A binoviewer is an optical device designed to enable binocular viewing through a single objective, primarily to reduce fatigue when peering down a single objective.
Design
- Eyepiece
- Compensation slide
- Prism
- Beam splitter
- Body
- Barlow lens
In contrast to binoculars and stereo microscopes, which provide independent optical paths to each eye, both images in the binoviewer are produced by the same objective1: 98 and do not differ except for aberrations induced by the binoviewer itself. Because the eyes and brain still process the image binocularly, it provides a false stereoscopic view from a fundamentally monocular design.
A binoviewer consists of a beam splitter which splits the image provided by the objective into two identical (but fainter) copies,1: 98 and a system of prisms or mirrors that relay the images to a pair of identical eyepieces. The two eyepieces serve to provide greater viewing comfort.2: 196 3: 87
The binoviewer was first popularized by a design credited to Francis Herbert Wenham around 1860.2: 197 41: 94 The binoviewer was refined using roof prisms by Jentzsch and Siedentopf in the 1910s.5: 38 : 47
Applications
Binoviewers are a standard component of laboratory microscopes and are also used with optical telescopes, particularly in amateur astronomy.
Trinocular splitters are also used, where a camera is to be attached as well.
References
References
- Linssen, E. F. (1952). Stereo-photography in Practice. London: The Fountain Press.
- Bradbury, S. (1968). The Microscope: Past and Present. Pergamon Press.
- Payne, Bryan Oliver (1957). Microscope Design and Constructions (2nd ed.). York: Cooke, Troughton & Simms, Ltd.
- Nothnagle, Paul E.; Chambers, William; Davidson, Michael W. "Introduction to Stereomicroscopy". MicroscopyU. Nikon. Retrieved 8 August 2025.
- Belling, John (1930). The Use of the Microscope. McGraw-Hill.