BACKLIGHTING
Backlighting has always been a problem for membrane switch manufacturers, the opaque silver pads preventing full function lighting of the overlay from the rear of the switch. A variety of approaches have been used, often with banks of LED’s or reflector boxes. Cut outs have been required in the backing panels.
Electronic Imaging offers two forms of effective backlighting, Electroluminescent, and Lumitex Woven Fibre. These are both thin film (less than 200mic-.008″) panels and are laminated within the switch directly below the overlay for full function backlighting.
There are advantages for each product, and also many environmental considerations. For instance, in both products, the inclusion of the backlighting layer has a noticeable impact on the tactile feel – it deadens that “click” when the button is pressed.