LED illumination - timing and strobing
Because LEDs have a long but finite life span, their useful operating life can be extended by ensuring that they are only powered on when necessary, particularly as LEDs can be switched on and off with virtually no delay in reaching full intensity. As an example, if an inspection requires an exposure time of 10ms, and lighting is only required every 100ms, the lighting system only needs to be lit to coincide with the exposure, extending its usable life by approximately factor 10. This diagram shows how the life of an LED could be doubled.