Abstract: A cathode ray tube for multimedia includes a shadow mask having a plurality of beam-guide apertures. Each of the beam-guide apertures has a stripe shape and the ratio of a horizontal length of an effective screen to a horizontal pitch of the beam-guide apertures in the center of the shadow mask is in the range of 1:8.81×10−4 to 1:1.23×10−3. The ratio of the horizontal pitch of the beam-guide apertures in the center of the shadow mask to the thickness of the shadow mask is in the range of 1:0.25 to 1:0.56.

Abstract: A faceplate panel for a cathode ray tube includes an exterior surface having a substantially flat shape, and an interior surface having a concave shape. The interior surface curves in a direction toward the flat exterior surface with a curvature radius R.sub.p satisfying the following condition:1.2R.ltoreq.R.sub.p .ltoreq.8R,where R=1.767.times.the diagonal length of the effective screen of the panel. Furthermore, a peripheral thickness t of the faceplate panel at the diagonal end of the effective screen satisfies the following condition:B.ltoreq.t.ltoreq.A,where B is the peripheral thickness of the panel at the diagonal end of the effective screen when a curvature radius R.sub.p of the interior surface is 8R, and A is the peripheral thickness of the panel on the diagonal end of the effective screen when a ratio of the light transmission at the peripheral portion of the diagonal end of the effective screen to the light transmission at the central portion of the effective screen is 0.85.

Abstract: A non-causal error diffusion technique that is capable of gray image signals into binary image signals to prevent the occurrence of visible correlated patterns and/or artifacts. In the non-causal error diffusion method, transformation errors produced when great gray level sets of image signals for a certain pixel are transformed into reduced gray level sets of image signals are reflected to the image signals for pixels at non-causal locations with respect to the certain pixel.