| 摘要 |
<p>BOX-SHAPED SCAN EXPANSION LENS FOR CATHODE RAY TUBE A cathode ray tube is provided with a rectangular box-shaped lens intermediate the tube's screen and beam deflection plates for amplifying beam deflections in both of the horizontal and vertical axes. In one form, useful in either monoaccelerator or PDA tubes, the lens includes four tubular elements disposed end-to-end and spaced apart a sufficient distance to isolate them electrically. The adjacent ends of each pair of the elements are oppositely curved to provide electron lenses having vertical cylindrical mid-surfaces. The radii of the cylindrical surfaces and the voltages applied to each element are adjusted to provide a lens system that produces minimum distortion and optimum linearity in the resultant display.</p> |
