A Micromachined Vector Light Sensor

We report the design, fabrication, and performance characteristics of a novel microfabricated light sensor designed to determine the intensity and direction of an incident light source. The device structure comprises several light sensors that are integrated onto a pyramid base. The direction to the light source is estimated using the ratios of the signals from the lights sensors that are facing different directions. We demonstrate that this “vector light sensor”, is capable of measuring both the intensity and the direction of light from a source. The three-dimensional structure of the sensor is created based on well-known silicon microfabrication techniques and uses photodiodes for the detection of visible light. The signals from the photodiodes were read and processed based on a simple algorithm to experimentally verify the device performance. In addition to the direction, the distance to a light source may be estimated by simple triangulation of data from two vector light sensors. The small size and low power consumption of the individual sensors make them suitable for applications where passive distance and direction estimation is required. Furthermore, it is envisioned that arrayed sensors can directly provide light-field information in a plane.