Description of pixel density in screen

Pixel density is usually expressed in pixels per inch on the diagonal. The higher the density, the clearer and more delicate the displayed content.

For example, to calculate the PPI of a 5-inch mobile phone screen with a resolution of 1920*1080:

Pixel density is also divided into:
High pixel density: such as mobile phones and monitors
Low pixel density: such as LED displays

The PPI of LED displays is generally between 10-50