Membrane switches are becoming increasingly more popular than their mechanical counterpart. They are characterized by the use of a conductive ink, such as copper, silver or graphite, printed on PET or ITO. Membrane switches perform the same function as a traditional electrical switch, allowing the operator to turn on or off a circuit. What makes it different, however, is that it uses a conductive ink that allows for a smooth, dust-resistant surface. But there are a few things to consider when designing a membrane switch.
Overlay Material
One of the first things to consider when designing a membrane switch is the overlay material. While there are always exceptions to this rule, most membrane switches use either polycarbonate or polyester for the graphic overlay. The actual material is transparent initially. It’s not until the graphics are printed on the opposite side that the overlay becomes a solid, nontransparent color.
Finish
In addition to the overlay material, you should also consider the finish used on a membrane switch. Finishes are typically used strictly for aesthetic purposes, meaning they serve no functional use or benefit. Nonetheless, they can still enhance user satisfaction by making the switch more attractive. Some popular finishes used in membrane switches include embossing, colors and textures.
Backlighting
Of course, you’ll also need to choose a backlight for your membrane switch. Backlights crea te illumination, allowing the operator to see the buttons more easily. We’ve talked about this before, but it’s worth mentioning again that there are three main backlighting options used in membrane switches: light-emitting diodes (LEDs), optical fiber, and electroluminescent. LEDs are inexpensive and energy efficient, but they tend to create bright lights, making them a poor choice for overall backlighting. Optical fiber, however, is a better choice that can last for 10,000 to 100,000 hours. EL lamps are also an excellent choice, with a half life of roughly 3,000 to 8,000 hours (varies depending on the quality of phosphor used).
Ultraviolet (UV) Coating
If you intend to use the membrane switch outdoors, you should consider using an ultraviolet (UV) coating. Prolonged exposure to the sun’s UV rays can cause the overlay to fade or even damage in severe cases. Thankfully, there’s a simple solution to this problem: UV coating. Once added to the membrane switch, the UV coating will block out the sun’s UV rays, protecting the switch from sun fading and damage.
