Single photon avalanche detector devices and circuits for miniaturized 3D imagers

In a new doctoral dissertation in CAS research unit of University of Oulu, a sensor technology has been developed that has enabled the creation of a small-sized low-cost 3-D range camera. The 3-D range camera has many potential applications, such as driverless cars, hand-held devices and games, gesture control and face recognition, smart homes, flying drones and the control of heavy machinery.

The sensor is implemented with a commercially available semiconductor (CMOS) technology and works based on the ‘time of flight’ distance measurement technique. It sends hundreds of thousands of invisible very short laser pulses per second to illuminate the objects of a scene. The laser pulses travel the distance to the objects and back to the camera at the speed of light. Each of the sensor’s 8-kilo single-photon detector pixels detects the returning photons from a specific part of the scene. By measuring the photon travel times, the distance to different objects can be calculated. The realized 3-D camera prototype has a size similar to standard compact cameras and is one of the first solid-state (no mechanically moving parts) complete 3-D camera developments. It can measure object distances up to 10 meters with a frame rate up to 20 frames per second.