Optical Design Of The F-θ Lens In Laser Scanning System

f-θ lens is one of the most important parts of laser scanning system, and has been widely used in many equipments, such as laser marking machine, faxes, laser printer, laser pattern generator for semiconductor integrated circuit, laser scanning in the precision meter equipment and so on.In this dissertation, it will design a f-θ lens of laser scanning in non-contact. The character of this lens is that, having negative distortion, belonging to far center ray in image space, imaging with homogeneous light, the request of image quality for wavefront less than λ/4, be alined with image quality in whole image surface, the image surface is plane with no vignetting.Based on the theory of primary aberration, the first-order optical parameters are determined at first through its paraxial analysis, flat-field condition, and aberration characteristics. The initial structure parameters of the f-θ lens are obtained with P-W method. And then a few of optimal f-θ lens with required optical performances are gained with ZEMAX optical design software under reasonable merit function. The performance evaluation and tolerance analyse of f-θ lens are given in detail. The designed lenses are simple、compact,its focus is short and their cost are low with high precision. The focusing performances are within diffraction limit, the relative illuminations quite uniform and the distortion relative to the f-6linear relation small.