Method and apparatus for producing combined optical film, combined optical film, image display, and methods for producing liquid crystal panel and laminated optical film

1. A method for producing a combined optical film comprising a plurality of optical films each having at least one end face at which the optical films are opposed to one another, comprising the steps of:

(1) opposing the end faces of the optical films to one another with a gap provided therebetween;

(2) bonding a first seal material to the opposed portions of the optical films on a first side of each optical film to join the optical films;

(3) bending the joined opposed portions of the optical films such that the joined opposed portions become concave on a second side of each optical film where the first seal material is not bonded and such that the gap is narrowed on the second side;

(4) bonding a second seal material to the opposed portions on the second side, while the joined optical films are bent such that the gap is narrowed on the second side; and

(5) cancelling the bending of the joined optical films to make them flat.

2. The method according to claim 1 , wherein the first and second seal materials each have flexibility.

3. The method according to claim 1 , wherein the opposed end faces of the optical films are both substantially perpendicular to their front and back surfaces.

4. The method according to claim 1 , wherein in the step (1), the optical films are opposed to one another such that the gap between the opposed end faces has a width of 50 μm or less.

5. The method according to claim 1 , wherein the optical films are polarizing plates.

6. The method according to claim 1 , wherein the optical films each comprises an optical film and an easily-releasable protective film provided on the front surface of the optical film and/or a separator provided on the back surface of the optical film with a pressure-sensitive adhesive layer interposed therebetween.

7. The method according to claim 1 , further comprising the step of: (6) separating the first seal material after the steps (1) to (4) and before, after or simultaneously with the step (5).

8. The method according to claim 7 , wherein

the optical films each comprises an optical film, an easily-releasable protective film provided on the front surface of the optical film and a separator provided on the back surface of the optical film with a pressure-sensitive adhesive layer interposed therebetween,

in the step (2), the first seal material is bonded to the opposed portions on the separator side,

in the step (4), the second seal material is bonded to the opposed portions on the protective film side, and

in the step (6), the first seal material is separated together with the joined separators.

9. The method according to claim 7 , wherein

the optical films each comprises an optical film, an easily-releasable protective film provided on the front surface of the optical film and a separator provided on the back surface of the optical film with a pressure-sensitive adhesive layer interposed therebetween,

in the step (2), the first seal material is bonded to the opposed portions on the protective film side,

in the step (4), the second seal material is bonded to the opposed portions on the separator side, and

in the step (6), the first seal material is separated together with the joined protective films.

10. A method for producing a laminated optical film, by the method according claim 7 comprising

providing the surface of the combined optical film from which the first seal material is separated; and

bonding the surface of the combined optical film to another optical film with a pressure-sensitive adhesive layer interposed therebetween.

11. The method according to claim 10 , wherein the another optical film is a brightness enhancement film.