Asymmetrical light-turning features
AssigneeQUALCOMM MEMS Technologies, Inc.
InventorsZhengwu Li, Shen-Ge Wang, Jian Ma, John Hyunchul Hong
Life of this patent
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Abstract
This disclosure provides systems, methods and apparatus for light-guiding layers including asymmetrical light-turning features. In one aspect, the asymmetrical light-turning features may include a leading edge oriented at an angle which turns light out of the light-guiding layer, and a near-vertical trailing edge which reduces light leakage from the light-guiding layer. In another aspect, the asymmetrical light-turning features of the light-guiding layer may be oriented in the same or similar direction, and may be distributed with decreasing density adjacent a light source to provide more even illumination.
Claims30
A light-turning structure comprising:
- a substrate including a first generally planar surface and a second generally planar surface;
- and
- a plurality of depressions in the shape of asymmetrical frusta formed in the first surface of the substrate, each of the plurality of depressions having an angled sidewall including:
- a leading edge forming a first angle relative to a normal of the first surface and configured to reflect a portion of incident light out of the substrate, and
- a trailing edge forming a second angle relative to the normal of the first surface, wherein the first angle is substantially larger than the second angle.
A reflective display device, comprising:
- an array of reflective display elements;
- and
- a frontlight system configured to illuminate the array of reflective display elements, the frontlight system including:
- a light-guiding layer having a first edge, a first generally planar surface, and a second generally planar surface;
- a light source configured to inject light into the light-guiding layer through the first edge of the light-guiding layer;
- and
- a plurality of light-turning features in the shape of asymmetrical frusta formed in the first surface of the light-guiding layer and configured to reflect light out of the light-guiding layer through the second surface of the light-guiding layer and towards the array of reflective display elements.
A light-turning structure comprising:
- a substrate including a first generally planar surface and a second generally planar surface;
- and
- means for reflecting a portion of incident light out of the substrate, wherein the amount of incident light reflected out of the substrate varies depending on the direction of incidence upon the reflecting means.
A method of fabricating a light-turning structure, comprising:
- embossing a plurality of depressions in the shape of asymmetrical frusta into a first generally planar surface of a substrate, the substrate including a first material having a first index of refraction;
- and
- applying a cladding layer over the first surface of the substrate after embossing the plurality of depressions into the substrate, the cladding layer including a second material having a second index of refraction smaller than the first index of refraction.
Dependencies are inferred from the claim text.