A sunlight readable display can be read in direct sunlight. Often the term “sunlight readable” is used in reference to a TFT display having a super-bright backlight that overpowers the light of the sun to be visible. This typically occurs around 800 nits.
However, other display technologies achieve sunlight readable status without trying to overpower the sun. For instance, purely reflective displays, like epapers, are sunlight readable without a backlight. Additionally, transflective displays use a combination of the reflective and transmissive technologies to make sunlight readable displays with much less bright backlights.
Sunlight readable displays are a subset of daylight readable displays.