Gurm I tested an iPhone 7 last night with polarised sunnies. The polarisation method is indeed very different to the 6s. I'm still a little skeptical seeing as I feel like it's something to do with the software as well as the screen, but perhaps I'll take the plunge and buy a second hand 7 or 7+ to confirm. And failing that, a HTC M9. And failing that, a Lumia 950. Then I'll be up to 10 phones! We need a phone swap system on this forum aha!

ryans Which is a little strange given that Samsung PWM is usually pretty bad and it's running the same OS as many other problem phones. A mystery indeed.

Sunspark Please give us your full testing impressions when you can. Any chance you could check the polarisation characteristics with a pair of sunnies?

        Sorry guys, it was a bust. There is display variation with this panel, and I just happened to get one with a 9000K+ colour temperature that also had a slight green tint which I associate with Samsung. I was procrastinating because other than being tired I had a suspicion it would be like this.

        I will write some observations though..

        Device came with Nougat, which combined with the colour temperature was uncomfortable right off the bat. I immediately sideloaded Android P. sRGB mode in the developer options does not work, you need to install a different kernel or install Lineage, which I am not going to bother doing since I know the native temperature is way high.

        Android P was a bit more comfortable than Nougat. Google has spent a lot of time working on it, nice interface. Also a brightness bug in P on this device where if you adjust it lower than 80% it goes really dim really fast.

        Phone did not come with a USB-A to C cable.. C to C only. Fortunately I had a Sony cable that was A-to-C here that I found on the ground along with the charger. 🙂 New cable worked just fine.

        USB drivers on Win 7 were a real hassle, after downloading Google's usb driver, I still needed to install it twice.. once in 'normal mode' connected to the computer, and a second time on the computer when it was in recovery mode.

        No need to bootloader unlock this (which is a toggle option), usb debugging mode alone is fine. All you do is adb sideload the zip file.

        I didn't bother peeling off the plastic, though I did peel it off a little so I could look at it with and without. Did not make a difference, other than clarity.

        Phone is noticably brighter when my M8 is placed next to it and my M8 appears to have a reddish hue when sitting next to it (which you do not see when it is by itself).

        The last LCD display panel that I saw on a new device that seemed ok was a store demo model of the G7. This panel is not an RGB panel, but an RGBW one which is interesting. I'm too cheap to get it right now, but I will take a look at it again at a different store.

        I don't have sunglasses on hand.. there is one in the basement somewhere but I don't want to go through boxes looking for it. Though I am curious to dig it out sometime.

        So yeah, would not recommend the Essential to this crowd.

          AGI You can compare by typing chrome://gpu/ on the address bar, before and after if you ever felt like it. You can also flip some switches with chrome://flags/ as well.

          • AGI replied to this.

              Hi all,

              I’ve read thru most of the comments/ replies on this page;

              Firstly I’m glad I’m not the only one with this LED screen issue! Like someone else put, I don’t know how people can look at LED screens all day!!

              Secondly I’m surprised I haven’t come across this forum/ website before, every couple of months I search the internet hoping someone has found a “magic” cure for LED related headaches or an entirely new backlighting technology.

              I know exactly the symptoms people are describing, when viewing a LED screen within 5/10 mins I get a banging headache. On a couple of occasions I’ve forced myself to watch an LED screen for around 45mins (to get used to it!? Recommended by friends) and ended up feeling sick with a headache and having to go into a dark room, this would last two or three days.

              My doctor and optician both were unsure and recommended a visual stress test which proved it wasn’t visual stress.

              From my investigation and experiences with LED screens;

              Refresh rates;

              I know CCFL and LED refresh differently, however I can view a CCFL backlit screen any brightness any refresh rate fine. With LED no matter what brightness or refresh rate even night shift mode (reducing blue light on the newer I-pads) gives me a banging headache.

              I’m using a Samsung galaxy S3 with android 4.3 which I know is LED backlit but I’m fine with it (which is weird), however as a test I took the phone apart and put my screen on a S3 with android 4.4.4 I could feel straight away that it was giving me a headache. This makes me think that something changed in the software. However I have also found that any of the newer LED screens (after 2012ish) in laptops, telly’s, phones and even cars multimedia screens give me headaches which makes me think something changed in the LED technology.

              I think the resolution of the screens plays apart too, with HD and UHD having very fine detail and vivid colours, which certain people are sensitive to??

              I’ve read about LED screens kinda tricking us into thinking the blue light is other colours (somehow). Night shift on I-pads (as mentioned above) reduces blue light but doesn’t help with the headaches!

              So far my conclusion; it’s probably a mixture of a few different things.

              By wearing polarising or tinted sunglasses this delays the headache by 5/10mins and the same is for privacy screens and filters.

              I wanted to share this so other people have the info and can maybe avoid headaches etc.

              Can anyone recommend anything else to try?? Because LEDs are everywhere and my S3 and HP CCFL backlit laptop are starting to feel the strain of modern apps, software, etc.

              Maybe we need to start a petition or something for Samsung, HP, Apple, etc. to bring back CCFL screen options or look into new tech?

              Sorry for any spelling or grammar errors; I’ve composed this on an old I-pad over a few evenings (very frustrating).

              • KM replied to this.

                Sunspark You can compare by typing chrome://gpu/ on the address bar, before and after if you ever felt like it. You can also flip some switches with chrome://flags/ as well.

                Hey, thanks. This sounds powerful but I am not sure which use to make of all that information, e.g., what are "Problems Detected"? Does the list refer to my specific device or the version of Chrome installed?

                  6 days later

                  Seanicus @Sunspark Try updating Essential Phone to Android 9 (recently released). Not sure if they fixed anything; worth trying.

                      My iPhone 6S has been on stock OS since I bought it (iOS 10.3.x) and has been 'good'.

                      However I foolishly upgraded to the latest iOS11, and while it actually runs quicker than iOS10, something has clearly changed with the software/drivers as it is unusable after <10 minutes, with symptoms similar to temporal dithering, (swelling feeling in the lower eye muscles, pupils dilated).

                      • KM likes this.

                      ryans I just received one of these (Essential Phone) today, and found pwm at all levels using the photodiode and oscilloscope, on the original firmware. (thanks to the circuit and post from @Wootever https://ledstrain.org/d/312-homemade-oscilloscope-to-detect-pwm-diy-guide/19 )
                      Updated to 8.1.0, then 9.0 and looks like the PWM still there. Its a weird looking waveform guessing around 180Hz, with 5-10kHz modulation within it. Adjusting the brightness just changes the gross amplitude)

                      I am presently using an LG v30+ which appears to be one of the few modulated screens that does not give me headaches, however I need to keep it above 42% brightness. I am not sure why, but the waveform on the scope 42-100% looks very different 0-41% so maybe something is in there to explain.
                      My previous phone was an LG G5 which did not show any pwm above 37% brightness.

                      Just a heads up though, I haven't used an oscilloscope/done engineering stuff in a long time, so this could all be something entirely different.
                      I don't know why the embedded image of the oscilloscope doesn't show - its at (remove spaces) https://imgur.com/ a/08FyTDR

                      https://imgur.com/a/08FyTDR

                          12 days later

                          Thanks for sharing. My old Galaxy S5 is not running well. I am afraid I might have to suck it up and buy a phone I know will give me headaches/strain in hopes that my eyes will adjust.

                          • KM replied to this.

                            Jimmyww I’m using a Samsung galaxy S3 with android 4.3 which I know is LED backlit but I’m fine with it (which is weird), however as a test I took the phone apart and put my screen on a S3 with android 4.4.4 I could feel straight away that it was giving me a headache. This makes me think that something changed in the software.

                            The Galaxy S3 seems to have an AMOLED display which flickers at 240 Hz PWM frequency. Because you can look at it that probably means you do not have a problem with AMOLED and that 240 Hz flicker in particular.
                            Eye strain that one may have after upgrading any OS has been confirmed by many people now. Unlike PWM, the reasons for this are still unknown and are astonishingly hard to capture.

                            On the other hand, this means people could turn a device they previously thought to be totally unusable into a usable device by choosing the right ROM/OS.
                            There are at least two factors at play: The display hardware and the software driving it. Making it tricky to find a working combination.

                            Jimmyww I think the resolution of the screens plays apart too, with HD and UHD having very fine detail and vivid colours, which certain people are sensitive to??

                            If you find a high resolution display that you can use, you can eliminate that theory. After all, the 720x1280 4.8" display you can use has ~306 PPI, so is pretty high-res already.

                            It would be interesting to know if you can use a current custom ROM like LineageOS on a Galaxy S3. May help a little to extend its life (providing the unlocking procedure succeeds). Or it may introduce eye strain...

                                  KM Eye strain that one may have after upgrading any OS has been confirmed by many people now.

                                  I confirm that with Android. Factory-reset helped.

                                  • KM likes this.

                                    olgomar What does the LG's wave look like before and after the threshold? The more data we have, the better.

                                    I have been interested in buying a Rigol oscilloscope, but I am unsure if the display flickers or is otherwise uncomfortable. Could you measure the display if you have the time? It seems no one has ever done this before. They seem to use a very special form of LCD that differs from standard ones.

                                    Since you use the OPT101 circuit, did you find it can capture even high frequencies? I was concerned of its low bandwidth specs that say like "14 kHz".

                                        ryans Before throwing the phone away, you might want to try to unlock it and install a custom ROM. Those may make the device more responsible. By doing do you could also provide info about which ROMs are eye-friendly on the S5.

                                          KM Could you measure the display if you have the time? It seems no one has ever done this before. They seem to use a very special form of LCD that differs from standard ones.

                                          Since you use the OPT101 circuit, did you find it can capture even high frequencies? I was concerned of its low bandwidth specs that say like "14 kHz".
                                          Edit: I just re-read your post and saw you want a measurement of the Rigol, it is packed away again atm, so I will get on to that the next time I do some testing.
                                          KM What does the LG's wave look like before and after the threshold? The more data we have, the better.
                                          I have put up the LG G5 flicker measurement photos here:
                                          https://imgur.com/a/McR5oFm
                                          I do not know about higher frequencies with the OPT101 other than the tests I have done so far.

                                                olgomar I meant the LG v30, because you said while it flickers it has a different waveform that causes you no trouble. Would be interesting to analyze the difference. It might help understand the difference between "good" and "bad" flicker.

                                                If you are interested in your OPT101 speed, you could test it for example with this Raspberry Pi LED circuit: https://ledstrain.org/d/375-howto-create-pwm-led-flicker-with-a-raspberry-pi/3

                                                    KM I meant the LG v30, because you said while it flickers it has a different waveform that causes you no trouble. Would be interesting to analyze the difference. It might help understand the difference between "good" and "bad" flicker.

                                                    Sure:
                                                    https://imgur.com/a/7gvXEvj

                                                        olgomar That is very interesting. The oscilloscope values are hard to see though. Was the input AC-coupled? Peak-to-peak voltage and frequency of the large spikes (50% brightness) the same as in the sine-like wave (38%)?
                                                        By the looks of it I would guess that at 50% the hardware switches from 240 Hz to 60 Hz like my OnePlus 3 does it at ~25%.
                                                        Like you I can not tolerate the 240 Hz but only the small 60 Hz pulsation.

                                                        But is it small on your device? The peak-to-peak and maximum voltages, which are hard to see in the photos are most interesting.

                                                            KM Was the input AC-coupled?

                                                            The input was DC coupled

                                                              KM I have been interested in buying a Rigol oscilloscope, but I am unsure if the display flickers or is otherwise uncomfortable. Could you measure the display if you have the time? It seems no one has ever done this before. They seem to use a very special form of LCD that differs from standard ones.

                                                              Here is the experiment result of the Rigol measuring itself. It looks like a higher frequency than the OPT101 will allow so not sure what to make of it.
                                                              https://imgur.com/a/eEXtcaF

                                                              • KM likes this.
                                                                dev