Variable Focus Lenses for Eye Relief–Aware AR Alignment
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Solution Overview
Problem
Existing augmented reality devices with variable focus lenses fail to accurately align the focal region with the user's visual axis due to insufficient consideration of eye relief, leading to reduced lens resolution and user fatigue.
Innovation Solution
An augmented reality device that uses eye tracking sensors to determine the position of the focal region based on eye relief, interpupillary distance, and gaze point, adjusting the refractive power of the variable focus lenses to improve alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the focal region position is determined using only gaze direction and interpupillary distance, then the alignment accuracy is insufficient, but adding eye relief measurement increases device complexity
Solution Approach 1:
The eye tracking sensor performs multiple functions: it tracks gaze direction, measures interpupillary distance, and determines eye relief by detecting the position of the eye relative to the lens. This multi-functionality approach improves alignment accuracy without adding separate measurement devices, thus resolving the contradiction between precision and complexity.
Solution Approach 2:
The patent uses the eye tracking sensor as an intermediary to indirectly measure eye relief. Instead of directly measuring the distance between the eye and lens, the system uses the sensor to detect eye position and calculates eye relief based on this position information, thereby achieving accurate alignment without complex direct measurement mechanisms.
2Reliability
If the focal region position is not accurately aligned with the visual axis, then vision correction is ineffective, but continuous adjustment increases processing time
Solution Approach 1:
The system performs preliminary alignment by determining the focal region position based on eye relief, gaze direction, and interpupillary distance before the user needs to view anything. This preliminary calculation ensures that the focal region is pre-positioned correctly on the visual axis, eliminating the need for continuous real-time adjustments and reducing processing time while maintaining high reliability.
3Manufacturing precision
If eye relief is not considered in focal region positioning, then lens resolution is reduced, but measuring eye relief adds measurement complexity
Solution Approach 1:
The eye tracking sensor is designed to measure multiple parameters including eye relief, gaze direction, and interpupillary distance simultaneously. By making the sensor multi-functional, the system achieves high lens resolution through accurate eye relief measurement without adding separate measurement devices or increasing overall measurement 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
Enhances the alignment of the focal region with the user's visual axis, improving vision correction, image quality, and reducing fatigue by considering eye relief in addition to gaze direction and interpupillary distance.
Implementation Method 1
an eye tracking sensor configured to emit light to eye of a user and detect a plurality of feature points based on light reflected by the eye of the user
Data Source
AI summary
Provided is an augmented reality device including a variable focus lens, an eye tracking sensor configured to emit light to eyes of a user, receive the light reflected by the eyes of the user, and detect a plurality of feature points based on the light reflected by the eyes of the user, and at least one processor configured to obtain information with respect to eye relief, which is a distance between the eyes of the user and the variable focus lens, based on position information of the plurality of feature points detected by the eye tracking sensor, obtain information with respect to a gaze point at which gaze directions of the eyes of the user converge, and an interpupillary distance of the eyes of the user, based on the plurality of feature points, and determine a position of a focal region of the variable focus lens based on the information with respect to the eye relief, the gaze point, and the interpupillary distance.