Spatial Frequency Analysis of CRT Beam Profile and Design of Electron Gun for Reducing Moire Fringes

Abstract

In order to reduce raster moire fringes appearing on color CRTs, electron beam profiles were investigated. By analyzing the beam profile in the spectral frequency domain, the contrast of the combined moire patterns of modes(1, 1)and(2, 2)was found to become proportional to the spectral intensity, 2/S, of the beam profile, where S is the scan line pitch. As a result of examining relationships between C-G1 electrode separation of an A-EA-MDF electron gun and spectral intensity, it became clear that the spectral intensity at 2/S decreases with larger electrode separation. Moire fringes can be reduced without deteriorating the resolution when C-G1 separation is 90 μm.