Patent ID: 6420841
Filing Date: 2002-07-16
Classification: H01J

Abstract:
A colour display device (19) provided with a colour display tube (1) having a display window (3), an electron gun (6) and a deflection unit (11), which electron gun (6) comprises cathodes (20), a beam-forming section (21,22), a focusing electrode (23) and a final electrode (24), viewed in the direction from the electron gun (6) to the display window (3), to which voltages are applied during operation, said electron gun (6) generating electron beams (7,8,9), during operation, that are deflected by the deflection unit (11) to scan the display window (3) in lines so as to form a picture, the colour display device (19) further comprising electronic means (14) generating a video signal at a pixel frequency, characterized in that the voltage on the focusing electrode (23) is varied as a function of the voltages on the cathodes (20).