| 摘要 |
<p>This disclosure depicts a CRT (color cathode ray tube) of the shadow mask type, and an improved shadow mask therefor. The CRT has a screen and an electron gun assembly for generating a plurality of electron beams. The improved shadow mask has a dished perforate central portion for selectively transmitting electrons to the screen. The mask has a predetermined surface on a peripheral portion of the mask which is so oriented that when the mask is in place in an operating tube there results an undesirable specular electron reflection of overscanned electrons off the exposed surface and a visible electron flooding of the screen near its perimeter. The shadow mask is characterized by having on the said surface an array of close-spaced grooves oriented to scatter a major fraction of reflected overscanned electrons away from the screen and to thereby markedly suppress the said visible electron flooding of said screen.</p> |
