The green line running down a Samsung phone or an iPhone is feared almost as much as the blue screen of death in Windows PCs.
This problem can be considered relatively new, as you’ll notice it didn’t happen when smartphones used LCD panels. The problem started appearing in Samsung phones in 2016 and in iPhones in 2017, around the time each brand started adopting OLED and AMOLED display panels.
The cause of this line cutting vertically through the screen was wrongly thought to be a software problem, as it started after a major Android update, but later, we now know that it’s not a software problem; it’s a hardware problem that happens specifically with AMOLED and OLED displays.
The Green Line explained:
The main difference between an LCD panel and an OLED panel is that in the OLED, each individual pixel generates its own light, while the LCD panel depends on a backlight to power the screen.
So, while near the end of an LCD panel’s life the backlight may turn off, causing the screen to go dark or “die” all at once, OLED and AMOLED screens start to experience pixel issues. That green line means a ribbon cable is either broken or causing a short circuit, causing an entire column of pixels to receive maximum voltage at all times, showing that green line, meaning that column is no longer working.