Organic EL Display Nozzle Grouping for Uniform Drop Volume
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Solution Overview
Problem
The existing methods for manufacturing organic EL display panels require complex control to ensure uniform drop volume from nozzles, which becomes impractical as the size of the panels increases, leading to variations in luminance between pixels.
Innovation Solution
A method involving the allocation of nozzles into groups and determining the ejection number for each nozzle based on detected volume variations, allowing for uniform drop volume distribution across apertures with simpler control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the waveform of driving voltage is adjusted for each nozzle to ensure uniform drop volume, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent changes the parameter being adjusted from driving voltage waveform to number of drops ejected. Instead of modifying the characteristics of each drop through voltage adjustment, the invention controls the total volume by varying the count of drops from each nozzle, which simplifies the control mechanism while achieving uniform distribution
Solution Approach 2:
The patent uses detection results from a reference nozzle to determine the ejection characteristics of other nozzles. By copying the detection approach and applying it systematically across multiple nozzles, the invention establishes a standardized control method that reduces complexity while maintaining precision
2Productivity
If the number of nozzles is increased to cover larger panel areas, then productivity is improved, but manufacturing precision deteriorates
Solution Approach 1:
The patent divides the large number of nozzles into multiple groups, with each group assigned to specific regions of the panel. This segmentation allows for localized control and detection, ensuring that each nozzle group maintains uniform drop volume characteristics even as the total number of nozzles increases to cover larger areas
Solution Approach 2:
The patent performs detection of drop volume characteristics for each nozzle before the actual manufacturing process. By preliminarily identifying and recording the ejection characteristics of all nozzles, the system can compensate for variations and ensure uniform distribution across the entire panel, regardless of the number of nozzles used
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 drop volume distribution across apertures, reducing luminance variations between pixels and simplifying control processes, even as the number of nozzles increases with larger panel sizes.
Implementation Method 1
A plurality of nozzles provided in the inkjet head eject drops of ink into each aperture
Implementation Method 2
an organic light-emitting layer that relies on the phenomenon of electroluminescence due to recombination of carriers
Data Source
AI summary
The volume per drop of the drops ejected by each nozzle is detected. It is then determined whether a volume of drops equal to or greater than a target value can be ejected by causing one or more first nozzles to eject drops, the detected volume per drop of the first nozzles falling within a first range of a preset value. When the determination is affirmative, the first nozzles are selected for ejection of drops. When the determination is negative, the first nozzles and one or more second nozzles are selected for ejection of drops. The detected volume per drop of the second nozzles falls within a second range of the present value, where the second range is greater than the first range.