US Patent 7294248 - Electron emission nanostructure formed using electrophoretic deposition

http://www.freepatentsonline.com/7294248.html

For field emission displays and other devices that employ nanostructures for electron emission there are two methodologies of manufacture - 1) prefabrication of the nanostructure which is used as an emissive coating for electrodes on a substrate or 2) direct fabrication of the nanostructure on the substrate. The first method has several advantages in that the manufacturing process can be performed more cheaply using printing and deposition technologies at lower temperatures than direct fabrication. However, deposited nanostructures have a random orientation that are not optimal for directed field emission. This patent from Xintek, Inc. teaches a method of nanostructure deposition that can form directed field emission nanostructures. Claim 1 reads:

1. A method of forming an electron emitter, the method comprising the steps of: (i) forming a nanostructure-containing material; (ii) forming a mixture comprising nanostructure-containing material and a matrix material; (iii) depositing a layer of the mixture onto at least a portion of at least one surface of a substrate by electrophoretic deposition; (iv) sintering or melting the layer thereby forming a composite; and (v) electrochemically etching the composite to remove matrix material from a surface thereof, thereby exposing nanostructure-containing material.