Adiabatic Planar Waveguide Coupler for Solar Cell Light Integration
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Solution Overview
Problem
Current technologies face inefficiencies in coupling light between high index and low index optical devices due to limitations in transparent, high index materials and reflection issues at interfaces, leading to low coupling efficiency and significant light loss.
Innovation Solution
A method involving the deposition of optical dielectric films with varying refractive index and thickness using a rotating table and RF bias, allowing for continuous and efficient coupling of light between devices with different optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high index transparent materials are used to improve light coupling efficiency, then coupling efficiency is improved, but material availability is limited and manufacturing complexity increases
Solution Approach 1:
The patent uses composite waveguide structures combining high index core layers (n>1.7) with lower index cladding layers, creating an integrated optical system that achieves efficient light coupling while using available materials in a structured configuration that delivers high index contrast benefits
2Illumination intensity
If high index materials with refractory temperatures are used to increase index of refraction, then index of refraction is improved, but material reliability deteriorates due to recrystallization and increased scattering
Solution Approach 1:
The patent changes the deposition parameters to achieve high index of refraction (n>1.7) through controlled physical vapor deposition processes rather than thermal processing, allowing high index materials to be deposited as amorphous films that maintain optical clarity without recrystallization
Solution Approach 2:
The patent utilizes phase transition control by depositing materials in vacuum as amorphous films that remain optically clear, avoiding the crystalline phase transitions that cause scattering losses when materials are heated to refractory temperatures
3Adaptability or versatility
If discrete optical elements such as lenses and gratings are used to transform optical characteristics, then coupling between devices with different étendue is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple optical functions (waveguiding, mode transformation, étendue matching, and light coupling) into a single integrated planar waveguide structure, eliminating the need for separate discrete optical elements and reducing overall device complexity while maintaining adaptability
Solution Approach 2:
The planar waveguide structure serves multiple functions simultaneously: it guides light, transforms optical modes, matches étendue between devices with different optical characteristics, and provides efficient light coupling, making the structure universally applicable to various coupling scenarios
4Ease of manufacture
If conventional deposition methods are used to deposit optical films, then manufacturing simplicity is maintained, but manufacturing precision of index of refraction and thickness uniformity deteriorates
Solution Approach 1:
The patent employs dynamic control during deposition by rotating the substrate table and controlling the relative motion between source targets and substrate, enabling uniform film deposition with precise control over thickness and index of refraction while maintaining process simplicity
Solution Approach 2:
The deposition process uses RF bias control and process monitoring to maintain precise control over film properties, ensuring uniform index of refraction and thickness while keeping the manufacturing process straightforward through automated feedback control
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 efficient and lossless coupling of light between high and low index devices, conserving étendue and transforming optical energy with minimal loss, thereby improving the integration of high index film layers into waveguide structures.
Implementation Method 1
mounting one or more wafers on a rotating table; continuously rotating the rotating table under one or more source targets
Implementation Method 2
biasing the one or more wafers with an RF bias; depositing an optical dielectric film on the one or more wafers
Data Source
AI summary
A solar cell includes a waveguide core for receiving light, a first layer formed on the waveguide core, a second layer formed on the first layer, a third layer formed on the second layer, first metalization coupled to the first layer, and second metalization coupled to the third layer. The first layer comprises a first optical film which varies in an index of refraction in a lateral direction between a first input end where the light is received and a first output end where the light is emitted. In some embodiments, wherein one or more of the first, second, or third layers has a tapered lateral thickness. In some embodiments, the first, second, and third layers form a PIN device. In some embodiments, the waveguide core has a first index of refraction that is lower than respective indexes of refraction for the first, second, and third layers.