Patent Number: 6,445,447

Title: Near field optical certifying head for disc asperity mapping

An optical certifying head flies above a disc surface within an evanescentdecay length of the disc surface. A light beam is focused through anobjective lens, and further focused through a SIL. The SIL-focused lightis coupled to the disc surface through near-field coupling. The light isreflected from the disc surface depending on a surface condition of thedisc such that the surface condition can be determined.

Inventors: Wang; Ling (Eden Prairie, MN), Li; Li (Bloomington, MN)


International Classification:

Expiration Date: 09/03/2014