How does blue light stimulate the circadian clock?

Referring to following article, I would like to know on how blue light stimulate the circadian clock.

What wavelength frequency (blue light) would be the most effective to stimulate the circadian clock?

Does anyone have any suggestions?
Thanks in advance

"White LEDs may actually emit more blue light than traditional light sources, even though the blue light might not be perceived by the user. This blue light is unlikely to pose a physical hazard to the retina. But it may stimulate the circadian clock (your internal biological clock) more than traditional light sources, keeping you awake, disrupting sleep, or having other effects on your circadian rhythm."

https://www.health.harvard.edu/blog/will-blue-light-from-electronic-devices-increase-my-risk-of-macular-degeneration-and-blindness-2019040816365