If you restored the iOS software, there is not much else that you can do on your end to fix it. Since you do have sound, but the screen has gone black, it appears as though the device is working, but that the screen has fine bad.
Take it to an Apple Store and let them have a look. Apple does not repair iPads, but they offer an out of warranty replacement device if your iPad qualifies and if you are willing to purchase a refurb. The cost of these iPads starts at $250.00 in the U.S.
Apple offers two service options for iPads that are not eligible for warranty service.
If your iPad requires service only because the battery's ability to hold an electrical charge has diminished, please refer to the Battery Replacement Service information. If you own an iPad that is ineligible for warranty service but is eligible for Out-of-Warranty (OOW) Service, Apple will replace your iPad with an iPad that is new or equivalent to new in both performance and reliability for the Out-of-Warranty Service fee listed below.
| iPad model | Out-of-Warranty Service Fee |
|---|
| iPad mini | $219 |
| iPad 3rd, 4th generation | $299 |
| iPad 2, iPad | $249 |
A $6.95 shipping fee will be added if service is arranged through Apple and requires shipping. All fees are in US dollars and are subject to local tax.
Certain damage is ineligible for out-of-warranty service, including catastrophic damage, such as the device separating into multiple pieces, and inoperability caused by unauthorized modifications. However, an iPad that has failed due to contact with liquid may be eligible for out-of-warranty service.
Apple reserves the right to determine whether or not your iPad is eligible for Out-of-Warranty service. Replacement iPads have a 90-day limited hardware warranty or assume the remainder of your standard warranty or AppleCare service contract coverage, whichever is longer. Please see the AppleCare+ for iPad and Apple Repair Terms And Conditions for further details.