Membrane switches, mechanical switches, human machine interfaces (HMIs) and other devices often require backlighting. Backlighting will illuminate the device from behind so that its keys or buttons are easier to see.
While all backlighting is designed to illuminate the respective device from the “back” of the device, there are different backlighting technologies. Electroluminescent (EL), for instance, is a common backlighting technology. What is EL backlighting exactly, and when should you choose it?
An Introduction to EL Backlighting
EL backlighting leverages the electroluminescent properties of phosphor compounds to generate light. Thereare certain materials that release photons when exposed to an electrical current. Known as electroluminescent materals, they are commonly used in backlighting and traditional lighting systems.
Phosphor is an electroluminscent material that shares these same effects. It generates light by releasing photons when exposed to an electrical current. EL backlighting typically features two conductive layers. Between these two conductive layers is a third layer consisting of phosphor compounds. When a direct current (DC) voltage is applied to one of the conductive layers, it will travel through the phosphor compounds.
When to Choose EL Backlighting
You should typically choose EL backlighting for applications in which the device doesn’t require constant illumination. Some devices will produce illumination all the time. When you turn on one of these devices, they’ll begin to generate light — and they won’t stop until you turn off the device. EL backlighting isn’t a good choice for devices such as this. Rather, you should choose EL backlighting for devices that only require temporary or intermittient lighting.
EL backlighting contains phosphor compounds. Phosphor is an electroluminescent material, meaning it releases photons when exposed to an electricalcurrent. Phosphor compounds, however, are susceptible to decay. Over time, phosphor compounds may lose their ability to generate light. This is especially true in backlighting applications where the phosphor compounds are exposed to high voltages.
You can still choose EL backlighting for devices. EL backlighting, in fact, is a popular all-around choice because of its bright light and energy-efficient properties. You can rest assured knowing that it will produce bright light while consuming a minimal amount of energy.
But for applications that require constant lighting, you may want to choose an alternative backlighting technology. EL backlighting is susceptible to decay. As its phosphor compounds begin to decay, EL backlighting may fail to generate a sufficient amount of light.