目前国内用于激光标刻机的f-theta镜头的视场角一般小于60°。采用望远镜结构，利用视觉放大率增大视场角，得到了超广角90°镜头。该方法具有简洁、可靠、易实现等特点。通过初级像差分析，确定系统的初级结构参数，利用ZEMAX软件优化得到了大工作面为285 mm的f-theta镜头，镜头线性畸变误差值不超过1 %，在半径为698 μm的圆内，能量集中度为80%，聚焦性能接近衍射极限。

The field angle of f-theta lens used in laser marking system is generally less than 60°. By adopting a telescope structure and using a method of visual magnification, a super wide lens with the field angle of 90°was obtained in the optical system. The method is simple, reliable, and easy to achieve. Based on the analysis of primary aberrations, the parameters of initial structure were determined, and the f-theta lens with a large working area of 285 mm in diameter was obtained by optimizing the initial structure with ZEMAX. The linear distortion error of the lens is less than 1%, the energy concentration rate is 80% in the circle with a radius of 698 μm and the focusing performance is diffraction-limited.