Green Lines, Ghost Touch and Flicker: What Your Screen Is Telling You

Some screen faults are dramatic. A green line marching down the display, a black inkblot that keeps spreading, or a phone tapping and typing away on its own like it's possessed. They look alarming, and understandably people fear the worst. The good news is we see these every week and most are fixable. The important thing to know is that they rarely stay still, so the sooner it's looked at, the better. Here's what each of these symptoms usually means and what can be done about it.

Green or pink lines down the screen

A bright vertical line, most often green but sometimes pink, red or white, running from top to bottom is one of the classic ones. It usually points to a problem with the display panel itself or the thin ribbon connector that links it to the phone's brain. Sometimes it appears out of nowhere, sometimes days or weeks after a drop that seemed harmless at the time. A knock can quietly disturb the connector or start a tiny fault in the panel that only shows itself later. The line might start as a single thread and then multiply, or the display might gradually fill with colour until half of it is unusable. In the great majority of cases the fix is a new screen, and once that's fitted the phone is right back to normal.

Ghost touch: when the phone taps by itself

Ghost touch is the eerie one. The phone registers taps and swipes that you're not making. It opens apps on its own, types nonsense into messages, or becomes impossible to control because it's fighting you the whole time. It's caused by the touch layer of the screen misfiring, and there are a few culprits. A cracked or failing screen is the usual one. A cheap, poor-quality replacement screen fitted somewhere down the line is another big one, which is exactly why we bang on about fitting proper screens in our post on whether a cracked screen is worth repairing. Occasionally it's a dodgy charger feeding the phone noisy power, so if it only happens while plugged in, try a different cable and plug first. But if it's happening off the charger too, the screen is almost certainly the problem, and a quality replacement sorts it.

Black blotches and spreading ink

A dark patch, often looking like spilled ink or a bruise, that grows over time is damage to the display panel, usually from a knock or from pressure, such as sitting on the phone or it being squashed in a tight pocket. On the OLED screens most phones now use, once the panel is damaged like this it doesn't heal and it doesn't stop. The blotch spreads, the colours bleed, and what starts as a small mark in the corner can take over the whole screen within days. This is one where waiting genuinely costs you, because a phone that's mostly usable today can be a black rectangle by the weekend. A new screen puts it right, but it's worth doing before the fault spreads far enough to make the phone unusable in the meantime.

Flicker, dimming and half-lit screens

A screen that flickers, strobes, keeps dimming for no reason, or lights up only half-way can mean a few different things. It might be the display or its connector again, it might be a backlight fault, or on occasion it's a software or settings hiccup rather than hardware. The quick things worth trying first: restart the phone, check the brightness isn't set to auto in a way that's overreacting to the light in the room, and make sure it's fully up to date. If a flicker survives all that, it's a hardware fault and worth bringing in. One thing to rule out along the way is heat, since a phone that's overheating can behave oddly with its display, and we cover that in our guide on why phones overheat.

Could it be water rather than a drop?

Not every screen fault starts with a bang. Liquid getting inside the phone can cause lines, flicker, patches and ghost touch too, sometimes days after the phone got wet, as corrosion creeps across the connectors. If your phone has had any kind of soaking recently, even one you thought it had survived, mention it to us, because the fix might involve more than just the screen. Our water damage first-aid guide explains what to do and, just as importantly, what not to.

Is it always fixable?

Most of the time, yes. The overwhelming majority of these faults are screen problems, and a new screen is a same-day repair on most phones. Where it gets more involved is if the fault sits deeper than the screen, in the connector socket on the board or in the graphics side of the phone's main chip. That's rarer, but it does happen, particularly after a hard knock or water. The only way to know for sure is to open the phone up and test it, which we do as part of a free quote. We fit a test screen to see whether a new display alone clears the fault, and if it does, you're sorted. If it turns out to be something deeper, we'll tell you honestly what it'll take and whether it's worth it.

Why acting fast genuinely matters here

With a lot of phone problems there's no harm in waiting a bit. These are not those problems. Screen faults like spreading blotches and multiplying lines tend to get worse, not better, and a phone that's still mostly usable now gives us a much easier job than one that's gone fully dark. There's also a practical angle: while the screen still works, you can back up your photos and messages. Once it's black you can't see to do that, and getting your data off a dead-screen phone is a bigger faff for everyone. So if you're seeing any of this, don't sit on it.

Bring it in

Whatever your screen's doing, we'll take a proper look and give you a free, honest quote before touching anything. We handle iPhone, Samsung and Android and iPad screens, and most are a same-day fix. You'll find us at 5 The Fairings, right in the middle of Tenterden, opposite the Waitrose car park.