OLED Sub-Pixel Anode Segmentation for Defect Compensation
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Solution Overview
Problem
Organic light-emitting displays (OLEDs) face defects such as shorts and shadow phenomena due to contamination in the organic layer between anode and cathode electrodes, affecting pixel performance and leading to dark pixels.
Innovation Solution
The design incorporates a switch circuit system with PMOS or NMOS transistors that allows current to be selectively distributed between anode electrodes of adjacent sub-pixels, ensuring that light emission is maintained even if one or both anode electrodes in a sub-pixel are defective, thereby compensating for defects and preventing visual recognition of pixel failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single anode electrode is used in each sub-pixel, then the device structure is simple, but the reliability decreases due to contamination causing shorts or shadow phenomena
Solution Approach 1:
Each sub-pixel is divided into multiple anode electrodes (first anode electrode and second anode electrode) instead of using a single anode electrode. This segmentation allows independent control and compensation for each anode electrode, so that if one anode electrode becomes defective due to contamination or shorts, the other can still function to maintain pixel operation and prevent complete pixel failure.
Solution Approach 2:
The patent implements a switch circuit system with first and second switch circuits that can compensate for potential defects before they cause complete pixel failure. The switch circuits are designed in advance to detect and bypass defective anode electrodes, providing a cushioning effect that prevents contamination or shorts from leading to dark pixels or visible defects.
2Reliability
If multiple anode electrodes are used in each sub-pixel, then the reliability improves by compensating for defects, but the device complexity increases
Solution Approach 1:
The switch circuits are designed to perform multiple functions: they control current distribution to multiple anode electrodes, detect defective electrodes, and automatically compensate for defects. The first switch circuit controls the first anode electrode while the second switch circuit controls the second anode electrode, allowing a single switch circuit system to handle both normal operation and defect compensation scenarios.
Solution Approach 2:
The switch circuits dynamically adjust current distribution based on the operational status of each anode electrode. When one anode electrode is detected as defective, the switch circuit automatically redirects current to the functional anode electrode, providing dynamic adaptation to maintain pixel performance despite structural complexity.
3Illumination intensity
If current is supplied to multiple anode electrodes simultaneously, then the luminance is improved, but the risk of short circuits increases due to organic layer contamination
Solution Approach 1:
The switch circuits are designed to detect potential shorts or contamination issues before they cause complete pixel failure. By monitoring the electrical characteristics of each anode electrode through the switch circuits, the system can identify defective electrodes in advance and compensate by redirecting current to functional electrodes, thus cushioning against the harmful effects of contamination.
Solution Approach 2:
The switch circuits act as intermediary components between the power supply and the anode electrodes. They mediate current distribution by selectively connecting or disconnecting individual anode electrodes based on their operational status, preventing direct current flow through contaminated or shorted paths while still enabling luminance output through functional electrodes.
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 solution effectively compensates for defective sub-pixels, preventing black spots and luminance degradation, ensuring that images are not noticeably affected by such defects, thus enhancing the reliability and performance of OLED displays.
Implementation Method 1
Each of the first sub-pixels and each of the second sub-pixels in the first row include a light-emitting diode which includes multiple anode electrodes and a common cathode electrode
Implementation Method 2
An organic light-emitting display emits light using organic light-emitting diodes (OLEDs)
Data Source
AI summary
An organic light-emitting display includes first sub-pixels of a first color and second sub-pixels of a second color. Pairs of the first sub-pixels are consecutively arranged in different rows, and pairs of the second sub-pixels are consecutively arranged in different rows. The pairs of first sub-pixels and the pairs of second sub-pixels arranged alternately in a first column, and third sub-pixels are in a second column adjacent to the first column. When one sub-pixel is defective, a control circuit provides current another sub-pixel of the same color.