18.2: Invited Paper: Flexible eWriter Technology and Applications

Abstract

Reflective cholesteric liquid crystal display based flexible eWriters have remarkable writing feel, are rugged, high contrast, and require very little power to operate. These eWriters are redefining the writing space in this increasingly digital world. Flexible eWriters have been rapidly penetrating the consumer markets and now are poised to add new and unique applications in consumer, education, healthcare, and other fields. These applications and the eWriter technology will be discussed in detail.

Geometrical Optics Analysis of Diffraction in Patterned Cholesteric Liquid Crystals

“…Cholesteric liquid crystals (CLCs) spontaneously form a nanohelical structure, in which the sinusoidal rotation of the CLC directors results in a periodic variation in permittivity. The periodic variation causes Bragg reflection for circularly polarized light with a wavelength similar to the helical pitch length, and because of the polarization selectivity, the reflection band is often referred to as selective reflection. − The selective reflection bandwidth depends on the pitch and birefringence of the CLC and is easily controllable by varying the chiral dopant concentration in the CLC mixture or by applying voltage. , Several applications, such as reflective displays, − circular polarizers, mirrors, and lasers, − have been developed based on selective reflection. Recently, advances in patterned alignment technology have led to the control of the reflected light phase, enabling new diffractive optical components − and optical vortex phase plates. − …”