Flicker-suppressed, low-power, high-pressure discharge lamp
AssigneePatent-Treuhand-Gesellschaft fuer elektrische Gluehlampen mbH
InventorsAxel Bunk, Jurgen Vom Scheidt
Life of this patent
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Abstract
To reduce flicker in low-power, high-pressure discharge lamps, the electrs, in the region in which they face each other, have wrap windings, of about 2 to 4 turns wrapped thereabout and the terminal end of the electrode has an essentially spherical end head element (19, 19', 39) melted thereon, which essentially spherical head element may be a segment of a sphere, ellipsoid-shaped or similarly formed. The electrode shaft, the wrap winding and the sphere preferably are all made of undoped tungsten, although the electrode shaft may be of a lower melting metal, such as rhenium.
Claims10
Flicker-reduced, low-power, high-pressure discharge lamp (1, 20) having a power rating of up to about 400 W, comprising
- a discharge vessel (2, 21);
- two electrodes (4, 4', 5;
- 23, 24) and connecting foils (6, 7;
- 25, 26) pinch-sealed into the discharge vessel;
- wherein each electrode includes
- a straight shaft (17, 17', 37) having an end portion forming an electrode head facing the opposite electrode and hence the discharge to be formed between the electrodes;
- a wrap winding (18, 18', 38) with more than one adjacent winding or turn on the respective end portion;
- wherein the diameter of the wrap winding wire is between about half to the entire shaft diameter of the electrode shaft (17);
- and
- means for stabilizing, in operation of the lamp, attachment of the arc between the electrodes at the end portion of the respective electrode by providing a balance between heat retention and heat radiation from the head, and hence heat balance for flicker-reduced operation,
- said stabilizing means comprising the combination of
- a solid, massive end head element (19, 19', 39) which, at least in a portion thereof facing the opposite electrode, is of essentially at least part-spherical shape, melt-connected to at least one of:
- a terminal region of the end portion of the electrode shaft;
- the last turn or winding of said wrap winding adjacent said terminal region,
- with
- a fill including mercury, a metal halide, and a noble gas located within the discharge vessel (2, 21).
Dependencies are inferred from the claim text.