EM screening device for CRT display screen or monitor - screens low frequency fields using a demagnetising coil with screening plate surrounding tube periphery

摘要

A cathode ray tube (2) has a demagnetising coil (3) located around the screen section periphery and this is enclosed by a rectangular section masking frame (1) supported on a unit (2a) fixed to the tube. Also located within the masking frame is a screening plate (4) that is produced of metal. This is produced as a metal pressing with a main `L' shaped cross section that surrounds the tube. Projecting lugs are formed at the corners for fixing to the mask housing. ADVANTAGE - Simplified assembly. Eliminates use of copper spring and conductive layer.