Eye Tracking Optical Assembly for Binoculars
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Solution Overview
Problem
Conventional eye tracking apparatuses face challenges in accurately determining eye position due to unwanted reflections and reduced light transmission from ambient surroundings, especially when used in conjunction with secondary optical apparatuses like microscopes or goggles, which require disparate focus settings and can disrupt the user's view.
Innovation Solution
An eye tracking apparatus with an optical assembly that includes an eye viewing element to directly image the user's eye within their field of vision, relaying the image to a remote sensor via a long first imaging path, while a scene viewing element captures the scene image along a second path, allowing for minimal disruption and maintaining unobstructed light transmission. This setup uses relay lenses to extend the optical path and includes an optical combiner for coaxial alignment of imaging paths, reducing parallax errors and occupying a small portion of the user's field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a semi-transmissive optical combiner is used to capture eye images, then eye tracking is enabled, but unwanted reflections from ambient surroundings occur and light transmission from the scene is reduced
Solution Approach 1:
The optical system is segmented into separate functional paths: a first imaging path for capturing eye images and a second imaging path for capturing scene images. This segmentation allows each path to be optimized independently, with the eye imaging path using appropriate illumination and optics without compromising scene light transmission.
Solution Approach 2:
The eye imaging function is extracted from the scene viewing path. Instead of using a semi-transmissive combiner that compromises both paths, the invention uses a dedicated eye viewing element that captures only reflected light from the eye, completely separating the eye tracking function from the scene viewing function.
2Measurement precision
If the eye imaging sensor is placed close to the eye to capture eye images, then eye tracking is enabled, but the sensor disrupts the user's field of vision and impedes their view of the scene
Solution Approach 1:
The eye imaging sensor is positioned in a different spatial dimension relative to the eye - specifically, above or below the field of vision rather than within it. The optical assembly uses a folded optical path with relay optics to achieve this three-dimensional arrangement, allowing the sensor to be remotely located while maintaining accurate eye imaging capability.
3Adaptability or versatility
If conventional eye tracking apparatus is used with secondary optical apparatus, then eye tracking is attempted, but disparate focus requirements and eye relief issues arise
Solution Approach 1:
The optical assembly is designed with universal applicability to work with various secondary optical apparatus (microscopes, telescopes, goggles). The separated imaging paths and remote sensor positioning create a flexible system that can accommodate different focus requirements and eye relief specifications of various optical devices.
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 apparatus effectively tracks eye movement with minimal disruption to the user's view, allowing 100% light transmission and reducing parallax errors, making it suitable for use with secondary optical apparatuses by positioning sensors remotely and keeping optical components small, thus enhancing accuracy and usability.
Implementation Method 1
an eye viewing element adapted to directly image a user's eye from within the user's field of vision
Implementation Method 2
The optical assembly in typical embodiments will generally be elongate and may include a structural housing or casing
Data Source
AI summary
An eye tracking apparatus for monitoring a user's eye, for use in conjunction with secondary optical apparatus such as binoculars or night vision goggles. An optical assembly is adapted directly to image the eye from within the user's field of vision, and relay the image to a sensing element, which can be located outside the field of vision. Additionally the scene is imaged, also optionally from within the user's field of vision, which allows for scene imaging through the secondary optical apparatus. The optical assembly typically extends across the eyepiece of for example binoculars, and can be provided in a small form factor so as to interfere minimally with the view through the eyepiece. Both eye image and scene image can be relayed through the optical assembly, resulting in further space efficiencies.