Inkjet Head Flow Feedback for Precise OLED Ink Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing inkjet printing apparatuses struggle to precisely control the amount of ink discharged, leading to defects in the organic light emitting layer of OLED displays, especially as pixel sizes decrease.
Innovation Solution
The inkjet printing apparatus includes a stage, a head part with nozzles, an ink supply part with a uniquely designed opening that narrows in width from top to bottom, and a pressure applying part to control ink flow, along with an ink flow rate measuring system to adjust pressure based on measured flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size is decreased to achieve high resolution, then the display resolution is improved, but the ink discharge amount becomes harder to control precisely
Solution Approach 1:
The inkjet system is divided into multiple nozzles, each capable of independent ink discharge control. This segmentation allows precise control of ink amount for each pixel location, enabling high-resolution patterning even as pixel sizes decrease. The head part includes multiple nozzles that can be independently controlled to discharge appropriate ink amounts for each pixel.
Solution Approach 2:
An ink flow rate measuring part is provided to measure the flow rate of ink discharged through the opening. The controller uses this measured flow rate information to adjust and control the ink discharge amount, ensuring precise ink deposition even for decreased pixel sizes. This feedback mechanism compensates for variations in ink flow and maintains manufacturing precision.
2Ease of manufacture
If the ink discharge amount is not finely controlled, then the manufacturing process is simpler, but the organic light emitting layer quality deteriorates
Solution Approach 1:
An ink supply part with a specifically designed opening is provided as an intermediary component between the ink reservoir and the nozzle. This opening acts as a flow control element that regulates ink discharge. Additionally, a pressure applying part is introduced as another intermediary to apply controlled pressure to the ink, enabling fine adjustment of ink flow rate and discharge amount while maintaining manufacturing reliability.
3Productivity
If the opening width is increased to improve ink flow, then the ink supply efficiency is improved, but the ink discharge precision deteriorates
Solution Approach 1:
The system dynamically adjusts the pressure applied to the ink in the ink supply part based on measured flow rate. The controller modifies the pressure in real-time to maintain optimal ink discharge precision. This dynamic control allows the system to compensate for variations in opening dimensions and maintain precise ink discharge even when the opening width is increased for better ink supply efficiency.
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 design reduces defects in the organic light emitting layer by allowing precise control of ink discharge, ensuring accurate deposition on the substrate, thereby improving manufacturing quality.
Implementation Method 1
a pressure applying part disposed to contact an upper surface of the ink supply part, where the pressure applying part applies a pressure to the ink
Implementation Method 2
an ink flow rate measuring part connected to the ink supply part, where the ink flow rate measuring part measures a flow rate of the ink discharged through the opening
Implementation Method 3
the controller controls the pressure applying part to adjust the pressure applied to the opening based on the flow rate of the ink
Data Source
AI summary
An inkjet printing apparatus includes a stage, on which a substrate is disposed, a head part disposed above the stage, where the head part includes a nozzle which discharges ink, an ink supply part disposed between the stage and the head part, where an opening is defined through the ink supply part in a way such that the ink is received by the opening while overlapping the nozzle when viewed on a plane, and the ink supply part provides the ink onto the substrate through the opening, and an ink flow rate measuring part connected to the ink supply part, where ink flow rate measuring part measures a flow rate of the ink discharged through the opening.