I thought during a moment of curiosity that I'd ask the great Google oracle what side effects LED lighting may have,the results I found interesting, something to check out to pass a few minutes
Led and blue light
- Thread starter toad a caravan
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Erm, fluorescents lights also switch on and off at 100Hz(10ms) and are essentially mercury arc lights which emit in the blue/UV spectrum which the phosphor coating then converts a lot to visible light, the picture on old CRTs (TVs) was actually just a very fast spot of light travelling across the screen in 40ms ( interlaced at 25Hz per frame).On modern TVs LEDs also scan the LEDs ( take photograph with a 'fast camera) ( pulsing an LED increases the available light output without causing overheating of the semiconductor). The fact that blue light has a 'higher energy than red' is only true in the fact that an individual photon does have a higher energy ( 2.77 compared to 2.1 electron volts) , but the total energy received is due to the number of photons striking the retina - per second and a lot of apparently clear items tend to attenuate blue light more than the red end. Of course the newest source of flashing source of blue LEDs is the smartphone and given the hours people stare at them IMO poses a far bigger risk than LED lighting, if as we dont look at the ceiling lights, just what they illuminate, which often doesn't reflect blue (unless the upholstery is blue! ). The biggest source of 'blue' photons is that great thermonuclear object in the sky , which a lot of people seem to delight in exposing themselves to! IMO there are greater issues to worry about than led lighting.
- Nov 11, 2009
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When I was an apprentice at AEI I acquired a Mercury arc light for my bedroom. It seemed to take ages to come up to full output and it was ballasted by a filament. My brother used to put his arm around the door and turn the light off. It then had to cool down before it would switch on again. Not good if you are trying to complete your college coursework.
- Nov 16, 2015
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Or if your working a night shift in an Aircraft hanger, then you realise your batteries in your torch are U/S.
Just as there is a plethora of yellow glasses that are supposed to improve night driving vision, there are Blue Light Blocking glasses intended to protect the eye from the 'dangers' of Blue Light that various technology is emitting.
This comes from the fact that while we know UV light is harmful in excess Blue Light is still in the visible light part of the spectrum but approaching the band of UV.
While I've read a few studies about this there seems to little evidence to quantify any particular problem. Apparently 1 hour outside on a cloudy day is going to expose you to 30 times more Blue Light than 1 hour in front of a screen.
Blue light is not just restricted to LED technology but any source of illumination. But the thing is sources of artificial light vary in there colour temperature, which means they may have less output at the Blue End of the spectrum anyway.
From my photography experience my computer screens are calibrated to produce white light at about 6500k, which is bright sunlight and would contain light in the Blue end of the spectrum. The Led lights in my house are approximately 6000k because that's what I like. But many photographers and house owners prefer a warmer light of less than 4500k...less blue.
Much of the concern is due to how much screen time people now have. But studies have shown that eye problems are not necessarily due to blue light but the fact that we look at screens closely and surprisingly blink less, so not lubricating the eyes as much.
Then the move to LED car lighting also gets exploited as a possible harm when we only get short exposure to them. One interesting fact that came up about LED car lights is that as you get older it takes longer for the eyes to recover from a blast of oncoming light. Nine minutes was quoted compared to a few seconds for those younger drivers.
I've spent many many years in front of various screens for hours on end and although I wear glasses the prescription is small and has hardly changed in the last 15 years. I have no other problems using them for prolonged periods of time but then I calibrate them properly...both colour temperature and illuminance.
This comes from the fact that while we know UV light is harmful in excess Blue Light is still in the visible light part of the spectrum but approaching the band of UV.
While I've read a few studies about this there seems to little evidence to quantify any particular problem. Apparently 1 hour outside on a cloudy day is going to expose you to 30 times more Blue Light than 1 hour in front of a screen.
Blue light is not just restricted to LED technology but any source of illumination. But the thing is sources of artificial light vary in there colour temperature, which means they may have less output at the Blue End of the spectrum anyway.
From my photography experience my computer screens are calibrated to produce white light at about 6500k, which is bright sunlight and would contain light in the Blue end of the spectrum. The Led lights in my house are approximately 6000k because that's what I like. But many photographers and house owners prefer a warmer light of less than 4500k...less blue.
Much of the concern is due to how much screen time people now have. But studies have shown that eye problems are not necessarily due to blue light but the fact that we look at screens closely and surprisingly blink less, so not lubricating the eyes as much.
Then the move to LED car lighting also gets exploited as a possible harm when we only get short exposure to them. One interesting fact that came up about LED car lights is that as you get older it takes longer for the eyes to recover from a blast of oncoming light. Nine minutes was quoted compared to a few seconds for those younger drivers.
I've spent many many years in front of various screens for hours on end and although I wear glasses the prescription is small and has hardly changed in the last 15 years. I have no other problems using them for prolonged periods of time but then I calibrate them properly...both colour temperature and illuminance.
- Nov 11, 2009
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- 9,190
- 50,935
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