The visibility angle of a screen is by convention the angle within which the brightness of a display is equal to the 50% of the frontal luminosity.
For example, a
LED screen with 5000 NIT frontal luminosity (NIT = millicandels/sq) has a visibility angle equal to the angle by which the brightness is reduced to 2500 NIT. This visibility angle can vary depending on the LED and the technical features of the display.
Images
Observation Point: Frontal = 5000 NIT; Lateral = 2500 NIT