由自由曲面棱镜光学系统所组成的头戴显示器具有体积小、像质高和视场大等优点。利用矢量像差理论傍轴近似结果对具有倾斜曲面的光学系统进行初始结构设计,根据这种方法，以KOPIN公司生产的VGA芯片为例，对头戴显示器中自由曲面光学系统进行设计，将确定的初始结构参数输入光学设计软件Zemax进行优化设计。设计结果验证了确定初始结构方法的可行性，表明头戴显示器中自由曲面棱镜的设计方法可应用于具有倾斜曲面的光学系统设计。

The head mounted display (HMD) with a free-form-surface (FFS) prism owns merits of small volume, good image quality and wide FOV. The initialization structure of optical system with tilted surfaces was designed according to the parixial vector aberration theory. A FFS optical system for a practical HMD was designed by entering the initial structure paramiters to the Zemax software to optimize the designed results. The result verifies the feasibility of this method, and indicates that the method to design the FFS prism in HMD can be applied to the design of other optical system with titled suface.