Study On The Mechanism Of Innovative Micro/Nano Measuring Probes

Three kinds of innovative micro/nano measuring probe system will be introduced in this paper, which developed from the DVD pickup head combining with the analysis about the optical theory, the mechanism structure and the electronics characteristic of pickup head. It consists of the optical non-contact probe system, optical auto focusing probe system, optical touch trigger probe system. Focal error signal of pickup head is achieved according to the Astigmatical principle, and that the optical non-contact probe system with the measurement ranges of 2um and the measurement uncertainty of 1.1nm is obtained. This probe system is immune to the variation of reflective ratios and curvature on the surfaces of samples via improvement of the signal process method. For augment of the measurement range of probe system, the systemic model of the voice coil motor in pickup head is investigated, and then the auto focusing non-contact optical probe system with 600um measurement range is developed via the systemic recognition, the design and control of PID parameters and the hysteresis compensation of voice coil motor. At first, the measurement uncertainty of this probe system is 0.2um because of the influence of hysteresis and the method of signal process. The influence of hysteresis is resolved associating the developed miniature Michelson interferometer with voice coil motor. Consequently the measurement precision of the auto focusing probe system is improved with the range of about 1mm and the measurement uncertainty of better than 30nm. The optical touch trigger probe system is achieved with the basis of the high-precision characteristic of optical non-contact probe system and a high sensitive trigger structure. The 3D spatial force model and pre-travel model of the probe system is established that the trigger force is less than 40uN and the repeatability on same direction is about 11.2nm. These three kinds of probe system described above could be assembled on high-precision measurement instruments for different measurement demands.