/diy/ - Do It Yourself

I want to make an augmented reality device.
I plan to use a raspberry pi + camera with opencv to do face/object detection so I can become JC Denton

for the optics themselves I have been trying to think of a way to project an image into view while still being mostly in focus
What I came up with was a piece of reflective but see through plastic at a 45 degree angle to your eye and an lcd reflects onto it. in order to make it in forcus you would need a lens right in front of your eye like how VR headsets work but this would make everything else in the real world blurry. but since I essentially have a 45 degree mirror, can I put the lens before the mirror (so it is not directly in front of the eye) to make it look in focus?

pic related trying to use a light simulator but too brainlet
would it work even? how would I calculate the focal lengths?