Three-dimensional interferometric and fiber-optic displacement measuring probe

A novel three-dimensional interferometric and fiber-optic displacement measuring probe is described. As an important sensing part of a coordinate measuring machine, this compact measuring probe is successfully used in coordinate and surface scanning measurements of several types of complicated workpieces in precision engineering metrology. It is also applicable to three-dimensional vibration measurement. The distinguishing feature of this probe resides in its higher measurement accuracy on a relatively large measuring range, as compared with other conventional electric 3-D measuring probes commonly used in coordinate measuring machines. ±0.2 μm accuracy is achieved in a ±100 μm range in any spatial direction. The measuring force is less than 0.33N. This probe is very suitable for continuous surface scanning measurement. This three-dimensional interferometric and fiber-optic measuring probe consists mainly of three parts. The resilient mechanical part provides a universal movement for the measuring tip. The interferometric and fiber-optic small displacement sensing part measures this universal movement in the X, Y, and Z directions simultaneously and precisely. The opto-electronic signal detecting and processing part gives a real-time digital display of the measuring tip spatial displacement.