In this research, a new developed optimization method for light guide plate design is proposed in order to achieve its exiting-light uniformity by varying the light-scattering microstructure sizes or pitches at different areas of a liquid crystal display (LCD) light guide plate. The light-scattering hemispheric microstructures on a light guide plate are studied in this paper due to less light absorption compared to the conventional V-cut pattern design. The results show success in uniformity. To validate the effectiveness of this design method on the improvement of exiting-light uniformity, the “advance system analysis program” (ASAP) simulation is performed. Based on the proposed design method, it is illustrated that the exiting-light uniformity significantly improves by more than 13% for the case study.

We demonstrate a nanosecond fiber laser with tunable central wavelengths and narrow spectral bandwidths suitable for high-power amplification. Spectrally narrowband flat-top nanosecond pulses were generated at the fundamental repetition rate of 1.9 MHz in an Yb-doped fiber laser, which could be tuned in central wavelength from 1033 to 1053 nm by changing the nonlinear polarization rotation in the fiber laser cavity. In particular, such flat-top nanosecond pulses could be tuned around 1030 nm to match the gain bandwidth of ytterbium-doped double-clad fibers or 1053 nm to match the maximum gain in Nd-doped phosphate glass. The pulse duration could be changed from 1 to 15 ns by varying the pump power or laser polarization evolution in the cavity. By using an ytterbium-doped single-mode fiber preamplifier and a two-stage large-mode-area Yb-doped double-clad-fiber power amplifier, 280-W average power with pulse duration of 3 ns was obtained at 1034 nm.

Abstract— This paper describes the development of a design method for a prism pattern for an LCD light‐guide plate to improve the uniformity of its exiting light. First, the prism surface of the light‐guide plate is divided into several equal regions. With the aid of ASAP simulation, this method uses the mean light flux of all regions as a reference value to adjust the distribution density of the prism pattern for each region. Curve fitting is then performed to provide a smoothly changing distribution density for further improvement of the exiting light uniformity. ASAP results demonstrate that the illuminance uniformity for a 2.5‐in. light‐guide plate is substantially improved from 45% to 90.9% by using this design method.

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