Capillarity and Wetting Phenomena: Drops, Bubbles, Pearls, Waves

Polymer-stabilized optically isotropic liquid crystals, including blue phases, are emerging as a strong contender for next-generation display technology because they exhibit some revolutionary features such as no need for surface alignment, submillisecond response time, isotropic dark state, and cell gap insensitivity. The basic material properties, including electric field-induced birefringence, dispersion relation of Kerr constant, and temperature dependent Kerr constant, are reviewed. Recent progress on blue phase liquid crystal material development and device structures for lowering the operating voltage are introduced. Promising applications and remaining technical challenges are also discussed.

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Polymer-stabilized optically isotropic liquid crystals for next-generation display and photonics applications

A polymer-stabilized blue phase liquid crystal (BPLC) composite with a large Kerr constant (K∼13.7 nm/V2) is developed and its electro-optic properties characterized. In addition to the reduced operating voltage, this BPLC also exhibits a fast response time (∼1 ms), high contrast ratio (>1000:1), and relatively small hysteresis (<6%). It will undoubtedly accelerate the emergence of BPLC for next-generation display and photonic devices.

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A large Kerr constant polymer-stabilized blue phase liquid crystal

We demonstrate a tunable phase grating using a polymer-stabilized blue phase liquid crystal Because of the electric-field-induced rectangularlike phase profile, a high diffraction efficiency of 40% is achieved Moreover, this device shows submillisecond response time The proposed tunable phase grating holds great potential for photonics and display applications

/pdf/high-efficiency-and-fast-response-tunable-phase-grating-n4osxijnnu.pdf

High-efficiency and fast-response tunable phase grating using a blue phase liquid crystal.

Lenses with tunable focal length play important roles in nature by helping species avoid predators and capture prey. Many practical devices mimic lens concept for imaging, sensing, and detection. This review covers fundamental optics of lenses and its extension to lenses made of liquid crystals (LCs). Three main types of LC lenses are described, namely, lenses with curved surfaces, flat gradient-index lenses and composite lenses. The review discusses advantages of LC lenses over their isotropic counterparts, challenges in their fabrication and control, as well as a variety of potential applications. We also discuss the current challenges associated with nematic LC lenses and their solutions. LC lenses are already having significant impacts on optics and optometry, and these impacts will grow with discovering new LC materials and new lens designs.

Liquid crystal lenses with tunable focal length

We demonstrate polarizer-free and fast response microlens arrays based on optical phase modulation of polymer-stabilized blue phase liquid crystal (PSBP-LC). Polarization-independent optical phase shift is because the propagation of an incident light is along the optic axis of PSBP-LC, and birefringence of PSBP-LC induced by Kerr effect results in electrically tunable optical phase shift. The measured optical phase shift of a PSBP-LC phase modulation is around π radian at 150 Vrms for the cell gap of 7 μ. The response time is about 3 ms. The focal length is around 13.1 cm at 100 Vrms.

https://ir.nctu.edu.tw:443/bitstream/11536/5706/1/000275825200066.pdf

Polarizer-free and fast response microlens arrays using polymer-stabilized blue phase liquid crystals

A switchable surface using a liquid crystal and polymer composite film (LCPCF) based on phase separation
between liquid crystals (LC) and polymers after photopolymerization is developed recently. The wettability of
LCPCF is electrically tunable because of the orientation of liquid crystal directors anchored among the
polymer grains under an in-planed electric field. A water droplet on the top of LCPCF can be manipulated
under an inhomogeneous electric field on the LCPCF owning to the wettability gradient. The dynamics of a
droplet of human sperms on the LCPCF is demonstrated as well. Three motions of sperm droplets are
observed: the droplet collapse and the droplet stretch,. We found that the dynamics, concentrations, and
activities of spermatozoa, affect the motions of a sperm droplet. The potential applications of LCPCF are
polarizer-free displays, liquid lenses, and the microfluidic device in assisted reproductive technology (ART)

https://ir.nctu.edu.tw:443/bitstream/11536/146276/1/cc63ee86fa7d87f7fe315b8785740029.pdf

The dynamics of human sperm droplets on a liquid crystal and polymer composite film

A single pixel of a polarizer-free, color-filter-free, and bistable display using a droplet manipulation on a liquid crystal and polymer composite film (LCPCF) is demonstrated. Because of the electrically tunable orientation of the liquid crystal directors anchored among the polymer grains, the wettability of the LCPCF changes with an applied electric field. As a result, we can manipulate a color droplet on LCPCF by distribution of LC directors on LCPCF and then realize a reflective polarizer-free bistable display. The contrast ratio is around 8:1 in a reflective mode.

P-144: A reflective polarizer-free, color-filter-free, and bistable display using a droplet manipulation on a liquid crystal and polymer composite film

Wang Yang Li

Papers

Polarizer-free and fast response microlens arrays using polymer-stabilized blue phase liquid crystals

The dynamics of human sperm droplets on a liquid crystal and polymer composite film

P-144: A reflective polarizer-free, color-filter-free, and bistable display using a droplet manipulation on a liquid crystal and polymer composite film