In a color cathode ray tube having a display screen assembled of a plurality of triplets of green, red and blue strips, the distance between the centers of two adjacent strips belonging to the same triplet is at either side of the red strip at least 5% larger than the distance between the centers of two adjacent strips of which one belongs to the triplet and the other belongs to an adjacent triplet.
Color television display tube of the shadow mask type with phosphor lines. In connection with the unequal center distances between the central electron spot and the two outermost electron spots of a triplet as a result of the properties of the deflection coils, the width of the phosphor lines is chosen to be so that the electron spots in the case of mislanding simultaneously cross the edge of the phosphor lines. As a result of this the "white-remains-white" effect is obtained. The intermediate spaces between the phosphor lines of a triplet are preferably equal, which facilitates the inspection of the screens during the manufacture.
A color reference CRT of the type employing a screen of a pattern of individual phosphor elements of different color components, is produced by adjusting the screen weights of the different color components to achieve the desired reference color when the screen is scanned by an electron beam of predetermined beam current and anode potential.
