As illustrated, your iPad screen has some defective pixels.
Stuck or dead display pixels are unusual - but not unknown. There is an industry-wide scoring formula that is used to determine whether or not one or more pixels are considered to be a warranty defect.
If you have benefit of an active AppleCare+ plan, you should be able to have your iPad repaired by Apple for a small excess/deductible fee.
You might be well advised to visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to assess your iPad - and you can explore your available options:
Genius Bar Reservation and Apple Support Options - Apple
iPad Repair & Service - Apple Support