基于虚拟双差动共焦的快速表面轮廓测量方法

Aiming at the problem that the scanning speed and scanning accuracy cannot be taken into account in the fixed focus process of traditional confocal microscopy, a fast surface profile measurement method based on virtual double differential confocal is proposed. This method shifts the traditional confocal response curve forward and backward by a specified amount to obtain virtual front focus and virtual back focus signals. Then the virtual front and back focus signals are subtracted from the original confocal signal respectively, and the subtraction results are added together to obtain a virtual double differential curve. The virtual double differential curve has the characteristics of large linear range and high fixed focus sensitivity. When the surface profile is acquired under the condition of large scanning distance, the rapid and high-precision fixed focus of the sample surface profile can be achieved. Simulation analysis and experimental results show that, compared with traditional differential confocal microscopy imaging methods, the virtual double-differential confocal surface profile measurement method can increase the imaging speed of geometric topography by more than 2 times while maintaining high precision and fixed focus.