Polariscope is an optical instrument designed to observe stress presence and stress distribution state inside transparent materials .

Objects of Polariscope
float glass plate, automotive glass
crystal , quartz , lens glass
glass container , glass vial , water glass
glass wafer , glass tube , laboratory glassware
resin plate , resin film , mold injection resin products
industrial new material glass , optical new material glass

Measuring principle
The internal stress of glass and plastic products has a birefringent characteristic. In other words, if there is stress inside of these types of products, light from the polarized lamp will be divided into different units, which produces optical interference phenomenon (ripple patterns) in turn.

From the observation of colored patterns, you can see stress distribution directly, then evaluate and improve the annealing process.

The inspection of plastic molds is more complex as the colored patterns caused by stress is irregular. A similar situation may occur with glass products, which is called stress stretching. For example, a qualified mold will have a large amount of stress released by tension.