Studies of low-operating-voltage polymer-dispersed liquid crystals and their applications

• Main Authors: Zhe-Yuang Liang, 梁哲源
• Other Authors: Ko-Ting Cheng
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/85489581060370905217

碩士 === 國立中央大學 === 光電科學與工程學系 === 105 === In this thesis, a kind of monomer, P107, for fabricating polymer dispersed liquid crystal (PDLC) light shutters with low-operating-voltage has been investigated. The research herein can be divided into three parts. The first is to investigate the surface anchoring of the interfaces between LCs and polymer matrixes, and the transmittance versus voltage (T-V) curves in the PDLC. The experimental results show that the surface anchoring provided by P107 is weak so that such a PDLC light shutter shows low threshold voltage. The second is to investigate polarization-selective PDLC light shutters using crossed interdigitated electrodes. The interdigitated electrodes on the upper and bottom substrates can generate an electric field parallel to x- and y-axis, respectively. The incident linearly polarized light with linear polarization direction along y (x)-axis cannot (can) pass through the PDLC light shutter because the incident light does (does not) encounter obviously refractive index difference of LCs and polymers in the PDLC light shutter as the electrical field, whose direction is parallel to x (y)-axis, is applied onto the upper (bottom) substrate. The third is to study the temporarily stable state in dye-doped PDLCs (DDPDLCs). After turning off the applied AC field, the DDPDLCs can temporarily remain in transparent state for a short time. We proposed that the internal field, generated by the applied AC field, could result in the temporarily stable state. It can be used to approach a bistable PDLC shutter. Moreover, regarding the effect of the application of DC voltage, the DDPDLCs can be quickly switched back to scattering state after the applied DC voltage is switched off. It indicates that no temporarily stable state can be observed in this case.