An Introduction to PCB Membrane Switches

Jul 29, 2020

NormaTec membrane switch with embossed keys, a lens, and gradient color patterns

Membrane switches are used in a variety of electronic devices. Characterized by the use of a flexible substrate, they offer a low-profile design that’s highly versatile as well as durable. There are different types of membrane switches, however, one of which is being printed circuit board (PCB). For a better understanding of PCB membrane switches and how they work, keep reading.

What Is a PCB Membrane Switch?

A PCB membrane switch is a special type of membrane switch that features a printed circuit board. Like all membrane switches, they are made of a flexible substrate. They typically contain two conductive contacts, both of which are separated by a spacer layer consisting of air. A flexible material is then used to connect to these conductive contacts.

PCB membrane switches are distinguished from other types of membrane switches by their use of a printed circuit board. Most PCB membrane switches feature a printed circuit board made of copper-clad cloth or resin-infused fiber

PCB Membrane Switches vs Flex Membrane Switches: What’s the Difference?

The terms “PCB membrane switch” and “flex membrane switch” are often used interchangeably when referring to electrical switches designed with a printed circuit board. While they both use printed circuit boards, though, they are two unique switching solutions.

A flex membrane switch is essentially a variant of a PCB membrane switch. It uses dielectric material rather than copper-clad cloth or resin-infused fiber. What does this mean exactly? With dielectric material, flex membrane switches are easier to manufacture. Therefore, they cost less than their PCB membrane switch counterparts.

Backlighting for PCB Membrane Switches

Whether it’s a standard PCB membrane switch or a flex membrane switch, both types supports the use of backlighting. Backlighting consists of a lighting element that, when activated, illuminates the switch’s buttons.

PCB membrane switches support several types of backlighting. Light-emitting diode (LED) is one of the most common types of backlighting used in PCB membrane switches. It’s long-lasting, energy efficient and offers strong illumination capabilities. LED backlighting can even be used with light guides to provide even distribution of light.

The light guides don’t actually produce their own light. Rather, they evenly distribute the light produced by the LED bulbs. Light guides are designed to prevent contrast problems in which some areas are brighter than others.

A PCB membrane switch is a type of electrical switching solution that uses a printed circuit board with a flexible substrate.

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