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Deformable touch sensors with a high spatiotemporal resolution have recently attracted significant attention as a promising option for electronic skin and human‐machine interfaces. However, the conventional electronic matrix arrays require a large number of addressing lines and suffer from response time delay. In this study, a novel mechanically robust elastic electronic touch sensor is reported featuring only a limited number (2 or 4) of signal terminals. The sensor has a simple structure comprising an elastic spacer and two substrates with a conductive electrode of uniform resistance along the entire length of the electrode. By decoding the temporal resistance profiles from the touch sensor by using a simple simulator, the sensor can provide precise touch information such as position, instant moving speed and direction, and the trajectories of the movements. The touch actions are displayed in real‐time, regardless of whether the sensor is deformed or not. It is expected that this study will present a new approach to simplify the architecture of human‐machine interfaces. [ABSTRACT FROM AUTHOR]

In this article, we discuss the scientific research we conducted to ensure information security on concrete structures using the fiber Bragg grating method. As a result, guided by the experiences of other researchers and their results in our studies, the main hazards were identified, and the influence of temperature and deformation sensors in concrete was studied. The work determines the dependence of temperature on the optical cable and its effect on concrete deformation. It also studies the change in the internal structure of the optical fiber when exposed to concrete, and in comparison, with non-concrete optical fiber. In the experimental chapter, conducted on laboratory bench, we consider and study the signal transmission structure of an optical sensor that experiences deformation upon impact with concrete and such fibers. Graphic data was obtained using the OptiSystem program. During the process of determining the optical power of the sensors, we discovered that the higher the vibration during signal transmission, the higher the power of the optical data acquisition system unit. The results presented in this paper show the promise of fiber optics in other environments, as well as new discoveries in the construction industry and the successful use of electrical laser sensors to maintain temperature and stress in a variety of concrete structures, including cooling towers in nuclear and thermal power plants. [ABSTRACT FROM AUTHOR]

In this research, two sensor-based methods have been developed to operate industrial over-lock sewing machine, especially for loco-motor disabled person. Generally, the over-lock sewing machine is operated using foot pedal and this sensor based method eliminates the foot pedal and use alternative ways to sew garment. The method-1 uses a flextouch sensor and method-2 uses a textile sensor integrated wearable hand glove to operate the over-lock sewing machine. The seam efficiency of over-lock stitches performed using both the methods (1 & 2) has been assessed and compared with that of normal foot pedal method. Avariety of woven and knitted garments are sewed by implementing both the methods, and results are evaluated to calibrate and standardize the sensors/methods toencourage loco-motor disabled persons as self-employed sewing operators. [ABSTRACT FROM AUTHOR]

We describe ultra‐high sensitive force sensor on flat display that can detect and differentiate between feather touch and press touch or tapping. The proposed unique sensor pattern design and pressure‐sensitive material enables ultra‐high force sensitivity, multi force detection (10 points). Our force touch technology with button‐shaped bumps cover enables blind input operations and usability as good as mechanical buttons. Therefore, our technology provides reduced input errors and yield more intuitive and safedrive. In addition, the proposed novel algorithm enables an operating temperature range for automotive applications. [ABSTRACT FROM AUTHOR]

A touch screen that combines a display and a touch sensor array is a critical component enabling human-machine interaction. The progress made in flexible touch screen technologies also vigorously drives the development and application of flexible electronics in various fields. Over the past decade, there have been enormous research and development efforts on new structures and materials for touch sensors in flexible displays, especially for flexible organic light-emitting diode (OLED) displays. Herein, this review discusses the mechanics and structures of flexible touch screens, including their benefits and drawbacks. The recent advances in the structures and electrode materials (e.g., ITO, silver nanowires, metal mesh, graphene, carbon nanotubes, and conductive polymers) are reviewed, and the challenges and prospects of these technologies are also explored.

Abstract Hum-noise-based touch sensors (HumTouch) are capable of recognizing human touch on semiconductive materials using the current leaking from the finger to the surface. Thus far, calibration for these hum-noise-based touch sensors has been performed for individual users because of the individual differences in hum-driven electric currents in human bodies. However, for applications designed for unknown users, time-consuming calibration for individual users is not preferred, and a new user should be able to use the sensor immediately. For this purpose, we propose a new calibration method for HumTouch. In this method, learning datasets collected from multiple people and a few extra samples from a new user are collectively used to establish a touch localization estimator. The estimator is computed using the kernel regression method with weighted samples from the new user. For a 20 $$\times $$ × 18 cm $$^2$$ 2 paper, the mean localization error is reduced from 1.24 cm to 0.90 cm with only one sample from the new user. Hence, a new user can establish a semipersonalized localization estimator by touching only one point on the surface. This method improves the localization performance of HumTouch sensors in an easy-to-access manner.

In this study, we fabricated a textile-based touch sensor for use in smart clothing. Conductive yarns were fabricated in a sheath-core structure using PET and Cu filaments. E-textile touch sensors were woven using cotton yarns and Cu/PET filament composite conductive yarns, which were woven by varying the composition ratios (8:4, 12:7, and 16:9) of the conductive yarn used as warp and weft. The sensitivity of the e-textile touch sensors was evaluated by measuring their impedance under a load. We observed the highest sensitivity at an 8:4 ratio, owing to the largest change in impedance. Additionally, the sensitivity to touch speed, touch hold time, and touch intensity was measured considering the user's touch motion. It was confirmed that the user's touch motion affects the sensitivity of the e-textile touch sensor. This new e-textile touch sensor is expected to be useful in the field of wearable devices because it can be applied to various fabrics. Fiber only touch sensors were successfully manufactured. Touch performance was analyzed using a self-programmed program. Correlation of sensitivity with electrode composition and touch motion was analyzed. [ABSTRACT FROM AUTHOR]

Recent advancement in wearable and robot-assisted healthcare technology gives rise to the demand for smart interfaces that allow more efficient human-machine interaction. In this paper, a hydrogel-based soft sensor for subtle touch detection is proposed. Adopting the working principle of a biomedical imaging technology known as electrical impedance tomography (EIT), the sensor produces images that display the electrical conductivity distribution of its sensitive region to enable touch detection. The sensor was made from a natural gelatin hydrogel whose electrical conductivity is considerably less than that of human skin. The low conductivity of the sensor enabled a touch-detection mechanism based on a novel short-circuiting approach, which resulted in the reconstructed images being predominantly affected by the electrical contact between the sensor and fingertips, rather than the conventionally used piezoresistive response of the sensing material. The experimental results indicated that the proposed sensor was promising for detecting subtle contacts without the necessity of exerting a noticeable force on the sensor. [ABSTRACT FROM AUTHOR]

In this work, a large-scale tactile detection system is proposed, whose development is based on a soft structure using Machine Learning and Computer Vision algorithms to map the surface of a forearm sleeve. The current application has a cylindrical design, whose dimensions intend to be like a human forearm or bicep. The model was developed assuming that deformations occur only at one section at a time. The goal for this system is to be coupled with the CHARMIE robot, a collaborative robot for domestic and medical environments. This system allows the contact detection of the entire forearm surface enabling interaction between a Human Being and a robot. A matrix with sections can be configured to present certain functionalities, allowing CHARMIE to detect contact in a particular section, and thus perform a specific behaviour. After building the dataset, an Artificial Neural Network (ANN) was created. This network was called Section Detection Network (SDN), and through Supervised Learning, a model was created to predict the contact location. Furthermore, Stratified K-Fold Cross Validation (SKFCV) was used to divide the dataset. All these steps resulted in Neural Network with a test data accuracy higher than 80%. Regarding the real-time evaluation, a graphical interface was structured to demonstrate the predicted class and the corresponding probability. This research concluded that the method described has enormous potential to be used as a tool for service robots allowing enhanced human-robot interaction. [ABSTRACT FROM AUTHOR]

Hum-noise-based touch sensors (HumTouch) are capable of recognizing human touch on semiconductive materials using the current leaking from the finger to the surface. Thus far, calibration for these hum-noise-based touch sensors has been performed for individual users because of the individual differences in hum-driven electric currents in human bodies. However, for applications designed for unknown users, time-consuming calibration for individual users is not preferred, and a new user should be able to use the sensor immediately. For this purpose, we propose a new calibration method for HumTouch. In this method, learning datasets collected from multiple people and a few extra samples from a new user are collectively used to establish a touch localization estimator. The estimator is computed using the kernel regression method with weighted samples from the new user. For a 20 × 18 cm 2 paper, the mean localization error is reduced from 1.24 cm to 0.90 cm with only one sample from the new user. Hence, a new user can establish a semipersonalized localization estimator by touching only one point on the surface. This method improves the localization performance of HumTouch sensors in an easy-to-access manner. [ABSTRACT FROM AUTHOR]

Fabric Triboelectric Nanogenerators (F-TENGs) are increasingly becoming more significant in wearable monitoring and beyond. These devices offer autonomous energy generation and sensing capabilities, by replacing conventional batteries in flexible wearables. Despite the substantial effort, however, achieving high output with optimal stability, durability, comfort, and washability poses substantial challenges, so we have yet to see any practical commercial uses of these materials. This study focuses on output and investigates the impacts of mono and bimetallic composite fabric electrode configurations on the output performance of F-TENGs. Our findings showcase the superiority of bimetallic configurations, particularly those incorporating Copper (Cu) with Nickel (Ni), over monometallic (Cu only) electrodes. These configurations demonstrate remarkable results, exhibiting a maximum instantaneous voltage, current, and power density of ∼ 199 V (a twofold increase compared to monometallic configurations), ∼22 μA (a threefold increase compared to monometallic configurations), and 2992 mW/m², respectively. Notably, these bimetallic configurations also exhibit exceptional flexibility, shape adaptability, structural integrity, washability, and mechanical stability. Furthermore, the integration of passive component-based power management circuits significantly enhances the performance capabilities of the F-TENGs, highlighting the essential role of power management circuits and electrode selection in optimizing F-TENGs. In addition, we have developed a complete IoT-enabled touch sensor system using CuNi-BEF EcoFlex layered F-TENGs for precise detection of soft and hard touches. This advanced system enhances robotic functionality, enabling nuanced touch understanding essential for precision tasks and fostering more intuitive human-machine interactions. [Display omitted] • Bimetallic CuNi-BEF outperforms monometallic Cu electrodes, with a max F-TENGs voltage of ∼199 V, current of ∼22 μA, & power density of 2992 mW/m². • CuNi-BEF configurations offer superior flexibility, shape adaptability, structural integrity, & washability compared to monometallic. • Integrating passive power management boosts the performance of F-TENGs, highlighting their crucial role in optimizing device functionality. • A complete IoT CuNi-BEF EcoFlex F-TENGs sensor system enables precise touch detection, improving robotic functionality & human-machine interactions. [ABSTRACT FROM AUTHOR]

In the modern world of small-scale electronics, touch sensors unfold many numerous novel interaction techniques and other possibilities. Self-powered and flexible sensors are the future and this is where triboelectric nanogenerator-based touch sensors come. Here, surface engineering provided sufficient output performance such as 25 V, 0.4 mA/m2, and 16 mW/m2, for a Polydimethylsiloxane (PDMS) and Cellulose Acetate based TENG with micrometer separation distance. Additionally, the effect of surface modification is also quantified for better understanding. Moreover, the fabricated TENG device with micropatterned contact surfaces shows excellent tactile sensing capability of detecting and distinguishing forces of ∼0.05 N and exhibited a sensitivity of ∼3.67 V/N for small forces (

ITO thin films must have good electro-optical and mechanical characteristics to use them as integrated touch sensors for flexible OLED displays. We fabricated ITO thin films on a separation-layer-coated glass substrate under various deposition or annealing conditions, and then transferred them to cyclo-olefin polymer films to evaluate their electro-optical and mechanical characteristics. ITO films with a thickness of approximately 136 nm deposited at 250°C showed a sheet resistance of 36 Ω/□, light transmittance of 88%, and 2.4% of elongation at break. The 136 nm thick ITO films deposited at 150 °C and transferred on 50 μm thick COP film survived 500 h of 85 °C, 85% relative humidity under 180-degree bending preservation test, endured at 200,000-time repetitive bending test with a curvature radius of 1.5 mm. These high-performance ITO thin films can be applied to fabricate on-cell touch sensors for foldable OLED displays.

Many modern user interfaces are based on touch, and such sensors are widely used in displays, Internet of Things (IoT) projects, and robotics. From lamps to touchscreens of smartphones, these user interfaces can be found in an array of applications. However, traditional touch sensors are bulky, complicated, inflexible, and difficult-to-wear devices made of stiff materials. The touch screen is gaining further importance with the trend of current IoT technology flexibly and comfortably used on the skin or clothing to affect different aspects of human life. This review presents an updated overview of the recent advances in this area. Exciting advances in various aspects of touch sensing are discussed, with particular focus on materials, manufacturing, enhancements, and applications of flexible wearable sensors. This review further elaborates on the theoretical principles of various types of touch sensors, including resistive, piezoelectric, and capacitive sensors. The traditional and novel hybrid materials and manufacturing technologies of flexible sensors are considered. This review highlights the multidisciplinary applications of flexible touch sensors, such as e-textiles, e-skins, e-control, and e-healthcare. Finally, the obstacles and prospects for future research that are critical to the broader development and adoption of the technology are surveyed. [ABSTRACT FROM AUTHOR]

In this study, the adaptability of liquid metal (LM)-based transparent conductive electrodes (TCEs) to flexible substrates and their potential applications in various electronics fields were investigated. To achieve this, conventional microfabrication techniques were employed to pattern polydimethylsiloxane (PDMS) channels and introduce an Eutectic Gallium-Indium (EGaIn) LM with the aim of enhancing transmittance and reducing sheet resistance. Microfluidic channel structures with varying pitch lengths and widths were fabricated in the types of grid patterns, labeled Pattern A (2000 μm pitch, 40 μm width), Pattern B (2000 μm pitch, 80 μm width), Pattern C (200 μm pitch, 40 μm width), and Pattern D (200 μm pitch, 80 μm width. The corresponding average transmittance values for the EGaIn LM-based TCE were 90 %, 71.8 %, 61.8 %, and 43.2 % for Patterns A, B, C, and D, respectively. To illustrate the potential in touch sensor applications, resistance changes in Patterns A, B, C, and D were assessed under applied forces ranging from 0 N to 150 N, revealing resistance changes of 0.0265 Ω, 0.03617 Ω, 0.03977 Ω, and 0.11629 Ω, respectively. [Display omitted] • This research investigates the adaptability of EGaIn-based TCEs on flexible substrates for touch sensor applications. • PDMS channels were combined with EGaIn LM using microfluidics to improve optical transparency and lower sheet resistance. • Among the fabricated patterns, Pattern A demonstrated superior performance with a peak optical transmittance of 90%. • The study shows EGaIn-based LM TCEs' potential for touch sensors by measuring resistance changes with varying touch forces. [ABSTRACT FROM AUTHOR]

ITO thin films must have good electro-optical and mechanical characteristics to use them as integrated touch sensors for flexible OLED displays. We fabricated ITO thin films on a separation-layer-coated glass substrate under various deposition or annealing conditions, and then transferred them to cyclo-olefin polymer films to evaluate their electro-optical and mechanical characteristics. ITO films with a thickness of approximately 136 nm deposited at 250°C showed a sheet resistance of 36 Ω/□, light transmittance of 88%, and 2.4% of elongation at break. The 136 nm thick ITO films deposited at 150 °C and transferred on 50 μm thick COP film survived 500 h of 85 °C, 85% relative humidity under 180-degree bending preservation test, endured at 200,000-time repetitive bending test with a curvature radius of 1.5 mm. These high-performance ITO thin films can be applied to fabricate on-cell touch sensors for foldable OLED displays. [ABSTRACT FROM AUTHOR]

We report the development of a novel soft body touch sensor capable of measuring contact force along its length. The sensor can be embedded in soft objects and on curved surfaces for smart furniture, interactive electronics, and general robotics applications. The sensor uses pneumatic transduction principle and achieves both high sensitivity and impact loading tolerance. The development is motivated by the needs of consumer electronics industries for smart furniture and interactive toys. The current work fills a gap of existing soft-bodied touch sensors. The main sensor body is completely polymeric and contains no conductive or semiconducting material elements. It exhibits high pass frequency response to reject common mode contact forces or shape variations. The central question addressed by this paper is dynamic behavior of this sensor under normal and impact touch force. In this study we developed a theoretical model for the sensor output and validated with experimental measurements. We modeled sensor behavior under two operational regimes of different unloading speed. Depending on the rate of change, the sensor could be in force limited relaxation mode or elastic relaxation (free relaxation) mode. Measurements have been performed to capture time constants of occupant behavior in a smart cushion application.

Along with the invention of portable devices, such as smartphones and tablets, computerbased touch screen sensor-assistive technologies have become significantly more affordable than traditional tactile graphics. The sensor panel in these technologies allows users to receive visual and auditorial responses via interaction with the device. However, visually impaired individuals (with a lack or loss of ability to see) will not find visual responses useful when using tablets or smartphones. Therefore, in this paper we propose a system that helps visually impaired people comprehend information on electronic devices with the help of auditory action feedback. We develop a multimedia system for sound production from a given image via object detection. In this study, YOLO (You Only Look Once) is used in object detection for sonification. A pretrained model is used; thus, a wider range of object classification can be identified. The system generates the corresponding sound when an object on the sensor screen is touched. The purpose of our research is to aid visually impaired people to perceive information of a picture shown on the device by touching the detected object. The device was tested by simulating visually impaired people by blindfolding people with normal vision, who filled out questionnaires on its performance. The results indicate that most of the users found that the sound presented by the device was helpful for telling them what the shown image was. [ABSTRACT FROM AUTHOR]

A novel Radio Frequency Identification (RFID) based sensor supporting touch detection and localization features is proposed in this work. The formulated sensor leverages chipless variant of RFID technology for the design of a passive fully-printable frequency domain-based sensor-incorporated tag. The sensor is composed of square resonators arranged in a peculiar fashion laid down across a $3\times2$ grid. The proposed sensor incorporated-tag readily keeps track of human-digit position, allowing for tracking of finger-swipes which, in turn, can potentially be used for recognition of unlock patterns and security codes. Performance of the sensor is analyzed using its Radar Cross Section (RCS) response observable in the spectral domain. Each constituent resonant-element making up the sensor resonates at a single frequency represented by a distinct dip in the RCS response. The spectral dip drifts well outside of its allocated band upon occurrence of a touch event. A functional prototype of the sensor tag is fabricated on a 0.508 mm thick Rogers RT/Duroid® 5880 laminate is scrutinized of its electromagnetic performance. The sensor possesses a compact physical footprint equal to 45 mm $\times55$ mm. The obtained results solidify the suitability of the proposed sensor for deployment in secure access control settings prevalent in smart cities and connected home applications.

Recent advancement in wearable and robot-assisted healthcare technology gives rise to the demand for smart interfaces that allow more efficient human-machine interaction. In this paper, a hydrogel-based soft sensor for subtle touch detection is proposed. Adopting the working principle of a biomedical imaging technology known as electrical impedance tomography (EIT), the sensor produces images that display the electrical conductivity distribution of its sensitive region to enable touch detection. The sensor was made from a natural gelatin hydrogel whose electrical conductivity is considerably less than that of human skin. The low conductivity of the sensor enabled a touch-detection mechanism based on a novel short-circuiting approach, which resulted in the reconstructed images being predominantly affected by the electrical contact between the sensor and fingertips, rather than the conventionally used piezoresistive response of the sensing material. The experimental results indicated that the proposed sensor was promising for detecting subtle contacts without the necessity of exerting a noticeable force on the sensor.

In this work, a large-scale tactile detection system is proposed, whose development is based on a soft structure using Machine Learning and Computer Vision algorithms to map the surface of a forearm sleeve. The current application has a cylindrical design, whose dimensions intend to be like a human forearm or bicep. The model was developed assuming that deformations occur only at one section at a time. The goal for this system is to be coupled with the CHARMIE robot, a collaborative robot for domestic and medical environments. This system allows the contact detection of the entire forearm surface enabling interaction between a Human Being and a robot. A matrix with sections can be configured to present certain functionalities, allowing CHARMIE to detect contact in a particular section, and thus perform a specific behaviour. After building the dataset, an Artificial Neural Network (ANN) was created. This network was called Section Detection Network (SDN), and through Supervised Learning, a model was created to predict the contact location. Furthermore, Stratified K-Fold Cross Validation (SKFCV) was used to divide the dataset. All these steps resulted in Neural Network with a test data accuracy higher than 80%. Regarding the real-time evaluation, a graphical interface was structured to demonstrate the predicted class and the corresponding probability. This research concluded that the method described has enormous potential to be used as a tool for service robots allowing enhanced human-robot interaction.

Flexible capacitive‐type touch sensors have significant potential in robotics, foldable displays, and wearable electronics. However, the general parallel‐plate structure of these sensors unintentionally changes initial values and sensitivity in various situations, such as in electromagnetic interference (EMI) and bending. In the present study, a double side EMI‐shielded bending‐insensitive capacitive‐type touch sensor is proposed with a linear response over a wide detection range. The device has a novel design that includes double‐sided silver nanowires (AgNWs) embedded on the surface of pyramidal‐polyurethan sponge (AeSoPS) facing the opposite direction. The double‐sided AeSoPS structure offers various advantages, such as bending‐insensitive property, EMI shielding, and linearity and detection range improvement. The fabricated device exhibits excellent linearity (R2 = 0.999) up to 700 kPa, bending‐insensitive property on rigid (up to a radius of curvature of 0.7 mm) and soft surfaces, and accurate pressure measurement with superior EMI shielding effectiveness of 99.9% attenuation from EMI (30 dB within a broad frequency range from 0.5 to 12 GHz). Therefore, the developed sensor with improved performance is promising for use in flexible touch sensors, as it offers reliable sensing functions and EMI protection in various environments. [ABSTRACT FROM AUTHOR]

Spin-coated chalcostibite CuSbS 2 thin films (≈500 nm thick) were fabricated and the influence of the drying temperature on the structural, morphological, optical and thermoelectric properties of the films was investigated. Crystalline phase-pure chalcostibite has been obtained for the films dried at 180 °C and 210 °C, while below 180 °C these films are partially amorphous. Surprisingly, at drying temperature of 240 °C, a Cu x S secondary phase appeared. The increase of the drying temperature leads to the increase of the particle size and the decrease of the optical band gap, which is interesting for optoelectronic applications. The highest power factor value was achieved for the film dried at 210 °C, due to the inexistence of secondary phases, which allowed realizing a stable thermoelectric touch sensor with a V signal / noise of 5. In addition, this film was tested as a photovoltaic (PV) device and a power conversion efficiency (PCE) of 0.030% with an open-circuit voltage (V OC) of 0.36 V, a short-circuit current density (J SC) of 0.278 mAcm−2 and a fill factor (FF) of 0.27 were obtained. Therefore, this work evidences a pathway toward developing bi-functional devices with simultaneously thermoelectric touch sensor and photovoltaic functions. [Display omitted] • Bi-functional CuSbS 2 thin films prepared by spin coating. • Thermoelectric and photovoltaic properties of the CuSbS 2 films. • CuSbS 2 films exhibit a Seebeck coefficient of 315 ± 2 μV K−1. • Thermoelectric touch sensor properties with a V signal / Vnoise ratio of 5. [ABSTRACT FROM AUTHOR]

The novel solid and hollow ZnO nanorods were prepared by chemical synthesis approach. The hollow ZnO NRs show a large optical band gap as compared to the solid ZnO NRs which is attributed to quantum confinement effect. The unique emission spectra of hollow ZnO NRs show an exceptional ability for visible emission as compared to solid ZnO NRs owing to unique hollow structure, which enhanced multiple scattering. The piezoelectric potential of hollow nanorod shows about 3.75 times higher peizopotential than the solid nanorods with length (a = 200 nm) and height (h = 1000 nm). The piezoelectric potential was found to be increased with the height of nanorod with a fixed length. Interestingly, the piezoelectric potential increases with decreasing wall thickness in hollow nanorod. The hollow ZnO NRs-based touch sensor shows five times higher piezoelectric response as compared to the solid ZnO NRs. These results provide valuable information for future studies aimed at improving the piezoelectric properties of hollow nanostructures for potential applications in energy harvesting and sensing. [Display omitted] • Solid and hollow ZnO nanorod (NR) was prepared by easy and cost-effective chemical synthesis approach. • The piezoelectric potential of hollow NR shows about 3.75 times higher peizopotential than the solid NR • Piezoelectric potential increases with decreasing wall thickness in hollow NR. • The hollow ZnO NRs-based touch sensor shows five times higher piezoelectric response as compared to the solid ZnO NRs. • The hollow ZnO NRs shows efficiently use as bending sensors. [ABSTRACT FROM AUTHOR]

At present, tactile sensor technology is the only solution to measure the pressure and contact area of two solid in normal contact. In this study, the sensing characteristics of a taxel inside a flexible tactile sensor were investigated for accurate contact pressure measurements with the tactile sensors. First, a tactile sensor with 64 taxels was designed and manufactured using the microfabrication techniques. Then, an electronic scanning circuit was designed to acquire the resistance change of the tactile sensor during the loading and unloading. A particular taxel was selected inside the tactile sensor to reveal the static and dynamic characteristics of the sensor. Two custom-built experimental setups were realized for the measurements. In the first experimental setup, the static characteristics of the taxel such as the repeatability, hysteresis, sensitivity and time drift were measured. Moreover, the physical sensing mechanism of the piezoresistive sensors was discussed to find the span of the force measurement. The accuracy of the taxel was found to be 5.5%. In the second experimental setup, the frequency response of the sensor was revealed for a frequency band of 0.1Hz to 40Hz. The gain of the taxel was not flat in the measured frequency band and might be used carefully in the dynamic load range after accurate calibration. Moreover, it was found that within a 48 ± 27µsec, the sensor was responsive to the impact loading using an another test set-up.

Many modern user interfaces are based on touch, and such sensors are widely used in displays, Internet of Things (IoT) projects, and robotics. From lamps to touchscreens of smartphones, these user interfaces can be found in an array of applications. However, traditional touch sensors are bulky, complicated, inflexible, and difficult-to-wear devices made of stiff materials. The touch screen is gaining further importance with the trend of current IoT technology flexibly and comfortably used on the skin or clothing to affect different aspects of human life. This review presents an updated overview of the recent advances in this area. Exciting advances in various aspects of touch sensing are discussed, with particular focus on materials, manufacturing, enhancements, and applications of flexible wearable sensors. This review further elaborates on the theoretical principles of various types of touch sensors, including resistive, piezoelectric, and capacitive sensors. The traditional and novel hybrid materials and manufacturing technologies of flexible sensors are considered. This review highlights the multidisciplinary applications of flexible touch sensors, such as e-textiles, e-skins, e-control, and e-healthcare. Finally, the obstacles and prospects for future research that are critical to the broader development and adoption of the technology are surveyed.

The absence of standardized methods of the visible defects quantification has induced inconsistent results in quality assurance of OLED displays. Herein, an effective quantification method for evaluating horizontal line defects by interference of flexible OLED and touch sensor were proposed and a specific contrast sensitivity (CS) levels below 1.0 was established as meaning "invisible defect". [ABSTRACT FROM AUTHOR]

The innovative design of fully differential analog front end is swhich is the parasitic capacitance of a touch sensor is approximately 60% higher than a conventional smartphone. The newly developed touch sensor controller shows approximately 40 % higher SNR than a commercialized flagship smartphone, which is defined with the noise of peak to peak value in the touch signal on the zebra pattern display. [ABSTRACT FROM AUTHOR]

We describe ultra‐high sensitive force sensor on flat display that can detect and differentiate between feather touch and press touch or tapping. The proposed unique sensor pattern design and pressure‐sensitive material enables ultra‐high force sensitivity, multi force detection (10 points). The force as low as 25g comparable to make force of keyboards can be detected. The proposed technology provides on‐screen keyboard with extremely good performance for dual screen products. Moreover, with integrated force function, we can realize adaptive input interface on display not only the keyboard but also drawing pads, control boards and musical instruments. [ABSTRACT FROM AUTHOR]

Touch is a general term to describe mechanical stimuli. It is extremely difficult to develop touch sensors that can detect different modes of contact forces due to their low sensitivity and data decoupling. Simultaneously conducting tactile and slip sensing presents significant challenges for the design, structure, and performance of sensors. In this work, a highly sensitive sandwich-structured sensor is achieved by exploiting the porosity and compressive modulus of the sensor's functional layer materials. The sensor shows an ultra-high sensitivity of 1167 kPa -1 and a low-pressure detection limit of 1.34 Pa due to its considerably low compression modulus of 23.8 Pa. Due to this ultra-high sensitivity, coupled with spectral analysis, it allows for dual-mode detection of both tactile and slip sensations simultaneously. This novel fabrication strategy and signal analysis method provides a new direction for the development of tactile/slip sensors., (© 2024 Wiley‐VCH GmbH.)

With the development of light microscopy, it is becoming increasingly easy to obtain detailed multicolor fluorescence volumetric data. The need for their appropriate visualization has become an integral part of fluorescence imaging. Virtual reality (VR) technology provides a new way of visualizing multidimensional image data or models so that the entire 3D structure can be intuitively observed, together with different object features or details on or within the object. With the need for imaging advanced volumetric data, demands for the control of virtual object properties are increasing; this happens especially for multicolor objects obtained by fluorescent microscopy. Existing solutions with universal VR controllers or software-based controllers with the need to define sufficient space for the user to manipulate data in VR are not usable in many practical applications. Therefore, we developed a custom gesture-based VR control system with a custom controller connected to the FluoRender visualization environment. A multitouch sensor disk was used for this purpose. Our control system may be a good choice for easier and more comfortable manipulation of virtual objects and their properties, especially using confocal microscopy, which is the most widely used technique for acquiring volumetric fluorescence data so far.

This paper presents the results from the characterization of pneumatic touch sensors (sensing bulbs) designed to be integrated into myoelectric prostheses and body-powered prostheses. The sensing bulbs, made of silicone, were characterized individually (single sensing bulb) and as a set of five sensors integrated into a silicone glove. We looked into the sensing bulb response when applying pressure at different angles, and also studied characteristics such as repeatability, hysteresis, and frequency response. The results showed that the sensing bulbs have the advantage of responding consistently to pressure coming from different angles. Additionally, the output (pneumatic pressure) is dependent on the size of interacting object applied to the sensing bulb. This means that the sensing bulb will give higher sensation when picking up sharper objects than blunt objects. Furthermore, the sensing bulb has good repeatability, linearity with an error of 2.95± 0.40%, and maximum hysteresis error of 2.39± 0.17% on the sensing bulb. This well exceeds the required sensitivity range of a touch sensor. In summary, the sensing bulb shows potential for use in prosthetic hands. [ABSTRACT FROM AUTHOR]