Granted Patent B2

US 8,410,698 · App. 12/936,541 · Granted Apr 2, 2013

Abstract

Claims (33)

1. A high pressure gas discharge lamp having an efficiency equal to or greater than 90 Im/W in a steady state operation at an electrical power of 25 W, the lamp comprising:

a discharge vessel defining a sealed inner discharge space and having at least two electrodes projecting into said discharge space, said discharge space having a volume of 12-20 mm 3 and comprising a filling of a rare gas and a metal halide composition, said filling being substantially free of mercury, said metal halide composition comprising at least halides of sodium and scandium, a mass ratio of halides of sodium and scandium being in the range of 0.9- 1.5, and

an outer enclosure disposed around said discharge vessel, said outer enclosure being sealed and filled with a gas at a pressure below 1 bar.

2. A high pressure gas discharge lamp having an efficiency equal to or greater than 90 Im/W in a steady state operation at an electrical power of 25 W, the lamp comprising:

a discharge vessel defining a sealed inner discharge space and having at least two electrodes projecting into said discharge space, said discharge space having a volume of 12-20 mm 3 and comprising a filling of a rare gas and a metal halide composition, said filling being substantially free of mercury, said metal halide composition comprising at least halides of sodium and scandium, a mass ratio of halides of sodium and scandium being in the range of 0.9-1.5; and

an outer enclosure disposed around said discharge vessel, said outer enclosure being sealed and filled with a gas at a pressure below 1 bar,

wherein said discharge vessel has a maximum inner diameter in the range of 2.0 mm to 2.3 mm.

3. A high pressure gas discharge lamp having an efficiency equal to or greater than 90 Im/W in a steady state operation at an electrical power of 25 W, the lamp comprising:

a discharge vessel defining a sealed inner discharge space and having at least two electrodes projecting into said discharge space, said discharge space having a volume of 12-20 mm 3 and comprising a filling of a rare gas and a metal halide composition, said filling being substantially free of mercury, said metal halide composition comprising at least halides of sodium and scandium, a mass ratio of halides of sodium and scandium being in the range of 0.9- 1.5; and

an outer enclosure disposed around said discharge vessel, said outer enclosure being sealed and filled with a gas at a pressure below 1 bar,

wherein said discharge vessel has a wall thickness in the range of 1.5 mm to 1.75 mm.

4. The discharge lamp according to claim 1 , wherein said discharge space comprises 10-23 μg of said metal halide composition per μl of said volume of said discharge space.

5. The discharge lamp according to claim 1 , wherein said discharge space comprises 10.5-17.5 μg of said metal halide composition per μl of said volume of said discharge space.

6. The discharge lamp according to claim 1 , wherein said metal halide composition comprises at least 90 wt % halides of sodium and scandium.

7. The discharge lamp according to claim 1 , wherein said metal halide composition consists essentially of Nal and ScI 3 .

8. The discharge lamp according to claim 1 , wherein said rare gas in said discharge space is Xenon, provided at a cold pressure in the range of 10 bar to 18 bar.

9. A high pressure gas discharge lamp having an efficiency equal to or greater than 90 lmM/ in a steady state operation at an electrical power of 25W, the lamp comprising:

a discharge vessel defining a sealed inner discharge space and having at least two electrodes projecting into said discharge space, said discharge space having a volume of 12-20 mm 3 and comprising a filling of a rare gas and a metal halide composition, said filling being substantially free of mercury, said metal halide composition comprising at least halides of sodium and scandium, a mass ratio of halides of sodium and scandium being in the range of 0.9-1.5; and

an outer enclosure disposed around said discharge vessel, said outer enclosure being sealed and filled with a gas at a pressure below 1 bar,

wherein said outer enclosure is arranged at a distance (d 2 ) and filled with a filling gas such that a heat conduction coefficient

λ

d

2

 is 7.0- 225 W/(m 2 K, where λ is the thermal conductivity of the filling gas measured at 800° C. and d 2 is the distance between said outer enclosure and said discharge vessel.

10. The discharge I lamp according to claim 9 , wherein the distance d 2 is in a range of 0.2 mm to 0.9 mm.

11. The discharge lamp according to claim 9 , wherein said outer enclosure is filled with a further rare gas at a pressure in the range of 10 mbar to 700 mbar.

12. The discharge lamp according to claim 9 , wherein said outer enclosure is filled with a gas comprising at least one of Xenon and Argon.

13. A high pressure gas discharge lamp having an efficiency equal to or greater than 90 lm/W in a steady state operation at an electrical power of 25 W, the lamp comprising:

a discharge vessel defining a sealed inner discharge space and having at least two electrodes proiecting into said discharge space, said discharge space having a volume of 12-20 mm 3 and comprising a filling of a rare gas and a metal halide composition, said filling being substantially free of mercury, said metal halide composition comprising at least halides of sodium and scandium, a mass ratio of halides of sodium and scandium being in the range of 0.9- 1.5; and

an outer enclosure disposed around said discharge vessel, said outer enclosure being sealed and filled with a gas at a pressure below 1 bar,

wherein said electrodes are rod-shaped electrodes having a diameter in a range of 215-275 μm.

14. The discharge lamp according to claim 1 , wherein said metal halide composition consists essentially of Nal, ScI 3 and ThI 4 .

15. The discharge lamp according to claim 1 , wherein the volume of the discharge space volume is 12-19 mm 3 .

Assignments (6)