The present invention discloses an optical assembly. The optical assembly comprises: a first optical film comprising a first surface; an adhesive disposed on the first surface of the first optical film; and a second optical film comprising a second surface, wherein the second surface of the second optical film comprises a plurality of microstructures, wherein the plurality of microstructures are bonded to the adhesive; wherein the adhesive is made of a first material and the plurality of microstructures are made of a second material, wherein the hydrophilic/hydrophobic characteristic of the first material is configured with respect to the hydrophilic/hydrophobic characteristic of the second material such that the adhesive force between the adhesive and the plurality of microstructures of the second optical film is greater than 100 g/25 mm and the optical gain of the optical assembly is greater than 1.5.