field-sequential color tv

NOUN
25 LETTERS · STARTS WITH F

field-sequential color tv is a valid 25-letter word worth 40 points in Scrabble and 47 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
F4I1E1L1D2-0S1E1Q10U1E1N1T1I1A1L1C3O1L1O1R1T1V4
4 + 1 + 1 + 1 + 2 + 0 + 1 + 1 + 10 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 0 + 3 + 1 + 1 + 1 + 1 + 0 + 1 + 4 =40 PTS
DOUBLE WORD → 80TRIPLE WORD → 120
MEANING

What does field-sequential color tv mean?