Visibility evaluation of the inverse-phase CRT raster moire pattern

Reducing moire is an important consideration in CRT design. This paper aims to investigate how the visibility of the inverse-phase raster moire, a typ ical pattern of the raster moire, is influenced by the distribution of the electron beam and the structure of shadow mask apertures. First, a simple m odel based on the luminance distribution on the CRT screen and characterist ics of the human vision was used to calculate the perceived intensity of th e inverse-phase raster moire. This calculation was made to examine the effe ct of model parameters. It showed that the inverse-phase raster moire consi sts of (1,1)-order moire components. It was also found that the perceived i ntensity increases with a decrease in electron beam diameter and with an in crease in horizontal aperture pitch. In addition, a subjective evaluation t est was conducted using an inverse-phase moire pattern reproduced by the im age simulation. Test results agreed with the calculated results. Finally, i t was revealed that when an electron beam shape having a Gauss distribution was used, most of the raster moire is the inverse-phase raster moire cause d by the (1,1)-order component, while the (2,2)-order moire component was v ery low.