Planar holographic optical device for beam expansion and display
AssigneeYeda Research & Devel Co., Ltd.
InventorsYaakov Amitai, Asher Albert Friesem, Isaac Shariv
Life of this patent
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Abstract
A holographic optical device includes a light transmissive substrate carrying first and second laternally separated holographic optical elements. The first holographic optical element diffracts incident light into the substrate where it is trapped by internal reflection so that light impinges more than once at different angles at different locations on at least one of the first and second holographic optical elements with a significantly higher efficiency for one angle of incidence. The second holographic optical element diffracts light out of the substrate. The second holographic optical element may be a display hologram for displaying a three-dimensional image.
Claims22
A holographic optical device comprising:
- a light transmissive substrate;
- a first holographic optical element carried by said substrate;
- and
- a second holographic optical element carried by said substrate laterally of said first holographic optical element;
- wherein said first holographic optical element diffracts incident light into said substrate such that said light is trapped inside by internal reflection;
- and
- wherein said second holographic optical element diffracts said light out of said substrate;
- and
- wherein said light trapped inside said substrate undergoes multiple internal reflections, such that at least part of said light impinges more than once at different locations on at least one of said first and said second holographic optical elements;
- and
- wherein at least part of said light impinges at different angles of incidence on at least one of said different locations;
- and
- wherein said at least one of said first and said second holographic optical elements is constructed such that at said at least one of said different locations, it diffracts said light with significantly higher efficiency for one of said different angles of incidence than for any other angle of incidence.
The device according to claim 30, wherein said first and second holographic optical elements are both holographic lenses.
Dependencies are inferred from the claim text.