Optical film, surface light emitting body, and method for producing optical film
An optical film has a plurality of aligned convex microlenses, each of which has a region α and a region β, region β forming the outer part of the convex shape of the microlens and positioned so as to cover region α. Both region α and region β contain a resin, and the refractive index of the resin in region α is higher than the refractive index of the resin in region β; region β contains fine particles, and region α contains fine particles, and the content of the fine particles contained in region α is lower than the content of the fine particles contained in region β; or region α contains fine particles, and region β contains fine particles, and the content of the fine particles contained in region α is higher than the content of the fine particles contained in region β.
1. A method for producing an optical film provided with a plurality of aligned convex microlenses comprising the following steps A to D that are sequentially performed:
step A: a step of rotating a roll mold having an outer peripheral surface provided with a plurality of aligned concave microlens transfer units, applying an active energy ray curing composition B onto the outer peripheral surface of the roll mold while making a base material travel in a rotational direction of the roll mold along the outer peripheral surface of the roll mold, and filling a part of a concave shape of the microlens transfer units with the active energy ray curing composition B;
step X: a step of irradiating the active energy ray curing composition B with an active energy ray;
step B: a step of providing an active energy ray curing composition A to between the outer peripheral surface of the roll mold and the base material;
step C: a step of irradiating a region between the outer peripheral surface of the roll mold and the base material with an active energy ray, in a state in which the active energy ray curing composition A is interposed between the outer peripheral surface of the roll mold and the base material; and
step D: a step of separating a cured product obtained in the step C from the roll mold.
2. The method for producing an optical film according to claim 1 , wherein application of the active energy ray curing composition B in the step A is application for making the active energy ray curing composition B follow a surface of the concave microlens transfer unit on the outer peripheral surface of the roll mold.