I don't think it's doable with today's technology, that's why laser-based retina projection is what everybody's working on right now. Achieving the same effect

I don't think it's doable with today's technology, that's why laser-based retina projection is what everybody's working on right now. Achieving the same effect with a thin and semitransparent lens would require a lot of engineering to achieve tightly controllable photon angles and I imagine power/data transmission to the lens would also be an issue. Also, personally I would rather put on a pair of glasses than stick a piece of plastic directly into my eye.