Augmented reality display having multi-element adaptive lens for changing depth planes
In some embodiments, an augmented reality system includes at least one waveguide that is configured to receive and redirect light toward a user, and is further configured to allow ambient light from an environment of the user to pass therethrough toward the user. The augmented reality system also includes a first adaptive lens assembly positioned between the at least one waveguide and the environment, a second adaptive lens assembly positioned between the at least one waveguide and the user, and at least one processor operatively coupled to the first and second adaptive lens assemblies. Each lens assembly of the augmented reality system is selectively switchable between at least two different states in which the respective lens assembly is configured to impart at least two different optical powers to light passing therethrough, respectively. The at least one processor is configured to cause the first and second adaptive lens assemblies to synchronously switch between different states in a manner such that the first and second adaptive lens assemblies impart a substantially constant net optical power to ambient light from the environment passing therethrough.
1. A display device comprising:
a waveguide assembly comprising a waveguide configured to output outcoupled light along an output surface of the waveguide; and
a first adaptive lens assembly having a first major surface facing the output surface, the first adaptive lens assembly comprising:
a first waveplate lens;
a second waveplate lens; and
a first switchable waveplate interposed between the first waveplate lens and the second waveplate lens, wherein the switchable waveplate is selectively switchable between:
a first state configured to pass the outcoupled light without altering a polarization state of the outcoupled light; and
a second state configured to alter the polarization state of the outcoupled light passing therethrough; and
a second adaptive lens assembly having a second major surface facing an external scene opposite the output surface, and a second minor surface facing the first major surface, the second adaptive lens assembly comprising:
a third waveplate lens;
a fourth waveplate lens; and
a second switchable waveplate interposed between the third waveplate lens and the fourth waveplate lens, wherein the second switchable waveplate is selectively switchable between:
a third state configured to pass light from the external scene without altering a polarization state of the light from the external scene; and
a fourth state configured to alter the polarization state of the light from the external scene passing therethrough.
2. The display device of claim 1 , wherein each of the first and second waveplate lenses is configured to alter a polarization state of the outcoupled light passing therethrough, and to converge or diverge the outcoupled light.
3. The display device of claim 2 , wherein each of the third and fourth waveplate lenses is configured to alter a polarization state of the light from the external scene passing therethrough, and to converge or diverge the outcoupled light.
4. The display device of claim 1 , further comprising one or more polarization selective turning elements positioned to be disposed between the waveguide assembly and a user upon wearing of the augmented reality system by the user, wherein the first waveplate lens is positioned to be closer to the user than the second waveplate lens.
5. The display device of claim 4 , wherein the one or more polarization selective turning elements includes a first polarization selective turning element positioned to be disposed between the user and the first waveplate lens upon wearing of the augmented reality system by the user.
6. The display device of claim 4 , wherein the one or more polarization selective turning elements includes a second polarization selective turning element disposed between the waveguide assembly and the second waveplate lens.
7. The display device of claim 4 , wherein the one or more polarization selective turning elements include one or more of a polarization grating, a diffractive optical element, and/or a holographic optical element.
8. The display device of claim 1 , further comprising one or more polarization selective turning elements disposed between the waveguide assembly and the external scene, wherein the third waveplate lens is closer to the external scene than the fourth waveplate lens.
9. The display device of claim 8 , wherein the one or more polarization selective turning elements includes a third polarization selective turning element disposed between the external scene and the third waveplate lens.
10. The display device of claim 8 , wherein the one or more polarization selective turning elements includes a fourth polarization selective turning element disposed between the waveguide assembly and the fourth waveplate lens.
11. The display device of claim 8 , wherein the one or more polarization selective turning elements include one or more of a polarization grating, a diffractive optical element, and/or a holographic optical element.
12. An adaptive lens assembly comprising:
one or more waveplate lenses and one or more switchable waveplates aligned in an optical path,
wherein each of the one or more waveplate lenses is configured to alter a polarization state of light passing therethrough, to provide a first optical power for light having a first polarization, and to provide a second optical power for light having a second polarization, and
wherein each of the one or more switchable waveplates is selectively switchable between:
a first state configured to pass the light therethrough without altering a polarization state of the light; and
a second state configured to alter the polarization state of the light passing therethrough.
13. The adaptive lens assembly of claim 12 , wherein one or both of the waveplate lenses and the switchable waveplates comprise liquid crystals.
14. The adaptive lens assembly of claim 12 , wherein each of the one or more switchable waveplates in the second state is a switchable half waveplate configured to invert a handedness of circularly polarized light when activated.
15. The adaptive lens assembly of claim 12 , wherein each of the switchable waveplates is interposed between a pair of the one or more waveplate lenses.
16. The adaptive lens assembly of claim 15 , wherein the adaptive lens assembly comprises a plurality of the waveplate lenses and a plurality of the switchable waveplates, wherein the waveplate lenses and the switchable waveplate are alternatingly stacked.