Accommodation bifocal optical assembly and optical system including same

Patent metadata

Field	Value
Publication number	US-11567326-B1
Application number	US-202017085654-A
Country	US
Kind code	B1
Filing date	Oct 30, 2020
Priority date	Nov 18, 2019
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

A device includes a light source configured to emit an image light. The device also includes an optical assembly configured to direct the image light to an eye-box of the device. The optical assembly includes a first optical element portion configured to focus a first portion of the image light propagating through the first optical element portion. The optical assembly also includes a second optical element portion configured to focus a second portion of the image light propagating through the second optical element portion. The second optical element portion includes a liquid crystal (“LC”) lens having an adjustable optical power.

First claim

What is claimed is:

1. A device, comprising:
an electronic display configured to emit a first image light and a second image light; and
an optical assembly configured to direct the first image light and the second image light to an eye-box of the device, the optical assembly comprising:
a first optical element portion configured to focus the first image light propagating through the first optical element portion to a first image plane; and
a second optical element portion configured to focus the second image light propagating through the second optical element portion to a second image plane different from the first image plane, the second optical element portion including a liquid crystal (“LC”) lens configured to provide an adjustable optical power,
wherein the second optical element portion is surrounded by and encapsulated in the first optical element portion, and
wherein a first focal length of the first optical element portion is greater than a second focal length of the second optical element portion.

2. The device of claim 1 , wherein the LC lens includes a segmented phase profile (“SPP”) LC lens.

3. The device of claim 2 , wherein the SPP LC lens has a Fresnel structure including a plurality of Fresnel resets that are concentric ring-shaped zones of increasing radii.

4. The device of claim 3 , wherein:
the SPP LC lens includes a plurality of ring electrodes corresponding to the plurality of Fresnel resets, the ring electrodes being concentric and having an identical area, and
a phase difference between adjacent Fresnel resets is substantially the same.

5. The device of claim 4 , wherein:
the ring electrodes are driving electrodes,
the SPP LC lens further includes a plurality of floating electrodes that are discrete and concentric ring electrodes, and are capacitively coupled to the driving electrodes through an insulating layer, and
each floating electrode covers an overlapping area between neighboring driving electrodes.

6. The device of claim 1 , wherein the LC lens includes a plurality of SPP LC lenses stacked together.

7. The device of claim 6 , wherein each SPP LC lens has a Fresnel structure including a plurality of Fresnel resets that are concentric ring-shaped zones of increasing radii.

8. The device of claim 7 , wherein the corresponding Fresnel resets of the plurality of SPP LC lenses are offset by a predetermined distance in a lens plane.

9. The device of claim 6 , wherein the plurality of SPP LC lenses include two stacked SPP LC lenses, with a same configuration and opposite alignment directions.

10. The device of claim 1 , further comprising a controller configured to:
determine a vergence distance of a virtual object represented by the second image light and viewed through the second optical element portion.

11. The device of claim 10 , wherein the controller is further configured to:
determine, based on the determined vergence distance, the optical power of the LC lens; and
control the LC lens to provide the determined optical power to adjust an image distance of the second image plane at which the second image light propagating through the second optical element portion is focused to correspond to the vergence distance.

12. The device of claim 10 , further comprising an eye-tracking device configured to obtain eye-tracking information and to provide the eye-tracking information to the controller.

13. A system, comprising:
an eye-tracking device configured to obtain eye-tracking information; and
an optical assembly comprising:
a first optical element portion configured to focus a first image light propagating through the first optical element portion to a first image plane; and
a second optical element portion configured to focus a second image light propagating through the second optical element portion to a second image plane, the second optical element portion including a liquid crystal (“LC”) lens configured to provide an adjustable optical power adjustable based on the eye-tracking information,
wherein the second optical element portion is surrounded by and encapsulated in the first optical element portion, and
wherein a first focal length of the first optical element portion is greater than a second focal length of the second optical element portion.

14. The system of claim 13 , wherein the LC lens includes a plurality of segmented phase profile (“SPP”) LC lenses stacked together.

15. The system of claim 14 , wherein at least one of the plurality of SPP LC lenses has a Fresnel structure including a plurality of Fresnel resets that are concentric ring-shaped zones of increasing radii.

16. The system of claim 15 , wherein the corresponding Fresnel resets of the plurality of SPP LC lenses are offset by a predetermined distance in a lens plane.

17. The system of claim 15 , wherein:
at least one of the plurality of SPP LC lenses includes a plurality of ring electrodes corresponding to the plurality of Fresnel resets, the ring electrodes being concentric and having an identical area, and
a phase difference between adjacent Fresnel resets is substantially the same.

18. The system of claim 17 , wherein:
the ring electrodes are driving electrodes,
at least one of the plurality of SPP LC lenses further includes a plurality of floating electrodes that are discrete and concentric ring electrodes, and are capacitively coupled to the driving electrodes through an insulating layer, and
at least one of the plurality of floating electrodes covers an overlapping area between neighboring driving electrodes.

19. The device of claim 1 , wherein:
the first image light represents a far virtual object displayed by a first portion of the electronic display, and
the second image light represents a near virtual object displayed by a second portion of the electronic display.

Assignees

• Meta Platforms Tech Llc

Inventors

• Jamali Afsoon
• Zhao Yang
• Wheelwright Brian
• Lanman Douglas Robert
• Zannoli Marina
• Erkelens Ian
• Sulai Yusufu Njoni Bamaxam
• Lu Lu
• Gollier Jacques

Classifications

• G02C2202/20

  Diffractive and Fresnel lenses or lens portions · CPC title

• G02C7/083

  Electrooptic lenses · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02C2202/18

  Cellular lens surfaces · CPC title

• G02F1/13439

  characterised by their electrical, optical, physical properties; materials therefor; method of making · CPC title