Color picture tube with rectangular hall shadow mask

Claim 1

A color cathode-ray tube comprising a shadow mask, an electron gun for producing three electron beams aligned on a straight line for convergence on said shadow mask, and a display screen comprising rectangular luminescent dots, said shadow mask having a pluraliTy of orderly arranged rectangular holes formed therein in a plurality of rows and columns, said holes being spaced by a distance a in each of said rows, and by a distance b in each of said columns, the ratio b/a being larger than 0.34 but smaller than 15, said rectangular holes in every other of said rows being offset with respect to the holes in an adjacent row so that all adjacent rectangular dots on said display screen luminesce differently in color when struck by the electron beam from said electron gun passing through said shadow mask rectangular holes; each of said rectangular holes having a wide side dimension of less than b and a narrow side dimension of less than a/3; said wide side being perpendicular to the direction on which said three electron beams are aligned.