多孔薄膜荫罩热变形的有限元仿真设计

荫罩的热变形使电子束产生着屏偏移 ,进而导致了色纯变坏。本文采用大型软件ANSYS对 1 5英寸荫罩进行了热变形的有限元仿真 ,从而得到了电子束的着屏偏移。建立了包括阴极射线管 (CRT)里所有部件的完整的有限元模型。荫罩被建为无孔连续薄壳的模型 ,对它的表面导热系数和表面弹性模量作了等效的计算。考虑了弹簧片的预应力以及弹簧片和销钉的连接。这样可使我们的分析模型更接近真实情况。本文给出了 50 0、1 0 0 0、1 0 0 0 0s时的热变形和电子束着屏偏移。分析表明 :电子束着屏偏移的最大值发生在 50 0s左右。利用这种分析方法及研究结果可指导新型荫罩的设计和研制。

Finite Element Simulation of Thermal Deformation of Perforated Shadow Mask

Thermal deformation of the 15 inch perforated shadow mask was simulated with commercial software ANSYS based on finite element analysis,to predict the deformation induced beam landing shift,which considerably deteriorates color purity.Complete sets of finite element models have been developed for the mask as well as for all parts of the cathode ray tube (CRT) to best simulate the realistic situation.The shadow mask was assumed to be a continuous thin shell with no apertures;and its equivalent surface thermal conductivity and elastic modulus are evaluated carefully.Special considerations are also given to the stress distributions of the springs and pins.Three sets of the simulated results,at the time intervals of 500,1000 and 10000 seconds,of the thermal deformation and the corresponding beam land shifts are given,respectively.The results show that the beam landing shift maximizes at about 500 seconds after turning on the CRT.