Structured Electrode Redirects Light via Total Internal Reflection
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Solution Overview
Problem
Optical devices face significant light shadowing losses due to the presence of electrodes, which limits the amount of incident light reaching the active region, affecting device performance and efficiency, especially in applications requiring high optical transmission and electrical access.
Innovation Solution
The implementation of a structured electrode with a light-receiving surface that utilizes total internal reflection (TIR) to redirect light towards the active region, eliminating the need for patterning of the device material and allowing for broader wavelength compatibility, including UV to IR ranges, with options for flat, angled, or curved surfaces and anti-reflection coatings to enhance light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional planar electrodes are used in optical detectors, then electrical contact is achieved, but light shadowing losses increase significantly
Solution Approach 1:
The patent applies curvature to electrode surfaces by depositing metal layers on tilted substrates, creating angled or curved electrode topographies. This curvature redirects incident light away from the electrode shadow regions and toward the active detection area, reducing light shadowing losses while maintaining electrical contact functionality
Solution Approach 2:
The patent introduces a third dimension by tilting the substrate during electrode deposition, creating electrodes with vertical angles rather than flat planar surfaces. This dimensional change allows light to be redirected at specific angles to bypass electrode shadows and reach the active region, effectively adding a spatial dimension to light management
2Loss of energy
If transparent conductive oxides are used to reduce shadowing, then light transmission improves, but device operation speeds and responsivity decrease
Solution Approach 1:
The patent extracts the light-redirection function from the electrode material properties and implements it through geometric shape instead. By using angled metal electrodes to redirect light away from shadow regions, the invention eliminates the need for transparent conductive oxides, thereby maintaining high electrical conductivity and fast operation speeds while still achieving improved light transmission
3Loss of energy
If periodically patterned electrodes are used for plasmon enhanced transmission, then light transmission improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies local quality by creating specific angled regions only where needed for light redirection, rather than implementing complex periodic patterns across the entire electrode structure. The angled surfaces are localized to the electrode topography created by substrate tilting, providing targeted light management with simpler manufacturing
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 significantly increases the amount of incident light reaching the active region, improving device performance by minimizing shadowing losses and enabling faster and more efficient operation across a broad spectral range with reduced electrode resistance.
Implementation Method 1
The implementation of a structured electrode with a light-receiving surface that utilizes total internal reflection (TIR) to redirect light towards the active region
Implementation Method 2
with options for flat, angled, or curved surfaces and anti-reflection coatings to enhance light transmission
Data Source
AI summary
An optical device including a shaped electrode on a substrate thereof utilizes total internal reflection to provide improved transmission of electromagnetic radiation (‘light’) to the substrate compared to standard electrode designs that involve flat electrode surfaces. Redirection of incident light by a tilted or otherwise shaped contact or material added on the contact provides otherwise reflected light to an open surface region of the substrate. Optional plasmon mediated focusing of incident p-polarized light may be realized.