Lines or Coloured Patches on Your Phone Screen? Here's What It Means

You pick up your phone and there it is — a green line running down the screen, a patch of purple where the display should be clear, or half the screen that’s gone dark and unresponsive. The phone itself works fine, but the display is clearly wrong. Here’s what’s actually going on and what your options are.

What’s Causing It

Lines, coloured patches, and dead sections on a phone screen are almost always caused by damage to the display panel itself — specifically the OLED or LCD layer underneath the glass. This can happen in a few ways:

• A drop or impact: The most common cause. Even a phone that lands face-up and doesn’t crack the glass can damage the display panel underneath. The panel is fragile, and impact can cause internal fractures that show up as lines or patches.
• Pressure on the screen: Sitting on your phone, putting it in a bag with something heavy pressing against it, or bending it can stress the panel and cause the same symptoms.
• Water or liquid damage: If liquid gets inside the phone and reaches the display connectors, it can cause patches, discolouration, or lines as the connection between the display and the board corrodes.
• A failing display connector: Less common, but sometimes the ribbon cable connecting the display to the motherboard comes loose or wears out — this can cause intermittent lines or sections going dark without any obvious impact.

The Different Things You Might See

Different symptoms point to slightly different issues, though the fix is usually the same:

• A single vertical or horizontal line — typically a crack in the display panel, often running from the point of impact.
• Green, purple, or white patches — the pixels in that area have failed, usually from internal panel damage or liquid.
• Half the screen dark or unresponsive — the panel has cracked across the middle, or a display connector has come loose.
• Flickering or screen going black randomly — can be a loose connector or, on older phones, a failing backlight.
• Touch not working in a certain area — the digitiser (the touch layer) is separate from the display in some phones, and damage to that layer causes dead zones without affecting the picture.

Will It Get Worse?

In most cases, yes. A cracked display panel tends to spread over time, especially if the phone is still being used and absorbing minor bumps and vibrations. A small line can grow into patches, and patches can spread until the screen is largely unusable. If the phone is still functional and you’re using it with the damage, there’s a good chance the display will deteriorate further before you get it sorted.

It’s also worth knowing that a damaged screen leaves the internal components more exposed to dust and moisture, which can lead to further problems down the line.

Can It Be Fixed?

Yes, in almost every case. Screen replacement fixes lines, patches, dead zones, and unresponsive touch in one go, because the replacement includes both the display panel and the digitiser. Most screen replacements at Voltrex take 15–30 minutes depending on the model.

The only situation where a screen swap doesn’t solve it is if the damage has extended to the motherboard itself — this is rare and usually only happens after serious water damage or a very heavy impact. We’ll be able to tell you which situation you’re in after a quick look.

iPhone vs Samsung: Does It Matter?

Both can develop lines and patches after damage, but iPhone OLED panels (iPhone X onwards) tend to show green lines specifically along the edge of an internal crack, which is a very recognisable pattern. Samsung AMOLED displays often show purple or black spreading from a corner after a drop. The cause and the fix are the same — screen replacement. Different phone models have different screen costs, so bring it in and we’ll give you a quote on the spot.