IMAGE DISPLAY TUBE HAVING A CHANNEL PLATE ELECTRON MULTIPLIER

摘要

The image contrast in an image display tube having a channel plate electron multiplier can be improved by preventing secondary electrons created on the outer face of the input dynode of a stack of discrete apertured dynodes from entering channels located at a relatively large distance from their origin. This is done by disposing a grid at a short distance from the input dynode. If the grid is held at a positive voltage relative to the input dynode then stray secondary electrons will be attracted towards the grid. Alternatively by the grid being at a negative voltage relative to that of the input dynode then substantially all the secondary electrons will be induced to enter channels close to their origin thus contributing to the overall brightness of the image. Either way the image viewed is spatially correct.