Light guide with refractive layer
AssigneeWorld Properties, Inc.
InventorMahyar Vahabzadeh
Life of this patent
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Abstract
A layer having a refractive index less than that of a light guide can be used as a refractive layer, rather than a reflective layer, for increasing light output. The effect is improved if the refractive layer is patterned to correspond to light extracting features on the surface of the light guide. The refractive layer and the light extracting features are on opposed surfaces of the light guide. The refracting layer can be deposited from ink at relatively low cost.
Claims8
A light guide in the form of an edge lit sheet having light extracting features on a first surface characterized in that
- the light guide has an index of refraction, n1;
- a refractive layer overlies a second surface of the light guide;
- the refractive layer has an index of refraction, n2;
- wherein n1>n2>1.
In a hand held electronic device having a back lit user interface, the improvement comprising:
- a back light in the form of an edge lit sheet having an index of refraction, n1, and having light extracting features on a first surface of the sheet;
- a refractive layer overlying a second surface of the sheet;
- wherein the refractive layer has an index of refraction, n2;
- and
- wherein n1>n2>1.
Dependencies are inferred from the claim text.