The Ipad, and many other sunlight viewable devices such as depth finders, Marine GPS, Marine radar displays, multi-function displays, etc... have Polarized shielding to prevent damage to the super-twist display. The test to determine if any device has this type of shielding is to look at the display with polarized glasses, they merely turn the device. If the screen blacks out, it has a Polaroid shield. If it remains clear, it is not shielded. Same test is used to determine if eyeglasses are Polarized.

Cheers,

Gary