LED brightness and uniformity inspection
The LED board is powered in a darkened cell and imaged from above at fixed exposure. The brightness of every LED is measured against the reference level; the distribution of the values and the weakest-to-brightest ratio are evaluated per board.
Each board shows its brightness distribution, average and weakest-LED value; the faulty LED is marked on the board and the tower signals the board OK/NG decision.
- 01 Position
- 02 Power-up
- 03 Measure LEDs
- 04 Decide
The camera head travels on the arm carriage to the next board.
- Mean brightness
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- Uniformity
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- Weakest LED
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Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
Ambient light, LED glare and changing exposure can hide the difference between weak and normal LEDs; a board average can mask a single low-brightness point.
Solution approach
The board is powered through contact points inside a darkened cell; the top camera images both boards in turn with the same view and exposure. LED regions are measured column by column; the intensity image and histogram show the individual lower limit and board uniformity separately.
Process steps
- 01
Position
The camera head travels on the arm carriage to the next board.
- 02
Power-up
The board is powered, the cell goes dark and the camera captures at fixed exposure.
- 03
Measure LEDs
Each LED is measured column by column and the distribution builds up in the histogram.
- 04
Decide
The single-LED lower limit and the board uniformity are evaluated together.
Related applications
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