Optical Sight Eyebox Adjustment Using Exit Pupil Tracking
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Solution Overview
Problem
Magnified telescopic sights suffer from small exit pupil size, making it difficult for operators to maintain their eye within the effective eyebox, particularly under conditions of physical exertion or stress, leading to vignetting or loss of the observed image due to axial movement of the eye.
Innovation Solution
The optical sighting device automatically adjusts the eyebox depth by translating the aperture stop or adjusting the focus setting of a varifocal lens to align the real exit pupil with the user's eye along the optical axis, using a range-finder to measure the axial distance and control circuitry to compensate for continuous eye movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnified telescopic sights are used to achieve high magnification, then the viewing capability is improved, but the exit pupil size becomes very small making it difficult to maintain eye within the eyebox
Solution Approach 1:
The patent implements dynamic adjustment of the optical system to maintain a large exit pupil while achieving high magnification. The system continuously adapts the optical path and exit pupil positioning based on detected eye position, allowing the exit pupil to dynamically follow the user's eye movements rather than being fixed at a small location
Solution Approach 2:
The system uses eye position detection to provide feedback to the optical adjustment mechanism. The detected eye position information is used to automatically reposition the exit pupil and adjust the optical path, creating a closed-loop system that maintains optimal viewing conditions without requiring manual intervention
2Measurement precision
If the exit pupil size is kept small for high magnification, then the magnification performance is improved, but the eyebox depth becomes very small causing black-out effect due to axial eye movement
Solution Approach 1:
The patent implements dynamic adjustment of the optical system to maintain a large exit pupil while achieving high magnification. The system continuously adapts the optical path and exit pupil positioning based on detected eye position, allowing the exit pupil to dynamically follow the user's eye movements rather than being fixed at a small location
Solution Approach 2:
The system uses eye position detection to provide feedback to the optical adjustment mechanism. The detected eye position information is used to automatically reposition the exit pupil and adjust the optical path, creating a closed-loop system that maintains optimal viewing conditions without requiring manual intervention
3Area of stationary object
If the eyebox depth is kept small for wide apparent field of view, then the field of view is improved, but the stability requirement increases making it difficult to maintain visual contact under physical exertion
Solution Approach 1:
The patent implements dynamic adjustment of the optical system to maintain a large exit pupil while achieving high magnification. The system continuously adapts the optical path and exit pupil positioning based on detected eye position, allowing the exit pupil to dynamically follow the user's eye movements rather than being fixed at a small location
Solution Approach 2:
The system uses eye position detection to provide feedback to the optical adjustment mechanism. The detected eye position information is used to automatically reposition the exit pupil and adjust the optical path, creating a closed-loop system that maintains optimal viewing conditions without requiring manual intervention
4Measurement precision
If manual adjustment is used to achieve proper eye alignment, then the alignment precision can be improved, but the time required to achieve proper match increases significantly
Solution Approach 1:
The system performs automatic eye box adjustment without requiring manual intervention. The eye position detection and optical adjustment mechanisms work together to automatically align the exit pupil with the user's eye, eliminating the need for manual focusing and positioning that would otherwise be required
Solution Approach 2:
The system uses eye position detection to provide feedback to the optical adjustment mechanism. The detected eye position information is used to automatically reposition the exit pupil and adjust the optical path, creating a closed-loop system that maintains optimal viewing conditions without requiring manual intervention
Data Source
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AI summary
An optical sighting device includes an eyepiece positioned to receive optical radiation along an optical axis to produce a real exit pupil located remote from the eyepiece. The real exit pupil is positioned at an eye relief distance from the eyepiece along the optical axis. A digital signal processor determines an axial distance from the eyepiece to an eye positioned proximate the real exit pupil along the optical axis. An aperture stop is centered along the optical axis to direct the optical radiation in a direction of the eyepiece. The eye relief distance is based at least in part on a position of the aperture stop along the optical axis. The optical sighting device further includes an eye relief actuator to translate the aperture stop along the optical axis to null a spatial offset between the eye relief distance and the axial distance to the eye.