Liu Cheng-Kai, Li Ming-Hsien, Ting Chi-Lun, Fuh Andy Ying-Guey, Cheng Ko-Ting
Department of Optics and Photonics, National Central University, Taoyuan 320, Taiwan.
Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Nantou County 545, Taiwan.
Polymers (Basel). 2020 Dec 17;12(12):3031. doi: 10.3390/polym12123031.
Multiple-color reflectors using bichiral liquid crystal polymer films (BLCPFs) are investigated. The BLCPFs consist of alternate layers of two different single-pitch cholesteric liquid crystal (CLC) layers, named CLC#A and CLC#B. The thickness of each CLC layer equals its single pitch length. The optical properties in terms of reflections, reflection-wavelength ranges, and distributions of reflection spectra of the BLCPFs that result from the fixed pitch length of CLC#A along with the decrease of the pitch length of CLC#B are qualitatively simulated and investigated. The results indicate that the above optical properties of the BLCPFs depend on the LC birefringence and pitch lengths of CLC#A and CLC#B layers. The concept of fabrication method of the BLCPFs by using polymerizable CLCs and thin films of poly(vinylalcohol) or photoalignment materials is discussed. They have potential practical applications in functional color filters, asymmetrical transmission systems, etc., owing to the multiple reflection bands of BLCPFs. Moreover, the BLCPFs, which can enhance the color gamut and light-utilization efficiency of light sources/LC displays, are reported herein.
研究了使用双螺旋液晶聚合物薄膜（BLCPF）的多色反射器。BLCPF由两个不同的单螺距胆甾相液晶（CLC）层交替排列组成，分别命名为CLC#A和CLC#B。每个CLC层的厚度等于其单螺距长度。定性模拟并研究了由于CLC#A的螺距长度固定以及CLC#B的螺距长度减小而导致的BLCPF在反射、反射波长范围和反射光谱分布方面的光学特性。结果表明，BLCPF的上述光学特性取决于CLC#A和CLC#B层的液晶双折射和螺距长度。讨论了使用可聚合CLC以及聚乙烯醇薄膜或光取向材料制造BLCPF的方法概念。由于BLCPF具有多个反射带，它们在功能性彩色滤光片、不对称传输系统等方面具有潜在的实际应用。此外，本文报道了能够提高光源/液晶显示器色域和光利用效率的BLCPF。
