Application of photoalignment technology to liquid-crystal-on-silicon microdisplays

We applied photoalignment technology to liquid-crystal-on-silicon microdisplays and characterized their performance. A three-step photoexposure method was developed to solve problems with alignment disturbances on reflective silicon panels. The azimuthal and polar anchoring energies of photoalignment layers produced by this method were high and comparable with that of rubbed polyimide layers. We assembled both the rubbed and photoaligned microdisplays on a MTN 90 degrees configuration for characterization and comparison. These two kinds of silicon microdisplays had good and comparable characteristics in terms of contrast, response time, voltage holding ratio and residual DC charge. The rubbed microdisplays were more uniform, which we attributed to a more mature fabrication technology, while the photoaligned microdisplays had far fewer defects due to the noncontact nature of the photoalignment technology.