Patent ID: 7552873

Claim:
An optical encoder, comprising: a light source; a detector array positioned in spaced-apart relation to the light source, the detector array comprising at least one detector set, and each of the at least one detector set comprising a plurality of detector elements; and a code member positioned between the light source and the detector array, the code member and the detector array being moveable with respect to one another along a displacement direction, and the code member defining a plurality of openings through which light emitted by the light source is filtered to produce light spots that travel across the detector array as the code member moves with respect to the detector array, wherein the light source, the detector array and the code member are positioned, and the openings in the code member are sized, to cause the light spots to have dimensions along the displacement direction that are less than a width of one of the detector sets, but greater than a width of one of the detector elements.