OLED Scan Line Short-Circuit Detection via Test Pad Waveform Analysis
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Solution Overview
Problem
The large width of power voltage supply lines in OLED display apparatuses increases the likelihood of short-circuit failures due to increased wire overlap with other layers, making it difficult to detect and repair such failures effectively.
Innovation Solution
The OLED display apparatus includes a configuration with scan wires branching into scan lines, data lines, a first power supply line, and second power supply lines that do not overlap with electrodes, along with test pads connected to scan lines to detect waveform anomalies and identify defective scan lines by comparing detected waveforms with previously determined defective waveforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power voltage supply line is made wider to supply sufficient current, then the current supply capability is improved, but the area where the wire overlaps other wires increases, leading to higher short-circuit failure risk
Solution Approach 1:
The power voltage supply line is divided into multiple separate power supply lines (ELVDD1, ELVDD2, etc.) that are distributed across different regions. Each scan wire has its own dedicated power supply line, preventing the need for a single wide power line that would create extensive overlap areas with other wires, thus reducing short-circuit risk while maintaining sufficient current supply capability.
2Reliability
If a short-circuit failure detection method is implemented, then the reliability is improved, but the device complexity increases due to additional test pads and detection circuits
Solution Approach 1:
The system uses its own existing scan lines and test pads to perform self-diagnosis for short-circuit detection. The scan lines are sequentially connected to test pads during a test mode, allowing the display apparatus to detect short-circuits in power supply lines using its own internal structures without requiring external detection equipment or additional complex detection circuits.
3Adaptability or versatility
If the scan lines are made to branch from scan wires to connect to sub pixels, then the connectivity to all sub pixels is improved, but the number of wire overlaps and potential short-circuit points increases
Solution Approach 1:
Different regions of the display apparatus are provided with dedicated power supply lines tailored to their specific requirements. Each scan wire region has its own power supply line with appropriate width and routing, optimizing current supply to connected sub pixels while minimizing overlap with other wires in that specific region, thus reducing short-circuit risk.
Data Source
AI summary
A display apparatus is disclosed. The apparatus includes a plurality of unit pixels each comprising a plurality of sub pixels, a plurality of scan wires, and a plurality of scan lines branching off from each of the scan wires and extending in a first direction. The number of scan lines from each scan wire equals the number of sub pixels for each pixel, and each scan line connects one of the scan wires with one of the sub pixels of each of a plurality of unit pixels. The apparatus also includes a plurality of data lines extending in a second direction orthogonal to the first direction and which are connected to the plurality of sub pixels. The apparatus also includes a first power supply line extending in the second direction and connected to the sub pixels, and a plurality of test pads, each connected to the scan lines of one of the scan wires.