Crt Having a Low Moire Transformation Function

A display device comprising:

• envelope having a panel and funnel
• said panel including a faceplate portion, said faceplate portion having a luminescent screen, said screen having a plurality of phosphor elements, each of said phosphor elements forming substantially a column,
• said panel further including a mask contained therein, said mask having apertures which form substantially straight aperture columns, each of said apertures corresponding to a respective phosphor element, said apertures in each of said aperture column being separated by unetched metal, said apertures in said aperture columns having an aperture pitch;
• said funnel having a neck at an end opposite of said panel, said neck containing therein an electron gun;
• said gun emitting at least one electron beam which scans across said aperture columns, portions of said electron beam propagate through said apertures and impinge corresponding said phosphor elements, said electron beam scanning across said screen in a number of sweeps, said number of sweeps making up-a full screen image being a scan line mode, wherein spacially adjacent sweeps each have a scan line spacing, said electron beam having a spot size, said spot size being a dimension of said electron beam at 5% of the peak electron beam intensity, said dimension being parallel to said aperture columns, said spot size to said pitch having a ratio exceeding a value of about 0.9 along at least two of said sweeps.

The CRT having envelop including a panel attached to a funnel, said funnel having a neck and an electron gun for generating at least one electron beams contained in said neck, and a mask contained in said envelop near said panel, comprising:

• a region in said mask having columns of apertures of predetermined heights and predetermined pitches;
• and
• said at least one electron beam having a spot size range and spot shape selected such that the moiré transformation function for said CRT in said region is less than about 0.02, wherein, said moiré transformation function being a quotient having a numerator being the difference between a maximum value and a minimum value of mask transmission and a denominator being the sum of said maximum and said minimum values;
• wherein
• mask transmission is the percentage of electrons of a uniform electron beam incident on said that can propagate therethrough said apertures averaged over a plurality of adjacent said mask aperture columns and said regions containing said maximum and minimum values are adjacent to each other.