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  • Jessiah1 Level 1 Level 1

    One other thing I forgot to mention, I am attempting to pursue Flicker and spectrum through scientific method. I have a meeting with a light doctor coming up and I also plan to contact the Boston Photonics center where they research this very subject. We need to take this past the display companies because this is NOT their area of expertise. Unfortunately problems that combine science and health are very difficult to solve and you need several participants from both the medical field and scientific field to work together, thus the Boston Photonics centers.



  • mojarvinen Level 1 Level 1

    Jesse - great that you are looking into this in more depth.


    Might be true that I'm in the minority here. But if you allow me to point out, that if people just get moderately irritated eyes that can be sometimes resolved with eye drops and sometimes by not using monitors for a while, they most likely are not on the forum complaining.


    I'm here because I like gadgets, I work with computers and I do photography, which also requires a lot of looking at a display, so if the display irritates, it is a problem. Someone else might have similar issue, but only uses a computer for say 4 hours in the work, otherwise sitting in meetings not really staring a computer screen, thus the problem does not present itself so agressively.


    But your suggestions for the red eyes - I tried to convey the information, that now that I have flicker free displays, I have zero eye irritatio, no red eyes thus no need for eye drops or supplements. So the problem is not the lack of blinking. I've also for the past 20+ years taken a high quality Omega-3 supplement, but that is irrelevant.


    So if you see my point - no red eyes, no irritation with a flicker free display. I'm surely not going to start using eye drops or taking supplements to stand a bad display, and this is exactly the message that needs to go to the public as well. I'd again suggest, though not based on scientific fact, that many people with red irritated eyes are suffering exactly of the flicker, not lack of blinking. This is exactly what drives me nuts with eye doctors, when they suggest to use moisturizing eye drops or to blink more often, when that is just a workaround not a fix. Also, it really is not even a workaround, since when I'm using a display that flickers, no amount of eye drops or supplements help - I will wake up with red eyes that feel irritated, dry and swollen the next morning, if I've had to use a display that flickers the day before. Then they eyes are so irritated that even applying mosturizing eye drops just irritates them more. But if I don't use a flickerin display for a couple of days, problem goes away permanently - until I use a flickering display.


    I have now tried this as I said, 20+ years, so I'm fully on top of this issue on my own behalf.


    One thing I wonder about the blue spectrum - as there are special blue filtering glasses that are confirmed to filter out the blue, why does that not help the people who suffer for the blue spectrum? I know that it is not a solution, you cannot sit around in the office wearing orange/yellow protection glasses, but at least one could try it at home. If the glasses would remove the problem with a 100 % flicker free display, (which without the glassess irritates) then you'd know that it is the blue spectrum for sure. Then the solution would be to use some kind of blue filtering layer on your screens. That of course would not be tolerable if you are into photography, but if you cannot tolerate blue light, then I guess you cannot tolerate looking at images with accurate color reproduction on a LCD screen.



    But great that you have contacted Boston Photonics. As with the flicker, I'm sure that if there are displays with uneven amount of blue light, equalizing the light spectrum would benefit us all. The more natural the better.

  • spprt Level 1 Level 1

    Hi mojarvinen,


    earlier you mentioned the ZR2740w. Is that the monitor you are using now without problems? I wake up with red eyes, too, after having used a flickering monitor or other source of flickering light. I searched for said monitor, yet it appears to use FRC, of which I'm not sure if it may cause eye strain, too. Or can you turn it off from the OSD menu?


    I currently tend to believe a good monitor uses a true 8-bit (or higher) panel without FRC, a backlight without any form of PWM (not even at extremely high frequencies), and no flickering power LEDs. If blue light is of importance, then maybe GB-r-LED or much yellow phosphor might help, too. I didn't find such a monitor yet. Maybe my old iPhone 4 comes close to this.

  • mojarvinen Level 1 Level 1

    Hi spprt


    Yes, that is the monitor that really causes zero problems no matter which brightness it is set to.


    In the evening I many times set it to lowest brighness and migh play games like Battlefield for hours, without any eye strain. There is no OSD menu, at least the model I have. I'm not familiar with FRC though.


    This monitor is great for photography as well, because when I calibrate it with Spyder, the colors are really accurate. This model is the version 2, which has less agressive antiglare coating. The coating cannot be seen at all. The previous anti-glare appeared to be a bit harsh, but this is perfect.


    I can also use Galaxy S2 without problems. Also a Samsung SA850 at full brightness, but that I would not recommend, because the full brighness is a bit too much in the evenings, yet causes no eye strain. It's just generally not good to look at bright lights in the evening, as it will mess up the circardian rythm. (your brain thinks it's day)


    But the HP does not have any kind of flicker with any of the tests that I know of, also it has been confirmed that it is flicker free by LCD review sites and to not contain PWM.  It's also a good monitor for gaming, if that should interest you, as the input latency is somewhat low.


    Yes, the red eye problem is frustrating - I've sometimes been asked, wheter I've been crying or have a hangover as my eyes are blooshot in the morning, though it's just the result of using a bad monitor.

  • soundstar3 Level 1 Level 1

    Hi mojarvinen, do you think the dell u2414h will also work good as the hp zr2740w? Its also flicker free screen.

  • Jessiah1 Level 1 Level 1

    mojarvinen, good inputs, I am glad your here trying to help people and I am sure you may help some people here with similar issues to yours. I can certainly agree with you that flicker is a big part of the issue, unfortunately for many people here eliminating flicker has not solved their issue so why is that? We have a lot to learn I believe and from what I hear since LED's were introduced there is the largest increase in display discomfort for the general population in history. It sounds like you have been bothered by all monitors back to CRT tubes, makes sense because they had visible flicker.


    The only way we could really get anywhere with this topic would be by putting several of us in the same room to test several monitors. We need to know if your setting's work for someone like me or others here, so far what I have been able to test has failed, flicker free or not. I could be doing something wrong with the settings or adjustments though, we do not have a controlled experiment is my point.  


    As for the yellow glasses or filters I think we might be missing some science there to explain exactly what they are doing to the blue light, I will post about this after speaking with the light doctor. My question will be about how they filter blue light and do they filter the entire wavelength of blue 100%. I'm not satisfied yet with the claims made here that they filter 100% of all blue light out, I want to know more about how this works than the claims.


    Anyway, all of this discussion is helpful. I appreciate everyone's view's because we all have important thing's to add regardless of whether or not we are all suffering for the same reason.



  • tfouto Level 1 Level 1



    As i told you before i have the same monitor than you. Samsung SA850. I cant use it at full brightness. Only with brightness at 25% and flux installed. No problem using at 25% with PWM for me...

  • mojarvinen Level 1 Level 1

    tfouto - sorry I didn't remember that you had said that. It's very interesting that you can deal with the worst offender for me.


    I don't deny that you have the problem, but just as a thought, could it be that the light intensity at 25 % is so low that the flicker does not affect anymore. I mean, it's probably a contrast between black and bright and when it's 25 % the difference between black and bright is so low that the eye does not percieve it as flicker anymore.


    I have the exact same display sitting next to this one now, so I could try that out. It's just that it takes sometimes hours to be sure, so it's not very scientific. I might be able to look at it for 2 hours, but I do not want to test it for a couple of days, because then my eyes would be fried if it happens that it still irritates. Though, a monitor should not be usable only at 25% brighness.


    Anyway, I urge those of you that have the financial capability to try the HP display. If it does not work, return or sell it. For me it's perfect, after 20+ years of testing different displays.

  • tfouto Level 1 Level 1

    mojarvinen, at the ambience of light in my room 25% is great enough. 100% is way, to bright.


    25% means that 25 of the time the light is at full brightness. So the contrast is really big, altought the samsung dont have sharp pwm, it's more curved, not so agressive...

  • tfouto Level 1 Level 1

    Interesting read:




    Quantum Dots are going to revolutionize and reenergize LCDs for the next 5+ years.

  • Jessiah1 Level 1 Level 1

    tfouto, have you tried the Sony Vaio or another quantum display yet? I tried the Sony Vaio and no luck, the wavelength graph you posted comparing a Quantum dot display and a regular LED display show something interesting. Do you notice how the peak blue wavelength is the same and they gave away some yellow and red to get higher yellow and red in other places? Sure it is great to add in stronger wavelengths through the spectrum however I suspect they cannot "hide" the blue spike from our eye's without significant raises to the yellow and red spectrum.


    Something you can notice from the graph below is how sunlight has the most blue light of all light sources, however it also has the most yellow, green and red as well. Perhaps one day this can be mimicked by LED light's with quantum dots, we can hope. I believe but cannot articulate with science:  Sunlight coming from a distance and traveling through our atmosphere is highly conditioned to the point where any disturbance in the delivery of the light source is almost undetectable. We also see WITH sunlight and we do not look directly at it where with lap tops and displays we technically are looking directly at the light for long periods. In addition to this the light source is very close and any disturbance in it's delivery would be hard to filter out, PWM, dithering and power supply fluctuations for example which due to the reactive nature of LED are intensified. When you have spikes in blue, the color our eyes are most sensitive to, any disturbances will be more offensive. CFL lights for example are almost as bad for me as LED. I would say if you are not sensitive to CFL blue spectrum may not be as much of an issue for you, maybe a good measurement of spectrum Vs. flicker for some here? Just food for thought:)









  • peter_watt Level 3 Level 3

    tfouto wrote:




    It's totally diferent, the spectrum of light of a clear sky and a led screen.


    Clear light it's a flat spectrum. All the cones of the eye are receiving the same amounts of light. The processing of color in the brain is even.


    On a led screen, the light is basically almost blue part of the spectrum at a high energy. The green and red are much lower. The blue cones are the most stimulated. And the problem is that the eye has much less blue cones than green or red. Much, much less. I suppose the blue cones are much more sensitive, or the brain processing the blue is more efective. Maybe the processing of light in brain with such an uneven spectrum of light is problematic for some.


    The problem is just not the blue light, it's the totally uneven distribution of light. That's the difference between a clear light and a LED screen. It's the relationship between the amount of total light received by all cones and the blue ones... A world of difference...



    Blue light is blue light, The blue on your screen is the same as the blue in the sky.


    White LED light which you describe as:-

    "almost blue part of the spectrum at a high energy. The green and red are much lower"

    would not be white, it would be a blue(ish).


    Unever distribution of light frequencies is called colour.


    Don't understand your science.

  • Petmyfurlistentomepurr Level 1 Level 1

    I just wanna say thanks to everyone who posts Information In here. I check this everyday to see If I can learn something new. When It comes to using my computer It seems the only relief from flickering I can get

    Is when It's hooked up to my plasma tv. Is that because of the 600hz? I'm not really sure myself but I don't notice any flickering Issues when using It. I use a Samsung plamsma that I paid 399 for 3 years ago. I was wondering If I bought a new plasma T.V.  would I be able to use that one with no Issues? I'm just wondering have they changed the technology In the Plasma T.V.'s? Are they loaded up with fluorescent and LED bulbs?

  • Jessiah1 Level 1 Level 1

    I currently use a Pioneer Kuro Plasma monitor for computer use, it is 7 year old tech. at this point. Part of why a plasma works has to do with the millions of individual noble gas cells containing the three primary colors of red, blue and green. Phosphor coatings are also used to make accurate color behind the gas cells. The technology is difficult to explain but the gasses work similar to fluorescent lighting by reacting to electricity to create light. Plasma's provide a very accurate color spectrum however they use much more energy for the same reason an incandescent light bulb does, higher heat to work.


    In my personal experience something has been done to newer plasma monitors that has made them much worse for me to view than my 7 year old Pioneer which is the only monitor I have left I can use comfortably. So I would say you are at risk trying the newer Plasma's however often places like best buy accept them as returns within 15 days for a full refund so no harm in trying them out. I would try Panasonic or Pioneer if you can find one that is affordable, I do not think they make anything lower priced any longer....Were talking $5000 plus for Pioneer elite models if those are even still available.


    Hope this is helpful,