一种散光图象双折射相移的方法

由Pindera等提出了等达因法导出了平面问题的三个应力分量，可以非破坏性测取受力物体内部的应力状态，是一种有效的光测技术，应力分量与等达因条纹级次的导数相关，为得到具有高测试精度的应力分量在等达因条纹测试中引入了双折射相移技术，文中提出了一种在散光激光入射光路中用加入一可调偏振片和一可调1／4波片实现散光图象双折射相移的方法，该方法设备简单，能保证总体光强的一致性。

A Method of Birefringence Phase Shift for Astigmatism Patterns

The isodyne method proposed by Pindera and his co-workers can deduce three stress components in the plane problem and can catch the stress information inside the loaded object nondestructively. The stress components are related with the derivative of the isodyne fringe order. In order to obtain the stress components correctly, accurately and efficiently the birefringence phase shift technique is applied into isodyne fringe pattern's distinction. In the paper a new method to obtain the phase shift by adding adjustable polarize and 1/4 wave length plate is presented, which is simple and no influence with different phase value.