Display Pixel Research Articles

Fabrication of Vertically Aligned InGaN/GaN Nanorod Light Emitting Diode Arrays Using Dielectrophoresis.

We report a novel strategy for vertical alignment of nanorod light emitting diodes (NRLs) by introducing dielectrophoresis (DEP) coupled with a nanohole electrode (NHE). The NHE consists of two electrodes placed at the top and the bottom separated by an insulating layer. This electrode structure allows NRLs to align within the nanoholes due to the nonuniform electric field generated across the entire region of the nanohole when a DEP voltage is applied. Our strategy involves optimizing the nanohole dimensions (diameter and height) to ensure the vertical positioning and alignment of NRLs within the nanohole, rather than laying them down horizontally. The NHE arrays with relatively large dimensions of 30 × 30 and 50 × 50 μm2 exhibit alignment yields of 76% and 58%, respectively. Additionally, the smaller NHE dimension of 10 × 10 μm2 achieves a 100% alignment yield, thereby enabling the fabrication of ultrasmall pixels. This approach represents a highly feasible direction for the precise placement of individual NRLs at a specific location, leading to the development of ultrasmall, high-resolution display pixels.

Nonsymmetrical thermal conductivity along the director field in ferroelectric nematic liquid crystals.

The synthesis of ferroelectric nematic liquid crystals (FNLCs) concludes the long wait for their existence and potential usage in multiple liquid crystal based applications. In FNLCs, electric polarization in the nematic phase significantly decreases the switching time of in-on display pixels. In this article, we report the occurrence of translation symmetry breaking for heat propagation along the director field n[over ̂] in the ferroelectric nematic phase. Due to the C_{∞V} symmetry of such a phase and close similarity to the bent-core polar liquid crystal phase, a rank-3 tensor describes its scalar order parameter and algebraic deductions. The finite element simulations show the occurrence of the nonsymmetrical thermal conductivity along n[over ̂]. The preferential heat transport in FNLCs can allow them to work as an all-thermal monophase non-nanostructured single-material thermal rectifier. We expect that this study will contribute towards the FNLCs application as functional layers and inks.

Impact of Display Sub-Pixel Arrays on Perceived Gloss and Transparency.

In recent years, improvements in display image quality have made it easier to perceive rich object information, such as gloss and transparency, from images, known as shitsukan. Do the different display specifications in the world affect their appearance? Clarifying the effects of differences in pixel structure on shitsukan perception is necessary to realize shitsukan management for displays with different hardware structures, which has not been fully clarified before. In this study, we experimentally investigated the effects of display pixel arrays on the perception of glossiness and transparency. In a visual evaluation experiment, we investigated the effects of three types of sub-pixel arrays (RGB, RGBW, and PenTile) on the perception of glossiness and transparency using natural images. The results confirmed that sub-pixel arrays affect the appearance of glossiness and transparency. A general relationship of RGB > PenTile > RGBW for glossiness and RGB > RGBW > PenTile for transparency was found; however, detailed analysis, such as cluster analysis, confirmed that the relative superiority of these sub-pixel arrays may vary depending on the observer and image content.

P‐122: Dependence of Aerial image quality on Display parameters in aerial Display system

In this paper, we report the relationship between the imaging spatial resolution and display parameters of the AIRR (aerial imaging by retro‐reflection) system, which we constructed using displays of different brightness, luminance spatial distribution and pixel pitch, respectively, and a line‐pair MTF‐based measurement method is applied to the system. The MTF measurement results show that the spatial resolution depends on the display pixel period size, luminance intensity and luminance spatial distribution.

Wide field-of-view light-field head-mounted display for virtual reality applications

Light-field head-mounted displays (HMDs) can resolve vergence-accommodation conflicts but suffer from limited display pixels, causing a narrow field-of-view (FOV). This study proposes a wide-FOV light-field HMD with a 5.5-inch-diagonal 4 K display for virtual reality applications. By adjusting the pitch of elemental images to control the eye relief and creating a virtual intermediate image, horizontal and vertical FOVs of 68.8° and 43.1°, respectively, can be achieved using a monocular optical bench prototype.

Ultrafast Nanodrum-on-Chip Pixels.

Environmentally friendly, ultrafast display pixels of micrometer sizes are fabricated with nanometer-thick gold films and Si/SiO2 wafers. The color displayed is due to both the plasmon response of the gold film and the optical interference from the Fabry-Peerot cavity formed by the underlying silicon substrate, the semitransparent gold film and the air gap between them. When an electric potential is applied to the gold film, the electrostatic force induces an attraction between the gold film and the silicon wafer. Due to the flexibility of the film, the size of the air gap changes, resulting in a changing color. By applying different driving signals, we have achieved cyan, magenta, and yellow reflected colors. The maximum switching rate of the pixel is primarily determined by the thickness dependence of the metal drum and its Young's modulus and is typically in the MHz regime.

Wireless magnetoelectrically powered organic light-emitting diodes.

Compact wireless light sources are a fundamental building block for applications ranging from wireless displays to optical implants. However, their realization remains challenging because of constraints in miniaturization and the integration of power harvesting and light-emission technologies. Here, we introduce a strategy for a compact wirelessly powered light-source that consists of a magnetoelectric transducer serving as power source and substrate and an antiparallel pair of custom-designed organic light-emitting diodes. The devices operate at low-frequency ac magnetic fields (~100 kHz), which has the added benefit of allowing operation multiple centimeters deep inside watery environments. By tuning the device resonance frequency, it is possible to separately address multiple devices, e.g., to produce light of distinct colors, to address individual display pixels, or for clustered operation. By simultaneously offering small size, individual addressing, and compatibility with challenging environments, our devices pave the way for a multitude of applications in wireless displays, deep tissue treatment, sensing, and imaging.

Cd0.2Zn0.8O nanowire thin film transistor for low kickback high-speed AMLCD circuit applications

This paper reports the Cd0.2Zn0.8O channel cylindrical gate-all-around nanowire thin-film transistor (CY-GAA-NWTFT) for high-speed active-matrix liquid crystal display (AMLCD) pixel circuit with minimal kickback voltage. The AC/DC, analog, and energy efficiency of this device are investigated against the variation in lateral (channel length) as well as vertical dimension (oxide thickness) using technology computer aided design (TCAD) device simulation environment. Further, the behavior of CY-GAA-TFT is crosschecked by implementing it on resistive load digital inverter circuit followed by transient analysis to calculate delay of the inverter circuit. Moreover, static analysis has been also performed to evaluate its voltage transfer curve (VTC) to derive its noise margin and voltage gain. The execution of the proposed CY-GAA-NWT device on AMLCD pixel circuit indicates tremendous improvement in performance in terms of high-speed applications and low kickback voltage.

Multiresonant all-dielectric metasurfaces based on high-order multipole coupling in the visible.

In many cases, optical metasurfaces are studied in the single-resonant regime. However, a multiresonant behavior can enable multiband devices with reduced footprint, and is desired for applications such as display pixels, multispectral imaging and sensing. Multiresonances are typically achieved by engineering the array lattice (e.g., to obtain several surface lattice resonances), or by adopting a unit cell hosting one (or more than one) nanostructure with some optimized geometry to support multiple resonances. Here, we present a study on how to achieve multiresonant metasurfaces in the visible spectral range by exploiting high-order multipoles in dielectric (e.g., diamond or titanium dioxide) nanostructures. We show that in a simple metasurface (for a fixed particle and lattice geometry) one can achieve triple resonance occurring nearly at RGB (red, green, and blue) wavelengths. Based on analytical and numerical analysis, we demonstrate that the physical mechanism enabling the multiresonance behavior is the lattice induced coupling (energy exchange) between high-order Mie-type multipoles moments of the metasurface's particles. We discuss the influence on the resonances of the metasurface's finite size, surrounding material, polarization, and lattice shape, and suggest control strategies to enable the optical tunability of these resonances.

The Effect of Ad Image's Sentiment Scores and Mobile Device Attributes on Mobile Ad Response Behavior

Using a state-of-the-art image processing algorithm applied to mobile ad creative and a unique dataset on technology features for mobile platforms, we examine how visual sentiment of mobile ad images, mobile device attributes that aid visual communication, and their interactions influence consumers’ mobile ad responses. Our results show that an increase in mobile ads’ valence and arousal levels by one-unit enhances the instantaneous probability of consumers’ mobile ad response by 2.4% and 1.6%, respectively. An increase in mobile devices’ display size and pixel density by 1 in and 1%, respectively, decreases the probability of mobile ad response by 42.6% and 0.7%. Interestingly, display size positively moderates the effect of arousal, while pixel density positively moderates the effect of valence on consumers’ mobile ad responses. This study contributes to the IS and marketing literature by examining the role of ad images’ visual sentiment scores such as valence and arousal, device-specific attributes on mobile display, such as screen display size and pixel density, and their interaction effects on consumers’ mobile ad response behaviors. Importantly, the application of computationally efficient image sentiment processing sheds new light on the extant mobile advertising and marketing literature both from a methodological and findings perspective.

Near-Infrared Nanophosphors Based on CuInSe2 Quantum Dots with Near-Unity Photoluminescence Quantum Yield for Micro-LEDs Applications.

Highly efficient near-infrared (NIR) luminescent nanomaterials are urgently required for portable mini or micro phosphors-converted light-emitting diodes (pc-LEDs). However, most existing NIR-emitting phosphors are generally restricted by their low photoluminescence (PL) quantum yield (QY) or large particle size. Herein, a kind of highly efficient NIR nanophosphors is developed based on copper indium selenide quantum dots (CISe QDs). The PL peak of these QDs can be exquisitely manipulated from 750 to 1150nm by altering the stoichiometry of Cu/In and doping with Zn2+ . Their absolute PLQY can be significantly improved from 28.6% to 92.8% via coating a ZnSe shell. By combining the phosphors with a commercial blue chip, an NIR pc-LED is fabricated with remarkable photostability and a record-high radiant flux of 88.7 mW@350mA among the Pb/Cd-free QDs-based NIR pc-LEDs. Particularly, such QDs-based nanophosphors acted as excellent luminescence converter for NIR micro-LEDs with microarray diameters below 5µm, which significantly exceeds the resolutions of current commercial inkjet display pixels. The findings may open new avenues for the exploration of highly efficient NIR micro-LEDs in a variety of applications.

A reflective display based on the electro-microfluidic assembly of particles within suppressed water-in-oil droplet array

Reflective displays have stimulated considerable interest because of their friendly readability and low energy consumption. Herein, we develop a reflective display technique via an electro-microfluidic assembly of particles (eMAP) strategy whereby colored particles assemble into annular and planar structures inside a dyed water droplet to create “open” and “closed” states of a display pixel. Water-in-oil droplets are compressed within microwells to form a pixel array. The particles dispersed in droplets are driven by deformation-strengthened dielectrophoretic force to achieve fast and reversible motion and assemble into multiple structures. This eMAP based device can display designed information in three primary colors with ≥170° viewing angle, ~0.14 s switching time, and bistability with an optimized material system. This proposed technique demonstrates the basis of a high-performance and energy-saving reflective display, and the display speed and color quality could be further improved by structure and material optimization; exhibiting a potential reflective display technology.

Three-Dimensionally Printed, Vertical Full-Color Display Pixels for Multiplexed Anticounterfeiting.

Information encryption strategies have become increasingly essential. Most of the fluorescent security patterns have been made with a lateral configuration of red, green, and blue subpixels, limiting the pixel density and security level. Here we report vertically stacked, luminescent heterojunction micropixels that construct high-resolution, multiplexed anticounterfeiting labels. This is enabled by meniscus-guided three-dimensional (3D) microprinting of red, green, and blue (RGB) dye-doped materials. High-precision vertical stacking of subpixel segments achieves full-color pixels without sacrificing lateral resolution, achieving a small pixel size of ∼μm and a high density of over 13,000 pixels per inch. Furthermore, a full-scale color synthesis for individual pixels is developed by modulating the lengths of the RGB subpixels. Taking advantage of these unique 3D structural designs, trichannel multiplexed anticounterfeiting Quick Response codes are successfully demonstrated. We expect that this work will advance data encryption technology while also providing a versatile manufacturing platform for diverse 3D display devices.

Biaxially Stretchable Active‐Matrix Micro‐LED Display with Liquid Metal Interconnects

AbstractA stretchable active‐matrix (AM) display is a next‐generation display that breaks away from displaying limited information on flat and curved screens. However, the implementation of stretchable displays requires much more complex fabrication processes and meticulous efforts compared to traditional flat/curved displays. Here, the biaxially stretchable AM micro‐light emitting diode (LED) display on polydimethylsiloxane (PDMS) with liquid metal (LM) interconnects is reported. The pixel islands consisting of oxide TFTs and micro‐LEDs, which are fabricated on the polyimide (PI) substrate, are formed through green laser cutting and transfer to the PDMS substrate. LM interconnects integrate on the pixel island and PDMS by a lift‐off process. The oxide TFTs and micro‐LEDs comprising the 2T1C (2 TFT + 1 capacitor) pixel circuit on the PI island, along with LM interconnects, demonstrate stable electrical characteristics even under a relaxed state as well as when biaxially stretched up to 24%. For 24% stretching of display pixels with the same ratio of PI island and LM interconnects, the LM interconnects operate at 48% stretching. The combination of pixel island array and LM interconnects successfully demonstrates the implementation of a two‐axis stretchable display capable of displaying characters of “A”, “D”, “R”, and “C” through AM driving.

Comparison of four different displays for identification of select pathologic features extracted from whole slide images of surgical pathology cases

BackgroundThe establishment of minimum standards for display selection for the whole slide image (WSI) interpretation has not been fully defined. Recently, pathologists have increasingly preferred using remote displays for clinical diagnostics. Our study aims to assess and compare the performance of three fixed work displays and one remote personal display in accurately identifying ten selected pathologic features integrated into WSIs. DesignHematoxylin and eosin-stained glass slides were digitized using Philips scanners. Seven practicing pathologists and three residents reviewed ninety WSIs to identify ten pathologic features using the LG, Dell, and Samsung and an optional consumer-grade display. Ten pathologic features included eosinophils, neutrophils, plasma cells, granulomas, necrosis, mucin, hemosiderin, crystals, nucleoli, and mitoses. ResultsThe accuracy of the identification of ten features on different types of displays did not significantly differ among the three types of “fixed” workplace displays. The highest accuracy was observed for the identification of neutrophils, eosinophils, plasma cells, granuloma, and mucin. On the other hand, a lower accuracy was observed for the identification of crystals, mitoses, necrosis, hemosiderin, and nucleoli. Participant pathologists and residents preferred the use of larger displays (>30″) with a higher pixel count, resolution, and luminance. ConclusionMost features can be identified using any display. However, certain features posed more challenges across the three fixed display types. Furthermore, the use of a remote personal consumer-grade display chosen according to the pathologists’ preference showed similar feature identification accuracy. Several factors of display characteristics seemed to influence pathologists’ display preferences such as the display size, color, contrast ratio, pixel count, and luminance calibration. This study supports the use of standard “unlocked” vendor-agnostic displays for clinical digital pathology workflow rather than purchasing “locked” and more expensive displays that are part of a digital pathology system.

Recent Advances in MicroLED Displays with Integrated Image Capture

AbstractMicroLED displays afford the space for integrating more complex sensors by virtue of a smaller emitter size relative to the display's pixel area.

Anti-crosstalk device based on a Novel Micro-LED structure design

Herein, the crosstalk problem of display pixels and color subpixels is solved according to the optical design requirements of a large half-beam angle and highly uniform far-field light distribution to obtain improved display effects. A new chip micro-light emitting diode (LED) + quantum dot (QD) fluorescence mode is presented. The design optical principle uses the Monte Carlo method to prevent the light emitted from the chip from entering the QD film in adjacent pixels. Implementation is achieved by adjusting the distance between the QD film and the chip. The results are obtained by optimizing the distance between the micro-LED and the QD phosphor. When the distance between the QD fluorescent film and the chip is constant, the intensity of the light received by the QD fluorescent film decreases at increasing distances between the subpixel chips, and its contrast increases. The analyzed results suggest that anti-crosstalk micro-LED optical devices can reduce the illuminance on the receiving surface of adjacent pixels to the original 0%. Thus, the crosstalk between display pixels is effectively addressed.

70‐2: Modification of Pixel Design for NFC Antenna Integrated in LCD Panel

As a greatly pragmatic function on mobile phones and other mobile terminals, near‐field communication brings extremely convenience to people. The module designed on the back of the mobile phone terminal contains independent antenna coils, matching circuits, driver ICs and other structures. Based on BOE's proposal of a coil structure integrated in the display pixel in 2021 and preliminary verification of the communication effect, this paper proposes a revised design of the pixel coil structure to improve the communication performance of NFC coil.

38‐3: Design of Random Depolarization Films Based on Modulation Transfer Function Measurements

The random depolarization film (RDF), a polymer film doped with birefringent microparticles, solves polarization problems of displays. To design the RDF that realizes sharper images, the optimal dopant particle size and suitable display's pixel size were investigated based on modulation transfer function (MTF) measurements. The MTFs indicated that the dopant particle size of the RDF and the pixel size of the display should be larger to prevent the sharpness degradation.

10‐4: Method for Separating the Optical and Display Contributions to Spatial Resolution in Augmented Reality Displays

We demonstrate a point‐spread function (PSF) method for measuring the spatial resolution of augmented reality head mounted displays (AR HMD). Spatial resolution of HMDs is determined by optical and display performance and our method allows for separating these contributions to spatial resolution. Calculations illustrate the dependence of the HMD's PSF on the relative size and symmetry of the display pixels and optical PSF as a function of the size of target displayed. We tested our method on the Microscoft HoloLens 2 and show that the ratio of the optics to display PSF widths is 0.76.