VR Headset Eye Tracking for Interpupillary Distance Adjustment
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Solution Overview
Problem
Conventional head-mounted displays (HMDs) face challenges in accommodating variations in interpupillary distance and eye relief among users, leading to optical distortions due to suboptimal eye box placement.
Innovation Solution
A virtual reality system that determines interpupillary distance and eye relief using illumination sources and an image capture device, such as a camera, to accurately position lenses within the HMD, ensuring proper alignment and minimizing distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional HMDs are designed to accommodate a range of user anatomies, then the device can be used by more users, but ideal eye box placement is sacrificed for all users
Solution Approach 1:
The system performs preliminary measurement of the user's interpupillary distance and eye relief before the user begins using the HMD. The illumination sources and image capture device measure these anatomical parameters in advance, allowing the system to pre-adjust the optical configuration to match the specific user's anatomy, thereby achieving both broad adaptability and precise eye box placement.
Solution Approach 2:
The HMD incorporates adjustable optical elements that can dynamically change their position or configuration based on the measured user anatomy. The system adjusts the eye box placement in real-time or near-real-time to match the user's specific interpupillary distance and eye relief, transforming a static design into a dynamic adaptive system that optimizes performance for each user.
2Ease of manufacture
If HMDs use fixed optical configuration, then manufacturing is simplified, but users experience optical distortions due to variations in interpupillary distance and eye relief
Solution Approach 1:
The system changes key optical parameters (such as lens position, focal length, or eye box location) based on the measured user anatomy. By adjusting these parameters to match the user's specific interpupillary distance and eye relief, the system maintains optical performance consistency across different users while starting from a simplified fixed manufacturing baseline.
Solution Approach 2:
The system incorporates a feedback loop where the illumination sources and image capture device measure the user's anatomical parameters, and this measurement feedback is used to adjust the optical configuration. This closed-loop approach ensures that the optical system adapts to each user's unique anatomy, maintaining high reliability and consistent optical performance without requiring complex manufacturing variations.
3Reliability
If HMDs add measurement and adjustment mechanisms, then optical distortions are reduced, but device complexity increases
Solution Approach 1:
The illumination sources and image capture device serve multiple functions: they measure the user's anatomical parameters (interpupillary distance and eye relief) and may also be used for other HMD functions such as tracking or environmental sensing. This multi-functionality reduces the need for separate dedicated measurement components, thereby limiting the increase in device complexity while still achieving improved optical alignment accuracy.
Solution Approach 2:
The patent combines the measurement function with the existing HMD structure by integrating illumination sources and an image capture device into the headset itself. Rather than adding separate external measurement equipment, the system merges the measurement capability with the display and tracking components, achieving accurate optical alignment while minimizing the increase in overall device complexity.
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 effectively determines and adjusts for individual user anatomies, improving the alignment of the user's eyes with the HMD's optics, thereby reducing optical distortions and enhancing the overall VR experience.
Implementation Method 1
the image capture device captures images of light from the illumination sources reflected by the surface of the user's eye. Hence, the image capture device captures images of light emitted from the illumination sources that is reflected by the cornea of the user's eye.
Data Source
AI summary
A virtual reality headset includes multiple illumination sources emitting light towards a user's eye and an image capture device capturing light reflected by the user's eye. The image capture device captures images of light from the illumination sources reflected by the user's corneas when the user looks at a specific location in the virtual reality headset. Based on locations of light having at least a threshold intensity in the captured images, the position of the center of user's eye's pupil is determined in three dimensions and used to determine a distance between the center of user's eye's pupil and a reference point relative to the illumination sources. Distances between centers of pupils of the user's eyes and reference points are used to determine a distance between the centers of the pupils of the user's eyes and a distance from the corneas to an optical system of the headset.