Talk:Shadow mask
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[edit] Types of shadow masks
The dot triad type has an individual hole for every red, green and blue phosphor dot.
A later development used square or rectangular holes, each masking a vertical section of a trio of red, green and blue stripes. This design allowed for the enhanced brightness of the Trinitron design while eliminating the spacing wires and avoiding infringement on the Trinitron patent even though the three electron beams were arranged in a horizontal line like the Trinitron, instead of a triad like the earlier type. This type also allowed the more conventional spherical profile front instead of the costlier cylindrical shape used by the Trinitron.
After the grid mask (I don't know what any manufacturer called it) was first used in the 1980's (large numbers used in arcade videogames), few CRT televisions have used the older dot triad style due to the higher brightness possible at lower electron beam power with the grid mask.
Truly flat CRT displays are manufactured by heating and stretching the aperture grille or shadow mask then forming a frame (usually glass) around the edges. Tension is held until the frame material cools or sets. The grill or mask and frame is then bonded between the front glass and rear shell of the tube.
This design eliminates any distortions due to its own heat since the grille or mask is heated to a higher temperature during manufacture than it will ever reach in normal operation.
Just some more random info for someone to tuck into the article if they care to research and format it into something readable.