Multi-layer common lens arrangement for main focus lens of multi-beam electron gun

摘要

An inline electron gun for use in a multi-beam electron gun as in a color cathode ray tube (CRT) includes a main focus lens for focusing the electron beams on the CRT's display screen for providing a video image. The main focus lens includes plural charged grids aligned in a spaced manner along the electron gun's longitudinal axis through which plural (typically three) electron beams are directed. One or more of these charged grids includes at least two aligned common apertures for passing the three electron beams. The layered common aperture arrangement allows for increasing the length of the electron gun as well as the effective diameter of the electron gun's main focus lens for improved video image resolution without introducing electron beam astigmatism.