Technical evolution of liquid crystal displays

Liquid crystal displays (LCDs) have evolved rapidly as a result of fierce competition among the various LCD technologies, and now occupy the largest proportion of the entire display market. The evolution of LCDs continues, with new technologies and new materials in development to replace current devices. This review summarizes the key technologies used in commercially successful LCD products, focusing on the requirements for high-end displays and the benefits of the in-plane switching and multi-domain vertical alignment modes. As in past advances, the development of new materials will play an important role in the continued technical evolution of LCDs.open252

Luminescence in sulfides : a rich history and a bright future

Sulfide-based luminescent materials have attracted a lot of attention for a wide range of photo-, cathodo- and electroluminescent applications. Upon doping with Ce3+ and Eu2+, the luminescence can be varied over the entire visible region by appropriately choosing the composition of the sulfide host. Main application areas are flat panel displays based on thin film electroluminescence, field emission displays and ZnS-based powder electroluminescence for backlights. For these applications, special attention is given to BaAl2S4:Eu, ZnS:Mn and ZnS:Cu. Recently, sulfide materials have regained interest due to their ability (in contrast to oxide materials) to provide a broad band, Eu2+-based red emission for use as a color conversion material in white-light emitting diodes (LEDs). The potential application of rare-earth doped binary alkaline-earth sulfides, like CaS and SrS, thiogallates, thioaluminates and thiosilicates as conversion phosphors is discussed. Finally, this review concludes with the size-dependent luminescence in intrinsic colloidal quantum dots like PbS and CdS, and with the luminescence in doped nanoparticles

Bioengineered Textiles and Nonwovens – the convergence of bio-miniaturisation and electroactive conductive polymers for assistive healthcare, portable power and design-led wearable technology

Today, there is an opportunity to bring together creative design activities to exploit the responsive and adaptive ‘smart’ materials that are a result of rapid development in electro, photo active polymers or OFEDs (organic thin film electronic devices), bio-responsive hydrogels, integrated into MEMS/NEMS devices and systems respectively. Some of these integrated systems are summarised in this paper, highlighting their use to create enhanced functionality in textiles, fabrics and non-woven large area thin films. By understanding the characteristics and properties of OFEDs and bio polymers and how they can be transformed into implementable physical forms, innovative products and services can be developed, with wide implications. The paper outlines some of these opportunities and applications, in particular, an ambient living platform, dealing with human centred needs, of people at work, people at home and people at play. The innovative design affords the accelerated development of intelligent materials (interactive, responsive and adaptive) for a new product & service design landscape, encompassing assistive healthcare (smart bandages and digital theranostics), ambient living, renewable energy (organic PV and solar textiles), interactive consumer products, interactive personal & beauty care (e-Scent) and a more intelligent built environment

Strain relaxation in InGaN/GaN micro-pillars evidenced by high resolution cathodoluminescence hyperspectral imaging

A size-dependent strain relaxation and its effects on the optical properties of InGaN/GaN multiple quantum wells (QWs) in micro-pillars have been investigated through a combination of high spatial resolution cathodoluminescence (CL) hyperspectral imaging and numerical modeling. The pillars have diameters (d) ranging from 2 to 150 μm and were fabricated from a III-nitride light-emitting diode (LED) structure optimized for yellow-green emission at ∼560 nm. The CL mapping enables us to investigate strain relaxation in these pillars on a sub-micron scale and to confirm for the first time that a narrow (≤2 μm) edge blue-shift occurs even for the large InGaN/GaN pillars (d > 10 μm). The observed maximum blue-shift at the pillar edge exceeds 7 nm with respect to the pillar centre for the pillars with diameters in the 2–16 μm range. For the smallest pillar (d = 2 μm), the total blue-shift at the edge is 17.5 nm including an 8.2 nm “global” blue-shift at the pillar centre in comparison with the unetched wafer. By using a finite element method with a boundary condition taking account of a strained GaN buffer layer which was neglected in previous simulation works, the strain distribution in the QWs of these pillars was simulated as a function of pillar diameter. The blue-shift in the QWs emission wavelength was then calculated from the strain-dependent changes in piezoelectric field, and the consequent modification of transition energy in the QWs. The simulation and experimental results agree well, confirming the necessity for considering the strained buffer layer in the strain simulation. These results provide not only significant insights into the mechanism of strain relaxation in these micro-pillars but also practical guidance for design of micro/nano LEDs

Roadmap on structured light

Structured light refers to the generation and application of custom light fields. As the tools and technology to create and detect structured light have evolved, steadily the applications have begun to emerge. This roadmap touches on the key fields within structured light from the perspective of experts in those areas, providing insight into the current state and the challenges their respective fields face. Collectively the roadmap outlines the venerable nature of structured light research and the exciting prospects for the future that are yet to be realized.Peer ReviewedPostprint (published version

Digital Color Imaging

This paper surveys current technology and research in the area of digital color imaging. In order to establish the background and lay down terminology, fundamental concepts of color perception and measurement are first presented us-ing vector-space notation and terminology. Present-day color recording and reproduction systems are reviewed along with the common mathematical models used for representing these devices. Algorithms for processing color images for display and communication are surveyed, and a forecast of research trends is attempted. An extensive bibliography is provided

OLEDs AND E-PAPER. Disruptive Potential for the European Display Industry

DG ENTR and JRC/IPTS of the European Commission have launched a series of studies to analyse prospects of success for European ICT industries with respect to emerging technologies. This report concerns display technologies (Organic Light Emitting Diodes and Electronic Paper - or OLEDs and e-paper for short). It assesses whether these technologies could be disruptive, and how well placed EU firms would be to take advantage of this disruption In general, displays are an increasingly important segment of the ICT sector. Since the 1990s and following the introduction of flat panel displays (FPDs), the global display industry has grown dramatically. The market is now (2009) worth about ¿ 100 billion. Geo-politically, the industry is dominated by Asian suppliers, with European companies relegated to a few vertical niches and parts of the value chain (e.g. research, supply of material and equipment). However, a number of new technologies are entering the market, e.g. OLEDs and electronic paper. Such emerging technologies may provide an opportunity for European enterprises to (re-)enter or strengthen their competitive position. OLEDs are composed of polymers that emit light when a current is passed through them. E-paper, on the other hand, is a portable, reusable storage and display medium, typically thin and flexible. Both OLEDs and e-paper have the potential to disrupt the existing displays market, but it is still too soon to say with certainty whether this will occur and when. Success for OLEDs depends on two key technical advances: first, the operating lifetime, and second, the production process. E-paper has a highly disruptive potential since it opens the door to new applications, largely text-based, not just in ICTs but also in consumer goods, pictures and advertising that could use its key properties. It could also displace display technologies that offer text-reading functions in ICT terminals such as tablet notebooks. There are three discrete segments in the OLED value chain where any discontinuity could offer EU firms the opportunity to play a more significant part in the displays sector: (1) original R&D and IPR for devices and for the manufacturing process and material supply/verification; (2) bulk materials for manufacture and glass; and (3) process equipment:. For the e-paper value chain, we can see that the entry of EU suppliers is perhaps possible across more value chain segments than for OLEDs. Apart from the ones mentioned for OLEDs, there are opportunities to enter into complete devices and content provision. In terms of vertical segments, the point of entry in OLED FPDs for Europe is most likely to be in the mass production of smaller FPDs for mobile handsets. In conclusion, OLEDs and e-paper have the potential to disrupt current displays market and in so doing they may enable EU companies to enter at selected points in the value chain to compete with the Asian ICT industry.JRC.J.4-Information Societ