Black pixels in OLED screens light up when the brightness of iPhone 12 is very low

Experience it: display a completely black image on the screen of your iPhone 12, lower the brightness to 10% or 20% (or 0), then go to a darkened room. Wait a few moments for your eyes to get used to it: the smartphone screen may continue to glow in the dark, while on an OLED panel, the black pixels are supposed to be completely off regardless of the brightness of the screen. screen. So we should have a deep black, like explain it Sharp in our forums …

In this photo (taken in night mode) of iPhone 12 Pro plunged into black, we see that the screen supposed to be black is not really black.
This is not the case with this iPhone 11 Pro, whose OLED screen is plunged into the most complete darkness. In both cases, Arnaud used the application OLEDX.

This problem, illustrated by Arnaud above, is the subject of a long discussion on the Apple Support Forum, with supporting examples. The YouTube channel HDTVest released the colorimeter to precisely measure the luminance level of an iPhone 12 Pro screen: with a brightness reduced to 0, this level is 0.0003 nit whereas it should be 0, this which corresponds to an off pixel emitting no light.

When the iPhone’s brightness is at a normal level, a black pixel emits 0 nit, which is in line with normal things. With an LCD screen equipped with a traditional backlighting system, the blacks cannot be deep, there is always a light leak which should not exist with the OLED.

The uses of an iPhone brought back to a level of brightness such that you can not see much, under 20% say, are of several types, it can be useful at night to take a look at the time without waking up the whole bedroom for example, or to read or watch a movie next to your sleeping partner. This story is related to the yellow screens of iPhone 12 and 12 Pro which quickly appeared in the news after the launch of the devices.

About these more yellow screens, there are several possible explanations: it can be variations in the OLED specifications from one generation to the next, or it is Apple’s desire to offer less screens. blue. For those pixels that do not go out in low light, Apple may want to avoid the pangs of infinite contrast in the middle of the night …

On the other hand, we can rule out the hypothesis of chip binning, this industry standard practice of using components that do not have 100% efficiency on less high end devices, such as this is the case with M1 chips. All iPhone 12s are indeed affected (and we cannot really say that there is an “entry-level” model strictly speaking) by these black pixels which are not really. Many are hoping that a software update will solve this problem.


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