Waveguide Display Gratings for Integrated Gaze Tracking
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Solution Overview
Problem
Designing electronic devices such as virtual and augmented reality headsets with displays that are aesthetically pleasing, compact, and efficient in power consumption while maintaining desired optical performance is challenging.
Innovation Solution
Incorporating a display module with a waveguide that uses surface relief gratings for image light coupling and infrared light coupling, along with a cross-coupler for image light redirection and infrared light tracking, to create a head-mounted device with gaze tracking capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If traditional display components are used in virtual and augmented reality headsets, then the displays can present images to users, but the components become unsightly and bulky
Solution Approach 1:
The patent combines the display function and gaze tracking function into a single integrated optical system. The waveguide serves dual purposes: displaying virtual images and tracking user gaze through infrared light coupling. This merging eliminates the need for separate bulky display components and gaze tracking components, directly resolving the contradiction between compact shape and structural complexity.
Solution Approach 2:
The surface relief grating structure performs multiple functions simultaneously: it couples visible light into and out of the waveguide for display, and couples infrared light for gaze tracking. This multi-functionality allows a single component to replace what would traditionally require multiple separate components, reducing overall device size and complexity while maintaining both display and tracking capabilities.
2Adaptability or versatility
If multiple separate components are used for display and gaze tracking, then each component can perform its specific function, but the overall device becomes bulky and power-consuming
Solution Approach 1:
The patent merges the display optical path and gaze tracking optical path into a single waveguide system. By using the same waveguide structure for both visible light display and infrared light tracking, the system eliminates redundant components and reduces overall power consumption while maintaining full functionality for both display and gaze tracking operations.
Solution Approach 2:
The waveguide and surface relief gratings serve universal purposes by handling both display and gaze tracking functions. This multi-functionality reduces the total number of active components, thereby reducing cumulative power consumption while preserving adaptability for both virtual image display and user gaze tracking.
3Device complexity
If a single surface relief grating is used for both visible and infrared light coupling, then device complexity is reduced, but optical performance must be optimized for multiple wavelengths
Solution Approach 1:
The patent applies local quality by designing the surface relief grating with different local properties: one set of gratings optimized for visible light coupling and another set optimized for infrared light coupling. This allows each region of the grating structure to be precisely tuned for its specific wavelength, maintaining high optical performance while using a unified physical structure that reduces overall device complexity.
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
The solution provides a compact and efficient display system that allows seamless viewing of both virtual and real-world content while effectively tracking user gaze, enhancing user experience and reducing power consumption.
Implementation Method 1
a surface relief grating on the waveguide, the surface relief grating is configured to diffract the infrared light
Implementation Method 2
a waveguide configured to direct image light
Data Source
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AI summary
A display may include a waveguide. An input coupler may couple image light into the waveguide and an output coupler may couple the image light out of the waveguide. A surface relief grating on the waveguide may couple infrared light into the waveguide and may couple the infrared light out of the waveguide. The surface relief grating may additionally or alternatively couple reflected infrared light into the waveguide and out of the waveguide and towards an infrared sensor. The surface relief grating may also form a cross-coupler for the image light. The infrared sensor may gather infrared sensor data based on the reflected infrared light. Control circuitry may perform gaze tracking operations based on the infrared sensor data. The input and output couplers may also be formed from surface relief gratings or may include other optical components.