Fast-Response Liquid Crystal Microlens

Abstract

Electrically tunable liquid crystal microlenses have attracted strong research attention due to their advantages of tunable focusing, voltage actuation, low power consumption, simple fabrication, compact structure, and good stability. They are expected to be essential optical devices with widespread applications. However, the slow response time of nematic liquid crystal (LC) microlenses has been a significant technical barrier to practical applications and commercialization. LC/polymer composites, consisting of LC and monomer, are an important extension of pure LC systems, which offer more flexibility and much richer functionality than LC alone. Due to the anchoring effect of a polymer network, microlenses, based on LC/polymer composites, have relatively fast response time in comparison with pure nematic LC microlenses. In addition, polymer-stabilized blue phase liquid crystal (PS-BPLC) based on Kerr effect is emerging as a promising candidate for new photonics application. The major attractions of PS-BPLC are submillisecond response time and no need for surface alignment layer. In this paper, we review two types of fast-response microlenses based on LC/polymer composites: polymer dispersed/stabilized nematic LC and polymer-stabilized blue phase LC. Their basic operating principles are introduced and recent progress is reviewed by examples from recent literature. Finally, the major challenges and future perspectives are discussed. OPEN ACCESSMicromachines 2014, 5 301

Phase Structure Recording in a Nematic Side-Chain Liquid-Crystalline Polymer

“…Various methods of producing lenses were reported for low molecular weight NLCs (including creation of polymer networks) [18][19][20][21][22][23][24][25]31,32] and amorphous polymers [26]. In this study, we applied the optical recording of the phase structures in the NLCP for the formation of negative and positive lenses.…”

“…In this case the steady-state inhomogeneous NLC structure reveals itself upon application of external ac field. This method was used to record conventional [18][19][20][21][22] and Fresnel [23][24][25] lenses. Phase structures, including microlens arrays [26], can be recorded in amorphous polymers.…”

Drop‐on‐Demand Inkjet Printing of Thermally Tunable Liquid Crystal Microlenses

“…The position of the maximum of this plot was then used to estimate the focal length, , to within an accuracy of , as seen in Figure b. Figure c shows an example of the variation in intensity along the x ‐direction of a 140 μm diameter lens at the focal plane and demonstrates good focussing properties with an optical transmission of 74%, comparable to other LC microlenses …”

“…This has the effect of reducing the number of components required during manufacturing and allows smaller and more compact devices to be produced. Current methods for achieving a tunable microlens include liquid filled elastic lenses, gradient refraction index (GRIN), and LC lenses . Liquid‐filled lenses rely on complex microfluidic systems to deform the lens surface and subsequent focussing properties.…”

Special Issue on Microlenses

“…Xu et al [1] provide a thorough review of how to improve the response time of liquid crystal (LC) based tunable-focus microlenses. The basic operating principles and recent progress are introduced and reviewed for two types of fast-response microlenses based on LC/polymer composites: polymer dispersed/stabilized nematic LC and polymer-stabilized blue phase LC.…”