How does Microsoft project an image so close to the eye yet understandable by the brain?
How is the display transparent?
This link has good information but is speculative. https://www.reddit.com/r/HoloLens/comments/2v0nac/hololens_display_tech_and_what_to_expect_from_it/
What materials are used?
For a list of patents see this: http://vrwiki.wikispaces.com/Microsoft+HoloLens