Three-dimensional Electrodes formation using liquid metal in micro channels for 3-axis Capacitive Force Sensor

In this study, we propose three-dimensional formation of electrodes made of liquid metal. First, three-dimensional micro channels are formed by stacking PDMS layers. Second, liquid metal, galinstan, is introduced into the channels to form electrodes and wirings. This process is crucial to develop miniaturized 3-axis capacitive force sensor. In our previous work, we proposed a ball-point-pen like capacitive sensor, however, it was difficult to be miniaturized to be mounted onto an endoscope retaining the function. We successfully manufactured 3-axis cylindrical capacitive force sensor, 5 mm in diameter and small enough to be mounted onto an endoscope. We experimentally characterized the sensor. The proposed and demonstrated sensor can be readily applicable for endoscopic palpation.