We have proposed the novel optical model for layer structure film to precisely control light diffusion angle range. By introducing structure characteristics to the phase grating model, we successfully constructed the novel optical model. In addition, we clarified that difference of refractive indices of layer structure and layer width are important factors for precisely control of light diffusion angle range.

We investigated effects of ultraviolet illuminance and ratio of high- to low-refractive-index monomers on the layer structure and light diffusion properties of light-diffusing films with alternating polymer layer structures. We clarified that an increasing difference in refractive index between alternating polymer layers induced an increase in the diffusion angle.