A three-dimensional/two-dimensional (3-D/2-D) convertible display was proposed. The display system offers 2-D images via the traditional display technology and offers 3-D images via the computer-generated hologram (CGH) technology. In this system, 2-D and 3-D images are generated from the same amplitude-modulated spatial light modulator (SLM). In the 2-D display mode, the panel displays an amplitude-modulated image and the 2-D image is projected on a polarization-dependent diffuser (PD) screen. In the 3-D display mode, the SLM panel displays CGHs to generate 3-D images. The zero-order diffraction of the amplitude-type CGH will be blocked by a spatial filter (SF), which is designed by a polarizer. Furthermore, a liquid crystal element was employed to modulate the polarization state of the reconstructed light to let the 3-D image quality not to be reduced by the PD. Finally, the proposed system can offer 2-D and 3-D images both clearly. The system suppresses the zero-order diffraction noise of the amplitude-type CGH system successfully.
Liquid crystal (LC) lenses have attracted much attention, owing to the light weight and an adjustable focal length without mechanically moving parts. Among the developed LC lenses, the hole-patterned LC lens has a convenient fabrication process, a simple addressing scheme, and widely tunable focal range. Nonetheless, a thick dielectric layer (TDL) has to be inserted between the hole-patterned electrode and the LC layer to distribute the fringing electric field throughout the center of the aperture hole (AH). However, the inserted TDL significantly increases the operation voltage of the LC lens. In this paper, we propose a hole-patterned LC lens with a wide diameter of 6 mm. In our design, a floating ring electrode (FRE) is embedded into the interface between the dielectric layer and the LC layer. This structure confines the electric field in the hole patterned area, therefore assists in distributing the fringing electric field throughout the LC layer and thus assists in tilting the LCs in the AH center of the lens. Therefore, the dielectric layer used in the conventional hole-patterned LC lens can be effectively decreased. The decreased thickness of the dielectric layer provides the FRE LC lens with the advantages of lower operation voltage and large tunable focal range. With a voltage of 40 V, the introduced floating ring electrode modulates the phase retardation of the LC lens in a nearly perfect quadratic form with wavefront error approaching 0.07 . The design principle, simulation and fabrication of the LC lens are demonstrated in this paper.
Previously, we have established hole-patterned liquid crystal (LC) lens consisted of a floating ring electrode (FRE LC lens).
However, while the applied voltage is given across the FRE LC lens, the disclination lines are induced as conventional hole-patterned
LC lens, degrading the lens quality. To avoid the appearrance of disclination lines, the polymer stabilization is adopted to construct
the FRE LC lens. The polymer stabilized FRE LC lens not only excludes the occurrence of the disclination lines during applied
voltages but also preserves optical properties similar to the ordinary FRE LC lens.