| CPC B25J 13/082 (2013.01) [G01N 3/40 (2013.01)] | 5 Claims |

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1. A pressure sensor comprising:
a base having a mounting surface;
an elastic member mounted on the mounting surface and forming a dome shape including a convex curved surface;
a first pressure-sensitive element placed in a position between the mounting surface and the elastic member and corresponding to a vertex of the convex curved surface and outputting a first detection signal by sensing pressure;
a second pressure-sensitive element placed in a position between the mounting surface and the elastic member and corresponding to a peripheral portion of the convex curved surface and outputting a second detection signal by sensing pressure; and
a calculator performing a calculation on the first detection signal and the second detection signal, wherein
the calculator measures hardness of an object based on a ratio R1-1/2 and a ratio R2-1/2, and the ratio R1-1/2 is a ratio between the first detection signal and the second detection signal when the object is pressed against the elastic member with a first load, and
the ratio R2-1/2 is a ratio between the first detection signal and the second detection signal when the object is pressed against the elastic member with a second load larger than the first load.
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