Patent ID: 7823224

Claim:
A mask comprising: a frame, where the frame has a first support with a first end of a strap attached thereto, where the strap has a second end which incorporates a first field emission structure, where the frame has a second support which incorporates a second field emission structure, where the second end of the strap is attached to the second support of the frame when the first and second field emission structures are located next to one another and have a certain alignment with respect to one another, where each of said first and second field emission structures comprise an array of field emission sources each having positions and polarities relating to a spatial force function that corresponds to a relative alignment of the first and second field emission structures within a field domain, said spatial force function being in accordance with a code, said code corresponding to a code modulo of said first field emission structure and a complementary code modulo of said second field emission structure, said code defining a peak spatial force corresponding to substantial alignment of said code modulo of said first field emission structure with said complementary code modulo of said second field emission structure, said code also defining a plurality of off peak spatial forces corresponding to a plurality of different misalignments of said code modulo of said first field emission structure and said complementary code modulo of said second field emission structure, each of said plurality of off peak spatial forces being less than half of said peak spatial force.