What Are Light Guides and How Do They Work?

When researching backlighting technologies used in keypads, you may come across light guides. Light guides are often used in mechanical and membrane keypads. They don’t necessarily produce light. Rather, light guides distribute light across the keypad’s top layer. To learn more about light guides and how they work, keep reading.

What Are Light Guides?

A light guide is a backlighting component that’s designed to propagate and distribute light across the keypad’s top layer to the areas where it’s needed. Most light guides consist of a thin layer of material. Whether a keypad uses light-emitting diode (LED) or electroluminescent (EL) backlighting, it can use a light guide as well. Once applied, the light guide will

How Do Light Guides Work?

Light guides are a relatively simple component. As previously mentioned, they consist of a film-like layer of material. The material from which they are made allows them to distribute to light. When a light guide is placed between the keypad’s buttons and backlighting, it will create an even distribution of light.

Even with a light guide, a keypad must still have backlighting. Some keypads use LED backlighting, whereas others use EL backlighting. Both LED and EL backlighting are energy efficient and long-lasting, making them popular backlighting solutions. With that said, light guides don’t produce their own light. They only distribute the light produced by LED or EL backlighting.

The LED or EL bulbs are installed on the sides of the keypad. When turned on, they’ll produce light that travels through the light guide, thus distributing it across the keypad’s top layer.

Benefits of Light Guides

With a light guide, a keypad will have brighter buttons or keys that are easier to see. Illumination isn’t needed for all applications. If you’re planning to use a keypad in a dark or otherwise dimly lit area, though, you may want to consider a light guide. This thin layer of material will propogate and distribute the light so that the keypad’s buttons or keys are easier to see.

Light guides can reduce the number of LED or EL bulbs required in a keypad. You won’t have to use as many LED or EL bulbs in a keypad if the keypad has a light guide. Therefore, a light guide can extend the life of a keypad’s backlighting.

Contrary to common belief, light guides aren’t thick or otherwise large. They are very small and consume little or no space. Light guides, in fact, can be designed with a thickness of just 100 microns. With such a small size, light guides are easy to incorporate into nearly all keypads.