Prevention of Static Discharge in Display Tubes
Original Publication Date: 1978-May-01
Included in the Prior Art Database: 2005-Feb-21
Fig. 1 schematically illustrates how static electricity built up on face plate 1 of cathode ray tube 2 can cause two undesirable effects. Firstly, an operator may sense the accumulated charge if he touches face plate 1. Secondly, the accumulated charge can cause dust to be attracted to face plate 1, giving a degradation of the picture quality. These effects can be avoided by providing a separate discharge path for the charge. This could be done by providing a grounded safety plate which is either inherently conductive, or has a conductive layer provided thereon (for example, a layer of sputtered or evaporated tin oxide). However both these methods call for extra expense in that either more expensive conductive material must be used for the safety plate or an additional conductive layer must be provided.