Display-Integrated Eye Tracking to Mitigate HMD Occlusion
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Solution Overview
Problem
Current eye-tracking technologies in head-mounted displays (HMDs) are impaired by occlusion, which prevents accurate monitoring and tracking of a user's eyes.
Innovation Solution
Integrating eye-tracking components, such as light sensors and cameras, into the display assembly's conjugate optical plane, allowing for proper alignment and simultaneous illumination and sensing along the same optical path using a waveguide that carries both visible and invisible light for display and eye-tracking purposes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If eye-tracking components are placed separately from the display assembly, then the eye-tracking system can independently function, but occlusion occurs that prevents accurate monitoring of user's eyes
Solution Approach 1:
The patent merges the eye-tracking components with the display assembly by integrating sensors and light sources into the same optical structure. The display assembly's optical elements serve dual purposes: displaying visual content and enabling eye-tracking functionality. This integration eliminates occlusion issues because the eye-tracking components are positioned within the display's optical path rather than separately alongside it.
Solution Approach 2:
The display assembly is designed to perform multiple functions simultaneously: it displays visual content to the user while also serving as the platform for eye-tracking components. The optical elements of the display assembly are utilized for both illumination/display purposes and for sensing eye movements, making the system more efficient and eliminating the need for separate dedicated eye-tracking hardware that would cause occlusion.
2Reliability
If eye-tracking components are integrated into the display assembly, then occlusion is mitigated and accurate tracking is achieved, but the device complexity increases
Solution Approach 1:
The patent combines eye-tracking components with display assembly components into a unified structure. Rather than adding separate independent systems, the integration leverages existing display optical elements (lenses, light guides, displays) to also serve eye-tracking functions. This approach reduces the number of discrete components and simplifies the overall system architecture despite the advanced functionality achieved.
Solution Approach 2:
By designing the display assembly to perform dual functions (display and eye-tracking), the patent avoids the complexity of maintaining separate dedicated systems for each function. The shared optical path and components reduce the total component count and simplify system integration, as the same physical structures serve multiple purposes rather than requiring parallel independent systems.
3Device complexity
If the same optical path is used for both display and eye-tracking, then component integration is simplified, but light interference may occur between the two functions
Solution Approach 1:
The patent applies different optical properties to different regions or wavelengths within the same optical path. The display typically uses visible light wavelengths while eye-tracking sensors may use infrared or other non-visible wavelengths. By assigning different local optical characteristics (wavelengths, polarization states) to different functions within the shared optical path, the system enables both functions to operate simultaneously without significant interference.
Solution Approach 2:
The system utilizes changes in optical parameters (such as wavelength, intensity, or temporal modulation) to distinguish between display light and eye-tracking illumination. The display emits visible light at certain intensities and wavelengths, while eye-tracking light sources operate at different wavelengths or are modulated at specific frequencies. These parameter differences allow the shared optical path to carry multiple functions without cross-interference, as each function's light can be selectively detected or filtered.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Mitigates occlusion issues by ensuring both display pixels and eye-tracking sensors can view relevant eye features, enabling accurate gaze tracking and real-time adjustment of display parameters based on eye attributes.
Implementation Method 1
using a waveguide that carries both visible and invisible light for display and eye-tracking purposes
Implementation Method 2
one or more lights that shine onto the viewer's eyes and one or more optical sensors (e.g., cameras) that observe how the one or more lights are reflected by the viewer's eyes
Data Source
AI summary
An eyewear device comprising (1) a display assembly configured to generate graphical imagery for viewing by a user, (2) an eye-tracking device at least partially integrated into the display assembly, and (3) circuitry communicatively coupled to the eye-tracking device and configured to track an eye of the user based at least in part on light detected by the eye-tracking device. Various other apparatuses, systems, and methods are also disclosed.