| 摘要 |
An electron gun for a television cathode ray tube is disclosed having cathode means and grid means for producing a beam of electrons. A low-aberration, low-magnification main focus lens means comprising at least three electrodes receives a predetermined pattern of applied voltages to establish a single, continuous electrostatic field having an axial potential distribution which, at all times during tube operation, decreases smoothly and monotonically from a relatively intermediate axial potential to a relatively low-intermediate axial potential spatially located at a lens intermediate position. The axial potential then increases smoothly, directly and monotonically from the relatively low intermediate axial potential to a relatively high axial potential. The gun is characterized by the synthesizing of the relatively low-intermediate axial potential by electrode means comprising a composite electrode made up of an odd-number plurality of apertured elements separated by gaps. The even-numbered ones of the elements have the relatively intermediate applied voltage thereon, and the odd-numbered ones of the elements have a relatively low applied voltage thereon. The spacing of the elements of the composite electrode, and the number of the elements, the aperture size and configurations of the elements, and the periodic applied voltages thereon are such as to produce the relatively low-intermediate axial potential in non-periodic form at the lens intermediate position.
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