Our Quality Requirements Standards
We have an impurity comparison card that compares the area of stains of different shapes

(1) One “large stain” and 2 “small stains” are allowed in one square meter, and the distance between each stain is at least 150mm
(2) 4 “small stains” are allowed in one square meter, and the distance between each stain is at least 150mm
(3) The distance between “large stain” and “large stain” is at least 300mm

(bubbles are the same as stains)
Large stain: 1-3 mm2, small stain: 0.3-1 mm2
Large air bubbles: 0.5-2 mm2, small air bubbles: 0.3-0.5 mm2