Search

This Editorial introduces a Special Issue of papers from the SEE International Conference RADAR 2019, which took place in Toulon, France, 23–27 September 2019. The papers are expanded versions of ones that were judged in the reviewing process to be of the highest quality and relevance. Benefitting from the unique location of the conference centre on the French Riviera, the conference was given the theme ‘Sensing from sea to space’, attracting nearly 400 attendees from 26 countries from all over the world (Figure 1). Engineers and researchers coming from private or public sector (universities and laboratories) shared their knowledge and experience on radar topics of common interests from physics to signal processing, from sensor validation to system design, and also on emerging technologies based on artificial intelligence; all topics being supported by 200 papers presented either in oral (150 papers in 36 sessions), or poster sessions (50 papers). Figure 2 shows the range of topics of the papers. 1 FIGURE Conference attendees by country 2 FIGURE Conference paper topics

Herein, a fully paper‐based all‐solid‐state supercapacitor with functionalized cellulose paper as electrodes, carboxymethyl cellulose gel as solid electrolyte and cellulose paper as separator was fabricated. The electrode was fabricated by a conventional papermaking process with silver‐modified fibers and graphene oxide (GO)‐modified fibers followed by reduction of GO. The Ag‐modified fibers and GO‐modified fibers were obtained by in situ growth of Ag nanoparticles and self‐assembly of GO sheets on cellulose fibers, respectively. Ag‐modified fibers act as a flexible current collector with rich three‐dimensional interconnected electron transport pathways to make the reduced GO‐modified fibers as electrode materials to achieve high conductivity (1.93 Ω sq−1) and high‐rate capability. Simple drying can reduce 40% weight of the supercapacitor to facilitate transportation and storage, and its capacitance efficiency can be recovered by wetting when needed. This work opens up a new way of developing cheap, green and high performance full‐paper flexible electronics by conventional papermaking process.

Two-dimensional (2D) transition metal carbides and carbonitrides, called MXenes, with metallic conductivity and hydrophilic surfaces, show great promise as electrode materials for supercapacitors. ...

This study sought to verify the readability of e-paper devices under various conditions. The experimental conditions included various stages of illuminance, different font sizes, and different contrasts. More than 100 participants participated in the experiments from the young to the elderly. The subjects read and compared the e-paper, backlit LCD, and conventional paper under the various conditions.

Similar to the paper-making process, the efficient flame retardant graphene paper is conveniently obtained by using graphene oxide (GO) and hexachlorocyclotriphosphazene (HCCP) aqueous pulp. The “paper pulp” can also conceivably be used as ink to make other hydrophilic films become flame retardant paper. Further, the as-prepared reduced GO-HCCP paper (RGO-HCCP paper), compared with GO-HCCP paper, can maintain its intact structure for a longer time in an ethanol flame. As a consequence of these preparation methods, the bearing temperature of the as-prepared graphene papers shows a significant increase.

The commercialization of electronic paper displays has brought the consumer a truly comfortable and mobile viewing experience, even in bright daylight conditions. We review the display standards activities that support the quality manufacturing of these products and helps drive their market expansion.

Previous studies showed that the use of haptic feedback can improve user’s experience. However, quantitative data on driver performance are missing. This paper examines potential benefits of various feedbacks on driving performance and user’s preference: Visual feedback M, Visual and Auditory feedback (VA), and Visual, Auditory and Haptic feedback (VAH). 24 participants completed a dual-task approach, using the Lane Change Test (LCT) as a driving task and two use cases of touchscreen tasks (Slide or Push task). Moreover, in a given condition participants had to performed a third task to increase mental workload. Results showed that the presence of the trimodal feedback VAH significantly improved driving performances compared to other feedbacks. This was observed through a decrease in standard deviations of lateral. Haptic feedbacks reduce error rates in the dual-task, and that participants significantly preferred this trimodal haptic feedback Therefore, haptic feedback use have an objective positive effect on driver performance and on subjective user’s experience while interacting with a touchscreen interface for both Slide and Push tasks conditions.

This paper collates design concepts of low-power gate driver circuits, and our related work is reviewed. Many approaches to power consumption amelioration have been developed and focus on different parts of circuit structures. Recently, low-frequency clock signals are adopted to further reduce both power consumption and thin-film transistor (TFT) threshold voltage shifts (ΔVTH).

A ‘green’ paper-based flexible room-temperature electronic sensor is assembled from environmentally friendly 3D porous cellulose papers with the filtration coating of hierarchical polyaniline/reduced graphene oxide (PANI/RGO) nanocomposite network, which is prepared by in situ PANI polymerization in RGO solution. The environmentally friendly paper with flexibility, porous structure, portability, and recyclability, is considered as potential substrates for the flexible electronic sensors. The as-assembled flexible electronic gas sensor reveals excellent sensing performance and reliable flexibility without obvious performance change after 1000 bending/extending cycles. The high gas sensing performance could be attributed to synergistic advantages of RGO and PANI, high specific surface area (48.532 m2/g) for efficient adsorption/desorption of vapor analytes, the interconnected nanocomposite sensing network, and the effectively exposed active surfaces. It is anticipated to be extended for fabricating flexible sensors, providing high sensing performance, superior recyclability, robust flexibility and reliable portability to be potentially integrated into handheld flexible electronics.

This paper describes a new e-paper system, which is suitable for office applications. As a replacement of paper based work, it is necessary to have the same readability as paper, capability of handwriting, and convenience of IT equipment. In order to satisfy these requirements, there are three main features of this system. One is a high resolution electrophoretic display (EPD) which provides printed paper image quality. Another is binary display driving which provides high speed image writing on a high resolution display. The last is an original EPD control scheme which gives quick page turning or handwriting performance.

Solid-state lighting has enabled configurable and tunable white-light sources. The available specification criteria, such as CCT, ΔuV, and CRI, are insufficient to characterize the color quality properties for these emerging technologies. An overview of new characterization methods will be presented with their potential for successful adoption by the lighting industry.

High pixel per inch (PPI) and high resolution micro-LED (μLED) displays are attracting more and more attentions. The increasing pixel number requires a large amount of bonding pads and brings huge difficulties to micro-LED system design and lowers power efficiency as well. It is urgent to integrate row and column driving circuits onto the micro-LED panel. Here we report a fully integrated active matrix programmable micro-LED system on panel (SoP) with ultraviolent (UV) and blue emission wavelengths. The micro-LED SoP has a resolution of 60x60 and pixel pitch of 70μm. The micro-LED SoP was achieved by integrating micro-LED arrays with silicon-based PMOS driving panel using fine-toned flip-chip bonding technology. With fully integrated scan and data circuits, the number of bonding pads was greatly reduced from 136 to 28 and large amount of metal interconnection lines were saved. The micro-LED SoP panel was mounted on a periphery driving board and representative characters were displayed successfully.

A 3D Stereoscopic Head-Up Display (HUD) using a tunable bandpass filter to perform left and right image spectral separation is presented. Using a single filter reduces the size and the cost of the HUD optical engine, and enables each spectral band to be accurately tuned. Experiments performed on the first prototype demonstrates the ability to continuously tune the bandpass frequency on 30 nm range while keeping a 20 nm bandwidth. Such a system avoids the use of a bulky and costly rotating wheel and enables the use of Holographic Optical Elements known to be wavelength selective.

UDC is the pioneer in the development and supply of phosphorescent OLED technology and materials for both display and lighting applications. In this presentation we outline the status and opportunities for PHOLED lighting technology. We will review how OLED lighting fits in the lighting ecosystem and its prospects for the next few years.

Electrically tunable lens power of liquid crystal (LC) lenses attracts many applications. The basic mechanism, structures, and development of LC lenses are reviewed. How LC lenses assist in registration of images and vision correction in augmented reality is discussed.

We propose a novel pixel circuit using source-follower structure to be independent of frequency effect of blue-phase liquid crystal displays (BPLCDs). Simulation results indicated that required gray-level-voltages across the BPLC could be achieved accurately when a proper threshold voltage of the driving TFT was chosen. We also successfully fabricated a 12.7-inch prototype BPLCD using the proposed pixel circuit driven with a field-sequential-color method of 240 Hz.

The capacitively-coupled wireless power transmitting system which provides a wide power-supply position was developed to realize a battery-less electronic paper. The high frequency, 13.56 MHz, was employed and the frequency was modulated to keep the resonant conditions. The special electrode configuration and circuit to suppress EMI were revealed.

Electronic paper devices based on electrophoretic layers are now predominantly limited to greyscale reproduction of (semi)static information. This has been acceptable in the past, but the near future will require color, with ever more and better colors. The final goal is a color image that challenges the performance of a color photograph. This paper describes the results of a first prototype electro-osmotic color display capable of achieving this, opening the route to bright, full color displays compatible with existing LCD infrastructure.

Ever since Emmett Leith and Juris Upatnieks were able to show the world's first true hologram of a steam locomotive people have imagined being able to generate dynamic holographic displays. While fully dynamic 3D holographic displays still present significant challenges, Daqri Holographics has developed a revolutionary phase only holographic display technology that is a compelling solution for many applications. Developing a dynamic holographic display presents a significant challenge, however its application to automotive products with their exacting quality requirements introduces additional and significant challenges. These have been overcome and a head up display based on this technology is now in production. This paper will look at the principles and benefits of utilising phase holographic displays in head up display applications and will discuss some of the challenges that had to be overcome.

Retinal Imaging Laser Eyewear has a miniature laser projector inside the frame which provides the wearer with digital image information through the pupil using the retina as a screen. This compact universal-design eyewear features focus-free and augmented-reality image independent of the wearers' visual acuity and point of focus. This paper describes the background of this technology, the principle of focus-free imaging, the device with a trademark of RETISSA®, and its laser safety analyses based on international guidelines and standards.

As advanced driving assistance systems pervade automobiles, drivers are exposed to more information than ever. Head up displays are expected to provide necessary contents depending on necessity and urgency. In this paper, the authors discuss and overview the promises and challenges of the technology.

In this paper, various integration schemes for in-cell capacitive touch panels will be reviewed. Continuous efforts have been made to eliminate the interference between display and touch sensor structure. A in-cell LCD module with self-capacitance touch sensor integrated will be presented.

The stroboscopic effect is one of the most visible artifact of temporally modulated light, which exists even at relatively high frequencies. It especially becomes apparent with LED lighting, because of its fast temporal response to changes in the driving signal. This paper describes a method to measure the visibility of the stroboscopic effect, and discusses the impact of frequency, duty cycle, wave shape and intensity. All experimental results are combined to define a measure that accurately predicts the visibility of the stroboscopic effect based on the weighted summation of the energy in different frequency components of the driving signal. This measure can be used by industry to improve the perceived quality of LED lighting systems.

Next generation automotive head-up display (HUD) could fundamentally change how OEMs utilize a HUD. A significantly larger virtual display area and vastly improved image quality are two of the many benefits. Along with the benefits come a unique set of challenges, which can be addressed by incorporating TI DLP® product solutions. This paper explores options for these challenges, including a comparison of different solid state illumination sources, and offers practical solutions for developers.

This paper reviews the tradeoffs that should be considered when designing a micro-display based, direct-view near-eye displays. It reviews available display technologies, and discusses how eye-piece focal length relates to field of view and usable eye relief. It concludes with 3 examples of direct view eyepiece designs.

Augmented reality technologies such as head-up display are significant and useful for not only an automotive application, but also medical applications, and therefore we have developed several technologies, i.e., the head dome projector, monocular head-up display. We also introduce our latest development, that is, the head-up display for the magnetic resonance imaging system to reduce the patients' anxiety during the examination.

A universal column driver is implemented in a 0.13-µm highvoltage CMOS process for not only TFT-LCD but also OLED applications. The proposed column driver employs 13-bit linear DAC to cover all gamma curves of display applications and address-based configuration for intra- panel interface protocol to support both TV and IT applications. Measured results demonstrate the average voltage of output channels (AVO) is under 1mv, which satisfies 1-LSB resolution at 18.5V of AVDD.

The emergence of ILED Displays (also termed MicroLED Display) has the potential to be a true 4th Gen flat display technology by superseding Plasma, LCD and OLED technologies. They offer significant increase in power efficiency, brightness with reduced cost. The use of inorganic LEDs largely removes the challenge of lifetime and sealing which, until recently, has curtailed the wide adoption of OLED display. While ILED Display technology offers a range of benefits, there remain a number of issues to be addressed before this new display technology can achieve market acceptance. InfiniLED introduces the technology, discusses some of the performance characteristics and presents its practical approach to commercializing this technology.

With LED and OLED taking over the general lighting market, and OLED being the most promising successor technology to LCD with whatever backlight source, both areas have begun to converge. This leads to completely new ways of building and controlling general lighting systems, but also to the possibility (and necessity) to rethink the currently mostly disjunct roles of general lighting and information displays. In the article, we will discuss some of these new possibilities, as well as some of the implications coming with those.

Porous bioactive glass (BaG) structures were manufactured applying novel preceramic paper process. Preceramic papers were produced for aqueous suspensions loaded with different contents of pulp fiber and BaG filler. Pressure loading was applied in order to increase the packing density in the paper sheets. The paper sheets were sintered at 630 °C for 1 h. The porous glass–ceramic specimens were characterized for density, porosity, composition, microstructure, and mechanical properties. A pronounced volumetric shrinkage was observed, but no surface flaws or inhomogeneous areas were detected. The mechanical strength using the ball on three balls test and elastic modulus of sintered specimens vary between 21 and 33 MPa and 0.30–0.85 GPa, respectively.

We propose an advanced in-cell touch (AIT) sensor integrated on TFT substrate. The proposed touch sensor perceives selfcapacitance formed between touching object and sensing electrode which is made by common electrode of AH-IPS panel. This new touch sensor shows above 50dB-signal-to-noise ratio and multi-touch function without loss of transmittance. Finally we have succeeded in in-cell touch panel development of 15.6” FHD for notebook PC and 7” WVGA for automotive which supports 2mm-thick glove touch.

For mobile satellite communications applications such as the connected car, a scanning antenna is required. Kymeta has developed a novel, electronically scanned antenna technology achieved through the use of high-birefringence liquid crystals. Kymeta's technology is positioned for mass production by leveraging the manufacturing capabilities of the LC display industry.

Light field capture and display technologies have been rapidly emerging in the past decade. The high dimensional design space of light field systems, however, imposes new challenges for end to end system design and evaluation. We discuss design principles for task specific light field camera systems and outline how such principles can be applied to or need to be modified for the design of personal light field displays.

We have developed a new stylish TFT-LCD. We located gatedriver monolithic circuits in the pixel area. As there are no electronic circuits in the frame area, we can realize a narrow border and round corners or a multi-concave shape, and the frame shape can be easily revised.

We have successfully developed an 8K display with 120Hz frame rate, 12bit each RGB. The wide gamut has been expanded over 85% coverage ratio of ITU-R BT2020. Furthermore, the input interface has been upgraded to single optical fiber cable of 256Gbps which is capable to transmit 8K/120Hz video.

We developed the world's highest resolution panel (2250ppi, 1.96 "UHD) with glass-based process technology. A new pixel design and architecture has been devised to integrate TFT, contact hole, and data / gate lines in a small pixel pitch. A small TFT has been implemented and an extreme process has been developed. These technologies are expected to be applied mainly to VR, AR and Hologram platform.

We have developed a thin and flexible smart card with EPD Electronic Paper Display using QR-LPD™ Quick-Response Liquid Powder Display technology. The extremely low energy consumption display applications can be realized by utilizing the image holding property with no energy consumption. In this study, we combined flexible EPD with wireless energy and data transfer system in order to realize extremely thin, light weight and flexible smart card that has dot matrix EPD. The possibility of wireless smart card with flexible EPD using QR-LPD technology is discussed.

In recent years, e-readers have spread to many countries. Most of e-readers have a reflective type of display called e-paper. The general view is that under conditions of low illuminance, readability of the e-paper display is poor. However, most recent e-readers have a built-in light system. This system would improve the readability of the e-paper display under low illuminance conditions. We carried out experiments to evaluate the readability e-paper devices using different systems. In the experiments, we conducted subjective evaluations under staged illuminance conditions by using English words. This study found that e-paper devices with built-in light under low illuminance condition were superior in terms of readability.

The thin and flexible LSI driver with a thickness of less than 40μm for passive-matrix driven Quick-Response Liquid Powder Display (QR-LPD™) was successfully mounted onto the flexible printed circuit (FPC). The mounted LSI on the plastic substrate shows no significant degradation in the driving performances and keeps physical flexibility without any failures of connection. This technology can realize the fully flexible electronic paper in combination with a plastic substrate QR-LPD™ fabricated by roll-to-roll process.

This paper presents an UHD Active Barrier auto stereoscopic 3D module, including its base panel, 3D technology, 3D design, structure, and performance estimation. In order to achieve an optimized 3D image, two kinds of 3D mapping designs were compared. With the different module structure, different manufacture process was also studied, especially how the alignment accuracy between base panel and Active barrier affect the 3D image quality. Finally, the UHD Active Barrier 3D module was estimated to ensure it has the potential for home application.

Assuming large color gamut and therefore better color reproducibility will be a highly desired feature of all displays as we look to the near future, we make the case in this paper that Quantum Dots (QDs) are currently the down-conversion technology of choice that will allow liquid crystal display (LCD) makers to cost-effectively reach and exceed 100% of the NTSC (National Television Standard Committee) standard while achieving maximum system efficiency. We will discuss in detail the numerous fundamental advantages of QDs over phosphors, along with their scientific origins, and make the case that QDs are the ultimate light generating material for next-generation displays.

Efficacious white OLED devices have been developed for lighting applications. The high efficacy was achieved by incorporating two key technologies: a 3-unit tandem hybrid device architecture and a random scattering light extraction enhancement structure. The light extraction enhancement structure was used for both external (EES) and internal (IES) applications. Laboratory results showed an EES device with 73.6 lm/W efficacy and an IES device with 111.7 lm/W efficacy. The 3-unit tandem structure and EES were also applied to production line devices and achieved over 80 lm/W efficacy at 1000 cd/m2 and over 60 lm/W at 3000 cd/m2.

Projected capacitive (p-cap) touch technology now dominates the consumer-electronics touch market, but many different touch technologies still compete in the commercial touch applications. Why is this so? Will it continue? While p-cap market share will continue to grow, this objective analysis supports the view that diverse requirements in commercial-touch applications will maintain touch ‘biodiversity‘.

A novel directional backlight system for transmissive LCD illumination is described for the first time. By controlling the angular light distribution from the display, very low power consumption can be achieved for a required display luminance, or the backlight can operate with a conventional luminance distribution. Additionally very high display luminance can be achieved at the same power consumption levels as conventional backlight designs. Such a display can achieve good readability in high illuminance conditions, for example in direct sunlight. The backlight optical stack comprises a stepped waveguide Directional Light Guide Plate (D-LGP), a micro-structured reflective film and a polarisation recirculation structure that cooperates with an LED array to direct viewing windows to an observer with high coupling efficiency. The system implementation is described and measured performance from demonstrator displays is presented.

Quantum dot technology offers the promise of efficient and relatively inexpensive liquid crystal displays (LCDs) with large color gamuts (∼115% NTSC u'v'). Now, for the first time, a variety of high color performance devices are on the immediate horizon for applications ranging from 3“ diagonal hand held smart phones to +85” diagonal TVs . While people clearly prefer color displays, the relative value of different color reproduction systems remains an open question. Here we review how quantum dots enable high color performance and some of the advantages of large color gamut displays.