Inkjet-Printed Microlenses for Solar Cells
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Solution Overview
Problem
The existing methods for fabricating microlenses for solar cells are complex and costly, requiring multiple steps and expensive equipment, which increases the fabrication time and cost.
Innovation Solution
A method involving the formation of a self-assembly monolayer with strong hydrophobicity, followed by jetting and drying of transparent ink droplets with solvents of different boiling points to create microlenses, simplifying the process and reducing costs while improving light collecting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithographic process is used to fabricate microlens, then microlens can be formed with controlled shape, but fabrication cost and complexity increase due to expensive photo mask and exposure apparatus
Solution Approach 1:
The inkjet printing system automatically forms microlenses by depositing photoresist material and using thermal energy to self-reflow and self-assemble the material into lens shapes, eliminating the need for external photo masks and complex exposure apparatus while maintaining shape control
Solution Approach 2:
The patent replaces the mechanical photolithographic system (photo mask, exposure apparatus) with a thermal field-based system where thermal energy from the substrate or environment causes the deposited photoresist to automatically reflow and form microlens shapes through surface tension and capillary effects
2Manufacturing precision
If photolithographic process is used to fabricate microlens, then microlens can be formed with controlled shape, but fabrication time increases due to multiple steps including coating, exposure and development
Solution Approach 1:
The patent combines multiple photolithographic steps (photoresist coating, pattern formation, and microlens shaping) into a single inkjet printing and thermal processing step, where the deposited material automatically forms both the pattern and the microlens shape through thermal reflow
Solution Approach 2:
The inkjet printing process deposits photoresist material in the final microlens pattern configuration from the beginning, and the subsequent thermal processing simultaneously performs both patterning and shape formation, eliminating the need for sequential steps required in traditional photolithography
3Reliability
If traditional microlens fabrication method is used, then microlens can be formed, but fabrication cost increases due to expensive equipment and materials
Solution Approach 1:
The patent uses inexpensive consumable materials such as standard inkjet photoresist inks and common substrate materials, replacing expensive reusable equipment like photo masks and specialized exposure apparatus, thereby significantly reducing fabrication cost while maintaining microlens quality
Solution Approach 2:
The inkjet printing system serves multiple functions: it deposits photoresist material, defines microlens patterns, controls microlens shapes through deposition parameters, and enables fabrication on various substrate types, replacing multiple specialized equipment functions required in traditional photolithography
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 reduces fabrication time and cost while enhancing light collecting efficiency and photoelectric performance by forming microlenses with controlled profiles that maximize light collection and path length through inner total reflection.
Implementation Method 1
a light collecting means on the second transparent electrode, wherein the light collecting means includes a self assembly monolayer having a strong hydrophobicity and a plurality of microlenses having a hydrophilicity on the self assembly monolayer
Implementation Method 2
the resin pattern 25 (of FIG. 1B) is heated and reflows in a heat treatment apparatus to become a microlens 30
Implementation Method 3
a light collecting means that concentrates the light of the sun and irradiates the light onto the surface of the solar cell
Implementation Method 4
maximize light collection and path length through inner total reflection
Data Source
AI summary
Disclosed is a method of fabricating a microlens. The method includes forming a self assembly monolayer having a strong hydrophobicity on a substrate; forming a plurality of ink droplets on the self assembly monolayer by jetting a transparent ink using an inkjet apparatus, the transparent ink including a first solvent having a first boiling point, a second solvent having a second boiling point lower than the first boiling point and a silicon oxide (SiOx) solid material dispersed in the first and second solvents; and drying the plurality of ink droplets.