AR Glasses Waveguide Coupling for Eye Tracking
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Solution Overview
Problem
Current augmented reality display devices with eye tracking functionality are complex in structure and require improvement in imaging quality.
Innovation Solution
A display device incorporating an optical waveguide with a coupling-in device and at least one coupling-out device, along with a first projector for visible light and a second projector for eye tracking illumination, which share a waveguide coupling system for coupling-in, coupling-out, and light splitting, and utilize a feedback tracking device to adjust the projected light according to the eye's gaze direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional eye tracking system is added to the display device, then eye tracking functionality is achieved, but the structure becomes complex
Solution Approach 1:
The patent combines the eye tracking illumination function and the AR display function into a single optical waveguide system. The coupling-in device and coupling-out device serve both the visible light for AR display and the infrared light for eye tracking, eliminating the need for separate illumination paths and reducing overall system complexity.
Solution Approach 2:
The optical waveguide substrate is designed to handle multiple wavelengths simultaneously - visible light for AR content display and infrared light for eye tracking illumination. The coupling devices are configured to work with both wavelength ranges, making the system multi-functional rather than requiring separate dedicated systems for each function.
2Reliability
If separate illumination systems are used for visible light and eye tracking, then each function can be optimized independently, but the device complexity and cost increase
Solution Approach 1:
The patent implements a universal optical coupling system where the same coupling-in device and coupling-out device handle both visible light from the first projector and infrared light from the second projector. This multi-functional design allows both functions to share the same optical path infrastructure, reducing component count while maintaining optimized performance for each wavelength through proper grating design.
Solution Approach 2:
The coupling devices use wavelength-dependent diffraction grating parameters to differentiate between visible and infrared light paths. By adjusting the grating period and orientation, the system can selectively couple different wavelengths into and out of the waveguide, enabling multi-functionality without requiring physically separate illumination systems.
3Reliability
If multiple projectors are used for visible light and eye tracking illumination, then each projector can be optimized for its specific wavelength, but the device complexity increases
Solution Approach 1:
The patent employs two projectors (first projector for visible light, second projector for infrared light) that feed into a shared optical waveguide system. While multiple light sources are used for wavelength-specific optimization, the coupling-in and coupling-out devices serve both projectors, creating a unified optical path that reduces overall system complexity compared to having completely separate illumination and display paths.
Solution Approach 2:
The system segments the light sources by wavelength function - visible light projector for AR content and infrared projector for eye tracking - while integrating them through a common waveguide platform. This segmentation allows independent optimization of each light source for its specific application while sharing the complex optical coupling infrastructure.
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 achieves a simplified structure, low cost, and improved eyeball imaging quality while providing an effective augmented reality display with eye tracking functionality.
Implementation Method 1
the coupling-in device is used for coupling the first light and the second light into the waveguide substrate
Implementation Method 2
the coupling-out device is used for coupling the first light and the second light at least partially out of the waveguide substrate to a human eye
Implementation Method 3
The coupling-out device propagates and expands the light carrying the image information
Data Source
AI summary
The present application provides a display device and glasses. The display device includes an optical waveguide, a first and second projectors, at least one optical sensing assembly, and a feedback tracking device. The first and second projectors respectively project a first light with a wavelength of visible light wavelength and a second light with a wavelength of second wavelength to a coupling-in device. The optical sensing assembly is arranged corresponding to a coupling-out device, and includes at least one imaging device. The feedback tracking device is electrically connected to the first projector and the light sensing assembly. The optical sensing assembly is used for receiving the second light reflected by human eye. The feedback tracking device adjusts the first projector according to the second light received by the optical sensing assembly such that the first light coupled out of the coupling-out device follows a line of sight of human eye.