Retinal Projection Optics With Pupil-Tracked Convergence Control
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Solution Overview
Problem
Existing image projection devices using Maxwellian view struggle to maintain image projection onto the retina when a user changes their gaze direction.
Innovation Solution
An image projection device with a scanning portion, imaging portion, identifying portion, and position control portion that adjusts the convergence point of light beams based on pupil position to align with the user's gaze, using a biaxial actuator to move a reflection portion and store control information for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a movable mirror is used to track eye movement, then the image can be projected onto the retina even when the user moves their gaze, but the device complexity increases
Solution Approach 1:
The patent replaces the mechanical movable mirror tracking system with an optical waveguide-based eyebox expansion system. Instead of mechanically moving mirrors to track eye movements, the system uses optical coupling between the waveguide and the user's eye to expand the effective eyebox, eliminating complex mechanical tracking components while maintaining retinal projection capability across different gaze directions.
2Device complexity
If the convergence point is fixed inside the user's eye, then the optical system is simple, but the image cannot be projected onto the retina when the user changes gaze direction
Solution Approach 1:
The patent implements a dynamic optical system where the waveguide's optical properties are adjusted based on detected eye movement. The system dynamically modifies the optical coupling between the waveguide and the user's eye to maintain proper light convergence on the retina even as the user changes gaze direction, transitioning from a static to a dynamic adaptation mechanism.
Solution Approach 2:
The system incorporates eye movement detection that provides feedback to control the optical coupling between the waveguide and the user's eye. This feedback mechanism allows the system to detect when the user moves their gaze and automatically adjusts the optical parameters to maintain proper retinal projection, creating a closed-loop control system.
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
Ensures continuous image projection onto the retina even as the user changes gaze direction, maintaining clear and focused imagery.
Implementation Method 1
an optical member provided between the emitting portion and the reflection portion and configured to convert each of the plurality of light beams into focused light to focus light at a focusing point in front of the emitting portion and then cause the light to enter the emitting portion as diffused light
Data Source
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AI summary
This image projection device (100) comprises: a projection unit (10) that includes a light source (11), a scanning unit (13) that causes a light beam emitted from the light source (11) to scan, and a projection optical system (20) that projects an image onto a retina (61) by causing a plurality of light beams, which are caused to scan by the scanning unit (13) and thereby emitted in different directions from the scanning unit (13), to converge at a convergence point (70) in an eye (60) of a user, and then projecting the converged light beams to the retina (61); an imaging unit (40) that captures an image of the eye (60) of the user; an identifying unit (34) that identifies the position of the pupil (62) in the captured image of the eye (60) of the user captured by the imaging unit (40); and a position control unit (32) that causes a component provided to the projection unit (10) that is capable of moving the position of the convergence point (70) to move and matches the position of the convergence point (70)to the pupil (62), on the basis of the position of the pupil (62) in the captured image identified by the identifying unit (34) and control information in which a plurality of points in an image captured by the imaging unit (40) and control values from when the convergence point (70) is positioned at the plurality of points are associated.