Bauernfeind prism
A Bauernfeind prism is a type of reflecting prism used to deviate a beam of light by 45° to 60°, depending on its construction, while neither flipping nor rotating the image.[1] It is named for its inventor, the German expert of geodesy [[{{{1}}}]][].[2]
The beam is reflected twice in the prism, with one reflection happening at less than the critical angle, therefore the prism requires a reflective coating for this surface to be usable in practice.
A Bauernfeind prism with 45° beam deviation is also known as a half-penta prism or semipentaprism.[3][4] A Bauernfeind prism is used together with a Schmidt roof prism to form a Schmidt–Pechan prism.
Applications
The Bauernfeind prism is commonly used in microscope tubes and in geodesy to deviate the path to the eyepiece in order make the device more ergonomic.[5]
More recent applications are glasses that deflect the viewing angle either downwards (for relaxed reading or watching TV[6]), or upwards (for watching a climber while belaying[7]).
References
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- ↑ Optik: Physikalisch-technische Grundlagen und Anwendungen, p. 475, at Google Books (German)
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- ↑ [[{{{1}}}]][]
