Two-index selectively coated Fresnel
AssigneeFacebook Technologies, LLC
InventorsQi Zhang, Robin Sharma, Andrew John Ouderkirk
Life of this patent
Estimating the term…
Abstract
An optical structure includes a first refractive layer, a Fresnel surface, a dichroic reflective coating, a third refractive layer, and a replica layer. The first refractive layer has a first refractive index. The Fresnel surface is formed in a second refractive layer having a second refractive index. The Fresnel surface includes active surfaces and draft surfaces. The dichroic reflective coating is selectively disposed on the active surfaces. The replica layer is disposed between the Fresnel surface and the third refractive layer. The replica layer has the second refractive index and the second refractive index is higher than the first refractive index.
Claims20
An optical structure comprising:
- a first refractive layer having a first refractive index;
- a Fresnel surface formed in a second refractive layer having a second refractive index, wherein the Fresnel surface includes active surfaces and draft surfaces;
- a dichroic reflective coating selectively disposed on the active surfaces;
- a third refractive layer;
- and
- a replica layer disposed between the Fresnel surface and the third refractive layer, the replica layer having the second refractive index, wherein the second refractive index is higher than the first refractive index.
A head mounted display (HMD) comprising:
- a camera;
- and
- an optical combiner configured to pass visible light to an eyebox area and configured to direct infrared light to the camera, wherein the infrared light is received from the eyebox area, the optical combiner including:
- a first refractive layer having a first refractive index;
- a Fresnel surface formed in a second refractive layer having a second refractive index, wherein the Fresnel surface includes active surfaces and draft surfaces;
- a dichroic reflective coating selectively disposed on the active surfaces;
- a third refractive layer;
- and
- a replica layer disposed between the Fresnel surface and the third refractive layer, the replica layer having the second refractive index, wherein the second refractive index is higher than the first refractive index.
A method of fabricating an optical structure, the method comprising:
- providing a first refractive layer having a first refractive index;
- forming a Fresnel surface in a second refractive layer, wherein the Fresnel surface includes active surfaces and draft surfaces, and wherein the second refractive layer has a second refractive index different than the first refractive index;
- selectively forming a coating on the active surfaces;
- and
- forming a replica layer over the Fresnel surface, wherein the replica layer has the second refractive index, and wherein the replica layer is a negative of the Fresnel surface, the second refractive layer disposed between the first refractive layer and the replica layer.
Dependencies are inferred from the claim text.