OLED Common Electrode Test Pattern for Resistance Verification
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Solution Overview
Problem
Existing display apparatuses, particularly OLED displays, face challenges in accurately measuring the resistance of the common electrode, which affects operation and power consumption, and ensuring proper formation of contact holes and separation grooves to prevent electrical leakage.
Innovation Solution
Incorporating a test sample pattern on the display substrate, formed of the same material as the common electrode, with connection pads and pads outside the encapsulation layer, allowing resistance measurement and verification of laser drilling and separation groove formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test means is established to measure common electrode resistance, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The test structure is segmented into distinct functional components: test sample pattern (isolated common electrode region), connection pads (for electrical contact), and test pads (for measurement access). This segmentation allows each component to perform its specific function while maintaining overall measurement capability without excessive complexity
Solution Approach 2:
Connection pads and test pads serve as intermediary elements between the test sample pattern and the measurement instrument. These pads provide standardized interfaces for electrical contact, enabling resistance measurement without directly complicating the test sample structure itself
2Productivity
If laser drilling is used to form contact holes, then manufacturing efficiency is improved, but measurement of drilling quality becomes difficult
Solution Approach 1:
The test sample pattern is prepared in advance with predefined contact hole positions and dimensions that match the laser drilling parameters. This preliminary preparation allows the laser drilling process to be directly validated on the test structure, enabling quality verification of contact hole formation without requiring separate test structures
Solution Approach 2:
The test sample pattern replicates the actual device structure (common electrode, organic encapsulation layer, contact holes) at a reduced scale or in isolated regions. This copying approach allows laser drilling quality to be measured and verified on the test structure, ensuring the same quality in the actual device manufacturing
3Reliability
If separation grooves are formed to prevent electrical leakage, then device reliability is improved, but verification of groove formation becomes difficult
Solution Approach 1:
The separation groove structure is extracted and isolated in the test sample pattern, separate from the main device structure. This extraction allows the separation grooves to be specifically targeted for verification using test pads positioned on either side of the grooves, enabling direct measurement of their effectiveness in preventing electrical leakage without interference from other device components
Solution Approach 2:
Test pads are positioned on either side of the separation grooves in the test sample pattern, creating a feedback mechanism. By measuring electrical properties between these test pads, the formation quality and effectiveness of the separation grooves can be directly verified, providing feedback on whether the grooves are properly formed and functioning to prevent electrical leakage
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
Enables precise measurement of common electrode resistance and confirms correct laser drilling and separation groove formation, ensuring optimal electrical performance and preventing leakage.
Implementation Method 1
The first contact hole may be formed using laser drilling.
Data Source
AI summary
A display apparatus is disclosed that includes a display substrate, a test sample pattern, connection pads, test pads, and pad connection lines. The display substrate is partitioned into a display area and a non-display area surrounding the display area and includes a conductive wiring, a pixel electrode, and a common electrode disposed in the display area, and an organic encapsulation layer covering the conductive wiring, the pixel electrode, and the common electrode. The test sample pattern is disposed in the non-display area, formed of a same material on a same layer as the common electrode, and covered by the organic encapsulation layer. The connection pads contact the test sample pattern and are separate from each other. The test pads are disposed in a position outside the organic encapsulation layer in the non-display area. The pad connection lines connect the connection pads and the test pads.