Abstract: A cathode ray tube is disclosed which has a modulating grid for varying the charged particle flux density along a cross-section of a flat thin of charged particles or for varying the charged particle flux density in each of a plurality of charged particle beams arranged side-by-side in a sheaf. In a preferred embodiment, a cathode ray tube according to the invention includes a modulating grid and associated electronics that permit the tube to project a single line of video information simultaneously, thus increasing picture brightness. The beam scan is solely vertical, rather than horizontal and vertical, as in cathode ray tubes of the prior art.