OLED Bottom Electrode Layout for Uniform Ink-Jet Emission
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Solution Overview
Problem
The existing methods for manufacturing organic light-emitting diodes (OLEDs) using ink-jet printing result in nonuniform light emission due to ink climbing onto pixel defining layers, causing uneven thickness of the organic functional layer, leading to higher brightness at the central portion and lower brightness at the peripheral edges of pixels.
Innovation Solution
Incorporating shape memory alloy materials in the first pixel electrodes, which protrude during the drying process to redirect ink towards the second pixel electrodes, ensuring a uniform thickness of the organic functional layer across the pixel region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ink-jet printing method is used to manufacture OLEDs, then manufacturing efficiency and area coverage are improved, but the organic functional layer thickness becomes nonuniform due to ink climbing onto pixel defining layers
Solution Approach 1:
The first pixel electrode is prepared in advance with a shape that enables it to protrude during the drying process. This preliminary structural design allows the electrode to automatically redirect climbing ink toward the second pixel electrode during ink-jet printing, thereby preventing thickness nonuniformity while maintaining high manufacturing efficiency
Solution Approach 2:
The first pixel electrode is designed to dynamically change its shape during the drying process by protruding upward. This dynamic shape change enables the electrode to actively redirect the climbing ink flow toward the second pixel electrode, ensuring uniform organic functional layer thickness while preserving the benefits of ink-jet printing
2Manufacturing precision
If first pixel electrode is designed to protrude during drying process, then organic functional layer thickness uniformity is improved, but device structure complexity increases
Solution Approach 1:
The material composition of the first pixel electrode is changed to include a shape memory alloy or material with thermal expansion properties. This parameter change enables the electrode to automatically protrude during the drying process when exposed to heat, redirecting climbing ink without requiring complex mechanical structures or additional control systems
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 ensures uniform light emission by maintaining a consistent thickness of the organic functional layer, addressing the issue of nonuniform brightness and enhancing the overall light-emitting performance of OLEDs.
Implementation Method 1
each of the plurality of first pixel electrodes includes a shape memory alloy material. the shape memory alloy material has a property of forming a protrusion at a temperature at which a drying process of ink-jet printing is performed
Data Source
AI summary
There is provided an organic light-emitting diode including: a pixel defining layer on a substrate and having a plurality of openings for defining pixel regions, wherein each pixel region is a region including one pixel therein; a plurality of first pixel electrodes on the substrate and in the plurality of openings, respectively, each first pixel electrode being at a peripheral portion of a corresponding opening adjacent to the pixel defining layer; and a plurality of second pixel electrodes on the substrate and in the plurality of openings, respectively, each second pixel electrode being at a central portion of the corresponding opening. Each first pixel electrode is between the pixel defining layer and a corresponding second pixel electrode, and the plurality of first pixel electrodes and the plurality of second pixel electrodes are in a same layer. Each first pixel electrode includes a shape memory alloy material.