Abstract
This paper describes an experimental study on the deformation of an aluminum plate fixed by adhesive to a flexible printed circuit (FPC), which is a laminated structure composed of polyimide resin, copper leaf and adhesive. The deformation was measured by holographic interferometry using a compensation method for interferometric fringes. For example, when the thermal expansion coefficient of the aluminum plate differs from the equivalent thermal expansion coefficient of the FPC, the aluminum plate has an out-of-plane deformation. The thermal deformation caused by temperature changes can be eliminated by controlling the volume of copper leaf so that the thermal expansion coefficients are equal. The aluminum plate also has an out-of-plane deformation due to expansion and contraction of the FPC caused by humidity changes. This deformation can be eliminated by covering the polyimide of the FPC against moisture.
