Patent ID: 8791424

Claim:
A control grid for an electron beam generating device comprising: a plurality of hexagonal-shaped apertures arranged in rows and columns, each row extending parallel to a longitudinal axis of the control grid, each column extending orthogonal to the longitudinal axis of the control grid, each of the hexagonal-shaped apertures possessing a width extending parallel to the longitudinal axis of the control grid and a height extending orthogonal to the longitudinal axis of the control grid; and a majority of the hexagonal-shaped apertures in each individual row possess the same height and the same width, the height of at least some of the hexagonal-shaped apertures in a first one of the rows differs from the height of at least some of the hexagonal-shaped apertures in a second one of the rows, and the width of at least some of the hexagonal-shaped apertures in the first one of the rows is the same as the width of at least some of the hexagonal-shaped apertures in the second one of the rows.