Patterned Liquid Crystal Devices for Near-eye Displays

As a promising next-generation display, augmented reality (AR) and virtual reality (VR) have shown attractive features and attracted broad interests from both academia and industry. Currently, these near-eye displays (NEDs) have enabled numerous applications, ranging from education, medical, entertainment, to engineering, with the help of compact and functional patterned liquid crystal (LC) devices. The interplay between LC patterns and NEDs stimulates the development of novel LC devices with unique surface alignments and volume structures, which in turn feedback to achieve more compact and versatile NEDs. This dissertation will focus on the patterned LC with applications in NEDs. Firstly, we propose and explain the working principles and generation of novel patterned LC devices, including LC configurations, surface alignment mechanism, polarization field generation, and fabrication process. Secondly, we theoretically analyze the optical properties of patterned LC devices, providing the optical efficiency, devices thickness, polarization selectivity, wavelength, and angular bandwidth. Based on the dimensions of the surface pattern, the LC devices can be divided into reflector, grating, and lens, respectively. Finally, we focus on the applications of these novel patterned LC devices to address some challenges in current NEDs. More specifically, achieving a high-resolution density in NEDs, especially for VR systems is an urgent issue. To enhance the resolution without introducing any extra burden to the system, we propose an elegant method with the combination of foveated view and polarization multiplexing, based on LC reflector. For LC grating, it shows a nearly 100% efficiency with a large diffraction angle, which is a perfect candidate for the waveguide-based AR systems. We propose and demonstrate the LC grating-based waveguide AR with benchtop demo and further performance optimization. For LC lens, it can achieve controllable power and large off-axis angle while maintaining high efficiency. These unique and attractive features give LC lenses the ability to achieve a glasses-like AR architecture while maintaining high optical efficiency. Based on this LC lens, we demonstrate a novel AR system design using polarization and time multiplexing methods to simultaneously obtain a double field of view and a glasses-like form factor. The proposed patterned LC devices for NED applications are validated by both optical simulation and experiment. Multiple tabletop demos are constructed to illustrate how these patterned LC devices can significantly improve the visual experiences of these next-generation NEDs

Business Case and Technology Analysis for 5G Low Latency Applications

A large number of new consumer and industrial applications are likely to change the classic operator's business models and provide a wide range of new markets to enter. This article analyses the most relevant 5G use cases that require ultra-low latency, from both technical and business perspectives. Low latency services pose challenging requirements to the network, and to fulfill them operators need to invest in costly changes in their network. In this sense, it is not clear whether such investments are going to be amortized with these new business models. In light of this, specific applications and requirements are described and the potential market benefits for operators are analysed. Conclusions show that operators have clear opportunities to add value and position themselves strongly with the increasing number of services to be provided by 5G.Comment: 18 pages, 5 figure

Wearable Communications in 5G: Challenges and Enabling Technologies

As wearable devices become more ingrained in our daily lives, traditional communication networks primarily designed for human being-oriented applications are facing tremendous challenges. The upcoming 5G wireless system aims to support unprecedented high capacity, low latency, and massive connectivity. In this article, we evaluate key challenges in wearable communications. A cloud/edge communication architecture that integrates the cloud radio access network, software defined network, device to device communications, and cloud/edge technologies is presented. Computation offloading enabled by this multi-layer communications architecture can offload computation-excessive and latency-stringent applications to nearby devices through device to device communications or to nearby edge nodes through cellular or other wireless technologies. Critical issues faced by wearable communications such as short battery life, limited computing capability, and stringent latency can be greatly alleviated by this cloud/edge architecture. Together with the presented architecture, current transmission and networking technologies, including non-orthogonal multiple access, mobile edge computing, and energy harvesting, can greatly enhance the performance of wearable communication in terms of spectral efficiency, energy efficiency, latency, and connectivity.Comment: This work has been accepted by IEEE Vehicular Technology Magazin

The Detection of Ionizing Radiation by Plasma Panel Sensors: Cosmic Muons, Ion Beams and Cancer Therapy

The plasma panel sensor is an ionizing photon and particle radiation detector derived from PDP technology with high gain and nanosecond response. Experimental results in detecting cosmic ray muons and beta particles from radioactive sources are described along with applications including high energy and nuclear physics, homeland security and cancer therapeuticsComment: Presented at SID Symposium, June 201