I see the fine black line when using low brightness

Hello muhamad182,

Thanks for the additional information regarding your iPhone.

Have you tried restarting your iPhone? A restart can help to refresh the OS and connections. What apps are you using when this happens? We want to narrow down the cause of this issue. Is your iPhone fully updated? Often an update can resolve many issues and can also ensure your iPhone functions the best. In case you need to update, back up your iPhone to secure your data.

How to back up your iPhone, iPad, and iPod touch

Update your iPhone, iPad, or iPod touch

If the steps above don't help, reach out for additional support here: Get Support

Take care.

Hello muhamad182,

Thanks for reaching out in Apple Support Communities. We understand that you're seeing a fine black line on your iPhone screen, when using low brightness. We're happy to help. What is your iPhone model? Do you see this fine black line, when using specific apps? The more details we have the better we can help.

Check out the following support articles:

About the Super Retina display and Super Retina XDR display on your iPhone

If the screen isn’t working on your iPhone or iPad

Cheers!