物体表面形貌的正弦相位调制实时干涉测量技术研究

表面形貌干涉测量技术是一种高精度的非接触式测量技术,在工业生产和科学研究中具有广泛的应用。提出一种实时测量表面形貌的正弦相位调制干涉测量新技术。该技术用激光二极管作光源,用自制的高速图像传感器探测干涉信号,通过信号处理电路实时解相得到被测表面所对应的相位分布,实时分析相位获得物体表面形貌。该技术消除了光强和部分外界干扰的影响,提高了系统的测量精度。楔形光学平板表面形貌的测量结果表明,测量点为60×60个的情况下,测量时间小于8.2 ms,重复测量精度(RMS)为4.3 nm。

A sinusoidal phase-modulating (SPM) interferometer for real-time surface profile measurement is proposed and analyzed. A laser diode and a high-speed image sensor are used as the light source and the photo detector. The phase corresponding to each measurement point on the surface is calculated by a signal processing circuit. The surface profile is obtained by the phase distribution . The interferometer is insensitive to vibrations of the optical components and fluctuations in the light source. The surface profile of an optical wedge was measured . For 60×60 measurement points, the measurement time was less than 8.2 ms. Repeatability in the measurements was 4.3 nm.