Keypads are the primary input mechanism for countless devices. In recent years, however, more and more device manufacturers have begun using membrane keypads. Like traditional mechanical keypads, membrane keypads feature buttons that, when pressed, trigger a command. But membrane keypads are unique because all their keys are integrated together as a single, flexible unit. Below are five things you should know about membrane keypads and how they work.
#1) They Are Resistant to Moisture and Debris
Membrane keypads are naturally resistant to the ingress of moisture and debris. Unlike mechanical keypads, the keys of a membrane keypad aren’t separate moving parts. Rather, they are produced as a single layer (upper membrane layer). As a result, you don’t have to worry about moisture, dust or debris making its way underneath the keys. As long as the membrane layer remains intact, the circuity powering the membrane keypad will remain protected from environmental-related damage. This makes membrane keypads as an attractive choice among businesses, many of which use them in factories or other production facilities.
#2) They Consist of 3 Main Layers
Although there are exceptions, most membrane keypads consist of three main layers. The uppermost layer is known as the membrane layer. Below the membrane layer is a spacer layer filled with air or inert gas. And at the bottom is another membrane layer. When you perform a keystroke, you’ll push the uppermost membrane layer into the bottom membrane layer, allowing the keypad to register your command.
#3) They Can Create Tactile Feedback
It’s a common assumption that membrane keypads can’t produce tactile feedback, but this isn’t necessarily true. Computer keypads, for example, are often created using a membrane keypad with dome switches. The presence of dome switches produces crisp, noticeable tactile feedback. Granted, other membrane keypads generally produce little or no tactile feedback, but when they are used in conjunction with dome switches, this isn’t a problem.
#4) They Have a Low Profile
When looking at examples of membrane keypads, you’ll probably discover that most if not all of them have a low profile. In other words, they feature a very shallow design that doesn’t consume much space.
#5) They Have Conductive Traces
Finally, it’s worth noting that membrane keypads are designed with conductive traces on the bottom. Each key on a membrane keypad is essentially a switch. In their default state, the key switches have an open circuit. Pressing down on a key, however, bridges the gap in the conductive traces, thus completing the circuit.