Dan J Haflinger

US Patent:

40328155, Jun 28, 1977

Filed:

Nov 4, 1975

Appl. No.:

5/628805

Inventors:

Dan Joseph Haflinger - Rancho Santa Fe CA

Assignee:

Stromberg Datagraphix Inc. - San Diego CA

International Classification:

H01J 2946
H01J 2956

US Classification:

315 14

Abstract:

An electron gun system is described for generating a high current collimated beam of electrons for use in a shaped beam cathode ray tube system. The electron gun includes a cathode having an electron emitting surface for generating free electrons, a collimating grid axially spaced from the cathode and having a central aperture, and a control grid axially spaced from the collimating grid and having a central aperture axially aligned with the aperture of the collimating grid. The control grid receives a varying potential for establishing an electric field which is substantially axial over at least a central portion of the electron beam so as to collimate the beam axially. The collimating grid receives a fixed potential relative to the cathode and influences the electric field near the collimating grid and near the outer perimeter of the electron beam so as to form centrally directed field components for directing electrons in the outer portion of the beam toward the central portion of the beam to compensate for space charge effects and to maintain the collimation of the electron beam.