Used in a wide variety of industries ranging from healthcare and aerospace to military and manufacturing, membrane switches play a key role in the function of electronic devices. Like all switches, they are designed to turn on and off device through a convenient interface. However, membrane switches differ from mechanical switches by featuring a circuit printed on PET or ITO. To learn more about membrane switches and how they are constructed, keep reading.
While there are dozens of different types of membrane switches, most are designed in the same manner. They contain a top membrane layer, followed by a space layer underneath, a printer circuit later, adhesive layer, and then a rail filler. With that said, some membrane switches may also feature shielding if the switch will be used in extreme environments, such as outdoors. In this case, a two-circuit membrane switch may be used instead of a conventional single-circuit switch.
Additionally, some membrane switches uses different materials on the actual circuit. Rather than silver, for instance, copper and polyimide is used in membrane switches for extreme environments and applications. Also known as “Kapton” circuits, they have stronger current capacities and increased resistance to the intrusion of moisture and dust. For these reasons, companies often choose Kapton circuits when the membrane switch will be used outdoors or in other extreme environments. While they usually cost more than traditional silver-printed circuits, the end result is a stronger and more durable membrane switch that can withstand the elements.
We’ve talked about this before, but it’s worth mentioning again that membrane switches offer several benefits over mechanical switches, one of which is a smaller and more compact design. Because they are printed on a flexible layer, they tend to have a smaller profile; thus, allowing them to be used in applications where mechanical switches simply aren’t possible. And membrane switches also boast a higher level of resistant to moisture, dust, dirt and debris.
When choosing a membrane switch, you need to consider the backlighting. The two most common backlighting options for membrane switches are light guides and light-emitting diodes (LEDs), both of which are excellent choices. However, there are other backlighting options from which to choose. Membrane switches support a wide variety of backlights, including fiber optics and electroluminescent (EL).
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