Smart glasses have emerged as one of the most exciting new tech device categories. Meta has been making strides with its Ray-Ban Meta glasses and its AR glasses prototype, Project Orion. Meanwhile, Apple was recently granted a patent by the U.S. Patent Office, as highlighted in a report by Patently Apple, detailing innovations in its smart glasses project.
Apple’s new patent focuses on an advanced eye-tracking technique that strategically positions light sources on a transparent substrate, reducing the thickness of the frame around the lenses, as highlighted by the report.
As the report indicates, eye-tracking involves determining the location of light sources, such as infrared (IR) LEDs, micro-IR LEDs, or mini-IR LEDs. These light sources reflect off the user’s eye and are captured by an image sensor to assess eye characteristics like gaze direction, eye orientation, or iris identification.
Traditionally, in head-mounted systems, light sources are placed along the edges of the device, such as the frame of glasses. However, this setup often requires additional cameras to capture enough reflected light points (glints) for accurate eye-tracking, as the report notes. Apple’s approach addresses this limitation by positioning the light sources on a transparent substrate.
By embedding light sources on a transparent substrate, Apple’s design allows for greater flexibility in light source placement. This not only improves the accuracy of glint detection but also enhances the overall performance of the eye-tracking system.
Furthermore, Apple’s multi-stack architecture integrates the light sources into the middle layer of the stack, aligning them closer to the optical axis of the user’s eye. This configuration offers improved precision compared to rim-mounted light sources, as indicated by the report.
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(Photo credit: Apple)