Measurement of haze was generally done using an integrating sphere light transmittance measuring instrument based on the “Plastic optical characteristics test method (JIS K7105)”, but this method was changed to the “Haze measuring method for plastic/transparent material (ISO 1478)” (Figure b) and the “Total light transmittance test method for plastic/transparent material, Part-1 Single beam/compensation method (ISO 1478)”. The following formula is now used for haze measurement.