Maxx Yes, this is clear, the spectrum favors blue light. But the blue light from a screen is 1 and the blue light from the blue sky is 100 or more. So even if the spectrum favors blue, I don't buy the idea that it would irritate the eyes.

I've personally seen flicker free blue LEDs on certain electronics of bright intensity, and it's not very pleasant to look at.

I don't buy that even in the case of a flicker-free display with no dithering that "everything is entirely fine, move along", hence the drive for more research.

Or what if a person is in a room painted blue lit by blue light. I don't think there would be any eye strain

I mean, this kind of brings back an earlier point of mine. CRT monitors had a more even spectrum compared to "modern" WLED backlights, and I don't recall people obsessing over color temperatures with those.

I think that in most cases they have just mixed flicker with blue light as the flicker is something (temporal dithering) that cannot be [measured].

Could you detail your rig how you video temporal ditering?

There are still many unknowns with the dithering problem, one being that the display outputs on a laptop versus the connection used for the internal LCD do differ, so it's not trivial to reliably detect dithering on a laptop as using the internal LCD.

I haven't written up all my notes and testing, but here's some info on my project "VideoDiff"

https://ledstrain.org/d/848-project-videodiff
https://wiki.ledstrain.org/docs/appendix/tests/dithering/

    @JTL Yes, I agree that staring at a blue light for hours every day might not be good for eye or sleep health. So I agree that the lightspectrum should be as close to natural sunlight as possible.

    But does the blue light spike in the spectrum actually cause any significant eye strain? Not at least for me and presumably to most people, since most people do not experience any eye strain from any screen, even with PWM or Temporal Dithering.

    So that's why I argue that the marketing BS about blue light is misleading as it tries to connect blue light to eye strain, while most people do not experience any eye strain with screens. Those who do, the cause is most of the time PWM or dithering.

    I was thinking if the dithering could be detected by purchasing a cheap microscope and filming that with a dlsr or even mobile phone.

    JTL I once read a paper from the "lighting industry" that claim that some of the effects of PWM persist up to around 10KHz, but I'm not entirely sure of the methodology involved.

    This may have been a reference to this 2011 paper by Bullough et al. where 20% of people could still notice the stroboscopic effect of flicker at 10,000Hz. They did not test higher frequencies, so did not determine at what frequency no one can detect flicker. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.876.126&rep=rep1&type=pdf

      hi, i use the razer studio 2020, with the quadro 5000, older driver, but the screen is pwm free, one of the very few. maybe test it as it works for me really well.

        @Phip Is it the OLED version - that surely cannot be PWM free?
        Are you in the same situation that PWM AND temporal dithering is a problem?

        • Phip replied to this.

          Just realized that my HP ZR2740w is a 10 bit (8+2 FRC) so Temporal dithering? I don't know. But this monitor has given me zero eye strain for the past 10 years no matter how much I used it and with what kind of hardware.

          The only thing I can think of is that I have some 5 years old Nvidia 970 card - maybe that then did not yet have the technology that the newer ones have, which is producing the eye strain in more recent laptops?

          Oh what a frustrating problem this is. I may need to start hoarding old Lenovos to be able to work eye strain free when not at home.

          So a bit an addition to the above - now I'm quite baffled on why the HP display is completely eye strain free, as it DOES have temporal dithering.

          What can be the cause, since it is not Windows version, using Ubuntu or different display adapters?

          What gives? What could be the source of irritation in all of the laptop displays, since PWM is overruled and the Desktop HP monitor does not give eye strain even though it has temporal dithering?

          How can this be so difficult to find out what gives the eye strain apart from PWM?

          Could it be the way the FRC is implemented? It does not seem to be the latency of the panel, since the HP panel is quite fast and can be used for gaming.

          Does anyone have any idea?

            There are tens of threats when I search. Any chance someone could tell what it is and what might be the assumptions so I would not need to spent hours investigating this?

              Maxx No, because there is no one singular cause that applies to every individual.

                Could you please try to re-evaluate your position. If LCD inversion is a problem, there needs to be similarities as to why it is a problem for those affected. Saying it is individual, just does not make any sense.

                If we keep cultivating the idea in this forum that displays cause completely random issues for every individual, there is absolutely no hope to find any kind of solution and we could as well stop the discussion.

                We need to try to be more scientific to this problem and have some categories on the source of problem like:

                PWM is absolutely and scientifically confirmed to be a problem for some. Reason: flickering light irritates the eyes, because the optic nerve senses the flicker, even if we are unable to actually see the flicker.

                LCD inversion is a problem for some. Reason:? (flicker also?)

                FPS games are a problem for some. Reason: unnaturally fast action without actual movement cause motion sickness, similarly like in sea sickness there is the opposite, movement without perception of movement. (in sea sickness gazing to the horizon helps, as then the brain also sees the movement that is felt by the body)

                Temporal Dithering - now I'm unsure whether it is so simple anymore. Like I wrote earlier, the HP display that has been problem free for the past 10 years, does have temporal dithering. So maybe it is a certain way the Dithering is implemented, that produces the eye strain...

                but please, do not give the impression that this is a completely individual problem where everybody has a different reason why they can't use a certain display. This cannot be the case. We just have not been scientific enough in our testing and do not seem to have adequate understanding of the technologies, nor eye physiology.

                2 months later

                Maxx

                Yes OLED and the only PWM free screen on market I think. I tested it seems to be correct. And feels great to use.

                    2 years later

                    Hi @Maxx, one question, do you get symptoms with screen that have high frequency PWM, like for example 5000 HZ ?

                    Au Optronics panels or Innolux are the best choice.

                    Avoid BOE.

                    In fact I need to sell my Zephyrus G15 boe panel, It's flicker free and it hurts my eyes.

                    All Au Optronics choices are good for my eyes.

                      Phip Oled does not use pwm but it flickers too, and to me is worse than pwm.

                          Abeabe I don't trust in oled flicker free. It's marketing as LG OLED TV certified flicker free by Tuv Rheinland, but all of these have flickering (watching by Phone Camera)

                            6 days later
                            dev