A number of Apple Watch Series 4 owners are reporting an unusual “light bleed” problem with their new devices.
Basically, when the display is dim enough, users report a relatively uneven brightness. According to anecdotal user reports, this manifests as the edges, corners or certain splotches of the display appearing much brighter than the interior.
While we can’t confirm that the issue affects every Apple Watch Series 4 model, it does appear to be fairly widespread.
The level of light bleed appears to vary between impacted users. Some users will only notice a small amount of uneven brightness around the edges, while other reports indicate more significant levels of light bleed.
It’s also worth noting that users report only noticing the issue when the display is at a low enough brightness, and only on certain Apple Watch faces or when using certain apps. Reportedly, it occurs in mostly dark but not black interfaces.
To be clear, OLED displays aren’t backlit, so the problem isn’t actually caused by light leakage. But most posts reporting the problem still call it a “light bleed.”
The cause of the issue isn’t readily clear, but one Redditor theorized that it could be tied to the fact that the Apple Watch Series 4’s OLED display doesn’t use pulse-width modulation (PMW) for brightness modulation.
Because of that, the Apple Watch Series 4’s display won’t flicker like most OLED-equipped smartphones. But it does apparently mean that users may notice uneven brightness when the display is dimly lit.
Other users suggest that it could be tied to gray uniformity issues that are common on many types of OLED displays.
There is, of course, an argument to be made whether this is a big deal or not. On impacted Apple Watch models, the problem isn’t noticeable except in pretty specific circumstances. And even on affected devices, it doesn’t negatively impact the usability of the Watch.
According to users reporting the problem on Reddit, Apple appears to be aware of the situation and is looking into it.