Semiconductor force sensor

• US 7,360,440 B2
• Filed: 06/15/2007
• Issued: 04/22/2008
• Est. Priority Date: 04/12/2002
• Status: Expired due to Term

• Current Assignee: Hokuriku Electric Industry Company Limited
• Original Assignee: Hokuriku Electric Industry Company Limited
• Inventors: Motoki, Yoshimitsu, Sawamura, Hiroyuki, Hirose, Shigeru, Ando, Masato
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US11/763,844
• Publication Number:
  US 20070234827A1
• Time in Patent Office: 312 Days
• Field of Search: 737/77
• US Class Current: 73/777
• CPC Class Codes: G01L 1/18 using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
• CPC Class Codes: G01L 1/2231 the supports being disc- or ring-shaped, adapted for measuring a force along a single direction

Abstract

A semiconductor force sensor capable of preventing a diaphragm part from being broken and accurately measuring a force applied thereto in a direction orthogonal to the diaphragm part, wherein a force transmitting device for applying a measured force to the diaphragm part of a semiconductor force sensor element is formed of a sphere having a rigidity, and a through hole passing through an opposed wall part toward the diaphragm is formed in the opposed wall parts at a position opposed to the center part of the diaphragm part so that a part of the sphere can face the outside of the opposed wall part and stores a part of the remaining part of the sphere to allow the sphere to be moved only in a direction orthogonal to the diaphragm part and rotated on the center part of the diaphragm part.

Claims

1. 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;

a side of said diaphragm section on which said sphere is located is covered with a gel-like protective agent having electrically insulating property; and

penetration of said gel-like protective agent is so defined that said sphere pushes away said gel-like protective agent on said diaphragm section to substantially come in direct contact with said central portion of said diaphragm section.