In this dissertation, color filters are applied onto the monochrome liquid-crystal-on-silicon (LCOS) microdisplays to produce a new breed of color filter LCOS (CF-LCOS) microdisplays. The processing of color filters is compatible with silicon very-large-scale-integrated (VLSI) fabrication. The color filters are also used in liquid crystal display (LCD) for color. It is advantageous to leverage on both the silicon VLSI and LCD infrastructures for this novel but practical CF-LCOS microdisplay....[ Read more ]

In this dissertation, color filters are applied onto the monochrome liquid-crystal-on-silicon (LCOS) microdisplays to produce a new breed of color filter LCOS (CF-LCOS) microdisplays. The processing of color filters is compatible with silicon very-large-scale-integrated (VLSI) fabrication. The color filters are also used in liquid crystal display (LCD) for color. It is advantageous to leverage on both the silicon VLSI and LCD infrastructures for this novel but practical CF-LCOS microdisplay.

The color filter process on silicon was developed in this dissertation research to achieve 3 μm resolution, 1000Å flatness and 0.1μm alignment accuracy with the pixel array. Mechanical rubbing and photoalignment technology were explored and compared for the LC cell assembly. Important optical and electrical parameters of color filters were extracted to establish an electro-optical model of the CF-LCOS microdisplays for device simulation. Thermal, chemical and light stability characterizations were performed to ensure the stability of color filters and the CF-LCOS microdisplays.

A three-dimensional (3D) optical modeling was further developed to study fringing field effect in small color pixels of the CF-LCOS microdisplays. The simulation results were verified with the experimental ones. With this 3D optical analysis as a tool, the color fringing effect was analyzed with different display structures. Minimizations of the fringing field effect through pixel arrangement, rubbing direction and LC mode could lead to a CF-LCOS microdisplay of good 63% NTSC color, 300:1 contrast and 23% optical reflectance. The relations of the color fringing effect with pixel size and thickness of color filters were also better understood for the design and optimization of the CF-LCOS microdisplays.

Finally, the vertical-aligned (VA) CF-LCOS microdisplays were processed, analyzed and compared with the twisted nematic (TN) ones. Optimizations of the VA CF-LCOS microdisplays were through pretilt angle, pixel size and polarizations.