High efficacy metal halide lamp with praseodymium and sodium halides in a configured chamber
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsHuiling Zhu, Shin Ukegawa, Hiroshi Nohara, Jakob Maya
Life of this patent
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Abstract
An arc discharge metal halide lamp for use in selected lighting fixtures having a discharge chamber with light permeable ceramic walls of a selected shape about a discharge region of a selected volume. A pair of electrodes are supported in the discharge region separated from one another by a separation length. The separation length is in a ratio to the effective inner diameter that is greater than four. Ionizable materials are provided in the discharge region comprising a quantity of mercury in a ratio to the discharge region volume that is less than 4 mg/cm3, a noble gas, praseodymium halide, and sodium halide.
Claims20
An arc discharge metal halide lamp for use in selected lighting fixtures, said lamp comprising:
- a discharge chamber having light permeable walls of a selected shape bounding a discharge region of a selected volume through which walls a pair of electrodes are supported in said discharge region separated from one another by a separation length, said walls having an effective inner diameter over said separation length in directions substantially perpendicular to said separation length with a ratio of said separation length to said effective inner diameter being greater than four;
- and
- ionizable materials provided in said discharge region of said discharge chamber comprising mercury in a ratio of a quantity thereof to said discharge region volume that is less than 4 mg/cm3, a noble gas, and at least two metal halides including praseodymium halide and sodium halide.
A lighting system including a metal halide lamp that maintains substantial color constancy over a range of lamp operating powers at and below full rated operating power, said system comprising:
- an operating circuit for metal halide lamps capable of providing a strike voltage and an operating voltage to initiate and subsequently operate a metal halide lamp while providing selected operating electrical currents therethrough during such operation;
- and
- a metal halide lamp having electrodes in a discharge chamber positioned therein electrically interconnected to said operating circuit and which discharge chamber contains at least two metal halides including praseodymium halide and sodium halide to thereby emit light during operation of substantially identical hue at a first operating power set by a first selected operating current and at a second operating power set by a second selected operating current with said second operating power being approximately half of said first operating power.
Dependencies are inferred from the claim text.