Design, Analysis, and Optimization of LCD Backlight Unit using Ray Tracing Simulation

The design of BLU for LCD devices, whose goal is to achieve uniform illumination and high luminance across the LCD surface, requries an assistance of illumination design programs. The goal of this paper is to develop a design and analysis tool to model an efficient BLU. The rendering techniques traditionally used in the field of computer graphics are the usual tools of choice to analyze BLU. An analysis method based on Monte Carlo photon tracing to evaluate the optical performance of BLU is presented. An optimization technique based on direct search method, a simplex method by Nelder and Mead, to achieve an optimal uniform illumination is also discussed

Design, Analysis, and Optimization of LCD Backlight Unit Using Ray Tracing Simulation

The original publication is available at www.springerlink.com.The design of BLU for LCD devices, whose goal is to achieve uniform illumination and high luminance across the LCD surface, requries an assistance of illumination design programs. The goal of this paper is to develop a design and analysis tool to model an efficient BLU. The rendering techniques traditionally used in the field of computer graphics are the usual tools of choice to analyze BLU. An analysis method based on Monte Carlo photon tracing to evaluate the optical performance of BLU is presented. An optimization technique based on direct search method, a simplex method by Nelder and Mead, to achieve an optimal uniform illumination is also discussed

DESIGN AND MICROFABRICATION OF EDGE-LIT OPTICAL LIGHT CURTAINS

Plastic optical light guides can be used for a variety of interior and exterior vehicle light curtains such as cabin illuminators and automotive tail lights. The edge-lit wave guide is an optically transparent substrate coupled with one or more energy efficient light emitting diodes (LEDs). The light rays from the source travel through the substrate based on the principle of total internal reflection. If a surface of the optical wave guide is patterned with optical microstructures then the light rays will scatter and refract throughout the medium, primarily exiting opposite to the patterned surface. Uniform illumination over this active surface region is a function of the individual optical microstructure\u27s shape and the spatial distribution of the microstructures. The goal of this research is to investigate the light dispersion characteristics in both smooth and micro-patterned optically transparent substrates, and utilize optical simulation software to develop viable design approaches for fabricating small and medium sized light curtains. The study first identifies an appropriate optical microstructure (i.e. cylindrical indentations) that can be reliably imprinted on the surface of an optically transparent polymethyl-methacrylate (PMMA) substrate using a multi-axis micromilling machine. The optical simulation software Light Tools is then used to determine the most appropriate microstructure radius and spatial positioning of elements for uniform light distribution. The key design and fabrication parameters for near optimal performance are summarized and used to establish the process plan for the high-speed precision micromilling operations. Experiments are performed on several 100 mm x 100 mm x 6 mm polymer light guide panels (LGPs) including a customized design with a hexagonal arrangement of microstructures. Both interior and boundary regions of the sample LGPs are investigated for intensity distribution, optical transmission efficiency, and light loss. Although the experiments involve relatively small flat PMMA LGPs, the optical design and microfabrication methods can be readily extended to larger surface areas or curved optically transparent polymer substrates for contoured light curtains