MANUFACTURING METHOD AND MANUFACTURING DEVICE OF OPTICAL FILM

PROBLEM TO BE SOLVED: To provide a manufacturing method and a manufacturing device of an optical film which suppresses whisker and fluff on an end part of the optical film and crack of the optical film upon cutting when obtaining the optical film by cutting both end parts of a long-sized oriented film.SOLUTION: A manufacturing method of an optical film F includes a cutting process. In the cutting process, both end parts Ta, Tb in a width direction of a long-sized obliquely oriented film are cut respectively by means of a first cutting part 8a and a second cutting part 8b. A part which remains after cutting is obtained as the optical film F. In the cutting process, on each of the first cutting part 8a and the second cutting part 8b, an upper blade 10a is arranged on the side to which an angle θ formed between a face S forming a toe angle of the upper blade 10a and an orientation direction of the long-size obliquely oriented film F is decreased as the upper blade 10a is inclined to the direction to which the toe angle for a lower blade 10b, of the side of one aide and the side of the other side of the width direction for the lower blade 10b is increased, and the long-size obliquely oriented film F is held between the lower blade 10b and the upper blade 10a and is cut.SELECTED DRAWING: Figure 4 【課題】長尺斜め配向フィルムの両端部を切断して光学フィルムを取得する際に、光学フィルムの端部におけるヒゲや毛羽立ち、切断時の光学フィルムの破断を抑える。【解決手段】光学フィルムＦの製造方法は、切断工程を有する。切断工程では、長尺斜め配向フィルムの幅手方向の両端部Ｔａ・Ｔｂをそれぞれ第１の切断部８ａおよび第２の切断部８ｂによって切断する。切断して残った部分は光学フィルムＦとして取得される。上記切断工程では、第１の切断部８ａおよび第２の切断部８ｂのそれぞれにおいて、下刃１０ｂに対する幅手方向の一方の側および他方の側のうち、下刃１０ｂに対するトー角が増大する方向に上刃１０ａを傾けるにつれて、上刃１０ａの上記トー角を形成する面Ｓと長尺斜め配向フィルムＦの配向方向とのなす角度θが小さくなる側に、上刃１０ａを配置し、下刃１０ｂと上刃１０ａとで長尺斜め配向フィルムＦを挟み込んで切断する。【選択図】図４