CPC G02B 17/086 (2013.01) [B29D 11/00663 (2013.01); B29D 11/00875 (2013.01); G02B 1/10 (2013.01); G02B 6/34 (2013.01); G02B 17/00 (2013.01); G02B 6/30 (2013.01)] | 17 Claims |
1. An apparatus comprising:
(a) a light guiding element having a plurality of faces including first and second parallel faces, said light guiding element being configured for guiding rays of an image by internal reflection at said first and second parallel faces, one of said plurality of faces providing a coupling surface;
(b) a transparent optical element having an interface surface for attachment to said coupling surface, said transparent optical element being configured such that rays of an image propagating within said transparent optical element pass through said interface surface and said coupling surface so as to propagate within the light guiding element;
(c) a non-transparent coating applied to at least part of at least one of said plurality of faces of said light guiding element, said coating defining an edge adjacent to, or overlapping, said coupling surface of said light guiding element,
wherein said coating defines an optical cutoff edge for rays of an image passing from said transparent optical element into said light guiding element, and in that said non-transparent coating is configured to generate internal reflection at an underlying region of said at least one face.
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