Using LED Indicators for Automotive Telltales

LED technology offers many advantages over incandescent bulbs for automotive telltales, such as higher mechanical shock and vibration resistance. Unfortunately previous LED products had insufficient optical flux for this application. This paper describes a scries of new LED indicator products that provide significantly higher optical flux than previously available indicators. The paper discusses the key factors involved with a typical telltale backlighting design including optical cavity design, selection of light diffusing films, and contrast enhancement filters and then provides benchmark results for a typical telltale design.