Patent ID: 7025893

Claim:
A method of producing a tin oxide thin film heater, comprising the following steps: (a) providing a substrate having an upper and lower surface, and at least two spaced-apart edges that are parallel to each other; (b) forming on at least a portion of said upper surface of said substrate a thin film layer of tin oxide material having at least two spaced-apart edges that are parallel to said two spaced-apart edges of said substrate; (c) adjacent said two spaced-apart edges of said thin film material, removing tin oxide material to define at least two regions that are parallel to said two spaced-apart edges of the thin film layer in which an underlying region of said upper surface of said substrate is exposed; wherein when electrical power is coupled between said two spaced-apart edges of said thin film layer, heat distribution across said thin film layer is more uniform than if said regions defined at step (c) were absent.