Editing Burroughs Opto-Electric

{{TODO photo|more=true|reason=photos with clean metal plates would be desirable}}

{{Infobox dswitch
| name              = Burroughs opto-electric with torsion spring
| image name        = BOE-SwitchActuation.png
| manufacturer      = [[Burroughs]]
| product code      = 
| switch type       = [[Switch terminology#Parabolic Switch|Parabolic]]
| inventor          = Craig C. Madsen<br/>Daniel B. Stewart<br/>James Andree
| contact mechanism = [[Optoelectronic]]
| lifetime          = Unknown
| force graph name  = BOE-ForceGraph.png
| peak force        = 35 g, 60 g, 130 g
| patents           = [http://www.google.com/patents/US4301345 US4301345] (1980)<br>[http://www.google.com/patents/US4479111 US4479111] (1982)
}}

==History==
Developed by [[Burroughs]] in the early 1980s as a "low profile", "tactile" and consistent switch using an optoelectronic switching mechanism (note that it's not tactile in the modern sense). Besides being a rare optoelectronic switch, this switch uses a horizontally disposed biasing spring which gives a very unique feel to the key actuation.

Only one keyboard is known to have been built with these switches for the [[Burroughs]] by [[Kokusai Electric]]: the [[BET-KB]].

<gallery widths=300px heights=300px>
File:BOE-ExplodedView.png          | Exploded view of switch.
File:BOE-GreyKeycap-CapsLock.jpg   | Dirty grey dye sublimation keycap, and underside of cap locks key.
File:BOE-BlueKeycap-Legendable.jpg | Dirty blue legendable keycap, pad printed.
File:BOE-Sliders-DirtyPlate.jpg    | Single spring splider, view of torsion spring. Metal plate is both very dirty and heavily corroded.
File:BOE-DoubleSpringSlider.jpg    | Double spring slider, approximately 130 g.
File:BOE-Underside-Slider.jpg      | Underside of sliders attached to metal plate.
File:BOE-LED-Photoresistor.jpg     | LED and photo resistor for each torsion spring slider.
File:BOE-Keycap-profile.jpg        | Clean keycaps, top row uses heavy switches, approximately 130 g.
</gallery>

==Keyfeel==
Very smooth slider, and very consistent spring. Since the optoelectronic is contact-less, it plays no part in the keyfeel. The horizontally disposed biasing spring provides a very unique key feel, as the force to actuate actually decreases past a certain point in the key press.

==Keycaps==
All known keycaps are dye sublimated. Except for those with replaceable key-legends, which are pad printed.

==Availability==
Only one keyboard is known to have been made with these switches: the [[BET-KB]]

==Patents==
* [http://www.google.com/patents/US4479111 Patent US4479111 — Photo-Optical Switch Apparatus]
* [http://www.google.com/patents/US4301345 Patent US4301345 — Key switch actuation by torsion spring] (Has force curves for the horizontally disposed biasing spring)

[[Category:Burroughs switches]]
[[Category:Parabolic switches]]
[[Category:Optoelectronic switches]]
[[Category:List of all keyboard switches]]