Adding prescriptive correction to eyepieces for see-through head wearable displays

• US 10,146,054 B2
• Filed: 07/06/2015
• Issued: 12/04/2018
• Est. Priority Date: 07/06/2015
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google LLC (Alphabet Inc.)
• Inventors: Martinez, Oscar A., Cakmakci, Ozan
• Primary Examiner(s): Allen, Stephone B
• Assistant Examiner(s): FISSEL, TRAVIS S
• Application Number:
  US14/792,084
• Publication Number:
  US 20170010465A1
• Time in Patent Office: 1,247 Days
• Field of Search: 359630, 359631, 359632, 359633, 345632
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 2027/0194 with combiner of laminated type, for optical or mechanical aspects
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: G02C 11/10 Electronic devices other than hearing aids
• CPC Class Codes: G02C 7/02 Lenses; Lens systems ; Methods of designing lenses

Abstract

An eyepiece for a head wearable display includes a curved lightguide component, a curved see-through component, an output coupler, and a prescription layer. The curved lightguide component guides display light received at an input region and releases the display light along an eye-ward direction in a viewing region. The output coupler is disposed at the viewing region to redirect the display light towards the eye-ward direction for output from the curved lightguide component. The output coupler is at least partially transmissive to ambient light incident through a world-facing side such that the viewing region is see-through. The curved see-through component is mated to the world-facing side of the curved lightguide component. The prescription layer has a first side mated to an eye-facing side of the curved lightguide component and a second side having a curvature that introduces prescriptive lensing to both the ambient light and the display light.

Claims

1. An eyepiece for a head wearable display, the eyepiece comprising:

a curved lightguide component for guiding display light received at an input region peripherally located from a viewing region and releasing the display light along an eye-ward direction in the viewing region, the curved lightguide component having an eye-facing side and a world-facing side, wherein the curved lightguide component has a thick portion that extends across a part of the eyepiece then transitions to a thin portion that extends across a remainder of the eyepiece, wherein the thick portion and the thin portion are of constant width along a chord line extending from an input coupler to an output coupler for at least a non-zero distance, and wherein the curved lightguide component extends across the eyepiece;

the output coupler disposed where the thick portion of the curved lightguide component transitions to the thin portion of the curved lightguide component to redirect the display light towards the eye-ward direction for output from the curved lightguide component, wherein the output coupler is at least partially transmissive to ambient light incident through the world-facing side such that the viewing region is see-through;

a curved see-through component mated to the world-facing side of the curved lightguide component; and

a prescription layer having a first side and a second side, wherein the first side is mated to the eye-facing side of the curved lightguide component and the second side has a curvature that introduces prescriptive lensing to both the ambient light and the display light exiting the eyepiece in the viewing region.

2. The eyepiece of claim 1, further comprising:

a first adhesive layer disposed between the prescription layer and the curved lightguide component to form a conformal bond that extends across both the thick and thin portions of the curved lightguide component, wherein the first adhesive layer has a first refractive index that is lower than a second refractive index of the curved lightguide component such that the display light is guided by total internal reflection (“

TIR”

) from the input region to the viewing region along an interface between the first adhesive layer and the curved lightguide component.

3. The eyepiece of claim 2, further comprising:

a second adhesive layer disposed between the curved lightguide component and the curved see-through component, the second adhesive layer having the first refractive index that is lower than the second refractive index,

wherein the display light is guided between the input region and the output coupler entirely by TIR.

4. The eyepiece of claim 1, further comprising:

a first angularly selective coating disposed between the first side of the prescription layer and the eye-facing side of the curved lightguide to guide the display light from the input region to the viewing region along a first interface between the prescription layer and the curved lightguide component; and

a second angularly selective coating disposed along a second interface between the world-facing side of the curved lightguide component and the curved see-through component to guide the display light from the input region to the viewing region along the second interface.

5. The eyepiece of claim 1, wherein a second refractive index of the curved lightguide component is substantially equivalent to a third refractive index of the curved see-through component.

6. The eyepiece of claim 5, wherein a combination of the curved lightguide component and the curved see-through component does not introduce optical power to the ambient light passing through the viewing region of the eyepiece while the prescription layer does introduce the prescriptive lensing to the ambient light passing through the viewing region.

7. The eyepiece of claim 1, wherein the curved see-through component has a thin portion and a thick portion, wherein the thin portion of the curved see-through component conformably mates to the thick portion of the curved lightguide component and wherein the thin portion of the curved lightguide component conformably mates to the thick portion of the curved see-through component, and wherein the output coupler is disposed at a transition from the thick portions to the thin portions at an interface between the curved see-through component and the curved lightguide component.

8. The eyepiece of claim 1, wherein the output coupler comprises one of a freeform partially reflective surface, a diffraction grating, an array of prism structures, a hologram, or a plurality of partially reflective mirror segments.

9. The eyepiece of claim 1, further comprising:

an input coupler disposed at the input region to couple the display light into the curved lightguide component, wherein the input coupler is arranged in the thick portion of the curved lightguide component.

10. The eyepiece of claim 1, wherein the curved see-through component and the prescription layer extend over the entire area of the eyepiece without forming any seams in a middle portion of the eyepiece.

11. The eyepiece of claim 1, wherein a combination of the eye-facing side of the curved lightguide, the world-facing side of the curved lightguide, an input coupler of the curved lightguide, and the output coupler provide lensing power to the display light.

12. A head wearable display, comprising:

a display source to generate display light at a peripheral location;

an eyeglass lens including;

a curved lightguide component for guiding the display light received at an input region peripherally located from a viewing region and releasing the display light along an eye-ward direction in the viewing region, the curved lightguide component having an eye-facing side and a world-facing side, wherein the curved lightguide component has a thick portion that transitions to a thin portion, and wherein the thick portion and the thin portion are of constant width along a chord line extending from an input coupler to an output coupler for at least a non-zero distance, and wherein the curved lightguide component extends across the eyepiece;

the output coupler disposed at the viewing region to redirect the display light towards the eye-ward direction for output from the curved lightguide component, wherein the output coupler is at least partially transmissive to ambient light incident through the world-facing side such that the viewing region is see-through;

a curved see-through component mated to the world-facing side of the curved lightguide component, wherein the curved see-through component has a thick portion that transitions to a thin portion, and wherein the see-through component extends across the eyepiece,

wherein the thick portion of the curved lightguide component is arranged to comformably mate with the thin portion of the curved see-through component, and wherein the thin portion of the curved lightguide component is arranged to comformably mate with the thick portion of the curved see-through component, and

wherein the output coupler is disposed where the thick portion of the curved lightguide component transitions to the thin portion of the curved lightguide component;

a prescription layer having a first side and a second side, wherein the first side is mated to the eye-facing side of the curved lightguide component and the second side has a curvature that introduces prescriptive lensing to both the ambient light and the display light exiting the eyeglass lens in the viewing region; and

a frame assembly to support the eyeglass lens and the display source for wearing on a head of a user with the viewing region positioned in front of an eye of the user.

13. The head wearable display of claim 12, wherein the eyeglass lens further comprises:

a first adhesive layer disposed between the prescription layer and the curved lightguide component to form a conformal bond, wherein the first adhesive layer has a first refractive index that is lower than a second refractive index of the curved lightguide component such that the display light is guided by total internal reflection (“

TIR”

) from the input region to the viewing region along an interface between the first adhesive layer and the curved lightguide component.

14. The head wearable display of claim 13, wherein the eyeglass lens further comprises:

a second adhesive layer disposed between the curved lightguide component and the curved see-through component, the second adhesive layer having the first refractive index that is lower than the second refractive index,

wherein the display light is guided between the input region and the output coupler entirely by TIR.

15. The head wearable display of claim 12, wherein the eyeglass lens further comprises:

a first angularly selective coating disposed between the first side of the prescription layer and the eye-facing side of the curved lightguide to guide the display light from the input region to the viewing region along a first interface between the prescription layer and the curved lightguide component; and

a second angularly selective coating disposed along a second interface between the world-facing side of the curved lightguide component and the curved see-through component to guide the display light from the input region to the viewing region along the second interface.

16. The head wearable display of claim 12, wherein a combination of the curved lightguide component and the curved see-through component do not introduce optical power to the ambient light passing through the viewing region of the eyeglass lens while the prescription layer does introduce the prescriptive lensing to the ambient light passing through the viewing region.

17. An eyepiece for a head wearable display, the eyepiece comprising:

a curved lightguide component for guiding display light received at an input region peripherally located from a viewing region and emitting the display light along an eye-ward direction in the viewing region, the curved lightguide component having an eye-facing side and a world-facing side, wherein the curved lightguide component has a thick portion that transitions to a thin portion, and wherein the thick portion and the thin portion are of constant width along a chord line extending from and input coupler to an output coupler for at least a non-zero distance, and wherein the curved lightguide component extends across the eyepiece, wherein the viewing region is arranged where the thick portion transitions to the thin portion, and wherein the display light is guided from the input region to the viewing region in the thick portion of the curved lightguide component;

the output coupler disposed where the thick portion of the curved lightguide component transitions to the thin portion of the curved lightguide component to redirect the display light towards the eye-ward direction for output from the curved lightguide component, wherein the output coupler is at least partially transmissive to ambient light incident through the world-facing side such that the viewing region is see-through, wherein the output coupler is disposed where the thick portion of the curved lightguide component transitions to the thin portion of the curved lightguide component; and

a curved see-through component having a first side and a second side, wherein the first side is mated to the world-facing side of the curved lightguide component, wherein the curved see-through component has a thick portion that transitions to a thin portion, and wherein the see-through component extends across the eyepiece,

wherein the thick portion of the curved lightguide component is arranged to comformably mate with the thin portion of the curved see-through component, and wherein the thin portion of the curved lightguide component is arranged to comformably mate with the thick portion of the curved see-through component, and

wherein one of the second side of the curved see-through component or the eye-facing side of the curved lightguide component has a prescriptive curvature that introduces prescriptive lensing.

18. The eyepiece of claim 17, further comprising:

an adhesive layer disposed between the curved lightguide component and the curved see-through component to form a conformal bond, wherein the adhesive layer has a first refractive index that is lower than a second refractive index of the curved lightguide component such that the display light is guided by total internal reflection (“

TIR”

) from the input region to the viewing region along an interface between the adhesive layer and the curved lightguide component.

19. The eyepiece of claim 17, further comprising:

a first angularly selective coating disposed between the curved lightguide component and the curved see-through component to guide the display light from the input region to the viewing region; and

a second angularly selective coating disposed along the eye-facing side of the curved lightguide component to guide the display light from the input region to the viewing region.

20. The eyepiece of claim 17, wherein only the second side of the curved see-through component has the prescriptive curvature that introduces prescriptive lensing to just the ambient light passing through the eyepiece without introducing prescriptive lensing to the display light emitted from the eyepiece.