The Dirty Screen Effect
“The Dirty Screen” effect is when the complex layers and lighting of the LCD is uneven, and that non-uniformity is visible in the backlight we see looking at the screen. In this specific case, a dark horizontal bar across the screen is highly distracting when viewing content. This effect is most noticeable when scrolling through Google, or scrolling across vertical lines on a white background. This effect can show in many different forms, and can happen at any time to your 15″ M2 MacBook Pro, in this guide we will show you examples and solutions to this issue.
Looking at the X-Ray iFixit has provided, we can see a padding element that Apple is using to protect the screen from flexing and damage is the culprit for this bar we are seeing. This foam padding piece is blocking, therefore compromising, the uniformity of the backlight resulting in the as before mentioned “dirty screen” effect.
Why is this happening now and not on previous models?
On previous generation MacBooks Apple used a larger, wider rectangle shaped foam pad that covered the entire surface area and evenly dispersed the backlighting, versus the new bar with two 90 degree uprights on the new MBA 15″ that leaves us with the dirty bar across the screen. This is likely a cost saving factor for Apple, although the exact reason as to why the switch was made is still not known to the public. We hope Apple will return to the old foam pad design, as this would immediately resolve the issues as well as prevent future ones.
You can try applying minimal pressure to the visibly dark spots, using a clean microfiber cloth, that may solve the issue for a small amount of time. The heat of the LCD and other factors will result in the bar coming back again and again, so this DIY fix is only a temporary bandage. Replacing the LCD is the only sure fire fix for this issue. Until Apple changes the design back, returning if you are in return policy or replacing the LCD, is the only option for those unfortunate to be stuck with the dirty screen effect.