If the glass is cracked but the image is intact and the sensor works — usually only the glass is replaced, and it's noticeably cheaper than a display assembly. But if stripes, spots, or dead touch zones appear under the cracks, the matrix is damaged, and there's no point in replacing the glass: it's glued to the matrix permanently.
A check you can do yourself
- Open a white screen (for example, a blank note) and look at it at an angle: stripes, dark spots, or streaks mean the matrix is damaged.
- Run your finger across the entire area — in the Calculator or keyboard you'll clearly see areas that don't respond.
- Look at the edges of the cracks: if an ink spot appears from under them, it will grow, and you shouldn't delay the repair.
- Check Face ID and the front camera: the glass over the sensors can also be damaged.
How the glass is replaced
An iPhone display assembly is a "sandwich" of glass, a polarizing layer, and a matrix, bonded together with optical adhesive. To replace the top layer, the module is disassembled on a special machine, the remaining adhesive is removed, new glass is installed, and it's laminated again under pressure. This is precision work: the matrix cannot tolerate overheating or bending. That's why cheap "glass replacement on the cheap" often ends with spots appearing a week later — and the customer pays for a new module.
When the module is replaced
When the matrix is damaged, when the sensor doesn't work on part of the screen, when there are spots and dead pixels, or when the glass is so broken that fragments are broken down to the matrix. The module is also installed when the device is needed urgently: glass replacement with lamination takes more time.
What's important after repair
Regardless of whether the glass or module was replaced, the housing needs to be resealed — the original adhesive is single-use. And it's worth checking Face ID, True Tone, and auto-brightness right away: if they're gone, it's not about the glass, but about the sensor assembly — there's a separate article about that, Face ID doesn't work after display replacement.