A magnetic deflection up-date: field equations, CRT geometry, the distortions and their corrections

The evolution of the magnetic deflection yoke to wide angles and high performance, and the modification of cathode-ray-tube (CRT) structures has responded to ever-more-demanding performance in diverse applications. This article probes the past to extract those basics by which precise deflection performance of CRT systems may be calculated. Development of beam-patch plots from a yoke´s magnetic-field plot leads to a simplified equivalent constant-strength field. The characteristics of yoke behavior are established. An ideal yoke configuration, which does not distort the electron beam´s focused spot, is identified. Its angular deflection is proportional to field strength; response is linear. A unified treatment of diverse CRT geometries provides precise deflection equations. Geometric distortion components are identified, their equations developed, and correction methods described