Cathode ray tube comprising terrestrial magnetism sensors.

摘要

A cathode ray tube apparatus can accurately, easily and automatically correct influences exerted on both of a beam landing drift and an image distortion drift by terrestrial magnetism applied to a cathode ray tube (CRT). A correction current based on an output of a terrestrial magnetism sensor (45) is supplied to a Z-axis correction coil (41) and an X-X axis correction coil (42). A terrestrial magnetism component (BH cos theta ) of Z-axis direction is canceled by a correction magnetic flux generated by the Z-axis correction coil (41), and a terrestrial magnetism component (BH sin theta ) of X-axis direction is canceled by the X-X axis correction coil (42), whereby a beam landing drift and a image distortion drift are corrected automatically. <IMAGE>