Whether you have a cracked iPad 2, 3, 4, Mini, or iPad Air, you can get your screen fixed at Jet City Device Repair.
And get a lifetime warranty included for free.
Glass: Sits on top, and does nothing but cover the layers below and shatter on impact.
Digitizer: Senses your finger touches. On iPads this is glued directly to the bottom of the glass. It's always replaced with a screen repair.
LCD: Displays the picture and is a completely separate from the glass/digitizer. May be black, white, rainbow, or a combination of these when broken.