|This article requires additional photographic illustration — photos with clean metal plates would be desirable|
Craig C. Madsen|
Daniel B. Stewart
|Peak force||35 g, 60 g, 130 g|
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.
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.
All known keycaps are dye sublimated. Except for those with replaceable key-legends, which are pad printed.
Only one keyboard is known to have been made with these switches: the BET-KB
- Patent US4479111 — Photo-Optical Switch Apparatus
- Patent US4301345 — Key switch actuation by torsion spring (Has force curves for the horizontally disposed biasing spring)