OLED Pixel Electrodes with Partition Walls for Uniform Drying
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Solution Overview
Problem
Existing organic light emitting diode (OLED) manufacturing techniques face challenges in achieving uniformity of the organic thin film, leading to uneven brightness and increased manufacturing complexity, particularly due to issues with droplet ejection and drying processes during the ink jet method.
Innovation Solution
A light emitting device with a substrate and pixel electrodes arranged in a matrix, featuring division portions with liquid repellency properties to control the formation and drying of the light-emitting function layer, allowing for divided light-emitting layers and varied drying start and end points across the substrate to prevent unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the EL layer is formed in a stripe shape by continuously scanning an ink jet head, then the processing time is reduced and manufacturing is facilitated, but unevenness in dryness occurs across pixel electrodes leading to uneven brightness
Solution Approach 1:
The patent divides the continuous EL layer into separate regions corresponding to individual pixel electrodes using partition walls. This segmentation prevents the propagation of drying unevenness across the entire stripe-shaped layer while still allowing continuous scanning deposition, thus resolving the contradiction between productivity and manufacturing precision.
2Ease of manufacture
If the EL layer is formed in a stripe shape, then manufacturing is facilitated by continuous scanning, but liquid droplets dry from the ends causing unevenness in dryness across pixel electrodes
Solution Approach 1:
Partition walls are introduced to divide the stripe-shaped EL layer into discrete pixel electrode regions. This allows continuous scanning manufacturing while preventing drying unevenness from affecting adjacent pixels, as each partitioned region dries independently from its designated end points.
Solution Approach 2:
The partition walls act as intermediary structures that physically separate the liquid droplets in adjacent pixel electrodes. This intermediary barrier prevents the drying process in one pixel from affecting neighboring pixels, thereby maintaining evenness in dryness across all pixel electrodes while preserving the efficiency of continuous scanning.
3Ease of manufacture
If organic thin film amount is not constant in respective organic EL elements, then manufacturing is simpler, but brightness becomes uneven across the display
Solution Approach 1:
The patent uses partition walls to segment the EL layer formation process into individual pixel electrode regions. This segmentation ensures that variations in organic thin film amount in one pixel do not affect adjacent pixels, allowing simpler manufacturing processes while maintaining brightness uniformity across the display through isolated pixel performance.
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 configuration enhances manufacturing efficiency and prevents uneven brightness by ensuring uniform drying and material distribution, improving the overall precision and cost-effectiveness of OLED production.
Implementation Method 1
the light-emitting function layer is formed by an ink jet method
Implementation Method 2
in the process of drying the ejected liquid or ink droplets
Data Source
AI summary
A light emitting device includes a substrate, a plurality of pixel electrodes arranged in a matrix on the substrate, and a counter electrode disposed opposite the plurality of pixel electrodes. Here, the plurality of pixel electrodes includes a first pixel electrode group including two or more of the plurality of pixel electrodes arranged continuously in a first direction and the first pixel electrode group includes a first pixel electrode and a second pixel electrode arranged to be adjacent to each other and a third pixel electrode and a fourth pixel electrode arranged to be adjacent to each other. A first division portion is disposed between the first pixel electrode and the second pixel electrode and a second division portion is disposed between the third pixel electrode and the fourth pixel electrode. At least one light-emitting function layer including a plurality of layers including a light-emitting layer is formed between two or more pixel electrodes located between the first division portion and the second division portion in the first pixel electrode group and the counter electrode to cover the two or more pixel electrodes located between the first division portion and the second division portion.