Optical film and preparation method therefor and application thereof

A preparation method for an optical film, comprising:

• performing an alignment treatment on a first release film to obtain a carrier film;
• unrolling the carrier film, coating a surface of the carrier film with a first liquid crystal mixture used for preparing a brightness enhancement film, then drying and ultraviolet irradiation curing to form the brightness enhancement film;
• and coating a surface of the brightness enhancement film with photosensitive monomers, and photo-crosslinking under linear polarization ultraviolet irradiation to form a cross-linked polymer film as an alignment layer;
• coating the alignment layer with a second liquid crystal mixture used for preparing a phase retardation film, then drying and ultraviolet irradiation curing to form a liquid-crystal phase retardation film;
• and
• combining a second release film on a side of the liquid-crystal phase retardation film and rolling, peeling off the first release film, applying an optically clear adhesive (OCA) onto the brightness enhancement film, and combining a third release film on a side of the OCA facing away from the brightness enhancement film and rolling.