Near focus corrective AR glasses
A head-mounted display for an augmented reality application includes an image light guide arranged within the aperture of an eye rim section of the head-mounted display for directing angularly related image-bearing light beams encoding a virtual object toward an eyebox for the viewing the virtual object at a hyperfocal to near infinite focusing distance to the eyebox. A negative-power optic between one side of the image light guide and the eyebox diverges the image-bearing beams in advance of the eyebox for viewing the virtual object at a closer distance to the eyebox that is less than the hyperfocal distance. A positive-power optic on an opposite side of the image light guide compensates for the negative-power of the negative-power optic for viewing a real-world object at its actual distance to the eyebox. A corrective optic located between the image light guide and the eyebox reduces the viewer's aberrations for viewing of both the real-world object and the virtual object.
1 . A head-mounted display, comprising:
a temple;
an eye rim section having an aperture, wherein the eye rim section is coupled with the temple, and wherein a real-world object within an ambient environment is viewable through the aperture;
a nose bridge coupled with the eye rim section;
an image light guide fixedly arranged at least partially within the aperture of the eye rim section, the image light guide including:
a transmissive planar waveguide having plane-parallel inner and outer surfaces,
an in-coupling optic operable to direct angularly related image-bearing light beams encoding a virtual object into the waveguide from an image source, wherein the image-bearing light beams propagate by total internal reflection, and
an out-coupling optic comprising a diffraction grating configured to expand at least one dimension of an eyebox and operable to direct the propagating image-bearing light beams from the waveguide toward the eyebox, wherein the virtual object is viewed at a first focusing distance from the eyebox;
a multifunction optic arranged at least partially within the aperture between the inner surface of the waveguide and the eyebox, wherein the multifunction optic is formed as a single optical element operable to provide:
(a) a negative optical power contribution operable to diverge the image-bearing light beams in advance of the eyebox, wherein the virtual object is operable to be viewed at a second focusing distance from the eyebox and the second focusing distance is closer than the first focusing distance, and
(b) a corrective optical contribution operable to reduce optical aberrations associated with viewing both the real-world object and the virtual object at the second focusing distance, wherein the corrective optical contribution includes a cylindrical optical power contribution; and
a positive-power optic arranged at least partially within the aperture between the outer surface of the waveguide and the ambient environment, wherein the positive-power optic is operable to compensate for the negative optical power contribution of the multifunction optic without compensating for the corrective optical contribution of the multifunction optic, wherein the real-world object is viewed at its actual distance from the eyebox with corrected vision;
a removable lens-holder configured to support the multifunction optic and the positive-power optic at least partially within the aperture of the eye rim section, wherein the lens-holder comprises a housing configured to engage an outer periphery of the multifunction optic and an outer periphery of the positive-power optic, and a slot configured to accommodate the image light guide at least partially between the positive-power optic and the multifunction optic,
wherein the lens-holder is slideably removeable from the eye rim section and the image light guide,
wherein the temple and the nose bridge each comprise a slot configured to slideably receive the lens holder via a friction fit.
2 . The head-mounted display of claim 1 , wherein the multifunction optic is a single refractive lens element.
3 . The head-mounted display of claim 1 , wherein the first focusing distance is a hyperfocal to near infinite distance and the closer second focusing distance is between 0.05 meters and 1.50 meters.
4 . The head-mounted display of claim 1 , wherein the multifunction optic is a first of a plurality of multifunction optics, and the first multifunction optic is removable and replaceable with a second of the multifunction optics to adapt the display to a different optical prescription, wherein the lens-holder is slideably removeable from the head-mounted display.
5 . The head-mounted display of claim 1 , wherein the multifunction optic is a first of a plurality of multifunction optics, the positive-power optic is a first of a plurality of positive-power optics, and the first multifunction optic and the first positive-power optic are collectively removable and replaceable with a second of the multifunction optics and a second of the positive-power optics for changing the closer second focusing distance to a different third focusing distance.
6 . The head-mounted display of claim 1 , further comprising a transmissive protective outer cover arranged at least partially within the aperture between the positive-power optic and the ambient environment.
7 . The head-mounted display of claim 1 , wherein the positive-power optic is a lens having a convex outer surface facing the ambient environment and is treated with a protective coating.
8 . The head-mounted display of claim 1 , wherein the image light guide is in fixed arrangement at least partially within the aperture.
9 . An augmented reality virtual image display system for managing a viewer's view of a virtual object and a real-world object within a common field of view, comprising:
a temple;
an eye rim section having an aperture, wherein the eye rim section is coupled with the temple; and
a nose bridge coupled with the eye rim section;
an image light guide including inner and outer surfaces fixedly arranged at least partially within the aperture of the eye rim section, comprising:
an in-coupling optic operable to direct angularly related image-bearing light beams encoding a virtual object into the waveguide from an image source, wherein the image-bearing light beams propagate by total internal reflection, and
an out-coupling optic comprising a diffraction grating configured to expand at least one dimension of an eyebox,
wherein the image light guide is operable to direct angularly related image-bearing light beams encoding the virtual object toward the eyebox, wherein the virtual object is viewed at a first focusing distance from the eyebox;
a multifunction optic located between the inner surface of the image light guide and the eyebox, wherein the multifunction optic is formed as a single optical element operable to provide:
(a) a negative optical power contribution operable to diverge the image-bearing light beams in advance of the eyebox, wherein the virtual object is viewed at a second focusing distance from the eyebox and the second focusing distance is closer than the first focusing distance, and
(b) a corrective optical contribution operable to reduce optical aberrations associated with viewing of both the real-world object and the virtual object at the second focusing distance, wherein the corrective optical contribution includes a cylindrical optical power contribution; and
a positive-power optic arranged adjacent to the outer surface of the image light guide, wherein the positive-power optic is operable to compensate for the negative optical power contribution of the multifunction optic without compensating for the corrective optical contribution of the multifunction optic, wherein the real-world object is viewed at its actual distance from the eyebox with corrected vision;
a lens-holder configured to support the multifunction optic and the positive-power optic at least partially within the aperture of the eye rim section, wherein the lens-holder comprises a housing engaged with an outer periphery of the multifunction optic and an outer periphery of the positive-power optic,
wherein the lens-holder is slideably removeable from the augmented reality virtual image display system and the image light guide, and wherein the lens-holder comprises a slot configured to accommodate the image light guide at least partially between the positive-power optic and the multifunction optic,
wherein the temple and the nose bridge each comprise a slot configured to slideably receive the lens holder via a friction fit.
10 . The augmented reality virtual image display system of claim 9 , wherein the multifunction optic is a single refractive lens element.
11 . The augmented reality virtual image display system of claim 9 , wherein the first focusing distance is a hyperfocal to near infinite distance and the closer second focusing distance is less than the hyperfocal distance.
12 . The augmented reality virtual image display system of claim 11 , wherein the closer second focusing distance is between 1.5 meters and 4 meters.
13 . The augmented reality virtual image display system of claim 11 , wherein the closer second focusing distance is between .05 meters and 1.5 meters.
14 . The augmented reality virtual image display system of claim 11 , wherein the corrective optical contribution is set for reducing the optical aberrations at the closer second focusing distance.
15 . The augmented reality virtual image display system of claim 9 , wherein the multifunction optic is a first of a plurality of multifunction optics, and the first multifunction optic is removable and replaceable with a second of the multifunction optics to adapt the display system to a different optical prescription.
16 . The augmented reality virtual image display system of claim 15 , wherein a negative-power contribution of the second multifunction optic is the same as the negative power contribution of the first multifunction optic, and a corrective optical contribution of the second multifunction optic is different from the corrective optical contribution of the first multifunction optic.
17 . The augmented reality virtual image display system of claim 9 , wherein the multifunction optic is a first of a plurality of multifunction optics, the positive-power optic is a first of a plurality of positive-power optics, and the first multifunction optic and the first positive-power optic are collectively removable and replaceable with a second of the multifunction optics and a second of the positive-power optics for changing the closer second focusing distance to a different third focusing distance.
18 . The augmented reality virtual image display system of claim 17 , wherein the second multifunction optic provides a corrective optical contribution to reduce the optical aberrations at the different third focusing distance.
19 . The augmented reality virtual image display system of claim 9 , further comprising a transmissive protective outer cover located between the positive-power optic and an ambient environment from which the real-world object is viewed.
20 . The augmented reality virtual image display system of claim 9 , wherein the positive-power optic is a lens having a convex outer surface that faces an ambient environment from which the real-world object is viewed and that is treated with a protective coating.
21 . The augmented reality virtual image display system of claim 9 , wherein the image light guide includes a transmissive planar waveguide having plane-parallel inner and outer surfaces, an in-coupling optic for directing the angularly related image-bearing light beams into the waveguide from an image source for propagation by internal reflection from the inner and outer surfaces, and an out-coupling optic for directing the propagating image-bearing light beams from the waveguide toward the eyebox; wherein the image light guide is in fixed arrangement with the head-mounted display.
22 . The augmented reality virtual image display system of claim 9 , further comprising a gasket configured to secure the lens holder to the eye rim section.
23 . The augmented reality virtual image display system of claim 9 , wherein the lens holder is operable to slide in a plane substantially parallel with the inner and outer surfaces of the image light guide.