EETimes: Rambus presented a poster "Lensless Smart Sensors: Optical and Thermal Sensing for the Internet of Things" at VLSI Symposia 2016. The sensor utilizes a phase anti-symmetric diffraction grating on top of a conventional pixel array and computational algorithms that extract the relevant information from the image.
"In some applications such as range-finding or eye-tracking, it may not even be necessary to reconstruct a full image. Instead, extracting distance measurements may suffice and the particular phase anti-symmetric diffraction structure makes it very simple, explains the poster.
The ultra-low power 2x2mm2 image sensor with a 128x128 pixel array and integrated image change detection circuitry on the same die was enough to measure distances up to 50cm with an error of less than 8%, they reported."
"We do see this as a better, more accurate replacement for head-mounted eye tracking systems like those found in Virtual and Augmented Reality systems. We don’t target the LSS product for remote eye tracking, such as PC display or television based implementations", said Paul Karazuba, Director of Product Marketing for Imaging at Rambus.