Automatic IPD Alignment in Near-Eye Displays
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Solution Overview
Problem
Near-eye display devices often cause visual discomfort due to misalignment of the user's pupils with the optical axes, as the inter-pupillary distance (IPD) varies among individuals, leading to suboptimal collimated light alignment and resulting in eye strain.
Innovation Solution
A system and method for automatically aligning a see-through, near-eye mixed reality display device with a user's IPD by using gaze detection elements and sensors to determine the alignment of each pupil with its respective optical axis, and adjusting the display device's optical systems to ensure proper alignment, accommodating both symmetrical and asymmetrical IPDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the optical axes are positioned at a fixed distance suitable for one wearer, then the collimated light alignment is optimized for that user, but users with different IPD experience visual discomfort and eye strain
Solution Approach 1:
The patent implements movable support structures that allow the display optical systems to be dynamically repositioned relative to each other. This enables the optical axes to be adjusted to match different users' IPD measurements, transforming a static fixed-distance system into a dynamic adaptive system that maintains optimal collimated light alignment across multiple users with varying inter-pupillary distances
Solution Approach 2:
The system automatically adjusts the physical distance between the two display optical systems based on measured IPD parameters. By changing this spatial parameter, the optical axes are repositioned to align with each user's specific pupil separation, thereby resolving the contradiction between fixed manufacturing precision and variable user adaptability
2Manufacturing precision
If manual IPD adjustment is implemented, then users can achieve proper alignment, but the complexity of operation and setup increases
Solution Approach 1:
The system incorporates automatic IPD measurement and adjustment functionality that performs alignment without requiring user intervention. Sensors capture images of the user's pupils, the processor automatically calculates the IPD, and the movable support structures are actuated to position the optical axes in alignment with the measured pupils, eliminating manual adjustment operations entirely
Solution Approach 2:
The system uses sensors to capture real-time data about pupil positions and continuously monitors alignment status. This feedback loop allows the processor to determine whether proper alignment has been achieved and to make necessary adjustments automatically, replacing complex manual alignment procedures with an automated sensing-and-adjustment cycle
3Measurement precision
If gaze detection elements and sensors are added for automatic IPD measurement, then alignment accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent integrates multiple functions into existing components: the display optical systems serve both their primary display function and as mounting structures for gaze detection elements; the processors that already handle display rendering are extended to also perform IPD measurement calculations and alignment control; the movable support structures serve both positioning functions and act as the adjustment mechanism. This multi-functionality approach adds measurement and adjustment capabilities while minimizing the addition of separate dedicated components
Data Source
AI summary
The technology provides for automatic alignment of a see-through near-eye, mixed reality device with an inter-pupillary distance (IPD). A determination is made as to whether a see-through, near-eye, mixed reality display device is aligned with an IPD of a user. If the display device is not aligned with the IPD, the display device is automatically adjusted. In some examples, the alignment determination is based on determinations of whether an optical axis of each display optical system positioned to be seen through by a respective eye is aligned with a pupil of the respective eye in accordance with an alignment criteria. The pupil alignment may be determined based on an arrangement of gaze detection elements for each display optical system including at least one sensor for capturing data of the respective eye and the captured data. The captured data may be image data, image and glint data, and glint data only.