The highest display resolution of the LG 49UF640 is 4K Ultra HD. That's over four times the display resolution of a Full HD TV, which is the most common display resolution. 4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
A 4K Ultra HD HD type is in fact the best display resolution amongst all mid-size TVs that have been around for more than a year.
Amongst similar types of TV the worst display resolution is HD Ready.
4K Ultra HD TVs have a resolution of 3840 x 2160 pixels.
There are a number of other 4K Ultra HD TVs currently available which you might want to consider including the LG 40UF695 which is cheaper.