Lens assembly including a volume Bragg grating and display device including the same

A display device comprising:

• a display configured to output image light and to transmit ambient light;
• and
• an optical assembly comprising:
• a reflector;
• and
• a volume Bragg grating positioned for (i) transmitting light having a first polarization and incident upon the volume Bragg grating at an incident angle that is within a first angular range, (ii) reflecting light having the first polarization and incident upon the volume Bragg grating at an incident angle that is within a second angular range distinct from the first angular range, and (iii) transmitting light having a second polarization that is different from the first polarization, wherein the optical assembly is configured to:
• receive the image light, having the first polarization, and transmit the image light so that the image light is reflected at the reflector and at the volume Bragg grating before the image light is output from the optical assembly;
• and
• receive the ambient light, having the second polarization, and output the ambient light from the optical assembly without undergoing reflection at either the reflector or the volume Bragg grating.

A method of transmitting light through an optical assembly, the method comprising:

• transmitting image light, including:
• receiving the image light at an optical assembly including a reflector and a volume Bragg grating, wherein the volume Bragg grating is positioned for (i) transmitting light having a first polarization and incident upon the volume Bragg grating at an incident angle that is within a first angular range, (ii) reflecting light having the first polarization and incident upon the volume Bragg grating at an incident angle that is within a second angular range distinct from the first angular range, and (iii) transmitting light having a second polarization that is different from the first polarization;
• and
• outputting the image light from the optical assembly at a first optical power via a first optical path that includes reflection at the reflector and at the volume Bragg grating;
• and
• transmitting ambient light in a second optical path that is different from the first optical path, the transmitting including:
• receiving the ambient light at the optical assembly;
• and
• outputting the ambient light from the optical assembly at a second optical power via an optical path that does not include reflection at either the reflector or the volume Bragg grating, the second optical power being less than the first optical power.