Passive Proximity Detection Based on a Miniaturized Pyramidal Optical Sensor

In this paper, we present the design principle and experimental results from a fabricated prototype of an optical proximity sensor. The sensor base is a pyramid with light sensors attached to its sides and the top. The sensor estimates the direction and distance to the light source using ratios of light intensity received on the sides. We demonstrate that it is further possible to decompose a single pyramid into two virtual, off-center pyramids. Using the independently measured angles to the light sources from these two pyramids, it is possible to estimate the distance to the light source. Advantages of the presented approach to existing proximity sensors include: Passive operation, Low power consumption, Simple fabrication and Wide response angle. The device structure can be realized using standard microfabrication techniques, providing a straightforward path for mass-manufacturing and arraying such devices.