Mura compensation is essential for maintaining the display quality. However, the large volume of Mura compensation data significantly increases memory cost and system complexity. Previous compression methods offer a certain level of compression ratio, but they are limited by degraded compensation performance in low-gray regions, blocking artifacts caused by slice clustering, and inherent limitations in achievable compression ratios. To overcome these limitations, we propose a new Mura data compression algorithm (MDC-X) that utilizes both multi-plane similarity and local similarity. The proposed method applies Differential Pulse Code Modulation (DPCM) to a reference plane and performs slice-based linear approximation for the remaining planes, thereby achieving high-efficiency model-based compression. Experimental results demonstrate that MDC-X maintains high reconstruction quality, while supporting a wide range of compression ratios, from 5:1 to 42:1, depending on the number of planes and slice sizes. Specifically, evaluations conducted on 37 diverse test panels demonstrate that MDC-X achieves an aggregate average PSNR of 60.24 dB at a 7.5:1 compression ratio, a value derived from the integrated performance across the P_0 , P_1 , and P_2 planes. In addition, the reference-plane-based reconstruction structure effectively prevents blocking artifacts caused by clustering, and the compression ratio increases proportionally as the number of planes grows. These findings show that MDC-X is a practical compression solution capable of simultaneously reducing memory cost and ensuring compensation performance in display manufacturing processes.
The accurate evaluation of energy levels is essential for optimizing the performance of organic light-emitting diode (OLED) materials. In this study, we systematically analyzed the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of small organic molecules widely used in various layers of OLED devices using cyclic voltammetry (CV). These molecules include the thermally activated delayed fluorescence (TADF) emitters 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) and 4,5-bis(carbazol-9-yl)-1,2-dicyanobenzene (2CzPN). To maximize measurement reliability, we conducted optimization studies across various environmental parameters, such as sweep direction, scan rate, material concentration, solvent, and working electrode type. As a result, we established analytical conditions that ensured a stable potential window tailored to the characteristics of the solvent and electrode, while minimizing background current interference. In particular, we successfully performed negative CV scans, which had previously been challenging to measure reliably due to various technical difficulties. This is significant, as it provides an effective and practical method for the independent and intuitive evaluation of the LUMO levels of organic materials solely through optimized electrochemical CV analysis.
Abstract Autostereoscopic displays have transformative potential in entertainment, education, and emerging fields such as humanoid robotics. However, moiré artifacts caused by interference between display pixels and optical elements severely reduce image quality and limit this application. To address this challenge, we introduce CLEAR (Chromatic-Luminance Evaluation for Artifact Reduction), a perception-driven model that integrates luminance and chromatic dimensions. The model objectively quantifies moiré visibility to enable systematic artifact reduction in lenticular autostereoscopic displays. CLEAR is calibrated using human visual experiments, enabling accurate detection of mid- to high-frequency moiré patterns. A separate observer study on 15 Blender-simulated moiré images further demonstrates that CLEAR achieves agreement with subjective ratings comparable to that of a representative S-CIELAB baseline. By leveraging this quantitative framework, we optimize lenticular lens design through simulation to identify configurations that minimize moiré visibility. Validation via ray tracing simulations and empirical observations demonstrates a strong relationship between lenticular lens geometry and moiré intensity, demonstrating the model’s utility for guiding the design of advanced autostereoscopic displays. This work advances autostereoscopic display technologies by providing practical solutions to minimize visual artifacts.
This study proposes a data voltage compensation scheme that addresses bottom-gate-to-source voltage (VBGS) differences in double-gate indium-gallium-zinc oxide (IGZO) thin-film transistors (TFTs) used in active-matrix organic light-emitting diode (AMOLED) pixel circuits. The compensation factor is derived from the pixel current equation and applied to the data voltage to correct the source voltage difference between the data writing and emission periods. To validate the approach, double-gate IGZO TFTs and diode-connected 6T1C pixel circuits were fabricated and evaluated under two bottom-gate conditions. The first ties the bottom-gate to the source and therefore can operate in depletion-mode, while the second applies a negative bottom-gate bias and can operate in enhancement-mode. The depletion-mode pixel shows a maximum current error of 35.8
Recent advancements in anomaly detection have shown significant potential across various industrial domains. However, a wide range of unpredictable defect types emerge in the real world, and anomaly images are often challenging to obtain, making traditional methods less suitable. To address this challenge, recent studies have focused on the multiclass unsupervised anomaly detection task. Nonetheless, these approaches face significant challenges owing to the difficulty in robustly handling diverse classes and defect types. We propose adaptive feature refinement anomaly detection (AFRAD), which integrates a multilayer perceptron-based stage-adaptive decoder that adaptively decodes multiscale feature maps to model broader contextual relationships. Furthermore, to minimize information loss, we introduce a convolution neural network-based focused local decoder to capture fine details at low-level dimensions and an MLP-based compensation decoder. The compensation decoder compensates for information missed by the stage-adaptive decoder and focused local decoder. This strategy improves the ability of the model to handle diverse aspects of the data, enabling robust anomaly detection. In addition, we experimentally demonstrate that the fusion of final representations enables the generation of high-quality reconstructed feature maps. Our AFRAD achieves superior performance compared with conventional reconstruction-based methodologies on various public datasets.
This study investigates ambient-light–induced image-quality degradation in optical see-through (OST) displays and presents a perceptually driven enhancement method. Luma and chroma of input images are adjusted via power-law transformations to compensate for contrast loss and chroma reduction caused by additive mixing with ambient light. The adjustment parameters were empirically derived through psychophysical experiments and modeled using ambient light level (SR,
Atomic layer deposition (ALD) heralds a paradigm-shifting revolution in atomic-scale interface engineering for semiconductor nanocrystal light-emitting diodes (SNC-LEDs), elegantly unifying colloidal quantum dots (cQDs) and metal-halide perovskite emitters through its hallmark sequential, self-limiting surface reactions—fundamentally distinguishing ALD from chemical vapor deposition (CVD), physical vapor deposition (PVD, e.g., sputtering), and solution processing (e.g., spin-coating and inkjet printing) to deliver sub-angstrom thickness mastery, defect-minimal conformality, and chemically abrupt interfaces that enable exquisite, orthogonal orchestration of energy-level alignment, charge injection/extraction dynamics, exciton confinement, and environmental resilience across intricate multilayer architectures. Ultrathin oxides (e.g., aluminum trioxide (Al2O3), zinc oxide (ZnO), titanium oxide (TiO2), magnesium oxide (MgO), and nickel oxide (NiO)) grown by ALD emerge as multifunctional interfacial constructs of unparalleled sophistication, simultaneously passivating trap states, stabilizing ligand shells, engineering charge-selective contacts, optimizing optical microcavities, and erecting diffusion barriers—seamlessly translating nanoscale chemical precision into transformative macroscopic leaps in radiative efficiency, spectral purity, and operational longevity. This review unveils trailblazing ALD and ALD-inspired frontiers—plasma-enhanced atomic layer deposition (PEALD) nitrides (e.g., aluminum nitride (AlN), hafnium nitride (HfN), and titanium nitride (TiN)), colloidal ALD (c-ALD)-like chalcogenide shells (e.g., zinc sulfide (ZnS) and cadmium sulfide (CdS)), and molecular layer deposition (MLD) organic–inorganic hybrids (e.g., alucones and titanicones)—unlocking unprecedented interfacial energetics mastery and mechanical compliance that decisively vanquish stability and charge-imbalance bottlenecks plaguing next-generation displays. Through rigorous conceptual demarcation between true ALD (vapor-phase and self-limiting) and related modifications (silylation, liquid-phase cross-linking, and vapor-phase infiltration), this mechanistically crystalline synthesis charts an interface-by-design roadmap propelling SNC-LEDs toward display-grade manufacturability, rearchitecting optoelectronics for flexible augmented reality (AR)/virtual reality (VR) displays, wearable ecosystems, and energy-efficient lighting.
Abstract The advancement of organic light-emitting diode (OLED) technology has been predicated on a fundamental understanding and precise control of molecular orientation within organic thin films. Among these phenomena, spontaneous orientation polarization (SOP), formed by the spontaneous alignment of polar organic molecules during deposition, has emerged as a critical factor influencing device performance. SOP is a macroscopic polarization phenomenon that arises from the statistically dominant orientation of molecules possessing a permanent dipole moment within an amorphous organic thin film. This alignment, which constitutes SOP, results in the formation of fixed polarization charges at the interfaces and induces the accumulation of mobile charge carriers from the adjacent layer. While SOP can facilitate charge injection by modulating interfacial energy barriers, it can also induce charge accumulation at interfaces, leading to exciton-polaron quenching, which is a key cause of reduced device efficiency and lifetime. This dual nature of SOP has made its precise control and optimization, rather than simple elimination, a central challenge in the development of high-performance OLEDs. This review discusses the mechanisms and dual impacts of SOP on OLEDs, recent control strategies via molecular, process, and device engineering, and offers a future outlook.
We propose an amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT)-based active-matrix organic light-emitting diode (AMOLED) pixel circuit that provides highly stable driving current even in the pico-ampere-range current region. The proposed circuit minimizes the stored threshold voltage ( V_TH ) loss caused by parasitic capacitors through the indirect connection of switching TFTs (SWTs) at the beginning of the emission stage, demonstrating high compensation accuracy for OLED current below 1nA. The measured results confirmed that the relative current error rate, calculated from the average current of five measured circuits, remained within a maximum of 14.99 V_TH variations in the driving TFT (DRT).
Organic light-emitting diodes (OLEDs) inherently suffer from severe optical losses, with most generated photons confined by total internal reflection. To mitigate these losses, conventional light-extraction methods rely on complex, energy-intensive fabrication using non-biodegradable materials. Thus, this study presents an eco-friendly and biocompatible strategy that combines poly(butylene adipate-co-terephthalate) (PBAT) as a biodegradable template with carboxymethyl cellulose and tannic acid (ECO-UV) films. Templates and films were fabricated through a simple, low-temperature, solution-based replication process without lithography or vacuum processes, forming irregularly distributed microstructures that enhance light scattering and suppress internal reflection. The OLEDs incorporating the ECO-UV film exhibited up to 36
Accurate prediction of large-strain mechanics in thin-film actuators is crucial for designing shape-morphing electronics such as foldable, rollable, and stretchable display modules. We present a finite element framework based on the updated Lagrangian formulation, which evaluates stress and strain on the deformed configuration at each simulation step. By continuously remapping experimentally measured, temperature-dependent material properties, such as elastic modulus, Poisson’s ratio, and density, and accommodating evolving boundary conditions from kirigami cuts, the model captures the spatio-temporal evolution of stress anreveals how interactions between neighboring, stress-inducing, localized actuating regions influence the global three-dimensional shape transformation. Simulations reproduce key phenomena, including synclastic and anticlastic curvatures, asymmetric twisting from pre-strain misalignments, and stress coupling in double- and multi-hinge configurations, with strong agreement to experiments. Time-resolved stress distributions and intermediate shape configurations offer valuable insight into the mechanisms underlying complex deformation behaviors. Because the formulation is agnostic to the specific actuation stimulus, it can be readily extended to multi-stimulus morphing systems. Overall, the framework provides a general predictive tool that links actuator layout and spatio-temporal redistribution of material parameters to the resulting 3D morphology, thus enabling virtual prototyping of adaptive display structures and other morphable thin-film devices.
Temperature variations in active-matrix organic light-emitting diode (AMOLED) displays cause noticeable changes in luminance and color, leading to degradation in overall image quality. To address this issue, this study proposes a design optimization method that locally modulates the contact-hole density around the driving thin-film transistor (TFT) within each subpixel to effectively reduce temperature-induced variations. A contact-hole refers to an opening in the interlayer dielectric that provides a vertical electrical connection between stacked metal layers. Its density was controlled to adjust the degree of low-temperature polycrystalline silicon (LTPS) dehydrogenation during annealing, thereby tuning the temperature-dependent threshold-voltage (Vth) variation. The proposed method was applied to the subpixel design of a 13-inch AMOLED panel with a tandem OLED to verify its effectiveness in controlling temperature-induced luminance variation. As a result, the color deviation was reduced by 73
This study proposes a novel driving method to address temporal response degradation observed during gray-level transi-tions under low-frequency operation in low-temperature poly-Si and oxide (LTPO) active-matrix organic light-emitting diode (AMOLED) displays. Through experimental investigation, we demonstrate that the delayed response is primarily attributed to the hysteresis behavior of the driving thin-film transistor (D-TFT), leading to a threshold voltage (V-TH ) shift and delayed recovery during black-to-white transitions (ie, gray-level transition). Moreover, the V-TH shift can distort the parasitic coupling effect during the programming phase, leading to further degradation in temporal response. To mitigate this issue, we evaluate two approaches, increasing a reset voltage and introducing short-duration high-frequency frame insertion during gray-level transitions to facilitate rapid V-TH recovery. Through this, we demonstrate that while both methods improve the luminance response, the frame insertion technique achieves superior performance particularly in luminance stability. This frame insertion method improved the first-second luminance response from 68.1 to 98.2%, while achieving this enhancement with only a 0.6% increase in power consumption through power-efficient optimization. This approach significantly enhances display performance under low-refresh-rate operation, such as in always-on display (AoD) modes.
In this paper, we propose a novel active matrix organic light-emitting diode (AMOLED) pixel circuit using amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). The proposed pixel circuit, which comprises seven TFTs and two capacitors, is capable of comprehensively and simultaneously compensating for threshold voltage ( V_TH ), mobility ( μ _n ), and subthreshold swing (SS) variations. This circuit mitigates such variations by storing additional compensation voltage in the capacitor using a constant current that depends on a previously stored voltage. The compensation process is validated through the derivation of analytical equations. Additionally, the operation of the proposed circuit is demonstrated through HSPICE. The simulation results demonstrate that the proposed circuit can maintain accurate and stable OLED current despite the presence of various variations in the electrical characteristics of TFTs. Importantly, the circuit exhibits enhanced compensation accuracy in the low gray level region, which is critical for achieving high image uniformity in AMOLED displays.
Abstract Top-emission quantum dot light-emitting diodes (QLEDs) have been extensively studied due to their potential application in augmented/virtual reality. Particularly, the impact of Fabry-Pérot resonance on top-emission QLEDs has been investigated through both experimental and theoretical studies. Additionally, multi-beam interference effects in QLED emission layers have been explored theoretically. However, previous studies predominantly rely on simplified simulations or governing equations with minor numerical corrections, often resulting in discrepancies between theoretical predictions and experimental results. Notably, a comprehensive investigation of multi-beam interference effects remains insufficient. This study aims to perform a theoretical analysis of multi-beam interference, substantiated with numerical simulations. Specifically, we examine Fabry-Pérot resonance effects and compare them with interference between upward and downward emission components in QLED layers. The findings are expected to provide insights into designing more efficient QLED architectures.
Double-gate TFTs (Thin Film Transistors) are widely used in pixel circuitry, flexible displays, biochemical and environmental sensors, and non-volatile devices like flash memory. However, limited CAD-based double-gate TFT (DGTFT) models are available for accurately simulating and optimizing these applications. Therefore, the paper presents the adaptation of the existing HSPICE (High-level Simulation Program with Integrated Circuit Emphasis) level-58 model initially crafted by the University of Florida for fully depleted silicon-on-insulator (FDSOI) technology to emulate the performance traits of double-gate amorphous indium gallium zinc oxide (a-IGZO) TFTs. The adapted double-gate a-IGZO TFT model accurately reproduces the TFTs' experimental characteristics, establishing its viability for integration into CAD tool systems and streamlining pixel circuit simulations. Additionally, the adapted level-58 FD-SOI model offers insights into the behavior of Zinc Oxide (ZnO) thin-film transistors, particularly elucidating phenomena like the 'kink effect', etc. Crucially, the performance parameters derived from the adapted models closely correlate with experimental data, enhancing the accuracy of the adapted model. In the subthreshold regime, the maximum deviation in the subthreshold slope is around 10 mV/decade. Performance metrics such as on-to-off ratio Ion/Ioff, negative bias reverse saturation current (I0), and threshold voltage (VTH) closely correspond with experimental data. There are only slight average deviations of 0.03% in the output characteristics of the adapted level-58 FD SOI model, emphasizing its increased accuracy in calibrated results.
This paper proposed a compact a-IGZO TFT-based active matrix organic light-emitting diode (AMOLED) pixel circuit driving multiple OLEDs. The pixel size was minimized using a single capacitor and field-sequential-color (FSC) driving, allowing one pixel to control two OLEDs, halving its effective size. However, these approaches constrain the threshold voltage (VTH) detection time to 1 horizontal (1H) time, and introducing subframes for FSC driving reduces 1H time compared to the conventional approach. This leads to pressing issues related to incomplete VTH sensing and the RC delay in the DATA line. Therefore, strategies to overcome these issues were also recommended. The findings revealed that the proposed circuit improves VTH detection accuracy in low gray levels by initializing the gate-source voltage of the driving TFT according to the gray level. This enhances the uniformity in low gray levels. Also, RC delay-induced nonuniformity was mitigated by extending the initialization stage to ensure the DATA line voltage stabilizes before data programming, minimizing the data storage distortion. Finally, the proposed circuit and its operation were verified through HSPICE and experimental measurements. The fabricated circuit, with a compact size of 39.3 $ \rmu $ mu m x 39.3 $ \rmu $ mu m, achieving 646 PPI, exhibited stable operation under the designed conditions.
This paper investigated the photo response behavior of amorphous indium gallium zinc oxide (a-IGZO) thin films, identifying three distinct photoconductivity types corresponding to different oxygen vacancy concentrations: Type I (low vacancy density), Type II (intermediate density), and Type III (high vacancy density). The results reveal that the photoconductive properties of a-IGZO are massively influenced by oxygen vacancy concentration, which can be precisely controlled through vacuum annealing. Type I films exhibit rapid recombination of photogenerated electron-hole pairs when illumination is removed, suggesting minimal involvement of defect states. Contrarily, Types II and III yield slower photo response and increasingly persistent photoconductivity, reflecting the growing presence of ionized oxygen vacancies that act as donor states. This demonstrates the essential impact of vacancy-induced defect levels on carrier trapping and recombination behavior. In films with low vacancy densities, defect generation under illumination was observable, while in films with higher vacancy concentrations, incident light ionizes oxygen vacancies, increasing donor state density and enhancing photoconductivity. Moreover, the observed photo response characteristics provide a useful indicator of film quality. The study's findings emphasize the role of oxygen vacancy in the electronic and optoelectronic properties of a-IGZO, offering practical guidance for implementing quality IGZO films.
