Foreword. Series Editor's Foreword. Preface. 1. Liquid crystal physics.* Introduction.* Thermodynamics and statistic physics.* Orientational order.* Elastic properties of liquid crystals.* Response of liquid crystals to electro-magnetic fields.* Anchoring effects of nematic liquid crystal at surfaces. 2. Propagation of light in anisotropic optical medium.* Electromagnetic wave.* Polarization.* Propagation of light in uniform anisotropic optical media.* Propagation of light in cholesteric liquid crystals. 3. Optical modeling methods.* Jones matrix method.* Mueller matrix method.* Berreman 4x4 method. 4. Effects of Electric field on Liquid Crystals.* Dielectric interaction.* Flexoelectric Effect.* Ferroelectricity in liquid crystals. 5. Freedericksz transition.* Calculus of variation.* The Fredeericksz transition: statics.* The Freedericksz transition: dynamics. 6. Liquid Crystal Materials.* Introduction.* Refractive indices.* Dielectric constants.* Rotational Viscosity.* Elastic constant.* Figure-of-merits.* Refractive index matching between liquid crystals and polymers. 7. Modeling of liquid crystal director configuration.* Electric energy of liquid crystals.* Modeling electric field.* Simulation of liquid crystal director configuration. 8. Transmissive liquid crystal display.* Introduction.* Twisted nematic cells.* In plane switching (IPS) mode.* Vertical alignment (VA) mode.* Multi-domain Vertical Alignment (MVA) Cells.* Optically compensated bend (OCB) cell. 9. Reflective and Trasreflective display.* Introduction.* Reflective liquid crystal displays.* Transflector.* Classification of Transflective LCDs.* Dual-cell-gap Transflective LCDs.* Single-cell-gap Transflective LCDs.* Performance of transflective LCDs. 10. Liquid crystal display matrices, drive schemes and bistable displays.* Segmented displays.* Passive matrix displays and drive scheme.* Active Matrix Displays.* Bistable ferroelectric liquid crystal displays and drive scheme.* Bistable nematic displays.* Bistable cholesteric reflective display. 11. Liquid crystal/polymer composites. * Introduction.* Phase separation.* Scattering properties of liquid crystal/polymer composites.* Polymer dispersed liquid crystals.* Polymer stabilization liquid crystals.* Displays from liquid crystal/polymer composites. 12. Tunable liquid crystal photonic devices. * Introduction.* Laser beam steering.* Variable Optical Attenuators.* Tunable-Focus Lens.* Polarization-Independent LC Devices. Index.

Fundamentals of Liquid Crystal Devices

This disclosure concerns an interactive head-mounted eyepiece including an optical assembly through which the user views a surrounding environment and displayed content. The displayed content includes a local advertisement, wherein the location of the eyepiece is determined by an integrated location sensor and wherein the local advertisement has a relevance to the location of the eyepiece. The head mounted eyepiece may also include an audio device and the displayed content may comprise local advertisements and audio.

Local advertising content on an interactive head-mounted eyepiece

The history of human civilization is accompanied by the development of novel materials, from the period of natural stone, the bronze and iron age, to the modern times of synthetic materials and promising advanced materials. Liquid crystals (LCs) are one of such kind of materials that greatly infl uence our daily life, and which are not limited to displays such as TVs and personal computers. Being an intermediate phase of matter, LCs show characteristics of both controllable mobility of an isotropic liquid and ordered regularity of a crystalline solid. Combined with their photoresponsive properties, photocontrollable LC actuators have enabled a variety of applications in various fi elds, which include fl at panel displays, photonics, photo-driven devices, and more recently nanotechnology. The LC’s unique features provide soft materials in a liquid-crystalline state with interesting properties such as 1) selfassembly, 2) fl uidity with long-range order, 3) molecular and supramolecular cooperative motion (MCM and SMCM), 4) large birefringence and anisotropy in various physical properties (optical, mechanical, electrical and magnetic), 5) alignment change induced by external fi elds at surfaces and interfaces, and 6) deformation of LC elastomers (LCEs) in response to stimuli. [ 1–4 ]

Photocontrollable liquid-crystalline actuators.

Head-worn adaptive display

An eyepiece includes a mechanical frame adapted to secure a lens and an image source facility above the lens. The image source facility includes an LED, a planar illumination facility and a reflective display. The planar illumination facility converts a light beam from the LED received on a side of the planar illumination facility into a top emitting planar light source, uniformly illuminates the reflective display, and is substantially transmissive to allow reflected light to pass through towards a beam splitter. The beam splitter is positioned to receive the image light and to reflect a portion onto a mirrored surface. The mirrored surface is positioned and shaped to reflect the image light into an eye of a user of the eyepiece thereby providing an image within a field of view, the mirrored surface further adapted to be partially transmissive within an area of image reflectance.

Eyepiece with uniformly illuminated reflective display

Electrically variable gradient index liquid crystal lens is developed that uses flat uniform liquid crystal layer and electrodes. The spatial modulation of the electric field across the lens aperture is obtained by the modulation of the effective dielectric constant of an integrated doublet lens structure. The dielectric constants of two materials, composing the doublet, are chosen to be different at electrical driving frequencies, while their optical refractive indexes are the same, hiding thus the structure from the optical point of view. This “hidden layer” approach decouples the electrical and optical functions of that structure, increases significantly the performance of the lens and enables new functionalities. The technical performance and various driving schemes of the obtained lens are presented and analyzed.

Optical lens with electrically variable focus using an optically hidden dielectric structure

We investigate the electro-optical properties of polymer stabilized nematic liquid crystals produced by in situ photopolymerization technique using Gaussian laser beam. The distribution of refractive index in such structure under the action of a homogeneous electric field reveals a non-homogeneous lens-like character, approximately reproducing the intensity transverse distribution in the photopolymerizing beam.

Polymer-stabilized liquid crystal for tunable microlens applications

We create planar-periodic alignment in nematic liquid crystal (LC) cell by using a command layer of azo-dye molecules directly deposited on the cell substrates and exposed with two interfering laser beams of opposite circular polarizations. Permanent high efficiency polarization gratings are thus created. The diffraction efficiency of those gratings is controlled by a uniform electric field applied across the cell. The electro-optical properties of such polarization gratings are studied. Obtained gratings can be used for electrically controlled discrimination and detection of polarized components of light.

Optical polarization grating induced liquid crystal micro-structure using azo-dye command layer.

Variable liquid crystal devices for controlling the propagation of light through a liquid crystal layer use a frequency dependent material to dynamically reconfigure effective electrode structures in the device The drive signal source uses pulse-width modulation to set a frequency and an amplitude of the drive signal

Electro-optical devices using dynamic reconfiguration of effective electrode structures

Methods are provided for wafer scale manufacturing camera modules without adjustment components to compensate for assembly errors and optical errors incurred within manufacturing tolerances. Camera modules are assembled in wafer arrays from arrays of image sensors, arrays of lens structures and arrays of optical trim elements. At least one of the arrays is a wafer. Lens structures are configured to provide less optical power than necessary to focus an image at infinity on image sensors without trim elements. A test performed during the wafer scale assembly of camera modules, after at least the sensor array and the lens structure array assembled, determines optical errors by identifying optical distortions and aberrations quantified in terms of optical power, astigmatism, coma, optical axis shift and optical axis reorientation deficiencies. Corresponding trim elements are configured to counteract distortions and aberrations prior to singulating useful camera modules from the array.

Karen Asatryan

Papers

Optical lens with electrically variable focus using an optically hidden dielectric structure

Polymer-stabilized liquid crystal for tunable microlens applications

Optical polarization grating induced liquid crystal micro-structure using azo-dye command layer.

Electro-optical devices using dynamic reconfiguration of effective electrode structures

Methods of adjustment free manufacture of focus free camera modules