US Patent 7285323 Optical multilayer film, polarizing plate and optical product

An optical multilayer film comprising a hard coat layer and a low refractive index layer comprising aerogel, which layers are laminated, in this order, directly or with another intervening layer on one surface of a base film comprising a transparent resin, wherein the refractive index nH of the hard coat layer and the refractive index nL of the low refractive index layer satisfy the following three formulae [1], [2] and [3],1.25≦nL≦1.37 Formula [1]nH≧1.53 Formula [2](nH)1/2−0.2<nL<(nH)1/2+0.2. Formula [3.]