Compositions and methods for modifying lumen maintenance characteristics of phosphor-containing coatings
View Patent ↗Phosphor-containing coating compositions and methods capable of changing the lumen maintenance characteristics of phosphor-containing coatings and fluorescent lamps that utilize such coatings. Lumen maintenance of a fluorescent lamp can be modified by forming a phosphor-containing coating to contain at least a first phosphor that depreciates during operation of the fluorescent lamp, and forming the phosphor-containing coating to further contain an additive composition in a sufficient amount and sufficiently uniformly distributed in the phosphor-containing coating to inhibit depreciation of the first phosphor during operation of the fluorescent lamp.
1. A method for improving the lumen maintenance of a fluorescent lamp, the method comprising:
providing a phosphor blend containing a first phosphor that exhibits a poorer lumen maintenance than at least a second phosphor in the phosphor blend; and
forming with the phosphor blend a phosphor-containing coating of a fluorescent lamp, wherein the phosphor-containing coating contains an additive composition in a sufficient amount and sufficiently uniformly distributed to improve the lumen maintenance of the first phosphor;
wherein the forming step comprises:
combining the phosphor blend with a liquid vehicle that contains at least one soluble salt of the additive composition; and
converting the soluble salt to the additive composition.
2. The method of claim 1 , wherein the additive composition is yttria and/or lanthana.
3. The method of claim 1 , wherein the forming step causes the additive composition to define a uniform coating over and surrounding individual particles of the first phosphor.
4. A method for improving the lumen maintenance of a fluorescent lamp, the method comprising:
forming a phosphor-containing coating to contain at least a first phosphor that depreciates during operation of the fluorescent lamp; and
forming the phosphor-containing coating to further contain an additive composition in a sufficient amount and sufficiently uniformly distributed in the phosphor-containing coating to inhibit depreciation of the first phosphor during operation of the fluorescent lamp;
wherein the step of forming the phosphor-containing coating to further contain an additive composition comprises:
combining a phosphor blend with a liquid vehicle that contains at least one soluble salt of the additive composition; and
converting the soluble salt to the additive composition.
5. The method of claim 4 , wherein the additive composition is yttria and/or lanthana.