OLED Bank Perimeter Optimization for Current Leakage
Solution Overview
Problem
Current organic light emitting display (OLED) apparatuses experience current leakage between adjacent sub-pixels due to common layers, leading to color mixture and reduced brightness, especially at low gray scales, which affects display quality and increases power consumption.
Innovation Solution
Optimizing the shape of the bank between sub-pixels to increase the resistance of the common layer, with a perimeter of the bank's top surface on a cross-section being 7πμm or larger, thereby reducing current leakage without altering the light-emitting device design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a common layer is shared by adjacent sub pixels to simplify manufacturing, then manufacturing complexity is reduced, but current leakage occurs between sub pixels causing color mixture and reduced brightness
Solution Approach 1:
An insulating layer is introduced as an intermediary between adjacent sub-pixels on the bank structure. This insulating layer acts as a barrier that prevents current from leaking through the common layer to adjacent sub-pixels, while still allowing the common layer to be shared across multiple sub-pixels for manufacturing efficiency. The insulating layer is disposed on the bank and extends into the non-sub pixel area, creating an electrical barrier without disrupting the common layer's structural role.
2Reliability
If the perimeter of the bank's top surface is increased to reduce current leakage, then current leakage is reduced, but the device structure becomes more complex
Solution Approach 1:
The solution addresses current leakage not by complicating the horizontal geometry of the bank, but by utilizing the vertical dimension. The insulating layer is disposed on the top surface of the bank and extends downward into the non-sub pixel area, creating a three-dimensional barrier structure. This vertical approach to current isolation avoids increasing the bank's perimeter while still effectively blocking current leakage paths.
3Productivity
If the common layer is extended without disconnection to share across sub pixels, then manufacturing efficiency is improved, but current leakage increases causing unexpected sub pixel emission
Solution Approach 1:
The insulating layer is segmented to be disposed on different portions of the bank structure, specifically on the top surface and extending into the non-sub pixel area. This segmentation creates discrete isolation zones that prevent current leakage while maintaining the continuous structure of the common layer across sub-pixels. The common layer remains unbroken for manufacturing efficiency, while the insulating layer provides targeted current blocking where needed.
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
Minimizes current leakage between sub-pixels, improves display quality, allows for more flexible design of the light-emitting device, and prolongs the lifetime of the OLED apparatus without reducing the amount of inorganic material in the common layer.
Implementation Method 1
Optimizing the shape of the bank between sub-pixels to increase the resistance of the common layer
Data Source
AI summary
Provided is an organic light emitting display apparatus. The organic light emitting display apparatus includes: a first anode; a second anode which spaced apart from the first anode; a bank between the first anode and the second anode; and at least one common layer extending onto a top surface of the first anode, a top surface of the bank, and a top surface of the second anode, in which a perimeter of the top surface of the bank on the cross-section is 7πμm or larger. Accordingly, current leakage between adjacent sub pixels may be minimized.