In late August, the U.S. Patent and Trademark Office officially published a patent application from Google that relates to how to make future smartglasses less bulky than those on the market today.

 

Google's patent notes that near-eye display devices such as eyewear display devices have multiple practical and leisure applications, but the development and adoption of wearable electronic display devices have been limited by the optics, aesthetics, manufacturing process, thickness, field of view, and prescription lens limitations of the optical systems used to implement existing display devices. For example, many conventional examples of eyewear display devices implement planar/flat waveguides in an attempt to achieve the maximum optical performance of the waveguide.

However, embedding a planar waveguide into a curved lens typically results in a lens configuration that is very bulky and unnatural looking on a user's face when compared to the sleeker and more streamlined look of typical curved eyeglass and sunglass lenses. As such, curved waveguide architectures have been developed to, among other things, overcome the constraints placed on lens and frame design for eyewear display devices by planar waveguides. Curved waveguides conform better to the curvature of a lens when compared to planar waveguides and allow for thinner lenses to be implemented within an eyewear display device.

However, the nonparallel or non-flat surfaces of a curved waveguide tend to propagate light at different angles, thereby reducing the optical performance of the waveguide. For example, the display information represented by the light can be deformed, and artifacts, such as ghosting, can be introduced into the displayed images.

Accordingly, described in Google patent are example waveguide configurations/ architectures that overcome the light deformation and artifact issues experienced by conventional curved waveguides. As described in greater detail below, a waveguide is embedded within a curved lens, such as an ophthalmic lens, of an eyewear display device or other near-eye display device.

The waveguide includes an input coupler, an exit pupil expander, and an output coupler. In a first configuration, the waveguide comprises a plurality of planar/flat piecewise sections.

Google's patent FIG. 1 below shows an example display system with a waveguide having a plurality of sections and incouplers; FIG. 2 is a diagram illustrating a cross-section view of an example implementation of the waveguide of FIG. 1.

Google's patent 11 above shows an examples of how images sources and/or incouplers are distributed relative to a lens.

For full details, review Google's patent application WO2024178217 that was published on August 29, 2024.