Thermal deformation of microstructure diffuser plate in LED backlight unit

Thermal deformations of a microstructure diffuser plate in an LED backlight unit subjected to a long period of illumination were studied. Mechanical properties of the microstructure diffuser plate in the LED backlight unit were determined and verified. Rather than using data from the relevant literature, accurate finite element solutions were obtained by using a microtensile test and thermo‐mechanical analyzer to calculate the Young's modulus, Poisson's ratio, and thermal expansion coefficient of the microstructure diffuser plate. The measured mechanical properties were used as input data in finite element simulations. Comparisons of the finite element analysis results with the experimental measurements made using strain gauge yielded differences of less than 3%. Thermal warpage phenomena of the microstructure diffuser plate at various temperatures are discussed. Thermal deformations are also compared between the conventional diffuser plate and the microstructure diffuser plate.