IR-Reflective Polymeric Particles for Photovoltaic Modules

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Solution Overview

Problem

Existing solutions for IR-reflective films in photovoltaic modules require complex layer structures and refractive index variations, which are inefficient and not effectively addressed for polymeric particles with specific optical properties.

Innovation Solution

Development of polymeric particles with controlled average diameters, Vicker's scale hardness, and refractive index differences to form films with a continuous polymeric phase, allowing for efficient IR reflection in photovoltaic modules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex layer structures with varying composition and refractive index are used to create IR-reflective films, then the optical filtering function is achieved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveoptical filtering functionVSAvoidlayer structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The film is segmented into a matrix phase and dispersed polymeric particles with different refractive indices. This segmentation allows the IR-reflective function to be achieved through the distributed particles rather than requiring complex layered structures, thereby simplifying the overall device architecture while maintaining optical filtering reliability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite material system consisting of a film-forming polymer matrix combined with polymeric particles having specific refractive index properties. This composite approach enables IR reflection functionality to be integrated into a single-layer film structure, eliminating the need for multiple layers with varying compositions and refractive indices

Inventive Principle:
Principle #40Composite materials

2Reliability

If polymeric particles with specific refractive index properties are used to form IR-reflective films, then the optical properties are improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveoptical propertiesVSAvoidparticle refractive index control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention changes the refractive index parameter of the polymeric particles to be within a specific range (different from the matrix polymer by 0.02-0.5) to achieve IR reflection. By controlling this physical parameter within defined boundaries rather than requiring exact values, the manufacturing precision requirement is made more practical while still achieving the desired optical properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The polymeric particles are given specific local quality characteristics (refractive index within a defined range) that differ from the surrounding matrix. This local differentiation at the particle level enables the overall film to exhibit IR-reflective properties without requiring precise control of the entire film structure, thus balancing optical performance with manufacturability

Inventive Principle:
Principle #3Local quality

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 solution enables the creation of IR-reflective films with improved optical properties, enhancing the performance and efficiency of photovoltaic modules by using polymeric particles with specific characteristics.

Implementation Method 1

an average refractive index difference measured from 800 nm to 2500 nm between the polymeric particles and the film-forming polymer is at least 0.04

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentUS20140221540A1IR-reflecting compositions
Publication Date: 2014.08.07 ROHM & HAAS CO

AI summary

A composition comprising multistage polymeric particles having an average particle diameter from 0.5 to 15 μm and a Vicker's scale hardness from 100 to 700 Kgf/mm2; and a film-forming polymer having Tg no greater than 80° C. The refractive index difference measured from 400 nm to 800 nm between the polymeric particles and the film-forming polymer is no greater than 0.02 and the average refractive index difference measured from 800 nm to 2500 nm between the polymeric particles and the film-forming polymer is at least 0.04.