Electroluminescent phosphor with plural moisture resistant coatings thereon
A moisture-resistant electroluminescent phosphor is provided wherein the individual phosphor particles have a first coating of an inorganic moisture-resistant coating and a second coating of an organic moisture-resistant coating. The process for making the moisture-resistant phosphor comprises applying a first layer of an inorganic moisture-resistant coating to individual particles of an electroluminescent phosphor to form a first-coated phosphor, substantially isolating said first-coated phosphor from contact with atmospheric oxygen and moisture, and applying a second layer of an organic moisture-resistant coating to the first-coated phosphor to form a second-coated phosphor.
1. An electroluminescent phosphor particle having thereon a first layer of an aluminum nitride and a second layer of an organic material.
2. The phosphor of claim 1 wherein said electroluminescent phosphor comprises zinc sulfide activated with one or more activators.
3. The phosphor of claim 1 wherein said organic material is substantially transmissive of visible light, electrically insulating, and has low moisture permeability.
4. The phosphor of claim 1 wherein the second layer is a parylene, polyester, polyalkylacrylate, or vinyl-epoxy resin.
5. The phosphor of claim 1 wherein the second layer is a parylene.
6. The phosphor of claim 1 wherein the second layer is poly(p-xylylene) or poly(p-α-xylylene) with α=H, Cl, Br, F, alkyl or amino.