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Excessive smartphone use has been related to numerous negative outcomes including anxiety, depression, sleep deficits, and lower life satisfaction. Though empirical works have made these associations, prior works have not addressed how to make phones less appealing and reduce screen time. One hundred sixty-one undergraduate students participated in a longitudinal study of smartphone use. Seventy-three had their phones changed to grayscale for eight to 10 days to evaluate if the absence of bright and saturated colors reduces screen time and negative affectivity. Participants who had their phones in grayscale spent significantly less time on social media and internet browsing compared to Time 1, though it appears grayscale did not influence video screen time. In addition, total screen time was significantly less for these individuals by an average of 37.90 min each day. The influence of grayscale did not account for improvement in anxiety or depression symptomology as both control and experimental groups improved compared to Time 1. It appears changing to grayscale makes smartphones less gratifying and can assist individuals in controlling their smartphone use. Suggestions and implications for future research are outlined. [ABSTRACT FROM AUTHOR]

Metasurfaces composed of regularly arranged and deliberately oriented metallic nanoparticles can be employed to manipulate the amplitude, phase and polarization of an incident electromagnetic wave. The metasurfaces operating in the visible to near infrared spectral range rely on the modern fabrication technologies which offer a spatial resolution beyond the optical diffraction limit. Although direct laser writing is an alternative to the fabrication of nanostructures, the achievement of regular nanostructures with deep-subwavelength periods by using this method remains a big challenge. Here, we proposed and demonstrated a novel strategy for regulating disordered plasmonic nanoparticles into nanogratings with deep-subwavelength periods and reshaped nanoparticles by using femtosecond laser pulses. The orientations of the nanogratings depend strongly on the polarization of the femtosecond laser light. Such nanogratings exhibit reflection and polarization control over the reflected light, enabling the realization of polarization sensitive optical memory and color display with high spatial resolution and good chromacity.

Non-volatile storage memory is widely considered to be one of the most promising candidates to replace dynamic random access memory and even static random access memory. It has recently received particular attention because of its great potential for brain-like neuromorphic applications. Phase-change materials, also known as Chalcogenide alloys, exhibit several especially advantageous traits for non-volatile applications. These include scalability, fast switching speeds, low switching energy and outstanding thermal stability. As a result, most research to date has sought to identify electrical applications for phase-change materials in relation to phase-change random access memory, phase-change memristors and phase-change neuro networks, while overlooking their potential for non-volatile photonic applications. To address this issue, we provide a comprehensive review that examines the remarkable physical properties of phase-change materials for photonic applications, together with emerging phase-change photonic devices. The review begins by presenting the atomic structure and physical properties of phase-change materials, followed by an elaboration of the issues that phase-change materials are currently facing and the strategies being developed to overcome them. The current state-of-the-art and technical challenges confronting phase-change materials in relation to non-volatile photonic applications, such as phase-change photonic memory, phase-change photonic neuro-networks, phase-change metasurfaces and phase-change color displays are then considered. The review concludes by discussing the outlook for successfully implementing phase-change materials in emerging photonic domains.

Next‐generation color display entails miniaturization, reconfigurablity, flexibility, integration, and excellent workability. Recently, emerging 2D van der Waals materials offer a new opportunity to satisfy these requirements and attract intense attention, owing to their intrinsic in‐plane anisotropy for polarization dependent photosensitivity, straightforward integration with complicated nanostructures, and efficient quantum confinement for good photodetecting performances. Nevertheless, reconfigurable color display in the visible region based on the 2D material stays elusive. Black phosphorus (BP) is a newly rising member of 2D family with intense optical anisotropy. Herein, the anisotropic BP crystals are explored as an optical dielectric for the visible spectrum, which possesses a polarization‐dependent complex refractive index. A considerably large anisotropic ratio of BP enables polarized color displaying. It is experimentally and theoretically observed that the color from an air/BP/SiO2 multi‐layered Fabry–Pérot cavity reversibly changes with the polarization angle, taking advantage of polarization‐dependent complex refractive index of BP. The strategy offers a new prospect for developing next‐generation polarization‐dependent devices in data storage, anti‐counterfeiting technologies, and color display. [ABSTRACT FROM AUTHOR]

Radiative cooling technology radiates heat into cold space through the atmospheric window without external energy. Integrating color display and radiative cooling is necessary to meet both aesthetic and practical requirements in real-life applications. In this study, we developed an efficient colored radiative cooler by depositing a cone emitter on an elliptical metal-insulator-metal (MIM) reflector. The upper emitter has an average emissivity of 96.62 % in the atmospheric window, while the lower part is tuned to achieve specific colors. Besides the tunability of geometry parameters, it is possible to produce diverse color display without re-modification of the structure by varying the polarization angle. Meanwhile, high emissivity can be achieved at different incident angles. Finally, the colored logo of Zhengzhou University (ZZU) is realized in our design with the polarization angles of 0° and 45° for comparison. Unlike conventional radiative coolers, our proposed cooler not only adjusts color display through geometry parameters or polarization angle, but also possesses a highly efficient cooling power. These advantages open up new avenues for energy saving, cooling, and color display. • A cone emitter on an elliptical MIM reflector has been designed to achieve radiative cooling and aesthetic performance. • A high emissivity of 96.62 % has been achieved in the first transparency window with the top SiO 2 cone. • A specific color can be flexibly tuned with the structural parameters and polarization angle. • Controllable emissivity and radiative cooling power are further realized with different incident angles. [ABSTRACT FROM AUTHOR]

Our research group has been developing an aero signage display. The word 'aero' means that its image is floating in the air. The authors have noticed that the important technology in aero signage is 'transparent.' Suppose you find out window decals which are put on the glass window of shops. You end up watching the mirrored images if you watch the decals on transparent glass window from inside of the shop. In aero signage, the technique which enables to display unidirectional (or one‐way) observable image(viewing angle control) is very important. Our proposed self‐assembly joint mechanism is one of the essential technology for aero signage which enables to make transparent view from back side. [ABSTRACT FROM AUTHOR]

Structural colors emerge when a particular wavelength range is filtered out from a broadband light source. It is regarded as a valuable platform for color display and digital imaging due to the benefits of environmental friendliness, higher visibility, and durability. However, current devices capable of generating colors are all based on direct transmission or reflection. Material loss, thick configuration, and the lack of tunability hinder their transition to practical applications. In this paper, a novel mechanism that generates high-purity colors by photon spin restoration on ultrashallow plasmonic grating is proposed. We fabricated the sample by interference lithography and experimentally observed full color display, tunable color logo imaging, and chromatic sensing. The unique combination of high efficiency, high-purity colors, tunable chromatic display, ultrathin structure, and friendliness for fabrication makes this design an easy way to bridge the gap between theoretical investigations and daily-life applications.

Holographic color display is realized with white light as illumination by controlling the spectral components in frequency domain. Spectral components control method using the parameters of existing high resolution spatial light modulator (SLM) is demonstrated. An optical system including a white light source, an achromatic collimating lens, a high resolution spatial light modulator, a 4f optical filtering system and an achromatic lens as eyepiece is designed and developed for holographic color display. The effectiveness of the proposed technique is proved by experiments. [ABSTRACT FROM AUTHOR]

Holographic color display is realized with white light as illumination by controlling the spectral components in frequency domain. Spectral components control method using the parameters of existing high resolution spatial light modulator (SLM) is demonstrated. An optical system including a white light source, an achromatic collimating lens, a high resolution spatial light modulator, a 4f optical filtering system and an achromatic lens as eyepiece is designed and developed for holographic color display. The effectiveness of the proposed technique is proved by experiments. [ABSTRACT FROM AUTHOR]

The effect of observer metamerism induced by electronic displays depends to a large extent on their primary spectra (red, green, and blue in the most common case). In particular, for narrow-band primary spectra whose peak wavelength lies in the range of high variability of the observer's color-matching function, some observers can experience very large differences between actual surface colors (e.g. in a light booth) and displayed colors if the monitor is optimized for the International Commission on Illumination (CIE) 1931 standard observer. However, because narrow-band light-emitting diodes lead to larger color gamuts, more and more monitors with very narrow band primaries are coming onto the market without manufacturers taking into account the associated problem of observer variations. Being able to measure these variations accurately and efficiently is therefore an important objective. In this paper, we propose a new approach to predict the extent of observer metamerism for a particular multiprimary display. Unlike existing dedicated models, ours does not depend on a reference illuminant and a set of reflectance spectra and is computationally more efficient. [ABSTRACT FROM AUTHOR]

We describe a computer simulation technique for generating the monochromatic light diffraction from arbitrary apertures. For the Fresnel diffraction of rectangular and circular apertures, a simple form of equation for the light intensity distribution is derived. A method for displaying the color of monochromatic light on the monitor is presented. On this basis, we implement the diffraction simulation of white light formed via mixing three monochromatic lights of λ = 700; 546.1; 435.8 nm with the same ratio in the RGB color space of CIE1931 system. [ABSTRACT FROM AUTHOR]

Purpose: The authors discuss measurement methods and instrumentation useful for the characterization of the gray tracking performance of medical color monitors for diagnostic applications. The authors define gray tracking as the variability in the chromaticity of the gray levels in a color monitor. Methods: The authors present data regarding the capability of color measurement instruments with respect to their abilities to measure a target white point corresponding to the CIE Standard Illuminant D65 at different luminance values within the grayscale palette of a medical display. The authors then discuss evidence of significant differences in performance among color measurement instruments currently available for medical physicists to perform calibrations and image quality checks for the consistent representation of color in medical displays. In addition, the authors introduce two metrics for quantifying grayscale chromaticity consistency of gray tracking. Results: The authors' findings show that there is an order of magnitude difference in the accuracy of field and reference instruments. The gray tracking metrics quantify how close the grayscale chromaticity is to the chromaticity of the full white point (equal amounts of red, green, and blue at maximum level) or to consecutive levels (equal values for red, green, and blue), with a lower value representing an improved grayscale tracking performance. An illustrative example of how to calculate and report the gray tracking performance according to the Task Group definitions is provided. Conclusions: The authors' proposed methodology for characterizing the grayscale degradation in chromaticity for color monitors that can be used to establish standards and procedures aiding in the quality control testing of color displays and color measurement instrumentation. [ABSTRACT FROM AUTHOR]

The aim of the present study was to analyze the display of colors in digital projection. For this purpose the digital projector NEC NP210 was used. The measurements were performed in accordance with the instructions and recommendations of ISO standards. Our goal was to research the creation of color profile of the projector using a EyeOne Pro spectrophotometer and to establish whether the size of color gamut of standardized sRGB color space can be reached by characterization of the digital projector modules. By using the color chart Color Checker Classic, the photometric and colorimetric accuracy of the characterized and uncharacterized projection were evaluated. In the final part of the research, comparison between the colorimetric accuracy of the computer screen and the digital projector was performed. The results showed that by module characterization of the NEC NP210 Movie projector in studio conditions, the same size of the color space could not be achieved as by using the default sRGB module. Evaluation of colorimetric accuracy by using the digitalized color chart Color Checker Classic provides usable results, especially when the display of chromatic colors with emphasis on skin tones, and achromatic colors with emphasis on grey balance or chromaticity respectively, were examined. Based on the obtained results of the computer screen and digital projector comparison, it could be concluded that both compared computer screens match the standards. Overall, the NEC NP210 projector with the sRGB default module without profile could be also used if necessary. Thus, we can sum up that digital projection displaying standardized sRGB color space could not be comparable to a high quality CRT or LCD computer screen. [ABSTRACT FROM AUTHOR]

Background The use of colors in visual displays can facilitate visual search and perception, but their use may not be effective without consideration of differences in the interpretation of their connoted meanings between individuals of different occupational backgrounds. Objective This study examined color-concept associations for Hong Kong Chinese students and white-collar workers, and then compared their associations with those of two other occupational groups to assess whether occupational background is related to color-concept associations. Method A questionnaire survey was used to examine color-concept associations among 100 university students and 100 white-collar workers in Hong Kong. The participants were presented with 16 safety-related concepts and were asked to choose one of 10 colors that best represented each concept. The associations reported by four groups with different occupations (the two groups in this study and the groups of managerial staff and steel workers examined in our previous study) were compared. A chi-square test was applied to determine whether significant color association(s) existed for each concept. Results Our results revealed that each concept was significantly associated with at least one color ( p < 0.01). The Hong Kong white-collar workers and managerial staff in mainland China both expressed the same color associations for 14 of the tested concepts, and differed only over which colors were associated with “strong,” and “radiation hazard.” These findings generally suggest that populations with similar occupations can have similar color perceptions. However, the students and the other three employee groups reported different color associations with the concepts “normal,” “off” and “potential hazard.” Conclusions Occupational background is associated with how color is interpreted for its connoted meaning. One should consider occupational background carefully when choosing colors in product designs, especially for safety. [ABSTRACT FROM AUTHOR]

Purpose: Even though the use of color in the interpretation of medical images has increased significantly in recent years, the ad hoc manner in which color is handled and the lack of standard approaches have been associated with suboptimal and inconsistent diagnostic decisions with a negative impact on patient treatment and prognosis. The purpose of this study is to determine if the choice of color scale and display device hardware affects the visual assessment of patterns that have the characteristics of functional medical images. Methods: Perfusion magnetic resonance imaging (MRI) was the basis for designing and performing experiments. Synthetic images resembling brain dynamic-contrast enhanced MRI consisting of scaled mixtures of white, lumpy, and clustered backgrounds were used to assess the performance of a rainbow ("jet"), a heated black-body ("hot"), and a gray ("gray") color scale with display devices of different quality on the detection of small changes in color intensity. The authors used a two-alternative, forced-choice design where readers were presented with 600 pairs of images. Each pair consisted of two images of the same pattern flipped along the vertical axis with a small difference in intensity. Readers were asked to select the image with the highest intensity. Three differences in intensity were tested on four display devices: a medical-grade three-million-pixel display, a consumer-grade monitor, a tablet device, and a phone. Results: The estimates of percent correct show that jet outperformed hot and gray in the high and low range of the color scales for all devices with a maximum difference in performance of 18% (confidence intervals: 6%, 30%). Performance with hot was different for high and low intensity, comparable to jet for the high range, and worse than gray for lower intensity values. Similar performance was seen between devices using jet and hot, while gray performance was better for handheld devices. Time of performance was shorter with jet. Conclusions: Our findings demonstrate that the choice of color scale and display hardware affects the visual comparative analysis of pseudocolor images. Follow-up studies in clinical settings are being considered to confirm the results with patient images. [ABSTRACT FROM AUTHOR]

Two types of dielectrophoretic liquid displays with patterned quantum dots (QDs) array for enhancing the color performance are demonstrated. QDs not only provide vivid color (~136% AdobeRGB in CIE1976 color space) but also greatly improve light efficiency by reducing the optical loss from color filters. These polarizer-free liquid displays offer vivid colors, high transmittance, wide viewing angle, and modest response time and contrast ratio. They are promising candidates for E-book and mobile display applications. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the optical properties of stacked right- and left-hand chiral photonic crystal layers. The reflection spectra peculiarities of this system were investigated showing that, in contrast to a single CLC layer, there are multiple PBGs. The Eigen polarizations (EP) of the system are degenerated and the polarization plane rotation decreases if the system thickness is increased; the rotation sign depends on the first sublayer chirality sign. We also investigated the influence of sublayer thicknesses, sublayer local dielectric anisotropies, and sublayer helix pitches on the reflection peculiarities of the system. [ABSTRACT FROM AUTHOR]

In this paper, we present a nonstationary Markov random field (MRF) fusion model for the color display of hyperspectral images. The proposed fusion or dimensionality reduction model is derived from the preservation of spectral distance criterion. This quantitative metric of good dimensionality reduction and meaningful visualization allows us to derive an appealing fusion model of high-dimensional spectral data, expressed as a Gibbs distribution or a nonstationary MRF model defined on a complete graph. In this framework, we propose a computationally efficient coarse-to-fine conjugate-gradient optimization method to minimize the cost function related to this energy-based fusion model. The experiments reported in this paper demonstrate that the proposed visualization method is efficient (in terms of preservation of spectral distances and discriminality of pixels with different spectral signatures) and performs well compared to the best existing state-of-the-art multidimensional imagery color display methods recently proposed in the literature. [ABSTRACT FROM AUTHOR]

This paper investigates RGB color composition schemes for hyperspectral imagery display. A three-channel composite inevitably loses a significant amount of information contained in the original high-dimensional data. The objective here is to display the useful information as distinctively as possible for high-class separability. To achieve this objective, it is important to find an effective data processing step prior to color display. A series of supervised and unsupervised data transformation and classification algorithms are reviewed, implemented, and compared for this purpose. The resulting color displays are evaluated in terms of class separability using a statistical detector and perceptual color distance. We demonstrate that the use of the data processing step can significantly improve the quality of color display, whereas data classification generally outperforms data transformation, although the implementation is more complicated. Several instructive suggestions for practitioners are provided. [ABSTRACT FROM AUTHOR]

Color displays, such as the ones we find in computers, telephones and PDAs, can cause accessibility problems for colorblind people. The solution can be found in a careful combination of color signals with additional visual cues, and in an optimal color selection. Web designers can use a number of web sites where they can test their design, simulating it as colorblind people would perceive it. [ABSTRACT FROM AUTHOR]

A three-channel integrated wideband video IC with the possibility of application in high resolution display of lM pixel was developed. This paper reports first the construction of a wideband voltage amplifier circuit in which a wide output signal dynamic range is obtained. With respect to the construction of this circuit, by compensating for the nonlinearity of the bipolar transistor and the logarithmic compression of the signal voltage, an attempt is made to expand the dynamic range. Moreover, by using an opposite- phase current to cancel the negative resistance component appearing in the input impedance when compensating for the nonlinearity, it was attempted to flatten the frequency characteristic. With the present circuit construction, by overcoming the process limitation of low-voltage tolerance, it was possible to ensure wideband characteristics in excess of 140 MHz. In addition, the wideband suppression method of signal crosstalk appearing between channels as side effects of tracking characteristic improvement due to three-channel integration is reported. By suppressing the influence of common impedance and the differential transmission of each signal, it was possible to suppress lower than -43.6 dB the crosstalk between channels below 100 MHz. By the development of this IC, the miniaturization and lowering of cost of high-resolution display and the improvement of adjustment accuracy and stability characteristics could be achieved. [ABSTRACT FROM AUTHOR]

Liquid crystal microdroplets trapped into silica gel-glasses by sol-gel processes may be used for display applications. Gel-glass dispersed liquid crystals (GDLC) are switched between opaque and transparent states by applying external AC-voltage signals; no polarizers are required. The feasibility of applying these materials to colored displays has been explored. A comparative study of different dyes for GDLC color displays, which were either embedded in the sol-gel matrix or dissolved in the liquid crystal microdroplets is presented. [ABSTRACT FROM AUTHOR]

The field confinement of plasmonic systems enables spectral tunability under structural variations or environmental perturbations, which is the principle for various applications including nanorulers, sensors, and color displays. Here, we propose and demonstrate that materials with anomalous dispersion, such as Ge in the visible, improve spectral tunability. We introduce our proposal with a semianalytical guided mode picture. Using Ge-based film (Ag/Au)-coupled gap plasmon resonators, we implement two architectures and demonstrate the improved tunability with single-particle dark-field scattering, ensemble reflection, and color generation. We observe three-fold enhancement of tunability with Ge nanodisks compared with that of Si, a normal-dispersion material in the visible. The structural color generation of large array systems, made of inversely fabricated Ge-Ag resonators, exhibits a wide gamut. Our results introduce anomalous material dispersion as an extra degree of freedom to engineer the spectral tunability of plasmonic systems, especially relevant for actively tunable plasmonics and metasurfaces.

Metasurface-based color display and holography have greatly advanced the state of the art display technologies. To further enrich the metasurface functionalities, recently a lot of research endeavors have been made to combine these two display functions within a single device. However, so far such metasurfaces have remained static and lack tunability once the devices are fabricated. In this work, we demonstrate a dynamic dual-function metasurface device at visible frequencies. It allows for switching between dynamic holography and dynamic color display, taking advantage of the reversible phase transition of magnesium through hydrogenation and dehydrogenation. Spatially arranged stepwise nanocavity pixels are employed to accurately control the amplitude and phase of light, enabling the generation of high-quality color prints and holograms. Our work represents a paradigm toward compact and multifunctional optical elements for future display technologies.

Objective: To assess the effect of the colorized display of digital mammograms on observer detection of subtle breast lesions., Methods: Three separate observer studies compared detection performance using grayscale versus color display of 1) low-contrast mass-like objects in a standardized mammography phantom; 2) simulated microcalcifications in a background of normal breast parenchyma; and 3) standard-of-care clinical digital mammograms with subtle calcifications and masses. Colorization of the images was done by displaying each image pixel in blue, green, and red hues, or gray, maintaining DICOM-calibrated luminance scale and consistent luminance range. For the simulated calcifications and clinical mammogram studies, comparison of detection rates was computed using McNemar's test for paired differences., Results: For the phantom study, mass-like object detection was significantly better using a green colormap than grayscale (73.3% vs 70.8%, P = .009), with no significant improvement using blue or red colormaps (72.6% and 72.5%, respectively). For simulated microcalcifications, no significant difference was noted in detection using the green colormap, as compared with grayscale. For clinical digital screening mammograms, no significant difference was noted between gray and green colormaps for detection of microcalcifications. Green color display, however, resulted in decreased sensitivity for detection of subtle masses (63% vs 69%, P = .03)., Conclusion: Although modest improvement was demonstrated for a detection task using colorized display of a standard mammography phantom, no significant improvement was demonstrated using a color display for a simulated clinical detection task, and actual clinical performance was worse for colorized display of mammograms in comparison to standard grayscale display., (© Society of Breast Imaging 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)