偏極背光模組與偏極發光二極體模組之設計與製作

Design and Fabrication of Polarized Backlight Unit and Polarized LED Module

鐘基瑞(Chi-Jui Chung)

指導教授 ： 陳政寰

國立清華大學/工學院/動力機械工程學系/碩士(2011年)

摘要

由於液晶顯示器輕、薄的特性，已被廣泛的使用在各項資訊顯示裝置上，但目前液晶顯示器的光使用效率僅4-7%，其主因之一為使用吸收式的下偏極片。超過50%的光能量被下偏極片吸收，以產生偏極光供液晶層調控。
本論文針對側光式和直下式背光模組分別提出偏極光解決方案。其一為高偏極消光比、高增亮、低色偏的側光式LED偏極背光模組，利用光圈限制的導光板搭配複合式的金屬線偏極膜片，實現了偏極回收、提升中心輝度的概念，同時達成一高效率的背光模組。實作方面，利用超精密加工技術製作元件，搭配商用金屬線偏極片完成一2.5吋的背光模組進行設計驗證。實驗結果發現，背光模組的偏極中心輝度提高74%，且光使用效率提升39%。
其二為偏極白光LED模組，可應用於直下式背光模組，或是其他偏極光的照明需求，如防眩光照明。本模組具有一奈米金屬線與介電質奈米結構垂直堆疊的金屬線偏極片，搭配半波片，以實現偏極轉換的概念。此設計增加了LED出光的偏極化程度，同時也提升了直下式背光的總效率。實作方面，將使用奈米壓印製成的光阻結構膜，黏貼於商用的金屬線偏極片上，以實現垂直堆疊的金屬線偏極片，和UV膠封裝於LED晶片上，以完成整體模組。實驗結果發現，LED偏極效率提升至72%，整體增益為1.4倍。

關鍵字

金屬線偏極片 ； 液晶顯示器背光模組 ； 發光二極體照明 ； 偏極轉換 ； 偏極回收

並列摘要

Liquid crystal displays (LCDs) have been widely used in large variety of applications as information display devices due to the compact size and lighter weight. However, the light efficiency in current LCDs is only 4-7%. One of the major losses of LCDs is the absorption of down polarizers. In order to obtain polarized light for liquid crystal layer to manipulate light, over 50% of energy is absorbed.
Solutions have been proposed to edge-lit and direct-lit backlight system respectively for enhancing light transmission efficiency in this thesis. For edge-lit backlight unit, a high extinction ratio, high brightness enhancement, and low color shift backlight unit has been proposed which features with a aperture-limited light guide plate and a hybrid wire-grid polarizer. Concept of polarization recycling and brightness enhancement are realized in the backlight unit so as a high efficiency backlight unit. To evaluate the design, a 2.5 inches backlight unit with a commercial wire-grid polarizer and components fabricated by ultra-precision diamond tooling is demonstrated. By experimental results, polarized brightness is enhanced by 74%, and optical efficiency is improved by 39%.
For direct-lit backlight system, a white light polarized LED module has been proposed. It can be also used in other application such as anti-glare illumination. The module features with a dielectric-metal multilayer nanostructure wire-grid polarizer and half-wave retarders to realize the polarization conversion. The module increase the degree of polarization at the outlet of the whole packaged LED module, so as to improve the overall energy efficiency of direct-type LED backlighting. To evaluate the design, a commercial wire-grid polarizer was laminating with a nano photoresist film made by nano imprint process to become the cross stacking wire-grid polarizer. The cross stacking wire-grid polarizer and UV resin was packaged on a LED chip. By experimental results, polarization efficiency is increased to 72%, and the overall gain is 1.4X.

並列關鍵字

wire-grid polarizer ； LCD backlighting ； LED illumination ； polarization recycling ； polarization conversion

參考文獻

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