Directional Screen Projection with Optical Combiner for a Larger Eye Box
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Solution Overview
Problem
Existing augmented reality devices for projecting images onto the eye face challenges such as a small eye box and the use of mechanical scanning systems, which increase complexity and cost, and are not user-friendly due to varying interpupillary distances among users.
Innovation Solution
A device with a directional screen and optical combiner that emits divergent light waves, using a stack of light guides and diffraction gratings, coupled with electrodes, to form collimated light waves without mechanical components, allowing for a larger eye box and improved user comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical scanning system is used to project images onto the eye, then the device can form light beams scanning the holographic reflector, but the device complexity increases and cost increases due to moving components
Solution Approach 1:
The patent replaces the mechanical scanning system with an electro-optical system. Instead of using moving mirrors to scan light beams across the holographic reflector, the invention uses a light emitter (such as an LED or laser diode) that directly generates light beams that are modulated by electrodes to scan the holographic reflector. This substitution eliminates mechanical moving parts while maintaining the image projection capability, thereby reducing device complexity and cost.
2Ease of operation
If a mechanical scanning system is used to project images onto the eye, then the device can form light beams scanning the holographic reflector, but the cost increases due to mechanical components
Solution Approach 1:
The patent replaces the mechanical scanning system with an electro-optical system. Instead of using moving mirrors to scan light beams across the holographic reflector, the invention uses a light emitter (such as an LED or laser diode) that directly generates light beams that are modulated by electrodes to scan the holographic reflector. This substitution eliminates mechanical moving parts while maintaining the image projection capability, thereby reducing device complexity and cost.
3Volume of moving object
If a small eye box is used in the device design, then the device can be compact, but the device is not suitable for users with different interpupillary distances
Solution Approach 1:
The patent implements a dynamic eye box through the use of a light emitter with electro-optical modulation. The light emitter can be controlled to project images at different angular directions, allowing the eye box to adapt to users with different interpupillary distances. The system dynamically adjusts the light beam directions and intensities to maintain a usable eye box for various user configurations, making the device versatile while maintaining compact dimensions.
Solution Approach 2:
The patent changes the optical parameters (such as light beam direction, intensity, and convergence) to expand the effective eye box. By modulating the light emitter with electrodes, the system can adjust the parameters of the projected light beams to accommodate different user eye positions and interpupillary distances, thereby increasing adaptability without significantly increasing device volume.
4Adaptability or versatility
If a directional screen with divergent light waves is used, then the eye box can be enlarged, but the device requires precise optical coupling
Solution Approach 1:
The patent introduces an optical combiner as an intermediary element between the directional screen and the user's eye. The optical combiner receives divergent light waves from multiple pixels of the directional screen and combines them into collimated light waves that propagate towards the pupil of the eye. This intermediary component facilitates precise optical coupling by transforming the divergent light waves into a unified collimated beam, thereby enabling an enlarged eye box while maintaining manufacturing feasibility.
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 solution provides a compact, user-friendly device with an enlarged eye box, reducing mechanical complexity and cost, while maintaining image clarity and adaptability across different interpupillary distances.
Implementation Method 1
a light emitter, configured to emit light waves respectively along different emission axes
Implementation Method 2
an optical combiner, optically coupled to the light emitter, and configured to form, from each light wave emitted by the light emitter, a collimated light wave propagating towards the pupil of the eye
Implementation Method 3
the light emitter comprises a screen, comprising different pixels, each pixel being configured to emit a divergent light wave propagating around an emission axis
Implementation Method 4
the optical combiner is configured to receive each light wave emitted by a pixel and form a collimated light wave propagating towards a central position, corresponding to the center of the pupil of the eye
Data Source
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AI summary
A device for projecting an image onto an eye, the device comprising: - a light emitter, configured to emit light waves respectively along different emission axes; - an optical combiner, optically coupled to the light emitter, and configured to form, from each light wave emitted by the light emitter, a collimated light wave propagating towards the pupil of the eye; the device being characterized in that: - the light emitter comprises a screen, comprising different pixels, each pixel being configured to emit a divergent light wave propagating around an emission axis, the different pixels respectively emitting divergent light waves propagating respectively along different emission axes;The optical combiner is configured to receive each light wave emitted by a pixel and form a collimated light wave propagating towards a central position, corresponding to the center of the pupil of the eye.