Electron beam apparatus having an electron lens and a structure for compensating for a spherical aberration of the electron lens

摘要

In a cold cathode electron beam device, groups of electron emission cones emit electrons which are extracted from the cones by respective extraction electrodes. The emitted electrons are focussed into a beam by an electron lens so as to strike a fluorescent screen. In order to minimize the size of the beam spot where the beam strikes the screen, a structure is included which compensates for a spherical aberration property which is inherent to the electron lens. The spherical aberration is compensated for by placing a focus electrode for each group of electron emission cones on a common substrate along with the extraction electrode, such that the focus electrode surrounds the extraction electrode.