基于点源阵列的自由曲面非零位干涉检测系统设计方法

Design of Non-Null Interferometer Based on Point Source Array for Testing Freeform Surface

自由曲面光学元件因具有良好的消像差能力,又能简化系统的结构,已成为新一代理想光学元件。但由于面形的"自由"以及表面的大梯度变化,使得面形高精度检测缺乏有效方法,是该类元件制造和应用的瓶颈。提出了利用点源阵列给测试波前预载倾斜量来补偿被检自由曲面表面梯度的非零位干涉自由曲面面形测量方法。针对自由曲面非旋转对称的特点,提出了基于"黑匣子"思想的逆向光路设计方法,设计出了适合自由曲面面形测量的非零位干涉光路。根据设计方案,加工并制作了该干涉装置,对自由曲面眼镜片进行了实际的干涉图采样,验证了系统的可行性。

Freeform optical surface is a new generation of ideal optical element because it can effectively correct image aberrations and greatly simplify optical system structures. Because of its high gradients and strong deviations from ideal sphere, it is extremely difficult to measure freeform optical surface with sufficient accuracy, which is the key limitation on its fabrication and application. Therefore, a novel non-null interferential method based on the use of multiple test beams for illuminating freeform surface with different angels is presented, which can compensate local gradients of freeform optical surface. A reverse optical design method based on “black box” theory is proposed, which can resolve the problems caused by non-rotational asymmetry surface. A real non-null interferometer for testing freeform surface is designed, and an eyeglass with non-rotational asymmetry surface is measured successfully, which verifies the feasibility of the system.