Head-Mounted Display Optical Alignment via Eye-Tracking Feedback
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Solution Overview
Problem
Head-mounted devices face misalignment issues due to exposure to stress or abuse, such as drop events, which affect the alignment of optical modules and compromise image presentation quality.
Innovation Solution
The device uses eye characteristic measurements, including interpupillary distance, eye opening angle, and cornea diameter, as reference points to detect misalignment. It employs optical module position sensors via electrode arrays and guide rails to adjust optical module positions, and control circuitry performs image warping to compensate for detected misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical modules are made adjustable along guide rails, then alignment adaptability is improved, but device complexity increases
Solution Approach 1:
The optical modules are made dynamically adjustable along guide rails through positioners, allowing the system to adapt to misalignment conditions while maintaining a relatively simple overall structure. The dynamic adjustment capability enables the system to compensate for stress-induced misalignment without requiring a completely complex redesign.
2Measurement precision
If eye characteristic measurements are used to detect misalignment, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system uses the user's own eye characteristics as reference points for detecting misalignment, eliminating the need for external calibration tools or complex alignment procedures. The eye characteristics serve as inherent reference markers that the system can measure and use for self-diagnosis of alignment issues.
Solution Approach 2:
The system continuously measures eye characteristics and uses this feedback to detect misalignment conditions. The measured eye characteristics are compared against reference values to determine whether misalignment has occurred, enabling real-time detection and compensation.
3Manufacturing precision
If image warping is performed to compensate for misalignment, then image quality is maintained, but processing time increases
Solution Approach 1:
The system performs image warping operations proactively when misalignment is detected, rather than waiting for user complaint or periodic maintenance. By detecting misalignment through eye characteristic measurements and immediately applying compensation, the system maintains image quality without requiring lengthy recalibration procedures.
Data Source
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AI summary
A head-mounted device may have optical modules (optical assemblies) that are slidably coupled to guide rails and that are positioned using respective left and right positioners. Each optical module may have a display configured to display an image in a respective eye box through a lens. A camera may be provided in each optical module. The cameras of the device may be used to measure eye characteristics such as eye-opening angle, eye lid opening size, cornea diameter, and interpupillary distance and these characteristics may be used in measuring optical module position changes over time. The device may also have optical module position sensors based on electrode arrays that are contacted by optical module electrodes on the optical modules. Control circuitry can perform image warping operations to ensure that displayed images are compensated for measured changes in optical module position.