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This paper reviews the development of new high-temperature polymeric materials applicable to plastic substrates in image display devices with a focus on our previous results. Novel solution-processable colorless polyimides (PIs) with ultra-low linear coefficients of thermal expansion (CTE) are proposed in this paper. First, the principles of the coloration of PI films are briefly discussed, including the influence of the processing conditions on the film coloration, as well as the chemical and physical factors dominating the low CTE characteristics of the resultant PI films to clarify the challenges in simultaneously achieving excellent optical transparency, a very high Tg, a very low CTE, and excellent film toughness. A possible approach of achieving these target properties is to use semi-cycloaliphatic PI systems consisting of linear chain structures. However, semi-cycloaliphatic PIs obtained using cycloaliphatic diamines suffer various problems during precursor polymerization, cyclodehydration (imidization), and film preparation. In particular, when using trans-1,4-cyclohexanediamine (t-CHDA) as the cycloaliphatic diamine, a serious problem emerges: salt formation in the initial stages of the precursor polymerization, which terminates the polymerization in some cases or significantly extends the reaction period. The system derived from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) and t-CHDA can be polymerized by a controlled heating method and leads to a PI film with relatively good properties, i.e., excellent light transmittance at 400 nm (T400 = ~80%), a high Tg (>300 °C), and a very low CTE (10 ppm·K−1). However, this PI film is somewhat brittle (the maximum elongation at break, εb max is about 10%). On the other hand, the combination of cycloaliphatic tetracarboxylic dianhydrides and aromatic diamines does not result in salt formation. The steric structures of cycloaliphatic tetracarboxylic dianhydrides significantly influence the polymerizability with aromatic diamines and the CTE values of the resultant PI films. For three isomers of hydrogenated pyromellitic dianhydride, the steric structure effect on the polymerizability and the properties of the PI films is discussed. 1,2,3,4-Cyclobutanetetracarboxylic dianhydride (CBDA) is a very unusual cycloaliphatic tetracarboxylic dianhydride that is suitable for reducing the CTE. For example, the PI system derived from CBDA and 2,2′-bis(trifluoromethyl)benzidine (TFMB) yields a colorless PI film with a relatively low CTE (21 ppm·K−1). However, this PI is insoluble in common organic solvents, which means that it is neither solution-processable nor compatible with the chemical imidization process; furthermore, the film is somewhat brittle (εb < 10%). In addition, the effect of the film preparation route on the film properties is shown to be significant. Films prepared via chemical imidization always have higher optical transparency and lower CTE values than those prepared via the conventional two-step process (i.e., precursor casting and successive thermal imidization). These results suggest that compatibility with the chemical imidization process is the key for achieving our goal. To dramatically improve the solubility in the CBDA-based PI systems, a novel amide-containing aromatic diamine (AB-TFMB), which possesses the structural features of TFMB and 4,4′-diaminobenzanilide (DABA), is proposed. The CBDA(70);6FDA(30)/AB-TFMB copolymer has an ultra-low CTE (7.3 ppm·K−1), excellent optical transparency (T400 = 80.6%, yellowness index (YI) = 2.5, and haze = 1.5%), a very high Tg (329 °C), sufficient ductility (εb max > 30%), and good solution-processability. Therefore, this copolymer is a promising candidate for use as a novel coating-type plastic substrate material. This paper also discusses how the target properties can be achieved without the help of cycloaliphatic monomers. Thus, elaborate molecular design allows the preparation of highly transparent and low-CTE aromatic poly(amide imide) and poly(ester imide) systems.

Uniform alignment of rigid-rod liquid crystal (LC) molecules under applied voltage is critical for achievement of high-quality display for thin-film transistor-driven liquid crystal display devices (TFT-LCDs). The polymeric components that can induce the alignment of randomly aligned LC molecules are called alignment layers (ALs). In the current work, a series of organo-soluble polyimide (SPI) ALs were designed and prepared from an alicyclic dianhydride, hydrogenated 3,3′,4,4′-biphenyltetracarboxylic dianhydride (HBPDA), and various aromatic diamines, including 4,4′-methylenedianiline (MDA) for SPI-1, 4,4′-aminodianiline (NDA) for SPI-2, 3,3′,5,5′-tetramethyl-4,4′-diaminodiphenylmethane (TMMDA) for SPI-3, and 3,3′-diethyl-5,5′-dimethyl-4,4′-diaminodiphenylmethane (DMDEDA) for SPI-4. The derived SPI resins were all soluble in N-methyl-2-pyrrolidone (NMP). Four SPI alignment agents with the solid content of 6 wt.% were prepared by dissolving the SPI resins in the mixed solvent of NMP and butyl cellulose (BC) (NMP/BC = 80:20, weight ratio). Liquid crystal minicells were successfully fabricated using the developed SPI varnishes as the LC molecule alignment components. The SPI ALs showed good alignment ability for the LC molecules with the pretilt angles in the range of 1.58°–1.97°. The LC minicells exhibited good optoelectronic characteristics with voltage holding ratio (VHR) values higher than 96%. The good alignment ability of the SPI ALs is mainly attributed to the good comprehensive properties of the SPI layers, including high volume resistivity, high degree of imidization at the processing temperature (230 °C), good rubbing resistance, good thermal stability with glass transition temperatures (Tgs) higher than 260 °C, and excellent optical transparency with the transmittance higher than 97% at the wavelength of 550 nm.

Purpose Researchers are interested in examining the impact of visual display devices (VDDs) on the development of dry eye illness because their use is becoming more common among college students. The goal of this study was to see if there was a link between certain risk factors and the development of eye dryness in VDDs using young adults who wore contact lenses and those who did not. Methods The self-administrated survey was hosted in Google Forms, sent via e-mail to the participants. It consisted of two parts of assessing different risk factors (i.e., environmental conditions, angle of gaze, and years of VDD use) with contact lens use and Ocular Surface Disease Index (OSDI) questionnaire. The OSDI scores of the entire sample who suffer from dry eye and the subgroup using contact lenses were calculated. The relationship between different risk factors with the OSDI scores was also assessed. Results A total of 274 young adults from college students and academic staff (216 female, 58 male) were suffering from eye dryness. Eighty-eight of the 274 participants wore contact lenses. The mean OSDI scores of the 274 young adults were 32.92. Mean OSDI scores in contact lens wearers and non-wearers were 34.36 and 32.24, respectively ( p  < 0.01). There was a statistically significant relationship between OSDI score and indoor environmental conditions in computer using VDD group. Using a computer in a dark environment and above the line of sight resulted in a higher OSDI scores. Females who wore contact lenses while using a computer for more than three years had significantly higher OSDI scores than non-wearer females. Tablet type VDD use increased the mean ODSI scores of the contact lens wearers significantly. Conclusions Dry eye symptoms were shown to be increased in the contact lens wearer group with the increased duration of computer VDD use, decreased indoor environmental brightness conditions, and above the line of sight.

Addressing the urgent need for low-temperature processes in the manufacturing of flexible vehicle-mounted touch display devices, this study investigates the process–structure–performance relationships of indium tin oxide (ITO) thin films prepared by DC magnetron sputtering on transparent polyimide (CPI) substrates. A synergistic strategy of “low-temperature deposition (110 °C)–230 °C atmospheric annealing” was employed. The optimal sample exhibited excellent comprehensive performance: a resistivity as low as 203 μΩ·cm, an average visible light transmittance of 89.2%, a surface roughness of 0.76 nm, and the ability to endure 100,000 bending cycles at a radius of R = 5 mm with a sheet resistance change rate of less than 10%. Microstructural and chemical state analyses revealed that this process facilitates the complete oxidation of Sn2+ to Sn4+ (Sn4+/Sn2+ ratio of 8.2:1) and the controlled formation of oxygen vacancies (O_L/O_V ratio of 6.5:1), leading to a synergistic improvement in carrier concentration (8.7 × 1020 cm−3) and mobility (35.2 cm2/V·s). This work elucidates the crystallization kinetics and doping mechanisms under low-temperature conditions, providing a viable low-temperature technical pathway for the fabrication of high-performance transparent electrodes in flexible electronics.

The KDP-Potassium Dihydrogen Phosphate crystal is properly grown is confirmed by the single crystal XRD, which is further conceded for Co-60 irradiation with 100 Gy and converted to micro level by the process of milling. The KDP belongs to tetragonal crystalline system as per macro-scale reference and for micro-scale, the pure/bulk is milled for twenty hours for converting into micro-level and it is identified by the morphological pattern. The hardness profile of the KDP pure, micro (KDP-μ), 100 Gy macro (GKDP) are analyzed for the Vicker’s micro-hardness studies and identified the RISE impact as reverse indentation size effect. The micro-KDP morphology of 10 µm represents some proper isolated islands with void space. NLO-SHG of KDP micro and KDP 100 Gy are analyzed and found that pure KDP is 70 mV as the output for KDP as reference, KDP-micro is 71 mV and KDP-100 Gy is 73 mV; employed for phase matching proviso. The electronic filtering of KDP pure, micro, 100 Gy are pronounced in micron as variant influx for opto-electronic portrayal. The frequency doubling of the KDP pure, KDP micro, KDP 100 Gy is twice for normal case, 2.01, 2.07, and 2.15 for all the KDP. The powder diffraction pattern of the KDP confirms the grown KDP crystal samples; the display nature of the devices by KDP is identified for (111) profile. The electronic transition is by UV–visible spectrum for pure, micro and 100 Gy categories and identified the band gap as 6.1386 eV, 6.1084 eV and 6.0784 eV for the KDP-pure, KDP micro and 100 Gy and cut-off is pronounced as 202 nm, 203 nm and 204 nm, correspondingly. All the three samples are of highly transparent; the fluorescence effect of all samples are in the green color. The dielectric behavior of GKDP sample is analyzed and all the polarizations are referred through properly; the higher order value of super cell impacting of 3 × 3 × 3 case of KDP and the nano-tubular of 25 nm are well portrayed.

Displays are basic building blocks of modern electronics 1 , 2 . Integrating displays into textiles offers exciting opportunities for smart electronic textiles—the ultimate goal of wearable technology, poised to change the way in which we interact with electronic devices 3 – 6 . Display textiles serve to bridge human–machine interactions 7 – 9 , offering, for instance, a real-time communication tool for individuals with voice or speech difficulties. Electronic textiles capable of communicating 10 , sensing 11 , 12 and supplying electricity 13 , 14 have been reported previously. However, textiles with functional, large-area displays have not yet been achieved, because it is challenging to obtain small illuminating units that are both durable and easy to assemble over a wide area. Here we report a 6-metre-long, 25-centimetre-wide display textile containing 5 × 10 5 electroluminescent units spaced approximately 800 micrometres apart. Weaving conductive weft and luminescent warp fibres forms micrometre-scale electroluminescent units at the weft–warp contact points. The brightness between electroluminescent units deviates by less than 8 per cent and remains stable even when the textile is bent, stretched or pressed. Our display textile is flexible and breathable and withstands repeated machine-washing, making it suitable for practical applications. We show that an integrated textile system consisting of display, keyboard and power supply can serve as a communication tool, demonstrating the system’s potential within the ‘internet of things’ in various areas, including healthcare. Our approach unifies the fabrication and function of electronic devices with textiles, and we expect that woven-fibre materials will shape the next generation of electronics. A large electronic display textile that is flexible, breathable and withstands repeated machine-washing is integrated with a keyboard and power supply to create a wearable, durable communication tool.

Surgical training simulators with virtual reality have been developed to enable surgeons to efficiently acquire and improve their surgical skills. In hard tissue surgery, the surgeon uses a chisel and mallet to cut a bone or tooth with large and instantaneous forces. In the previous study by present authors, to represent the force sensation of the cutting operation in the virtual training simulator, we constructed the force display device using the ball-screw mechanism to obtain high stiffness and display the large force. Additionally, we applied the two-degrees-of-freedom (2DOF) admittance control to react instantaneously to the impact force by pounding with the mallet. The feedback controller of the 2DOF admittance control is required to increase the high-frequency gain for improving the responsiveness of the force display device. However, the vibrational mode of the force display device can be excited by increasing the controller gain. Therefore, this study develops the design approach of the feedback controller using the H ∞ control in the 2DOF admittance control system, which can be systematically constructed to reduce the vibrational mode and react instantaneously in the force display device. The efficacy of the proposed force display control system is verified through the virtual experience of the free movement and the hard contact operations.

A pixel in an electrowetting display (EWD) can be viewed as a confined water/oil two-phase microfluidic system that can be manipulated by applying an electric field. The phenomenon of charge trapping in the protective dielectric and conductivity of the oil phase reduce the effective electric field that is required to keep the three-phase contact line (TCL) in place. This probably leads to an oil-backflow effect which deteriorates the electro-optical performance of EWD devices. In order to investigate charge trapping and conduction effects on the device electro-optical response, an EWD device was studied, which was fabricated with a black oil, aiming for a high-contrast ratio and color-filter display. For comparison, we also prepared a device containing a purple oil, which had a lower electrical conductivity. As anticipated, the black-oil device showed faster backflow than the purple-oil device. A simple model was proposed to explain the role of oil conductivity in the backflow effect. In addition, the rebound and reopening effects were also observed after the voltage was switched to zero. The above observations were strongly dependent on polarity. By combining observations of the polarity dependence of the oil conductivity and assuming that negative charges trap more strongly in the dielectric than positive charges, our experimental results on rebound and reopening can be explained. In the AC optical response, the pixel closing speed decreased in time for intermediate frequencies. This is likely related to the phenomenon of charge trapping. It was also found that the periodic driving method could not suppress the backflow effect when the driving frequency was above ~10 kHz. Our findings confirm the significance of the above charge-related effects of EWD devices, which need to be investigated further for better understanding in order to properly design/use materials and driving schemes to suppress them.

ABSTRACT Phage display technology, which is based on the presentation of peptide sequences on the surface of bacteriophage virions, was developed over 30 years ago. Improvements in phage display systems have allowed us to employ this method in numerous fields of biotechnology, as diverse as immunological and biomedical applications, the formation of novel materials and many others. The importance of phage display platforms was recognized by awarding the Nobel Prize in 2018 ‘for the phage display of peptides and antibodies’. In contrast to many review articles concerning specific applications of phage display systems published in recent years, we present an overview of this technology, including a comparison of various display systems, their advantages and disadvantages, and examples of applications in various fields of science, medicine and the broad sense of biotechnology. Other peptide display technologies, which employ bacterial, yeast and mammalian cells, as well as eukaryotic viruses and cell-free systems, are also discussed. These powerful methods are still being developed and improved; thus, novel sophisticated tools based on phage display and other peptide display systems are constantly emerging, and new opportunities to solve various scientific, medical and technological problems can be expected to become available in the near future.

Face recognition is a widely used biometric technology because it is both user friendly and more convenient to use than other biometric approaches. However, naïve face recognition systems that do not support any type of liveness detection can be easily spoofed using just a photograph of a valid user. Face liveness detection is a key issue in the field of security systems that use a camera. Unfortunately, it is not easy to detect face liveness using existing methods, assuming that there are print failures and overall image blur. With the development of display devices and image capturing technology, it is possible to reproduce face images similar to real faces. Therefore, the number of attacks using a photograph or video displayed on a screen rather than paper will increase. In this study, we compare test results using live faces and high-definition face videos from light-emitting diode (LED) display devices and analyze the changes in face recognition performance according to the lighting direction. Experimental results show that there is no significant difference between live faces and not live faces under good lighting conditions. We suggest the use of gamma to reduce the performance gap between the two faces under poor lighting conditions. From these results, we can provide key solutions to resolve the issues associated with texture-based approaches.