OLED Emission Layer Formation via Electrostatic Spraying
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Solution Overview
Problem
Existing organic light-emitting display devices face challenges in achieving high efficiency emission due to interface deterioration and increased investment costs associated with manufacturing methods like nozzle printing and deposition, which require large spaces and are difficult to arrange in-line.
Innovation Solution
The use of an electrostatic spraying method to form organic light-emitting diodes (OLEDs) with a solubility process, where emission layers are formed by spraying charged liquid raw materials through a nozzle unit, allowing for the formation of thin film transistors and organic layers, including emission layers, hole injection layers, and electrodes, without the need for complex deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the deposition method is used to form intermediate layers, then the emission efficiency can be improved, but the solvent may dissolve the emission layer and deteriorate the interface characteristic
Solution Approach 1:
The patent introduces a barrier layer between the emission layer and the intermediate layer. This barrier layer acts as an intermediary that prevents the solvent from the intermediate layer from dissolving the emission layer, thereby maintaining good interface characteristics while still allowing the intermediate layer to improve emission efficiency.
Solution Approach 2:
The patent uses a solution process instead of vacuum deposition to form intermediate layers. This approach uses simple, inexpensive materials and processes that can be applied in a single step, avoiding the complexity and cost of vacuum equipment while achieving the desired function.
2Productivity
If both nozzle printing method and deposition method are used, then the manufacturing capability is improved, but the investment costs increase and large space is required
Solution Approach 1:
The patent combines the formation of multiple layers (emission layer, intermediate layers, electrodes) into a single solution process that can be performed in one manufacturing step. This merging of processes eliminates the need for separate vacuum deposition equipment and multiple manufacturing steps, reducing both investment costs and space requirements while maintaining manufacturing capability.
Solution Approach 2:
The solution process used in the patent is universal and can form multiple different layers (emission layer, hole injection layer, electron injection layer, electrodes) using the same basic methodology. This multi-functionality eliminates the need for specialized equipment for each layer type, reducing overall device complexity and investment costs.
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 improves the efficiency of OLED formation, reduces manufacturing costs, and allows for the production of large substrates in a simplified, in-line based system, eliminating the need for vacuum apparatuses and minimizing interface deterioration.
Implementation Method 1
a solution supply unit that communicates with the sub-pixel region with one color is formed in the sub-pixel region with one color, and emission layer raw materials for the plurality of colors are supplied to the sub-pixel region with one color and the other sub-pixel regions with other colors via the solution supply unit, whereby the EML is formed
Implementation Method 2
The EML may be formed by charging the at least one of the emission layer raw materials including a liquid emission layer raw material; and forming droplets by spraying the charged liquid emission layer raw material via the nozzle unit
Implementation Method 3
The charging the liquid emission layer raw material may include applying an electrical potential difference to the liquid emission layer raw material. A positive voltage may be applied to the nozzle unit, whereby the liquid emission layer raw material may be positively charged and then may be sprayed via the nozzle unit
Data Source
AI summary
In an organic light-emitting display device and a method of manufacturing the organic light-emitting display device, the method includes forming thin film transistors (TFTs) on a substrate; and forming organic light emitting diodes (OLEDs), each of the OLEDs including a first electrode having a portion exposed by a pixel defining layer (PDL) on the TFTs, an organic layer on the exposed portion of the first electrode and including an emission layer (EML) configured to emit light having a respective one of a plurality of colors, and a second electrode on the organic layer. The EML is formed in each of a sub-pixel region with one color and other sub-pixel regions with other colors that are formed by forming openings in the PDL. A solution supply unit for sub-pixel region that communicates with the sub-pixel region with one color is formed in the sub-pixel region with one color.