Fluorescent lamp with cathode heat switches
AssigneeGeneral Electric Company
InventorsPeter V. Dembowski, Quentin D. Dobras
Life of this patent
Estimating the term…
Abstract
A rapid start fluorescent lamp comprising a pair of cathode mounts each having a pair of lead-in wires for cathode heating current, and a thermal switch to turn off the heating current after sufficient cathode heating for the lamp to operate. A third lead-in wire in each mount bypasses the thermal switch and is used for heating the cathodes to activate them during manufacturing.
Claims7
A rapid start type of fluorescent lamp comprising:
- an elongated bulb;
- a pair of lamp stems sealing the respective ends of said bulb;
- each lamp stem comprising a cathode mount having a cathode, first and second lead-in wires extending through said cathode mount for providing operating heating current to the cathode, and a third lead-in wire extending through said cathode mount and connected to said cathode;
- one of said first and second lead-in wires having a thermally operated switch associated therewith and disposed in operating relationship with said third lead-in wire for turning off said cathode heating current in response to heat from the cathode;
- and said third lead-in wire comprising a current path bypassing said switch.
A method of activating a fluorescent lamp cathode in a lamp having a pair of first and second lead-in wires for providing operating current to the ends of and through the cathode, and a thermally operated cathode current cutout switch interposed in series with said first lead-in wire, wherein the improvement comprises the steps of providing a third lead-in wire connected to the end of the cathode to which said first lead-in wire provides current, and applying a source of cathode activation current to said second and third lead-in wires.
Dependencies are inferred from the claim text.