LEDs have been used to light the exterior of cars and trucks for over 30 years, serving as center-mounted stop lights, rear lighting, headlight accents, and even turn signals. Automotive engineers and stylists liked them for their efficiency, small size, and bright light. Now LEDs are being used more and more for interior automotive lighting as well. And lighting engineers are developing new ways to use LEDs in passenger compartments. At Federal –Mogul Corp., Southfield, Mich., for example engineers have developed NovaLens, a lens for LED lamps that takes up less space, reduces power consumption, and provides more uniform lighting.

Lamps that use the new lens can be made 12-mm thick, which saves 18 mm compared to typical LED lamp profiles. The thinner lamp, when mounted on headliner, gives passengers more headroom. This dovetails nicely with the stylizing trend towards higher seating positions and lower rooflines. The lens also  improves passenger safety as increased headroom is a safety factor in rollovers.

The NovaLens is studded with geometric features on the inside and outside that reflect and refract light from LEDs positioned at opposite sides of the lamp, and create a uniform field of illumination. The outside , for example, features several parallel optical flutes that direct light to targeted zones.

In general, LEDs draw less than 2W, depending on customer requirements, compared to 10W for equivalent incandescent bulbs. This lower electrical demand cuts CO2 emissions and helps reduce battery drain, which is important in electric vehicles and hybrids. LEDs also last more than ten times as long as incandescent bulbs and operate 95 degrees C cooler, improving thermal management, installation and styling options.