Patent ID: 7122223

Claim:
Process for the vacuum treatment of any curved substrate having a circular contour with a given diameter (D 1 ), comprising the steps of: depositing a layer of material coming from a given source of material ( 13 ) on the curved substrate ( 10 ), while interposing a mask ( 19 ) between the curved substrate ( 10 ) and the source of material ( 13 ) at a certain distance from the curved substrate ( 10 ) and approximately parallel to the curved substrate, the mask being stationary with respect to the curved substrate ( 10 ), and selecting the mask to have an annular part ( 20 ) with a diameter (D 2 ) between one quarter and twice the given diameter (D 1 ) of the curved substrate ( 10 ); wherein the certain distance is at least one tenth of, but less than twice, the diameter (D 1 ).