Electrically Tunable Binary-Phase Fresnel Lens Based on Polymer Dispersed Liquid Crystal
This is a proposal for a Fresnel lens with an electrically tunable binary-phase made of polymer dispersed liquid crystal (PDLC), which has relatively fast response time and low applied voltage. Simple fabrication is the major advantage of the proposed method. In this study, NOA65 and E7 were utilized with weight ratios of 60 wt.%: 40 wt.%. There was also the utilization of a relatively low intensity UV-light, 0.53 mW/cm2. The duration time of exposure was about 30 hours. The performance improvement of the Fresnel lens resulted from the infiltration of large LC droplet into the PDLC film. The phenomenon of black cross strip patterns could be explained with the use of the electro-hydrodynamics theory. The diffraction efficiency of the proposed lens was from 31.1 % to 41 % with the changes of externally applied voltage. This work presents an effective approach to get relatively complete phase separation in PDLC. The proposed method also provides great potential in developing high performance Fresnel lens.
Copyright terms are indicated in the Republic of Lithuania Law on Copyright and Related Rights, Articles 4-37.
The copyright for articles in this journal are retained by the author(s), with first publication rights granted to the journal. By virtue of their appearance in this open access journal, articles are free to use with proper attribution in educational and other non-commercial settings.