Methods for producing phase-difference film and circularly polarizing plate involving simultaneous reduction of clip pitch on one side and increase of clip pitch on another side

摘要

The present invention provides a method capable of producing a retardation film having an elongated shape, having high uniaxiality and a high in-plane alignment property, and having a slow axis in an oblique direction with high production efficiency. The production method for a retardation film of the present invention includes: holding left and right end portions of a film with left and right variable pitch-type clips configured to have clip pitches changing in a longitudinal direction, respectively; preheating the film; increasing the clip pitch of the clips on one side and reducing the clip pitch of the clips on another side, while extending a distance between the left and right clips, to obliquely stretch the film; maintaining or reducing the clip pitch of the clips on the one side and increasing the clip pitch of the clips on the another side so that the clip pitches of the left and right clips are equal to each other, while extending the distance between the left and right clips, to obliquely stretch the film; and releasing the film from being held with the clips.