真空荧光显示管激发功率分布的均匀性分析

Analysis of the Distribution Uniformity of the Exciting Power Density of Vacuum Fluorescent Display Tubes

平板荧光显示管采用直丝阴极的结构方式使电子激发阳极荧光粉的功率分布不均匀，举例计算，在空间电荷限制区，头尾单元的激发功率相差３倍以上，正对阴极丝的地方与阳极上下沿的激发功率相差约３倍。制管中尺寸公差和工艺技术也会影响激发功率分布。调整栅阴极距离和采用适当工作电路可改善功率分布的均匀性；在结构条件允许时，采用校正电路可消除其不均匀性；较高的亮度水平可减轻或消除人眼对亮度不均匀性的视觉感受。

The use of the straight-filament cathode in the flat-faced fluorescent display tube leads to the non-uniform brightness over the fluorescent coating on the electron-excited anode. The results we' ye obtained through calculations indicate that the exciting power density at the first display unit in the restricted space charge region is over three times as high as that at the last display unit, and that the exciting power density in the area right opposite the cathode filament is about three times as high as those at the upper and lower edges of the anode. Besides,the dimensional tolerance allowed and the technology adopted in making the tube also affect the distributon of the exciting power density. However,the adjustment of the distance between the grid and the cathode and the adoption of proper working circuits can improve the uniformity of the distribution of the exciting power density and if the design or structure permits,the non-uniformity can be eliminated by using a corrector circuit. In addition,a higher brightness also helps to reduce or eliminate the unpleasant effect caused by the non-uniformity of brightness on the eyes.