Background Color for Display
Original Publication Date: 1978-May-01
Included in the Prior Art Database: 2005-Feb-21
Background color is added to a monochrome alphanumeric display by use of a multicolor penetration tube. One of the available colors is selected for the alphanumeric display in the usual manner. During the vertical retrace interval, however, a second low resolution raster is added and the anode voltage of the tube changed, so that the depth of penetration of the electrons into the phosphor layers is varied and a different color produced as background to the displayed information. By defocussing or impressing a spot wobble on the electron beam during the second raster scan time a `broad-brush' background color effect is achieved.