Head-Mounted Display Systems With Alignment Monitoring

A head-mounted device, comprising:

• a head-mounted support structure with first and second opposing sides, wherein the second side is interposed between an eye box and the first side;
• a display coupled to the head-mounted support structure and configured to provide an image;
• an optical combiner with an output coupler configured to direct the image towards the eye box;
• a light-emitting device configured to emit light towards the optical combiner;
• and
• a sensor configured to gather gaze tracking information from the eye box, wherein the output coupler is configured to redirect the light from the light-emitting device toward the sensor and the optical combiner is interposed between the sensor and the first side of the head-mounted support structure.

A head-mounted device, comprising:

• a head-mounted support structure;
• a display configured to provide an image;
• a waveguide configured to direct the image from the display towards an eye box;
• a light source configured to emit first light that reflects from the head-mounted support structure and second light that illuminates the eye box;
• and
• a sensor configured to gather gaze tracking information from the eye box based at least partly on the second light that illuminates the eye box, wherein the sensor is configured to measure a misalignment of the image relative to the eye box by detecting the reflected light.