Optical construction and display system incorporating same

An optical construction comprising:

• a reflective polarizer layer comprising alternating layers, wherein at least one of the alternating layers comprises a birefringent material;
• and
• an optical film comprising a plurality of interconnected voids comprising surface voids and interior voids, the optical film disposed on the reflective polarizer layer and having an optical haze that is not less than about 50%, an optical clarity that is not greater than about 10% and an effective index of refraction that is less than about 1.4, wherein substantial portions of each two neighboring major surfaces in the optical construction are in physical contact with each other, and wherein the optical construction has an axial luminance gain that is not less than about 1.2 and a thickness that is not less than about 1 micron.