A Trinitron gun with dynamic quadrupole lens (DQL) providing focus control and astigmatism correction

A quadrupole lens system which can be integrated into the Trinitron gun system is proposed. The system´s main feature is that the quadrupole lens is located inside the main lens. The advantages of this system are: the construction is simple, with a single quadrupole lens for three beams, and the quadrupole effect is not affected by the spherical aberration of the main lens. As geometric and astigmatic defocusing is cancelled by applying dynamic focusing, high uniform resolution has been realized over the entire screen.<>