Short arc fluorescent lamp
First Claim
1. An improved short-arc fluorescent lamp of the type comprising two electrodes disposed in a gas and contained within and at opposite ends of a substantially tubular, light-transmissive evacuable envelope;
- wherein, as an improvement;
said gas comprises inert gases at a pressure between approximately 0.2 torr and approximately 2.0 torr; and
each of said electrodes comprises a heated filament coated with an electron emissive material and disposed within a substantially hollow cathode element which is adapted to provide a diffuse termination for an electric discharge, said cathode element having at least one aperture therein for electron emission therefrom, each of said electrodes having a dimension along the axis of the envelope no greater than its dimension across the envelope, whereby the arc distance is lengthened; and
said tubular envelope has a large diameter substantially half its length, whereby the envelope area is increased and phosphor loading is lessened.
0 Assignments
0 Petitions
Accused Products
Abstract
A short arc fluorescent lamp comprises an envelope having dimensions compatible with existing incandescent lamp luminaires. A radio frequency power supply, enclosed within the lamp base structure, reduces anode voltage drop to increase lamp efficacy. Cathode voltage drop and sputtering are reduced by compact hollow cathode assemblies, including centrally disposed filaments, which are positioned at opposite ends of a tubular envelope assembly having a large ratio of diameter to length. Diffuse cathode emission allows operation with low pressure, low atomic weight fill gas which further increases luminous efficiency.
-
Citations
36 Claims
-
1. An improved short-arc fluorescent lamp of the type comprising two electrodes disposed in a gas and contained within and at opposite ends of a substantially tubular, light-transmissive evacuable envelope;
- wherein, as an improvement;
said gas comprises inert gases at a pressure between approximately 0.2 torr and approximately 2.0 torr; and each of said electrodes comprises a heated filament coated with an electron emissive material and disposed within a substantially hollow cathode element which is adapted to provide a diffuse termination for an electric discharge, said cathode element having at least one aperture therein for electron emission therefrom, each of said electrodes having a dimension along the axis of the envelope no greater than its dimension across the envelope, whereby the arc distance is lengthened; and said tubular envelope has a large diameter substantially half its length, whereby the envelope area is increased and phosphor loading is lessened. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
- wherein, as an improvement;
-
23. A lamp comprising, in combination:
-
a substantially tubular, light-transmissive, evacuable envelope; an inert gas at a pressure between approximately 0.2 torr and approximately 2.0 torr disposed within said envelope; mercury vapor disposed within said envelope; electrodes, disposed in opposite ends of said tubular envelope, each electrode comprising a heated filament coated electron emissive material disposed within substantially hollow electron emitting means, which means function to provide a diffuse termination for an electric discharge; means for producing an alternating electric field, at a frequency above approximately 1 kHz, between said electrodes; and means for limiting current flow between said electrodes. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
-
-
31. A lamp electrode comprising, in combination:
-
a heated filament; an electron emissive material disposed on said filament; an open-ended, slotted cathode element disposed around said filament; an open-ended, slotted heat shield disposed around said cathode element, the edges of a slot in said cathode element being aligned with and attached to the edges of a slot in said heat shield to define therebetween an opening for diffuse electron emission. - View Dependent Claims (32, 33, 34, 35, 36)
-
Specification