Patent ID: 8279721

Claim:
A near-field optical head, comprising: a light source; a light guiding member; a scattering member having a substantially flat-plane shape and an end; a photodetector; and a slider holding said light source, said light guiding member, said scattering member and said photodetector, wherein: said slider holds said scattering member such that said end of said scattering member is proximate to a medium; said scattering member has a first plane disposed on one side of said light source and substantially perpendicular to the medium, and a second plane opposite said first plane; said light source is configured to emit light such that the light irradiates said first plane substantially perpendicularly; said scattering member includes a substantially flat-plane shaped conductive scattering body having said first plane, and configured to generate the near field light, and a holding member holding said scattering body; said light guiding member includes a prism, said prism is in the same plane as said scattering member, said prism has an incidence plane which fixes said light source, an emission plane substantially parallel to said first plane of said scattering body and a bottom substantially parallel to the medium and is configured to transmit the light emitted from said light source such that the light emitted from said light source irradiates the entirety of said first plane of said scattering body, and is configured to guide a radiant beam from said light source substantially along said bottom of said prism such that a center of the radiant beam from said light source is brought to a gravity center of said scattering body; said end of said scattering member is configured to generate near field light and is configured to apply the near field light to the medium provided with a phase-change material to change the phase of the medium to thereby form a record mark in the medium with the near field light; and said photodetector faces said second plane of said scattering member and is configured to directly detect light reproduced from the medium.