| Abstract | Flexible optical sheets are thin large-area polymer light guide structures that can be used to create innovative passive light-harvesting and illumination systems. The optically transparent micro-patterned polymer sheet is designed to be draped over arbitrary surfaces or hung like a curtain. The light guidance sheet is fabricated by bonding two or more micro-patterned layers with different indices of optical refraction. By imprinting micro-optical elements on the constituent layers, it is possible to have portions of the optical sheet act as a light concentrator, near ‘lossless’ transmitter, or diffuser. However, the performance and efficiency of the flexible optical sheet depends on the overall curvature (κ) of the optical sheet and the relative orientation of incident light source. To illustrate this concept, the impact of key design parameters on the controlled guidance of light through a two-layer polydimethylsiloxane (PDMS) concentrator-transmitter-diffuser optical sheet is investigated using ray tracing simulation software. The analysis initially considers a flat (κ=0) PDMS optical sheet exposed to a collimated light source. The impact of sheet curvature (κ>0) on both system efficiency and illumination uniformity is then briefly explored. Critical design guidelines for creating multifunctional monolithic optical sheets are also summarized. |
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