| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method of an optical film which suppresses occurrence of bright-spot foreign matters sufficiently even when an optical film containing a phase difference increasing agent is produced over a long time.SOLUTION: A production method of an optical film includes a first step of forming a film by using a resin solution containing a transparent resin and a solid phase difference increasing agent of a number average molecular weight of 50-1,000, and a second step of subjecting the film to a specified treatment, while carrying the film in an enclosed first region, to form an optical film. In the second step, the average temperature of the first region is 20°C or more lower than a glass transition temperature Tg of the transparent resin, and a collection member capable of collecting the scattering of the phase difference increasing agent is arranged in one or more parts in the first region, including low-temperature parts 30°C or more lower than the average temperature. |
