ISSCC 2004 / SESSION 6 / IMAGING / 6 . 7 6 . 7 . A CMOS Single Photon Avalanche Diode Array for 3 D Imaging

Time-of-flight (TOF) measurements using pulsed light beams for 3D imaging or profiling require either a costly mechanical device to scan the scene [1] or a short and highly energetic optical pulse to flood the scene with photons [2]. An alternative to these methods is the use of detector arrays based on single photon avalanche diodes (SPADs) operating in Geiger mode [3]. These devices accurately detect the arrival of a single photon and are therefore effective in computing TOF of extremely small bursts of optical power even when the source is uncollimated and diffused over a wide cone of light. Thus, SPAD arrays are indicated for 3D imaging of volumes of several cubic meters at sub-millimetric axial resolutions. This approach becomes attractive with the recent integration of SPAD arrays in standard CMOS technology [3].