Introduction XY| -qd}A Backlights are used for compact,portable, electronic devices with flat panel Liquid Crystal Displays (LCDs) that require illumination from behind. Applications include devices as small as hand-held palm pilots and as large as big-screen TVs. Goals for backlight design include low power consumption,large area with small thickness, high brightness, uniform luminance, and controlled viewing angle, either wide or narrow. To achieve these challenging design goals with a cost effective and timely solution, it is necessary to use computer-aided optical design tools to expedite the design. This paper describes fea-tures in ORA’s LightTools? illumi-nation design and analysis software that enable the development of state-of-the-art backlight designs.
ANCgch\ Optical Design and Analysis Tools for Backlights t
MB;GIb # Illumination or lighting systems take light from one or more sources and transform it in some way to produce a desired light distribution over an area or solid angle. Illumination design software must be able to model the geometric and optical properties of different types of light sources and transforming elements, and it must also be able to evaluate the paths of light using optical ray tracing through the model to calcu- late the final light distribution.
M{7EFTy!y The light distributions are calculated using Monte Carlo simulations to calculate illuminance, luminance, or luminous intensity over the desired areas and/or angles. Rays are started from random locations and direc- tions from the source(s), traced through the optical system, and col- lected on receivers. Illuminance can be calculated for rays collected on surface receivers and intensity for rays collected on far field receivers. By defining a luminance meter for surface receivers, the spatial or angular variation of luminance can be calculated from that surface.
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