Patent ID: 7234359

Claim:
A semiconductor force sensor comprising: a semiconductor force sensor element including a diaphragm section having a converting section for converting a change in a force into a change in an electric signal by piezoresistive effect; force transmitting means for applying the force to be measured to said diaphragm section of said semiconductor force sensor element, said force transmitting means being constituted by a sphere having rigidity; and a force transmitting means positioning structure having an opposed wall section spaced from said diaphragm section and arranged to face said diaphragm section, for positioning and arranging said force transmitting means so that said force transmitting means is brought into direct contact with a central portion of said diaphragm section, wherein a through hole passing through said opposed wall section in a direction toward said diaphragm section is formed in said opposed wall section of said force transmitting means positioning structure at a position facing said central portion of said diaphragm section; said through hole is so shaped that a part of said sphere faces an outside of said opposed wall section therethrough and receives a part of a remainder of said sphere so that said sphere can move only in a direction orthogonal to said diaphragm section and can rotate on said central portion of said diaphragm section; and said through hole comprises: a first through hole portion located on a side of the diaphragm section and at a position corresponding to a lower half of said sphere: a second through hole portion located on a side of said outside; and a third through hole portion located between said first through hole portion and said second through hole portion; and said first through hole portion has a constant diameter size slightly larger than a diameter of said sphere, said second through hole portion has a constant diameter size allowing said part of said sphere to be exposed to said outside from said second through hole portion, and said third through hole portion is so shaped that a diameter size thereof decreases more toward said second through hole portion from said first through hole portion along an outer surface of said sphere.