Optical films for reducing color shift and organic light-emitting display apparatuses employing the same

An optical film, comprising:na high refractive index pattern layer including a first surface and a second surface facing each other,wherein the first surface includes a pattern having a plurality of grooves,the plurality of grooves each have a curved surface and a depth greater than a width thereof, andthe high refractive index pattern layer is formed of a material having a refractive index greater than 1; anda low refractive index pattern layer formed of a material having a refractive index smaller than the refractive index of the material constituting the high refractive index pattern layer,wherein the low refractive index pattern layer includes a filling material for filling the plurality of grooves,wherein a tilt angle, θ, of each groove satisfies the following condition, 15°≦θ≦75°,the tilt angle is an angle between a straight line and the first surface,the straight line connects an apex of the respective groove to a start point of an adjacent groove on the first surface, andlight incident through the low refractive index pattern layer is emitted through the second surface of the high refractive pattern layer.