Cathode-ray-tube television type display device - is used with variable frame and line frequencies for high resolution static pictures

摘要

The purpose of the method is to display static pictures with a greater number of lines and lower frame frequency than normal television pictures to improve the resolution. The CRT is made up with two or more phosphors on the screen, each having a different afterglow period. Two phosphors may be arranged in horizontal stripes in a shadow-mask CRT with two electron guns. The line scan is arranged such that by means of one gun and the shadow mask one phosphor is excited while the second gun will excite the other phosphor. The afterglows may be less than 1, and 10 to 1000 milliseconds respectively. When dynamic pictures are to be displayed every other line of the short afterglow phosphor is excited while every line of the long afterglow phosphor is used with static pictures. The composite video signal contains the control signals in the video signal bandwidth.