引言众所周知,在一列式彩色CRT中使用了自会聚系统,其偏转线圈引起了很大的象散,这种象散大大减弱了屏边缘的分辨率。近来,做了一些尝试以校正这种象散,即在电子枪中使用一种具有双电位主透镜系统的聚焦电极的四极透镜。在四极透镜上加上一个与束偏转同步的动态电压,以补偿由于偏转系统引起的象散。这种动态电压也可以在整个屏上使电子束聚焦,即能够实现动态聚焦。 INTRODUCTION It is well known that self-convergence systems are used in an in-line color CRT, which causes great astigmatism in the deflection yoke, which greatly reduces the resolution of the screen edges. Recently, attempts have been made to correct such astigmatism by using a quadrupole lens having a focusing electrode of a bipotential main lens system in an electron gun. A quadrupole lens is added with a dynamic voltage synchronized with beam deflection to compensate for astigmatism due to the deflection system. This dynamic voltage can also focus the electron beam across the entire screen, enabling dynamic focusing.