Scanning Display With Eye-Tracking Using MEMS Mirror
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Solution Overview
Problem
Existing eye-tracking systems in VR, AR, and MR devices require significant electrical power and processing resources for illumination and image analysis, leading to slower tracking speeds and increased power consumption.
Innovation Solution
A near-eye system that integrates a scanning display and eye-tracking system using a micro-electro-mechanical systems (MEMS) mirror to scan image and infrared light to an eyebox region, allowing for simultaneous virtual image presentation and eye-tracking, with a sensor generating tracking signals from returning infrared light, thereby simplifying calibration and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate illumination sources and camera-based detection systems are used for eye-tracking, then eye-tracking functionality is achieved, but power consumption and processing resources increase significantly
Solution Approach 1:
The patent combines the display illumination path and eye-tracking detection path into a single integrated optical system. The same illumination source serves dual purposes: presenting visual content to the user and providing illumination for eye-tracking detection. This merging eliminates the need for separate illumination sources and reduces processing overhead by using the existing display infrastructure for eye-tracking functions.
Solution Approach 2:
The illumination system is designed to perform multiple functions simultaneously. The light source used for displaying visual content also serves as the illumination source for eye-tracking. The detection system processes both display-related optical signals and eye-tracking signals through the same optical path, making the system universal and reducing overall component count and power consumption.
2Loss of information
If camera-based image analysis is used for eye-tracking, then gaze information is obtained, but processing resources and tracking speed are reduced
Solution Approach 1:
The patent replaces complex camera-based image processing with a simpler photodetector-based optical detection system. Instead of capturing and analyzing full images requiring significant computational resources, the system uses photodetectors to directly measure optical properties of reflected light from the eye. This substitution of detection methodology dramatically reduces processing requirements while maintaining tracking accuracy and increasing speed.
Solution Approach 2:
The system uses the existing display illumination infrastructure to create an optical copy of the illumination path for eye-tracking purposes. Rather than building a separate physical illumination system, the patent leverages the display's light sources and optical paths, creating an efficient optical copy that serves dual functions without requiring additional hardware or processing resources.
3Adaptability or versatility
If multiple separate systems are integrated into head-mounted displays, then functionality is enhanced, but weight and dimensions increase
Solution Approach 1:
The patent merges the display system and eye-tracking system into a single integrated optical architecture. The illumination sources, optical paths, and detection mechanisms are combined rather than implemented as separate subsystems. This integration shares common components such as light sources, waveguides, and optical elements, thereby reducing the total weight and volume while maintaining both display and eye-tracking functionalities.
Solution Approach 2:
The optical system is designed with multi-functionality, where the same hardware components serve multiple purposes. The illumination sources provide both display illumination and eye-tracking illumination. The detection system processes both display performance data and eye-tracking data. This universal design reduces the number of separate components needed, thereby reducing overall device weight and dimensions while enhancing functionality.
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 decreases power consumption, reduces the weight and dimensions of head-mounted displays, and enhances processing efficiency by utilizing the same scanner for both display and eye-tracking functions.
Implementation Method 1
A scanner such as a micro-electro-mechanical systems (MEMS) mirror may scan image light and infrared light
Implementation Method 2
a sensor (e.g. a photodiode) is included to generate a tracking signal in response to returning infrared light
Data Source
AI summary
Image light is generated with a display light source. The image light is visible. An infrared light source emits infrared light. A scan directs the image light and the infrared light to an input coupler of a display waveguide and the display waveguide presents the image light to an eyebox region as a virtual image.