Electroluminescent lamp with controlled field intensity for displaying graphics
AssigneeDurel Corporation
InventorJames H. Butt
Life of this patent
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Abstract
An EL lamp includes a transparent electrode, an electroluminescent dielectric layer overlying the transparent electrode, a patterned insulating layer overlies selected portions of the dielectric layer for reducing the electric field across the selected portions of the electroluminescent dielectric layer, and a rear electrode overlying the insulating layer and the electroluminescent dielectric layer. The insulating layer is preferably a low dielectric constant material and can overlie the electroluminescent dielectric layer or can be located between a separate dielectric layer and a phosphor layer. A gray scale is produced by depositing or printing more than one thickness of insulating layer.
Claims8
An electroluminescent lamp capable of producing a graphic image having two brightness levels when illuminated, said lamp comprising:
- a transparent electrode;
- an electroluminescent dielectric layer overlying said transparent electrode;
- a first insulating area overlying a portion of said electroluminescent dielectric layer for reducing the electric field across said portion and for reducing the amount of light emitted by said portion;
- and
- a rear electrode overlying said insulating area and said electroluminescent dielectric layer.
An electroluminescent lamp displaying a predetermined graphics pattern having two brightness levels when lit and having a plain face when not lit, said lamp comprising:
- a transparent electrode;
- an electroluminescent dielectric layer overlying said transparent electrode;
- an insulating area overlying a portion of said electroluminescent dielectric layer, said insulating area having a pattern corresponding to said predetermined graphics pattern to cover said portion of said electroluminescent dielectric layer and to leave a remainder of said electroluminescent dielectric layer exposed;
- said insulating area reducing the electric field across a portion of said electroluminescent dielectric layer and reducing the amount of light emitted by said portion;
- a rear electrode overlying said insulating area and the remainder of said electroluminescent dielectric layer.
An electroluminescent lamp capable of producing a graphic image when illuminated, said lamp comprising:
- a transparent electrode;
- an electroluminescent phosphor layer overlying said transparent electrode;
- a dielectric layer overlying said electroluminescent phosphor layer, said dielectric layer including increased thickness portions for reducing the electric field in selected areas across said electroluminescent phosphor layer;
- and
- a rear electrode overlying said dielectric layer.
An electroluminescent lamp capable of producing a graphic image when illuminated, said lamp comprising:
- a transparent electrode;
- an electroluminescent phosphor layer overlying said transparent electrode;
- a plurality of insulating areas overlying said electroluminescent phosphor layer in a pattern corresponding to said graphic image for reducing the electric field across a portion of said electroluminescent dielectric layer;
- a dielectric layer overlying said electroluminescent phosphor layer and said insulating areas;
- and
- a rear electrode overlying said dielectric layer.
Dependencies are inferred from the claim text.