An Illuminant module includes an optical film and a light source array. The optical array includes a plurality of concave surfaces and a plurality of convex surfaces alternatively arranged along at least one direction, wherein each concave surface has a concave surface width along the at least one direction, and each convex surface has a convex surface width along the at least one direction. The light source array includes a plurality of light emitting diodes, wherein the concave surface width is not equal to the convex surface width, and the light from the light source array penetrates the optical film.