Eye Tracking Using Beam Splitter and Single Pixel Detector
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Solution Overview
Problem
Existing eye tracking technologies in Head Mounted Displays (HMDs) require additional hardware like cameras, increasing space and cost, and are not efficient in determining eye movement and gaze direction.
Innovation Solution
The use of a single pixel detector and beam splitter in conjunction with a micro-display to project patterns onto the retina, allowing for the detection of reflected images and determination of eye movement and gaze direction without a camera, utilizing compressive sensing and Digital Micromirror Device technology for efficient image reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a camera is used for eye tracking in HMDs, then eye movement and gaze direction can be detected, but the device size, cost, and complexity increase
Solution Approach 1:
The patent extracts the eye tracking function from the traditional camera-based system and implements it using the existing display hardware. The display device itself is used to project patterns onto the retina, and the same display hardware detects the reflected light, eliminating the need for separate camera components while maintaining eye tracking functionality.
Solution Approach 2:
The display device performs multiple functions: it displays visual content to the user and simultaneously serves as the illumination source for eye tracking by projecting patterns onto the retina. The same display hardware also acts as the detector by capturing reflected light from the eye, making the system multi-functional and eliminating dedicated eye tracking hardware.
2Adaptability or versatility
If additional hardware is added for eye tracking, then eye movement detection capability is improved, but the space and cost of the HMD increase
Solution Approach 1:
The display device performs multiple functions: it displays visual content to the user and simultaneously serves as the illumination source for eye tracking by projecting patterns onto the retina. The same display hardware also acts as the detector by capturing reflected light from the eye, making the system multi-functional and eliminating dedicated eye tracking hardware.
Solution Approach 2:
The display system serves itself by using its own hardware components for both illumination and detection in the eye tracking process. The display projects patterns and simultaneously detects the reflected light from the eye, making the system self-sufficient and eliminating the need for external or additional dedicated components.
3Measurement precision
If patterns are projected continuously for eye tracking, then measurement accuracy is improved, but display luminosity and visibility are reduced
Solution Approach 1:
Instead of continuous pattern projection, the system uses periodic or intermittent projection of patterns at specific time intervals. This allows the display to maintain high luminosity during normal content display while periodically projecting patterns for eye tracking, thus achieving both accurate gaze detection and maintaining display visibility.
Solution Approach 2:
The system uses minimal pattern projection - only at isolated instances during content display - rather than continuous projection. This partial action approach provides sufficient data for accurate gaze detection while minimizing the impact on display luminosity and overall visibility for the user.
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 accurate and efficient eye tracking with minimal additional hardware, allowing for fast and precise determination of gaze direction, suitable for Virtual Reality and Augmented Reality applications, while maintaining display luminosity and visibility.
Implementation Method 1
a beam splitter, where the beam splitter is located relative to the display and the single pixel detector to allow a projected image from the display to pass through the beam splitter and direct a reflected image from an eye to the single pixel detector
Data Source
AI summary
An apparatus including a display; a single pixel detector; and a beam splitter. The beam splitter is located relative to the display and the single pixel detector to allow a projected image from the display to pass through the beam splitter and direct a reflected image from an eye to the single pixel detector, where the reflected image is based at least partially upon the projected image.