There are two mechanisms of action how light affect humans discussed here:
- Amount of energy: shorter (blue) wavelengths are more energetic than lower (red), so it can be assumed that they damage photoreceptors more.
- Psychological: bluish light is associated with day by our biochemistry. Higher amounts of bluish light makes our brains more awake (e.g. suppressing production of melatonin)
Point 1 leaves conclusion that reducing amount of blue light from the monitor is always a good thing, while point 2 means that it's helpful as you plan to go to sleep. From my experience I can say that #2 is very true, as dim and warm light in the workplace made me sleepy and inefficient. Changing light sources to bright and cool fluorescent lights helped a lot. Also I've installed RGB led lighting in my living room and discovered that using only red light at the end of the day makes falling asleep easier. Just looking at BenQ's idea it certainly appeals to me.
However, the purpose of a monitor is to reproduce colors accurately. The question remains if the amount of blue can be reduced without affecting either color balance or just lowering brightness altogether. Modern "white" LEDs commonly used as source of light in LCD monitors are primarily blue light sources with some yellow phosphorus thrown in to balance out main emission. If BenQ used different kind of LEDs of CCFLs (less bluish) then this technology could not be turned on and off, much less adjusted. To truly limit the amount of certain component on the fly, RGB-LEDs would have to be used as backlight (they are not used here, and I'm not aware of any affordable monitor with RGB LEDs). What is presented on the video seems like simply changing color temperature to a warmer one - which is available in almost every color monitor. Even if it's not plain old color temperature, but something more sophisticated, e.g. clamp on blue channel in gamma ramp then same effect can still be achieved in software, in graphic card's gamma settings.
I disagree much with the video on the site you've linked. Even layman like me can easily point out errors:
- Saying that blue light is almost as bad as UV light just because it sits next to it on a spectrum is plain scaremongering. The biggest danger of UV comes from the fact that human eye can't see UV, so it won't close the iris to block it. The eye may "think" it's dark in very bright UV light and let it all in. Blue light, as part of visible spectrum, does not present this danger.
- The picture of blue-violet going "deep into your eye" is laughable. It shows other parts of spectrum stop at the lens while only blue reaches retina. It's plain lie, of course. Red and green do reach the retina just as well, otherwise we wouldn't be able to perceive them.
Bottom line: I think that the idea of reducing amount of blue light is good, but BenQ's execution is just a marketing gimmick or not much more in the best case.
If you really want to considerably reduce amount of blue light coming from your monitor, I recommend changing white backgrounds to yellow ones (if you work with lots of white backgrounds). This will drastically cut blue light reaching your eyes in a way not possible when still retaining impression of whiteness. Of course, eliminating large, bright areas by using dark themes (white-on-black text) will greatly cut ALL light.
If you seek to reduce strain on your eyes from monitor then I agree with statement that the biggest issue is not just the amount of light coming from the monitor. The biggest factor IMHO is the difference between monitor and it's background, that is the rest of the room. Therefore never use a computer/phone/tablet in total darkness - leave some nightlight + lower brightness to match. Also don't be afraid to crank up monitor up to 11 in a sunny day. Most monitors are set up to allow easy access to brightness and contrast adjustment - exactly for this very reason. They are meant to be used every time light in the room changes.