Optical systems with multi-layer holographic combiners

A method of operating an electronic device comprising:

• with a projector in a first portion of a housing for the electronic device, generating light;
• with a first diffractive grating in a second portion of the housing, diffracting a first portion of the light to an eye box;
• with a second diffractive grating in the second portion of the housing, diffracting a second portion of the light to an optical sensor;
• with the optical sensor, generating sensor data based on the second portion of the light;
• and
• with the projector, adjusting the light based on a misalignment between the projector and the first and second diffractive gratings as identified by the sensor data.

An electronic device comprising:

• a light source configured to generate light containing images;
• an optical sensor;
• and
• an optical combiner configured to transmit world light to an eye box, wherein
• the optical combiner comprises diffractive gratings configured to diffract a first portion of the light to the eye box and to diffract a second portion of the light to the optical sensor,
• the optical sensor is configured to generate sensor data based on the second portion of the light, and
• the light source is configured to adjust the images in the light based on a misalignment between the light source and the optical combiner as identified by the sensor data.