Near-Eye Red Waveguide Placement and Thickness for Brightness
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Solution Overview
Problem
Conventional waveguide architectures for augmented reality displays face inefficiencies in coupling red light due to the use of separate waveguides for each visible color, leading to low brightness and color non-uniformity, particularly with uLED light engines that are inefficient at producing red light.
Innovation Solution
A near-eye display system employs a waveguide architecture with a separate waveguide for red light positioned closer to the user's eye, thicker than waveguides for blue and green light, and optimized with higher refractive index materials and grating characteristics to enhance coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If separate waveguides are used for each visible color (blue, green, red), then color separation and guidance are achieved, but red light coupling efficiency is low and brightness is reduced
Solution Approach 1:
The patent divides the waveguide system into separate waveguides for different color channels (blue, green, red), with each waveguide optimized independently. The red waveguide is specifically designed with enhanced coupling structures to improve red light extraction efficiency from the uLED source, directly addressing the low brightness and energy loss issues in conventional multi-color waveguide displays.
Solution Approach 2:
The patent applies different optical properties and structures to different parts of the system: the red waveguide has distinct coupling structures, thickness, and material properties compared to blue and green waveguides. This local optimization allows each waveguide to be tuned for its specific wavelength range, improving overall system brightness while minimizing energy loss in each color channel.
2Stability of the object's composition
If separate waveguides are used for each visible color, then color guidance is achieved, but color non-uniformity increases
Solution Approach 1:
By segmenting the waveguide system into separate color-specific waveguides, the patent enables independent optimization of each channel's optical properties. This segmentation allows precise control over color distribution and uniformity in each waveguide, compensating for the inherent complexity of managing multiple separate optical paths.
Solution Approach 2:
The patent employs parameter changes in the red waveguide design, including adjusted thickness, modified coupling grating parameters, and optimized material properties, to achieve uniform color output. These parameter adjustments are specifically tailored to compensate for the lower efficiency of red light generation in uLEDs, ensuring consistent color uniformity across the display.
3Loss of energy
If red waveguide is optimized with higher refractive index materials and increased thickness, then red light coupling efficiency improves, but device complexity increases
Solution Approach 1:
The patent applies enhanced structural characteristics (higher refractive index materials, increased thickness, specialized coupling gratings) specifically to the red waveguide where they are most needed, rather than uniformly across all waveguides. This localized optimization improves red light coupling efficiency while minimizing the overall complexity increase of the entire waveguide system.
Solution Approach 2:
The patent modifies specific parameters of the red waveguide (refractive index, thickness, grating depth) to optimize red light extraction. These parameter changes are carefully selected to maximize coupling efficiency improvements while maintaining manufacturability and avoiding excessive complexity in the overall device architecture.
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
Improves red light coupling efficiency and reduces color non-uniformity, enhancing the overall brightness and user experience of augmented reality displays.
Implementation Method 1
a first waveguide configured to guide red light to a user's eye and a second waveguide configured to guide at least one of blue light and green light to the user's eye
Implementation Method 2
the first waveguide includes nanostructures that comprise resin having a first refractive index and the second waveguide includes nanostructures that comprise resin having a second refractive index lower than the first refractive index
Data Source
AI summary
To enhance the efficiency of guiding red light to a user's eye, a near-eye display system employs a waveguide architecture that includes a separate waveguide for red light that is optimized through one or more of placement of the separate waveguide for red light within a waveguide stack, materials used for nanostructures or a substrate of the separate waveguide for red light, thickness of the separate waveguide for red light, and grating characteristics used for the separate waveguide for red light.