From microwave ovens and air conditioner control panels to television remotes, computers and even smartphones, membrane switches are used in a wide variety of settings. Like all switches, they allow users to control certain devices by pressing a button. However, membrane switches are unique in their construction, featuring subtle nuances that shouldn’t be ignored. To learn more about membrane switches and the mechanics that power them, keep reading.
What is a Membrane Switch?
A membrane switch is essentially a multilayered switch consisting of multiple components that’s activated by touch. It’s used to connect and disconnect devices, allowing the operator to control the flow of electricity to the respective device. What makes a membrane switch different from a traditional switch, however, is its construction. Traditional switches are made with copper or plastic components, while membrane switches are made with a printed circuit board in which graphic, silver ink and/or copper is used. This allows for greater sensitive to touch, enhancing its functionality and overall user satisfaction.
Membrane Switch Design
While the design specifications of membrane switches vary depending on the manufacturer, most consist of between four and seven layers. The top layer is a graphic overlay that provides a visual representation of the switch’s buttons. Underneath this layer is a printed circuit board that can also function as a flex circuit made of either copper and/or polyimide. The layers in a membrane switch are typically constructed with pressure-sensitive adhesive, allowing it to withstand the constant use of everyday wear. However, come companies may opt for a cheaper solution, such as a physical keyboard housing.
Of course, connection between the two traces is critical when designing a membrane switch. Without this connection, there’s simply no way for the membrane switch to function as intended. So, how is contact made between the two traces? Normally, this connection is made either through a printed shorting pad (the preferred choice among many manufacturers of membrane switches), or a standing metal dome.
Two Types of Membrane Switches
There are generally two primary types of membrane switches: non-tactile switches, which offer the benefit of increased longevity and a lower production cost, or tactile switches, which cost more and have a shorter lifespan but offer the benefit of improved accuracy and user satisfaction. Tactile switches are often the preferred choice because of the positive impact tactile feedback has on a user’s accuracy.
Hopefully, this will give you a better understanding of membrane switches and the mechanics which power them.