화면을

화면을

"화면을" means "the screen" (as an object in a sentence).

In this example, '화면을' mentions the screen as the content being captured.

화면을 캡처해서 친구에게 보냈어요.

I captured the screen and sent it to my friend.

In this sentence, '화면을' refers to the action of activating or using the screen (as an object).

화면을 켜서 영화를 보세요.

Turn on the screen and watch the movie.

Here, '화면을' is used to point out the issue related to the screen when it's looked at for a prolonged time.

화면을 너무 오래 쳐다보면 눈이 피곤해질 수 있어요.

Staring at the screen for too long can tire your eyes.