Demodulation Pixel Based on Static Drift Fields

Abstract

A novel pixel architecture for two-dimensional pixel parallel demodulation of modulated light waves is introduced, enabling real-time three-dimensional (3-D) imaging. Applications for such methods can be found in the field of surveillance, robotics, automotive, and industry security applications. The pixel architecture is based on large areas of static drift fields and relatively small demodulation regions. The large area of static drift field forms the basic photodetection region. The constant drift field enables the very fast transport of photo-generated charges to the sampling region where demodulation of the light signal is performed. The main advantages compared to recently used demodulation pixels are lower power consumption and higher optical fill factor or sensitivity. The first implementation is a pixel of 40times40 mum <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> size with 25% optical fill factor. Measurements prove the concept of transporting photo-generated charges within less than 1 ns to the demodulation node. The applicability of the pixel in 3-D imaging applications is highlighted by distance measurements achieving millimeter distance resolution