| 摘要 |
A pair of ring-shaped magnets, or magnetic pole pieces, having the same magnetic field strength, or magnetic flux density, are disposed about the neck portion of a cathode ray tube (CRT) for statically converging a plurality of inline electron beams on the CRT's faceplate. The magnetic ring pair includes an inlet ring magnet facing the CRT's base and an outlet ring magnet facing the CRT's faceplate, with the inlet ring magnet having a thickness greater than that of the outlet ring magnet along the CRT's longitudinal axis. The inlet ring magnet thus exerts a larger off-axis force on the electron beam than the outlet ring magnet because of the longer beam path in the inlet ring magnet to permit the magnetic ring pair to apply a maximum convergence correction for substantially misconverged electron beams and a minimum convergence correction when the beams are in convergence. The pair of ring magnets may also be used in a color purity magnet assembly to adjust electron beam convergence to provide a high degree of color purity.
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