The reading distance depends on the size of the characters that the display is capable of displaying. The reading distance does not depend on brightness. The following table shows the read range depending on size. By convention we refer only to character height.

Numerical modules (7 segments)
height in cm.	legibility distance in mt.
5,6	15-20
15	45-60
23	69-92
32	96-128
47	141-188

Alphanumerical modules (7x5 dot matrix)
height in cm.	legibility distance in mt.
3	9-12
5	15-20
8	24-32
11	33-44
16	48-64
20	60-80