Impact of VLC on Light Emission Quality of White LEDs

This paper reports the effect of data modulation on the emitted light quality of phosphor converted white LEDs. The results showed that provided the expected average current driving the LEDs remains unchanged then the emitted light quality will stay the same. For a dc-balanced modulating signal, with a nonvarying average value, any fluctuations in the instantaneous driving current due to data modulation do not have any significant impact on the measured light quality metrics. For visible light communication applications therefore, a dc-balanced signalling becomes a prerequisite if the expected quality of light emitted by the LEDs is to be preserved. The findings are premised on adequate thermal management for the LEDs under test.