History
In the late 1960s German television producers sought out lamp developer OSRAM to create a less expensive replacement for incandescent lights for the film industry. Osram developed and began producing HMI bulbs at their request.
Philips produced a variation on the HMI, a single-ended version called MSR (medium source rare-earth). It uses a standard two-prong lampbase. In order to avoid the colour shift during use they added a secondary envelope around the gas-chamber. Several other bulb variations exist, including GEMI (General Electric metal iodide), CID (compact indium discharge; Thorn EMI, UK, since 1990 GE), CSI (compact source iodine; Thorn EMI, UK), DAYMAX (made by ILC), and BRITE ARC (Sylvania). All are variations and different names for essentially the same concept.
Within the last ten years, a lot of research has gone into making HMI lamps smaller because of their use in moving light fixtures such as those manufactured by Vari-Lite, Martin, and Highend. Philips' main contribution after this was the invention of a phosphor coating on the weld of the filament to the molybdenum foil that reduces oxidization and early failures at that point, making that area capable of withstanding extreme heat.
Multi-kilowatt HMI lights are used in the film industry and for large-screen slide projection because of their daylight-balanced light output, as well as their efficiency.
Read more about this topic: Hydrargyrum Medium-arc Iodide Lamp
Famous quotes containing the word history:
“Anything in history or nature that can be described as changing steadily can be seen as heading toward catastrophe.”
—Susan Sontag (b. 1933)
“The history of every country begins in the heart of a man or a woman.”
—Willa Cather (1876–1947)
“We know only a single science, the science of history. One can look at history from two sides and divide it into the history of nature and the history of men. However, the two sides are not to be divided off; as long as men exist the history of nature and the history of men are mutually conditioned.”
—Karl Marx (1818–1883)