Switchable Gratings for Compact Near-Eye Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing near-eye displays face challenges in integrating eye tracking optics efficiently due to the need for multiple illuminating light sources, which increase cost, complexity, and energy consumption, while also requiring compact and comfortable designs.
Innovation Solution
Implementing switchable gratings in the optical path of near-eye displays to redirect illuminating light to the eyebox, allowing for time-division multiplexing between image displaying and eye tracking modes, reducing the number of light sources and optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple illuminating light sources are used for eye tracking, then eye tracking accuracy is improved, but device complexity and energy consumption increase
Solution Approach 1:
The display grating is designed to perform dual functions: serving as the display output grating during image display mode and as the eye tracking grating during eye tracking mode. This eliminates the need for separate gratings for display and eye tracking, reducing the number of optical components while maintaining eye tracking accuracy through the single multifunctional grating structure
Solution Approach 2:
The patent combines the display grating and eye tracking grating into a single integrated grating structure. By merging these two previously separate components into one, the system reduces component count and complexity while achieving both display and eye tracking functions through the same optical element
2Measurement precision
If multiple illuminating light sources are used for eye tracking, then eye tracking accuracy is improved, but energy consumption increases
Solution Approach 1:
The system employs time-division multiplexing where the single grating alternates between display mode and eye tracking mode at different time intervals. During eye tracking mode, the grating redirects illuminating light to the eyebox for tracking; during display mode, it performs its display function. This periodic switching allows accurate eye tracking using a single grating and light source, significantly reducing energy consumption compared to continuous operation of multiple light sources
Solution Approach 2:
The grating's optical function is dynamically switched between display and eye tracking modes through time-division multiplexing control. This dynamic reconfiguration allows the same optical component to serve different purposes at different times, optimizing energy usage by activating eye tracking illumination only when needed rather than continuously
3Weight of moving object
If compact configuration is implemented, then device weight is reduced, but optical throughput may be compromised
Solution Approach 1:
The single grating performs both display and eye tracking functions, eliminating the need for separate gratings and reducing the overall number of optical components. This consolidation achieves compact configuration and reduced device weight while maintaining optical throughput efficiency by using one optimized grating structure for both functions rather than multiple separate components
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
This approach enables a compact and efficient near-eye display configuration by minimizing the number of light sources, lowering costs and energy consumption, and improving optical throughput while maintaining accurate eye tracking.
Implementation Method 1
a switchable grating structure optically coupled to the light source for receiving and redirecting the illuminating light to a location of the eye at an eyebox
Data Source
AI summary
A switchable grating may be used to redirect illuminating light for illuminating a user's eye in an eye tracking system, to facilitate the determination of eye position and/or orientation. The eye tracking system may be used in a near-eye display. An eye tracking camera obtains an eye image, and a controller performs an initial determination of the eye position. The controller may switch the switchable grating to direct the illuminating light beam onto the eye, for a better position and/or eye orientation determination.