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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: 2) by frojack on Saturday July 29 2017, @07:32PM (1 child)
Exactly.
Buy the ones that aren't billed as "daylight" or some such, and appear "warmer" and everybody forgets they are LEDs.
I've never heard a complaint about LEDs that wasn't about the light "color".
Seems pretty thin to go digging around for a use case (saccades, a term nobody ever knew prior to this article) and then suggesting we shouldn't use LEDs because: Trains
No, you are mistaken. I've always had this sig.
(Score: 2) by driverless on Sunday July 30 2017, @05:15AM
Some of us are geeky, or perhaps sad, enough to be familiar with them (google "confabulation across saccades" and "chronostasis" for some interesting reading). What isn't so obvious in this case is whether the authors merely stumbled across the term on wikipedia and decided to tie it to LED lighting, or whether it's more rigorous than that. The authors are psychologists rather than EE's or similar so it's likely they have more than just a passing familiarity with saccades, but still, the ability to discern the presence of flicker in some cases even at higher-than-expected frequencies doesn't necessarily tie to people disliking LEDs when told that they're seeing LED light (but not when they don't know it's LEDs). For example my LED lighting is pretty much full-spectrum daylight (measured with a spectrometer) with no measurable flicker (mostly due to good diffusers over the emitters), and that's off-the-shelf stuff from the local hardware store, not some exotic expensive lighting. OTOH my laptop... no visible flicker, but it's actually flickering like mad on the scale, and the spectrum is mostly discrete bands on a spectrometer.
So I think the only way to tell whether you're OK with it is to go to the store and see it in action. If you're one of those people who are allergic to LEDs, you'll need a blinded test/evaluation so you don't automatically detect the evil miasma emanating from what you're told is an LED light.
Incidentally, a quick way to measure flicker in any kind of lighting is to use a fidget spinner. Spin it at speed, if you get a kind of strobe effect you've got flicker, with smooth motion you haven't.