Complex lens trinitron gun for a high-resolution color tube

19V″ Cathode Ray Tubes (CRT) with phosphor pitch of 0.31 mm and neck diameter of 36.5 mm have been installed in graphic display monitors with the 1280×1024 pixel format. However, to meet user demand for greater compactness, a new Trinitron gun has been developed for 16V″ high resolution CRT with neck diameter of 30.6 mm. A combination of small caliber bi-potential and large caliber Trinitron lenses, complex lens structure, is employed for the new gun in order to obtain the same resolution as the current on 16V″ CRT with 30.6 mm diameter. The spherical aberration coefficient has successfully been reduced by half with optimum gun structures calculated by the finite element method (FEM). As a result, this gun's spot size at screen center is now as small as that of the conventional Trinitron gun for 36.5 mm neck. The spot size at the screen corner is also well-focused by dynamic focus and well-formed by dynamic electrical magnetic quadrupole.