Liquid Crystal (LC) has been combined in integrated optical devices e.g. optical switches to achieve large matrix optical components. Except for optical switches used in optical communication system, TIR-based switch could also be applied to display area. In recent years, researchers have investigated the displays based on the concept of TIR using electrophoresis material and polymer dispersed liquid crystal (PDLC). The problems are poor contrast ratio, slow response time and additionally driving voltage of PDLC is much higher than the capacity of standard super twist nematic (STN) driver....[ Read more ]

Liquid Crystal (LC) has been combined in integrated optical devices e.g. optical switches to achieve large matrix optical components. Except for optical switches used in optical communication system, TIR-based switch could also be applied to display area. In recent years, researchers have investigated the displays based on the concept of TIR using electrophoresis material and polymer dispersed liquid crystal (PDLC). The problems are poor contrast ratio, slow response time and additionally driving voltage of PDLC is much higher than the capacity of standard super twist nematic (STN) driver.

To calculate electromagnetic wave transmission in stratified media, 4 X 4 matrix methods have been used for a long time. However, in the context of TIR, with incident angle larger than critical angle, the traditional 4 X 4 matrix is not suitable due to the instability of the system.

We have recently proposed an improved matrix method to calculate optical response of LC layers, which works stably under normal incidence and also beyond-critical-angle incidence. To construct a passive matrix liquid crystal display based on TIR effect, one-dimensional optical analysis is not enough for the display since TIR effect is very sensitive to the refractive index change caused by the reorientation of molecules. Thus, multidimensional dynamic simulation and optical analysis are necessary in the modeling of the display since electric field under patterned ITO is not uniform and fringing effect need to be considered. A 3D simulation program recently developed has been used to modeling the 2D and 3D dynamic response of the TIR display.

Based on the theoretical analysis and the modeling tool we have developed, optimizations of all the related parameters for the TIR-based LC switch, including the operation modes, LC mixtures, refractive index of glass, anchoring conditions of alignment layer, and influence of ITO and dielectric layer have been conducted. Optimal configuration has been obtained and the prototype has been fabricated accordingly.