Optically Diffusive Film and Optical System Including Same

An optically diffusive film comprising a plurality of particles dispersed in a binder and elongated along an in-plane block-direction orthogonal to an in-plane pass direction and a thickness-direction of the optically diffusive film, the particles having average lengths Lb and Lz along the respective pass- and thickness-directions, Lb/Lz greater than about 100, for at least a first wavelength in a visible wavelength range extending from about 420 nm to about 680 nm, a magnitude of a difference between indices of refraction of the particles and the binder along the block-direction being at least about 0.04, a magnitude of a difference between indices of refraction of the particles and the binder along the pass-direction being less than about 0.05,

• wherein, for a substantially collimated substantially normally incident light polarized along the block-direction and for the first wavelength, an optical transmittance of the optically diffusive film as a function of transmission angle comprises a substantially linear segment extending at least from about 10 degrees to about 60 degrees, the substantially linear segment having a best linear fit with an r-squared value greater than about 0.8.