Abstract A lead-tin-bismuth alloy is disposed within a solenoidal electric field lamp to control the mercury vapor pressure. In accordance with one embodiment of the present invention, the alloy is placed within the tip-off region of the lamp envelope. The alloy is fixed within the tip-off region by a means of wetting the alloy to a metal wire structure such as a helix or a cylindrical screen. Alternatively, the alloy may be placed on an interior surface of the envelope by first wetting the glass with a layer of indium or other metallic wetting agent. Additionally, methods for wetting the lead-tin-bismuth alloy to the metal wire include firing the alloy in contact with the wire in a hydrogen atmosphere at a sufficiently high temperature to wet the alloy to the wire. The present invention permits the control of mercury vapor pressure in solenoidal electric field discharge lamps.
A solenoidal electric field discharge lamp comprising: an evacuable, light-transmissive envelope having an interior phosphor coat; a gaseous discharge medium disposed in said envelope, at least a portion of said medium being mercury vapor; an electrically energizable toroidal magnetic core disposed within said medium, said core being electrically couplable to a ballast located at a base end of said envelope; a metallic wetting agent attached to an inner, phosphor-free surface of said envelope; and an amalgamating alloy attached over said wetting agent, for controlling mercury vapor pressure within said envelope.
Claim 2
Dependent Claim
90 words
A solenoidal electric field discharge lamp comprising: an evacuable, light-transmissive envelope having an interior phosphor coat; a gaseous discharge medium disposed in said envelope, at least a portion of said medium being mercury vapor; an electrically energizable toroidal magnetic core disposed within said medium, said core being electrically couplable to a ballast located at a base end of said envelope; a metallic wetting agent attached to an inner, phosphor-free surface of said envelope; and an amalgamating alloy attached over said wetting agent, for controlling mercury vapor pressure within said envelope.
Claim 3
Dependent Claim
25 words
The lamp of claim 1 in which the point of attachment of said alloy is at a position opposite the base end of said envelope.
Claim 4
Dependent Claim
21 words
The lamp of claim 1 in which said metallic wetting agent is selected from the group consisting of indium and gallium.
Claim 5
Dependent Claim
17 words
The lamp of claim 1 in which said alloy comprises a mixture of lead, bismuth and tin.
Claim 6
Dependent Claim
20 words
The lamp of claim 4 in which said lead, bismuth and tin are present in the ratio 32:52.5:15.5 atomic percent.
Claim 7
Dependent Claim
35 words
The lamp of claim 1 in which the amounts of mercury and alloy are selected so as to maintain the mercury vapor pressure of an operating lamp at between approximately 5 and approximately 10 millitorr.