製品 | 2021/5/14
3. Basic Structure of the Systems & Measurement Examples
①Acquisition of state of polarization over light source ②Acquisition of state of polarization with sample
③Birefringence (phase shift & axis orientation) at each point by comparison of the states of polarization
Why using circular polarizer film:
If we used a linear polarizer, the regions of the sample having the same axis orientation as the film would not be correctly evaluated (no sensitivity).
Circular polarizer film allows to obtain the same sensitivity to birefringence independently from axis orientation.
PA System : Measurement Example (1)
PA System : Measurement Example (2)
PA Series include a model for microscopic applications, enabling evaluation of very small samples.
PA System : Measurement Example (3)
Plastic molded part (test piece) : evaluation of the differences between materials
Differences of material & molding parameters appear clearly as differences in the birefringence profile.
Range limitations of PA Series systems
The maximum birefringence that can be measured by PA system is λ/4.
Samples exhibiting greater retardation will be displayed with wrapped around values.
Evolution of recorded retardation for growing applied force on test piece (photo-elastic)
Values over ¼ of operating wavelength (520nm) are wrapped around.
It can result in ripples that do not exist in reality.
PA Series is limited to the evaluation of samples of less than 100nm of birefringence.