US Patent 7821717 Lenticular lens array element

A lens element comprising: a rear substrate having a front surface provided with a surface relief having a plurality of zones each capable of providing a lens effect; a front substrate disposed in front of the rear substrate and having a rear surface provided with a surface relief having a plurality of zones each capable of providing a lens effect, the zones of the surface reliefs provided on the rear substrate and the front substrate having the same spatial arrangement over the area of the lens element; and solid or liquid, isotropic, intermediate material disposed between the front surface of the rear substrate and the rear surface of the front substrate, the intermediate material having a refractive index different from the refractive index of each of the rear substrate and the front substrate. This construction reduces the degree of Fresnel reflection which would otherwise degrade the optical performance.