PURPOSE: To provide a polycarbonate phase-difference compensating film with the retardation value controllable in an appropriate range and with the variance of retardation values remarkably reduced.
CONSTITUTION: This phase-difference compensating film consists of the drawn film or sheet of a polycarbonate having a repeating unit shown by formula I or the repeating units shown by formulas I and II and having 0.5-2.5dl/g reduced viscosity (ηsp/c). In the formulas, X is a unit expressed by formula III, R1 to R3 and R5 to R12 are each a halogen atom, alkyl, cycloalkyl or aryl R4 is hydrogen atom, an alkyl or cycloalkyl, (a) to (f) and (i) to (k) are each an integer of 0 to 4, (g) and (h) are an integer of 0 to 2, Z is a single bond, -O-, -CO-, -S-, -SO-, -SO2- or -CH2-, and Y is a single bond, -O-, -CO-, -S-, -SO-, -SO2-, etc.
SAKAMOTO HIDEJI
MORISHITA HIRONOBU
NAGAO TOMOHIRO
