Organic Light-Emitting Display With Concave Convex Overcoat Layer
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Solution Overview
Problem
Existing organic light-emitting displays face challenges in reducing the non-emitting region area and improving space utilization for high-resolution displays with high pixels per inch, as the conventional bank structure limits the aperture ratio and requires complex alignment processes.
Innovation Solution
The proposed solution eliminates the conventional bank structure by using an overcoat layer with concave and convex portions to define pixels, incorporating auxiliary organic light-emitting diodes and transistors, and separate driving signals for enhanced space utilization and alignment, allowing the non-emitting region to function as a variable region for light emission or reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the conventional bank structure is used to define pixels, then the aperture ratio can be maximized, but the non-emitting region occupies excessive area and limits space utilization
Solution Approach 1:
The non-emitting region is transformed into a multi-functional auxiliary pixel that can perform both reflective and light-emitting functions. The auxiliary electrode in the non-emitting region can reflect external light when not driven, or emit light when driven as an auxiliary organic light-emitting diode, thereby utilizing the previously wasted area for additional display functions and improving overall space utilization
Solution Approach 2:
The non-emitting region is converted into a dynamic auxiliary pixel that can switch between different functional states. By applying different driving signals, the auxiliary electrode can transition between reflecting external light and emitting light through the auxiliary organic light-emitting diode, making the region adaptable to different display needs and improving space efficiency
2Manufacturing precision
If the bank structure is used for pixel definition, then pixel boundaries are clearly defined, but the alignment process becomes complex and manufacturing yield decreases
Solution Approach 1:
The patent removes the conventional bank structure entirely and replaces it with an overcoat layer having concave and convex portions. This extraction of the bank structure eliminates the complex alignment processes required for bank formation while maintaining pixel definition through the topography of the overcoat layer, thereby simplifying manufacturing and improving yield
Solution Approach 2:
Instead of using a planar bank structure, the patent introduces vertical dimensionality through concave and convex portions of the overcoat layer. The first electrode is positioned in the concave portion while the auxiliary electrode is on the convex portion, creating pixel definition through height differences rather than lateral boundaries, which simplifies the alignment process
3Area of stationary object
If additional reflecting members are added to utilize the non-emitting region, then space utilization improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The auxiliary electrode in the non-emitting region serves dual purposes: it acts as a reflective electrode when not driven to reflect external light, and as an anode for the auxiliary organic light-emitting diode when driven to emit light. This eliminates the need for separate reflecting members while improving space utilization and reducing device complexity
Solution Approach 2:
The auxiliary electrode provides its own reflective function without requiring additional reflecting members. The organic light-emitting materials in the auxiliary pixel serve both as emission layers for light generation and as functional components for the auxiliary diode operation, reducing the need for separate components and simplifying the overall structure
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 reduces manufacturing costs and defects, improves process yield, and enhances picture quality by effectively utilizing the non-emitting region for additional functions, such as light emission or reflection, without the need for additional reflecting members.
Implementation Method 1
The auxiliary electrode is a reflective electrode
Implementation Method 2
organic light-emitting displays are self-luminous displays that emit light through excitation of organic compounds
Implementation Method 3
functions as a reflective electrode to reflect an image of an object located in one direction when the auxiliary thin-film transistor is turned off
Data Source
AI summary
An organic light-emitting display comprises an overcoat layer disposed on a substrate, the overcoat layer having concave portion and convex portion disposed between neighboring concave portions, and an organic light-emitting diode and an auxiliary organic light-emitting diode disposed on the overcoat layer. A first electrode of the organic light-emitting diode is placed in the concave portion. An auxiliary electrode of the auxiliary organic light-emitting diode is placed on the convex portion.