Development and characterization of a high speed linear-moving-stage for multispectral measurements

Multispectral imaging is one of the key topics in the upcoming years, a lot of measurement tasks can be solved using the additional spectral information. For the separation of these additional information bands plenty technologies were developed in the last decades. All of them have characteristic advantages and disadvantages. One working principle is the use of a filter wheel containing different filters between the image sensor and the lens. The additional element inside the light propagation path as well as the lens imperfections lead to chromatic aberrations. To compensate the resulting focus error some investigation were made. One option is the movement of the image sensor stage to a better focus position. Therefore high precision moving stage with high movement speed are characteristic parameters which have to be considered during the construction. In this paper a linear motor stage paired with two high precision linear bearings were connected together to achieve the demanded requirements. For the evaluation of this new approach, several measurements determining the dynamic as well as the static specifications were made to proof the achieved characteristics and will be shown in the paper. With this approach, a miniaturised precision system inside the multispectral imager a precision repeatability of less than four microns can be achieved.