Membrane Keyboards

Membrane Keyboards

Membrane keyboards are used throughout industry, commerce and in consumer products contexts in all kinds of applications. In industry, many kinds of industrial machinery are affixed with membrane keyboards and keypads to provide technicians an avenue through which commands and settings can be programmed into electronic devices. Membrane keyboards are also very commonly chosen for use in thermostats, automobile components like electronic window controls and radios, remote controls and even for personal computing. Some membrane keyboard designs are resistant to spills, as there are no spaces between keys through which contaminants could pass and interfere with circuitry. For this reason, membrane keyboards are often employed at fast food restaurant check out counters and on home cooking appliances where exposure to spills is likely.

In general, membrane keyboards involve three layers. The top and bottom layers feature specially-positioned conductive materials. On the bottom, the conductive material is connected to the rest of the electronic device. When that conductive surface comes into contact with the conductive surface on the top layer, an electrical signal is sent while the surfaces are in contact. The center layer, called a spacer, is non-conductive and keeps the other two layers separate. Because most membrane keyboards are completely self-contained and do not feature any moving or exposed parts, they generally enjoy longer operating lives than plastic keyboards with individual keys. The most evident disadvantage inherent to most membrane keyboard design is poor ergonomic performance. Especially in the case of full-alphabet membrane keyboards for use with personal computers, the effort required to close the circuit every time a key is depressed is greater than that of a plastic keyboard. For this reason, plastic personal computer keyboards are much more popular than membrane keyboards. Some advances in membrane keyboard design have compensated for this deficiency; tactile keyboards, for example, provide users with a clear sense of whether or not a key has been depressed completely. That said, membrane keyboards perform best in settings where sufficient key depression is guaranteed without undue amounts of effort.