Residual Stress Measurement of Adhesive Layer by Polarized Laser.

Optical birefringence is measured by a high-frequency modulation method using a photoelastic modulator and polarized laser. This measurement method has the high sensitivity required to measure very small birefringence. The distributions of optical birefringence corresponding to stress distributions are measured for a glass plate with notches and a bonded glass plates with epoxy resin. The residual stress caused by the bonding process is evaluated.