Babak Parviz had a team working on this at UW back in 2010 (https://spectrum.ieee.org/augmented-reality-in-a-contact-lens https://spectrum.ieee.org/augmented-re

Babak Parviz had a team working on this at UW back in 2010 (https://spectrum.ieee.org/augmented-reality-in-a-contact-lens https://spectrum.ieee.org/augmented-reality-in-a-contact-len...). They wanted to use either an LED array with microlenses, or (as you allude) a kind of laser DLP. Both approaches are feasible for projecting a virtual image onto the retina, but integrating them in a working product is very difficult, as illustrated by Parviz's trajectory at Google.