Cadillac Escalade Platinum Model
Cadillac's new Escalade Platinum model is the first U.S. production vehicle to use LED lighting for high- and low-beam headlamps (and the world's first LED headlamp application in annual production volumes above 10,000). Hella developed the lamps using seven separate LED arrays per side, each consisting of five light-emitting diodes from Osram Opto Semiconductor (the white parking lamp light pipe has two LEDs, the amber side marker lamp gets seven). Each array shines through a unique glass lens ground to illuminate a particular area of the road. The five outermost ones are for low-beam, the two inner round ones serve as high-beams.
Hella LED Headlamp
LED Advantages: Styling flexibility, shallow packaging depth, life expectancy 20 times greater than typical headlamps, and color temperature closest to that of sunlight (9440 degrees F, versus Xenon HID's 6740 and halogen's 5300). They also convert more electrical energy into light than the other systems do, so they're more efficient.
LED Disadvantages: Cost is the biggie; they're considerably pricier than HID. Another is cooling. While the LEDs generate way less heat, their heat doesn't radiate out as infrared light; it's conducted down into the chip and has to be cooled. Each Escalade headlamp uses a single fan to cool the arrays, and it's said to be silent and able to last the life of the vehicle. For these reasons, LED headlamps may only appear as styling statements on range-topping vehicles for the near future.