Increasing effective eyebox size of an HMD

• US 9,116,337 B1
• Filed: 03/21/2012
• Issued: 08/25/2015
• Est. Priority Date: 03/21/2012
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Miao, Xiaoyu
• Primary Examiner(s): Perungavoor, Sath V
• Assistant Examiner(s): Nawaz, Talha
• Application Number:
  US13/426,439
• Time in Patent Office: 1,252 Days
• Field of Search: 348 41-161
• US Class Current: 1/1
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/0181 Adaptation to the pilot/driver
• CPC Class Codes: G02B 26/005 based on electrowetting
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 3/12 Fluid-filled or evacuated lenses
• CPC Class Codes: G02B 3/14 of variable focal length

Abstract

An apparatus for a head mounted display includes light bending optics to deliver display light from an image source to a near-to-eye emission surface for emitting the display light to an eye of a user within an eyebox. An eye tracking camera system acquires an image of the eye for tracking movement of the eye. A controller is coupled to the eye tracking camera system to receive image data and to determine a location of the eye based on the image data. The controller is coupled to an eyebox actuator to dynamically adjust the lateral position of the eyebox based upon the location of the eye to extend an effective size of the eyebox from which the eye can view the display light.

Claims

1. An apparatus, comprising:

an image source to generate display light;

light bending optics to deliver the display light from the image source to a near-to-eye emission surface for emitting the display light to an eye of a user within an eyebox;

an eye tracking camera system for acquiring an image of the eye for tracking movement of the eye;

an eyebox actuator for adjusting a lateral position of the eyebox; and

a controller coupled to the eye tracking camera system to receive image data and to determine a location of the eye based on the image data, the controller coupled to the eyebox actuator to control the eyebox actuator to dynamically adjust the lateral position of the eyebox to follow the movement of the eye in real-time such that the eyebox moves laterally when the eye looks left or right to dynamically extend an effective size of the eyebox from which the eye can view the display light,

wherein the light bending optics comprise;

a light relay optically coupled to the image source to receive the display light at a first end; and

an adjustable end reflector disposed at an opposite end of the light relay from the first end coupled to the image source, the adjustable end reflector coupled to receive the display light along a forward propagating path and reflect the display light along a reverse propagating path, wherein the adjustable end reflector is coupled to the eyebox actuator to adjust an angle of the reverse propagating path responsive to the controller.

2. The apparatus of claim 1, wherein the adjustable end reflector comprises:

an end reflector; and

a liquid lens disposed between the end reflector and the light relay through which the forward and reverse propagating paths pass, the liquid lens to control the angle of the reverse propagating path,

wherein the eyebox actuator comprises a voltage controller coupled to apply a voltage across the liquid lens to adjust a shape of the liquid lens in real-time in response to the location of the eye under control of the controller.

3. The apparatus of claim 1, wherein the adjustable end reflector comprises:

an end reflector; and

a gradient refractive index (“

GRIN”

) lens disposed between the end reflector and the light relay through which the forward and reverse propagating paths pass, the GRIN lens to control the angle of the reverse propagating path,

wherein the eyebox actuator further comprises a voltage controller coupled to apply a voltage across the GRIN lens to adjust a lensing characteristic of the GRIN lens in real-time in response to the location of the eye under control of the controller.

4. The apparatus of claim 1, wherein the adjustable end reflector comprises:

an end reflector movably mounted to the light relay to slide relative to the light relay,

wherein the eyebox actuator comprises one of a piezo-electric crystal or a micro-electro-mechanical-systems (“

MEMS”

) actuator to slide the end reflector in real-time in response to the location of the eye under control of the controller.

5. The apparatus of claim 1, wherein the light bending optics further comprise:

an out-coupling beam splitter disposed along the light relay between the image source and the adjustable end reflector, the out-coupling beam splitter to pass at least a portion of display light traveling along the forward propagating path and to reflect at least a portion of the display light traveling along the reverse propagating path out the emission surface,

wherein the out-coupling beam splitter includes two beam splitter portions,

wherein the eyebox actuator further comprises one of a piezo-electric crystal or a micro-electro-mechanical-systems (“

MEMS”

) actuator to slide one of the two beam splitter portions relative to the other beam splitter portion in real-time in response to the location of the eye under control of the controller.

6. The apparatus of claim 1, wherein the light bending optics further comprise:

an out-coupling beam splitter disposed along the light relay between the image source and the adjustable end reflector, the out-coupling beam splitter to pass at least a portion of display light traveling along the forward propagating path and to reflect at least a portion of the display light traveling along the reverse propagating path out the emission surface,

wherein the out-coupling beam splitter is pivotally mounted within the light relay,

wherein the eyebox actuator further comprises one of a piezo-electric crystal or a micro-electro-mechanical-systems (“

MEMS”

) actuator to pivot the out-coupling beam splitter in real-time in response to the location of the eye under control of the controller.

7. The apparatus of claim 6, wherein the beam splitter comprises a polarizing beam splitter and wherein the light bending optics further include a half-wave plate rotator disposed in the forward propagating path of the display light between the out-coupling beam splitter and a quarter-wave plate rotator disposed in the forward and reverse propagating paths between the out-coupling beam splitter and the end reflector.

8. The apparatus of claim 1, wherein the image source comprises:

a lamp source;

a liquid crystal on silicon (“

LCOS”

) display panel positioned to be illuminated by the lamp source and to selectively reflect lamp light as the display light; and

an in-coupling beam splitter positioned adjacent to the LCOS display panel to redirect the display light from the LCOS display panel along a forward propagating path within the light bending optics,

wherein the eyebox actuator further comprises one of a piezo-electric crystal or a micro-electro-mechanical-systems (“

MEMS”

) actuator to slide the LCOS display panel relative to the in-coupling beam splitter in real-time in response to the location of the eye under control of the controller.

9. The apparatus of claim 1, wherein the image source comprises:

a lamp source;

a liquid crystal on silicon (“

LCOS”

) display panel positioned to be illuminated by the lamp source and to selectively reflect lamp light as the display light; and

an in-coupling beam splitter positioned adjacent to the LCOS display panel to redirect the display light from the LCOS display panel along a forward propagating path within the light bending optics,

wherein the eyebox actuator further comprises a video controller that translates a position of a display image produced by the display light in real-time in response to the location of the eye under control of the controller, wherein the display image has fewer pixels than the LCOS display panel such that only a portion of the LCOS display panel is used to generate the display image at a given time.

10. A head mounted display, comprising:

an image source to generate display light;

light bending optics to deliver the display light from the image source to a near-to-eye emission surface for emitting the display light to an eye of a user within an eyebox;

an eye tracking camera system for acquiring an image of the eye for tracking movement of the eye;

an eyebox actuator for adjusting a lateral position of the eyebox;

a controller coupled to the eye tracking camera system to receive image data and to determine a location of the eye based on the image data, the controller coupled to the eyebox actuator to control the eyebox actuator to dynamically adjust the lateral position of the eyebox to follow the movement of the eye in real-time such that the eyebox moves laterally when the eye looks left or right to extend an effective size of the eyebox from which the eye can view the display light; and

a frame assembly to support the image source, the light bending optics, the eye tracking camera system, the eyebox actuator, and the controller for wearing on a head of the user with the emission surface positioned in front of the eye of the user,

wherein the light bending optics comprise;

a light relay optically coupled to the image source to receive the display light at a first end;

an end reflector disposed at an opposite end of the light relay from the first end coupled to the image source, the adjustable end reflector coupled to receive the display light along a forward propagating path and reflect the display light along a reverse propagating path, wherein the adjustable end reflector is coupled to the eyebox actuator to adjust an angle of the reverse propagating path responsive to the controller.

11. The head mounted display of claim 10, wherein the adjustable end reflector comprises:

an end reflector; and

a liquid lens disposed between the end reflector and the light relay through which the forward and reverse propagating paths pass, the liquid lens to control the angle of the reverse propagating path,

wherein the eyebox actuator comprises a voltage controller coupled to apply a voltage across the liquid lens to adjust a shape of the liquid lens in real-time in response to the location of the eye under control of the controller.

12. The head mounted display of claim 10, wherein the adjustable end reflector comprises:

an end reflector; and

a gradient refractive index (“

GRIN”

) lens disposed between the end reflector and the light relay through which the forward and reverse propagating paths pass, the GRIN lens to control the angle of the reverse propagating path,

wherein the eyebox actuator comprises a voltage controller coupled to apply a voltage across the GRIN lens to adjust a lensing characteristic of the GRIN lens in real-time in response to the location of the eye under control of the controller.

13. The head mounted display of claim 10, wherein the adjustable end reflector comprises:

an end reflector movably mounted to the light relay to slide relative to the light relay,

wherein the eyebox actuator comprises one of a piezo-electric crystal or a micro-electro-mechanical-systems (“

MEMS”

) actuator to slide the end reflector in real-time in response to the location of the eye under control of the controller.

14. The head mounted display of claim 10, wherein the light bending optics further comprise:

an out-coupling beam splitter disposed along the light relay between the image source and the end reflector, the out-coupling beam splitter to pass at least a portion of display light traveling along the forward propagating path and to reflect at least a portion of the display light traveling along the reverse propagating path out the emission surface,

wherein the out-coupling beam splitter is pivotally mounted within the light relay,

wherein the eyebox actuator further comprises one of a piezo-electric crystal or a micro-electro-mechanical-systems (“

MEMS”

) actuator to pivot the out-coupling beam splitter in real-time in response to the location of the eye under control of the controller.

15. The head mounted display of claim 10, wherein the image source comprises:

a lamp source;

a liquid crystal on silicon (“

LCOS”

) display panel positioned to be illuminated by the lamp source and to selectively reflect lamp light as the display light; and

an in-coupling beam splitter positioned adjacent to the LCOS display panel to redirect the display light from the LCOS display panel along a forward propagating path within the light bending optics,

wherein the eyebox actuator further comprises one of a piezo-electric crystal or a micro-electro-mechanical-systems (“

MEMS”

) actuator to slide the LCOS display panel relative to the in-coupling beam splitter in real-time in response to the location of the eye under control of the controller.

16. The head mounted display of claim 10, wherein the image source comprises:

a lamp source;

a liquid crystal on silicon (“

LCOS”

) display panel positioned to be illuminated by the lamp source and to selectively reflect lamp light as the display light; and

an in-coupling beam splitter positioned adjacent to the LCOS display panel to redirect the display light from the LCOS display panel along a forward propagating path within the light bending optics,

wherein the eyebox actuator further comprises a video controller that translates a display image produced by the display light in real-time in response to the location of the eye under control of the controller, wherein the display image has fewer pixels than the LCOS display panel such that only a portion of the LCOS display panel is used to generate the display image at a given time.