Docomo SO-51A Instruction Manual page 8

The screen may become partially dark or the
･
colors may be changed if you set the display
brightness to brighter than necessary or use
the terminal extremely for a long time. Also,
unevenness of colors or brightness, or
changes of colors may be found depending
on direction you are looking. That is because
of the structure of organic EL display, not a
malfunction.
DOCOMO is not liable to any failures or
･
malfunctions for commercially available
optional equipment.
Precautions
6