用于在线检测的紧凑型多测量模式干涉仪

Compact multi-measurement mode interferometer for on-machine testing

光学干涉仪由于高精度、全口径、非接触特点在光学元件的检测中具有极其广泛的应用。针对光学元件加工在线检测需要,提出了一种紧凑型的多测量模式瞬态干涉仪。该系统可同时实现单波长激光干涉、多波长激光干涉以及LED干涉显微测量等多种工作模式,以分别满足不同动态范围宏观面形以及表面粗糙度等显微结构的干涉检测。针对在线检测应用中复杂的环境振动影响,系统采用偏振相机来实现瞬态的偏振移相波前检测。为验证系统方案的可行性,对测量系统的主要误差因素进行了分析,并对不同工作模式下的金刚石车削机床在线检测结果与Zygo激光干涉仪和Zygo光学轮廓仪进行了比对实验,同时也利用多波长技术对自由曲面进行了在线检测。结果表明该系统可实现高精度的多测量模式,并且还可以满足大动态范围波前测量要求。该系统结构紧凑,整体尺寸仅为195 mm×160 mm×65 mm,极其适合车削机床的在线安装及检测。同时系统基于瞬态波前检测,具有对环境扰动不敏感的特点,在机床对中工具在线调整以及加工元件等在线检测中具有广泛的应用前景。

With the advantages of high precision,full field and non-contact testing,the interferometers have been widely applied in the testing of optical elements.To meet the need of on-machine testing of optical elements in the machining stage,a compact interferometer with multiple working modes was proposed to achieve transient testing.The proposed system can work in modes including single-wavelength laser interferometer,multiwavelength interferometer and LED interferometric microscope,enabling the testing of surface figure with large dynamic range,surface roughness microscopic structures.A polarization camera was utilized to realize the simultaneous phase-shifting measurement with a single shot,by which the effect environmental disturbance can be minimized.To demonstrate the feasibility of the proposed interferometer,the on-machine testing in various working modes have been carried out on diamond turning machine,as well as the control experiment with Zygo laser interferometer and Zygo optical profiler;Besides,the freeform surface testing has also been achieved with the proposed interferometer.High measurement accuracy and large dynamic range has been achieved in experiments.It was compact in system with dimensions of 195 mm×160 mm×65 mm,making it extremely suitable for installing and testing on machining equipment.Besides,the transient wavefront testing makes the proposed system insensitive to environmental disturbance,and it has a great prospect for application in onmachine testing of alignment tool and various optical elements in machining stage.