Development of an auto-focus 3D measurement system using piezoelectric actuator

In this study is developed by firstly modifying a DVD-ROM drive optical pickup head into height displacement sensor in order to measure the height displacement, and then using a commercially available industrial CCD to capture images immediately for planar contour measurement, and finally integrating an optical design with a 3D measurement system. The system can measure small workpiece surface conditions, such as pore size, angle, surface morphology, etc. An additional line nano-positioning stage was designed into this system to drive the 3D measurement system for measuring of the long-stroke automatic focus. Therefore, we have successfully designed a low-cost, high-precision autofocusing 3D measurement system with linear nano-positioning function. The overall system was independently developed from the nano-positioning stage design, the optical design, the sensing system, and the circuit design, etc. Consequently, the product has considerably commercial appeal and lends itself to a wide range of potential applications.