Xymox Technologies, Inc. is an American manufacturer whose product range includes membrane assemblies. The W.H. Brady Co. (now Brady Corporation) introduced a membrane switch product line in 1978 called LiteTouch; in 1979, this product line was given its own division, dubbed Xymox. Brady divested Xymox in 1993.
Early details are obscure. Xymox themselves list two theories of the origin of the Xymox name; one of them is that “Xymox” stands for “X-Y matrix or common ground (X)”, illustrated with a pair of conductive single-layer FPCs. The earlier units were conductive only. Xymox’s Celebrating 40 Years of Excellence page notes that capacitive sensing was introduced in 1985. The following excerpt is from an article in Electronic Design magazine from 1985 (Alphanumeric keyboards, Mike Mullin, Electronic Design 33, 21st November 1985) and gives a few details from that time:
Pad-capacitive and membrane switching technologies merge in the switching core units developed by the Xymos Division of W.H. Brady Co. (Milwaukee). Though the keyboards use membrane technology primarily, they do incorporate a foam pad between the two conductive membranes. The pad serves as a dieletric; thus the actual switching action is accomplished through capacitive coupling. Xymos makes neither actuators nor full-travel key assemblies, but its switching cores can be configured to work with a variety of them.
Note that the “Xymos” spelling is a mistake.
W.H. Brady Co. capacitive membranes can be found in the HP C1405A keyboard, through which W.H. Brady was rediscovered.
Xymox continue to manufacture both conductive and capacitive products.
Patents filed by Brady in relation to capacitive matrix sensing include:
|RC Array||US 4412209||1981-11-20||1983-10-25|
|Membrane switch||US 4415781||1981-11-20||1983-11-15|
|Transparent capacitance membrane switch||US 4431882||1982-08-12||1984-02-14|
|Capacitance membrane switch||US 4562315||1984-09-20||1985-12-31||Covers the assembly in HP’s C1405A|