If you keep up with our blog here at Nelson-Miller, you should have a strong understanding of the concept behind membrane keypads. Unlike standard “computer keypads,” membrane keypads are comprised of a single piece of material, which is usually made of rubber. This allows for improved ergonomics, greater resistance to water and moisture, and a higher level of durability. But there are actually two different sub-types of membrane keypads: flat-panel and full-travel. Today we’re going to take a closer look at these different types, revealing their unique characteristics.
Flat-panel membrane keypads are typically designed with three layers. The upper layer features the printed on the front and electrical conductive stripes printed on the back. The middle layer is a spacer, meaning its sole purpose is to prevent the upper and bottom layers from touching. On the back of this layer is another set of conductive stripes, which are typically printed perpendicular to the stripes on the upper layer. When a user presses a key, the stripes connect to form a grid. Subsequently, this allows the human machine interface (HMI) or device to register the keypress.
Due to their unique design, flat-panel membrane keypads lack physical tactile feedback. Other types of membrane keypads may produce vibrations when a key is pressed. Flat-panel keypads, however, do not. With that said, some of the newer models may use lights and/or sound to produce non-physical tactile feedback.
Full-travel membrane keypads, on the other hand, are made of a single piece of rubber or plastic instead of three layers. The actual keys are “plungers,” so when the operator presses down on a key, it creates contact in the switch matrix. This allows for a simple yet effective mechanism in which the keys are integrated directly into the pad.
So, which type of membrane keypad should you choose? You really can’t go wrong with either flat-panel or full-travel. They are both highly effective designs that offer all of the attractive benefits of membrane keypads. Flat-panel membrane keypads, however, are typically used in appliances and other larger applications, whereas full-travel are used in portable keyboards.