Engineering:Pinhead mirror

From HandWiki
Principle of a pinhead camera. Light rays from the object reflect off a small mirror and are projected as an image.

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 (with a diameter the same as that of a pinhole; about 0.15 mm - 0.4 mm). One advantage is that a pinhead mirror can be swiveled to scan a scene or project a scene to different locations.[1][2]

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.

Disco balls can be used as pinhead mirrors to project solar images. The math behind them is the same as for a square pinhole. [3]

References

  1. Nilsson, T. H. (1986). "Pinhead mirror: a previously undiscovered imaging device?". Applied Optics (Optica Publishing Group) 25 (17): 2863. doi:10.1364/ao.25.002863. https://doi.org/10.1364/ao.25.002863. 
  2. Nilsson, Thomy H. (1988). "Pinhead Mirrors: Imaging, Computing and the Nature of Light". Pinhole Journal 4: 2-5. 
  3. Cumming, Robert J.; Pietrow, Alexander G. M.; Pietrow, Livia; Cavallius, Maria; Petit dit de la Roche, Dominique; Pietrow, Casper; Schroetter, Ilane; Skan, Moa (2024). "Why every observatory needs a disco ball". Physics Education (IOP Publishing Ltd) 59 (2): 025012. doi:10.1088/1361-6552/ad1fa0. https://doi.org/10.1088/1361-6552/ad1fa0.