US Patent 7810901 Driving apparatus

A driving apparatus, including a driving device which moves an object along a predetermined path; a linear encoder including a linear scale and a detector one of which is moved relatively to the other when the object is moved along the predetermined path; a control device which controls, based on an output of the detector, the driving device to move the object along the predetermined path; and at least one stopper which engages, when the object is moved along the predetermined path, the object and thereby stops a further movement of the object. The linear scale includes at least one first scale portion having a plurality of first detectable portions provided at a predetermined pitch, and at least one second scale portion having a plurality of second detectable portions including at least one pair of adjacent second detectable portions which are adjacent to each other and which are distant from each other by a predetermined distance smaller than the predetermined pitch. The first scale portion and the second scale portion are located relative to each other such that when the object is moved toward the stopper, the detector first detects the first detectable portions and then detects the second detectable portions, while sequentially outputting a plurality of detection signals, and the control device controls, based on the detection signals, the driving device to move the object along the predetermined path.