Flexible Display Crack Sensor Circuit for Accurate Defect Detection
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Solution Overview
Problem
Display devices, particularly flexible ones, are prone to cracks during manufacturing and use, which can lead to signal line disconnection, increased resistance, and moisture penetration, reducing reliability and causing malfunction.
Innovation Solution
A display device with a crack sensor and shorting elements connected to input pads and data lines, along with a crack sensing circuit, to detect cracks and protect internal components from static electricity, ensuring accurate defect detection and prevention of erroneous defect testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible display device is bent and warped during manufacture or use, then the device becomes more adaptable to different form factors, but fine cracks in the substrate or laminated layers grow into larger cracks, reducing reliability
Solution Approach 1:
The patent applies preliminary action by introducing a crack sensor that proactively detects cracks before they grow into larger defects. The sensor is pre-installed in the bending area to monitor for early-stage cracks during manufacturing and use, allowing preventive measures to be taken before reliability is compromised.
Solution Approach 2:
The crack sensor acts as an intermediary between the substrate and the monitoring system. It is positioned in the bending area to detect cracks without interfering with the flexibility of the display device, mediating between the need for flexibility and the risk of crack propagation.
2Measurement precision
If a crack sensor is added to detect cracks, then defect detection capability is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by positioning the crack sensor specifically in the bending area where cracks are most likely to occur, rather than distributing sensors throughout the entire display device. This localized approach improves crack detection accuracy while minimizing the increase in device complexity.
Solution Approach 2:
The crack sensor uses a simplified sensing mechanism that copies the essential function of comprehensive crack detection without requiring complex sensor arrays. The sensor design leverages existing sensing technologies adapted for this specific application, reducing overall system complexity.
3Reliability
If shorting elements are connected to protect from static electricity, then component protection is improved, but signal line connectivity may be affected
Solution Approach 1:
The shorting element is designed to be dynamic, switching between connected and disconnected states based on the presence of static electricity. During normal operation, it remains disconnected to maintain signal line connectivity. When static electricity is detected, it automatically connects to provide protection, thus resolving the contradiction between protection and connectivity.
Solution Approach 2:
The shorting function is extracted as a separate, controllable element rather than being permanently integrated into the signal line. This allows the shorting element to be selectively activated only when needed for static electricity protection, preventing interference with normal signal transmission while maintaining protection capability.
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 effectively detects cracks and protects against static electricity, enhancing the reliability of display devices by preventing signal line disconnection and moisture penetration, while ensuring accurate defect testing and minimizing erroneous defect detection.
Implementation Method 1
The crack sensor may include a line extending along a periphery of the display area... capable of detecting defects such as cracks
Implementation Method 2
shorting elements connected to input pads and data lines... protecting internal components from static electricity
Data Source
AI summary
A display device includes a substrate includes a display area having a plurality of pixels, a pad area including a plurality of input pads, and a circuit area positioned between the pad area and the display area; a crack sensor having a first end and a second end, the first end being connected to a first input pad of the plurality of input pads; a first shorting element extending through the pad area, the first shorting element being connected to the second end and extending to an edge of the substrate; a plurality of data lines connected to the plurality of pixels; and a crack sensing circuit including a first switching element having an input terminal connected to the first end and an output terminal connected to a first data line of the plurality of data lines, and a second switching element having an input terminal connected to the second end and an output terminal connected to a second data line of the plurality of data lines.