Pinhead mirror
A pinhead mirror can be used to create a camera similar to a pinhole camera. Instead of passing through a tiny aperature, the light to form the image is reflected by a small disc-shaped mirror. One advantage is that a pinhead mirror can be swiveled to scan a scene or project a scene to different locations.
Pinhead mirror technology was protected under US patent 4,948,211 - "Method and Apparatus for Optical Imaging Using a Small, Flat Reflecting Surface" until the patent expired in 2009.
