Strategically placing lights inside an input device to illuminate the backs of keys and functions is a technique, referred to as backlighting. It makes keys and legends easier to read and products much more marketable. Careful consideration of the trade-offs between the different backlighting applications, the product in design, and environmental requirements are all crucial elements to the product's performance, reliability, and fitness for use. All materials are permeable to some degree. Sealing, therefore, as defined by Advanced Input Devices is to prevent the egress into an enclosure or layers of a keypad by moisture, liquids, chemicals, or particles.
All materials are permeable to some degree.
Sealing, therefore, as defined by Advanced Input Devices is to prevent the egress into an enclosure or layers of a keypad by moisture, liquids, chemicals, or particles. Imagine swapping peripherals at will without having to reboot the system.