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Uniformity tape is a microstructured thin-film mechanism for mixing and diffusing the light generated by light-emitting diodes (LEDs) in edge-lit digital displays, including monitors, televisions and signage. == Purpose == Compared to other sources of illumination, such as fluorescent and incandescent bulbs, LEDs are energy efficient and increasingly inexpensive. As hard-point light sources, however, LEDs have several significant limitations in edge-lit digital displays. First, the light generated by LEDs must be spread evenly to all parts of the display by a light guide (typically a plate of poly(methyl methacrylate)), which transports light by total internal reflection (TIR). Extraction patterns on the surface of the light-guide meter out the light and generate a uniform brightness distribution. Even with a light guide, dark zones can be noticeable along the injection edge closest to the LEDs. The existence of these dark zones requires that the injection edge be shielded by a border or bezel. The necessity of incorporating a bezel limits design options and the space available for displaying information. Dark zones also influence the spacing between LEDs, which is typically between about 9 mm and 11 mm; placing LEDS farther apart creates more pronounced dark zones. This, in turn, limits the ability of designers to reduce the number of LEDs in a display despite the cost advantages and increased energy efficiency of such a reduction. Furthermore, the poor light-mixing of current light guides makes digital displays highly sensitive to variations in LED color and brightness. Closely packed LEDs can also create thermal management issues. The first microstructured light-mixing tape is 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. Figure 1. Schematic of Tape on Light Guide and Tape Microstructure File:Uniformity tape-Wiki-fig1.tif 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Uniformity tape」の詳細全文を読む スポンサード リンク
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