Editing Membrane keyboard (section)

==History==
Membrane keyboards are not a new idea. [[Datanetics]] developed a complex membrane assembly design in 1968, as found in [https://www.google.com/patents/US3594684 US patent 3594684] (filed 1969, issued 1971). This design used many more layers than are found in modern keyboards, and included gold plating for reliability. Instead of continuing down this path, Datanetics decided to place the membrane inside the switch, a design which became the discrete [[Datanetics DC-50 series|DC-50 series]].

<gallery widths=250 heights=187>
File:Datanetics membrane switch historical notes.jpg | Datanetics membrane keyboard history
File:Datanetics membrane -- side view.jpg            | Side view of Datanetics membrane assembly
</gallery>

[[Mitsumi KSD Type]] has been found in an [[Atari 800]] computer dated December 1982. KSD Type is a PCB–membrane hybrid, using a PCB for the stationary portion of the circuit, and two membrane layers above that for the movable portion of the circuit (trace layer and spacer layer).

D'Milo Hallerberg reported that [[Hi-Tek Corporation]] were developing membrane keyboard technology around the time that they were acquired by [[NMB]]'s parent company Minebea, ca. 1983.<ref name="DMilo" /> It is possible that this went on to become the membrane version of the RT-101 series. IBM introduced the [[IBM Enhanced Keyboard]] in 1985, bringing [[buckling spring]] and membrane technology together; this design was filed in 1983 as [http://www.google.com/patents/US4528431 US patent 4528431], granted in 1985.

Membrane technology did not become commonplace until the 90s. BTC was using rubber dome keyboards in the 90s, but even in 1994 with the [[BTC 51X9 series]] was still using a PCB for the matrix. Apple's first full-size membrane keyboard was the [[AppleDesign Keyboard]], introduced in 1994 to replace the mechanical [[Apple Extended Keyboard II|Extended Keyboard II]]; for cheaper machines, the membrane-based [[Apple Keyboard II]] had already been around since 1990. By the 2000s, rubber dome over membrane keyboards were a given.