Hybrid fresnel lens with increased field of view
A lens defined by a first lens surface and a second lens surface opposite to the first lens surface is disclosed. The lens includes a first portion; and a second portion that is distinct from the first portion and is located around the first portion. The first lens surface for the first portion of the lens is defined by a Fresnel surface profile. The second lens surface for the first portion of the lens is defined by a smooth surface profile. The first lens surface for a second portion of the lens is defined by a Fresnel surface profile. The second lens surface for the second portion of the lens is defined by a Fresnel surface profile.
1. A lens, defined by a first lens surface and a second lens surface opposite to the first lens surface, including:
a first portion; and
a second portion that is distinct from the first portion and is located around the first portion, wherein:
the first lens surface for the first portion of the lens is defined by a Fresnel surface profile;
the second lens surface for the first portion of the lens is defined by a smooth surface profile;
the first lens surface for a second portion of the lens is defined by a Fresnel surface profile;
the second lens surface for the second portion of the lens is defined by a Fresnel surface profile; and
a derivative of the smooth surface profile defining the second lens surface for the first portion of the lens adjacent to a junction between the first portion of the lens and the second portion of the lens is substantially the same as a derivative of the Fresnel surface profile defining the second lens surface for the second portion of the lens adjacent to the junction between the first portion of the lens and the second portion of the lens.
2. The lens of claim 1 , wherein:
the second portion includes an annular region, around the first portion, of the lens.
3. The lens of claim 1 , wherein:
the lens is configured to focus light impinging on the first lens surface.
4. The lens of claim 1 , wherein the first lens surface for the second portion of the lens extends from the first lens surface for the first portion of the lens, and the second lens surface for the second portion of the lens extends from the second lens surface for the first portion of the lens.
5. The lens of claim 1 , wherein:
the second portion of the lens corresponds to one or more portions of a convex-concave lens.
6. The lens of claim 1 , wherein:
the first portion of the lens corresponds to one or more portions of a plano-convex lens.
7. The lens of claim 6 , wherein:
the second portion of the lens corresponds to one or more portions of a convex-concave lens; and
a convex surface of the second portion of the lens extends from a planar surface of the first portion of the lens.
8. The lens of claim 6 , wherein:
the second portion of the lens corresponds to one or more portions of a convex-concave lens; and
a concave surface of the second portion of the lens extends from a planar surface of the first portion of the lens.
9. The lens of claim 1 , wherein:
the first portion of the lens corresponds to one or more portions of a convex-convex lens.
10. The lens of claim 1 , wherein:
the second lens surface is defined by a polynomial that includes a convex surface for the first portion of the lens and a concave surface for the second portion of the lens; and
the first lens surface is defined by a polynomial that includes a convex surface for the first portion of the lens and a convex surface for the second portion of the lens.
11. The lens of claim 1 , wherein:
a width of the first portion is at least 30% of a width of the lens.
12. The lens of claim 1 , wherein:
the second lens surface for the first portion has a first slope adjacent to a junction between the first portion of the lens and the second portion of the lens;
the second lens surface for the second portion has a second slope adjacent to the junction between the first portion of the lens and the second portion of the lens; and
the first slope is substantially the same as the second slope.
13. The lens of claim 1 wherein:
a second derivative of the smooth surface profile defining the second lens surface for the first portion of the lens adjacent to the junction between the first portion of the lens and the second portion of the lens is substantially the same as a second derivative of the Fresnel surface profile defining the second lens surface for the second portion of the lens adjacent to the junction between the first portion of the lens and the second portion of the lens.
14. The lens of claim 1 wherein:
the first lens surface is defined by a single Fresnel surface profile for both the first portion and the second portion of the lens.
15. The lens of claim 1 , wherein:
the first portion and the second portion of the first lens surface are rotationally symmetric.
16. The lens of claim 1 , wherein:
the first portion and the second portion of the first lens surface are reflectionally symmetric without being rotationally symmetric.
17. A display device, comprising:
the lens of claim 1 ; and
an array of light emitting devices coupled with the lens for outputting light through the lens.
18. The display device of claim 17 , wherein the display device is a head-mounted display device.
19. The display device of claim 18 , wherein the array of light emitting devices is configured to output light and transmit the light through the lens toward an eye of a user when the display device is worn on a head of the user.
20. The lens of claim 1 , wherein the Fresnel surface profile defining the second lens surface for the second portion of the lens is configured for causing refraction of light passing through the second lens surface for the second portion of the lens.