基于共光路干涉原理的精细表面粗糙度测量方法

A Method of Measuring Roughness of Fine Surfaces Using Interferometry Principle of Co-Optical Paths

提出了一种利用光的干涉原理测量光滑物体表面粗糙度的方法。该方法采用两光束共光路、同心聚焦扫描可实现表面粗糙度的绝对测量。使用一个半波片改变一路光束的偏振态,避免了传统测量系统中光路具有可逆性的问题,保证了系统的稳定性。使用一个1/4波片使接收端的光束偏振态方向一致,使干涉信号可见度最大。该系统光路结构简单,容易实现。对一标准量块进行了测量,并对光功率计分辨率对测量结果的影响进行了分析,结果表明本系统在实验室现有条件下可以测量轮廓算术平均偏差R_a为0．012μm的粗糙度量块。

A novel method using interferometric principle to measure the smooth surface roughness is proposed. The absolute measurement values of the surface roughness are achieved using two concentrical beams scanning the surface. The polarization state of the beam in one path is changed utilizing a half wave-plate, avoiding the reversibility problem of the previous similarly system widely-used, the stability of the system is ensured. A quarter-wave plate is used to make the consistency of the polarization states of the received light, making the utmost visibility of the interferometric signal. The set-up is simply and easy to be realized. The feasibility is verified by the measurement of a sample block. The effect of the resolution of the optical power detector is analyzed. The arithmetic average deviation value of the profile of a gage block of 0. 012 μm is obtained.