The first lamp to use halogen gas (chlorine) was patented in 1882, but the first commercial halogen lamp that used iodine as a halogen gas wasn’t patented until 1959 by General Electric. It was developed by Elmer Fridrich and Emmet Wiley, who worked at General Electric, and were experimenting with heat lamps, trying to find a way to raise incandescent lamp temperatures while reducing the bulb wall blackening. They found that by adding iodine, they were able to produce an intense, natural-looking light. For their breakthrough they were rewarded with $100 in GE stock.
Photo courtesy of Stefan Wernli.
