加固液晶显示器高温环境下热应力探究

Thermal Stress Study of Rugged LCDs

为了探究加固液晶屏高温下热应力影响,建立了基于ANSYS的液晶屏复合结构的有限元分析模型,模拟分析了二维模型等效应力和液晶层上边界Y方向应力的分布情况。仿真结果表明,当环境温度上升到70℃,胶层中气泡和裂纹附近会发生应力集中,液晶盒上边界也会发生相应位置Y方向应力集中。将三种光学胶实际测试的力学数据代入模型分析发现,光学胶的弹性模量和热膨胀系数越大,引起的应力集中也越明显。基于模拟分析,胶层中含有裂纹时液晶屏所受应力最大,因此加工中应避免胶层出现裂纹。在对液晶屏粘贴ITO玻璃时,应该选用弹性模量和线膨胀系数较小的光学胶。

In order to analyze the effects of the thermal stress on rugged LCDs under high temperature, a finite element model of a LCD laminated structure is established. This paper describes the equivalent stress of a two-dimensional model and the Y-direction stress on the LC cell. The simulation results show that when the ambient temperature rises to 70%, the stress concentration happens near the bubbles and cracks in the optical adhesive layer as well as the Y-direction stress concentration on the LC cell. The actual parameters of three kinds of optical adhesive are measured and input into the model. The simulation results indicate larger the elastic modulus and thermal expansion coefficient of optical adhesives, larger the stress concentration. Based on the simulation results, the stress on the LC cell is largest when there are cracks in the optical adhesive, which should be avoided in processing. The optical adhesives with small elastic modulus and thermal expansion coefficient are suggested when laminating ITO glass onto LC panel.