Aluminum nitride passivated phosphors for electroluminescent displays
AssigneeIfire IP Corporation
InventorGuo Liu
Life of this patent
Estimating the term…
Abstract
A novel structure is provided to improve the luminance and operating stability of phosphors used in ac thick film dielectric electroluminescent displays. The novel structure comprises aluminum nitride barrier layers in contact with the phosphor films to prevent phosphor degradation due to reaction with oxygen. The barrier layers can be deposited using vacuum deposition processes that are compatible with the processes used to deposit and anneal the phosphor films. The invention is particularly applicable to phosphors used in electroluminescent displays that employ thick dielectric layers subject to high processing temperatures to form and activate the phosphor films.
Claims31
An improved phosphor film for a thick film dielectric electroluminescent display, said phosphor film selected from the group consisting of:
- (a) a rare earth activated barium thioaluminate;
- (b) a rare earth activated fine grained zinc sulfide;
- (c) a transition metal activated zinc sulfide;
- (d) a rare earth or transition metal activated zinc selenide;
- and
- (e) a rare earth or transition metal activated zinc sulfo-selenide,
- wherein said phosphor film of (a), (b) (d) and (e) is provided with an aluminum nitride barrier layer on a top and/or bottom side of the phosphor film and wherein said phosphor film of (c) is provided with an aluminum nitride barrier layer on the top side of said phosphor film, said aluminum nitride barrier layer improving the stability of the interface between the phosphor film and the display.
A phosphor laminate for use in a thick film dielectric electroluminescent display, said phosphor laminate comprising;
- a phosphor thin film layer selected from the group consisting of
- (a) a rare earth activated barium thioaluminate;
- (b) a rare earth activated fine grained zinc sulfide;
- (c) a transition metal activated zinc sulfide;
- (d) a rare earth or transition metal activated zinc selenide;
- and
- (e) a rare earth or transition metal activated zinc sulfo-selenide, and
- an aluminum nitride layer provided directly adjacent a top and/or bottom side of the phosphor layer of (a), (b) (d) and (e) and wherein said aluminum nitride layer is provided directly adjacent a top side of said phosphor layer of (c).
A thick film dielectric electroluminescent device constructed on a glass or glass ceramic substrate and comprising a phosphor selected from the group consisting of;
- (a) a rare earth activated barium thioaluminate;
- (b) a rare earth activated fine grained zinc sulfide;
- (c) a transition metal activated zinc sulfide;
- (d) a rare earth or transition metal activated zinc selenide;
- and
- (e) a rare earth or transition metal activated zinc sulfo-selenide,
- wherein said phosphor film of (a), (b) (d) and (e) is provided with an aluminum nitride barrier layer on a top and/or bottom side of the phosphor film and wherein said phosphor film of (c) is provided with an aluminum nitride barrier layer on the top side of said phosphor film, said aluminum nitride barrier layer improving the stability of the interface between the phosphor film and the device.
A method for making a stabilized phosphor laminate for use in a thick film dielectric electroluminescent device, said method comprising;
- i) deposition of a phosphor selected from the group consisting of:
- (a) a rare earth activated barium thioaluminate;
- (b) a rare earth activated fine grained zinc sulfide;
- (c) a transition metal activated zinc sulfide;
- (d) a rare earth or transition metal activated zinc selenide;
- and
- (e) a rare earth or transition metal activated zinc sulfo-selenide,
- onto a glass or glass ceramic substrate incorporating a first set of address lines and a dielectric layer;
- iii) deposition of a layer of aluminum nitride on top of said phosphor film of (a)-(e);
- and
- ii) annealing said phosphor film at a temperature of up to about 1100° C.
Dependencies are inferred from the claim text.