Magnetic Field Distribution of Shadow Mask Having L-Shaped Magnetic Material

An effective method of shielding CRTs from environmental magnetic fields is presented. The key to this method is the use of L-shaped strips of iron. The L-shaped pieces are arranged around the frame of the CRT. The new shielding method has the effect of reducing and reshaping the field perpendicular to the screen, and reduces color changes. On the other hand, there are no effects from reducing and reshaping the field parallel to the screen.