Design of hybrid refractive-diffractive f-θ lens with multi-wavelength,large working area

The working area of f-θ lens is generally not larger than 350 mm×350 mm when used in laser scanning system. f-θ lenses with larger working areas overseas are of complicated structures. In order to obtain the f-θ lens with large working areas and relative simple structure to satisfy the scanning system's request, the special dispersion character of the binary optical element was applied, hybrid refractive-diffractive f-θ lenses working on the wavelength from 808 nm to 1064 nm was designed with the scanning ranges 450 mm×450 mm. The optical system was composed of only four spherical lenses with two kinds of common optical glasses. The tube length was less than 120mm. The system's structure was compact, its focusing performance was diffraction-limited working at the single wavelength, its distortion was small relative to the f-θ linear relation. The system meets the requirements of laser scanning systems with different waves on a large area.