Does LED lighting count as a dodgy technology?

[scatterandfocus]

I'm sure that some of the tech involved people at the eevblog forum know that LED lighting bothers some people's eyes.  And there have been studies showing that LED lighting can actually irreversibly damage the eyes.  So do you think that LED lighting should be included in the category of dodgy technology?  Maybe this will come off as a provocative topic, since LED lighting has more and more become the norm and we're all using it to some degree.

I have been looking at a screen most of the day searching for lighting solutions for a bench.  My eyes are toast. 

[james_s]

LED lighting dodgy? It's the entire future of lighting and has already displaced nearly everything else. Good quality LED lighting is available that can rival any other artificial light source out there and even a lot of the low cost stuff has gotten quite good. It is efficient and long lasting too, I fully retrofitted my house to LED back in 2011-2013 and the only failures I've had in that whole time were a couple of bulbs I used in fully enclosed fixtures despite the fact they warned not to. There's nothing dodgy about LED, it's mainstream, in 2019 outside of certain specialized applications there's no reason to consider anything else.

[Halcyon]

And there have been studies showing that LED lighting can actually irreversibly damage the eyes.

Don't look directly into bright or UV light sources, LED or otherwise as they can damage the eyes.

[Kjelt]

Nothing dodgy about the tech in it self.
Perhaps some companies make dodgy lighting with small spectrum solutions or bad diffusors or low quality electronics, but that is not the tech it self it is the implementation.
The only thing bad about LED lighting are the white outdoor luminaires that proven disturb wildlife.
You can also say why wildlife should live in the vicinity of outdoor luminaires.

[SeanB]

Not a dodgy tech, just dodgy implementation to cut cost as much as possible, and sadly the big names are also doing this to compete, making them with a similar lifetime to the incandescent lamp they are replacing. You should be able to have the LED fixtures have a lifetime in the order of decades, like the discharge lamps are capable of, with almost no loss in efficiency, but the desire to cut a cent of the price of all parts means that the actual LED units themselves are run at high current, hight heat, and thus at a lower efficiency, and with a much shorter operational life, while you can easily derate properly and use the same parts to get light output equivalent, but with a lifetime in decades. Just will cost double the price, and will use marginally less power as well, so long term you will have a lower TCO, but the only thing seen is the initial price, not the long term cost of short life, frequent replacement and higher power use.

[coppice]

I have been looking at a screen most of the day searching for lighting solutions for a bench.  My eyes are toast.

Have your eyes really been affected, or are you just tired after a long day?

[scatterandfocus]

I have been looking at a screen most of the day searching for lighting solutions for a bench.  My eyes are toast.

Have your eyes really been affected, or are you just tired after a long day?

Since the advent of LED backlit computer displays, my eyes have been affected, and it seems permanent.  I am easily prone to eye fatigue and strain, since.  It seems to have gotten worse since LED lighting became the norm.  I still use halogen bulbs at home in areas where light quality matters most, but I don't have any say elsewhere.  I also have some 90+ CRI Cree bulbs at home (daylight and soft white) that are used in less critical areas, but when I try to use them in areas where I do lots of reading, they do bother my eyes over time.  I have tried the high CRI GE bulbs too.  'High CRI' is a bit deceptive though, as CRI rating is a very small sample set of the full spectrum.  LED lighting (even the highest quality) still has high peaks at a few bands.  Also, only looking at CRI neverminds the effects of power switching schemes.  I should probably try some Yuji bulbs, but it is hard to swallow those prices when the situation might turn out to be very much the same as the Cree and GE bulbs.  And when looking at videos demonstrating Yuji lighting, I haven't noticed a great difference from the Cree and GE bulbs sold at local stores at much lower prices.

Obviously not everyone is affected in the same way as I am.  But I am far from alone too, as evidenced by so many blue-light blocking technologies available today, as well as manufacturers responding to blue-light and PWM complaints.  And the rising demand for high CRI LED lighting says something about the situation.

[Gyro]

I have been looking at a screen most of the day searching for lighting solutions for a bench.  My eyes are toast.

I'm not quite sure what you're asking. If it's looking at the LED backlit screen all day that has strained your eyes then that's an old problem, it was the same (or much worse) with CRT monitors. That's why employers are required to allow you time away from the screen to look at more distant objects. What you do at home is down to you of course. EDIT: I certainly developed eye problems in CRT days.

If you're talking about LED lighting in general, then LEDs are efficient light sources and all light sources need to be applied properly for comfort. Don't stare at the filaments of  incandescent lamps, there is far more IR energy, worst case you could burn your retinas or long term, develop 'glassblowers' cataracts from strong IR sources, or UV from unfiltered Halogen lamps come to that.

LEDs (apart from powerful IR ones or UV ones) are pretty benign and certainly not 'dodgy'.

[scatterandfocus]

I have been looking at a screen most of the day searching for lighting solutions for a bench.  My eyes are toast.

I'm not quite sure what you're asking. If it's looking at the LED backlit screen all day that has strained your eyes then that's an old problem, it was the same (or much worse) with CRT monitors. That's why employers are required to allow you time away from the screen to look at more distant objects. What you do at home is down to you of course. EDIT: I certainly developed eye problems in CRT days.

If you're talking about LED lighting in general, then LEDs are efficient light sources and all light sources need to be applied properly for comfort. Don't stare at the filaments of  incandescent lamps, there is far more IR energy, worst case you could burn your retinas or long term, develop 'glassblowers' cataracts from strong IR sources, or UV from unfiltered Halogen lamps come to that.

LEDs (apart from powerful IR ones or UV ones) are pretty benign and certainly not 'dodgy'.

I have been using computer displays across the various display technology periods, as many others my age and older have.  CRT, CFL, and LED.  This isn't something that just happened yesterday. 

[dferyance]

I had a few co-workers who insisted the florescent lighting gave them headaches. They convinced HR to essentially have the lights off in the office -- which applied to everyone. This wasn't that long ago so they were modern electronic ballasts where your eyes cannot pickup any flicker. Funny thing is, I get frequent headaches too but I don't jump at blaming the type of light bulb. If anything, I feel that sitting in a dark room looking at a bright monitor is uncomfortable. Humans are very prone to confirmation bias so we end up with essentially superstitious beliefs. So LED lights are bad and florescent lights are bad... maybe some people will think incandescent lights and candle lights are bad too.

What I don't like with LED is that many fixtures now come with the LEDs as non-replaceable. I guess people find it convenient but both the LEDs and the electronics have a lifespan and can fail. I much prefer LED bulbs with the Edison screw that can be replaced.

[Gyro]

I have been using computer displays across the various display technology periods, as many others my age and older have.  CRT, CFL, and LED.  This isn't something that just happened yesterday. 

So your

I have been looking at a screen most of the day searching for lighting solutions for a bench.  My eyes are toast.

comment is irrelevant to the discussion then? I'm sure you can understand how your OP could be confusing.

[scatterandfocus]

Here is an old article on the issues of LED lighting:  https://www.ledsmagazine.com/smart-lighting-iot/smart-cities/article/16699866/light-and-human-health-led-risks-highlighted

Here is a forum based around the discussion of the negative effects of LED lighting:  https://ledstrain.org/  Keep in mind that it isn't a science oriented forum.  It's mostly a bunch of users of LED displays who have been affected by it and who are trying to find solutions.

Here is an interview of a researcher on the effects of LED displays on retinal cells:  https://www.news-medical.net/news/20170330/Could-light-from-LED-screens-cause-irreversible-eye-damage.aspx  Obviously she is trying to pimp a specific blue-light blocking product, such is the world today.

Here is a news bit mentioning a study on the effects of LED lighting on the eyes: 

Obviously, take all of this as a kick off point for further inquiry, not as definitive sources for information on the topic.

[scatterandfocus]

I had a few co-workers who insisted the florescent lighting gave them headaches. They convinced HR to essentially have the lights off in the office -- which applied to everyone. This wasn't that long ago so they were modern electronic ballasts where your eyes cannot pickup any flicker. Funny thing is, I get frequent headaches too but I don't jump at blaming the type of light bulb. If anything, I feel that sitting in a dark room looking at a bright monitor is uncomfortable. Humans are very prone to confirmation bias so we end up with essentially superstitious beliefs. So LED lights are bad and florescent lights are bad... maybe some people will think incandescent lights and candle lights are bad too.

What I don't like with LED is that many fixtures now come with the LEDs as non-replaceable. I guess people find it convenient but both the LEDs and the electronics have a lifespan and can fail. I much prefer LED bulbs with the Edison screw that can be replaced.

At work most of the lights are fluorescent.  And they do bother my eyes when reading under them.  About 5 minutes at a time is all I can handle before my eyes hurt.  A major part of that is that the lights are all overhead, directly over work areas.  When I move off to the side, just out from under a light fixture, my eyes aren't bothered as much.  But I didn't have this issue until after using LED displays for some years.  I have been working under fluorescent lights since I was a kid in school and all of my adult wokrng life, as well as using CFL displays for some years.  It seems to me that since using LED displays over more recent years my eyes have become more sensitive to artificial light intensity, where I much prefer dimmer reading lighting.  It is supposed to be the other way around, where we need more light intensity for the same tasks as we age.  And when I read outdoors in the shade, I am not affected at all (same as ever), which is where I do most of my reading and computing on a laptop, as weather allows.

[Gyro]

I picked up an old Meiji direct view spectroscope of ebay a while back. The first thing I did (obviously) was to point it at various light sources.

I first tried the fluorescent tube lights in the garage and kitchen and was unsurprised to find a collection of very narrow spectral lines, the same with various compact fluorescent ones.

I tried the same thing with various white LEDs (bulbs and individual). I was expecting to see a strong blue component from the die and some compensating warming lines from the phosphor coating. In fact I found that the spectrum looked very smooth, with no obvious gaps or spikes. I found that really surprising.

Daylight was pretty similar (obviously not able to accurately judge the colour temperature difference) with the exception of the fine black Fraunhofer lines.


P.S. Filament lamps were boringly predictable, with a rolling off in the blue.

[scatterandfocus]

I have been using computer displays across the various display technology periods, as many others my age and older have.  CRT, CFL, and LED.  This isn't something that just happened yesterday. 

So your

I have been looking at a screen most of the day searching for lighting solutions for a bench.  My eyes are toast.

comment is irrelevant to the discussion then? I'm sure you can understand how your OP could be confusing.

Just to be clear, I never once got eye fatigue from CRT or CFL displays.  But I sure did get red and dry eyes from CRT's back in the day.  I first got eye strain from an LED display (my first LED display, on a laptop), and I have been prone to eye fatigue ever since.  I cut myself off well before eye strain can set in.  And I have noticed that with some LED displays I can't read from them for more than a few minutes before my eyes begin to be bothered.

[scatterandfocus]

I picked up an old Meiji direct view spectroscope of ebay a while back. The first thing I did (obviously) was to point it at various light sources.

I first tried the fluorescent tube lights in the garage and kitchen and was unsurprised to find a collection of very narrow spectral lines, the same with various compact fluorescent ones.

I tried the same thing with various white LEDs (bulbs and individual). I was expecting to see a strong blue component from the die and some compensating warming lines from the phosphor coating. In fact I found that the spectrum looked very smooth, with no obvious gaps or spikes. I found that really surprising.

Daylight was pretty similar (obviously not able to accurately judge the colour temperature difference) with the exception of the fine black Fraunhofer lines.


P.S. Filament lamps were boringly predictable, with a rolling off in the blue.

Now I want a spectrometer for my test gear kit.   Thanks?   

[coppice]

I first tried the fluorescent tube lights in the garage and kitchen and was unsurprised to find a collection of very narrow spectral lines, the same with various compact fluorescent ones.

A fluorescent lamp should give you a broad spectrum from the phophor and narrow lines from the mercury discharge. They use a glass which damps the UV lines from the mercury, but they still come through pretty strong when measured on a spectrometer. There have always been questions about the long term safety of those soft UV lines.

[scatterandfocus]

I picked up an old Meiji direct view spectroscope of ebay a while back. The first thing I did (obviously) was to point it at various light sources.

I first tried the fluorescent tube lights in the garage and kitchen and was unsurprised to find a collection of very narrow spectral lines, the same with various compact fluorescent ones.

I tried the same thing with various white LEDs (bulbs and individual). I was expecting to see a strong blue component from the die and some compensating warming lines from the phosphor coating. In fact I found that the spectrum looked very smooth, with no obvious gaps or spikes. I found that really surprising.

Daylight was pretty similar (obviously not able to accurately judge the colour temperature difference) with the exception of the fine black Fraunhofer lines.


P.S. Filament lamps were boringly predictable, with a rolling off in the blue.

Now I want a spectrometer for my test gear kit.   Thanks? 

Looking at spectrometers, now I ran into Theremino and Physicsopenlab.  That stuff looks fascinating and could too easily take over all of a person's free time.

[Gyro]

I first tried the fluorescent tube lights in the garage and kitchen and was unsurprised to find a collection of very narrow spectral lines, the same with various compact fluorescent ones.

A fluorescent lamp should give you a broad spectrum from the phophor and narrow lines from the mercury discharge. They use a glass which damps the UV lines from the mercury, but they still come through pretty strong when measured on a spectrometer. There have always been questions about the long term safety of those soft UV lines.

It's a shame I can't capture a sensible photo through the small eyepiece. Yes, I was expecting a much more continuous spectrum - ok the lines aren't really thin, as you would see from single element lines but what I see is a band of Red, a narrower band of Yellow, one of green, and a broad band of blue, going into Violet. There are large empty gaps between them though.

The Garage lamp is a relatively old, Argon (low temperature start) Philips 8ft 125W one, but the kitchen one was a relatively new (tube replaced within the last 5 years) 40W circular fluorescent. The colour bands were pretty much identical.

I've since replaced the kitchen one with a nice GE LED dome fixture, and again what I see is a continuous spectrum. It's difficult by eye to distinguish the absolute brightnesses of every part of the spectrum but the thing is that it is a continuous spectrum with no gaps. That's what surprised me.

The filament lamps (actually eco-halogen bulb replacements) have a continuous spectrum (which I would of course expect). There is blue present but no Violet, again as you would expect from the filament temperature.

There are a few modern spectroscopes to be found on ebay, and probably educational suppliers, together with various designs on the web using CDs as diffraction gratings.

[coppice]

I first tried the fluorescent tube lights in the garage and kitchen and was unsurprised to find a collection of very narrow spectral lines, the same with various compact fluorescent ones.

A fluorescent lamp should give you a broad spectrum from the phophor and narrow lines from the mercury discharge. They use a glass which damps the UV lines from the mercury, but they still come through pretty strong when measured on a spectrometer. There have always been questions about the long term safety of those soft UV lines.

It's a shame I can't capture a sensible photo through the small eyepiece.

Photos are useless for this kind of thing. You just capture the spectral response of the camera. You need to use a sensor with a flat spectral response. A lot of professional work is done with something like a rotatable diffraction grating shining through a narrow slit, onto a photomultiplier tube. Photomultiplier tubes can have a very flat response. Then you can sweep the visible band by rotating the diffraction grating, and get an accurate spectral plot of the source light.

Yes, I was expecting a much more continuous spectrum - ok the lines aren't really thin, as you would see from single element lines but what I see is a band of Red, a narrower band of Yellow, one of green, and a broad band of blue, going into Violet. There are large empty gaps between them though.

The Garage lamp is a relatively old, Argon (low temperature start) Philips 8ft 125W one, but the kitchen one was a relatively new (tube replaced within the last 5 years) 40W circular fluorescent. The colour bands were pretty much identical.

I spent a summer holiday when at school doing detailed spectral response measurements of fluorescent tubes in a lab at Thorn Lighting. I never found a tube with any discontinuity in the spectrum.

I've since replaced the kitchen one with a nice GE LED dome fixture, and again what I see is a continuous spectrum. It's difficult by eye to distinguish the absolute brightnesses of every part of the spectrum but the thing is that it is a continuous spectrum with no gaps. That's what surprised me.

The filament lamps (actually eco-halogen bulb replacements) have a continuous spectrum (which I would of course expect). There is blue present but no Violet, again as you would expect from the filament temperature.

There are a few modern spectroscopes to be found on ebay, and probably educational suppliers, together with various designs on the web using CDs as diffraction gratings.

The light from fluorescent lamps and white LEDs both come from similar kinds of phosphor. The spectra produced are not radically different in nature. You should expect a continuous, if rather uneven, spectrum, regardless of which colour lamp you choose.

[james_s]

I had a few co-workers who insisted the florescent lighting gave them headaches. They convinced HR to essentially have the lights off in the office -- which applied to everyone. This wasn't that long ago so they were modern electronic ballasts where your eyes cannot pickup any flicker. Funny thing is, I get frequent headaches too but I don't jump at blaming the type of light bulb. If anything, I feel that sitting in a dark room looking at a bright monitor is uncomfortable. Humans are very prone to confirmation bias so we end up with essentially superstitious beliefs. So LED lights are bad and florescent lights are bad... maybe some people will think incandescent lights and candle lights are bad too.

What I don't like with LED is that many fixtures now come with the LEDs as non-replaceable. I guess people find it convenient but both the LEDs and the electronics have a lifespan and can fail. I much prefer LED bulbs with the Edison screw that can be replaced.

I find the opposite is true for me, sitting in a bright room is uncomfortable, I like to work in subdued lighting, the actual lighting technology is irrelevant.

Some LED backlit monitors use PWM dimming at a relatively low frequency of a few hundred Hz and that gives me a splitting headache. With better monitors this is not an issue at all.

[Gyro]

The light from fluorescent lamps and white LEDs both come from similar kinds of phosphor. The spectra produced are not radically different in nature. You should expect a continuous, if rather uneven, spectrum, regardless of which colour lamp you choose.

That's what I thought but I've been back and checked. No problems with the spectroscope though, as I said, it is clean enough to distinguish Fraunhofer lines (when it's not bucketing down with rain!).

I just remembered another florescent source  - the shop diplay lighting fixture that I used above my workbench before switching to a pair of Lidl LED batten fittings. It uses a pair of Osram white daylight (purchased by me, not specials) PL11 U shaped compact tubes. Again discrete Red, dirty Yellow, Green, then Cyan with a sharp transition to Blue and dull Violet with largish gaps between). There is one very sharp bright violet line at the top end, presumably the Mercury line. Any other lines must be hidden by the phosphors.

Needless to say, the Lidl centre isle LED battens have a nice continuous spectrum! 

Edit:

I spent a summer holiday when at school doing detailed spectral response measurements of fluorescent tubes in a lab at Thorn Lighting. I never found a tube with any discontinuity in the spectrum.

Maybe it's an artifact of moving to more modern Tri-phosphor coatings in the quest for increased efficiency? (Just picking up on the Thorn reference).

[Kean]

If I was the OP, I'd be visiting my optometrist rather than sitting in front of a computer and posting on a forum.

[scatterandfocus]

If I was the OP, I'd be visiting my optometrist rather than sitting in front of a computer and posting on a forum.

Been there done that.  He told me that there is nothing wrong with my vision that he is able to test, but that if I would like, he can prescribe me some blue-light blocking lenses with a slight magnification for computer use....wich are basically Gunnars or other brand. 

[coppice]

I spent a summer holiday when at school doing detailed spectral response measurements of fluorescent tubes in a lab at Thorn Lighting. I never found a tube with any discontinuity in the spectrum.

Maybe it's an artifact of moving to more modern Tri-phosphor coatings in the quest for increased efficiency? (Just picking up on the Thorn reference).

Most of the phosphors I worked with in the 70s at Thorn already used multiple rare earths. One of my tasks was to measure sample tubes of various colours off the production line, to check that their phosphor mixes were staying in spec. Supply a few truck loads of off colour tubes to a clothing chain, they get massive returns of the "it didn't look this colour when I tried it on in the shop" kind, and people lose their jobs. Look at the example rare earth spectrum at https://en.wikipedia.org/wiki/Fluorescent_lamp . There are no gaps in that. Each of the rare earth phosphors has quite a wide spectral spread, and they overlap.