Lamp employing a silica modified phospher
Abstract
Abstract Silica-modified, lead-activated calcium tungstate phosphor compositions having a Ca:W ratio of substantially 1 and substantially all calcium and tungsten present as calcium tungstate are disclosed wherein the phosphor contains, as a modifier, silicon dioxide in an amount sufficient to produce increased brightness to about 0.03 mole per mole of calcium tungstate and as an activator, lead in an amount sufficient to produce luminescence to about 0.03 mole per mole of calcium tungstate. A process for producing the phosphor composition is also disclosed wherein in addition to the sources of calcium and tungstate in a Ca:W ratio of about 1 and a lead source there is added extremely finely divided silicon dioxide to form a relatively uniform admixture that is thereafter milled to a particular particle size and heated under controlled temperature conditions for a time sufficient to produce the luminescent phosphor composition. Additionally, an improved lamp utilizing a silica modified lead activated calcium tungstate phosphor is disclosed.
Inventors
- 👤 F Shaffer
Bibliographic Details
Claims Analysis
Total Claims: 2References Cited (Backward Citations)
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