US Patent 9228936 Birefringence measurement of polycrystalline silicon samples or the like

A birefringence measurement system includes a lens mounted for selective movement into and out of use in the optical setup so that a wide range of sample types can be handled by the system without reconfiguring the primary components of the optical setup of the system (moving the detector, changing the light source power, etc.) in a manner that would sacrifice the cost effectiveness, efficiency, mechanical reliability and repeatability of measurements for such systems.