A METHOD AND APPARATUS FOR CALIBRATING DISPLAY DEVICES AND AUTOMATICALLY COMPENSATING FOR LOSS IN THEIR EFFICIENCY OVER TIME

摘要

Organic LED displays are vulnerable to developing age dependent non-uniformities of emitted light across a display matrix; there is accordingly a need for rapidly and accurately correcting such non-uniformities in an initially calibrated display device. As the decay of emitted light follows an exponential law, change in light output can be predicted by accumulating (i.e. performing numeric integration) the driving current for each individual pixel during an elapsed time; then, based on such predicted change, the driving current can be adjusted for each pixel such to compensate the decay. Another possibility of correcting non-uniformities is also described, by arranging a photodetector, such as a camera, for measuring the light emitted gy different single pixels or groups of the same, whose size is made stepwise progressively bigger by adequate displacement of the photodetector along X, Y and Z axis, while correcting unevenesses at every step.