Patent ID: 8598509
Filing Date: 2013-12-03
Classification: B33Y,G01D

Abstract:
1. An optical encoder for use with a deposition head of a direct digital manufacturing system that is configured to toggle between a raised position and a lowered position along a first axis, the optical encoder comprising: a set of at least four light sources configured to emit light rays in a serial manner; an encoded scale comprising a reflective component and a non-reflective region offset along the first axis, the reflective component being configured to reflect at least a portion of the emitted light rays; a photodetector associated with the set of at least four light sources, wherein the photodetector is configured to detect at least a portion of the reflected light rays and to generate signals based on the detected light rays for each of the light sources, wherein the photodetector has a characteristic length along the first axis, and wherein the photodetector is offset from the encoded scale by a distance that is less than about 300% of the characteristic length; and a controller configured to determine positions of the encoded scale along the first axis based at least in part of the generated signals, wherein the determined positions of the encoded scale correspond to toggle positions of the deposition head along the first axis.