Display Panel Functional Layer Film Thickness Control
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Solution Overview
Problem
The existing wet process for manufacturing self-luminous display panels faces limitations in controlling film thickness of functional layers, particularly when using the same ink for different light emission colors, leading to inefficiencies and increased costs due to the need for multiple inks and complex process management.
Innovation Solution
A display panel design where a first functional layer with a specific film thickness is formed in one pixel region and a second functional layer with a smaller film thickness, using the same ink, is created by adjusting the area ratio of the functional layers within each pixel region, allowing for easier control of film thickness without ink overflow or uniformity issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the film thickness of functional layers is controlled by changing the amount of application of the same ink in the wet process, then the manufacturing process is simplified and cost is reduced, but the film thickness range is limited by ink viscosity and coating device constraints
Solution Approach 1:
The patent changes the concentration parameter of the ink to achieve different film thicknesses. By preparing inks with different concentrations (e.g., 10 wt%, 20 wt%, 30 wt%) of the same functional material, the coating process can produce functional layers with different thicknesses while using the same coating device and process conditions, thus expanding the controllable film thickness range without increasing process complexity
Solution Approach 2:
The patent segments the ink preparation process into multiple concentration variants. Instead of using a single ink formulation, the method divides the material application into several ink types with systematically different concentrations, allowing precise control over film thickness while maintaining uniformity within each pixel region
2Manufacturing precision
If different concentrations of ink are used to achieve different film thicknesses, then film thickness control is improved, but the ink must be managed as different kinds of ink increasing process management cost
Solution Approach 1:
The patent systematically varies the concentration parameter of the ink while keeping the base formulation constant. This approach allows different film thicknesses to be achieved through a controlled parameter change rather than completely different ink formulations, simplifying the management framework while maintaining precision in film thickness control
Solution Approach 2:
The patent makes a single base ink formulation serve multiple functions by adjusting its concentration. The same functional material can produce different film thicknesses when dissolved at different concentrations, allowing one ink type to replace multiple specialized inks and reducing overall management complexity
3Manufacturing precision
If the amount of ink application is increased to achieve greater film thickness, then the desired optical path length is achieved, but ink overflow from partition walls occurs
Solution Approach 1:
Instead of increasing the amount of application to achieve greater film thickness, the patent changes the concentration parameter of the ink. This allows the desired film thickness and optical path length to be achieved with the same application amount, preventing ink overflow while maintaining manufacturing precision
Solution Approach 2:
The patent uses ink concentration as an intermediary parameter to mediate between the desired film thickness and the application amount. By adjusting concentration rather than quantity, the system achieves the target optical path length without exceeding the partition wall containment capacity
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 enables efficient film thickness control for functional layers across different light emission colors using the same ink, simplifying manufacturing processes and reducing costs while maintaining high light extraction efficiency.
Implementation Method 1
a lower limit amount of ink per unit area is determined by the viscosity of the ink and constraints of a coating device, while an upper limit amount thereof is determined from a viewpoint of suppressing an overflow from partition walls
Implementation Method 2
a lower limit amount of ink per unit area is determined by the viscosity of the ink and constraints of a coating device
Implementation Method 3
Display devices using self-luminous elements such as organic electroluminescence (EL) elements utilizing an electroluminescence phenomenon of an organic material
Implementation Method 4
quantum-dot light emitting diodes (QLEDs) utilizing a quantum dot effect
Data Source
AI summary
Disclosed herein is a display panel in which a plurality of pixel regions are arranged in a matrix form, the display panel including a substrate, a plurality of pixel electrodes, a partition wall, a first functional layer, a first light emitting layer, a second functional layer, and a second light emitting layer. As viewed in plan, a ratio of an area of the first functional layer to an area of the pixel region in which the first functional layer is present being lower than a ratio of an area of the second functional layer to an area of the pixel region in which the second functional layer is present.