Graphene-Based Three-Dimensional Capacitive Touch Sensor for Wearable Electronics

Abstract

The development of input device technology in a conformal and stretchable format is important for the advancement of various wearable electronics. Herein, we report a capacitive touch sensor with good sensing capabilities in both contact and noncontact modes, enabled by the use of graphene and a thin device geometry. This device can be integrated with highly deformable areas of the human body, such as the forearms and palms. This touch sensor detects multiple touch signals in acute recordings and recognizes the distance and shape of the approaching objects before direct contact is made. This technology offers a convenient and immersive human-machine interface and additional potential utility as a multifunctional sensor for emerging wearable electronics and robotics.

Significance of Nanomaterials in Wearables: A Review on Wearable Actuators and Sensors

“…For example, Figure 8a,b shows a resistive pressure sensor based on a patterned elastic microstructure. [151] In order to improve the pressure sensitivity, the use of high deformable dielectric material or the designing of a dielectric material into an ideal structure like porous microstructures can be a good solution and can improve the response time due to its reduced viscoelastic deformation. Notably, the sensor displayed a high linear sensitivity of 8.5 kPa −1 from 0 to 12 kPa (Figure 8c).…”

UV Laser‐Induced Polyimide‐to‐Graphene Conversion: Modeling, Fabrication, and Application

“…After the LIG electrodes are formed, the un‐converted PI film acts as a dielectric layer between the two electrodes. When the object, such as a human hand, approaches, the charge distribution on the graphene electrodes is correspondingly altered by the surface charge on human skin, resulting in a change in the capacitance . Thus, the motion of close‐by objects can be detected by characterizing the capacitance variation.…”

Laser‐Patterned Copper Electrodes for Proximity and Tactile Sensors

“…It successfully identifies the position of direct contact. In addition, higher resolution of contact area contour mapping can be achieved by increasing the size of the sensing matrix and decreasing the pitch between adjacent parallel electrodes . These can be all readily realized through reprogramming the laser scanning trajectory on computer.…”

“…Generally, various candidate transduction methods for tactile and proximity sensing can be used, including piezoresistance, capacitance, piezoelectricity, etc . Among sensors based on aforementioned transduction methods, capacitive sensors for tactile and proximity sensation are highlighted with their simple structure requirement to form a capacitor (sandwich configurations) and effective prevention of short circuiting among the conductive structures within the sensors . Capacitance enabled proximity and tactile sensing works on the principle of interaction between human body and strong fringing electric field generated by the sensor .…”