Low sodium permeability glass
AssigneeGeneral Electric Company
InventorsCurtis E. Scott, Mohan Rajaram, Joseph A. Shrawder
Life of this patent
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Abstract
A glass composition, particularly well suited for use in constructing sodium containing lamp envelopes. The glass composition is comprised of silica doped with yttrium and/or cesium, preferably in combination aluminum.
Claims21
A lamp having a filament or arc discharge light source surrounded by an envelope wherein the improvement comprises said envelope being comprised of SiO.sub.2 containing at least about 10 ppm by weight of a first element selected from the group consisting of aluminum in an amount less than 10,000 ppm, lanthanum, dysprosium, niobium, erbium, and mixtures thereof, and at least one of yttrium and cesium.
A metal halide lamp having electrodes within a discharge envelope containing a fill including sodium, said envelope having substantially transparent walls comprised of SiO.sub.2, 10-10,000 ppm aluminum, and at least one of yttrium and cesium in a total quantity of at least about 25 ppm by weight.
A glass composition comprised of beneficiated quartz, about 10 to about 1000 ppm by weight of an element selected from the group consisting of aluminum, lanthanum, dysprosium, niobium, erbium, and mixtures thereof and about 20 to about 1000 ppm by weight yttrium.
A glass composition comprised of synthetic silica, about 10 to about 1000 ppm by weight of an element selected from the group consisting of aluminum, lanthanum, dysprosium, niobium, erbium, and mixtures thereof and about 20 to about 1000 ppm by weight cesium.
A glass composition comprised of beneficiated quartz, about 10 to about 1000 ppm by weight of an element selected from the group consisting of aluminum, lanthanum, dysprosium, niobium, erbium, and mixtures thereof and about 20 to about 1000 ppm by weight cesium.
A glass composition comprised of synthetic silica, about 10 to about 1000 ppm by weight of an element selected from the group consisting of aluminum, lanthanum, dysprosium, niobium, erbium, and mixtures thereof and about 20 to about 1000 ppm by weight yttrium.
A metal halide lamp having electrodes within a discharge envelope containing a fill including sodium, said envelope having substantially transparent walls comprised of SiO.sub.2 and between about 25 ppm and 10,000 ppm by weight cesium.
A lamp having a light source surrounded by an envelope, said envelope constructed predominantly of a glass comprised of:
- 50to 99.9 percent by weight SiO.sub.2
- 0,001 to 1.0 percent by weight aluminum
- 0 to 1.0 percent by weight yttrium
- 0 to 1.0 percent by weight cesium
- 0 to 0.0001 percent by weight sodium
- 0 to 0.0001 percent by weight lithium
- 0 to 0.0002 percent by weight iron
- wherein said yttrium and cesium comprise at least 0.001 percent by weight of said glass.
An article comprised of SiO.sub.2, aluminum, and at least one of yttrium and cesium having a log volume resistivity of at least about 10.50.
Dependencies are inferred from the claim text.