Patent ID: 8270079
Filing Date: 2012-09-18
Classification: A44C,G02B

Abstract:
1. An article comprising at least one surface bearing at least one optical diffraction grating, wherein: (a) the article comprises a first dielectric material that is substantially transparent over at least a first region of the visible electromagnetic spectrum; (b) the diffraction grating comprises a plurality of elevated spatial regions and recessed spatial regions; (c) the diffraction grating further comprises a second dielectric material that is substantially transparent over at least a portion of the first spectral region and that substantially covers the elevated and recessed regions; (d) the diffraction grating further comprises a third dielectric material having optical transmissivity differing from that of both the first and second dielectric materials or having a refractive index differing from that of both the first and second dielectric materials over at least a portion of the first spectral region; (e) either (i) at least a portion of each elevated region comprises the first dielectric material and the third dielectric material at least partly fills the recessed regions or (ii) at least a portion of each elevated region comprises the third dielectric material and the second dielectric material substantially fills the recessed regions; and (f) the third dielectric material is absent from certain areas of the diffraction grating so that the first and second dielectric materials are in contact in those areas from which the third dielectric material is absent.