Sensor unit and sensor unit attachment method

A sensor unit that detects deformation of a measuring target object, the sensor unit comprising:

• a first sensor portion configured to detect deformation of the measuring target object;
• a second sensor portion configured to detect deformation of the measuring target object;
• and
• a first sheet, wherein the first sensor portion and the second sensor portion are attached to the first sheet,
• wherein the first sheet is attached to the measuring target object,
• wherein the first sensor portion and the second sensor portion are fixed to the measuring target object such that the measuring target object is between the first sensor portion and the second sensor portion in a first direction,
• and
• wherein a physical property value of the first sensor portion and a physical property value of the second sensor portion are changed according to a first deformation of the measuring target object,
• wherein the first sensor portion comprises a first piezoelectric body,
• and the second sensor portion comprises a second piezoelectric body,
• wherein the first piezoelectric body is a film that is stretched at least in a first uniaxial direction and that comprises polylactic acid, and
• where in the second piezoelectric body is a film that is stretched at least in a second uniaxial direction and that comprises polylactic acid,
• wherein a stretching axis of the first piezoelectric body forms an angle of 90 degrees clockwise or counterclockwise with respect to a stretching axis of the second piezoelectric body in a planar plan view of the sensor unit.