US 6,888,311 B2 · Ultrahigh pressure mercury lamp with an anode configured to have a high thermal capacity

Abstract

An ultrahigh pressure mercury lamp which is small and has high light radiation intensity and moreover good color reproduction with high efficiency in which, even with a large amount of mercury added, a failure of the mercury to vaporize in the bulb part does not occur, and in which blackening of the bulb part due to wearing of the electrodes even under a large electrode load as a result of shortening of the distance between the electrodes is low is obtained by an ultrahigh pressure mercury lamp in which a bulb part of the discharge vessel made of translucent material has an essentially ovoid shape, is filled with at least 0.2 mg/mm3 of mercury and which is operated at an input wattage of at most 400 W using direct current, has the length D of the tip area of the anode and the length L of the bulb part in the direction of the tube axis of the lamp set in accordance with the relationship D≧L/2.

Claims7

Dependent claims

Ultrahigh pressure mercury lamp, comprising:

a discharge vessel having a bulb part of translucent material in essentially the shape of an ovoid and side tube parts which extend along a tube axis from opposite sides of the bulb part, the discharge vessel being filled with at least 0.2 mg/mm3 of mercury;
opposed anode and cathode electrodes disposed in the discharge vessel;
wherein the anode has a tip area and rear end, the tip area having a larger diameter than the rear end, and part of the tip area is located in a respective one of the side tube parts;
wherein the lamp is adapted for operation at an input wattage of at most 400 W using direct current, and
wherein the length D (mm) of a tip area of the anode and a length L (mm) of the bulb part in a direction of the tube axis of the lamp is set in accordance with the relationship D≧L/2.

2 more elements

Ultrahigh pressure mercury lamp, comprising:

a discharge vessel having a bulb part of translucent material in essentially the shape of an ovoid and side tube parts which extend along a tube axis from opposite sides of the bulb part, the discharge vessel being filled with at least 0.2 mg/mm3 of mercury;
opposed anode and cathode electrodes disposed in the discharge vessel;
wherein the lamp is adapted for operation at an input wattage of at most 400 W using direct current;
wherein the length D (mm) of a tip area of the anode and a length L (mm) of the bulb part in a direction of the tube axis of the lamp is set in accordance with the relationship D ≧L/2;
and
wherein a gap is provided between a part of the anode which is located inside of a respective one of the side tube parts and the respective side tube part, wherein the part of the anode which is located inside of the respective side tube part has a diameter d (mm) in the range of 0.5 ID≦d≦0.95 ID with respect to an inside diameter ID (mm) of the respective side tube part, and wherein a volume V (mm3) of the tip area of the anode with respect to the input wattage P(W) meets the condition:
V/P≧0.12 (mm3/W).

4 more elements

Dependencies are inferred from the claim text.

Ultrahigh pressure mercury lamp with an anode configured to have a high thermal capacity

Life of this patent

Ultrahigh pressure mercury lamp with an anode configured to have a high thermal capacity

Life of this patent

Abstract

Claims7