Inkjet LED Alignment Using Dual-Viscosity Coating Layers
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Solution Overview
Problem
The challenge in manufacturing ultra-small light emitting diodes at a microscale or nanoscale level is achieving precise alignment of these elements during the formation of display panels, particularly due to issues with settling time and misalignment when applying electric fields.
Innovation Solution
The use of an inkjet printing apparatus that applies solutions with different viscosities, where a first solution with higher viscosity is applied first, followed by a second solution containing light emitting elements, and an electric field is applied sequentially to align the elements effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single solution containing light emitting elements is applied directly, then the coating process is simple, but the alignment precision of ultra-small light emitting elements deteriorates due to rapid settling and misalignment
Solution Approach 1:
The coating process is segmented into two distinct stages: first applying a high-viscosity solution to establish a stable base layer, then applying a low-viscosity solution containing light emitting elements for precise alignment. This segmentation allows each stage to optimize for its specific function, resolving the contradiction between process simplicity and alignment precision.
Solution Approach 2:
The high-viscosity solution is applied in advance to create a stable foundation layer before introducing the light emitting elements. This preliminary action prepares the substrate to support subsequent elements without causing misalignment, enabling precise alignment while maintaining manufacturing efficiency.
2Manufacturing precision
If the viscosity of the solution is high to improve alignment stability, then the settling time increases, but the productivity decreases due to slower coating process
Solution Approach 1:
The coating process uses two solutions with different viscosities applied in sequence. The high-viscosity first solution provides stability and extended settling time for alignment, while the low-viscosity second solution maintains fast coating speed. This segmentation resolves the contradiction between alignment stability and coating speed.
Solution Approach 2:
The viscosity parameter is changed between the two solutions: the first solution has high viscosity for stability, while the second solution has low viscosity for speed. This parameter change allows the system to optimize for different requirements at different stages of the process.
3Manufacturing precision
If electric field is applied immediately after coating to improve alignment speed, then misalignment occurs due to insufficient settling time, but applying electric field later increases processing time
Solution Approach 1:
The high-viscosity solution is applied in advance to create a stable environment that naturally extends the settling time of light emitting elements. This preliminary stabilization allows the electric field to be applied at the optimal moment for alignment, achieving high accuracy without excessive processing time.
Solution Approach 2:
The viscosity parameter of the first solution is changed to high values, which naturally increases the settling time of particles. This parameter change extends the effective alignment window, allowing precise alignment to be achieved without rushing the process or applying electric field too early.
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 method enhances the alignment of ultra-small light emitting elements by increasing the settling time and reducing defects such as overlapping, resulting in improved manufacturing precision of display panels.
Implementation Method 1
applying an electric field to the work substrate
Implementation Method 2
the plurality of light emitting elements may be aligned so that the first semiconductor layer overlaps the first electrode and the second semiconductor layer overlaps the second electrode in a thickness direction
Data Source
AI summary
A display panel manufacturing method includes: applying a first solution onto a work substrate; applying, onto the first solution, a second solution including a plurality of light emitting elements; and applying an electric field to the work substrate. A viscosity of the first solution is different from a viscosity of the second solution.