SoylentNews is people
SoylentNews
Interesting article at Business Insider on why we don't like LED bulbs:
There's a handy trick for reading station signs that otherwise fly past in a blur as you travel in a high-speed train. Look at one side of the window and then immediately at the other side of the window. When you change your gaze, your eyes will automatically make a rapid jerking movement, known as a saccade. If the direction of the saccade is the same as that of the train, your eyes will freeze the image for a split second, long enough to read the station name if you time things right.
Saccades are very fast movements of the eyes. Their exact speed depends on the size of the movement, but large saccades can move the eyes at the same rate as a high-speed train. The image of the station name becomes visible because it is travelling at the same speed as the eye, and the images before and after the saccade are blurred and so don't interfere with the image of the sign. This shows us that our vision is still working when our eyes move rapidly during saccades.
Scientists used to think we could see no more than about 90 flashes of light a second but now we know it's more like 2,000 because the eyes move so rapidly when we change gaze from one point to another. During the eye movement, the flicker of light creates a pattern that we can see. And this has some surprising consequences for our health thanks to the way some types of lighting can affect us. In particular, it could discourage people from using more energy-saving LED lightbulbs.
Most lighting is electric and powered by an alternating current supply, which makes the bulbs continually dim and then brighten again at a very fast rate. Unlike filament lamps and to a lesser extent fluorescent lamps, LEDs don't just dim but effectively turn on and off completely (unless the current is maintained in some way).
The answer is not to make them less piercing?
(Score: 3, Informative) by Unixnut on Saturday July 29 2017, @12:38PM
The solution I chose when I designed the LED lighting for my place, is to not rely on the LED bulbs to provide flicker free output. Rather I made use of a DC-DC converter at 20khz to step down mains voltage from 240V to 12V. It is was a standard COTS model used for halogen bulbs, but I made sure it had a high switching frequency (most do nowadays).
That, coupled with a capacitor in parallel, and my LED lighting system is completely flicker free. As the LEDs are designed for AC, but rectify it internally, you don't even have to worry about the polarity when you install them, and I can buy the cheapest 12V LEDs and still have nice flicker free output.
This is a solved problem. Indeed we had this problem back in the day with fluorescents, when in the 80s and 90s they used magnetic ballasts that worked at 50/60Hz, and you could see the flicker (and would cause problems for some people). Difference fluorescents were not straight on/off like the LEDs, so the flicker was smoother a bit by the phosphor and hot gas.
The solution back then was to decouple the ballast from the lights, and use high performance digital ballasts that worked at high frequency, eliminating the flicker problem. Now march of technology means every CFL can have one of these digital ballasts, but it is not the case with LEDs.