
LED Strain - profdithering
http://ledstrain.org
======
sydd
This is one of those topics that I researched a lot when I bought a new home
recently. While LED lights seem awesome at the first sight (low power
consumption! No warmup time!) when you dig a little deeper you'll find that
most LEDs are far from perfect:

1\. Lots of LEDs flicker. Shitty ones with twice the frequency of the main
current (so 100/120 Hz) While you might not notice this it causes eye strain
and can lead to eye fatigue, headaches, migraines.

2\. Most LEDs have a low CRI (Color Rendering Index, or called Ra which is one
standard to measure it), this means that they do not emit light in certain
frequencies causing objects to look dull/gray. Most LED lamps have a Ra value
of 80, meaning that they emit on average in the 80% of a spectrum that covers
most of the visible light.

If you look around you'll be able to find reasonably priced LEDs with 90+ Ra
and no flicker, but its a pain in the ass to research it. Especially if you
need something more special like a LED light strip for your kitchen.

~~~
posterboy
> 1\. Lots of LEDs flicker.

No, the diodes don't, the drivers do. You are speaking to a technical audience
;)

> means that they do not emit light in certain frequencies causing objects to
> look dull/gray. Most LED lamps have a Ra value of 80, meaning that they emit
> on average in the 80% ...

Hardly. It means that they reproduce a set of 8 or 16 fixed frequencies from
the ral pallete. It doesn't cover anything inbetween so it's just a rough rule
of thumb. It doesn't cover colors in the far red (or was that violette on the
other end of the soecteum?) at all.

Overall, overexposure of some frequencies, arguably to appear brighter and
fuller, has damaged musuem pieces--Radiation stress, really. All they can do
now is individual tests with photometric instruments, because they can't trust
CRI. Same for horticultural lighting, which hasn't really taken of anyway.

Edit: Some manufacturers publish reference curves in the datasheets for their
emitters, however I don't know how accurate these are under varying conditions
and across batches.

~~~
darkmighty
Having made a cheap DIY spectrometer[1], I found the spectrum of LED around my
house quite good, not completely smooth as sunlight, but smooth enough (you
can gain some efficiency for not being totally smooth by better matching eye
receptors). It's a far cry from fluorescent spectra that have extremely sharp
concentrated spectra (and I suspect the risk from narrow spectra of causing
biological damage is greater, since it could in theory disrupt very
efficiently some molecular energy transition that happens to be well matched
with that frequency).

[1] See e.g. [https://ocw.mit.edu/courses/electrical-engineering-and-
compu...](https://ocw.mit.edu/courses/electrical-engineering-and-computer-
science/6-s079-nanomaker-spring-2013/labs/MIT6_S079S13_lab_slides01.pdf)

[https://lavinia.as.arizona.edu/~mhammer/outreach/cdSpectrome...](https://lavinia.as.arizona.edu/~mhammer/outreach/cdSpectrometerWorkshop.pdf)

(diffraction spectrometer from used CD/DVDs, very easy to make, and it costs
~$0)

~~~
fudged71
If you want to check for flicker, there is a great app called VISO Flicker
Tester

~~~
jelder
Unfortunately the app seems to be broken on iPhone 8+. Fails with "App could
not detect camera."

------
joecool1029
'Is It Snappy?' is an iOS app that I use to diagnose whether LED bulbs are
going to be shit in stores before I buy them. The IKEA bulbs have been cheap
and decent.

Old HN thread about the iOS app:
[https://news.ycombinator.com/item?id=14023196](https://news.ycombinator.com/item?id=14023196)

~~~
wlesieutre
FWIW I bought four IKEA bulbs a few years ago and all of them made a low
buzzing sound. Couldn't stand them anywhere but the bathroom.

On the other hand, if you're looking for IoT light bulbs, their Tradfri system
is a lot cheaper than Hue and I've read that their gateway has reasonable
security practices and a good API. I would bet that those are more premium
products that they wouldn't have released without making sure the electronics
are quiet.

~~~
joecool1029
> FWIW I bought four IKEA bulbs a few years ago and all of them made a low
> buzzing sound. Couldn't stand them anywhere but the bathroom.

LED or CFL? The latest batch of LED's they've only had about a year, the
phosphors were switched around in their 1000 lumen (lm) and 1600lm E26 bulbs.
They also advertise 100lm/W.

These are not the junky dirt cheap 80lm/W 60W (800lm) equiv bulbs that you can
pick up everywhere now (and I don't recommend for lighting a room).

Also, watch for open boxes, I bought ~$200 in bulbs last time and one of the
globe bulbs I bought was an obvious return and did not work.

------
Zak
I _hate_ lighting that flickers and will often notice it when other people do
not. A few friends also notice flickering that most people don't detect. It
takes tens of kHz before I won't notice a stop-motion effect like a strobe
light with moving objects.

LEDs do not have to flicker, but supplying low-ripple, constant-current DC
power is not as cheap as ways of powering LEDs that do result in flicker.

~~~
Johnny555
I rarely notice PWM strobing with most LEDs at home.

However, once place where I do notice it and it's annoying is with taillights
on some cars - sometimes when I sweep my eyes across the cars ahead, I see the
strobe effect from LED taillights.

It doesn't seem to happen with all cars.

I've noticed it in a few bike taillights, but not nearly as much as in cars. I
used to have an early LED bike headlight, and the strobing was very apparent
when the light was dimmmed, I could only use it at its highest level.

~~~
fyfy18
I recently walked along a road with some Christmas lights (installed by the
city) with the most horrible flicker. When looking at them straight on you
could just notice it, but from the corner of my eye it was really bad and
distracting. I wonder if there have been any studies done on the dangers for
drivers of LED flicker.

------
kweks
Last year, I was contemplating bootstrapping a startup that sold full-spectrum
LEDs with a controllable blue element for home and office use. Think Flux but
for real lights.

I got so far as inspecting factories in Shenzhen, finding a partner supplier,
and building some prototypes with my existing manufacturing contacts.

Ultimately, I ran out of time (launched another product instead) - but it
always bugged me that I wasn't able to bring this product to market.

If anyone would be interested in picking up where I left off - I'd be
interested in partnering.

Shoot an email to public @ proxmark dot com

~~~
warp
I've used Philips Hue lights for a sort-of-flux for my office, it works fairly
well. The hardware part of it seems like a solved problem with the
availability of RGB smart bulbs (or the cheaper ones which only go from
cold/blue-ish light to warmer orange light, without full RGB).

The software side could be improved.

~~~
yeutterg
I use Hue at home as well. They are great for controlling blue light exposure,
but the flicker (North America) and color quality leave a ton to be desired. I
can occasionally see the flicker, especially in my peripheral vision.

Also, they've proven to be unreliable—I've had 4 (out of 13) suffer capacitor
failure just outside of the warranty period. Their color binning is not
good—new lights look totally different in color from the older ones.

I wrote about this and was interviewed on a podcast recently:

* Is Smart Lighting Healthy?: [https://medium.com/simplebulb/is-smart-lighting-healthy-903c...](https://medium.com/simplebulb/is-smart-lighting-healthy-903ccc81c42b)

* Podcast: [https://bedtimebulb.com/ror](https://bedtimebulb.com/ror)

Disclosure: I sell a light bulb meant to be used in the evening before bed. It
removes most of the unhealthy blue/green light, has a super high CRI, and has
less flicker than "flicker-free" lighting (which could have up to 30%
flicker!). Bedtime Bulb: [https://bedtimebulb.com/](https://bedtimebulb.com/)

------
Fnoord
In The Netherlands some cyclists have this brilliant idea to put their lights
on flash/flicker. I suppose some think they'll be easier to get noticed.

It is not allowed by law (the light has to be either constantly on, or it may
be turned off if it isn't dark), it can trigger epilepsy, it is distracting,
and it is selfish and not 'cool' at all.

It also appears to be common in PC desktops to enable all kind of LEDs,
without allowing them to be disabled. Especially in all kind of colours (which
Razor dubbed 'Chroma'). Not my cup of tea, a waste of aesthetic and
electricity but the worst thing about it is that I pay premium for such
feature because it is deemed 'cool' by the target market.

FWIW, I use a strong light in the morning to wake up. It doesn't flash.

~~~
Steve44
There are quite a lot of these in the UK too, again I'm not sure of the
legality.

As a driver I've two things to say about them.

Firstly, they do make it easier to spot the cyclist over a solid light so
that's a good thing. However, it's almost impossible to track their movement
and that is a very very bad thing.

The best solution I feel is to have a flashing light which draws attention in
addition to a solid light which is much easier to keep track of in your
peripheral.

~~~
4ndr3vv
The rules in the UK have changed somewhat over the years; it used to be that
flashing lights were only permitted in addition to a constant lamp.

Now its fine to only use flashing lights - Rule 60 of the highway code:

 _" At night your cycle MUST have white front and red rear lights lit. It MUST
also be fitted with a red rear reflector (and amber pedal reflectors, if
manufactured after 1/10/85). White front reflectors and spoke reflectors will
also help you to be seen. Flashing lights are permitted but it is recommended
that cyclists who are riding in areas without street lighting use a steady
front lamp."_

~~~
Already__Taken
With the insane brightness now possible I wish they had to meet the same light
pattern rules car headlights do. I think that would help the flashing being so
distracting.

~~~
rootusrootus
I occasionally run across bicyclists now with modern LED lights that are more
blinding than automobile headlights.

~~~
rhinoceraptor
A very bright bike light makes it much more comfortable to ride a bike at
night, you need to compete with car headlights so that you can see the surface
of the road in front of you. Cars don't need to worry about the road
conditions as much as cyclists since if they hit a pothole or a stick, it's no
big deal.

~~~
rootusrootus
I'm hoping cars (and bikes) evolve over the next few years into less blinding
headlights. The infatuation we have with projectors makes even halogen lights
blinding. I see some newer Acuras coming with multiple LED projectors on each
side lately, which ought to help (so long as overall output is constant, and
each projector is dimmer)

------
jeremy7600
This should be flagged, tagged, or somehow made to be seen by new vistors to
the site, as I had to track this down to figure out what this site was even on
about.

[https://ledstrain.org/d/19-welcome-to-led-
strain](https://ledstrain.org/d/19-welcome-to-led-strain)

------
lorenzk
I was impressed by how fast and uncluttered this site is. In case someone else
is wondering: It seems to be running
[https://flarum.org/](https://flarum.org/), a PHP forum with a Mithril JS
front-end

~~~
petra
Nice UX.

But it's terrible for search, both internal and external(Google).

Why ?

Let's start with internal search. Ctrl-f fails in thread search. No other
mechanism to search inside a thread.

And about external search:

Permalinks to individual comments - great for the search engine when you
request a very specific thing - a specific niche comment from this site could
get ranked highly in google.

Also, it's making it easy to link to a great comment is import. Impossible
here.

Permalinks to webpages that contain full threads - lots of relevant text for
the search engine to chew on. But in flarum the content lazily loads. So maybe
Google wouldn't be able to chew on all the comments.

And the fact that when Google finds a thread from the site, he doesn't say how
many comments per thread , indicates that he doesn't see this as a forum,
which could be bad

And all this is a real shame - it's a community with really valuable content.

~~~
KajMagnus
Then can I ask, what do you think about this? from the point of view of
external search?

Topic list:
[https://www.talkyard.io/forum/latest](https://www.talkyard.io/forum/latest)

Example long discussion: [https://insightful.demo.talkyard.io/-11/my-son-was-
sent-home...](https://insightful.demo.talkyard.io/-11/my-son-was-sent-home-
from-sleepover-for-bad-behavior) (of a length that might work less well with
sort-by-time + lazy-load approaches)

It's also new forum software (I'm developing it), sort of a combination of
Discourse and HN and Slack. I would think it works ok with external search?
Becasue, like here at HN, good comments surface to the top, + they're included
in the HTMl directly on page load. So, what a search engine sees, ought to be
the original post, + the best comments.

I'm wondering, what do you mean with: _" Also, it's making it easy to link to
a great comment is import"_? (What does "import" mean, here)

~~~
petra
import = important.

1\. the way you do permlinks to individual posts looks good. It's also easily
shareable. good too.

2\. but probably, an even better way to do permalinks is something like quora
did - just the specific answer that solves the user's problem , in a seperate
non-distracting page, with a full, human readable url.

That of course creates a problem with sub-comments, but quora solved it nicely
by hiding them .

[https://www.quora.com/Google-categorized-me-as-T4-The-
offere...](https://www.quora.com/Google-categorized-me-as-T4-The-offered-
me-140k-base-15-bonus-30k-stock-20k-signup-bonus-I-have-competing-offers-from-
startups-with-190k-base-and-400k-equity-all-vesting-over-four-years-Does-
anyone-have-an-explanation/answer/Richard-
Bielak?ch=10&share=a22655b0&srid=OyM)

3\. Content quality is key for SEO. Assuming that upvotes works well for that.
i don't know much about forum design, but i assume upvotes are really
sensitive to the community and that's why HN is so great.

but in other communities, i wish there was a way to sense if "this answer
solved the issue" or something similar, and letting that rise. That's probably
one of the reasons stackoverflow won.

But forums are somewhat different so that's harder.

4\. Adding that "recommended links" on the site could help SEO. but it's a
shitty user experience. So probably isn't worth it.

~~~
KajMagnus
Thanks for the feedback. Interesting to see how Quora does answer permalinks.
At the same time, then _other_ answers, aren't easily discoverable.

Yea, upvotes only work, if the community "collectively" has a good judgement
:- ) Also, I'm thinking about weighting upvotes, with how good a judgement the
voter seems to have, based on trust levels and fraction upvoted and downvoted
answers, hmm. So a staff user's or a trusted core member's upvotes, have a bit
more weight, than votes from a new and unknown person.

------
sephamorr
Let me shed some light on how you can drive LEDs from an AC power source.
Naturally the worst techniques are usually the cheapest. To add to the
complexity, directives like EnergyStar are aiming for power factor >0.9 in
lighting above 3W. Maintaining high power factor (sin^2 input power) while
having low lighting ripple (constant output power) requires some method of of
storing energy. In methods 1,2,3 (and 4 depending), neither high power factor
nor good lighting ripple is achieved, but very low cost is.

Note that this info is for fairly low power LEDs. When you start having high
power LEDs, regulations may require better power electronics, and the cost of
the electronics might be amortized against the cost of the thermal cooling
solution, etc, so you can make a more expensive electronics package.

1) By stringing ~ 180v of LEDs in series, and adding a current limiting
resistor, you can drive the whole thing from the AC line. This has terrible
variability (short light spikes every 60hz, and the thermal effects will
change the LED properties so much that you could easily have 2x light
intensity change as they warm up) and poor total illumination (as most of the
cycle is spent with the AC waveform lower than the needed voltage. I haven't
seen this in the wild, as option 2 isn't much more expensive and far better.

2) Use a single diode + capacitor rectifier to generate ~180v, and then have a
similar string as in (1). This gives far better illumination (the capacitor
will probably stay in the 160-180v range), but still has substantial 50/60hz
ripple based on the size of the capacitor

3) Similar to (2) but use a full bridge rectifier instead of a single diode.
As we are now driven by a rectified sine wave, the ripple voltage will ~half,
and the ripple frequency will now be 100/120hz.

4) Many applications don't have ~60 LEDs in series, so you can't drive
directly from the rectified AC line. The first stage is a rectifier, and a
second stage most likely is a buck converter. The quality of the light out of
this depends on how much you care about power factor. Chips like NCL30288, for
example, maintain high power factor and fairly low lighting ripple. Most
people won't notice this.

5) Particularly in higher power lighting, a separate power factor correcting
stage achieves high power factor, and a second stage generates a constant
current that should have exceptionally low luminous intensity ripple (if
designed right). The ripple frequency should be in the hundreds of kHz as
well, so I don't think any eye could notice this.

And don't get started on dimming, I haven't found a product on the market that
does non-phase cut dimming in <20W lights.

~~~
Doxin
6) use any of the above methods but with UV leds and coat the glass on your
bulb with phosphor, giving some extra buffer to the flicker by way of a slow
brightness decay.

I'm fairly sure the IKEA bulbs use the above method. If you turn them off they
have an afterglow for a couple seconds.

~~~
jacobush
I always assumed that was the capacitor draining.

~~~
Doxin
Could be, but then there's also the CRI rating on these ikea bulbs being
rather good at around 95.6 which hints at phosphor as well.

I could be entirely wrong though, someone should probably dismantle one and
figure it out.

------
chris_overseas
One interesting use for flickering LEDs is to help figure out the readout
speed and clock rate of a digital camera sensor by exploiting the rolling
shutter. Some discussion and experiments on this technique can be found here:
[https://www.magiclantern.fm/forum/index.php?topic=23040.0](https://www.magiclantern.fm/forum/index.php?topic=23040.0)

------
jcims
Tis the season for PWM-induced headaches from cheap LED Christmas lights.

I'm curious if folks in countries with 50Hz mains have the same issue. At that
point it might be so bad that products without at least a full bridge
rectifier would be unsellable.

~~~
pitaj
Pretty sure PWM has nothing to do with cheap LED Christmas lights, beyond the
basic "periodic wave resulting in flickering" idea.

~~~
Tharkun
Many xmas lights flicker, even when they're not in blinking mode. With the
really crappy ones it's often noticeable just by looking at them. With some of
the slightly less crappy ones, it's easier to notice when looking at them out
of the corner of your eye.

------
JKCalhoun
Interesting. Reading some of the comments they really run the gamut (no pun
intended). It's reassuring to see though that people are starting to pay
attention to this. For myself, it is the flicker (PWM) of some LED drivers
that I am uncomfortable with. I went through a few different brands of LED
track lights before finding one where I could perceive no flicker.

Similarly for LED lightning in the garage.

For the kitchen I had a need for rope lighting and never did find LED/driver
combo that I was happy with.

~~~
copperx
Here's a trick that I've found useful: If you have a phone that can do slow
motion capture (I have a Pixel 2, but this also works with an iPhone), go to a
Home Depot or Lowe's and take a slo-mo (240fps) video of the LED bulbs they
have on display. Most flicker horribly on playback, including the expensive
Cree bulbs.

The built-in LED spotlights that came with my house flicker like a rave
concert whenever I capture a video in slo-mo. It's unsettling.

Phillips LEDs, especially the Scene Switch bulbs, are flicker-free according
to my tests. Surprisingly, older CFL bulbs flicker much less than LEDs.

~~~
homero
CFL stay semi lit between cycles

~~~
akronate
Former product display engineer here. Many of those light bulb displays are
only meant to demonstrate color temperature, and have completely different
power systems on board then an actual light bulb. Usually the AC rectification
will be removed and replaced with a DC/DC converter.

This is mostly so that the display can be battery powered, because the
availability of AC power on shelf is pretty hit or miss. I wouldn’t trust a
display to indicate if the bulb has flicker or not.

~~~
copperx
The ones you're talking about demonstrate color temperature. The ones I've
seen demonstrate the different light output of different brands and are
connected to AC through a dimmer. You can play with the dimmer, and the price
of the dimmer (each dimmer is different) and the bulb are displayed.

I can't imagine those are battery powered or that every different bulb on
display has been modified.

~~~
fenwick67
This makes me wonder what the dimmer might be doing

------
fenwick67
PWM is noticeable on most 7-segment displays (on microwaves etc).

Clicking your teeth together makes it pretty apparent usually, the segments
will appear to jump around. Try it at home!

~~~
kw71
This is not that. This is multiplexing and the purpose of it is to save i/o
wires. If you film it with a high speed camera you will see something like one
digit being lit at a time.

~~~
fenwick67
Yeah you're right, calling it PWM isn't really correct.

------
fermentation
This is interesting. If LED lights pulse so quickly that we don't notice the
flashing, how are these people able to perceive it in a way that causes them
pain?

~~~
ChuckMcM
Different parts of your eye are attuned to different frequency responses. For
me, it is easier to see flicker in my peripheral vision rather than my direct
vision, so if something is off to the side it can be more annoying than
something right in front of me.

That said, I can eliminate all annoying flicker by making sure that all of the
things that flicker aren't mixing down into ranges that start to annoy me. For
example if you have some LEDs that are running at 15Khz and some that are
running at 15.1Khz they can set up a beat frequency at 100Hz that is annoying.
I had some dimmable can lights that did this and figured out that the PWM was
local oscillator based (R/C if you can believe it) rather than crystal based.
I found lights that used the line frequency to drive their oscillator so they
are essentially all in sync (at 2.4KHz or so, so not noticeable to my eyes)

~~~
Someone
_”For me, it is easier to see flicker in my peripheral vision rather than my
direct vision”_

That applies to (about) everybody, for large enough stimuli. Rods are more
sensitive to flicker than cones and you don’t have that many rods in your
fovea. See
[https://en.wikipedia.org/wiki/Flicker_fusion_threshold](https://en.wikipedia.org/wiki/Flicker_fusion_threshold).

------
2700K
I Learned that if low freq LED flicker strains your eyes, then there's a
chance you'll feel discomfort from emerging display HDR color dithering as
well. For example, if the panel is 8bit but it shows you 10bit color space by
8 bit plus A-FRC.

Bought a 2018 Macbook pro and it produces similar symptoms like years ago when
I had a laptop with bad low freq LED backlight.

Right now using a late 2010 and a 2013 Macbook Pro both with native screens
and on external screens and it does not make my head hurt. 2018 one strains me
both on native screen and on my otherwise good daily driver BenQ monitor.

~~~
jtl999
What GPU and OS X version are the older Macbook Pros?

------
ksec
Related Question: Is it possible for AM-OLED to be PWM free? ( Apart from
setting it at maximum brightness ). Or would we have to stick to this until
MicroLED comes.... which is still years away.

Edit: I know W-OLED used by LG does not have PWM problem, but that is not for
mobile uses.

~~~
discreteevent
There are a few of interesting comments in this thread:

[https://www.reddit.com/r/apple/comments/7uv6m3/iphone_x_uses...](https://www.reddit.com/r/apple/comments/7uv6m3/iphone_x_uses_pulse_width_modulation_which_is_a/?st=JM3ZG0DU&sh=d12d2cf9)

In summary they are saying that low frequency (240Hz) PWM is used for amoled
because it decreases sub-pixel wear, it prevents color distortion, it's
cheaper. So it looks like this won't change. I got an amoled phone and was
surprised that the experience was worse than LCD (for me - it seems to depend
a lot on the individual). Didn't even know that PWM was used until I started
googling eystrain and amoled. Anyway, I sent the phone back.

~~~
ksec
That is sad, I wish they do 480hz and we could see if it strain as much.

------
LargoLasskhyfv
I'm sensitive to this flickering as well. Cars in motion, traffic lights,
destination/passenger information displays, POS, sometimes ATMs. Though the
"car-thing" mostly faded away over the last few years. They seem to got that
right now. Anyways, i tried some of them over the last decade and they were
all trash, made bad light, needed time to warm up, had coil whine or buzzing
and broke after a few months. Then in May this year i tried some again and
they were absolutely OK. It's called "LED-Retrofit" which means it fits in old
sockets, based on this technology:
[https://en.wikipedia.org/wiki/LED_filament](https://en.wikipedia.org/wiki/LED_filament)
No dimming, no "smarts", no color/ambilight etc. Just works as it should. Mine
are from Osram, for something like 6 to 12 Euros a piece, directly plugged
into E27/E14 sockets at 230V@50Hz. And most importantly no ugly interactions
with my screens running at 60Hz. This reminds me of scissors, for a long time
they needed to be resharpened. Then, since maybe two, or at least one decade
ago you could get good and f......g dangerous scissors which cut through
almost anything whitout getting blunt/dull for next to nothing. Now seems to
be the point in time where this happened for LED-lighting. At least when it's
based on this "LED-Filament"-thing. HTH.

(edit spelling)

------
baybal2
What is this about? Can't quite get the point what this is about

~~~
jeremy7600
I finally found this post, which is clearly missing from the FAQ:
([https://ledstrain.org/p/1-faq](https://ledstrain.org/p/1-faq))

[https://ledstrain.org/d/19-welcome-to-led-
strain](https://ledstrain.org/d/19-welcome-to-led-strain)

------
crankylinuxuser
And I still like my incandescent light bulbs.

Sure, when the AC is on in late spring/summer, LED makes a heck of a lot more
sense. But when the heat is on, filament lightbulbs serve as space heaters as
well as glowy-warm lights.

And with the whole open question of blue light and retinopathy, tells me that
until this is resolved that again, incandescents are better than LEDs. I
already knew that those damned 'blue LEDs' are painful at night. I now know
why.

~~~
vostok
Heat pumps are usually more efficient than incandescent bulbs at heating.

~~~
crankylinuxuser
True, but in the cold parts of the year, those lights are 100% efficient. They
provide light (primary), and heat (secondary).

Its only during the warmer parts of the year do they turn into a significant
burden, energy wise.

~~~
vostok
Right, but 100% efficient is pretty bad. Heat pumps can be 300% efficient for
example.

------
33degrees
As someone who suffers from this since the arrival of LED backlighting, I
wonder if there are lighting technologies on their way that will eliminate the
issue?

~~~
joshstrange
I'm not an expert but IIRC OLED doesn't use backlighting correct? Do OLED
screens also cause you strain?

~~~
33degrees
Correct, OLED doesn't use backlighting, but the problem is the PWM used to dim
pixels, which is also used on OLED displays. I haven't tested the difference,
but I've read that for others OLED in and of itself doesn't help.

------
posterboy
Built-in converters for retro fit are such a waste. An external converter is
small enough to build into the enclosure and industrial setups do just that.

------
Tharkun
I don't see the word 'migraine' mentioned anywhere on the linked site?

Update: the title has since been changed to 'LED Strain'.

------
yc2051
The LED tubes that are being used to replace the florescent tubes are much
brighter! This could also be a source of migraines.

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posterboy
I wonder whether flicker decreases lifetime significantly enough to eat up
even the supposed savings.

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fireattack
LED strain could be a real thing but I'm not sure if this forum's discussion
is scientific enough to be meaningful.

