Quantum Dot Patterning With Cured Resin for Fine Display Pixels
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Solution Overview
Problem
The existing methods for patterning quantum dots, such as photolithography and inkjet, face challenges like degradation due to heat and light, and limitations in forming fine patterns required for micro-LED applications, particularly with inkjet methods experiencing issues with viscosity, agglomeration, and ejection stability, leading to pattern defects and unevenness.
Innovation Solution
A method involving coating a mixture of quantum dots and a curable resin on a substrate, followed by ejecting a curing agent in a pattern shape using an inkjet method, curing the resin layer, and removing the uncured portion with a solvent, which allows for stable pattern formation and reduced quantum dot degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography is used for patterning quantum dots, then patterns can be formed through baking, exposing, and developing steps, but the quantum dots degrade due to heat and light effects resulting in deterioration of luminous efficacy
Solution Approach 1:
The patent extracts the harmful elements (heat and light exposure steps) from the photolithography process by replacing them with a UV-curable resin-based inkjet printing method. The curing agent is ejected in a pattern shape and cured with UV light only where needed, eliminating the need for extensive heat and light exposure that causes quantum dot degradation.
Solution Approach 2:
The patent replaces the thermal and optical processing steps of photolithography with a photopolymerization-based curing process. The uncured portion is removed with a solvent, leaving only the cured quantum dot patterns, thereby substituting harmful thermal/mechanical processing with a milder chemical curing process.
2Productivity
If inkjet method is used to eject quantum dot ink directly, then the number of steps is reduced and degradation due to heat and light is minimized, but the nozzle diameter becomes finer for 100 μm or less patterns causing clogging and ejection instability
Solution Approach 1:
The patent introduces a curable resin as an intermediary carrier for the quantum dots. Instead of ejecting quantum dot ink directly, the curable resin is ejected and cured to form a patterned layer that holds the quantum dots. This intermediary approach allows for stable ejection of higher viscosity material while achieving fine patterns through UV curing.
Solution Approach 2:
The patent changes the physical state and properties of the ejectable material from liquid quantum dot ink to a curable resin that can be ejected in a semi-solid state. The resin's viscosity and ejection characteristics are optimized for stable inkjet printing, and its ability to be cured with UV light enables fine pattern formation without requiring ultra-fine nozzles.
3Reliability
If inkjet method is used with curable resin and curing agent, then stable ejection is achieved with reduced clogging, but additional steps of ejecting curing agent and removing uncured portion are required
Solution Approach 1:
The patent combines multiple functions into the curable resin system: the resin serves as both the ejectable material and the pattern-defining material. The curing agent activation and uncured portion removal steps are integrated into a unified process that achieves both pattern formation and quantum dot fixation, reducing overall process complexity despite the additional curing step.
4Ease of manufacture
If quantum dots are dispersed in resin material and laminated as wavelength conversion film, then they can be incorporated into backlight unit, but pattern formation requires photolithography which degrades quantum dots
Solution Approach 1:
The patent performs preliminary pattern formation of the curable resin before incorporating the quantum dots. The curable resin is ejected in the desired pattern shape and cured in advance, creating a stable substrate that holds the quantum dots in their final positions. This preliminary action eliminates the need for post-quantum-dot pattern formation steps that would expose the quantum dots to degrading heat and light.
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 the stable formation of intended quantum dot patterns without inkjet method limitations and suppresses degradation, facilitating the production of optical devices, backlight units, and image display devices with improved luminous efficacy and color filter functionality.
Implementation Method 1
ejecting a curing agent in a pattern shape on the resin layer by an inkjet method; performing a curing treatment to cure a portion of the resin layer where the curing agent was ejected
Implementation Method 2
removing an uncured portion of the resin layer with a solvent
Implementation Method 3
excitons generated upon light absorption are confined in nanosized region, so that energy level of the semiconductor crystal particles becomes discrete and band gap thereof changes depending on the particle diameter. Owing to these effects, fluorescence emission by the quantum dots is brighter and more efficient
Data Source
AI summary
A patterning method of quantum dots, the method includes the steps of coating with a mixture containing quantum dots and a curable resin on a substrate to obtain a resin layer, ejecting a curing agent in a pattern shape on the resin layer by an inkjet method, performing a curing treatment to cure the portion of the resin layer where the curing agent was ejected, and removing an uncured portion of the resin layer with a solvent.