为了解决离轴虚像系统中像散对清晰度的影响问题,提出了一种在全视场范围内消像散的反射面设计思路,并给出了基于微分方程的消像散反射面的设计算法。设计的消像散面型可以有效地校正系统各视场的像散,减小弥散斑尺寸。将消像散面型应用在视场为60°×40°的离轴虚像系统中,各视场弥散斑半径均小于艾里斑半径。将采用消像散反射面的设计结果与相同参数下采用球面和轮胎面时进行对比,可以发现,在采用消像散反射面的设计结果中,弥散斑均方根半径和像散绝对值小于全视场范围内采用球面时的20%,且小于边缘视场内采用轮胎面时的20%。

In order to solve the problem of astigmatism which affects the clarity in virtual system, a type of reflection surface design is put forward for astigmatism correction in the full field, and the design algorithm of the anastigmatic reflection surface based on differential equations is presented. The designed anastigmatic surface can correct astigmatism at each field of view effectively and decrease the size of dispersion spot. An astigmatic surface is applied in the off-axis virtual display system with the field of view of 60°×40°, and the radius of dispersion spot at each field of view is less than that of the Airy disk. The design results of the anastigmatic reflection surface are compared with the results designed by a spherical and a toroidal surface with the same parameters. It is found that the root mean square radius of dispersion spot and the absolute value of astigmatism designed by anastigmatic reflection surface are less than 20% of the result designed by a spherical reflective surface at the full field, and they are less than 20% of the result designed by a toroidal reflective surface at the margin field.