| abstract |
An optical material is a mixture of materialsncomprising a first material having a refractive indexnof not more than 1.45 for the d-line and a secondnmaterial having an Abbe's number, indicating wavelengthndispersion in the visible region, of not more than 25.nA relation between the refractive index for the d-linen(n d ) and the Abbe's number (ν d ) is defined as follows:n n d ≤ -6.667 × 10 -3 ν d + 1.70. |