The minimum viewing distance of led displays means the minimum distance of displaying clear image of led displays. The minimum viewing distance is the distance at which the human eye perceives a LED pixel cluster as a single dot.
The minimum viewing distance of led display = pixel pitch（Distance between the mid-lines of two sets of LED lights）mm * 1000/1000
The minimum distance is calculated converting into meters the pixel pitch. For example, a led screen with 10mm pitch has a minimum viewing distance of 10 meters, while a 20mm pitch screen has a minimum viewing distance of 20 meters.
The maximum viewing distance of led display = 30* the height of led displays
So, If the height of the led display was 2m, then the maximum viewing distance is 60meters.
Therefore, the minimum viewing distance depends on the pixel pitch of the led display while the maximum viewing distance depends on the height of it.