Holographic Waveguide Light Management for AR Displays
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Solution Overview
Problem
Existing waveguide technologies face challenges in efficiently directing light within specific wavelength bands for applications like wearable heads-up displays, where precise light management is required for augmented reality.
Innovation Solution
The use of holographic incouplers and outcouplers, which are configured to be either transmissive or reflective, allows for the selective redirection of light within narrow wavebands within the waveguide, enabling efficient light propagation and display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional waveguide technologies are used, then light can be directed within the waveguide, but the efficiency and precision of light management within specific wavelength bands is insufficient
Solution Approach 1:
The waveguide incorporates different structural regions with distinct optical properties: coupling regions with holographic elements for selective wavelength coupling, and propagation regions optimized for total internal reflection. This local differentiation enables precise light management for specific wavelength bands while maintaining high propagation efficiency.
Solution Approach 2:
The patent utilizes wavelength-dependent optical parameters by designing holographic coupling elements with specific grating periods and orientations that resonate with particular wavelength bands. This allows selective coupling of desired wavelengths while rejecting others, achieving both precision and efficiency.
2Productivity
If holographic incouplers and outcouplers are used to selectively redirect light within narrow wavebands, then light propagation efficiency is enhanced, but the device complexity increases
Solution Approach 1:
Multiple holographic coupling elements for different wavelength bands are integrated into a single waveguide structure, combining their functions into one unified device. This merging approach achieves high light propagation efficiency for multiple wavelengths while avoiding the need for separate waveguides for each wavelength band.
Solution Approach 2:
The waveguide is designed as a multi-functional element that simultaneously performs total internal reflection for light guidance, wavelength-selective coupling via holographic elements, and acts as an optical combiner. This universality reduces the number of separate components needed, managing complexity while maintaining efficiency.
3Illumination intensity
If the waveguide is designed to manage specific wavelength bands precisely, then display quality is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent replaces mechanical alignment and physical structuring methods with holographic recording techniques. By using optical interference patterns to define the coupling elements, the system achieves precise wavelength selectivity through optical field interactions rather than mechanical precision, reducing manufacturing complexity while maintaining display quality.
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
This approach enables the waveguide to effectively direct light along different optical paths, enhancing the display quality and overlay capabilities in wearable heads-up displays by ensuring precise light management within specific wavelength bands.
Implementation Method 1
A waveguide is an optical element that directs light to travel within a volume of the waveguide by total internal reflection (TIR). That is, light within the waveguide which impinges on a boundary of the waveguide at an angle within a range of angles will be reflected back into the waveguide
Implementation Method 2
A waveguide typically includes an incoupler, which receives light from a light source and redirects the received light into the volume of the waveguide at an angle within the range of angles required for total internal reflection
Implementation Method 3
A waveguide can also include an outcoupler, which receives light from within the waveguide and redirects the light to travel at an angle outside of the range of angles required for total internal reflection. Thus, light traveling within the waveguide which impinges on the outcoupler can be redirected to exit the volume of the waveguide
Implementation Method 4
Waveguides can be combined with or incorporated into a transparent carrier material to form an optical combiner to allow light from the environment outside the waveguide to travel through the waveguide and to be 'combined' with light traveling within the waveguide
Data Source
AI summary
A waveguide including at least a first photopolymer layer and a second photopolymer layer having a barrier layer therebetween and a first transparent layer and second transparent layer overlaying the first and second photopolymer layers, respectively. The waveguide can further include at least one holographic incoupler and at least one holographic outcoupler, each configured to be responsive to light within a first waveband and unresponsive to light outside of the first waveband, and further configured to be transmissive or reflective.