METHOD OF PREPARING THE SCREEN OF A COLOUR TELEVISION PICTURE TUBE AND DEVICE PERFORMING THE METHOD

摘要

A method of preparing the screen of a colour television image pickup tube by photographic printing which consists in disposing a prism tapered to a prescribed angle between a screen being prepared and a source of light so fixed as to face the screen and projecting light on the screen while causing the prism to revolve, thereby forming on the screen light-exposed portions having a smaller area than the light-permeable portions of a shadow mask and a device for performing the method.