Method of producing mold for microlens array through cutting

A method of producing a mold for a microlens array provided with plural microlenses through cutting with a cutting tool that rotates around a rotation axis, wherein the plural microlenses have optical axes in the same direction and the substantially same shapes and the mold has plural surfaces corresponding to surfaces of the plural microlenses, the method comprising:

• cutting a surface of the mold, the surface corresponding to a microlens surface and having the central axis corresponding to the optical axis of the microlens, while each of a value of angle θ between the rotation axis of the cutting tool and a straight line passing through a point on the rotation axis and parallel to the central axis of the surface and a value of angle φ between a plane containing the rotation axis of the cutting tool and the straight line passing through a point on the rotation axis and parallel to the central axis of the surface and a reference direction perpendicular to the straight line passing through a point on the rotation axis and parallel to the central axis of the surface is kept constant;
• and
• cutting the plural surfaces of the mold corresponding to the plural microlens surfaces while the values of angle θ and angle φ for the plural surfaces of the mold are determined such that a variance of the values of at least one of angle θ and angle φ for the plural surfaces of the mold is greater than a predetermined value to sufficiently reduce a change in illuminance on a surface illuminated using a microlens array produced using the mold.