Patent ID: 7602674

Claim:
An optical recording system including a recording/reproducing optical head having an objective lens and an optical radiation source for emitting light having a wavelength of between 300 nm and 500 nm, and an optical recording medium recorded and reproduced with irradiation of light thereon from said optical head, said irradiation of light being made by the objective lens of which numerical aperture is larger than 1 when irradiated with a light wavelength of substantially 400 nm, said optical recording medium comprising at least a silicon oxide layer and a silicon layer being formed over a substrate in that order, wherein said silicon layer has formed thereon a protective layer of which refractive index is larger than a numerical aperture of said objective lens, and wherein said objective lens is comprised of a system of two lenses, at least one of which is a solid immersion lens (SIL) and said solid immersion lens is shaped like a conical surface; wherein said silicon oxide layer is formed directly on said substrate, said silicon layer is formed directly on said silicon oxide layer, and said protective layer is formed directly on said silicon layer, and wherein both said silicon layer and said protective layer have a refractive index larger than a numerical aperture of said objective lens when irradiated with a light wavelength of substantially 400 nm.