Visibility Evaluation of the Inverse-Phase CRT Raster Moire Pattern

Naoki SHIRAMATSU  Shuji IWATA  Takumi MINEMOTO  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E83-C   No.10   pp.1594-1601
Publication Date: 2000/10/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Electronic Displays)
Category: 
Keyword: 
cathode ray tube,  moire pattern,  electron beam,  shadow mask,  image simulation,  

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Summary: 
Reducing moire is an important consideration in CRT design. This paper aims to investigate how the visibility of the inverse-phase raster moire, a typical pattern of the raster moire, is influenced by the distribution of the electron beam and the structure of shadow mask apertures. First, a simple model based on the luminance distribution on the CRT screen and characteristics of the human vision was used to calculate the perceived intensity of the inverse-phase raster moire. This calculation was made to examine the effect of model parameters. It showed that the inverse-phase raster moire consists of (1,1)-order moire components. It was also found that the perceived intensity increases with a decrease in electron beam diameter and with an increase in horizontal aperture pitch. In addition, a subjective evaluation test was conducted using an inverse-phase moire pattern reproduced by the image simulation. Test results agreed with the calculated results. Finally, it 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 caused by the (1,1)-order component, while the (2,2)-order moire component was very low.