Have you ever checked out your cellphone and gotten a headache? Sometimes, it simply means you’ve got been on it too lengthy and have to take a break. For some people, nonetheless, it may imply you’ve got developed PWM flicker sensitivity as a result of method your cellphone’s show works.PWM, or pulse width modulation, is a technique of flickering a show to idiot the human eye into seeing a brighter or dimmer show. It’s a tactic utilized by most of the greatest telephones — together with the Apple iPhone, Google Pixel, Samsung Galaxy, and lots of others — for plenty of causes and has solely grow to be an increasing number of widespread as telephones proceed to change to OLED shows.The result’s a cellphone which may make you’re feeling nauseous, make your eyes damage, provide you with a headache, and even make you need to curl up in a ball for hours. So what’s PWM, why is it dangerous to some individuals, and what are you able to do about it? Other than getting a brand new PWM-friendly cellphone, we have got a number of options that may assist make your present cellphone somewhat extra eye-friendly.What is PWM dimming?(Image credit score: Nicholas Sutrich / Android Central)PWM dimming works by flashing the display screen on and off in a short time. Think of it a bit like watching a film, which is comprised of images being proven back-to-back many occasions per second.Your mind interprets this fast development of photographs as motion in a film, however within the case of PWM-dimmed telephones, your eyes see a brighter or dimmer picture relying on how typically your cellphone’s show is on or off per second.PWM dimming works by flashing the display screen on and off in a short time, which tips your eyes into seeing a “brighter” or “dimmer” display screen.The cause that is totally different from a film is that film frames are evenly lit in development from one to the following. PWM flashing, nonetheless, alternates between 100% brightness and 0% brightness, offering a harsh, stark distinction to your eyes and mind.(Image credit score: Nicholas Sutrich / Android Central)Graphs just like the one above — which present the Samsung Galaxy Z Fold 5’s outer show at 100% brightness — present the sample of on/off cycles that your eyes do not see however your mind perceives. The distinction between the best and lowest factors is the modulation, which is outlined as the proportion distinction between the brightest and dimmest values.Imagine a vibrant mild flashing continually at you in a darkish room and you may shortly perceive why that is problematic.In layman’s phrases, that merely means how vibrant the show will get for a break up second earlier than turning off momentarily, then repeating the cycle time and again a number of hundred occasions per second.(Image credit score: Nicholas Sutrich / Android Central)As you decrease the brightness slider, the display screen is not really getting dimmer. Instead, what’s occurring is that the display screen stays off for longer intervals of time because it continues to flash on and off tons of of occasions per second. Imagine a vibrant mild flashing at you continually in a darkish room, and you may shortly perceive why that is problematic.That distinction between the display screen being on for a break up second adopted by staying off for a break up second is extremely jarring to the human mind. While it would not have an effect on some individuals as negatively as others, it is nonetheless exposing you to a strobing mild all all through the day. We know from analysis that this sort of publicity is unhealthy on your well being.Why do telephones use PWM dimming?(Image credit score: Nicholas Sutrich / Android Central)Smartphone shows usually use two most important strategies to manage brightness. The commonest technique was what’s known as DC dimming, which controls the quantity of voltage despatched to an LED panel. The extra energy you provide, the brighter the LED will get. Reduce that energy, and the LED will get dimmer.But, as smartphones have begun to change to OLED shows an increasing number of typically, producers are utilizing PWM to handle brightness as an alternative of DC dimming. This sounds ridiculous — and, in lots of instances, it actually is — however there’s a legitimate cause for all of it.First, let’s shortly study the distinction between LCD panels and OLED shows. An LCD panel contains a totally white backlight behind coloured pixels. These coloured pixels act like a filter for the sunshine however don’t have anything to do with the brightness or depth of the sunshine itself. They are fully separate items of the show puzzle.This backlight could be dimmed individually from the coloured pixels by decreasing energy to the white LED backlight, thus, dimming that white mild like a light-weight bulb.(Image credit score: Valve)OLED shows use individually-lit pixels, sometimes made up of purple, inexperienced, and blue sub-pixels. Each of those sub-pixels provides off its personal mild, so the depth of the brightness is straight tied to the colour.As OLED pixels are dimmed, the accuracy and depth of the colour additionally dim. A couple of years in the past, OnePlus experimented with a completely DC-dimmed OLED panel on the OnePlus 6 and 6T. However, when the brightness dropped under 30% or so, greys would grow to be inexperienced, and different colours simply would not look proper.For this cause, producers like Samsung use PWM dimming. When a show makes use of PWM dimming, it is giving 100% energy to every pixel, guaranteeing that colour accuracy and depth keep the identical regardless of the brightness degree.It’s a superb resolution to a technological downside, but it surely forgets to take two main issues under consideration: human eyes and brains.Some producers, like Motorola, Xiaomi, and Nothing, have begun to supply hybrid options which can be far simpler on human eyes and brains, all whereas retaining the visible high quality we anticipate from OLED shows.Some producers are lastly realizing that strobing a light-weight at customers all day lengthy is not wholesome and are actually utilizing DC Dimming above 50% brightness.At larger brightness ranges on telephones just like the Motorola Edge Plus (2023), Nothing Phone (2), and Xiaomi 13, DC dimming controls the voltage degree of every particular person pixel. Each of those telephones makes use of DC dimming right down to a sure brightness degree — sometimes round 50% brightness — then switches to PWM dimming under that degree.This ensures that customers aren’t uncovered to the strobe mild flashing of a PWM show all day lengthy. Instead, this solely happens in decrease mild if the person needs to decrease the brightness degree.Waveforms and the mind(Image credit score: Nicholas Sutrich / Android Central)Dialing down additional into the causes of PWM/flicker-sensitivity, just a few elements appear to have an effect on most individuals on this class. When utilizing a device to measure flicker parameters, the tip end result comes out trying like a waveform on an oscilloscope. If I’ve already misplaced you, maintain tight. I promise I’ll preserve this straightforward.(Image credit score: Wikipedia)The most snug sample is the sine wave, which is represented by a clean curve that evenly strikes up and down at a gradual charge. Incandescent lightbulbs sport this sort of wave as a result of the filament inside by no means turns fully off through the traditional oscillating energy cycle that comes from energy traces. Displays that make the most of PWM dimming could be snug in the event that they adhere to the sine wave sample, however this comes with caveats.Displays that come throughout utilizing different waveform patterns above are inclined to flicker at various or harsher charges. I’ve discovered this to be extraordinarily uncomfortable generally. If you scroll again as much as the Fold 5 instance above, you may see it is utilizing a sq. waveform which is a really harsh on/off sample.Conversely, in the event you have a look at the sample of the Motorola Edge Plus (2023) within the picture under, you may see that it is a pretty flat waveform with very shallow dips at evenly-spaced intervals.(Image credit score: Nicholas Sutrich / Android Central)Lastly, I’ll have a look at the PWM charge, which implies how briskly the show can flicker per second. Most Samsung Galaxy and Google Pixel telephones flicker at a really low charge of 240Hz, or 240 occasions per second.Apple makes use of a frequency of 480Hz even if it makes use of related forms of OLED shows as Galaxy and Pixel telephones. Higher numbers can result in better consolation, even when utilizing PWM to “dim” a show, so iPhones are theoretically extra snug to take a look at than Galaxy or Pixel telephones.Higher (sooner) PWM charges can result in better consolation when utilizing a show that “dims” by utilizing pulse width modulation.But the telephones we suggest right here sometimes go properly past that in the event that they use PWM in any respect. The Honor 90, for instance, makes use of an especially excessive PWM charge of 3,840Hz. That’s 8x sooner than the iPhone and 16x sooner than most Galaxy or Pixel telephones. At this charge, even PWM flickering is probably going usable for most individuals.Other telephones on this listing, just like the Nothing Phone (2) and the Xiaomi 13, use a PWM charge of 1,920Hz when brightness will get decrease. Otherwise, at 50% brightness or above, these telephones make the most of DC dimming, an influence regulation technique that reduces the voltage to particular person LEDs within the show, making them basically flicker-free.How to take care of PWM sensitivity(Image credit score: Nicholas Sutrich / Android Central)Being delicate to flickering lights or shows is just no enjoyable. Flickering mild sources may cause eye straight, complications, dizziness, a way of vertigo, nausea, and loads of uncomfortable or painful sensations. Thankfully, there are methods of managing these signs and issues you are able to do to assist forestall them within the first place.No matter which cellphone you employ, being PWM or flicker-sensitive means it is best to take some precautions to make sure you’re not exposing your self to an excessive amount of flicker. Here are some ideas and tips to assist make your cellphone simpler on the eyes.See an optometristFirst and foremost, in the event you’re experiencing any of the signs described above whereas taking a look at your cellphone, go see an optometrist. I personally handled elevated sensitivity and harsher signs over a interval of some months earlier than I went to an optometrist, and I could not have been happier with my expertise.In my case, one eye had astigmatism, and my optometrist was capable of give me a brand new studying glasses prescription to appropriate for that astigmatism. Many people who find themselves delicate to flickering mild and flickering smartphone shows even have astigmatism, and correcting for this downside may very properly resolve your sensitivity challenge.In my case, I’m in a position to make use of flickering telephones as long as I put on my glasses, however even that is inside a restrict. I do not dare use any of those flickering telephones under 50% brightness or in a darkish room, and I usually can not use them when I’m not carrying my glasses.For me, which means I am unable to use my cellphone to navigate whereas driving since my glasses are for studying solely, and it implies that it is extremely inconvenient (or not possible) to take a look at flickering telephones for any size of time whereas doing bodily actions away from dwelling.Don’t use automated brightnessAutomatic brightness is a good idea when a cellphone makes use of DC dimming. For telephones that use PWM to dim, automated brightness is a fast technique to get a headache. Instead, handle the brightness your self and preserve it at a degree that you simply really feel is manageable and would not provide you with eye pressure.That’s as a result of PWM-dimmed telephones flicker extra harshly at decrease brightness ranges, growing the potential for PWM illness.I like to recommend utilizing this apply at the side of the following tip.Try a screen-dimming appDon’t use your cellphone’s brightness slider to regulate brightness. Instead, I might suggest protecting the system brightness slider at 100% to maintain display screen modulation as little as attainable. Then, use a screen-dimming app to manage brightness since it really works in another way.First off, I might by no means suggest dimming most smartphone shows below 50% in the event you’re delicate to mild flicker. Even many of the most eye-friendly smartphone shows begin to do humorous issues under 50% to be able to preserve excessive picture high quality at low brightness values.I’ve tried loads of screen-dimming apps, however this display screen and notification-dimming app is my all-time favourite. Not solely does it characteristic a helpful management panel that stays in your notification shade always and has a fast toggle button, but it surely really dims notifications and system-level dialogs.Many display screen dimming apps will solely dim apps by including a gray overlay on prime of the display screen which is not allowed to be displayed over system-level UI components. Worse but, most of those apps do not allow you to click on “secure” buttons which implies you recurrently must disable them simply to do regular issues in your cellphone.The app I really helpful has none of those issues and works as you’ll anticipate it to.Don’t use your cellphone in a darkish roomUsing your cellphone in a darkish room is without doubt one of the quickest methods to develop these terrible emotions of PWM illness. It would not matter what brightness degree your machine is at — particularly in the event you’re utilizing a cellphone that makes use of PWM to dim the show. Sitting in a darkish room taking a look at a vibrant cellphone simply is not good on your eyes.Instead, attempt to preserve the ambient lighting within the room at about the identical brightness degree as your cellphone. Automatic brightness would do that already, however for us PWM-sensitive people, automated brightness is not normally an choice since telephones are inclined to flicker extra at darker brightness ranges.Additionally, I might suggest utilizing a flicker meter to check the lightbulbs in your house to make sure they do not flicker. If you do not have a specialised mild meter, this flicker meter app is free and will help you detect mild bulb flicker.I would not use its measurements as a precise science, although. Rather, simply use it to assist detect bulbs that may be changed with flicker-free variations like these Sylvania flicker-free LED bulbs. I exploit these in my dwelling and love them.Don’t use darkish theme on some telephonesIt would possibly sound bizarre, however OLED shows utilizing PWM modulate extra when displaying darker colours. That’s as a result of colour and lightweight depth are linked collectively in a single LED diode, as I defined within the part method above. Phones utilizing OLED shows that use DC Dimming are simply effective to make use of darkish mode of any shade, as evidenced by the photographs under.Most darkish theme apps do not use a black background, which might really flip particular person OLED pixels fully off. Instead, many builders and smartphone corporations use a darkish gray background which is extra dangerous to your eyes than a totally black or fully white background.Image 1 of two(Image credit score: Nicholas Sutrich / Android Central)(Image credit score: Nicholas Sutrich / Android Central)Don’t consider me? Check out the photographs above, taken at a really gradual shutter velocity and excessive ISO to seize the PWM charge on every colour. The black bars you see working from the highest to the underside of the show are how the digicam sees the PWM charge. The thicker the bar, the extra modulation happens to create a colour.Notice that all the mild colours have a thinner black bar, and all of the darker colours have a a lot thicker bar? Those pixels must flicker much more to point out that darkish colour as a result of, when utilizing PWM, the brightness of a pixel is managed by the size of time the show is off through the pulsing cycle.Notice the greyscale picture, specifically, as these colours are the precise shades utilized in Android’s darkish theme throughout many producers and apps.Now, if we have a look at a cellphone that does correct DC dimming — the Motorola Edge Plus (2023) — you may see that each one colours are equally represented and have zero flicker distinction seen between them. That contains darker greyscale photographs.Image 1 of two(Image credit score: Nicholas Sutrich / Android Central)(Image credit score: Nicholas Sutrich / Android Central)On telephones that use PWM-dimmed OLED shows, use a light-weight theme in your cellphone’s UI after which cherry-pick apps which have settings for “lights out” mode. On apps like Twitter X, Lights Out mode makes the whole background black and solely illuminates the show when different colours or textual content are current. That ensures that much less of your show is awake to modulate on telephones that use PWM dimming.Lock the refresh chargeIt would possibly sound bizarre, however locking a cellphone’s show refresh charge is typically simpler on the eyes than a dynamic refresh charge on telephones that use PWM dimming. There are loads of theories as to why that is the case, however I personally suppose it is the variability of the refresh charge on LTPO OLED shows that is taking part in the largest half.Since the refresh charge adjustments continually on these shows relying on what app you are utilizing or what you are utilizing the cellphone for — however the PWM charge doubtless stays fixed — your eyes are continually bombarded with various ranges of unnatural show refresh patterns.Go into your cellphone’s show settings and discover the refresh charge choice. Sometimes that is known as “Smooth display” or one thing related. Either flip it off or choose a single refresh charge to check. Some telephones can help you choose from a number of totally different charges to lock the show at. My private eye-friendly favourite cellphone, the Motorola Edge Plus (2023), permits you to choose from 60Hz, 120Hz, or 165Hz.Depending on the show sort, selecting the bottom attainable refresh charge of 60Hz would possibly really be essentially the most snug. Give it a shot and see how you’re feeling!Get a greater cellphoneThe actuality is that our definition of “the best phones” typically revolves round processor speeds, digicam high quality, or different elements however typically neglects how unhealthy these telephones’ shows are for our eyes.Thankfully, the perfect telephones for PWM-sensitive individuals all supply nice experiences, processing speeds, high quality cameras, and, most significantly, shows that do not damage to take a look at.
Motorola Edge Plus (2023)
Motorola is again, child. Sporting a stunning design, an eye-friendly OLED show, a blazing-fast processor, and 2-day battery life, the Motorola Edge Plus (2023) is the perfect cellphone Motorola has made in years.