彩色显像管中主聚焦透镜的研究

在COTY系统中,采用XL透镜来改善会聚性能,减小会聚/聚焦之间的矛盾。XL透镜可以在不损失聚焦性能的前提下缩小束间距提高会聚特性。但是在XL透镜中边束像差比中束大得多,为了进一步降低像差,本文提出在XL电子枪中采用OLF透镜来扩大透镜的孔径,改善分辨率。本文给出了三维计算机程序,对主聚焦透镜进行三维计算,得到了球差系数和其它光学参量。这些数据证实了在新的方案中球差确实被降低,而且会聚特性也得以改善。

The Study of the Main Focusing Lens in Colour Picture Tube

In COTY-29 System, XL lens is ultilized to improve the convergence performance,and minimize the convergence/focus contradiction. In XL lens,the convergence error is decreased by reducing beam spacing without deteriorating of focusing performance,however, the aberration of the side beam is much larger than that of centre beam. A new structure of the main lens for reducing the aberration is put forward in this paper. OLF lens is used as main focusing lens in XL electron gun,so that the main lens has been effectively enlarged and the resolution can be improved as well. The 3D computer program for calculating the main lens is given. The spherical aberration coefficient and other optical coefficients are obtained. These coefficients confirm that the spherical aberration in the new structure has been reduced,and the convergence performance has been improved too.