Image light guide with circular polarizer

An imaging apparatus for conveying a virtual image, comprising:

• an image light guide having first and second surfaces, an in-coupling diffractive optic arranged along one of the first and second surfaces, and an out-coupling diffractive optic arranged along one of the first and second surfaces;
• the in-coupling diffractive optic being arranged to diffract image-bearing light beams into the image light guide, wherein at least a portion of the image-bearing light beams propagate to the out-coupling diffractive optic by internal reflections from the first and second surfaces;
• the out-coupling diffractive optic being arranged to diffract the image-bearing light beams through the second surface of the image light guide toward an eyebox whereby a virtual image is viewable from within the eyebox;
• an at least partially transparent outer cover operable to protect at least part of the image light guide from environmental influences while supporting views of an environment through both the image light guide and the outer cover;
• and
• a circular polarizer arranged between the image light guide and the outer cover such that image-bearing light beams exiting through the first surface of the image light guide propagate through the circular polarizer to the outer cover and at least a portion of the image-bearing light beams exiting through the first surface are prevented from reentering the image light guide;
• wherein the circular polarizer is operable to circularly polarize at least a portion of image-bearing light beams transmitted through the first surface, and wherein the circularly polarized light is reflected from the outer cover as circularly polarized light of an opposite rotational orientation.

An imaging apparatus for conveying a virtual image, comprising:

• first and second optical subsystems;
• the first optical subsystem arranged to convey a first portion of image-bearing light to an eyebox, wherein a second portion of image-bearing light is emitted from the first optical subsystem as escaped light;
• the second optical subsystem comprising a partially reflective surface operable to reflect at least a portion of the second portion of image-bearing light back toward the first optical system as reflected light;
• and
• a circular polarizer arranged between the first and second optical subsystems to transmit a portion of the escaped light to the partially reflective surface and to prevent at least a portion of the reflected light from reentering the first optical subsystem,
• wherein the escaped light transmitted through the circular polarizer is circularly polarized in a first rotational orientation, and the reflected light is circularly polarized in a second rotational orientation opposite the first rotational orientation.

An imaging apparatus for conveying a virtual image, comprising:

• a waveguide having first and second surfaces;
• an in-coupling diffractive optic arranged along one of the first and second surfaces, wherein the in-coupling diffractive optic is operable to direct image-bearing light beams into the waveguide, wherein the waveguide is operable to propagate the image-bearing light beams along the waveguide by internal reflections from the first and second surfaces;
• an out-coupling diffractive optic arranged along one of the first and second surfaces of the waveguide, wherein the out-coupling diffractive optic is operable to direct at least a portion of the image-bearing light beams from the waveguide through the second surface toward an eyebox;
• an at least partially transparent outer cover located adjacent to the first surface;
• and
• a circular polarizer arranged between the waveguide and the outer cover, wherein the circular polarizer is operable to circularly polarize at least a portion of image-bearing light beams transmitted through the first surface and to prevent at least a portion of image-bearing light beams transmitted through the first surface from reentering the waveguide as a result of reflection from the outer cover,
• wherein the circular polarizer is arranged such that the at least a portion of image-bearing light beams transmitted through the first surface is circularly polarized light of a first rotational orientation, and wherein the circularly polarized light of a first rotational orientation is reflected from the outer cover as circularly polarized light of a second rotational orientation opposite the first rotational orientation.