Importance

Loading Importance Indicators...

Abstract

A multiple color imaging device such as a beam index CRT (FIG. 3a/b), with red, green and blue phosphor stripes arranged in triplets each defining one color image pixel in the line scan direction having at least the red and green phosphor stripes coated with an electrically insulating barrier layer 38 on which is formed a thin layer 39 of blue emitting phosphor. In color display mode the beam energy is sufficient to penetrate the barrier layer and excite the principal stripe phosphor to give the desired color emission but also excites the blue phosphor, blue emissions being perceived at lower luminance than the red and not detrimental to perceived color purity. In monochrome mode the beam energy is reduced to excite only the blue phosphor. As each stripe is able to emit blue when excited the image resolution for monochrome is increased from color triplet dimensions to individual stripe dimensions or better. The low level of blue emissions is suitable, and preferred, for night viewing of FLIR images, particularly with night vision goggles. Individual phosphor grains may be given a skin of the monochrome phosphor (FIG. 4) or it may be mixed with the principal phosphor without a barrier but with a red/green filter in front of the screen for monochrome operation (FIG. 2).

Loading the Abstract Image...

First Claim