A Hidden Bar Code in iPhone Screens Saved Apple Hundreds of Millions of Dollars

Next time you try to wipe a smudge off your iPhone screen, take a closer look. See if you can spot one of the two tiny QR codes etched into its glass. Chances are you won’t be able to find them. Both codes are tiny — one is the size of a grain of sand and can only be seen with special equipment, while the other, roughly the size of the tip of a crayon, is laser-printed on the reverse side of the glass somewhere along its black border or bezel. The codes are placed on the glass at different stages of manufacturing to help Apple track and reduce defects. They represent the company’s obsessive attention to detail in manufacturing devices such as the iPhone, which has helped it squeeze costs in a traditionally low-margin business.

“Apple has been granularly and singularly tracking many components in the iPhone for some time, but expanding that to the glass and doing it with a microscopic bar code is another level of obsessive attention to detail that few companies would do,” said Kyle Wiens, CEO of iFixit, a popular Apple gadget repair site. “I’ve never heard of serial numbers on the glass level, but if you’re throwing infinite money at improving your manufacturing knowledge, then why not?” Apple added the smaller of the two QR codes — 0.2 mm in width — to iPhone screens in 2020 so it can track precisely how many usable cover glass units its two Chinese suppliers, Lens Technology and Biel Crystal, are making and how many defective cover glass units they are throwing away during manufacturing. Lens and Biel have previously stymied Apple’s efforts to learn the true rate of defects, which can raise its production costs. Apple has paid millions of dollars to install laser and scanning equipment at Lens and Biel factories to both add the microscopic QR code and scan the cover glass at the end of the production process.