Projection HMD Eye-Tracking Optical Path Sharing
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Solution Overview
Problem
Head-mounted display technologies face limitations in compactness, optical distortion, and user performance due to the lack of effective eye movement tracking capabilities, which are crucial for enhanced visualization accuracy and user interaction in applications like virtual reality and augmented reality.
Innovation Solution
A projection-based head-mounted display system with integrated eye-tracking capabilities, utilizing multiple infrared light sources and a camera to capture bright and dark pupil images, sharing the optical path between the display and eye-tracker for a compact, lightweight, and easy-to-use design, and optimizing the optical configuration for both display and tracking paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If eyepiece optics are used in head-mounted display, then the system provides see-through capability and optical augmentation, but the system lacks compactness and introduces large distortion for wide field of view
Solution Approach 1:
The patent merges the head-mounted display optics with eye-tracking optics by sharing common components including the lens, beam splitter, and retroreflective material. This integration allows the system to achieve both see-through capability and eye tracking functionality while reducing overall optical distortion through unified optical design.
Solution Approach 2:
The optical system is designed to serve multiple functions simultaneously: displaying virtual images, tracking eye movements, and providing see-through capability. The same lens and retroreflective material are used for both display and eye tracking, eliminating the need for separate optical paths and reducing distortion.
2Device complexity
If projection optics are used instead of eyepiece optics, then compactness and reduced optical distortion are achieved, but eye movement tracking capability is lost
Solution Approach 1:
The patent combines projection optics with eye-tracking capabilities by integrating a camera and infrared light sources into the existing projection display system. The same retroreflective material and optical path are utilized for both display and eye tracking, achieving compactness while adding versatility.
Solution Approach 2:
The projection optical system is extended to perform multiple functions: displaying virtual reality content and simultaneously tracking eye movements through infrared illumination and camera capture. This multi-functional design maintains compactness while enabling eye tracking.
3Reliability
If separate optical paths are used for display and eye tracking, then each function can be optimized independently, but system weight and complexity increase
Solution Approach 1:
The patent merges the optical paths for display and eye tracking by sharing common components such as the lens, beam splitter, and retroreflective material. This integration reduces system weight and complexity while maintaining the ability to optimize both functions through software-based eye tracking processing.
Solution Approach 2:
Instead of using separate optical paths, the system uses a single optical path where eye tracking is achieved by capturing reflected infrared light through the same optical components used for display. The camera captures eye reflections while the display projects virtual images through the same optical pathway.
4Measurement precision
If multiple infrared light sources are used for eye tracking, then accurate pupil imaging is achieved, but energy consumption increases
Solution Approach 1:
The patent uses multiple infrared light sources that can be activated periodically or selectively based on tracking requirements. The system activates infrared illumination only when eye tracking is needed, rather than continuously, reducing overall energy consumption while maintaining accurate pupil imaging during active tracking.
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 system achieves robust, accurate, and comfortable eye-tracking, reducing optical distortion and enhancing user performance by integrating eye-tracking into the head-mounted display, allowing for improved visualization and interaction without obstructing the user's view.
Implementation Method 1
multiple light sources for providing an infrared light to illuminate an eye of a user
Implementation Method 2
a camera for recording the eye, an optics for providing an optical path for a head-mounted display path and an eye-tracker path
Implementation Method 3
a first and a second optical device for imaging the eye to the camera positioned to reflect the infrared light and transmit a visible light
Implementation Method 4
The first and second optical device is selected from the group of a hot mirror and a beam-splitting cube
Data Source
AI summary
Methods, systems, apparatus and devices for the lens design of an HMPD with eye-tracking capabilities. The integration uses a low-level optical configuration in order to achieve a compact, comfortable, easy-to-use system. The optical system is further designed and optimized for sharing of the optical path between the HMD and the Eye-Tracker with minimal performance loss for both tasks.