silver nanowire (AgNW)-poly(3,4-ethylene dioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) composite transparent flexible electrodes with 96% transmittance at 550 nm. [19] Nevertheless, current techniques for high transparency electrodes require cleanroom fabrication conditions, limiting their successful use in commercial products. Furthermore, some of them still blocks 10%-3% light intensity during the visible spectrum, [11,24] indicating the need for extra power consumption to maintain the display performance compared to their counterparts without touch panels installed, which shortens battery's lifetime for portable smart devices, giving rise to unpleasant user experience.In this work, to achieve ultrahigh transparency while maintaining low material cost and a simple fabrication process, an electrical impedance tomography (EIT)-based technique is presented.EIT is a low-cost and easy-to-implement detecting technology that allows real-time imaging. [25][26][27] In previous works, EIT techniques have been applied in diverse applications. In 2013, Cao and Xu applied Calderon's method to a chest-like sensing region and utilized a direct algorithm for image reconstruction. [28] They successfully reconstructed a male normal breath chest image with a 16-electrode system. In the same year, Tawil et al. proposed an impedance measurement-based artificial skin for robotics. The artificial skin was constructed using four different layers. The top layer was made of soft suede. The second layer was a highly conductive fabric. The third was a flexible carbon-loaded layer, with 19 chromium-plated brass eyelets electrodes located at its edge. The bottom layer was made of a 5 mm thick open-cell polyurethane foam. In their work, the LogitBoost algorithm was used to classify the modality of eight different touch events (tap, pat, push, stroke, scratch, slap, pull, and squeeze), the accuracy can reach 71%. [29] In 2015, Zhang et al. proposed a wearable armband sensor (Tomo [30] ), which used an eight evenly spaced copper electrodes based structure and the support vector machine (SVM) algorithm to recognize eleven hand gestures, achieving an accuracy of 96.6%. In 2018, Russo et al. [31] proposed a 16-electrode-based three-layered tactile sensor. The top is a piezoresistive fabric layer with high resistance. The second layer is a honeycomb mesh and the bottom layer is based on highly conductive fabric material. By employing a quadratic discriminant analysis (QDA), the position recognition error of this sensor ranges from 1 to 10 mm, depending on the contact locations.In traditional touch interfaces, electrodes will block the light intensity of the display, so extra power is required to maintain the display performance. In this article, an eight-electrode electrical impedance tomography system for touch location detection is proposed to improve the transmittance. The electrodes are settled at the edge of the touch panel and a machine learning algorithm is used to perform the regression process. This system can achieve almost 1 mm m...

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Nowadays, electronic devices are taking over the market and touch panel is a necessary part, among which capacitive touch panel has greater development potential and development space because of its high transparency, multitouch support and low cost. Electrical impedance tomography (EIT) is a technology with the goal of reconstructing tissue image with impedance distribution, which can realize the goal of accurate measurement and maintaining the original characteristics of the medium to the greatest extent at the same time. In this paper, we use EIT‐based approach to achieve a large area touch perception imaging system with high light transmittance, which is to obtain the distribution of the permittivity of the touch penal by just detecting the impedance of the electrode scattered around the panel. We use Sensitivity theory to solve the mapping problem between the permittivity distribution and the signal collected by the electrode in the EIT problem. Besides, we innovatively combine LBP with Landweber algorithm to achieve high precision and fast imaging of touch area, which greatly reduces the discomfort caused by inverse problem in EIT method.

In this article, we propose a new sensor architecture, in which electrodes are settled at the edge of the touch panel, ensuring a very high optical transmittance. The touch event detection relies on electrical capacitance tomography (ECT) technique. The presented technique provides a feasible means to boost the optical transmittance of the touch panel layer while maintaining touch detection accuracy.

In traditional touch panels, electrodes are settled on or above the surface of displays, weakening the optical transmittance, hence resulting in high power consumption of the display for providing customers satisfied visual experience, giving rise to reduced battery's lifetime which brings users inconvenience. To address this issue, in this article, we propose a new sensor architecture, in which electrodes are settled only at the edge of the touch panel, ensuring a very high optical transmittance. The touch event detection relies on electrical capacitance tomography (ECT) technique, through which 2-dimensional location recognition is achieved, indicating the presented technique provides a feasible means to boost the optical transmittance of the touch panel layer.