Patent ID: 6891340

Claim:
A picture tube ( 1 ) comprising a screen ( 2 ) with a plurality of interspersed sets of parallel strips ( 5 a, 5 b, 5 c ) of light-emitting material, each set emitting light of a specific color when hit by electrons, a plurality of electron guns ( 4 ), each adapted to generate an electron beam ( 9 ) associated with the strips in one of said sets of strips, a deflection unit ( 10 ) for deflecting each electron beam onto one of the strips in the corresponding set of strips, thereby exciting this strip to emit light, and at least one pair of comb-shaped electron-detecting means ( 12 , 13 ) having a plurality of interdigitated finger portions ( 14 , 15 ) extending parallel with the strips ( 5 ), for generating a signal ( 18 ) relative to the position of an electron beam ( 9 ) with respect to the strips ( 5 ), characterized in that the deflection unit ( 10 ) is arranged to deflect the beams onto selected strips ( 22 r, 22 g, 22 b ) having coincident sides which neighbour finger portions ( 14 , 15 ) of the same detecting means ( 12 , 13 ), said selected strips ( 22 r, 22 g, 22 b ),excited by the electron beams, being separated by at least one unexcited strip, respectively.