No abstract

A novel polarized light-guide plate (LGP) for the illumination of liquid crystal display is proposed in this paper. For the substrate of the LGP, stress-induced birefringence is introduced to achieve the polarization state conversion. An aluminum sub-wavelength grating (SWG) is designed on the top surface as a polarizing beam-splitter (PBS). The structure of the novel LGP is optimized for three wavelengths of LEDs: 625nm, 533nm and 452nm, and high efficiencies of polarization conversion are obtained. The backlight system with the designed LGP does not require prism sheets and quarter wavelength plate. The backlight with the novel LGP achieved large gain in energy efficiency, and the peak luminous intensity is about 2 times higher than that of a conventional backlight.

Through the optimization of the main interval of the fractional order, an improved fast algorithm for numerical calculation of the fractional Fourier transforms is proposed. With this improved algorithm, the fractional Fourier transforms of a rectangular function and a Gaussian function are calculated. Its calculation errors are compared with those calculated with the previously published algorithm, and the results show that the calculation accuracy of the improved algorithm is much higher.

We propose a multiwavelength polarized backlight system (BLS) that is based on the stress-induced birefringence and the multilayer subwavelength grating. The polarized BLS requires no prism sheets and no quarter wave plate. Moreover, because of the high extinction ratio, the rear absorbing polarizer of the liquid crystal display panel is not required anymore. The proposed backlight can fully utilize the light, and the intensity at near normal angles is 2.3 times higher than that of a conventional unpolarized light emitting backlight.