Stepped Light Guide Layout for High-Concentration Light Collection
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Solution Overview
Problem
Conventional light guide systems for concentrated photovoltaic (CPV) applications suffer from light loss and étendue dilution due to interactions with light injection elements, which hinder efficient light propagation and concentration.
Innovation Solution
A light guide system with stepped light injection elements and a lenslet array, where the injection elements are staggered in planes parallel to the side-end surface, allowing for optimized light propagation and concentration by redirecting light without obstruction, and incorporating a low-index TIR layer for total internal reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light injection elements are used to concentrate light in conventional light guide systems, then light concentration is achieved, but light loss and étendue dilution occur due to interactions with the injection elements
Solution Approach 1:
The patent transitions from conventional planar light injection elements to a three-dimensional stepped light guide structure. The stepped configuration creates multiple propagation paths through vertical and horizontal steps, allowing light to be concentrated and transported without the losses associated with traditional injection elements. This dimensional transformation enables light concentration while avoiding étendue dilution by providing alternative propagation routes through the stepped geometry.
2Ease of operation
If conventional light injection elements are used, then light can be injected into the light guide, but light propagation is hindered and obstruction occurs
Solution Approach 1:
The light guide is segmented into multiple stepped sections with vertical and horizontal steps. This segmentation creates distinct propagation zones that guide light efficiently through the structure. Each step acts as an independent light redirecting element, allowing light to progress through the guide without obstruction while maintaining propagation efficiency. The segmented approach simplifies the overall light transport mechanism compared to conventional injection elements.
3Illumination intensity
If stepped light injection elements are implemented, then light concentration ratio is improved, but manufacturing complexity increases
Solution Approach 1:
The stepped light guide structure employs curved transition surfaces between steps rather than sharp angular transitions. These curved surfaces facilitate smoother light propagation and reduce manufacturing challenges associated with precise angular alignment. The curvature allows for more tolerant manufacturing processes while maintaining the high concentration ratio benefits of the stepped configuration.
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 system enhances light concentration and minimizes losses by positioning injection facets to avoid obstruction, achieving higher concentration ratios and maintaining a thin profile, with nominal system efficiency of 94% and potential for higher concentrations with secondary concentrators.
Implementation Method 1
incorporating a low-index TIR layer for total internal reflection
Data Source
AI summary
A light guide includes a light guide layer having a transversely oriented side-end surface that forms a primary output aperture (exit) for light traveling in a forward propagation direction out of the end surface of the light guide (for, e.g., CPV applications) and, which forms a primary input aperture (entrance) for light traveling in a rearward propagation direction into the end surface of the light guide (for, e.g., illuminator applications), and a first plurality of light injection elements stepped (staggered) in a forward light propagation direction in a first plane along lines parallel to the side-end surface or clocked (tilted) about a y-axis in a z-axis-light propagation direction in a respective first plane, wherein the light injection elements are disposed along parallel lines normal to the side-end surface. The light guide component may further comprise at least a second plurality of light injection elements stepped in at least second plane. A light guide system includes a component light guide, a lenslet array disposed adjacent a top surface of the light guide, and a light-transmitting, TIR medium layer disposed immediately adjacent at least one of the top and bottom surfaces of the light guide.