While not always a design requirement, many membrane switches feature a backlight. This component works to illuminate the front of the membrane switch so that the buttons are easier for users to see. But while most people are familiar with the general concept of backlighting, few know how it works in membrane switches.
Overview of Membrane Switches
Before we reveal the mechanics of backlighting for membrane switches, let’s first take a few steps back to explore membrane switches themselves. A membrane switch is an electrical switch consisting of a flexible substrate. All electrical switches are designed turn on and off a circuit. This otherwise simple design is used in a variety of applications. Membrane switches, however, feature an flexible construction, making them ideal for small devices, human machine interfaces (HMIs) and more.
The Mechanics of Backlighting for Membrane Switches
Backlighting for membrane switches works in a similar way as backlighting used in other devices, including liquid-crystal displays (LCDs). Within the membrane switch is a backlighting component that’s designed specifically for the purpose of illuminating the front of the switch. When the device in which the membrane switch is turned on, the backlighting component is activated. This produces lighting that illuminates upwards and through the upper layer of the switch.
It’s important to note that not all membrane switches require backlighting. When used in well-lit environments, users can probably see the membrane switch and its respective buttons without the need for backlighting. But if a membrane switch is used in a dim, poorly lit environment, backlighting can improve functionality and even reduce human errors. This is why it’s important to consider how and when you’ll be using a membrane switch to determine if backlighting is a smart investment.
Backlighting Solutions for Membrane Switches
All forms of backlighting for membrane switches are designed to illuminate the front of the switch’s display, thereby improving visibility for users. However, there are different types of backlighting solutions available for membrane switches, the three most common of which include light-emitting diode (LED), electroluminescent (EL) and fiber optics. LED is often preferred because of its energy-efficient properties. In small devices that aren’t powered via an external electrical outlet, for example, LED back-lit membrane switches allow the devices to run longer without the need for recharging or replacing the batteries. With that said, both EL and fiber optics backlighting are also energy efficient.
To recap, the backlighting solution for membrane switches works to illuminate the switch’s buttons. This improves user visibility and, thus, functionality.