纯平荫罩振动固有频率的研究

在高清晰度电视(HDTV)用的纯平彩色显像管中，由于荫罩的振动从而导致图像色纯度的降低．首先讨论了纯平荫罩振动的固有频率各种分析方法，然后应用弹性力学的基本理论，在建立薄膜横向振动基本方程的基础上，分析了纯平荫罩在四边简支条件下振动的固有频率和振型问题，得出了纯平荫罩振动频率的精确解，实例应用表明，在四边简支条件下的计算结果与实验结果基本一致，说明该方法确定纯平荫罩的振动固有频率是可行的、有效的，所得结果为减小荫罩振动进而对其结构参数进行优化设计提供了依据。

NATURAL FREQUENCY OF THE PERFECTLY FLAT MASK

The mask vibration degrades the color purity in the perfectly flat color picture tube of high resolution television. This paper is concerned with some analytical methods for calculating the natural frequency of the perfectly flat mask. Then applying the basic theories of elasticity, we have established the governing equation for the horizontal oscillation of a thin plate and yielded the nat ural frequencies and modal shapes of the perfectly flat mask by modal analysis with its four edges simply supported. The results obtained are found to be satisfactory by comparison with experiments. It also shows that the method for determining the natural frequency of the perfectly flat mask is effective, simple and valid. The result provides a basis for optimal designs of structure parameters in order to reduce the perfectly flat mask vibration.