Patent ID: 7583580

Claim:
An optical recording medium configured for recording and reproduction when illuminated by light from a light source as near-field light using a focusing lens whose numerical aperture exceeds 1 , comprising: a composite layer, in which a high refractive index material portion having a refractive index higher than that of a light-transmissible material portion is mixed in the light-transmissible material portion, provided on the surface of a light incident side of said optical recording medium, wherein a refractive index n 1 of said high refractive index material portion is n1>NA with respect to a numerical aperture NA of said focusing lens, said high refractive index material portion is made of particles and an average particle diameter of said particles is equal to or less than one tenth of a wavelength in said composite layer of light that illuminates said optical recording medium, and said particles having a particle size of approximately 22 nm or less.