Thesis Examination Committee
Prof Dik Lun LEE, CSE/HKUST (Chairperson)
Prof Hoi Sing KWOK, ECE/HKUST (Thesis Supervisor)
Prof Vladimir CHIGRINOV, ECE/HKUST (Thesis Co-supervisor)
Prof Philip J BOS, Liquid Crystal Institute, Kent State University (External Examiner)
Prof Chik Patrick YUE, ECE/HKUST
Prof Zhiyong FAN, ECE/HKUST
Prof Jiannong WANG, PHYS/HKUST
High resolution displays are always in highly demand and especially popular recently together with the prevailing virtual reality and augmented reality technology. Utilizing fast switching ferroelectric liquid crystal, we can apply the field sequential color to display panel: from micro-displays to flat panel displays.
The fast vertical aligned nematic liquid applied to LCoS is used in head up displays for auto-motive with a wide temperature range from 10°C to 80°C. Although the rubbing mura can be solved by post annealing, the response time in the order of sub-millisecond is not possible to avoid the color break-up. Electrically suppressed helix ferroelectric liquid crystal on silicon projection with microsecond response time using pulse width modulation to generation grey level is achieved on digital Jasper Display Corp. CMOS backplane. This is proved by us to be a better option for FSC LCoS.
FSC ESHFLC is further studied and applied to active matrix TFT array for the larger size and commercial market. Using 3T1C pixel circuit, we successfully convert digital signal to the analog and have achieved at least 8-bit gray level color. The color spectrum measured is 105% NTSC in CIE 1931. Specific driving frame is designed to solve the DC compensation issue for Ferroelectric liquid crystal. High voltage acceleration for compensation is also investigated to over the issues. Color breakup suppress methods for FSC are applied to ESHFLC to improve the quality for motion rainbow suppress.
Considering 3T1C pixel circuit limits the high resolution and ppi of the panel, deformed helix ferroelectric liquid crystal based on molecule re-distribution within a pitch is more attractive for its attributes of more compatible with the current driving scheme and pixel circuit. Single alignment layer boundary condition is proposed to improve the low contrast ratio issues. This certain constrain suppresses the ferroelectric domains appear in traditional double side alignment and thus improves the electro-optical performance.