抄録
In many color display tubes, the focus characteristics of the red beam at the right end of the screen and of the blue beam at the left end are not very good. These poor focus characteristics are one of the causes of the degradation in the quality of display monitors. To correct this defocusing (Delta Deflection Defocusing), a new electron gun has been developed. An additional dynamic focus voltage and the new structure of the beam apertures make it possible to give an opposite astigmatism lens effect to the red and blue beams. Therefore, it is possible to give the optimum astigmatism lens effect to all three beams over the entire screen. The newly developed electron gun contained in a 41 cm color display tube, reduced the horizontal spot size of the red beams at the right corners of the screen and of the blue beams at the left corners by up to 10%.
