F Theta Scanning Laser Lens is used in fiber laser marking machine having size 110x110mm,150x150mm,175x175mm, 200x200mm,250x250mm and 300x300mm. F-theta lenses are designed to focus a laser beam onto a plane image plane. They are often used in a scanning system with two galvanometer mirrors. One mirror is responsible for beam deflection in one direction and the second one for the perpendicular direction