OLED Short Circuit Preventing Layer for Leakage Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light emitting devices are prone to short defects due to pinholes, cracks, and structural imperfections, leading to reduced light emission and operational issues, even when manufactured in clean environments, as existing methods to mitigate these defects increase costs and do not completely eliminate the problem.
Innovation Solution
Incorporating a short circuit preventing layer with high resistance values on the substrate, which separates the first and auxiliary electrodes and controls leakage current, preventing current flow to defect regions and maintaining normal operation even with short circuits, while also acting as a barrier to moisture and oxygen when using a plastic substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the organic layer is increased to decrease short defects, then the number of short defects is reduced, but manufacturing costs increase and short defects are not completely removed
Solution Approach 1:
The device is segmented into multiple functional layers including a substrate, organic light-emitting layer, and transparent conductive layers. This segmentation allows the introduction of a charge blocking layer at specific interfaces to prevent short circuits without increasing the overall organic layer thickness, thereby maintaining manufacturing cost efficiency while improving reliability.
Solution Approach 2:
A charge blocking layer is introduced as an intermediary component between the organic light-emitting layer and the transparent conductive layer. This intermediary layer specifically blocks charge carrier leakage at defect regions (pinholes, cracks) without requiring increased organic layer thickness, thus resolving the contradiction between reliability improvement and manufacturing cost control.
2Reliability
If the thickness of the organic layer is increased to decrease short defects, then the number of short defects is reduced, but the organic light emitting device structure becomes more complex
Solution Approach 1:
The charge blocking function is extracted from the organic light-emitting layer itself and implemented as a separate, dedicated charge blocking layer. This extraction allows the organic layer to maintain its original optimized thickness for light emission while the charge blocking layer handles defect prevention, thus improving reliability without increasing organic layer thickness or overall device complexity.
Solution Approach 2:
The charge blocking layer serves multiple functions: it blocks charge carriers at defect regions to prevent short circuits, maintains the integrity of the organic light-emitting layer at its optimal thickness, and provides a barrier against moisture and oxygen penetration. This multi-functionality improves reliability without requiring increased organic layer thickness or complicating the device structure.
3Reliability
If manufacturing is carried out in a clean room to reduce short defects, then the number of defects is reduced, but it cannot be effective in removing short defects completely
Solution Approach 1:
The charge blocking layer is designed to preemptively block charge carrier leakage at potential defect sites (pinholes, cracks) before such defects can cause short circuits during device operation. This preliminary protective action ensures reliable operation even when manufacturing in clean room conditions, making the device less sensitive to manufacturing environment variations.
Solution Approach 2:
The charge blocking layer acts as a cushioning protective barrier that prevents the harmful effects of short defects from manifesting. By placing this layer between the organic light-emitting layer and transparent conductive layer, it cushions against charge carrier leakage through defects, ensuring stable device operation without requiring stricter manufacturing cleanliness controls.
4Reliability
If transparent conductive layers are formed directly on the substrate to improve conductivity, then electrical conductivity is improved, but short defects occur due to direct contact between electrodes
Solution Approach 1:
The charge blocking layer serves as an intermediary barrier between the organic light-emitting layer and the transparent conductive layer. It allows the transparent conductive layer to maintain its electrical conductivity function while preventing charge carrier leakage through defects in the organic layer, thus improving electrical conductivity without introducing short circuit defects.
Solution Approach 2:
The charge blocking layer provides localized charge carrier blocking at the interface between the organic light-emitting layer and transparent conductive layer. This local quality enhancement specifically addresses defect regions without affecting the overall electrical conductivity of the transparent conductive layer, thus resolving the contradiction between conductivity improvement and short circuit prevention.
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
The solution allows the organic light emitting device to maintain normal function and prevent excessive leakage current, even with short circuit defects, while ensuring stable operation and light extraction, and provides a cost-effective method to minimize defects without increasing manufacturing costs.
Implementation Method 1
Incorporating a short circuit preventing layer with high resistance values on the substrate, which separates the first and auxiliary electrodes and controls leakage current
Implementation Method 2
An organic light emission phenomenon refers to a phenomenon converting electrical energy to light energy using an organic material. When a proper organic material layer is placed between an anode and a cathode and a voltage is applied between the two electrodes, holes and electrons are injected to the organic material layer from the anode and the cathode, respectively. These injected holes and electrons meet to form excitons, and light emits when these excitons fall back to the ground state.
Implementation Method 3
When a plastic substrate is used in an organic light emitting device according to one embodiment of the present specification, the short circuit preventing layer can perform a role of a barrier film preventing moisture and oxygen permeation
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present specification relates to an organic light emitting device and a method for manufacturing the same.