LGF (light guide film) membrane switch can offer bright and even backlighting with usual thickness of 1 mm or more; you can design custom lighting area for texts or keys and choose custom LED lighting colors (white, red, green, yellow and blue). Comparing to EL backlight, LGF (light guide film) saves EL driver IC, so circuitry for LGF membrane switch become more simple and reliable; further more, LED lighting has much longer working life  than EL light.