App note from OSRAM about LED rework on signages and their demand for more sophosticated tools. Link here (PDF)
SMT LEDs have became more and more popular in video wall and signage applications, replacing radial LEDs. This leads to more difficulties during the repair or replacement of failed LEDs on PCBs, especially for QFN (Quad Flat No-lead) packages, as there is no exposed lead. This application note provides basic information on how to rework the SMT LEDs in video wall and signage applications. To describe the rework process the DISPLIX Oval LED was chosen an example, as the rework of this LED is more challenging due to the lack of exposed lead and the oval lens on top. However, the procedure is also suitable for other LEDs. In this application note details on the materials used, examples of suitable equipment and the process are presented and described. Finally, the test results of the LED after the rework process are presented, showing that in this case the rework procedure did not cause any damage to the LED itself.