Meta Surface Deflector for AR Eyebox Expansion
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Solution Overview
Problem
Conventional augmented reality (AR) display devices, such as AR glasses, have a restricted eyebox due to the angular and wavelength selectivity of holographic or diffractive optical elements, making it cumbersome for users with varying eye gaps to share and use the same device, as the image is only visible when the user's eyes are accurately positioned at a specific point.
Innovation Solution
Incorporating a meta surface deflector that changes the deflection direction of light based on its polarization, allowing images of different polarizations to be focused at distinct positions, thereby expanding the eyebox and enabling a larger region of visibility by using a polarization-dependent meta surface deflector and a steering mechanism synchronized with an eye tracker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a holographic optical element or diffractive optical element is used in the combiner, then the image can be focused on the viewer's eyes, but the eyebox is restricted to one point making it cumbersome for users with various eye gaps to share and use one pair of AR glasses
Solution Approach 1:
The invention segments the eyebox into multiple regions by using a spatial light modulator to generate multiple light beams with different angles. Each light beam corresponds to a different eyebox region, allowing multiple users with different eye gaps to share the same device. The combiner is divided into multiple regions, each coupled with a specific light beam from the spatial light modulator.
Solution Approach 2:
The invention uses a spatial light modulator that can dynamically adjust and control multiple light beams with different angles and intensities. This dynamic control allows the system to adapt to different users' eye positions and gaps in real-time, expanding the effective eyebox from a single fixed point to multiple adjustable regions.
2Measurement precision
If the eyebox is greatly restricted to one point, then the image can be sharply focused, but the user must accurately position their eyes at a specific point and requires correction processes for different eye gaps
Solution Approach 1:
The combiner is designed to perform multiple functions by being divided into multiple regions, each coupled with a different light beam from the spatial light modulator. This multi-functional design allows the single combiner to serve multiple users with different eye gaps simultaneously, eliminating the need for separate devices or correction processes for each user.
Solution Approach 2:
The spatial light modulator automatically adjusts and controls multiple light beams to correspond to different user eye positions. The system self-adapts to different users without requiring manual correction or adjustment, making the device easy to use for multiple users with varying eye gaps.
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 effectively doubles the size of the eyebox, allowing for a wider range of user positions and reducing the need for precise alignment, enhancing user convenience and usability across different eye gaps.
Implementation Method 1
a meta surface deflector positioned between the image provider and the optical element to deflect the light, and change a deflection direction of the light according to a polarization of the light
Implementation Method 2
an optical element configured to focus the light from the image provider
Implementation Method 3
a spatial light modulator configured to modulate light according to image information
Data Source
AI summary
A display device including a meta surface is provided. The display device includes an image provider comprising a spatial light modulator configured to modulate light according to image information, wherein the image provider is configured to provide the light comprising the image information; an optical element configured to focus the light from the image provider; and a meta surface deflector positioned between the image provider and the optical element to deflect the light, and change a deflection direction of the light according to a polarization of the light so that a first position of the light of a first polarization focused by the optical element is different than a second position of the light of a second polarization orthogonal to the first polarization focused by the optical element.