Is the display blank only after taking pictures, or blank all the time (i.e., can you see the menus)? If you can see the menus, try performing a Reset All
(page 67 in the manual). The idea here is to set the contrast/backlighting to factory presets.
The manual can be found here
If the display is blank all the time, try holding it near a bright light and look at it from different angles to see if you can see any image on the display (if the backlight isn't working, you may be still able to see items on the display). If that's the case, you may be able to navigate to the menus and perform a Reset All
Otherwise, pull the batteries out and leave them out for a longer period of time - several days, if possible. This should also reset the camera.
Failing this, you will likley need to send it in for repair.