PH4mm led display is definitely indoor used led display. Pixel density is 62500 dots per sqm which means it only need 1sqm play video. It is 1/16 or 1/32 scanning to reduce IC card numbers with reasonable brightness.
PH4mm full color led display is less frequently used than P7.62mm and P6mm. It can be made as small as TV to play video. In subway train, PH4 mm full color led display can be used to show trains and stations information.
High brightness, short viewing distance, big size, high definition, small pixel pitch make the indoor PH4mm SMD LED display an ideal resolution in all indoor advertising field. The viewing distance can be as short as 1 meter, as far as 200 meters, has a overwhelming advantage to LCD panels.