Datasheet

LUXEON LED Assembly and Handling Application Brief AB32 20121217 33
5.7 Reflow Accuracy
Global fiducials on the PCB board (see Figure 41) can help calculate the reflow accuracy between the centers of the component to the nominal
board position. Section 1.2 Optical Center explains how to find the theoretical optical center of the LUXEON LED. Philips Lumileds has
determined the placement accuracy after reflow to be well within 90µm in the x and y directions for the footprint of Figure 11. The placement
accuracy is determined as follows: The PCB onto which the LUXEON LED is assembled must have fiducials to determine the origin. The position of
the LUXEON LED is determined using the component fiducials. The difference between this measured value and the nominal placement position is
the placement accuracy.
Board fiducial
Board fiducial
Component
fiducials
Figure 41. The board fiducials provide the origin of the board. The fiducials on a LUXEON LED determine the optical center of the LED.
The difference between the measured coordinates of the optical center and the nominal position is the placement accuracy.