Crack Sensing Line Over Encapsulation Layer in Flexible Displays
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Solution Overview
Problem
Existing flexible display devices face challenges in detecting cracks during manufacturing, which can lead to moisture permeation and degradation, particularly at the edges of thin film layers covering both display and non-display areas, resulting in device failure.
Innovation Solution
A display device design incorporating a substrate with a display area and a non-display area, featuring a plurality of signal lines, including gate lines and data lines, and crack sensing lines that overlap the encapsulation layer, allowing for crack detection by varying signal voltages applied during specific periods to identify disconnections or resistance changes indicative of cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If crack detection is performed using existing methods (leakage current measurement or separate detection lines), then crack detection capability is provided, but device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The data line is designed to serve dual purposes: transmitting data signals during normal operation and functioning as a crack detection line during inspection. This multi-functionality eliminates the need for separate detection lines, reducing device complexity while maintaining crack detection capability
Solution Approach 2:
The invention merges the data line and crack detection line into a single structure. By combining these functions into one line, the overall device complexity is reduced while preserving both data transmission and crack detection capabilities
2Measurement precision
If crack detection lines are added to the display device, then crack detection capability is improved, but ease of manufacture deteriorates due to additional wiring and bonding requirements
Solution Approach 1:
The data line performs both data transmission and crack detection functions, eliminating the need for separate detection wiring that would complicate the manufacturing process, particularly the bonding of FPC substrates
Solution Approach 2:
The crack detection function is extracted and integrated into the existing data line structure rather than adding separate detection infrastructure, simplifying the manufacturing process
3Area of stationary object
If the crack sensing line is formed on the encapsulation layer, then detection coverage is improved, but device complexity increases due to additional layer structure
Solution Approach 1:
The encapsulation layer serves dual purposes: protecting the display device and providing a substrate for the crack sensing line. This multi-functionality allows detection coverage over the encapsulated area without adding separate structural layers
Solution Approach 2:
The crack sensing line is merged with the encapsulation layer structure, allowing the sensing function to be integrated into the existing protective layer rather than requiring additional separate layers
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 effective detection of cracks in thin film layers, preventing deterioration and ensuring the reliability of flexible display devices by visualizing strong or weak bright lines corresponding to crack locations, thereby facilitating early damage identification and prevention.
Implementation Method 1
a first crack sensing line connected to a first one of the data lines... allowing for crack detection by varying signal voltages applied during specific periods to identify disconnections or resistance changes indicative of cracks
Data Source
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AI summary
A display device is disclosed. In one aspect, the device includes a substrate (SUB) including a display area (DA) and a non-display area (NDA) surrounding the display area (DA) and a plurality of pixels (RP) formed in the display area (DA). The device also includes a plurality of signal lines formed over the substrate (SUB) and electrically connected to the pixels (RP) and an encapsulation layer (EN) formed over the substrate (SUB) for protecting the pixels (RP), wherein the signal lines include a plurality of gate lines (S1, S2, .., Sn) and a plurality of data lines (D1a, D1b, .., Dma) formed over the substrate (SUB) and a first crack sensing line (CD1, CD2) electrically connected to a first one of the data lines (D1a, Dma) and overlapping the encapsulation layer (EN) in the depth dimension of the display device.