Claims
- 1. An improved beam mode fluorescent lamp wherein said lamp has an enclosing light transmissive lamp envelope having an interior surface; a lamp base with a socket therewithin coupled to said envelope to form a complete enclosure with said envelope; a phosphor coating deposited on said interior surfaces of said envelope for converting ultraviolet radiation to visible radiation; a fill of noble gas and mercury vapor within said enclosure; a first filament covered with an alkaline earth coating having a pair of opposed ends; a first set of filament connecting leads for coupling said ends to said socket; a second filament covered with an alkaline earth coating having a pair of opposed ends; a second set of filament connecting leads for coupling said ends of said second filament to said socket; and said alkaline earth coatings having a tendency to decompose into elemental form upon application of heat thereto; wherein the improvement comprises:
- an electrically floating conductive grid means; wherein said grid means is a singular cylindrical structure which substantially surrounds both of said filaments and is closed off at one end adjacent said filaments and is closed off at an opposite end by a portion of said lamp base to provide a mesh that is interposed between said filaments and said phosphor layer such that particles of said decomposing coatings cannot diffuse unobstructed form said filaments to said phosphor layer; and such that said grid means during operation of said lamp acquires a negative potential with respect to the plasma and selectively acquires positively ionized particles from said decomposing alkaline earth coating.
Parent Case Info
This is a continuation of co-pending application Ser. No. 136,037, filed on Dec. 21, 1987, now abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
2812465 |
Germeshausen |
Nov 1957 |
|
4408141 |
Byszewski et al. |
Oct 1983 |
|
4521718 |
Byszewski et al. |
Jun 1985 |
|
Continuations (1)
|
Number |
Date |
Country |
Parent |
136067 |
Dec 1987 |
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