Flexible Display Test Layout for Crack Detection in Data Lines
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Solution Overview
Problem
Flexible displays are prone to cracks during manufacturing and bending, which can lead to inaccurate or non-functional pixel emission due to disconnection or increased resistance in data and scan lines, often undetected until after release.
Innovation Solution
Incorporating a test pad system with first and second test transistors, outlines, and resistances in non-display areas to detect cracks by supplying test and initialization signals, allowing for pre-release inspection and identification of defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flexible displays are bent during use, then flexibility and adaptability are improved, but cracks form in data and scan lines causing disconnection or increased resistance
Solution Approach 1:
The patent incorporates test pads, test transistors, and test outlines in the non-display area before the display module is assembled. These test structures allow crack detection to be performed in advance during the manufacturing process, enabling defective displays to be identified and removed before reaching customers. This preliminary detection action prevents the reliability issue from affecting end users.
2Difficulty of detecting and measuring
If test structures are added to detect cracks, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the test structures (test pads, test transistors, test outlines) to be located exclusively in the non-display area of the array substrate. This separation allows the test functions to be implemented without occupying display pixels or interfering with the visual display area. The test structures are taken out from the display functional area and placed in the peripheral non-display area, reducing the impact on device complexity while maintaining detection capability.
Solution Approach 2:
The test outlines are designed to traverse paths adjacent to the display area and connect to data lines that couple to specific colored pixels (e.g., green pixels). This multi-functional design allows the same test structure to detect cracks in multiple locations and associate them with specific data lines and pixel groups, enabling comprehensive crack detection using a unified test approach rather than requiring separate test structures for each location.
Data Source
AI summary
A display device includes a display area, a test pad, a plurality of first test transistors, and at least one outline. The display area includes pixels coupled to data lines and scan lines. The test pad receives a test signal. The first test transistors are coupled between the data lines of the display area and the test pad. The at least one outline is coupled between one of the first test transistors and the test pad. The at least one outline is located in a non-display area outside the display area.