Apple goes for aesthetics, Samsung adds symmetry: Display Engineer explains why thin chins are bad: A recent brouhaha over the broken screen of a Pixel 3 XL has brought along the most illuminating explanation on why some manufacturers go with thick over thin chins in their phone designs. The Pixel 3 XL in question got a few permanent pink lines running from the bottom of the display which it allegedly received from a short foot-long drop.
The Reddit thread dedicated to the issue has turned into the oh-so-rare quality discussion on why screens are prone to do that after a self-proclaimed Apple phone display engineer entered the fray.
While he tipped the audience on some known facts – namely that OLED screens bend towards the bottom to fuse with the connector that drives their pixels. This fragile bond is extremely prone to having traces that run screen lines detach upon bottom impact with the ground, especially if the chin is thin. The pink lines that form are the result of said broken traces leaving pixels they command permanently on. The phenomenon even has a name in display engineer lingo – a VLD (vertical line defect).
Given that this 180-degree bottom bend is done on most OLED panels with plastic substrates like the ones most flagships are now using, everyone’s OLED models are prone to VLDs, especially if they have thinner “chins,” i.e. bottom bezels. When asked why isn’t every OLED phone made with thick chins then, the purported Apple display engineer dished out the following fascinating answer: