液晶顯示器及相關應用的發展至今已相當成熟，目前大量量產之液晶顯示器皆運用偏振光學的特性，如半波板(Half-wave plate)、扭轉向列型液晶 (Twisted nematic liquid crystal，簡稱TN-LC)等結構。此外旋轉線偏振光偏振方向之方法亦相當受到重視，如TN-LC結構、菲涅耳菱鏡(Fresnel rhomb)及法拉第效應(Faraday effect)等，而上述三種旋轉線偏振方向的方法各有其優缺點，以TN-LC為例，TN-LC須滿足Mauguin condition方能使任意波長線偏振光皆具備偏振旋轉特性，但並非任意線偏振角度入射皆能達成相同之偏振旋轉效果，其限制須將線偏振方向設定為平行液晶快軸或慢軸方向才能將其線偏振方向有效旋轉至所設定的方向，因此若能開發出任意波長及任意線偏振角度入射皆能有效達成線偏振旋轉效果的線性偏振旋轉器，相信其應用將極為廣大且多元。;Several optical devices, which are capable of manipulating polarization state of linearly polarized lights (LPLs), have been widely studying for several decades. Fresnel rhomb and some optical devices based on the famous Faraday’s effect can rotate the polarization direction of the input LPLs. Because of their unacceptable sizes for practical applications, these devices are not suitable for portable devices. Regarding liquid crystal (LC) polarization rotators, twisted nematic LCs (TNLCs), characteristic of their electrically switchable property and polarization rotation of LPLs based on the waveguide effect, have been extensively applying in all fields of optics and photonics.
