Quantum dot particles for linearly polarized LCD backlights

Semiconductor quantum dots can provide narrow-band photoluminescence with dominant wavelength determined by the size of the quantum dots. Core-shell particles with an elongated shell that are aligned with each other, can yield linearly polarized red or green light by down-conversion of blue. The shell typically has a larger band gap that effectively absorbs the photons emitted by a blue LED. The electron-hole pair is transferred to the quantum dot core, which has a smaller band gap than the shell. The semiconductor particle with the embedded quantum dot can be aligned by an electric field when it is dispersed in a non-polar solvent or in liquid crystal. After polymerization a thin film is observed with provides linearly polarized light. By aligning this layer with the direction of transmission of the polarizer of an LCD panel, the losses in the polarizer can be reduced considerably. Based on this approach an LCD with highly saturated red and blue colors and low losses in the polarizers should become a possibility

Hybrid fluorescent layer emitting polarized light

Semiconductor nanorods have anisotropic absorption and emission properties. In this work a hybrid luminescent layer is produced based on a mixture of CdSe/CdS nanorods dispersed in a liquid crystal that is aligned by an electric field and polymerized by UV illumination. The film emits light with polarization ratio 0.6 (polarization contrast 4:1). Clusters of nanorods in liquid crystal can be avoided by applying an AC electric field with sufficient amplitude. This method can be made compatible with large-scale processing on flexible transparent substrates. Thin polarized light emitters can be used in LCD backlights or solar concentrators to increase the efficiency

LED backlight designs with the flow-line method

An LED backlight has been designed using the flow-line design method. This method allows a very efficient control of the light extraction. The light is confined inside the guide by total internal reflection, being extracted only by specially calculated surfaces: the ejectors. Backlight designs presented here have a total optical efficiency of up to 80% (including Fresnel and absorption losses) with an FWHM below 30 degrees. The experimental results of the first prototype are shown

Current screens

The architecture of screen design, including LCD, LED and DLP projection, is analysed in terms of the political economy and their aesthetics and phenomenological impacts, in association with the use of codecs as constraining as well as enabling tools in the control and management of visual data transmission

Use of video technology to enhance telemedicine applications

Telemedicine uses information and communication technologies (ICT) to deliver healthcare services remotely, thus removing geographical barriers. Video technology can effectively facilitate the growth of telemedicine. This paper discusses the applications of video technology to enhance telemedicine services. The general functions of telemedicine videoconferencing systems are reviewed. The display technology is also discussed. It is expected that advanced monitors with 8K resolution can be used in future telemedicine videoconferencing systems to significantly improve the image quality and service performance

Tensor displays: compressive light field synthesis using multilayer displays with directional backlighting

We introduce tensor displays: a family of compressive light field displays comprising all architectures employing a stack of time-multiplexed, light-attenuating layers illuminated by uniform or directional backlighting (i.e., any low-resolution light field emitter). We show that the light field emitted by an N-layer, M-frame tensor display can be represented by an Nth-order, rank-M tensor. Using this representation we introduce a unified optimization framework, based on nonnegative tensor factorization (NTF), encompassing all tensor display architectures. This framework is the first to allow joint multilayer, multiframe light field decompositions, significantly reducing artifacts observed with prior multilayer-only and multiframe-only decompositions; it is also the first optimization method for designs combining multiple layers with directional backlighting. We verify the benefits and limitations of tensor displays by constructing a prototype using modified LCD panels and a custom integral imaging backlight. Our efficient, GPU-based NTF implementation enables interactive applications. Through simulations and experiments we show that tensor displays reveal practical architectures with greater depths of field, wider fields of view, and thinner form factors, compared to prior automultiscopic displays.United States. Defense Advanced Research Projects Agency (DARPA SCENICC program)National Science Foundation (U.S.) (NSF Grant IIS-1116452)United States. Defense Advanced Research Projects Agency (DARPA MOSAIC program)United States. Defense Advanced Research Projects Agency (DARPA Young Faculty Award)Alfred P. Sloan Foundation (Fellowship