The Digitizer is the touch panel that sits over the LCD screen. The digitizers job is to detect and map your fingers movements across the screen and let the phone know where your finger is.
The digitizer panel is a clear panel, usually bonded underneath or inside the front glass or plastic the sits on top of the LCD, they rarely malfunction but are very susceptible to impact damage, scratches and cracks
Common faults / issues with digitizers include:
Touch panel no longer responding - if you can see the picture ok but the device is not responding to touch
Touching the panel causes unexpected or erratic movements - this will require a replacement digitizer or re-calibration is available on the device
Impact damage - glass digitizers are very easily damaged, generally the will crack or shatter - depending on the extent of the damage it may still work but in not advisable due to safety
Scratches - plastic digitizers are very susceptible to scratches, several light scratches build up making the phone look tatty and harder to view
As the digitizer panel sits directly above the LCD panel some impact damage can also cause damage to the LCD.
The general rule is that if the screen is cracked but the picture device is displaying a picture as normal you will just need to replace the digitizer.
Part:Apple iPad 2 replacement digitizer / touch screen glass - Black
Digitizer electronics and cable - OEM
Glass panel aftermarket (Made to Apple specifications)
Apple iPad Mini 2
(aka iPad mini with Retina display)
Smaller screen (7.9in). Lightning port. Available in black or white. Retina display. Introduced November 2013.
Warranty: 12 Months