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Micro-machined accelerometer with composite material springs

  • US 5,134,881 A
  • Filed: 06/01/1990
  • Issued: 08/04/1992
  • Est. Priority Date: 06/22/1986
  • Status: Expired due to Fees
First Claim
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1. An improved spring structure in a micro-machined transducer having a support frame and a sensing mass, where said sensing mass is at least partially supported from said support frame via at least one E-shaped leaf spring structure, said spring structure defined by a base and three legs including two outer legs and an inner leg, each of said three legs being connected to said base at one end, said two legs connected to said frame at their other ends, said inner leg connected to said mass at its other end, and wherein said transducer is fabricated by etching of a semi-conductor wafer which has been doped with a dopant of one type, the improvement comprising,said base characterized by a coefficient of stiffnes substantially greater than that of said legs, andsaid base of said spring structure being fabricated of semi-conductor material and having an impurity diffused therein of an opposite type from that of which said semi-conductor wafer was doped and wherein said legs of said spring structure are each a composite structure of a base layer of semi-conducting material, a conducting layer and an insulating layer placed between said conducting layer and said semi-conducting material, said legs each characterized by a thickness which is small compared to the thickness of said base.

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