Heat generated by the light engines of augmented reality (AR) smart glasses can degrade image quality by causing structural deformations, variations in optical path lengths, and inhomogeneity in the refractive index profile of the glasses or optical components therein. This disclosure describes techniques for passively cooling a display subassembly (DSA) unit of smart glasses by leveraging the relatively large surface area of a waveguide combiner to exchange heat with free space. Heat exchange can be accomplished by surface texturing of the waveguide combiner to improve cooling via convection and/or by surface coatings of the boundary of the waveguide combiner to enhance cooling via conduction. By reducing the temperature of the light engine, the techniques improve the optical performance of the DSA. By reducing the temperature gradient throughout the waveguide combiner, the techniques reduce or eliminate image artifacts arising from refractive-index inhomogeneities.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.