Ocular Axis Tracking With Cornea–Retina Light Alignment
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Solution Overview
Problem
Existing image projection systems for virtual and augmented reality struggle with maintaining high-quality image brightness and contrast during eye movements due to the need for complex optical means to expand the small eye box, which often degrades image quality.
Innovation Solution
A method and system for tracking ocular axes, such as the CSCLR and optical axes, by using two narrow incident light beams to illuminate the cornea and retina, ensuring perpendicularity and spatial alignment, allowing accurate projection of virtual images onto the retina.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If optical means are used to expand the eye box, then the eye box size is increased, but the image brightness and quality are degraded
Solution Approach 1:
The system dynamically tracks eye movements and adjusts the projection position accordingly, eliminating the need for static optical expansion. The eye box is effectively expanded through real-time position correction rather than physical optical manipulation, preserving image quality while maintaining adequate retinal coverage.
Solution Approach 2:
The patent replaces complex optical expansion mechanisms with an electronic/software-based eye tracking and position correction system. Instead of using additional optical elements to physically expand the eye box, the system uses sensors and processing to detect eye position and computationally adjusts the projection, substituting mechanical/optical complexity with electronic control.
2Area of moving object
If optical means are used to expand the eye box, then the eye box size is increased, but the system complexity is increased
Solution Approach 1:
The patent replaces complex optical expansion mechanisms with an electronic/software-based eye tracking and position correction system. Instead of using additional optical elements to physically expand the eye box, the system uses sensors and processing to detect eye position and computationally adjusts the projection, substituting mechanical/optical complexity with electronic control.
Solution Approach 2:
The system extracts the eye tracking function from the optical path and handles it separately through sensors and processing units. By separating the eye tracking functionality from the projection optics, the system avoids adding complex optical elements while still achieving effective eye box expansion through computational methods.
3Illumination intensity
If eye tracking is implemented, then image quality is maintained, but the system complexity is increased
Solution Approach 1:
The eye tracking system serves multiple functions: it tracks eye position, determines gaze direction, and enables dynamic projection positioning. By making the tracking system multi-functional, the patent justifies the added complexity through the ability to maintain image quality and enable natural viewing without requiring separate systems for each function.
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
Enables high-quality, life-like virtual image projection by maintaining the position of virtual images on the retina with high accuracy, overcoming the limitations of complex optical expansion and ensuring consistent image brightness and contrast.
Implementation Method 1
a first incident light beam configured to be reflected from a cornea of an eye
Implementation Method 2
a second incident light beam configured to pass through the cornea and to be reflected from a retinal surface of the eye
Data Source
AI summary
Methods and systems for tracking an individual's eye, by tracking one or more ocular axes, are presented. The technique comprises the following: (i) illuminating the eye, over an area of the cornea extending over the pupil, with first and second incident light beams having a transverse cross sectional area smaller than a predetermined value with respect to an area of the pupil and propagating coaxially along a first optical path defined by central axes of the first and second incident light beams, wherein said first incident light beam is configured to be reflected from the cornea and said second incident light beam is configured to pass through the cornea and the pupil and to be reflected from a retina region of the eye; (ii) detecting respective first and second reflected light beams; (iii) adjusting the first optical path such that said first reflected light beam propagates along said first optical path and said second reflected light beam propagates along a second optical path having a predetermined spatial relationship with said first optical path whereby said predetermined spatial relationship is indicative of said ocular axis being along at least said first optical path; and (iv) tracking said ocular axis of the eye under changes in gaze direction of said eye by repeating (i) to (iii).