Conventional LED-based center high-mounted stop lights (CHMSL) for cars and trucks can be 0.80 in.
thick. Those that use incandescent lighting are even thicker, up to 3.2 in. A new LED version, the Chiplite LED from Schefenacker Visions Systems, Southfield, Mich. (www.schefenacker.com), is only 0.4-in. deep, which means automakers don't have to create sheet-metal pockets to support them. The thinner lights are watertight, so there's no need for sealing welds. They also snap or are taped into place, so there's no need for fasteners and associated assembly and inventory costs.
The new lights use total-internal-reflection technology to make maximum use of the available light. The LED emits light in a full 180°, but optics and diamond-turned injection-molded lenses direct light in the far-field pattern needed for good visibility. This sidesteps the need for ultrabright LEDs and gives designers more flexibility in packaging and placement.