Patent attributes
A head-mounted computing device having a convertible waveguide optical engine assembly is disclosed. The waveguide in accordance with aspects herein can be utilized in its transparent configuration, or may be provided with means for blocking light from passing through it either by using mechanical means, or by using different types of treatments that can switch the waveguide between opaque an transparent states based on an external stimulus, such as, for example, electricity, temperature, light, and the like. Further, the waveguide optical engine assembly comprises a compact footprint, which is advantageous for head-mounted computing devices. In addition to the compact footprint of the waveguide optical assembly, the configuration of the waveguide optical assembly, as disclosed, allows for maximization of advantages provided by the waveguide as related to eye box and eye relief.