Patent ID: 7741620

Claim:
A multibeam modulator which generates a plurality of individual beams from a particle beam, the particle beam illuminating said multibeam modulator at least partially over a surface thereof, said multibeam modulator comprising: a plurality of openings having equal size, each opening being arranged in a cell of a matrix of m×n cells; wherein the matrix comprises: a number m of matrix columns, each with a number n of cells; and a number n of matrix rows, each with a number m of cells and a number k of openings; wherein a size of each cell of the matrix is equal to the size of one of the openings, such that each opening occupies the entire cell in which each opening is arranged; wherein all of the openings in each matrix row form an aperture row within a limited portion of each matrix row, such that a number of cells of each aperture row is less than the number m of cells of each matrix row; wherein the density of the k openings within each matrix row is inhomogeneously distributed; and wherein a distance between the k openings of a single matrix row is equal to an integer multiple of the size of one of the cells.