Major Current Research Projects

• Liquid crystal materials: New chiral dopants have been found through systmatic organic synthesis. These dopants have much higher optical activity than conventional dopants. Applications include STN displays, cholesteric displays, optically active polmers, and reflective colour reflective colour polarizers.

• Characterization of pertilt angles of liquid crystals: We are developing techniques and equipment to measure liquid crystal tilt angles under various operating conditions, especially for STN displays.

• Bistable LCD by textured surfaces: By properly treating the PI alignment layer, we have shown that the liquid crystals can exist in 2 stable states at zero voltage. It is possible to switch the LCD between these 2 states electrically. Our goal is to develop a new type of bistable display requiring no standby power.

• Bistable cholesteric displays: Cholesteric displays can be either reflective or transparent at zero voltage. Switching between these 2 stable states can be done by properly controlled voltage pulses. This display requires no standby power and has many potential applications. We are working on methods to reduce the driving voltage and to increase the frame rate.

• Reflective LCD: Nematic STN with only one polarizer are being explored. Such devices are better than conventional ones in terms of brightness, contrast and resolution.

• New thin film transistor design: We have invented a new type of thin film transistor using polycrystalline silicon. This transistor has much higher on-current than conventional ones, and is capable of much higher speed as well. Our aim is to use this new transistor design to fabricate high speed drivers on the glass panel itself for active matrix LCD.

• SiGe TFT: Convential silicon TFT is always faced with the problem of processing temperature. This project examines the various aspects of SiGe TFT fabrication with the aim of reducing the processing temperature. The secondary aim is to produce higher speed transistors for the driver circuits.

• Active matrix LCD processing by chemo-mechanical polishing: We found that chemo-mechanical polishing can be used to enhance the electrical characteristics of thin film transistors by increasing their surface mobility. This project will lead to an increase in the operating speed of active matrix displays drivers.

• Digital driver design for active matrix LCD: Most drivers for LCDs are analog. However some operating modes of LCD are more suitable for digital driving. We are designing digital drivers that are capable of high speed operation and digital voltage level control.

• Liquid crystal on silicon: This projects deals with reflective active matrix displays that are fabricated on crystalline silicon. The advantage is that all the necessary circuits can be incorporated onto the same silicon chip as the pixels. This project leverages the sophisticated silicon CMOS technologies to produce high resolution, high aperture ratio displays.

• Chip on glass technology: Testing of bonding materials for bonding silicon chips onto glass. Properties of the bonds and reproducibility are measured.