Reprographic metal halide lamps having long life and maintenance
First Claim
1. A metal halide arc discharge lamp emitting primarily in the blue, green and red portions of the visible light spectrum and not continuously across the visible spectrum and with at least a portion of the blue emission at a wavelength of about 450 nm, said lamp comprising a light transmissive, vitreous, hermetically sealed arc chamber enclosing a pair of electrodes therein which protrude into said arc chamber, said arm chamber further containing mercury, an inert gas, at least one halogen, zinc, indium, lithium, thallium, and at least one rare earth metal, wherein the amount of indium present is no greater than about 25 mole % of the total of said indium, lithium and thallium and wherein said at least one halogen is present in an amount sufficient to insure that at least said indium, lithium, thallium and at least a portion of said zinc are present as metal halides during operation of said lamp, but not in excess of that amount required for said indium, lithium, thallium, zinc and rear earth metal to be present as metal halide during operation of said lamp.
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Accused Products
Abstract
Metal halide vapor arc lamps for reprographic and projection processes emitting in the blue, green and red bands with excellent primary color separation and having long life and lumen maintenance contain mercury, zinc, indium, lithium, thallium, a halogen and a rare earth metal such as lanthanum, scandium or dysporsium in the arc tube.
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Citations
26 Claims
- 1. A metal halide arc discharge lamp emitting primarily in the blue, green and red portions of the visible light spectrum and not continuously across the visible spectrum and with at least a portion of the blue emission at a wavelength of about 450 nm, said lamp comprising a light transmissive, vitreous, hermetically sealed arc chamber enclosing a pair of electrodes therein which protrude into said arc chamber, said arm chamber further containing mercury, an inert gas, at least one halogen, zinc, indium, lithium, thallium, and at least one rare earth metal, wherein the amount of indium present is no greater than about 25 mole % of the total of said indium, lithium and thallium and wherein said at least one halogen is present in an amount sufficient to insure that at least said indium, lithium, thallium and at least a portion of said zinc are present as metal halides during operation of said lamp, but not in excess of that amount required for said indium, lithium, thallium, zinc and rear earth metal to be present as metal halide during operation of said lamp.
- 16. A metal halide arc discharge lamp emitting primarily in the blue, green and red portions of the visible light spectrum at a wavelength of about 400-480 nm, and 600-700 nm, respectively, and not continuously across the visible spectrum and with at least a portion of the blue emission at a wavelength of about 450 nm, said lamp comprising a light transmissive, vitreous arc tube having an arc chamber therein and enclosing a pair of electrodes which protrude into said arc chamber and are hermetically sealed in said arc tube, said arc chamber containing an inert gas comprising at least one noble gas, at least one halogen, mercury, zinc, indium, thallium, lithium, and at least one rare earth metal, said indium being present in an amount no greater than about 25 mole % of the combined total of said indium, lithium and thallium, with said at least one halogen being present in an amount sufficient to insure that at least said indium, lithium, thallium and at least a portion of said zinc are present as metal halide during operation of said lamp, but not in excess of that amount required for said indium, lithium, thallium, zinc and rare earth metal to be present as metal halide during operation of said lamp.
Specification