Optically diffusive film with elongated structures

An optically diffusive film comprising:

• an optical substrate layer comprising opposing first and second major surfaces;
• and
• an optical layer disposed on the second major surface of the optical substrate layer and comprising a structured major surface facing away from the optical substrate layer and comprising a plurality of spaced apart elongated structures elongated along a same first direction and arranged at a substantially uniform density across the structured major surface, each elongated structure comprising a peak such that in a plane of a cross-section of the elongated structure that is parallel to the first direction and comprises the peak, the elongated structure has a length L1 and a height variation of less than about 5% across a substantially flat top region having a length d, d/L1≥0.15;
• wherein for substantially normally incident light and a visible wavelength range from about 450 nm to about 650 nm and an infrared wavelength range from about 930 nm to about 970 nm, the optical substrate layer has an average total transmittance or reflectance of greater than about 60% in the visible wavelength range and an average specular transmittance of greater than about 60% in the infrared wavelength range.