激光共焦干涉面形快速高精度自动测量

Laser confocal interference surface rapid and high-precision automatic measurement

针对传统球面面形干涉测量中手动调整被测件姿态精度低、速度慢的问题,提出了激光共焦干涉面形快速高精度自动测量方法。该方法通过共焦精密定焦技术实现了对被测件共焦位置的高精度轴向定位;通过五维自动调整架对被测件进行姿态调整,实现了被测件的高精度横向定位;通过Zernike拟合对被测件进行精调以减小离焦误差和倾斜误差,实现了对干涉面形的零条纹调整。最终实现了激光共焦干涉面形自动测量。构建了激光共焦干涉面形测量系统,实验表明:该方法的面形测量结果与Zygo干涉仪的测量结果相差0.000 6λ,重复测量精度可达0.001 9λ,平均单次干涉面形测量时间为16.5 s,与手动调整至零条纹相比测量效率提高了1.56倍。该方法为干涉面形的快速高精度测量提供了一种有效的手段。

Considering the low accuracy and slow speed of measuring objects with spherical surfaces using traditional interferometry due to manual adjustments,an automatic laser confocal interferometric method is proposed for rapid and high-precision measurement of surface shapes.This method utilizes precise confocal fixed-focus technology for accurate confocal axial positioning of the object.The object's posture is adjusted using a five-dimensional workbench.Zernike fitting is employed to minimize defocus and tilt errors,achiev⁃ing zero-order fringe adjustment and automatic determination of the surface shape.A laser confocal interfer⁃ometric measurement system was developed for this purpose.Experimental results show that the difference between the automatic interference measurement results and those of the Zygo interferometer is 0.0006λ,with a repeatability accuracy of 0.0019λ.The average measurement time for a single surface is 16.5 s,im⁃proving measurement efficiency by 1.56 times compared to manual adjustments.This method offers an effective solution for the rapid and precise measurement of interferometric surface shapes.