Waveguide display with total internal reflection band between color channels

An electronic device comprising:

• a waveguide having a first substrate, a second substrate, a grating medium interposed between the first substrate and the second substrate, and a third substrate layered between the grating medium and the first substrate, the waveguide being configured to propagate light via total internal reflection (TIR);
• volume holograms in the grating medium and configured to couple the light out of the waveguide;
• and
• a surface relief grating (SRG) in the third substrate, wherein
• the SRG is configured to receive the light from within the first substrate,
• the SRG is configured to diffract the light towards the volume holograms,
• the light has a first color channel,
• the light has a second color channel different from the first color channel,
• the SRG is configured to diffract the first color channel of the light onto a first side of a TIR transition angle of the first substrate, and
• the SRG is configured to diffract the second color of the light onto a second side of the TIR transition angle of the first substrate.

An electronic device comprising:

• a first substrate;
• a second substrate;
• a grating medium interposed between the first substrate and the second substrate, wherein the first substrate is configured to propagate at least a first color channel and a second color channel of light via total internal reflection (TIR);
• a third substrate layered between the first substrate and the grating medium;
• and
• a surface relief grating (SRG) in the third substrate, wherein the SRG is configured to
• diffract the first color channel of the light from a first k-space region onto a second k-space region, and
• diffract the second color channel of the light from the first k-space region onto a third k-space region, the first substrate having a TIR transition angle between the second k-space region and the third k-space region.