Sun light is too hot for iPAD / iPhone ?? Users sues Apple for over-heating
The normal operating temperature of iPhone or iPAD is between 0º and 35º C (32º to 95º F). So it could easily mean that while in a hot day, or under the sun, atmosphere around the device (Apple iPhone / iPad) is too hot for it to run and as an user you end up with a costly device showing this type of black screen.
It seems with global warming and all that, the half of the world is out of working temperature range for Apple iPhone and iPad.