the first microstructured light-mixing tape was scheduled to be introduced in late 2011. 3m™ uniformity tape is designed to be applied directly to the injection edge of a light guide for the purpose of defusing the light generated by leds. the microstructure consists of linear aspheric prisms (figure 1) that are aligned perpendicular to the plane of the guide. the size of the microstructure is small compared to the size of the leds, typically on the order of 12-50 μm. as a result, no registration of the tape with the leds is required.