High Transmittance Polymer-Stabilized Blue-Phase LCDs With Double-Sided Patterned Electrodes

• Main Authors: Chia-Liang Chang, 張嘉良
• Other Authors: Wing-Kit Choi
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/88801659033647443609

碩士 === 國立臺灣大學 === 光電工程學研究所 === 104 === Liquid crystal technologies have been used in our daily life. In addition to displays such as LCD TVs, tablet PCs, smart phones and large advertising panels, liquid crystal’s bright and dark states can also be used for the application in electro-optic switches, such as electronic windows. Liquid Crystal plays an important role in products of technology for people’s life. Manpower and resources have been invested in all of the mentioned technology. In recent decades, scientists have been investigating and developing of a new type of liquid crystal material called Blue Phase Liquid Crystal (BPLC). BPLC occurs as a highly twisted chiral nematic liquid crystal cooling down from the isotropic phase. However, its temperature range is only about 1K. In recent years, researchers proposed to use polymers to improve the temperature range of BPLC from 1K to around 60K, so-called polymer-stabilized blue phase liquid crystal (PS-BPLC). As a result, PS-BPLC has been actively researched in recent years for next-generation displays due to its attractive features such as fast response time of sub-millisecond, no alignment required and isotropic off-state. However, PS-BPLC display has so far not been in mass production. One of the major obstacles that needs to be solved is its high operation voltage. This thesis is the use of simulation software (Techwiz) to design the doubled sided electrode, so that it can reduce the operating voltage of polymer-stabilized blue phase LCDs. Although its fabrication may be difficult, it offers a potential way of achieving a very low operation voltage for PS-BPLCD. In this thesis, we demonstrate a further possible improvement on this design by including a protrusion electrode scheme to this double sided IPS electrode design. This results in the generation of stronger horizontal electric fields to reduce the disclination or “dead zone” areas resulting in higher transmission and lower operation voltage. We tried to vary different parameters such as electrode gap (L)、electrode height (H) and cell gap (G) in order to get the best possible results. Moreover, we will also design other possible new potential designs such as the use of a new double-sided slanting electrode to lower the operation voltage of a PS-BPLC display. By using oblique electric field to increase the level of the horizontal electric field, this new design can improve interference effect of the electric fields in the middle part of liquid crystal cell that is caused by the double sided IPS electrodes. It can enhance the transmittance and reduce the operating voltage of PS-BPLCD. Finally, we make some analysis and comparisons between two designs of double sided electrode structures.