Switchable Lens Research Articles

Viewing experiences of two-dimensional photos and textual content on autostereoscopic three-dimensional displays

We examined the image quality, image clarity, and viewing comfort of 2-D images rendered on an autostereoscopic display. Opinions on daily use of the content was gathered. Two different stereo displays were used in the experiments-a lenticular lens stereo display employing fixed 3-D stereo and a display with a switchable lenticular lens structure. Images were rendered on the displays with three different rendering schemes. Photos of natural scenes, artificial content, and content containing textual elements were used as the test stimuli. When images with natural scenes or artificial content were categorized into clusters according to the amount of details, significant differences in image quality, image clarity, and viewing comfort scores were observed. When two of the schemes were compared using the images containing textual elements, a significant difference in the viewing comfort and a significant increase in perceived stereoscopic depth impression were found with one of the schemes. Furthermore, image quality and viewing comfort were better with the 2-D display mode than with the 3-D mode. The use of the 2-D text content in the 3-D display mode seemed to be acceptable in general, but for longer term and repeated use, improvements in text quality should be considered. The results indicate that an increase in detail levels may decrease the evaluated image quality, clarity, and viewing comfort. Moreover, for all experimental conditions, better image quality, increased image clarity, and a more comfortable viewing experience had a positive influence on decisions of daily use.

44.4: Invited Paper: A Novel Stereo Display that Presents Nearly Correct Focus Cues

AbstractStereoscopic displays can produce perceptual distortions, performance decrements, and fatigue/discomfort because of conflicts between the presented binocular disparities and focus cues (blur and accommodation). We have developed a display that circumvents this problem. It uses a fast switchable lens synchronized to the display such that focus cues are nearly correct. We describe its use in an experiment on visual discomfort and fatigue.

Diffraction and properties of holographic polymer dispersed liquid crystal switchable lens

A holographic polymer dispersed liquid crystal （H-PDLC） switchable lens is reported. The diffraction efficiency was analyzed at different phase separation coefficients within the visible band （400—800 nm） with the coupled wave theory for a phase-type H-PDLC switchable lens. In our experiments, the maximum efficency of 70% was achieved. The H-PDLC switchable lens shows excellent imaging performance and fast response.It is potentially useful in many applications, such as optical communications, optical imaging,e.g.,in digital cameras.

High-speed switchable lens enables the development of a volumetric stereoscopic display

Stereoscopic displays present different images to the two eyes and thereby create a compelling three-dimensional (3D) sensation. They are being developed for numerous applications including cinema, television, virtual prototyping, and medical imaging. However, stereoscopic displays cause perceptual distortions, performance decrements, and visual fatigue. These problems occur because some of the presented depth cues (i.e., perspective and binocular disparity) specify the intended 3D scene while focus cues (blur and accommodation) specify the fixed distance of the display itself. We have developed a stereoscopic display that circumvents these problems. It consists of a fast switchable lens synchronized to the display such that focus cues are nearly correct. The system has great potential for both basic vision research and display applications.

Switchable liquid-crystal lens could correct vision

Switchable liquid-crystal lens could correct vision

Color Switchable Goggle Lens Based on Electrochromic Polymer Devices

AbstractWe have developed a set of new electrochromic devices (ECDs) for special application goggles, whose color can be switched between transparent and a specific color mode, i.e. blue (B). This paper will discuss the design, film deposition, device assembly and characterizations of the color switchable lens. The ECD is composed of a layer of thin film conducting polymer poly (3,4-(2,2-dimethylpropylenedioxy)thiophene) (PProDOT-Me2), a layer of thin film inorganic oxide V2O5-TiO2, and a layer of ionic conductive electrolyte. The thin films are electrochemically deposited on ITO coated flexible plastic substrate. The whole device is packaged with an UV cured flexible film sealant. The goggle lens exhibit tuneable shade in visible light wave length (380-800nm), with a maximum contrast ratio at 580nm. Meanwhile, other unique properties include fast switching speed, low driving voltage, memory function (no power needed after switching, bistable), great durability, high flexibility, light weight, and inexpensiveness.

Electro-Optic Adaptive Lens as a New Eyewear

Adaptive lens with the capability of changing the focusing power has important applications in 3D imaging, optical information processing, and ophthalmology. We demonstrate a switchable electroactive lens with very high diffraction efficiencies using a circular array of electrode pattern filled with liquid crystal as the active medium to be used as an adaptive eyewear. Electrically adjustable lens allows the focal length to be voltage controlled without bulky and inefficient mechanical movement. Binary Fresnel zone plates using liquid crystal as active material have been demonstrated for imaging applications, but the diffraction efficiency is low. The lens is flat and the thickness of the liquid crystal is 5 μm. Diffraction efficiencies exceeding 90% has been achieved for an 8-level diffractive lens. The lens can be operated as both positive and negative lens. Design, modeling, fabrication, and characterization of the lens is presented. Using nematic liquid crystal, the lens is polarization dependent and two crossed lenses are integrated to form a complete lens. The ON- and OFF-state of the electrically controlled lens allow near- and distance-vision respectively for presbyopia eyes.

Pancharatnam-Berry phase optical elements for wave front shaping in the visible domain: Switchable helical mode generation

We report the realization of a Pancharatnam-Berry phase optical element [Z. Bomzon, G. Biener, V. Kleiner, and E. Hasman, Opt. Lett. 27, 1141 (2002)], for wave front shaping working in the visible spectral domain, based on patterned liquid crystal technology. This device generates helical modes of visible light with the possibility of electro-optically switching between opposite helicities by controlling the handedness of the input circular polarization. By cascading this approach, fast switching among multiple wave front helicities can be achieved, with potential applications to multistate optical information encoding. The approach demonstrated here can be generalized to other polarization-controlled devices for wave front shaping, such as switchable lenses, beam splitters, and holographic elements.

Ferroelectric nanoparticle/liquid-crystal colloids for display applications

— A non-synthetic approach to modify liquid crystals (LCs) by dispersing low concentrations of ferroelectric nanoparticles is reported. These dilute colloids are stable and appear similar to a pure LC. However, by changing the concentration and the type of ferroelectric particles, the physical properties of the LC materials can be tailored, including the nematic isotropic transition temperature (TNI), the dielectric constants, the birefringence (Δn), elastic constants, and the threshold voltage. Specifically, doping low concentrations of BaTiO3 nanoparticles (∼1%) into a LC MLC-6609 increases TNI up to ∼40°C. This giant shift of TNI has never been previously reported and indicates strong interactions between the LC and ferroelectric nanoparticles on a molecular level. The doped LC also demonstrates significant enhancement in birefringence (by 10–30%), dielectric anisotropy (by ∼50%), and the elastic constant K33 (by ∼20%). Ferroparticles act as molecular additives and modify the intrinsic properties of LC materials without time consuming and expensive chemical synthesis. The new LC materials are very attractive and suitable for use in displays, switchable lenses, beam steering, as well as other light-controlling devices.

8.1: Invited Paper: Achieving Near-Correct Focus Cues in a 3D Display using Multiple Image Planes

Focus cues specify inappropriate 3d scene parameters in conventional displays because the light comes from a single surface, independent of the depth relations in the portrayed scene. We examine the efficacy of a stereo-display prototype designed to minimize these problems by using multiple image planes to present near-correct focus cues. Each eye's view is the sum of several images presented at different focal distances. Variation in focal distance is provided by either multiple beam splitters or by use of a switchable lens. The stimulus to accommodation is more consistent with the portrayed depth than with conventional displays. Compared to a normal, fixed-distance display, observers show improved stereoscopic performance in different psychophysical tasks including speed of fusing stereoscopic images. The multiple image-planes approach provides a practical solution for some shortcomings of conventional displays.

The Commercialization of Plastic Photochromic Lenses: A Tribute to John Crano

With 1999 marking the 100th anniversary of the discovery of organic photochromic compounds1, it is a fitting time to reflect back on commercial uses that have developed from this interesting class of organic compounds over the years. From the many applications that have been proposed, including security devices and optical memory storage, the one application that has achieved substantial commercial success is switchable lenses. Such lenses, based on inorganic photochromes (AgX), have been available since the mid 1960s, but it is only in the last 10 years that organic systems with acceptable performance have been available in the marketplace. From the mid 1980s until his sudden death in early 1998, John Crano lead the research effort at PPG Industries that developed the photochromic systems that have been commercialized by Transitions Optical Inc. under the name Transitions®.

An investigation of patterning anisotropic gels for switchable recordings

A new kind of anisotropic gel has been produced by photopolymerization of liquid crystal (LC) mixtures composed of monoacrylates, diacrylates and non-reactive conventional LC molecules. After polymerization, lightly cross-linked anisotropic polymer networks swollen by the non-reactive molecules are produced. These systems showed a gel-point associated with the onset of the formation of a three dimensional network. Above this point, a rapid increase in the threshold voltage was observed. Various factors, such as the photoinitiator concentration and the monoacrylate and diacrylate concentrations, as well as the intensity of the light used for the polymerization, have a strong influence on the gel-point. The switching kinetics of the materials are also strongly influenced by the aforementioned parameters. Two relaxation processes were found to occur within the gels above the gel-point. Using dielectric spectroscopy, this behaviour was found to be associated with an inhomogeneous phase structure within the gels. Patterned irradiation was used to produce regions with different threshold voltages for switching. In this way, patterns were created in the gels, which become visible, by the application of an electric field. It was demonstrated that this technique can be used to produce switchable gratings, Fresnel lenses, and photographs.

Control optimization of spherical modal liquid crystal lenses

Liquid crystal modal lenses are switchable lenses with a continuous phase variation across the lens. A critical issue for such lenses is the minimization of phase aberrations. In this paper we present results of a simulation of control signals that have a range of harmonics. Experimental results using optimal sinusoidal and rectangular voltages are presented. A lack of uniqueness in the specification of the control voltage parameters is explained. The influence of a variable duty cycle of the control voltage on an adaptive lens is investigated. Finally we present experimental results showing a liquid crystal lens varying its focal length.