Screen parts hypothesis

There are very limited evidence that the following parts may create symptoms that are unrelated to flicker:

  • front polarizer
  • LCD matrix itself, presumably glass substrate with transistors
  • BEF and similar brightness enhancing layers for a backlight
    .

1. chahahc's post

Here is chahahc's post where he removed BEF or another brightness enhancement layer in five monitors and in every time it greatly reduced symptoms. But not totally. He also wrote this: 'I've removed antiglare coatings, removed entire front polarizer films, removed/ rearranged the various plastic panel diffusers, ccfl backlights, led backlights, janky diy incandescent backlights(which was actually pretty nice)'

2. infromerkh's story

I've met infromerkh at a huge Russian-speaking tech forum and he told me about his experience with screen layers.
I am translating it below.

For a very long time, I had an old safe 17 "LG monitor (LG L1717s, TN) and I didn't know LCD screens can bring me troubles. Then I broke it in 2017. By 'broke' I mean it became partially broken, I can turn it on. When I realized other screens hurt my eyes, I tried to purchase other monitors, not like mine, but also 17", and rearranged the LCD panels within them. I thought it might have something to do with the electronics of the monitor. When I realized that the electronics did not affect, I began to disassemble the panels, and I did not find any differences except for the BEF (which I did not have and in others it was most often). If I found BEF, I took it out right away.
Then I thought it was the front polarizer, but it can't be easily peeled off. Therefore, I simply rearranged only the matrix glasses with both polarizers from my reference (normal) monitor to others, and my sensations moved steadily with it. At first, I tried it with monitors from other companies, then with LG, but other models.
Then I got tired of all this and I just bought the same one as mine.
You can't imagine my level of disappointment.
It also turned out to be unsafe.
By swapping the glasses with polarizers in places, I was again convinced of the stability of the results. The next monitors, the same as my LG, I disassembled only to remove the BEF, there was no point in rearranging glasses. The matrix models differed by one letter at the end and the sensations were also different, somewhere there was a strongly pronounced 'directed lamp effect', somewhere there was a pain in the eyes and fake clarity, somewhere both.
I purchased this LG 5 times and all 5 screens turned to be bad. They all trigger my symptoms and my old LG doesn't. I still have my old LG, now it has lines running all across the screen, but you can look at it, just not for a long time, otherwise your eyes will hurt (differently). It later turned out that more than 20 LCD panel modifications for this monitor were produced simultaneously, and this is only by LG, while often monitors have a panel from a completely different manufacturer.

Eventually, I tried to rearrange polarizers. After stripping off the polarizers, the image looks bleached and scratched. I glued them back with scotch tape, but the quality of the image is not the same. But even like this, my old LG is different from everything else that I had. I really didn’t want to rip off the polarizers, but I was sure that the reason was in them and I would just move them to any other glass and the problem was solved (or at least the reason was found). But it turned out to be only 40% solved. The remaining 60% is the glass itself.
Tried a bad polarizer on a good monitor. It became bad, there was a pain in the eyes. The polarizer also plays a big role. But at least they can be replaced.
I also found a patent for 'improved polarizer' - here is translated post and my original post in Russian
Some advice:

  • a good polarizer on top of the "bad" changes almost nothing (checked), it is necessary to remove the old one
  • the polarizer is removed very reluctantly, the risk of breaking the matrix is large, it is better to check on a screen that you don't mind breaking.

Finally, I decided to break one of those bad matrices (also TN) and see what's inside. Matrix can't be fixed after this, it destroys it. So I broke the glass block, got two glasses and removed liquid crystals that were between them.
I found out that a lower glass substrate with transistors (it is not entirely clear as it some mirror-like effect) is troublesome.
I placed this lower glass on the window and looked at the street through it, the symptoms did not take long to appear. Even while I was removing the lower polarizer, my eyes suddenly hurt, I thought why? Then I realized that the table lamp was reflected from the matrix and the light, being 'bad', got in the eyes.
I also did this. The table lamp is directed to the ceiling, on top of it lies the bottom glass from the matrix. In a dark room, I lie on the couch and listen to music looking at the ceiling. The brightness in the room is low. After a couple of minutes, the eyes sensed something wrong, and after 10 minutes they asked to stop the experiment. Even when looking away, peripheral vision still catches this unpleasant light.
Later on, I tested BEF, similarly placing it above the table lamp, and found out that it also turns light into uncomfortable light. I have no idea why.
I also tested different barriers between me and the screen. It became slightly better, but not significantly with some films (20%), with silicone (25%), with a thin aquarium (0.5 cm) filled with oil (30-40%), but the aquarium should be kept close to the eyes and not to the screen.

I will proofread these posts later; now about my experience. I didn't find any connection of my symptoms to any sort of flicker or software (at least yet, but I've done a plethora of tests).
I tried to disassemble a bunch of smartphone screens, but I found only the cheapest screens for this and they can be easier for the eyes than middle-range or upper-range screens, so I'm looking for new screens to try right now.
I disassembled Samsung a12 that is way easier for me than better smartphones but still seems to be symptomatic enough for the experiment, and got weird results looking through a combination of a lower glass substrate with transistors +lower polarizer (they are glued together) and layer that I could not identify, it is not BEF but is similar to BEF.

infromerkh's experiments are interesting. I'm not sure if infromerkh is saying he found another bef layer sandwiched between the the two glass panes of the lcd panel. I think you may be onto something with the BEF layers. As just holding them and staring at them long enough started giving me some symptoms. And also all the lcd screens I've taken apart had what I assume to be a BEF reflective layer applied to the bottom of the rear polarizer as it had a similar semi reflective look to the discrete BEF layers that I removed from the screen. I wonder if there's a way to remove that layer. I wonder if sanding it off with some steel wool or sandpaper might do the trick, turning it from a BEFRP layer into a diffuser/polarizer layer.

    chahahc Hello chahahc! Thank you for joining!
    There are no other layers in between glass panels aside from liquid crystals, and there could not be; BEF is used solely after the rear polarizer. But symptoms from BEF and symptoms from this glass layer are weirdly similar for infromerkh. I found a video where a laser ray goes through BEF and comes out not as a dot, but as a line. Infromerkh immediately checked BEF - it makes a line. And he checked the glass layer. Glass layer makes a cross. Here is a photo. It is hard to explain. Random material won't scatter the laser ray like this, we tried. It will make a dot or a scattered dot or a big scattered circle. Now all the screen layers bend laser ray in interesting ways. I did not have big troubles with BEF (and also my sensitivity seems to be much smaller than infromerkh's) but another BEF-like layer made me uncomfortable. That one makes a thick line instead of a thin line, and it also reflects polarized light back (that could be BEFRP or something else).

    Stricty speaking, BEF was uncomfortable to look through, cause it has a strange optical effect. But it gave little troubles when I applied it above the normal screen out of curiosity. BEFRP, on the other hand, managed to be problematic all the time, including when it reflected light, or when I applied it above the normal screen. It has the same optical effect but less light gets through it.

    So you say that there is another layer within the screen that you left within the screen? That could be exactly what I just described, as that BEFRP or a similar one was attached to the rear polarizer. I disassembled a screen that was not working and will never be after what I've done, so no way to say if the removal is safe. But I felt like it is not entirely glued, there's a chance it can be removed with no consequences.

    Infromerkh had no reflective polarizers applied to rear polarizer among the screens he disassembled (or at least I understood so). I disassembled 6 IPS smartphone screens and all of them had something attached to the rear polarizer, looking different every time.

    I do feel that we are onto something.

    I also wanted to ask you about the thread where you posted about the matrix. What exactly was the state of the matrix when you made the video? With or without polarizers? infromerkh says that pixel array should be visible on camera, especially without polarizers.
    As I now have a big suspicion about the very matrix, I need all the possible clues. Also I got all these symptoms on Amoleds (and I am entirely not PWM-sensitive), with a visual effect of 'directed lamp', so there's a chance they share something that IPS matrix can have (as they do not have BEF layers or any other backlight layers).
    I thought this 'directed lamp effect' will move together with BEF, but infromerkh says it moves with the matrix.

        Found more posts (old) about screen parts: @eyestrainsolutions replaced the entire screen of iPhone 5, then the glass with a front polarizing film of iPad 4, and finally the entire screen of iPhone 6, all times it helped entirely. Those posts are old, since then it seems that the option to replace the screen for a cheap Chinese one disappeared: cheap screens from AliExpress now can also trigger symptoms. I already encountered one case when a person repaired a safe phone, changed the screen for a non-original one, and got eyestrain as a result (Post in Russian).
        I am not entirely sure what was that polarizing film, as LCD front glass theoretically should not have any polarizing films attached...

        Oh, forgot to mention. Before infromerkh told me it makes no sense to apply another polarizer on top of the front one, I purchased a few and tried it myself. Got little to no success. (And I suspect that by applying a privacy film I even managed to make things subtly worse. Privacy film works as polarizer with specific qualities)

        Mrak0020

        I just was unsure if infromerkh was saying that he found a BEF lay or something similar sandwiched between the two panes of glass that compose the lcd panel itself rather than attached to the outer surfaces. The rear lcd panel polarizer on my monitor (closest to the backlight) that has the reflective film on it is I'm assuming a BEFRP layer, probably similar to the reflective coatings you've found on the screens you've disassembled. Which is probably why I still got symptoms even though I removed the front antiglare film, the discrete BEF layer, and changed the backlight to an incandescent light to minimize blue light issues and to make it so that the setup was something of a combined backlight/bias light/minimized flicker., and eventually just removed the front polarizer altogether and used my maui jim polarized sunglasses as the "polarizer" lol (which surprisingly helped a bit).

        The video was of my second HP22es that has just the front antiglare film removed and the discrete BEF/diffuser layers removed. So yeah I assume it must be the rear polarizer/BEFRP layer causing this shimmering/dithering pattern.

        (before I broke the first HP22es monitor) I did peel back both the front and rear polarizer films in one corner to reveal just the bare lcd panel and It did look more or less like a pane of glass. Which is kind of expected as LCD screens should just look like stained glass windows, because that's basically what they are. But they don't.

        Now I wonder. So the bare lcd panel probably has the lowest chance of causing symptoms. So maybe applying a polarizer film from the auto store onto a pane of glass and using that as the rear polarizer, then using polarized sunglasses like my maui jims as the front polarizer and just using a bare lcd panel….I wonder how that would work. But unfortunately I'm not in the situation to do that kind of experimentation currently.

        It also seems that that pixel density is only kind of relevant to my symptoms. In that it isn't the pixel density itself, but its relationship to how much odd effects it causes like dithering or shimmering. Low pixel density on projectors don't seem to bother me as long as the pixels are very clear and not blurry.

            chahahc
            Thank you for the explanation about the video!

            chahahc So the bare lcd panel probably has the lowest chance of causing symptoms

            Based on infromerkh's results, the bare LCD panel is capable of creating 60% of the symptoms; but thinking about it, infromerkh had no reflective layers attached to the rear polarizer.
            If you ever decide to peel off the rear polarizer with BEFRP, I would advise starting gradually, removing the BEFRP only, and seeing what happens.

                  13 days later

                  Mrak0020 So just the bare LCD panel with everything removed from it still caused symptoms just looking through it?

                      4 months later

                      Did you think about LEDs in backlit? I think, that many problems can come from sources of light, not only from light processing layers. I have similar problems, but I can see these symptoms /especially bad recognizing iluminated object and orientation between them in space/ undel LED light sources of interiors /exterieror also - street lights/. Many LCD IPS screens make me confused, not able to think about informations on screen, if you can understand me. Not recognizing of information - unreadibility of screen /images, texts, slow understanding of content/ really reming me ,,reflected lamp" , when I am looking at TV and my girlfriend have reading a book, when lamp is partially mirrored into surface of TV.

                      Is necessary to say, that I have problem with AMOLED /for example/ only with any pixel density /FHD, FHD+ on 6 inch screen/ a must be under this f*cking covering hard glass /this beautiful chromatic abberation make s me sick/. Actually I am using Galaxy Note 9 with density about 519PPI and theres no any problem /after few hours of compilating emails and other stuff some problems are observable/.

                        8 days later

                        Mrak0020

                        An update on some things. I tried fiddling with my other HP 22es monitor (had two, broke one in experimenting). These types of budget monitors are actually really convenient to mess with as it's not like higher end monitors where there is a separate lcd panel assembly housed within an exterior shell. Instead the lcd panel assembly is basically the entire monitor itself as shown in image 1 and image 2. So you can just pop the tabs around the monitor and open it up like a manila file folder and pull all the various film layers out.

                        I had already long since removed all the flexible plastic film layers so the only layers left were the thick rigid plastic spacer/diffuser panel and the rearmost white reflective layer. I tried taking out the rigid plastic spacer panel and interestingly it has a very fine frenel lens molded into one side of it. Image 3 and image 4 show how this frenel effect looks very similar to the various other flexible BEF layers. Image 5 shows the diffusion pattern printed onto other side of the rigid panel.

                        This piqued my interest a bit since I don't remember any rigid panels from the other monitors I disassembled having frenel lenses. I double checked and they indeed didn't. BUT they did all have different diffusion patterns, shown in image 6, image 7, and image 8 (those monitors have long since been destroyed and the plastic panels are now used in the garden, hence why they're dirty). And the diffusion pattern on image 8 was actually thousands of little dome shaped circular lenses molded into the panel, not just a typical printed white pattern. Not sure whether or not if that technically counts as a frenel lens.

                        So I tried using the monitor with nothing but the rear most white reflective layer. And the basket weaving dithering pattern (that I posted about here) is now gone. So I can say almost certainly that it was caused by the frenel lens on the rigid plastic panel interacting with the LCD panel that caused it. It now looks somewhat like an illuminated stained glass window. But just like in infromerkhs experience, the LCD panel itself still has this odd shimmering quality that is similar to the BEF and frenel layers. Though it is still far better on my eyes than with any of the various layers installed. I tried to capture the effect in image 9 and image 10. Image 10 is worse that what it looks like in person but it does display the effect that I'm describing.

                        Now the reflective layer that is attached directly to the LCD panel (as described in the previous posts) looks like it may require some risky operations to remove, operations that may end up destroying the LCD panel and rendering the monitor useless. So for now I'm just going to remove the rear white reflective layer (since it's too floppy and unstable, and a little grainy looking) and then spray paint the entire inner rear side white in it's place. Then I'll use the monitor in that configuration to see how it works. And I'll decide how to proceed from there.

                        OyoLarsen

                        I also get those symptoms. Like when your brain is really buzzed after looking at a monitor for a while and you're trying to look at things, and it's like you can see, but you can't see. Like the vision is there but your brain is no longer understanding the visual information you're receiving. "Brainfog" and "eyestrain" are woefully inadequate terms to describe the experience.

                              chahahc Its ,,unreadible". Remind me looking at cubistic oilpainting. Some details are senseful, but I don't quite understand the whole information.

                              Try to set refresh rate to 60Hz.

                                13 days later

                                So I went a little different of a route than what I originally planned by trying to make an experimental reflective lcd display. Instead of spray painting inner rear side of the monitor I completely removed the front polarizer layer and disconnected the backlight. In place of the front polarizer I use my maui jim polarized sunglasses. The removal of the front polarizer layer has made the monitor somewhat bright enough to play with as a reflective lcd monitor. Though it is probably 10% or so of the brightness of the Sun Vision Display rlcd monitor.

                                An interesting thing is that I get noticeably more eyestrain when looking at the monitor in portrait than when it normal landscape orientation. I'm not exactly sure why this is but I'm thinking that the way the LCD subpixel matrix is laid out probably has something to do with it. I try using it for some time to see what it's like.

                                You can see here the monitor and how the adhesive is still not fully removed. https://imgur.com/IWWZ5DM

                                This is a picture when looking at the monitor through the polarized sunglasses. https://imgur.com/zIynpwp

                                Here's a lux meter reading. It's a 10x reading so around 10,000 lux. It seems it needs at least around 5,000 lux for it to be usable. https://imgur.com/VXl8lGf

                                Here's a portrait orientation of the monitor while looking through the polarized sunglasses with around 3300lux illumination. https://imgur.com/EIUGABM

                                Note, it was an absolute bear to get the adhesive off and I still haven't fully gotten it all off but it's good enough for my experimentation purposes. I had to use some kleen strip stripping compound for the heavy lifting. 91% isopropyl alcohol was marginal and only used to get the last bit off and make the glass clear.

                                3 years later
                                dev