Patent ID: 8431093

Claim:
A device comprising: a support comprising a first face; a plurality of light elements mounted in the support to form a two-dimensional array in the plane of the first face; a first centering structure mounted to extend from the first face of the support and comprising at least a first pair and a second pair of stop walls, wherein a pair of stop walls forms a corner; and a second centering structure mounted to extend from the first face of the support and comprising at least a third pair and a fourth pair of stop walls; wherein the first pair of stop walls and the third pair of stop walls form corners of a first positioning zone of a first type of plate and the second pair of stop walls and the fourth pair of stop walls form corners of a second positioning zone of a second type of plate; and further wherein the first centering structure and the second centering structure are positioned outside both the first positioning zone and the second positioning zone.