Textile Display Research Articles

Analytic modeling and validation of strain in textile-based OLEDs for advanced textile display technologies

In the IoT era, the demand for wearable displays is rapidly growing, catalyzing the advancement of research into textile-based organic light-emitting diodes (OLEDs). This growing interest stems particularly from the inherent flexibility of textile-based OLEDs1,2, allowing for seamless integration into the dynamic and interactive functionalities of cutting-edge wearable technology, alongside their superior electrical performance. The durability and mechanical robustness of these displays, especially under physical stress and deformation, are critical to their practical application and longevity. Thus, understanding and enhancing the mechanical properties of textile-based OLEDs is paramount for their successful integration into wearable technologies. However, many studies assessing the mechanical properties of OLEDs have predominantly relied on simplistic bending test outcomes determined by the radius, often neglecting or insufficiently analyzing the strain exerted on the OLEDs atop textile substrates in relation to curvature of these devices. Existing analyses typically presume pure bending, though such an assumption leads to considerable errors in strain estimations, making such approaches problematic if the goal is practical application in actual wearable display products. To address these limitations, an analytic model that includes a comprehensive energy equation is introduced, considering the stretching energy, bending energy, and shear energy of each layer composing the textile substrate. This holistic approach provides a novel formula specifically designed to calculate the top surface strain of textile substrates. Robust validation of this formula is conducted by comparing its results with strain measurements obtained from digital image correlation (DIC) and finite element analysis (FEA) outcomes from ANSYS across various bending radii (or equivalently, curvatures). The close alignment of the calculated strain values with those derived from DIC and FEA not only underscores the precision of this formula but also highlights its significant potential for enhancing the designs and functionalities of future wearable display technologies under real-world conditions.

Towards integrated textile display systems

Towards integrated textile display systems

A Stretchable, Sweat‐Resistant Electrophoretic Display Device Driven by Human‐Safe Voltage for Smart E‐Textile Application

AbstractThe demand for wearable display devices capable of real‐time information collection is growing rapidly. Among them, electrophoretic display (EPD) shows features of ultra‐low power consumption and high readability in sunlight, making them particularly suitable for wearable applications. However, due to high driving voltage and susceptibility to salt, few wearable EPD devices are reported so far. To address this, a stretchable EPD compatible with textiles is fabricated based on waterborne polyurethane. The device exhibits great performance to resist water and sweat, achieving a whiteness of 35 (Y in CIE XYZ) and a contrast ratio of 13.5 at a driving voltage of 30 V. Benefit from the device's excellent bistability and flexibility, there is no degrading to its optoelectronic performance after bending, twisting or stretching. For demonstration, an 8 × 8 matrix display is realized, showcasing that this process is suitable for wearable textile display applications.

RGB‐Color Textile‐Based Flexible and Transparent OLEDs Considering Aesthetics (Adv. Mater. Interfaces 2/2023)

Textile Displays In article number 2202114, Junwoo Lee, Kyung-Cheol Choi, and colleagues develop textile-based RGB-color transparent organic light-emitting diodes (trOLEDs) with high opto-electronic performance and mechanical reliability to improve the aesthetics of textile displays. In addition, by presenting a new optical analysis method that considers the special characteristics of textile-based trOLEDs, it is demonstrated that flexible optimization of textile trOLEDs in terms of aesthetic factors is possible.

(Invited) High-Performing Fibre Batteries at a Scalable Production

Fibre batteries are pioneering as flexible power solutions because they can be woven into textiles. Textile batteries offer a convenient and seamless way to power future wearable electronics. However, current fibre batteries are only centimetres long because longer fibre batteries are difficult to produce and they are thought to have significantly higher internal resistances that compromise electrochemical performance. Here, we show our discovery that internal resistance of fibre battery has a hyperbolic cotangent function relationship with fibre length, where it firstly decreases before leveling off as length increases. Systematic studies confirm this is true for different fibre batteries. We thus produce metres of high-performing fibre lithium-ion batteries via an optimised industrial process. Our mass-produced fibre batteries had high certified energy density based on the total weight of a lithium-cobalt-oxide/graphite full battery including packaging. Over 80% capacity can be maintained after bending for 100,000 cycles, indicating high flexibility. We show fibre batteries woven into safe and washable textile by industrial rapier loom can wirelessly charge a cellphone or power a health management jacket integrated with fibre sensors and textile display.

Water stable and matrix addressable OLED fiber textiles for wearable displays with large emission area

Organic light-emitting diode (OLED) fibers with favorable electroluminescence properties and interconnectable pixel configurations have represented the potential for wearable electronic textile displays. Nevertheless, the current technology of OLED fiber-based textile displays still leaves to be desired due to several challenges, including limited emission area and lack of encapsulation systems. Here we present a fibrous OLED textile display that can attain a large emission area and long-term stability by implementing addressable networks comprised of integrated phosphorescence OLED fibers and by designing multilayer encapsulations. The integrated fiber configuration offers decoupled functional fiber surfaces for an interconnectable 1-dimensional OLED pixel array and a data-addressing conductor. Tailored triadic metal/ultrathin oxide/polymer multilayer enables not only the oxygen/water permeation inhibition but also the controllable conductive channels of dielectric antifuses. Together with reliable bending stability, the long-term operation of OLED textiles in water manifests the feasibility of the present device concept toward water-resistant full-emitting-area fibrous textile displays.

Smart textile lighting/display system with multifunctional fibre devices for large scale smart home and IoT applications

Smart textiles consist of discrete devices fabricated from—or incorporated onto—fibres. Despite the tremendous progress in smart textiles for lighting/display applications, a large scale approach for a smart display system with integrated multifunctional devices in traditional textile platforms has yet to be demonstrated. Here we report the realisation of a fully operational 46-inch smart textile lighting/display system consisting of RGB fibrous LEDs coupled with multifunctional fibre devices that are capable of wireless power transmission, touch sensing, photodetection, environmental/biosignal monitoring, and energy storage. The smart textile display system exhibits full freedom of form factors, including flexibility, bendability, and rollability as a vivid RGB lighting/grey-level-controlled full colour display apparatus with embedded fibre devices that are configured to provide external stimuli detection. Our systematic design and integration strategies are transformational and provide the foundation for realising highly functional smart lighting/display textiles over large area for revolutionary applications on smart homes and internet of things (IoT).

High-Performance and Reliable White Organic Light-Emitting Fibers for Truly Wearable Textile Displays.

Light‐emitting fibers have been intensively developed for the realization of textile displays and various lighting applications, as promising free‐form electronics with outstanding interconnectivity. These advances in the fiber displays have been made possible by the successful implementation of the core technologies of conventional displays, including high optoelectronic performance and essential elements, in the fiber form‐factor. However, although white organic light‐emitting diodes (WOLEDs), as a fundamental core technology of displays, are essential for realizing full‐color displays and solid‐state lighting, fiber‐based WOLEDs are still challenging due to structural issues and the lack of approaches to implementing WOLEDs on fiber. Herein, the first fiber WOLED is reported, exhibiting high optoelectronic performance and a reliable color index, comparable to those of conventional planar WOLEDs. As key features, it is found that WOLEDs can be successfully introduced on a cylindrical fiber using a dip‐coatable single white‐emission layer based on simulation and optimization of the white spectra. Furthermore, to ensure durability from usage, the fiber WOLED is encapsulated by an Al2O3/elastomer bilayer, showing stable operation under repetitive bending and pressure, and in water. This pioneering work is believed to provide building blocks for realizing complete textile display technologies by complementing the lack of the core technology.

Scalable production of high-performing woven lithium-ion fibre batteries.

Fibre lithium-ion batteries are attractive as flexible power solutions because they can be woven into textiles, offering a convenient way to power future wearable electronics1-4. However, they are difficult to produce in lengths of more than a few centimetres, and longer fibres were thought to have higher internal resistances3,5 that compromised electrochemical performance6,7. Here we show that the internal resistance of such fibres has a hyperbolic cotangent function relationship with fibre length, where it first decreases before levelling off as length increases. Systematic studies confirm that this unexpected result is true for different fibre batteries. We are able to produce metres of high-performing fibre lithium-ion batteries through an optimized scalable industrial process. Our mass-produced fibre batteries have an energy density of 85.69watt hour per kilogram (typical values8 are less than 1watt hour per kilogram), based on the total weight of a lithium cobalt oxide/graphite full battery, including packaging. Its capacity retention reaches 90.5% after 500 charge-discharge cycles and 93% at 1C rate (compared with 0.1C rate capacity), which is comparable to commercial batteries such as pouch cells. Over 80 per cent capacity can be maintained after bending the fibre for 100,000 cycles. We show that fibre lithium-ion batteries woven into safe and washable textiles by industrial rapier loom can wirelessly charge a cell phone or power a health management jacket integrated with fibre sensors and a textile display.

Fully Printed, Large-Size Alternating Current Electroluminescent Device on Fabric for Wearable Textile Display

Wearable display has attracted more and more attention from academia and industry due to its potential applications in entertainment and fashion, human–computer interaction, intelligent clothing, a...

Thermochromic Silks for Temperature Management and Dynamic Textile Displays

HighlightsWearable and smart textiles are constructed by integrating embroidery technology and 5G cloud communication, showing promising applications in temperature management and real-time dynamic textile displays.Thermochromism is introduced into the natural silk to produce high-performance thermochromic silks (TCSs) through a low cost, sustainable, efficient, and scalable strategy.The interfacial bonding of the continuously produced TCSs is in situ analyzed and improved through pre-solvent treatment and is confirmed using synchrotron Fourier transform infrared microspectroscopy.Silks have various advantages compared with synthetic polymer fibers, such as sustainability, mechanical properties, luster, as well as air and humidity permeability. However, the functionalization of silks has not yet been fully developed. Functionalization techniques that retain or even improve the sustainability of silk production are required. To this end, a low-cost, effective, and scalable strategy to produce TCSs by integrating yarn-spinning and continuous dip coating technique is developed herein. TCSs with extremely long length (> 10 km), high mechanical performance (strength of 443.1 MPa, toughness of 56.0 MJ m−3, comparable with natural cocoon silk), and good interfacial bonding were developed. TCSs can be automatically woven into arbitrary fabrics, which feature super-hydrophobicity as well as rapid and programmable thermochromic responses with good cyclic performance: the response speed reached to one second and remained stable after hundreds of tests. Finally, applications of TCS fabrics in temperature management and dynamic textile displays are demonstrated, confirming their application potential in smart textiles, wearable devices, flexible displays, and human–machine interfaces. Moreover, combination of the fabrication and the demonstrated applications is expected to bridge the gap between lab research and industry and accelerate the commercialization of TCSs.

Bright‐Multicolor, Highly Efficient, and Addressable Phosphorescent Organic Light‐Emitting Fibers: Toward Wearable Textile Information Displays

AbstractFiber‐based light‐emitting devices, which can be directly integrated into daily clothes, have emerged as a next‐generation display form factor that can provide informational hyper‐connections between humans and devices. However, although various approaches have provided advanced wearability, challenges remain for visualizing information, such as high power consumption resulting from high driving voltage and low current efficiency (CE), limited brightness making information difficult to recognize, and lack of addressability for displaying information. Here, a novel fiber‐based textile display that can surmount those challenges by successfully introducing phosphorescent organic light‐emitting diodes (phOLEDs) based on a dip‐coating method and an addressable structure on cylinder‐shaped fiber is reported. The fiber phOLEDs exhibit unprecedented optoelectronic performance, including brightness, CE, and driving voltages comparable to those of conventional glass‐based OLEDs. Particularly, they show the highest CE values of 16.3, 60.7, and 16.9 cd A–1 for red, green, and blue, respectively, among results reported thus far. Also, the fiber phOLEDs with an addressable structure implementing independent pixels can be operated by the matrix‐addressable scheme. Based on unique deformability which is confirmed by flexibility tests, the performance capabilities, and addressability, letter information can be successfully visualized on daily clothes, demonstrating the potential for realizing truly wearable textile displays.

Multi-directionally wrinkle-able textile OLEDs for clothing-type displays

A clothing-type wearable display can be utilized in fashion, bio-healthcare, and safety industries as well as smart textiles for the internet of things (IoTs) and wearable devices. In response to this trend, we demonstrate a textile display that can endure the active movements of a human body. It can be applied to any kind of textile, and is durable against conditions such as rain, sweat, and washing. As a key technology for realizing the multi-directional wrinkle-able textile display, we fabricated a stress-lowering textile platform with an ultrathin planarization layer replicated from the flat surface of glass. An elastomeric strain buffer for reducing mechanical stress is also inserted into the textile platform. Here, organic light-emitting diodes (OLEDs) with red, green and blue color, thin film transistors (TFTs) fabricated at a low temperature below 150 °C, and a washable encapsulation layer blocking both gas and liquid were demonstrated on the textile platform.

Textile Based Three-Layer Robust Flexible and Stable Electrochromic Display

The textile-based electrochromic (EC) display which has been developed and presented in this article, is very compact, robust, flexible, stable, efficient, economical, and inclined to biocompatibility. The developed textile display is having only three-layer over conventional seven layers patented electrochromic structures. It is also very efficient, as it can perform its functionality even after 2500 cycles of a run and 1500 times of bending. The innovative and simplified structure of the EC device has been developed with only 3 layers, including the displaying electrode, the electrolyte container, and the counter electrode. The conductive polymer PEDOT:PSS used here as a conductive and electrochromic material, is coated on the textile substrate to perform as one side of the electrode for the asymmetric arrangement of the electrochromic device. The experiment has also been done to find out the best possible textile fabric to serve as the optimal electrochromic container. The biocompatible H3PO4 gel drenched in the semi-permeable membrane has been used as an ion transfer medium for the electrochromic display. This biocompatible ion transfer medium is sandwiched in between the electrochromic displaying electrode (PEDOT:PSS coated on fabric) and aluminum sheet (counter electrode) for making this handmade crude electrochromic display. The investigation of the EC display functioning has been observed through cyclic voltammetry within the life cycle run. The performance of the device has also been investigated in real-life conditions, by providing just ±2.0 V DC power. The other possibility is shown in our article to deposit the PEDOT:PSS compound on the textile substrate was to coat directly the yarns and then to use them into the weaving process to produce the displaying electrode. By this technique, it would also be possible to develop hybrid displays made of structures containing knitted or woven side-emitting optical fibers and our electrochromic display structure, locally.

A graphene-based electro-thermochromic textile display

Electronic textiles are rapidly emerging as key enablers for wearable electronics. Here we demonstrate fast electro-thermochromic textile displays enabled by a screen-printed, few-layer graphene ink on a cotton fabric, thus representing a breakthrough in e-textiles technology.

Textile Display with AMOLED Using a Stacked-Pixel Structure on a Polyethylene Terephthalate Fabric Substrate.

An active-mode organic light-emitting diode (AMOLED) display on a fabric substrate is expected to be a prominent textile display for e-textile applications. However, the large surface roughness of the fabric substrate limits the aperture ratio—the area ratio of the organic light-emitting diode (OLED) to the total pixel area. In this study, the aperture ratio of the AMOLED panel fabricated on the polyethylene terephthalate fabric substrate was enhanced by applying a stacked-pixel structure, in which the OLED was deposited above the organic thin-film transistor (OTFT) pixel circuit layer. The stacked pixels were achieved using the following three key technologies. First, the planarization process of the fabric substrate was performed by sequentially depositing a polyurethane and photo-acryl layer, improving the surface roughness from 10 μm to 0.3 μm. Second, a protection layer consisting of three polymer layers, a water-soluble poly-vinyl alcohol, dichromated-polyvinylalcohol (PVA), and photo acryl, formed by a spin-coating processes was inserted between the OTFT circuit and the OLED layer. Third, a high mobility of 0.98 cm2/V∙s was achieved at the panel scale by using hybrid carbon nano-tube (CNT)/Au (5 nm) electrodes for the S/D contacts and the photo-acryl (PA) for the gate dielectric, enabling the supply of a sufficiently large current (40 μA @ VGS = −10 V) to the OLED. The aperture ratio of the AMOLED panel using the stacked-pixel structure was improved to 48%, which was about two times larger than the 19% of the side-by-side pixel, placing the OLED just beside the OTFTs on the same plane.

Textiles as the Face of Modernity: Artistry and Industry in Mid-Century America

This article examines the rise of a new profession of textile designer-intermediary in mid-twentieth-century America in light of the nation’s advancements in textile production, design, display and promotion. Unlike William Morris’s nineteenth-century call for a return to handcrafts to combat the evils of the British Industrial Revolution, American textiles were promoted as the face of modernity to reflect and exploit the miracles of technology. Emerging from these developments came the ‘Super Designers’ and ‘Techno-Craftsmen’, as designers Jack Lenor Larsen and Boris Kroll referred to them, who united handcraft sensibilities with good design and mass production.1 These traits were also shared by weavers such as Anni Albers, Dorothy Liebes and Marianne Strengell, and designers of printed textiles such as Alexander Girard and Alvin Lustig. Despite an increasing reliance on mechanization, their textiles provided a human element — through texture, colour, pattern and connections to the past — to foil the threat of robotic mass production and mindless monotony. Working as corporate heads, industrial consultants, cultural ambassadors and textile collectors and connoisseurs, these designers emphasized in their work and writing the value of well-designed textiles for both visual and utilitarian purposes, collectively advancing contemporary textiles as ideal representatives of modern American design.

Textile Display for Electronic and Brain-Interfaced Communications.

Textile displays are poised to revolutionize current electronic devices, and reshape the future of electronics and related fields such as biomedicine and soft robotics. However, they remain unavailable due to the difficulty of directly constructing electroluminescent devices onto the textile-like substrate to really display desired programmable patterns. Here, a novel textile display is developed from continuous electroluminescent fibers made by a one-step extrusion process. The resulting displaying textile is flexible, stretchable, three-dimensionally twistable, conformable to arbitrarily curved skins, and breathable, and can dynamically display a series of desired patterns, making it useful for bioinspired electronics, soft robotics, and electroluminescent skins, among other applications. It is demonstrated that these displaying textiles can also communicate with a computer and mouse brain for smart display and camouflage applications. This work may open up a new direction for the integration of wearable electroluminescent devices with the human body, providing new and promising communication platforms.

유연광섬유 직물 디스플레이의 발광효과 분석 연구 - 자수방식의 직물화기법을 중심으로 -

본 연구의 목적은 직물화 조건에 유리한 유연광섬유사를 적용하여 고휘도의 발광효과를 보이는 직물 디스플레이를 개발하고 그 효율을 검증하는 것이다. 이를 위해 자수방식을 달리한 ‘Uni-pattern I’, ‘Bi-pattern I’, ‘Uni-pattern II’, ‘Bi-pattern II’의 4가지 유연광섬유 직물 샘플을 제작한 후 각각의 휘도값을 분석하였다. ‘Uni-pattern I’과 ‘Uni-pattern II’의 두 샘플은 유연광섬유와 광원의 연결방향을 한 방향으로 지정하였고, ‘Bi-pattern I’과 ‘Bi-pattern II’의 두 샘플은 유연광섬유와 광원의 연결방향을 양 방향으로 지정하였다. 4개의 샘플 모두 동일한 위치의 15 개 측정 점의 휘도값을 측정하였으며, 산술평균값을 산출하여 발광효과를 분석하였다.BR 그 결과 Green과 Red 광원을 사용한 경우, 광원과 한 방향으로 연결된 ‘Uni-pattern I’과 ‘Uni-pattern II’의 두 샘플이 광원과 두 방향으로 연결된 ‘Bi-pattern I’과 ‘Bi-pattern II’의 두 샘플에 비해 높은 발광효율을 보였다. 그러나 이러한 경향은 LED 광원 고유의 휘도가 낮은 Blue 광원에서는 나타나지 않았다. RGB 세 광원에서 가장 많은 측정점에 걸쳐 일관되게 고휘도를 보인 패턴의 순위는 ‘Uni-pattern II’ ‘Uni-pattern I’ ‘Bi-pattern I’ ‘Bi-pattern II’로 나타났다.BR

An analysis on the luminance efficiency of the machine embroidery method applied to flexible plastic optical fiber for realization of the textile display

In this research, we investigated the luminance efficiency of the computerized embroidery methods applied to flexible plastic optical fiber (POF) for realization of the textile display. Due to the nature of the flexible POF being similar to that of textile yarn, it has been possible to realize a flexible textile display by application of some adjusted fabrication methods. However, besides the simple property of flexibility, two requirements are still demanded for the flexible POF-based textile display: high luminance and the method for realization of pixels in a display. Among the fabrication methods, machine embroidery has feasibility to realize relatively higher luminance of flexible POF-based textiles through a simple procedure. The aim of this study is to evaluate of the feasibility of the embroidery method for the flexible POF-based textile display in terms of luminance, and an approach for a suitable condition in the embroidery method to realize the textile display. To do this, four embroidery methods, in which bending angles from around 90° to around 180° were applied to the flexible POF, were developed in this study. The measurement method was conducted identically on two types of POFs (flexible POFs and non-flexible POFs). The measurement points were selected in consideration of the distance from the light source and the rotation angle of the embroidery, depending on each embroidery design. Based on the resulting luminance efficiency according to the four embroidery methods, suitable conditions for the embroidery method to realize a relatively higher level of luminance for the textile display were suggested.