Patent ID: 9383277
Filing Date: 2016-07-05
CPC Classification: G01L

Claim Text:
1. A force sensor comprising: a supporting substrate; an annular detector which is disposed above the supporting substrate; a columnar body which extends upward from a central part of an upper surface of the supporting substrate; a flexible connection member which connects the columnar body with the annular detector; detection elements, each of which outputs a measurement value according to displacement of the annular detector with respect to the supporting substrate; and a detection circuit which detects an exerted external force on the basis of the measurement value; the force sensor having such functions that when an external force is exerted on the annular detector in a state that the supporting substrate is fixed, the flexible connection member undergoes deflection, by which the annular detector gives displacement to the supporting substrate and the detection circuit detects the external force on the basis of change in the measurement value resulting from the displacement, and the force sensor further comprising: an external protrusion portion which protrudes further outside from an outer circumferential part of the annular detector; and a displacement control portion which is fixed at a position opposing the external protrusion portion on the supporting substrate; wherein, when a magnitude of the exerted external force is within a predetermined tolerance, a vertical clearance is kept between a lower surface of the external protrusion portion and an upper surface of the displacement control portion, and when a magnitude of the exerted external force is in excess of the tolerance, the lower surface of the external protrusion portion is brought into contact with the upper surface of the displacement control portion, thereby controlling displacement of the annular detector, and the detection elements are constituted with capacitive elements having fixed electrodes which are fixed on the upper surface of the supporting substrate and displacement electrodes which are formed at positions opposing the fixed electrodes on a lower surface of the annular detector.