激光位移传感器的测量是基于目标表面的散射效应，表面的粗糙度特性直接影响散射测量光斑的光强。为研究粗糙表面对成像光斑光强的影响，通过构建粗糙表面的散射几何模型，利用基尔霍夫标量散射的解析理论，结合遮蔽函数统计模型，获得被测表面的粗糙特性与成像光斑光强的函数关系。根据传感器中位置敏感探测器(PSD)的检测原理，感光面上成像光斑光强大小将直接影响传感器的测量精度。实验分析了基于PSD的位移传感器对标准粗糙度样块的测量数据，结果表明不同的表面粗糙度将产生不同的测量误差，表面粗糙度Rq值越大散射光斑光强越大，但伴随遮蔽系数的显著增强，光斑光强将逐渐被削弱，而测量误差大小与光强的变化趋势相同，其中对Rq=0.8 μm左右的粗糙表面的测量误差最小。

The measurement of laser displacement sensor is based on the scattering effect of the surface, and the roughness characteristics of the target surface directly affects the light intensity of the scattering measurement spot. For the purpose of studying the impact of the roughened surface on the light intensity of the imaging spot, the scattering geometry model of rough surface is built. By using Kirchhoff scalar scattering analytical theory and combining shadowing function statistical model, the functional relationship between the characteristic of the rough surface and the scattering luminous flux is calculated. According to the detection principle of the position sensitive detector (PSD) in the sensor, the light intensity value of imaging spot on the photosensitive surface will directly affect the measurement accuracy of the sensor. Through the analysis of the measurement data of different standard roughness surfaces which are got from the displacement sensor based on PSD, the experimental results show that different surface roughnesses will produce different measurement errors, and when the Rq value of surface roughness is larger, the light intensity of scattering spot becomes larger. But accompanied by significant enhancement of the shadowing coefficient, the light intensity is gradually weakened, and the magnitude of measuring error has the same trend of changes with that of light intensity. For the roughened surface with Rq=0.8 μm the measurement error is the minimum.