It converts the picture signal into the row and column drive the LCD needs, and it is the usual cause of a picture that is split down the middle, has vertical bands, or shows a negative or washed out image.
Match by board number first. T-con numbers are printed on the board itself, often as two lines such as 6870C-0502B and 6871L-3708B, and either line is enough to identify the part. Model numbers help confirm the screen size the board was built for.
If the set has sound and backlight but a distorted picture, the T-con is the part to change before the panel is suspected. Ships from US stock with tracking.