Printed circuit board with integral strain gage

Abstract

A method for strain measurement measures strain in a printed circuit board having an integral strain measurement layer. The strain measurement layer includes an insulating layer having a top surface and a bottom surface, a strain sensitive layer of metallic foil adhered to the top surface of the insulating layer for measuring strain associated with the printed circuit board, and a copper coating disposed on the strain sensitive layer of metallic foil.

1 . A method for strain measurement on a printed circuit board comprised of a plurality of layers wherein at least one of the plurality of layers is a strain measurement layer comprising of an insulating layer and a strain sensitive metallic foil adhered to the insulating layer for measuring strain associated with the printed circuit board, comprising measuring strain associated with the strain sensitive metallic foil.  
   
   
       2 . The method of  claim 1  further comprising locating an area of high stress based on the strain.  
   
   
       3 . The method of  claim 1  wherein the area of high stress is associated with solder connection failure in the printed circuit board.  
   
   
       4 . The method of  claim 2  further comprising modifying a manufacturing process based on location of the area of high stress.