Mechanical modeling of tiled Liquid Crystal on Silicon (LCoS) microdisplay

Abstract

Liquid Crystal on Silicon (LCoS) microdisplays is a viable technology for applications in projection and near-to-eye displays. As the performance of the microdisplay is related to the image quality, the characterization and understanding of the critical factors affecting the image quality need to be studied. The overall objective of this work is to establish a quantitative understanding of the functional performance of the tiled LCoS microdisplay as a function of thermal gradients and mechanical stress. The initial design calls for a three-tile configuration. Such a device needs to be assembled to very exacting tolerances, and must be able to undergo all of the assembly, and operating conditions without significant changes in the critical parameters, namely tile gap, cell gap and/or, silicon tile warpage. The ongoing work deals with the thermomechanical performance simulation of the 3-tile LCoS microdisplay during operating conditions. The focus of this work is to maintain the critical parameters, cell and tile gap, within the prescribed tolerances. Finite element analysis has been used for this purpose and three-dimensional quarter symmetry models have been built to conduct a thorough study of the effect of operating conditions on the critical parameters. The proposed initial design was further improved by conducting parametric studies on material and dimensional parameters. Further, the sub-modeling technique has been used to conduct convergence studies that are essential in finite element analysis.