| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical film having functions as a polarizer protective film and a luminance improvement function, and a solution film-forming method with which it is possible to produce the optical film in extended length.SOLUTION: A flow casting film is formed by successively flow-casting a first dope and a second dope on a running belt, and stripped off from the belt to form a wet film. A protrusion and a recess are formed by a shaping roller in the second layer of the wet film formed from the second dope. This wet film is introduced into a heating chamber, and is heat-treated by being conveyed for at least 15 minutes there. An optical film is obtained by this heating. The obtained optical film includes a cellulose acylate layer 21 and a hardened layer 22. The hardened layer 22 has higher refractive index than that of the cellulose acylate layer 21, and has a plurality of prisms 22a at a boundary with the cellulose acylate layer. A prism sheet 16 is obtained from this optical film.SELECTED DRAWING: Figure 2 |
