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:
“I am not a literary man.... I am a man of science, and I am interested in that branch of Anthropology which deals with the history of human speech.”
—J.A.H. (James Augustus Henry)
“I am ashamed to see what a shallow village tale our so-called History is. How many times must we say Rome, and Paris, and Constantinople! What does Rome know of rat and lizard? What are Olympiads and Consulates to these neighboring systems of being? Nay, what food or experience or succor have they for the Esquimaux seal-hunter, or the Kanaka in his canoe, for the fisherman, the stevedore, the porter?”
—Ralph Waldo Emerson (1803–1882)
“All objects, all phases of culture are alive. They have voices. They speak of their history and interrelatedness. And they are all talking at once!”
—Camille Paglia (b. 1947)