Waveguide based imaging system for object tracking and waveguide based display system for reducing world side ghost
A system is provided. The system includes a light source configured to emit a infrared (“IR”) light for illuminating an object. The system also includes a waveguide imaging assembly including a waveguide, an in-coupling element disposed at a first portion of the waveguide, an out-coupling element disposed at a second portion of the waveguide, and an optical sensor disposed facing the out-coupling element. The in-coupling element is configured to couple the IR light reflected by the object into the waveguide, the waveguide is configured to guide the IR light to propagate toward the out-coupling element through total internal reflection, and the out-coupling element is configured to couple the IR light out of the waveguide toward the optical sensor. The optical sensor is configured to generate a tracking signal of the object based on the IR light output from the waveguide.
1 . A system, comprising:
a light source configured to emit an infrared (“IR”) light for illuminating an object; and
a waveguide imaging assembly including a waveguide comprising:
a first in-coupling element disposed at a first portion of the waveguide,
a first out-coupling element disposed at a second portion of the waveguide,
a second in-coupling element disposed at the second portion of the waveguide,
a second out-coupling element disposed at the first portion of the waveguide, and
an optical sensor disposed facing the first out-coupling element,
wherein:
the first in-coupling element is configured to couple the IR light reflected by the object into the waveguide, the waveguide is configured to guide the IR light to propagate toward the first out-coupling element through total internal reflection, and the first out-coupling element is configured to couple the IR light out of the waveguide toward the optical sensor,
the second in-coupling element and the second out-coupling element are configured to deflect a visible light, and substantially transmit, with negligible deflection, the IR light, and
the optical sensor is configured to generate a tracking signal of the object based on the IR light output from the waveguide.
2 . The system of claim 1 , wherein the first in-coupling element and the first out-coupling element are configured to deflect the IR light, and substantially transmit, with negligible deflection, a visible light.
3 . The system of claim 1 , wherein
the waveguide is configured to guide the IR light to propagate toward the first out-coupling element along a width direction of the waveguide via total internal reflection, and
along the width direction of the waveguide, a width of the first in-coupling element is configured to be at a sub-millimeter level.
4 . The system of claim 3 , wherein the width of the first in-coupling element is configured to be 200-300 micrometers, 300-400 micrometers, 400-500 micrometers, or 500-600 micrometers.
5 . The system of claim 1 , wherein the optical sensor is disposed off-axis with respect to the object.
6 . The system of claim 1 , wherein at least one of the first in-coupling element or the first out-coupling element includes a diffraction grating.
7 . The system of claim 1 , wherein:
the second in-coupling element is configured to couple the visible light representing a virtual image into the waveguide as an in-coupled visible light that propagates inside the waveguide via total internal reflection, and
the second out-coupling element is configured to couple the in-coupled visible light out of the waveguide as one or more output visible lights toward an eye-box region of the system.
8 . The system of claim 1 , wherein along a width direction of the waveguide, a width of the first in-coupling element is smaller than a width of the second out-coupling element.
9 . The system of claim 1 , wherein the light source is a first light source, and the system further comprises:
a second light source disposed facing the second portion of the waveguide, and configured to output the visible light toward the second in-coupling element.
10 . The system of claim 1 , wherein the optical sensor and the object are disposed at the same side of the waveguide, or at different sides of the waveguide.
11 . A system, comprising:
a light source configured to emit an infrared (“IR”) light for illuminating an object; and
a waveguide imaging assembly comprising:
a first waveguide comprising a first in-coupling element disposed at a first portion of the first waveguide and a first out-coupling element disposed at a second portion of the first waveguide,
a second waveguide stacked with the first waveguide, the second waveguide comprising a second out-coupling element disposed at a first portion of the second waveguide, and a second in-coupling element disposed at a second portion of the second waveguide, and
an optical sensor disposed facing the first out-coupling element,
wherein:
the first in-coupling element is configured to couple the IR light reflected by the object into the first waveguide, the first waveguide is configured to guide the IR light to propagate toward the first out-coupling element through total internal reflection, and the first out-coupling element is configured to couple the IR light out of the first waveguide toward the optical sensor,
the second in-coupling element and the second out-coupling element are configured to deflect a visible light, and substantially transmit, with negligible deflection, the IR light, and
the optical sensor is configured to generate a tracking signal of the object based on the IR light output from the first waveguide.
12 . The system of claim 11 , wherein:
the second in-coupling element is configured to couple the visible light representing a virtual image into the second waveguide as an in-coupled visible light that propagates inside the second waveguide via total internal reflection, and
the second out-coupling element is configured to couple the in-coupled visible light out of the second waveguide as one or more output visible lights toward an eye-box region of the system.
13 . The system of claim 11 , wherein along a width direction of the second waveguide, a width of the first in-coupling element is smaller than a width of the second out-coupling element.
14 . The system of claim 11 , wherein the light source is a first light source, and the system further comprises:
a second light source disposed facing the second portion of the second waveguide, and configured to output the visible light toward the second in-coupling element.