Color-corrected curved optical see-through thin lightguide with doublet and polarization grating

A method comprising:

• mounting a display to a head mountable frame, wherein the display emits light based on an electronic input signal;
• mounting a lightguide to the head mountable frame, wherein the lightguide is positioned to receive light from the display, wherein the lightguide includes:
• a first surface at an eye-side of the head mountable frame,
• a second surface at a world-side of the head mountable frame, wherein the second surface is positioned to reflect the emitted display light through the first surface to a first user eye, and wherein the light from the display is reflected by total internal reflection (TIR) within the lightguide,
• a first material having a first Abbe number, and
• a second material having a second Abbe number different from the first Abbe number;
• and
• mounting a polarization grating between the display and the lightguide;
• wherein the lightguide is configured to introduce a first chromatic aberration in the emitted light from the display incident on the lightguide;
• and
• wherein the polarization grating is configured to introduce a second chromatic aberration in the emitted light from the display, the second chromatic aberration providing at least partial color correction for the first chromatic aberration.

An apparatus comprising:

• a display coupled to a head-wearable frame;
• and
• a lightguide coupled to the head-wearable frame, wherein the lightguide is configured to direct light from the display toward an eye-direction, the lightguide including:
• a transparent first surface on an eye-side of the lightguide,
• a transparent second surface on a world-side of the lightguide,
• a first material having a first Abbe number,
• a second material having a second Abbe number different from the first Abbe number, and
• a transparent curved surface as a combiner surface configured to reflect the light from the display to a user eye and combine the display light with ambient light entering from a world-side through the transparent second surface of the lightguide;
• and
• a polarization grating disposed between the display and the lightguide.