METHOD FOR PRODUCING PHASE-DIFFERENCE FILM AND METHOD FOR PRODUCING CIRCULARLY POLARIZING PLATE

摘要

The present invention provides a method for producing, with high production efficiency, a longitudinally oriented phase-difference film having a slow axis in the diagonal direction, and having high uniaxiality and high in-plane orientation. This method for producing the phase-difference film includes: holding the left and right end sections of a film by using left and right clips of an adjustable pitch type for changing the clip pitch in the vertical direction; preheating the film; diagonally stretching the film by increasing the distance between the left and right clips while increasing the clip pitch of one clip and reducing the clip pitch of another clip; diagonally stretching the film by increasing the distance between the left and right clips while maintaining or decreasing the clip pitch of the one clip and increasing the clip pitch of the other clip so as to make the clip pitch of the left and right clips equal; and releasing the clips holding the film.