Discretized Emission Surface for AR Projection
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Solution Overview
Problem
Existing portable optical augmented reality data display systems suffer from diffraction effects and limited emission point density, leading to degraded image contrast due to spatial periodic emission point distributions and low emission point density, resulting in insufficient image quality on the user's retina.
Innovation Solution
An image projection device with a discretized emission surface, comprising waveguides, diffraction gratings, and electrodes, where the emission surface is divided into elementary emission zones with a densified and pseudo-randomly distributed emission points, and holograms are used to ensure angle- and phase-matched light waves, enhancing the emission point distribution and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If emission points are distributed according to spatial periodicities, then the device structure is simplified, but diffraction effects are generated that degrade image quality
Solution Approach 1:
The patent applies asymmetry by transitioning from periodic to aperiodic emission point distributions. The waveguide intersections with electrodes create emission points that are intentionally non-uniformly distributed, eliminating the spatial periodicities that cause diffraction effects while maintaining manufacturability through the inherent structure of the device components.
Solution Approach 2:
The patent changes the distribution parameter of emission points from periodic to aperiodic. By modifying how emission points are arranged in space (from regular intervals to random/irregular positions), the system eliminates diffraction artifacts while preserving the ability to form coherent light spots on the retina.
2Device complexity
If emission point density is limited, then the device complexity is reduced, but luminous halo and degraded contrast are produced
Solution Approach 1:
The patent applies local quality by ensuring that within each light spot region on the retina, there are multiple high-density emission points contributing light, while maintaining lower density between spots. This local concentration of emission points enhances contrast by strengthening the signal at intended projection locations without requiring uniform high density across the entire emission surface.
Solution Approach 2:
The patent transitions from considering only the 2D emission surface to including the 3D spatial distribution and angular characteristics of emitted light. By controlling emission in multiple dimensions (position, angle, phase), the system achieves high contrast through coherent addition of light waves from multiple emission points while suppressing unwanted diffraction patterns.
3Manufacturing precision
If emission points are subdivided into subsets with random distribution, then diffraction effects are reduced, but the density of emission points in each subset remains limited
Solution Approach 1:
The patent merges multiple waveguides and electrodes to create a large total number of emission points that are then distributed across multiple subsets. Each subset maintains random/aperiodic distribution for diffraction control, while the combined effect of all subsets provides high overall emission point density. The merging of multiple components (waveguides, electrodes, emission points) enables both low density per subset and high total density.
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 significantly improves image contrast and quality by increasing emission point density and optimizing the distribution, facilitating better image projection onto the retina while simplifying the manufacturing process.
Implementation Method 1
a set of Mx×My diffraction gratings rpq... Each diffraction grating rqp is positioned at the intersection of one of the waveguides gp and of one of the electrodes ep so as to form an emission point EPpq for a light wave
Implementation Method 2
holograms are used to ensure angle- and phase-matched light waves
Implementation Method 3
an array of nanometric light guides... a set of Mx waveguides gp
Data Source
AI summary
An image projection device for projecting an image onto an eye, includes an emission surface S comprising a set of waveguides, a set of diffraction gratings and a set of electrodes. Each grating is positioned at the intersection of one of the guides and of one of the electrodes so as to form an emission point for a light wave. The surface S is discretized into a plurality of elementary emission zones in a continuous mesh. Each zone comprises a subset of points distributed in a number nxij×nyij of emission point distributions. The points of one and the same distribution are configured to emit a resultant wave directed with a wave vector contained in an angular domain defined based on the number of zones discretizing the surface S and on the position of the zone on the surface S, the number nxij×nyij of distributions corresponding to the number of pixels of the image to be projected in said angular domain.