Focus adjusting virtual reality headset

Patent metadata

Field	Value
Publication number	US-10025060-B2
Application number	US-201514963109-A
Country	US
Kind code	B2
Filing date	Dec 8, 2015
Priority date	Dec 8, 2015
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

A virtual reality headset displays a three-dimensional (3D) virtual scene and includes a varifocal element to dynamically adjust a focal length of an optics block included in the virtual reality headset based on a location in the virtual scene where the user is looking. The headset tracks a user's eyes to approximate gaze lines and determines a plane of focus for a frame of the virtual scene as the intersection of the gaze lines. The varifocal element adjusts the focal length of the optics block so the optics block is focused at the plane of focus, which keeps the user's eyes in a zone of comfort as vergence and accommodation change. Based on the plane of focus, the virtual reality headset may provide depth cues, such as depth of field blur, to planes in the virtual scene deeper in the user's field of view than the plane of focus.

First claim

What is claimed is:

1. A virtual reality (VR) headset comprising:
at least one processor;
an electronic display element configured to display a virtual scene to a user wearing the VR headset;
an optics block configured to direct light from the electronic display element to an exit pupil of the VR headset;
an eye tracking system including an image capturing element, the eye tracking system configured to determine an eye position of each eye of the user and gaze lines for each eye of the user;
memory including instructions that, when executed by the at least one processor, cause the at least one processor to:
determine a vergence depth for the user based on an estimated intersection of the gaze lines for each eye of the user; and

a varifocal actuation block configured to change a focal length of the optics block based at least in part on the vergence depth, wherein the memory, when executed by the at least one processor, further causes the at least one processor to:
determine, for a frame of the virtual scene, a state of the optics block, the state of the optics block corresponding to a combination of a focal length for the determined vergence depth, and the determined eye position of an eye of the user relative to the optics block, each state of the optics block being associated with a distortion correction map of a plurality of distortion correction maps, each distortion correction map corrects for a different combination of:
(1) a first optical error inherent to the optics block and associated with the focal length for the determined vergence depth, and
(2) a second optical error associated with the determined eye position of the eye of the user relative to the optics block;

determine, based on the state of the optics block for the frame, a distortion correction map for the frame of the virtual scene; and
display the frame of the virtual scene on the electronic display element subject to the distortion correction map for the frame of the virtual scene to correct for optical error introduced by the determined state of the optics block for the frame.

2. The VR headset of claim 1 , wherein the varifocal actuation block is configured to change the focal length of the optics block by changing a distance between the optics block and the electronic display element.

3. The VR headset of claim 1 , wherein the varifocal actuation block is configured to change the focal length of the optics block by changing a shape or optical path length of a lens included in the optics block.

4. The VR headset of claim 3 , wherein changing the shape or optical path length of the lens of the optics block includes using at least one selected from a group consisting of: a shape-changing polymer lens, a liquid lens and electrowetting, an Alvarez-Lohmann lens, a deformable membrane mirror, a liquid crystal (electroactive) lens, a phase-only spatial light modulator (SLM), and any combination thereof.

5. The VR headset of claim 1 , further comprising a head position tracking system including one or more position sensors configured to determine a position and an orientation of the VR headset, and wherein the instructions that, when executed by the at least one processor, cause the at least one processor to determine the vergence depth for the user based on the estimated intersection of the gaze lines for each eye of the user cause the at least one processor to:
determine a portion of the virtual scene being viewed by the user based on the position and the orientation of the VR headset; and
generate a filtered vergence depth based on a comparison of the vergence depth to scene geometry data identifying distances within the portion of the virtual scene being viewed by the user.

6. The VR headset of claim 5 , wherein the varifocal actuation block is configured to change the focal length of the optics block based at least in part on the filtered vergence depth.

7. A headset comprising:
at least one processor;
an electronic display configured to display a virtual scene;
an optics block configured to direct light from the electronic display to an exit pupil of the VR headset;
an eye tracking system configured to determine an eye position for each eye of a user, gaze lines for each eye of the user, and a vergence depth corresponding to an intersection of the gaze lines; and
a varifocal actuation block configured to change a focal length of the optics block based at least in part on the vergence depth, wherein the memory, when executed by the at least one processor, further causes the at least one processor to:
determine, for a frame of the virtual scene, a state of the optics block, the state of the optics block corresponding to a combination of a focal length for the determined vergence depth, and the determined eye position of an eye of the user relative to the optics block, each state of the optics block being associated with a distortion correction map of a plurality of distortion correction maps, each distortion correction map corrects for a different combination of:
(1) a first optical error inherent to the optics block and associated with the focal length for the determined vergence depth, and
(2) a second optical error associated with the determined eye position of the eye of the user relative to the optics block;

determine, based on the state of the optics block for the frame, a distortion correction map for the frame of the virtual scene; and
display the frame of the virtual scene on the electronic display element subject to the distortion correction map for the frame of the virtual scene to correct for optical error introduced by the determined state of the optics block for the frame.

8. The headset of claim 7 , further comprising:
a head position tracking system including one or more position sensors configured to determine a position and an orientation of the VR headset; and
a memory including instructions that, when executed by the at least one processor, cause the at least one processor to:
determine a portion of the virtual scene being viewed by the user based on the position and the orientation of the VR headset; and
generate a filtered vergence depth based on a comparison of the vergence depth to scene geometry data identifying distances within the portion of the virtual scene being viewed by the user.

9. The headset of claim 8 , wherein the varifocal actuation block is configured to change the focal length of the optics block based at least in part on the filtered vergence depth.

10. The headset of claim 8 , wherein the memory including the instructions that, when executed by the at least one processor, further causes the at least one processor to:
determine, for the determined eye position of each eye, at least one of a distance between each eye and the optics block or a position of each eye relative to the optics block,
wherein each state of the optics block is associated with a focal length of the optics block and at least one of the distance between each eye and the optics block or the position of each eye relative to the optics block, and
wherein each distortion correction map further corrects for optical error introduced by at least one of the distance between each eye and the optics block or the position of each eye relative to the optics block.

11. The headset of claim 7 , wherein the varifocal actuation block is configured to change the focal length of the optics block by changing a distance between the optics block and the electronic display.

12. The headset of claim 7 , wherein the varifocal actuation block is configured to change the focal length of the optics block by changing a shape or optical path length of a lens included in the optics block

Assignees

• Oculus Vr Llc

Inventors

• Lanman Douglas Robert
• Ebert Ryan Michael
• Fix Alexander Jobe
• Nicholls William Aaron
• Mounier Michael Sean
• Cavin Robert Dale

Classifications

• G02B7/287 Primary

  including a sight line detecting device · CPC title

• G06F3/011

  Arrangements for interaction with the human body, e.g. for user immersion in virtual reality (blind teaching G09B21/00) · CPC title

• G06T19/006

  Mixed reality (object pose determination, tracking or camera calibration for mixed reality G06T7/00) · CPC title

• G06F3/013 Primary

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

• G02B2027/0134

  of stereoscopic type · CPC title