Patent ID: 6946650
Filing Date: 2005-09-20
Classification: A61G,G01D,G01L

Abstract:
1. A device for sensing relative position or orientation of first and second members comprising a source of light having first and second color components; a filter having first and second portions respectively preferentially passing said first and second color components, and substantially fixed relative to the first member; a mask, having first and second portions respectively relatively transparent to and opaque to both said first and second color components, and substantially fixed relative to the second member; and a sensor for detecting the first and second color components, wherein: the mask and the filter are mounted along one or more light paths between the source and sensor; and a change in said position or orientation causes a varying relative occlusion of said first and second filter portions by said second mask portions so as to vary a relative proportion of said first and second color components detected by the sensor.