FILM, PROTECTIVE FILM FOR POLARIZER AND POLARIZING PLATE

摘要

PROBLEM TO BE SOLVED: To obtain an optical film in which a phase difference is hardly caused but the development of the phase difference and its wavelength dependence can be controlled by changing the composition ratio. SOLUTION: The film has <=3 nm phase difference for the light at 515 nm wavelength and <=5 nm phase difference in the thickness direction for the light at 515 nm wavelength. The value (A) defined by A=Re(442)-Re(780), wherein Re(442) is the phase difference for the light at 442 nm wavelength and Re(780) is the phase difference for the light at 780 nm wavelength, ranges from -3 nm to 3 nm.