变焦距光学系统凸轮曲线设计是保证光学系统变焦精确、平滑和驱动力均衡的关键。以2运动组元变焦系统的牛顿法变焦推导公式为依据，分析等间隔设计和等角距设计凸轮曲线方法的特点，结合EBA20X10光学镜头设计实例，探讨了结合2者优点实现复合式凸轮曲线优化设计的方法。文中等间距是指变倍透镜组沿光轴的移动量与凸轮转角呈线性关系，凸轮曲线沿圆周展开为直线；等角距是指系统焦距与凸轮转角呈线性关系。最后介绍了可实现3种凸轮曲线辅助设计的软件工具OZSAD V1．2。设计结果表明，该设计方法可以降低凸轮曲线压力角，减少总展开角及加工点对数，还可保证凸轮的设计精度。

The design of the cam curves of the zoom system is critical to keep the precise,smooth and balance movement of the optical system. The article analyzes the characteristics of equal space design (ESD) and equal angle step design (EASD),the former means the motion of zoom group is linear to turning angle of cam and the cam curves are expanded as a beeline,the latter. means the focus is linear to turning angle of cam. A solution to overcome the shortcomings of these design methods is proposed,which combines the merits on their adaptable zoom segments. At last,a kind of cam assistant design software OZSAD (optical zoom system assistant design software) Vl. 2 is introduced,which can conveniently and quickly meet all three kinds of design requirements. It is proved that the pressure angle of cam curve,the total expanded angle and the points of cam curve could be effectively reduced. Therefore,the design precision could be reached.