amplifier with Capacitive-Coupled Voltage Dividers , 2004 .

[7]  Manfred Berroth,et al.  Monolithically integrated CMOS current-mode transimpedance , 2003 .

[8]  J. Kostamovaara,et al.  Integrated time-of-flight laser radar , 1996, Quality Measurement: The Indispensable Bridge between Theory and Reality (No Measurements? No Science! Joint Conference - 1996: IEEE Instrumentation and Measurement Technology Conference and IMEKO Tec.

[9]  T. Oggier,et al.  4 . 1 3 D-Imaging in Real-Time with Miniaturized Optical Range Camera , 2005 .

[10]  Robert Lange,et al.  3D time-of-flight distance measurement with custom solid-state image sensors in CMOS/CCD-technology , 2006 .

[11]  W. Brockherde,et al.  A 4/spl times/64 pixel CMOS image sensor for 3-D measurement applications , 2004, IEEE Journal of Solid-State Circuits.