Abstract:

In this thesis, a 3D CMOS imager based on time-of-flight (TOF) has been developed and successfully tested. It uses an active pulsed class 1 laser operating at 910nm to illuminate a 3D scene. The scene depth is determined by measurement of the travel time of reflected pulses by employing a fast on-chip synchronous shutter. A so-called “Multiple Double Short Time Integration” (MDSI) enables suppression of the background illumination and correction for reflectivity variations in the scene objects. The sensor chip contains two pixel lines with each pixel containing twin photodiodes, thus the chip contains 4´64 sensors. The chip allows tow operating modes; the first is the binning mode, where the twin pixels are short-circuited (tow lines on the die) and the average signal is measured. The second mode is the high-resolution mode. In this mode the pixels operate separately (four lines on the die). The chip has been realized in 0.5mm n-well standard CMOS process. The pixel pitch is 130mm. To get a good fill factor, the readout circuitry is located at the sides of the chip.