US Patent 7509884 Sensor sheet

In a sensor sheet, first electrodes (11) each covered with a pressure-sensitive resistive member and second electrodes (21) each covered with a pressure-sensitive resistive member are disposed to extend perpendicularly to each other in a plan view. A core member (40) made of a hard material is disposed over four detection regions where the first electrodes (11) and the second electrodes (21) overlap each other in a plan view. X-, Y-, and Z-axial components (Fx, Fy, Fz) of a force (F) externally applied to the sensor sheet (1) are detected on the basis of changes in the contact resistance values (R1, R2, R3, R4) corresponding the four detection regions over which one core member (40) is disposed.