Piezoresistive stress transducer

• US 3,186,217 A
• Filed: 12/02/1960
• Issued: 06/01/1965
• Est. Priority Date: 12/02/1960
• Status: Expired due to Term

• Current Assignee: William G. Pfann
• Original Assignee: William G. Pfann
• Inventors: Pfann, William G.
• Application Number:
  US04/073,313
• Time in Patent Office: 1,642 Days
• US Class Current: 73/777
• CPC Class Codes: B23Q 15/00 Automatic control or regulation of feed movement, cutting velocity or position of tool or work programme-control G05B19/00, e.g. numerical programme-control G05B19/18
• CPC Class Codes: G01B 7/16 for measuring the deformation in a solid, e.g. by resistance strain gauge
• 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 9/04 of resistance-strain gauges
• CPC Class Codes: G01L 9/06 of piezo-resistive devices

Claims

1. A PIEZORESISTIVE STRESS GAGE COMPRISING AT LEAST TWO ACTIVE ARMS OF THE SAME PIEZORESISTIVE SEMICONDUCTOR MATERIAL AND HAVING THE SAME CONDUCTIVITY TYPE, SAID ARMS CRYSTALLOGRAPHICALLY ORIENTED IN A SINGLE GAGE PLANE SO THAT FOR A GIVEN SINGLE STRAIN DIRECTION THE PIEZORESISTIVE COEFFICIENT OF ONE OF SAID ARMS IS OPPOSITE IN SIGN TO THE PIEZORESISTIVE COEFFICIENT OF THE OTHER OF SAID ARMS, AND A WHEATSTONE BRIDGE CIRCUIT CONTAINING EACH OF SAID ARMS AS AN ACTIVE BRIDGE ARM IN A BRIDGE RELATION SUCH THAT THE