Method and device for path length measurement

摘要

The invention relates to a method and a device for path length measurement, having high resolution for the near zone, in particular for the position measurement of actuators. The invention occupies the field of contactless position measurement. The object of the invention is to provide a contactless method which makes absolute measurements and is largely independent of environmental influences and which permits very small paths and changes in position (up to 10 cm) to be measured within very short measuring times (up to 10,000 Hz) in conjunction with a resolution of better than one part per thousand of the measuring range. This object is achieved in the case of the method according to the invention by providing that a pattern of marks applied to the measuring section is projected by an optical system onto a receiving plane, and the image produced there is used for the purpose of position measurement.