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US 6,605,888 B1Granted
Metal halide lamp with enhanced red emission, in excess of a blackbody
AssigneeMatsushita Electric Works, Ltd.
InventorsJohn F. Waymouth, Timothy Lee Kelly, Stefaan Maria Lambrechts, Jakob Maya
Life of this patent
Estimating the term…
Abstract
A metal halide lamp having excess amount of red radiation, well beyond a tungsten halogen lamp of the same color temperature. The deep saturated red being accomplished with reasonable efficacy utilizing a mixture of sodium and rare earth halides, additional broadening of the Na “D” lines and filtering out the yellow radiation at about 590 nm. The red radiation is comparable to the commercially available white high pressure sodium lamp red radiation.
Claims9
A high pressure electric discharge lamp comprising:
- an arc tube with an electrode sealed at each end thereof and filled with a mixture of metal halides, mercury and a rare gas;
- a heat shield attached to each of ends of said arc tube to raise the cold spot temperature and the salt vapor pressure in the arc tube;
- and
- means to filter radiation centered around 590 nm disposed around said arc tube to filter radiation centered around 590 nm, said means having a full width centered around 590 nm that varies between 10 nm and 100 nm;
- and
- an outer jacket disposed around said arc tube and said filter means and a current conveying means provided to carry appropriate current to said electrodes.
3 more elements
A high pressure lamp comprising:
- a ceramic arc tube with an electrode at each end thereof, said tube being filled with a mixture including excess metal halides, mercury and rare gas, the radiation of said lamp being white and close to the blackbody, the wall loading of said tube being increased from a customary of 22W/cm2 to about 30W/cm2 to increase the broadening of the sodium “D” lines;
- and
- filter means with said arc tube to filter out radiation centered around 590 nm, said filter means having a filter width with a full width at half maximum that varies between 10 nm and 100 nm.
Dependencies are inferred from the claim text.