Waveguide Coatings for Uniform Intensity Distribution
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Solution Overview
Problem
Current augmented reality display systems using optical waveguides face challenges in replicating images with uniform intensity distribution, leading to non-uniformities and artifacts due to multiple-loop interference and polarization issues.
Innovation Solution
The use of a planar optical waveguide with an input-coupler, intermediate-component, and output-coupler, along with an adjacent planar optical component such as a liquid crystal polymer (LCP) coating or mismatched index of refraction substrate, to perform pupil expansion and ensure a uniform intensity distribution by mitigating multiple-loop interference and optimizing polarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an optical waveguide is used to replicate images in augmented reality displays, then the display functionality is achieved, but non-uniform intensity distribution and artifacts occur due to multiple-loop interference and polarization issues
Solution Approach 1:
A polarization compensating plate is introduced as an intermediary component between the waveguide and the display engine. This plate compensates for polarization changes accumulated during light propagation through the waveguide, thereby reducing polarization artifacts and improving intensity distribution uniformity without altering the core waveguide structure
Solution Approach 2:
The patent modifies optical parameters by introducing a polarization compensating plate with specific optical properties (different index of refraction from the waveguide substrate). This changes the polarization state of light in a controlled manner to counteract the harmful polarization effects generated by multiple internal reflections within the waveguide
2Reliability
If multiple-loop interference is present in the waveguide system, then light propagation through the waveguide is achieved, but non-uniformities and artifacts are generated in the output image
Solution Approach 1:
The polarization compensating plate serves as a mediator that intervenes in the light propagation path to counteract the effects of multiple-loop interference. By compensating for polarization changes, it reduces the interference patterns and artifacts that would otherwise degrade image quality
Solution Approach 2:
The patent converts the harmful polarization effects caused by multiple-loop interference into a beneficial outcome by using a polarization compensating plate. The plate introduces controlled polarization changes that counterbalance the unwanted polarization artifacts, effectively transforming the problem into a solution
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 configuration achieves a substantially uniform intensity distribution in the output light, reducing non-uniformities and artifacts, thereby enhancing the image quality in augmented reality displays.
Implementation Method 1
The input-coupler couples light corresponding to the image into the bulk-substrate
Implementation Method 2
light corresponding to the image, which travels from the input-coupler to the output-coupler
Implementation Method 3
an adjacent planar optical component configured to provide a more uniform intensity distribution... comprises at least one of a liquid crystal polymer (LCP) coating or substrate, or a coating or substrate that has an index of refraction that is different than an index of refraction of the bulk-substrate
Implementation Method 4
The intermediate-component performs horizontal or vertical pupil expansion and directs the light corresponding to the image towards the output-coupler. The output-coupler performs the other one of horizontal or vertical pupil expansion
Data Source
Figure 1A~1C
Figure 2
Figure 3~4
AI summary
An apparatus for use in replicating an image associated with an input-pupil to an output-pupil includes a planar optical waveguide (700) including a bulk-substrate (106), and also including an input-coupler (112), an intermediate-component (114) and an output-coupler (116). The input-coupler (112) couples light corresponding to the image into the bulk-substrate (106) and towards the intermediate-component (114). The intermediate-component (114) performs horizontal or vertical pupil expansion and directs the light corresponding to the image towards the output-coupler (116). The output-coupler (116) performs the other one of horizontal or vertical pupil expansion and couples light corresponding to the image, which travels from the input-coupler (112) to the output-coupler (116), out of the waveguide. The apparatus further includes an adjacent planar optical component (702) to provide a more uniform intensity distribution compared to if the adjacent planar optical component were absent.