Holographically displaying three-dimensional objects
Methods, apparatus, devices, subsystems, and systems for holographically displaying three-dimensional objects are provided. In one aspect, an optical device includes: an optical guiding device configured to guide light to propagate along a first direction within the optical guiding device, the light including multiple colors of light; an in-coupling diffractive structure configured to diffract the light to propagate in the optical guiding device; and a plurality of out-coupling diffractive structures arranged downstream of the in-coupling diffractive structure along the first direction and configured to diffract at least part of the light out of the optical guiding device along a second direction different from the first direction. The optical device can be configured for at least one of: color crosstalk suppression among the multiple colors of light, display zero order light suppression, dispersion compensation, or ambient light blocking.
1. An optical device, comprising:
an optical guiding device configured to guide light to propagate along a first direction within the optical guiding device, the light comprising multiple colors of light;
an in-coupling diffractive structure configured to diffract the light to propagate in the optical guiding device; and
a plurality of out-coupling diffractive structures arranged downstream of the in-coupling diffractive structure along the first direction and configured to diffract at least part of the light out of the optical guiding device along a second direction different from the first direction,
wherein each of the plurality of out-coupling diffractive structure comprises:
multiple optically diffractive components respectively for the multiple colors of light; and
one or more color-selective polarizers configured to rotate a polarization state of one or more colors of the multiple colors of light such that each color of light is diffracted out by a corresponding optically diffractive component along the second direction.
2. The optical device of claim 1 , wherein the multiple optically diffractive components comprise:
a first optically diffractive component configured to: i) diffract a first color of light in a first polarization state incident at a first incident angle with a first diffraction efficiency at a first diffracted angle; and ii) diffract a second color of light in a second polarization state incident at a second incident angle with a diffraction efficiency that is substantially less than the first diffraction efficiency;
a color-selective polarizer configured to rotate a polarization state of the second color of light in the second polarization state incident on the color-selective polarizer from the second polarization state to the first polarization state; and
a second optically diffractive component configured to diffract the second color of light in the first polarization state incident at the second incident angle with a second diffraction efficiency at a second diffracted angle,
wherein the color-selective polarizer is between the first and second optically diffractive components, wherein the second optically diffractive component is configured to transmit the first color of light diffracted at the first diffracted angle, and the first color of light is different from the second color of light.
3. The optical device of claim 2 , wherein the second optically diffractive component is configured to diffract the first color of light in the second polarization state at the first incident angle with a diffraction efficiency substantially smaller than the second diffraction efficiency, and
wherein the first optically diffractive component, the color-selective polarizer, and the second optically diffractive component are sequentially stacked, such that the first color of light and the second color of light are incident on the first optically diffractive component before the first color of light and the second color of light are incident on the second optically diffractive component.
4. The optical device of claim 1 , wherein the diffracted light diffracted by the in-coupling diffractive structure propagates via total internal reflection in the optical guiding device along the first direction to be sequentially incident on each of the plurality of out-coupling diffractive structures along the first direction, and
wherein the plurality of out-coupling diffractive structures are configured to have gradually increased diffraction efficiencies for the light along the first direction, such that diffracted light diffracted by each of the plurality of out-coupling diffractive structures out of the optical guiding device has a same optical power.
5. The optical device of claim 4 , wherein the diffracted light diffracted by the in-coupling diffractive structure is incident on each of the plurality of out-coupling diffractive structures with a same incident angle, and
wherein each of the plurality of out-coupling diffractive structures is configured such that the diffracted light diffracted by each of the plurality of out-coupling diffractive structures has a same diffraction angle.
6. The optical device of claim 1 , wherein, for each color of the multiple colors of light:
the in-coupling diffractive structure comprises a corresponding first diffraction grating for light of the color;
each of the plurality of out-coupling diffractive structures comprises a corresponding second diffraction grating for the light of the color; and
the corresponding first diffraction grating and the corresponding second diffraction grating are configured to cause opposite dispersions having a same magnitude for the light of the color.
7. The optical device of claim 6 , wherein, for each color of the multiple colors of light, each of the corresponding first diffraction grating and the corresponding second diffraction grating is a reflection grating.
8. The optical device of claim 1 , further comprising an optically redirecting component, wherein:
each of the plurality of out-coupling diffractive structures is configured to diffract the light at an incident angle onto a display;
for the light that is incident on the display at the incident angle, the display diffracts the light; and
the optically redirecting component is configured to transmit a portion of the light diffracted by the display to provide a holographic scene and to redirect display zero order light away from the holographic scene in a three-dimensional (3D) space, the display zero order light comprising reflected light from the display.
9. The optical device of claim 8 , wherein the plurality of out-coupling diffractive structures are arranged on a first side of the optical guiding device facing to the display, and the optically redirecting component is arranged on a second side of the optical guiding device that is opposite to the first side.
10. The optical device of claim 8 , wherein the optical redirecting component comprises multiple redirecting holographic gratings for the display zero order light of the multiple colors of light, and wherein each redirecting holographic grating is configured to diffract display zero order light of a respective color of light of the multiple colors of light at a respective diffractive angle towards a respective direction in the 3D space.
11. The optical device of claim 1 , further comprising:
a linear polarizer configured to transmit light with a linear polarization state; and
an optical retarder configured to alter a polarization state of light passing through the optical retarder,
wherein the linear polarizer and the optical retarder are configured to cause ambient light coming from a first side of the linear polarizer to pass through the linear polarizer and the optical retarder to be incident on a display and deflected back from the display to pass through the optical retarder to be blocked from a second side of the linear polarizer by the linear polarizer, the second side of the linear polarizer being opposite to the first side of the linear polarizer, and
wherein the optical device, the linear polarizer, and the optical retarder are configured to cause the light to be incident on the display and deflected back from the display to transmit from the second side of the linear polarizer through the linear polarizer.
12. An optical device, comprising:
an optical guiding device configured to guide light to propagate along a first direction within the optical guiding device, the light comprising multiple colors of light;
an in-coupling diffractive structure configured to diffract the light to propagate in the optical guiding device; and
a plurality of out-coupling diffractive structures arranged downstream of the in-coupling diffractive structure along the first direction and configured to diffract at least part of the light out of the optical guiding device along a second direction different from the first direction,
wherein each of the plurality of out-coupling diffractive structures comprises:
multiple optically diffractive components respectively for the multiple colors of light; and
one or more reflective layers configured to totally reflect a single color of light and transmit one or more other colors of light such that each color of light is diffracted out by a corresponding optically diffractive component along the second direction.
13. The optical device of claim 12 , wherein each of the plurality of out-coupling diffractive structures comprises:
a first optically diffractive component comprising a first diffractive structure configured to diffract a first color of light having a first incident angle at a first diffracted angle;
a second optically diffractive component comprising a second diffractive structure configured to diffract a second color of light having a second incident angle at a second diffracted angle, the second incident angle being different from the first incident angle;
a first reflective layer configured to totally reflect the first color of light having the first incident angle and transmit the second color of light having the second incident angle; and
a second reflective layer configured to totally reflect the second color of light having the second incident angle and to transmit the first color of light diffracted at the first diffracted angle and the second color of light diffracted at the second diffracted angle,
wherein the first reflective layer is between the first and second diffractive structures, and the second diffractive structure is between the first and second reflective layers.
14. The optical device of claim 12 , wherein the diffracted light diffracted by the in-coupling diffractive structure propagates via total internal reflection in the optical guiding device along the first direction to be sequentially incident on each of the plurality of out-coupling diffractive structures along the first direction, and
wherein the plurality of out-coupling diffractive structures are configured to have gradually increased diffraction efficiencies for the light along the first direction, such that diffracted light diffracted by each of the plurality of out-coupling diffractive structures out of the optical guiding device has a same optical power.
15. The optical device of claim 12 , wherein, for each color of the multiple colors of light:
the in-coupling diffractive structure comprises a corresponding first diffraction grating for light of the color;
each of the plurality of out-coupling diffractive structures comprises a corresponding second diffraction grating for the light of the color; and
the corresponding first diffraction grating and the corresponding second diffraction grating are configured to cause opposite dispersions having a same magnitude for the light of the color.
16. The optical device of claim 12 , further comprising an optically redirecting component,
wherein each of the plurality of out-coupling diffractive structures is configured to diffract the light at an incident angle onto a display;
for the light that is incident on the display at the incident angle, the display diffracts the light; and
the optically redirecting component is configured to transmit a portion of the light diffracted by the display to provide a holographic scene and to redirect display zero order light away from the holographic scene in a three-dimensional (3D) space, the display zero order light comprising reflected light from the display.
17. The optical device of claim 16 , wherein the plurality of out-coupling diffractive structures are arranged on a first side of the optical guiding device facing to the display, and the optically redirecting component is arranged on a second side of the optical guiding device that is opposite to the first side.
18. The optical device of claim 12 , further comprising:
a linear polarizer configured to transmit light with a linear polarization state; and
an optical retarder configured to alter a polarization state of light passing through the optical retarder,
wherein the linear polarizer and the optical retarder are configured to cause ambient light coming from a first side of the linear polarizer to pass through the linear polarizer and the optical retarder to be incident on a display and deflected back from the display to pass through the optical retarder to be blocked from a second side of the linear polarizer by the linear polarizer, the second side of the linear polarizer being opposite to the first side of the linear polarizer, and
wherein the optical device, the linear polarizer, and the optical retarder are configured to cause the light to be incident on the display and deflected back from the display to transmit from the second side of the linear polarizer through the linear polarizer.
19. An optical device, comprising:
an optical guiding device configured to guide light to propagate along a first direction within the optical guiding device;
an in-coupling diffractive structure configured to diffract the light to propagate in the optical guiding device;
a plurality of out-coupling diffractive structures arranged downstream of the in-coupling diffractive structure along the first direction and configured to diffract at least part of the light out of the optical guiding device along a second direction different from the first direction at an incident angle onto a display so that the light is diffracted from the display; and
an optically redirecting component configured to transmit a portion of the light diffracted by the display to form a holographic scene and to redirect display zero order light away from the holographic scene in a three-dimensional (3D) space, the display zero order light comprising reflected light from the display.
20. The optical device of claim 19 , wherein the light comprising multiple colors of light, and each of the plurality of out-coupling diffractive structures comprises:
multiple optically diffractive components, each optically diffractive component configured to diffract a color of light of the multiple colors of light; and
one or more reflective layers configured to totally reflect a single color of light and to transmit one or more other colors of light such that each color of light is diffracted out by a corresponding optically diffractive component along the second direction.
21. The optical device of claim 19 , wherein the light comprising multiple colors of light, and each of the plurality of out-coupling diffractive structure comprises:
multiple optically diffractive components respectively for the multiple colors of light; and
one or more color-selective polarizers configured to rotate a polarization state of one or more colors of the multiple colors of light such that each color of light is diffracted out by a corresponding optically diffractive component along the second direction.
22. The optical device of claim 19 , wherein the diffracted light from the in-coupling diffractive structure propagates via total internal reflection in the optical guiding device along the first direction to be sequentially incident on each of the plurality of out-coupling diffractive structures along the first direction, and
wherein the plurality of out-coupling diffractive structures are configured to have gradually increased diffraction efficiencies for the light along the first direction, such that diffracted light by each of the plurality of out-coupling diffractive structures out of the optical guiding device has a same optical power.
23. The optical device of claim 19 , wherein the light comprising multiple colors of light,
for each color of the multiple colors of light,
the in-coupling diffractive structure comprises a corresponding first diffraction grating for light of the color,
each of the plurality of out-coupling diffractive structures comprises a corresponding second diffraction grating for the light of the color, and
wherein the corresponding first diffraction grating and the corresponding second diffraction grating are configured to cause opposite dispersions having a same magnitude for the light of the color.
24. The optical device of claim 19 , further comprising:
a linear polarizer configured to transmit light with a linear polarization state; and
an optical retarder configured to alter a polarization state of light passing through the optical retarder,
wherein the linear polarizer and the optical retarder are configured to cause ambient light coming from a first side of the linear polarizer to pass through the linear polarizer and the optical retarder to be incident on a display and deflected back from the display to pass through the optical retarder to be blocked from a second side of the linear polarizer by the linear polarizer, the second side of the linear polarizer being opposite to the first side of the linear polarizer, and
wherein the optical device, the linear polarizer, and the optical retarder are configured to cause the light to be incident on the display and deflected back from the display to transmit from the second side of the linear polarizer through the linear polarizer.