Optical film production method, optical film, surface light-emitting body and optical film production device
An optical film production method for suppressing air bubbles in microlenses, comprising rotating a roll die having a plurality of concave-shaped microlens transfer portions on the surface and running a substrate in the rotation direction; supplying an active energy ray-curable composition β onto a coating roll adjacent to the roll die surface, flattening the composition β, coating the flattened composition β on the roll die surface; supplying an active energy ray-curable composition α on the substrate and coating the composition α on a surface of the substrate; associating the compositions α and β between the roll die and the substrate to form a liquid pool; and irradiating a region between the roll die surface and the substrate surface with an active energy ray so the compositions α and β are sandwiched between the roll die surface and the substrate surface to cure the compositions α and β.
1. An optical film production method having a plurality of convex-shaped microlenses disposed thereon, the method comprising the following steps A to F:
step A: rotating a roll die having an outer circumferential surface having a plurality of concave-shaped microlens transfer portions disposed thereon and running a substrate in a rotation direction of the roll die along the outer circumferential surface of the roll die;
step B: supplying an active energy ray-curable composition β onto a first coating roll disposed to be adjacent to the outer circumferential surface of the roll die, flattening the active energy ray-curable composition β on the first coating roll by a flattener, and coating the flattened active energy ray-curable composition β on the outer circumferential surface of the roll die by the first coating roll so as to fill the plurality of concave-shaped microlens transfer portions with the active energy ray-curable composition β;
step C: supplying an active energy ray-curable composition α onto a second coating roll disposed to be adjacent to the surface of the substrate and coating the active energy ray-curable composition α on a surface of the substrate by the second coating roll;
step D: associating the active energy ray-curable composition α coated on the surface of the substrate in the step C and the active energy ray-curable composition β coated on the outer circumferential surface of the roll die in the step B at an association portion between the roll die and the substrate to form a liquid pool;
step E: irradiating a region between the outer circumferential surface of the roll die and the surface of the substrate with an active energy ray in a state in which the active energy ray-curable composition α and the active energy ray-curable composition β associated in the step D are sandwiched between the outer circumferential surface of the roll die and the surface of the substrate to cure the active energy ray-curable composition α and the active energy ray-curable composition β; and
step F: peeling off a cured product obtained in the step E from the roll die,
wherein the flattener is any one of a doctor blade, an air blade, and an air knife.
2. The optical film production method according to claim 1 , wherein the roll die is pressed at a pressure of from 5 to 200 N by the first coating roll in the step B.
3. The optical film production method according to claim 2 , wherein an opening width between the first coating roll and the flattener is maintained in a range of from 0.01 to 0.4 mm in the step B.
4. The optical film production method according to claim 2 , wherein the active energy ray-curable composition α is flattened after the active energy ray-curable composition α is supplied in the step C.
5. The optical film production method according to claim 2 , wherein a convex shape of the microlens is at least one kind of a spherical segment shape, a truncated spherical segment shape, an ellipsoid spherical segment shape, a truncated ellipsoid spherical segment shape, a pyramidal shape, a truncated pyramidal shape, a conical shape, or a truncated conical shape.
6. The optical film production method according to claim 2 , wherein a viscosity of the active energy ray-curable composition β is from 10 to 3000 mPa·s.
7. The optical film production method according to claim 2 , wherein a viscosity of the active energy ray-curable composition α is from 10 to 3000 mPa·s.
8. The optical film production method according to claim 1 , wherein an opening width between the first coating roll and the flattener is maintained in a range of from 0.01 to 0.4 mm in the step B.
9. The optical film production method according to claim 1 , wherein the active energy ray-curable composition α is flattened after the active energy ray-curable composition α is supplied in the step C.
10. The optical film production method according to claim 1 , wherein a convex shape of the microlens is at least one kind of a spherical segment shape, a truncated spherical segment shape, an ellipsoid spherical segment shape, a truncated ellipsoid spherical segment shape, a pyramidal shape, a truncated pyramidal shape, a conical shape, or a truncated conical shape.
11. The optical film production method according to claim 1 , wherein a viscosity of the active energy ray-curable composition β is from 10 to 3000 mPa·s.
12. The optical film production method according to claim 1 , wherein a viscosity of the active energy ray-curable composition α is from 10 to 3000 mPa·s.
13. The optical film production method according to claim 1 , further comprising flattening the active energy ray-curable composition α on the second coating roll by any one of a doctor blade, an air blade, and an air knife, in the step C.