Effects of Screen Tolerances on Operating Characteristics of Aperture-Mask Trn-Color Klinescopes

The two basic requirements for proper operation of the aperture-mask tri-color kinescope are that the deflection center and the color center of each of the three beams be coincident, and that the beams converge to a point at the aperture mask. Dimensional deviations which occur in manufacture are discussed in terms of variations from the condition of coincident deflection and color centers. The effects of manufacturing variations in the placement of the aperture array and phosphor arrays relative to each other are divided into two general types: the displacement of an array or part of an array within its plane, and the displacement perpendicular to the plane of an array. If the displacement within a plane is uniform in magnitude and direction, a uniform shift of the position of the color centers within the color plane results. If the displacement is not uniform or contains a rotational component, each section of the screen has a unique color center resulting in a confused or enlarged color center for the entire screen. With the second type, the displacements normal to the plane of the array, uniform stretching or contraction of either array can be included because these variations in dimensions cause the color centers to be displaced normal to the plane of the screen. Complete compensation can be made in the finished tube for those manufacturing variations which affect only the position of the color centers.