Patent ID: 7932347

Claim:
A polymer comprising a repeating unit represented by the following general formula (II) wherein X 1 , Y 1 , X 2 and Y 2 each independently represent a fluorine atom or alkylthio group (with X 1 and Y 1 optionally having their alkyl portions linked to form an alkylenedithio group, and X 2 and Y 2 optionally having their alkyl portions linked to form an alkylenedithio group), with the proviso that X 1 and Y 1 may together form a carbonyl or thiocarbonyl group with their bonding carbon atom, and X 2 and Y 2 may together form a carbonyl or thiocarbonyl group with their bonding carbon atom, and Z 1 is a group represented by any of the following formulas (i)-(ix), with the proviso that R 1 , R 2 , R 3 and R 4 each independently represent hydrogen or a substituent