Off-axis focusing geometric phase lens and system including the same

Patent metadata

Field	Value
Publication number	US-2022107517-A1
Application number	US-202017063710-A
Country	US
Kind code	A1
Filing date	Oct 5, 2020
Priority date	Oct 5, 2020
Publication date	Apr 7, 2022
Grant date	—

Abstract

A lens is provided. The lens includes an optically anisotropic film. The optically anisotropic film has an optic axis configured with an in-plane rotation in at least two opposite in-plane directions from a lens pattern center to opposite lens peripheries. The optic axis rotates in a same rotation direction from the lens pattern center to the opposite lens peripheries. An azimuthal angle changing rate of the optic axis is configured to increase from the lens pattern center to the opposite lens peripheries in at least a portion of the lens including the lens pattern center. The lens pattern center is shifted from a geometry center of the lens by a predetermined distance in a predetermined direction.

First claim

What is claimed is:

1 . A lens, comprising:
an optically anisotropic film having an optic axis configured with an in-plane rotation in at least two opposite in-plane directions from a lens pattern center to opposite lens peripheries, wherein the optic axis rotates in a same rotation direction from the lens pattern center to the opposite lens peripheries, wherein an azimuthal angle changing rate of the optic axis is configured to increase from the lens pattern center to the opposite lens peripheries in at least a portion of the lens including the lens pattern center, and wherein the lens pattern center is shifted from a geometry center of the lens by a predetermined distance in a predetermined direction.

2 . The lens of claim 1 , wherein the portion of the lens including the lens pattern center is substantially the entire lens.

3 . The lens of claim 1 , wherein the portion of the lens including the lens pattern center is a portion less than the entire lens.

4 . The lens of claim 1 , wherein the lens is polarization selective and is switchable between a focusing state and a defocusing state via a polarization switch coupled to the lens.

5 . The lens of claim 1 , wherein a phase shift experienced by a light with a wavelength λ incident onto the lens in at least the portion of the lens including the lens pattern center is

Γ
≈

π
⁢

⁢

r
2

L
⁢
λ

-

2
⁢
π

λ

⁢
K
*
x

,

where K is a non-zero coefficient, r is a distance from the lens pattern center to a local point of the lens, L is a distance between a lens plane and a focal plane of the lens, and x is a coordinate in the predetermined direction of the predetermined shift of the lens pattern center with respect to the geometry center.

6 . The lens of claim 1 , wherein the optically anisotropic film includes at least one of active liquid crystals, reactive mesogens, a liquid crystal polymer, or an amorphous polymer.

7 . The lens of claim 1 , wherein the at least two opposite in-plane directions are radial directions passing the lens pattern center of the lens.

8 . The lens of claim 1 , wherein the at least two opposite in-plane directions are lateral directions passing the lens pattern center of the lens.

9 . The lens of claim 1 , wherein the lens pattern center is a point at which the azimuthal angle changing rate of the optic axis of the optically anisotropic film is the smallest in at least the portion of the lens including the lens pattern center.

10 . The lens of claim 1 , wherein the lens is an off-axis focusing Pancharatnam-Berry phase (“PBP”) lens, and the lens pattern center of the off-axis focusing PBP lens is a symmetry center of a lens pattern of a corresponding on-axis focusing PBP lens.

11 . A system, comprising:
an optical combiner; and a display assembly including:
a light source configured to emit a light;
a lens configured to deflect the light, the lens including:
an optically anisotropic film having an optic axis configured with an in-plane rotation in at least two opposite in-plane directions from a lens pattern center to opposite lens peripheries,
wherein the optic axis rotates in a same rotation direction from the lens pattern center to the opposite lens peripheries,
wherein an azimuthal angle changing rate of the optic axis is configured to increase from the lens pattern center to the opposite lens peripheries in at least a portion of the lens including the lens pattern center and
wherein the lens pattern center is shifted from a geometry center of the lens by a predetermined distance in a predetermined direction; and

a beam steering device configured to steer the light received from the lens toward the optical combiner,
wherein the optical combiner is configured to direct the light received from the beam steering device to an eye-box of the system.

12 . The system of claim 11 , wherein a phase shift experienced by the light incident onto the lens with a wavelength λ in at least the portion of the lens including the lens pattern center is

Γ
≈

π
⁢

⁢

r
2

L
⁢
λ

-

2
⁢
π

λ

⁢
K
*
x

,

where K is a non-zero coefficient, r is a distance from the lens pattern to a local point of the lens, L is a distance between a lens plane and a focal plane of the lens, and x is a coordinate in the predetermined direction of the predetermined shift of the lens pattern center with respect to the geometry center.

13 . The system of claim 11 , wherein the lens is configured to convert an on-axis diverging light emitted from the light source into an off-axis collimated light.

14 . The system of claim 11 , wherein the optically anisotropic film includes at least one of active liquid crystals, reactive mesogens, a liquid crystal polymer, or an amorphous polymer.

15 . The system of claim 11 , wherein the at least two opposite in-plane directions are radial directions or lateral directions of the lens.

16 . The system of claim 11 , wherein the light source includes at least one of a laser diode or a vertical cavity surface emitting laser.

17 . A system, comprising:
a light source configured to emit a light; a lens configured to deflect the light to illuminate an object, the lens including:
an optically anisotropic film having an optic axis configured with an in-plane rotation in at least two opposite in-plane directions from a lens pattern center to opposite lens peripheries of the lens,
wherein the optic axis rotates in a same rotation direction from the lens pattern center to the opposite lens peripheries,
wherein an azimuthal angle changing rate of the optic axis is configured to increase from the lens pattern center to the opposit

Assignees

• Facebook Tech Llc

Inventors

• Yaroshchuk Oleg
• Lam Wai Sze Tiffany
• Lee Yun-Han
• Parsons Maxwell
• Ouderkirk Andrew John
• Lu Lu
• McEldowney Scott Charles

Classifications

• G02B27/0977

  Reflective elements · CPC title

• G02B27/0955

  Lenses (lenses per se G02B3/00) · CPC title

• G02B27/28

  for polarising (used in stereoscopes G02B30/25) · CPC title

• G02B26/0875

  by means of one or more refracting elements · CPC title

• G02F2203/62

  Switchable arrangements whereby the element being usually not switchable · CPC title