This thesis is mainly composed of four parts of the research on liquid crystal (LC) Fresnel lenses. In the first part, the color performance of the LC Fresnel lens is studied and the feasibility of using a switchable LC Fresnel lens as a color filter is evaluated. In the second part, two different types of nematic LC Fresnel lenses are investigated. One is based on alternate twisted nematic (TN) and planar aligned (PA) regions. The other is based on a single-side-patterned photoalignment layer. Both of the LC Fresnel lenses are fabricated by means of two-step photoalignment technique. In the third part, a fast switchable ferroelectric liquid crystal (FLC) Fresnel lens based on multiple planar alignment domains is demonstrated. Two switchable modes, FOCUS/OFF and FOCUS/DEFOCUS, o...[ Read more ]

This thesis is mainly composed of four parts of the research on liquid crystal (LC) Fresnel lenses. In the first part, the color performance of the LC Fresnel lens is studied and the feasibility of using a switchable LC Fresnel lens as a color filter is evaluated. In the second part, two different types of nematic LC Fresnel lenses are investigated. One is based on alternate twisted nematic (TN) and planar aligned (PA) regions. The other is based on a single-side-patterned photoalignment layer. Both of the LC Fresnel lenses are fabricated by means of two-step photoalignment technique. In the third part, a fast switchable ferroelectric liquid crystal (FLC) Fresnel lens based on multiple planar alignment domains is demonstrated. Two switchable modes, FOCUS/OFF and FOCUS/DEFOCUS, of the FLC Fresnel lens have been constructed. The proposed diffractive element provides fast response time, high diffraction efficiency and simple fabrication. In the fourth part, a novel liquid crystal Fresnel lens display (LCFLD) is proposed and demonstrated. The LCFLD comprises a liquid crystal Fresnel lens array, a (patterned) holographic screen or fluorescent screen, and a TFT array. The difference between the focused state and the defocused state of the switchable LC Fresnel lens is made use of so that the switchable LC Fresnel lens array helps to form the contrast distribution over the whole screen and display information. This is just a starting line for the promising LCFLD and it deserves more investigation.