A cathode ray tube in the color of the type a positioning of the beam and more particularly such a tube in which at least one of the strips of phosphor red, blue and green, has a width different to those of the

摘要

Described is a beam index type color cathode ray tube in which at least one of tricolor phosphor stripes, that is the red, blue and green stripes, is different in width from the other color phosphor stripes, and m index stripes are associated with n sets or triplets of the color phosphor stripes. The widthwise center-to-center distance between the adjoining color phosphor stripes is set to a constant value. Each index stripe is of a width lesser than the width of the guard band provided between adjoining ones of the color phosphor stripes, and is provided at the widthwise center of the associated guard band. The arrangement provides index signals of sufficient intensity, while assuring a positive color switching.