Defect Inspection Circuit for Flexible Display Substrates
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Solution Overview
Problem
Display devices, such as LCDs and OLEDs, face challenges in accurately detecting defects like cracks in their substrates and stacked layers, which can lead to signal line disconnection and moisture penetration, especially in flexible displays that are prone to bending and warping, resulting in increased inspection complexity and potential errors.
Innovation Solution
A display device with a defect inspection circuit that includes sensing wires in the peripheral area connected to a resistance detection circuit, allowing for comparison of resistance values over time to determine the presence and progression of defects, thereby enhancing detection accuracy and reducing erroneous results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistance values are compared between multiple inspection operations, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The inspection circuit is segmented into distinct functional modules: sensing wires for resistance measurement, memory for storing inspection results, and comparator circuits for result analysis. This modular segmentation allows each component to perform its specific function efficiently while maintaining overall system accuracy without excessive complexity.
Solution Approach 2:
The memory component stores resistance values from previous inspection operations in advance, enabling subsequent comparisons with current inspection results. This preliminary storage action allows the comparator circuit to detect changes and defects by comparing historical data with current measurements, improving detection accuracy without requiring complex real-time analysis systems.
2Reliability
If sensing wires are added to the peripheral area, then defect detection capability is improved, but manufacturing complexity increases
Solution Approach 1:
The sensing wires in the peripheral area serve multiple functions: they detect cracks and defects in the substrate, measure resistance changes over time, and provide spatial distribution information for comprehensive defect analysis. This multi-functionality improves defect detection capability without requiring separate dedicated components for each function, thereby managing manufacturing complexity.
Solution Approach 2:
Multiple sensing wires are distributed across the peripheral area, creating redundant detection paths. Each sensing wire copies the detection function, and their collective resistance measurements provide comprehensive coverage. This copying approach enhances detection reliability while using simple, repeatable wire structures that are easy to manufacture.
3Measurement precision
If multiple inspection operations are performed at different times, then defect progression detection is improved, but inspection time increases
Solution Approach 1:
The inspection system performs resistance measurements at periodic intervals using the stored values in memory. By comparing resistance values from different time points, the system detects defect progression such as crack growth. This periodic measurement approach enables temporal analysis of defect development without requiring continuous monitoring, balancing detection precision with inspection time efficiency.
4Reliability
If sensing wires are positioned in the peripheral area, then coverage of bending regions is improved, but area occupied increases
Solution Approach 1:
Sensing wires are strategically positioned in the peripheral area where bending and warping occur most frequently in flexible displays. This localized placement concentrates detection resources in the regions most susceptible to defects, improving coverage of critical bending zones without requiring sensing wires across the entire display area, thus managing the occupied space efficiently.
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 improves the accuracy of defect inspection in display devices by comparing resistance values between sensing wires, allowing for precise detection of cracks and other defects, even in flexible displays, and reduces errors caused by process dispersion and wire width deviations.
Implementation Method 1
a resistance detection circuit that detects a resistance of the at least one sensing wire based on an output signal corresponding to the at least one sensing wire
Data Source
AI summary
A display device includes a defect inspection circuit, and a display panel having a display area and a peripheral area positioned outside the display area. The display panel includes a sensing wire positioned in the peripheral area and connected to the defect inspection circuit. The defect inspection circuit includes a resistance detection circuit that detects a resistance of the sensing wire based on an output signal corresponding to the sensing wire, a memory that stores first resistance information related to the resistance of the sensing wire detected in a first inspection operation, and a comparator circuit including a first comparator that compares the first resistance information with second resistance information. The second resistance information is related to the resistance of the sensing wire detected in a second inspection operation that is performed at a different time than the first inspection operation.