Meaning
International documentation establishing a standardized procedure for measuring residual birefringence in optical glass ensures consistency in quality and material specification across global supply chains. Adherence to ISO 11455 allows manufacturers to quantify internal stresses that cause refractive index variations in glass materials. This standard covers measurements taken using polarimetric methods.
It applies to both raw glass blocks and finished transmissive components.
Testing Method
Quantitative evaluation of stress-induced double refraction uses a polarized light source and a compensator to measure the phase retardation of the transmitted light. Through the application of ISO 11455, test laboratories can output consistent retardance values in nanometers per centimeter. This testing run answers the readiness question for optical materials before they are released to high-precision lens production.
Quality Compliance
Sustaining high yield in the manufacture of complex multi-lens systems depends on the reliability of the glass substrates. When raw material is purchased, the supplier’s forecast of birefringence is often a nominal value, but compliance with ISO 11455 requires a demonstrated rate of testing on a representative sample of each melt. Failure to audit materials against this standard before machining can lead to optical aberration in the final production assemblies, resulting in expensive scrap.
Industrial Impact
Standardized birefringence metrics support the international trade of raw optical glass by establishing clear threshold criteria.
