Display device with a switchable window and see-through pancake lens assembly

Patent metadata

Field	Value
Publication number	US-10600352-B1
Application number	US-201816209909-A
Country	US
Kind code	B1
Filing date	Dec 4, 2018
Priority date	Dec 4, 2018
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

A display device is configured to be operable in a normal mode that blocks ambient light or a see-through mode that allows ambient light to be visible to a user. The display device includes an emission surface configured to output image light, a switchable window configurable to block ambient light in the normal mode or to transmit ambient light in the see-through mode, and an optical assembly. The optical assembly includes a first region configured to receive image light from the emission surface and to direct the image light toward the eyes of a user. The optical assembly also includes a second region configured to receive ambient light from the switchable window and to allow at least a portion of the ambient light to pass through. A method of setting the display device in normal mode or see-through mode is also disclosed.

First claim

What is claimed is:

1. A display device mountable near an eye of a user and operable in either one of a first mode and a second mode, comprising:
an emission surface configured to output image light;
a switchable window disposed in a periphery of the display device, external to the emission surface, and configurable to block ambient light from outside the display device in the first mode and to transmit ambient light in the second mode;
an optical assembly having a first region configured to receive image light from the emission surface and to direct the image light with a first optical power, and a second region configured to receive the ambient light from the switchable window in the second mode and to allow at least a portion of the received ambient light to pass through with a second optical power distinct from and less than the first optical power.

2. The display device of claim 1 , wherein the second region of the optical assembly is configured to transmit light to the eye of the user with reduced optical aberration compared to the first region of the optical assembly.

3. The display device of claim 1 , wherein the first optical power corresponds to a non-zero focusing power and the second optical power corresponds to a zero focusing power.

4. The display device of claim 1 , wherein the second of the optical assembly is configured to transmit the portion of the received ambient light without change in direction.

5. The display device of claim 1 , wherein
the emission surface has a first edge and a second edge opposite to the first edge;
the switchable window has a first edge and a second edge opposite to the first edge;
the optical assembly has a first edge and a second edge opposite to the first edge,
the first region of the optical assembly is adjacent to the first edge of the optical assembly;
the second region of the optical assembly is adjacent to the second edge of the optical assembly;
the first edge of the switchable window is disposed adjacent to the second edge of the emission surface;
the second edge of the switchable window is disposed adjacent to the second edge of the optical assembly;
the first edge of the optical assembly is disposed proximate to the first edge of the emission surface.

6. The display device of claim 1 , wherein the optical assembly includes a piece of optical material having a first portion in the first region and a second portion in the second region.

7. The display device of claim 1 , wherein the optical assembly includes one or more optical components, and at least one optical component in the optical assembly has a first section in the first region and a second section in the second region.

8. The display device of claim 7 , wherein the at least one optical component has a respective surface that transitions smoothly and continuously from the first region to the second region.

9. The display device of claim 7 , wherein the one or more optical components include:
a beam splitter;
a reflector; and
an optical retarder, wherein
the optical retarder is located between the beam splitter and the reflector,
the first section of the beam splitter is configured to output first image light by transmitting at least a portion of the image light,
the first section of the optical retarder is configured to convert the first image light from a first polarization to a second polarization,
the first section of the reflector is configured to output a second image light by reflecting the first image light having the second polarization towards the optical retarder and beam splitter,
the first section of the optical retarder is further configured to convert the second image light from the second polarization to the first polarization,
the first section of the beam splitter is configured to receive the second image light in the first polarization, and to output a third image light by reflecting at least a portion of the second image light, the third image light having a third polarization that is opposite to the first polarization,
the first section of the optical retarder is further configured to convert the third image light from the third polarization to a fourth polarization that is orthogonal to the second polarization, and
the first section of the reflector is configured to transmit at least a portion of the third image light in the fourth polarization.

10. The display device of claim 9 , wherein
the second section of the beam splitter is configured to transmit at least a first portion of the received ambient light;
the second section of the optical retarder is configured to convert the first portion of the received ambient light from a third polarization a fourth polarization; and
the second section of the reflector is configured to transmit a second portion of the received ambient light having the fourth polarization.

11. The display device of claim 1 , wherein the second region of the optical assembly is configured to transmit at least the portion of the received ambient light to the eye of the user, and
an optical path of the portion of the received ambient light does not include a fold.

12. The display device of claim 1 , wherein the optical assembly is configured to direct at least a portion of the image light from the emission surface to the eye of the user and an optical path of the portion of the image light includes one or more folds.

13. The display device of claim 1 , wherein the switchable window includes one or more polarizers and one or more optical retarders in an optical path of the received ambient light, wherein:
the one or more optical retarders include a switchable optical retarder configured to be in an active state in the first mode and in an inactive state in the second mode;
the switchable window is configured to output at least the portion of the received ambient light, having a third polarization, when the switchable optical retarder is in the inactive state; and
the switchable window is configured to block the ambient light when the switchable optical retarder is in the active state.

14. The display device of claim 1 , wherein the switchable window includes one or more polarizers and one or more optical retarders in an optical path of the received ambient light, wherein
the one or more optical retarders include a switchable optical retarder configured to be in an inactive state in the first mode and in an active state in the second mode
the switchable window is configured to output at least the portion of ambient light, having a third polarization, when the switchable optical retarder is in the active state, and
the switchable window is configured to block the ambient light when the switchable optical retarder is in the inactive state.

15. The display device of claim 1 , wherein:
the switchable window includes one or more polarization volume holograms in an optical path of the received ambient light; and
at least one polarization volume hologram of the one or more polarization volume holograms is switchable between an active state and an inactive state.

16. The display device of claim 15 , wherein the one or more polarization volume holograms include a polarization volume hologram, switchable between the inactive state in the first mode and the active state in the second mode.

17. The display device of claim 15 , wherein the one or more polarization volume holograms include:
a first polarization volume hologram; and
a second polarization volume hologram, wherein
the first polarization volume hologram and the second polarization volume hologram are in the inactive state in

Assignees

• Facebook Tech Llc

Inventors

• Wheelwright Brian
• Gollier Jacques
• Geng Ying
• Sulai Yusufu Njoni Bamaxam
• Peng Fenglin
• Amirsolaimani Babak

Classifications

• G02B5/3025

  Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state (G02B5/3008, G02B5/3016 take precedence) · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B2027/0165

  associated with a head-down display · CPC title

• G06F3/013

  Eye tracking input arrangements (G06F3/015 takes precedence) · CPC title

• G09G2360/144

  the light being ambient light · CPC title