Led and blue light

[toad a caravan]

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

 

[IanB1485]

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.

 

[otherclive]

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.