具有高空间分辨力的整形环形光式差动共焦测量法

提出一种新的具有高空间分辨力的整形环形光式差动共焦测量方法。该方法通过整形环形光式共焦测量法和锐化爱里斑主瓣，改善系统横向分辨力；通过差动共焦测量法改善系统的轴向分辨力，最终达到提高系统空间分辨能力的目的。理论分析和实验表明：整形环形光内孔归一化半径ε越大，横向分辨力改善越明显，量程扩展范围越宽；当入射光波长λ=632.8nm，物镜数值孔径取NA=0.85，ε=0.5时，该系统的横向分辨力优于0.2μm，轴向分辨力优于2nm。该方法为光触针测量系统空间分辨力的提高提供了1种新的方法，可广泛应用于超精密三维微细结构工件的超精密测量。

Shaped annular beam differential confocal measurement with higher spatial resolution

A novel shaped annular beam heterodyne confocal measurement system (SABHCMS) is proposed. The shaped annular beam confocal measurement method for sharpening the main lobe of Airy spot is used to improve the lateral resolution of a laser probe measurement system (LPMS),and the heterodyne confocal measurement method is used to improve the axial resolution of LPMS,thereby the spatial resolution of LPMS is improved. Experimental comparison and analyses indicate that both lateral resolution and measurement range of SABHCMS are improved as the normalized radius of the annular beam inner aperture ε increases;the lateral resolution of SABHCMS is better than 0.2 μm and the axial resolution of SABHCMS is better than 2 nm when the wavelength (λ)of the incident beam is 632.8 nm,the numerical aperture (NA) of the objective lens is 0.85 and the normalized inner radius (ε) of the annular beam is 0.5. It is therefore concluded that SABHCMS is a new approach to higher spatial resolution of LPMS and can be used for ultra-precise measurement of microstructural workpieces.