Patent ID: 9562793
Date: 2017-02-07
CPC Classifications: G01D

Claim:
1. An illumination portion for an optical encoder which comprises the illumination portion, a scale grating extending along a measuring axis direction and arranged to receive light from the illumination portion, and a detector configuration arranged to receive light from the scale grating, wherein: the illumination portion comprises an addressable light source array; at least one of the scale grating or the addressable light source array is configured to move relative to the other along the measuring axis direction; the addressable light source array comprises individual sources arranged along the measuring axis direction; the addressable light source array is configured to provide at least first and second addressable sets of the individual sources, the first addressable set including a first plurality of the individual sources arranged along the measuring axis direction, and the second addressable set including a second plurality of the individual sources arranged along the measuring axis direction; the individual sources of the first addressable set of the individual sources are arranged periodically along the measuring axis direction having a first pitch P the individual sources of the second addressable set of the individual sources are arranged periodically along the measuring axis direction having a second pitch P