Fluorescent lamp with zinc silicate phosphor and protective phosphor layer
AssigneeGeneral Electric Company
InventorsJianmin HE, Jon Bennett JANSMA, William Erwin COHEN
Life of this patent
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Abstract
A fluorescent lamp comprises a glass envelope that is light transmitting. Also included is means for providing a discharge inside the envelope. A discharge-sustaining fill includes mercury and an inert gas sealed inside the envelope. An underlying phosphor-containing layer is disposed inside the envelope. The underlying layer includes zinc silicate phosphor. A protective phosphor-containing layer is disposed over the underlying layer at a location that is more distal from the glass than the underlying layer. A ratio of a surface density of the protective layer to a surface density of the underlying layer is at least 0.4:1.
Claims31
A fluorescent lamp comprising:
- a glass envelope that is light transmitting;
- means for providing a discharge inside said envelope;
- a discharge-sustaining fill of mercury and an inert gas sealed inside said envelope;
- an underlying phosphor-containing layer disposed inside said envelope, said underlying layer comprising zinc silicate phosphor;
- and
- a protective phosphor-containing layer disposed over said underlying layer at a location that is more distal from said glass than said underlying layer;
- wherein a ratio of a surface density of said protective layer to a surface density of said underlying layer is at least 0.4:1.
A fluorescent lamp comprising:
- a glass envelope that is light transmitting;
- electrodes spaced apart inside said envelope for providing a discharge inside said envelope;
- a discharge-sustaining fill sealed inside said envelope;
- an underlying phosphor-containing layer disposed inside said envelope, said underlying layer comprising zinc silicate phosphor;
- and
- a protective phosphor-containing layer disposed as a separate coating over said underlying layer at a location that is more distal from said glass than said underlying layer, wherein said protective phosphor-containing layer does not include zinc silicate phosphor.
Dependencies are inferred from the claim text.