Waveguide Edge Photovoltaics for Light Recycling and Reflection Control
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Solution Overview
Problem
Waveguide-based near-eye display systems face issues with light reflection at the edges, leading to reduced image quality and efficiency, particularly with high refractive index substrates where traditional edge blackening techniques are ineffective due to refractive index mismatch.
Innovation Solution
Incorporating photovoltaic devices at the edges of the waveguide, fabricated using doped semiconductor materials with a refractive index matching the substrate, to absorb light and convert it into electrical power, thereby reducing reflection and improving image quality and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional edge blackening techniques are used, then light reflection is reduced, but they are ineffective with high refractive index substrates due to refractive index mismatch
Solution Approach 1:
The patent changes the refractive index parameter of the edge treatment material to match high refractive index substrates. By using photovoltaic materials with refractive indices tailored to match specific substrate materials (e.g., silicon carbide, lithium niobate, rutile, zinc sulfide, zinc selenide), the invention makes edge blackening effective for previously incompatible high-index materials.
Solution Approach 2:
The patent employs composite photovoltaic materials that combine light-absorbing properties with refractive index matching capabilities. These composite materials integrate the function of edge blackening with refractive index compatibility, enabling effective light reflection reduction in high-index waveguide substrates where traditional single-material approaches fail.
2Object-affected harmful factors
If photovoltaic devices are used to absorb light at edges, then light reflection is reduced and electrical power is generated, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by using photovoltaic materials that simultaneously perform edge blackening (reducing light reflection) and electrical power generation. This single component replaces what would traditionally require separate edge coating and power generation systems, thereby reducing overall device complexity while achieving multiple benefits.
Solution Approach 2:
The invention merges the edge blackening function with photovoltaic power generation into a single integrated component. By combining light absorption for reflection reduction with electrical energy conversion in the same edge structure, the patent eliminates the need for separate systems and simplifies the overall device architecture.
3Loss of energy
If photovoltaic devices are deposited on broadside surface or sidewalls, then light absorption is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by depositing photovoltaic materials specifically at the waveguide edges (sidewalls and/or broadside surfaces) rather than uniformly across the entire waveguide. This localized deposition targets the specific regions where light reflection occurs, improving absorption efficiency while minimizing the total material required and reducing manufacturing complexity compared to full-surface coating.
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 photovoltaic devices effectively reduce light reflection, enhance image contrast, and convert incident light into usable electrical power, improving the overall performance and efficiency of the waveguide display while minimizing light leakage into the environment.
Implementation Method 1
the photovoltaic device configured to convert at least a portion of the display light that reaches the edge of the waveguide into electrical power
Implementation Method 2
absorbing and converting light incident on edges of the waveguide into electric power
Data Source
AI summary
A waveguide display includes a waveguide configured to transport display light visible to human eyes, a coupler formed on a broadside surface of the waveguide and configured to couple portions of the display light out of the waveguide at one or more regions of the waveguide, and a photovoltaic device at an edge of the waveguide, the photovoltaic device configured to convert at least a portion of the display light that reaches the edge of the waveguide into electrical power.