Display Panel Test Pad Segmentation for Early Defect Detection
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Solution Overview
Problem
In the manufacturing of display devices, defects in signal lines and pads cannot be detected until the final module test process, leading to increased manufacturing time and reduced production yield, as only some pads can be tested during the visual inspection before the driving chip is mounted.
Innovation Solution
A display device with a visual inspection test process that includes additional test pads and switching elements connected to the display signal lines, allowing for the detection of defects in pads used for attaching the driving chip and flexible printed circuit film before the driving chip is mounted, enabling the testing of all pads during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional visual inspection test is performed before mounting the driving chip, then only some pads can be tested, but defective pads cannot be detected until the final module test process
Solution Approach 1:
The test pad configuration is segmented into multiple functional groups: first test pads connected to first switching elements for controlling signal lines, second test pads connected to second switching elements for direct pad testing, and third test pads for additional testing functions. This segmentation allows different portions of the circuit to be tested independently and simultaneously, enabling comprehensive defect detection before driving chip mounting.
Solution Approach 2:
The patent implements preliminary testing actions by configuring test pads and switching elements that enable inspection of signal lines and pads before the driving chip is mounted. The first switching elements can be controlled to connect test pads to signal lines in advance, allowing defects to be detected during the visual inspection test process rather than waiting for the final module test.
2Productivity
If comprehensive testing of all pads is performed during the visual inspection process, then manufacturing time is reduced and production yield increases, but additional test pads and switching elements are required
Solution Approach 1:
The switching elements serve multiple functions: they act as pixel switching elements during normal display operation and as test switching elements during the visual inspection test. The test pads are integrated into the existing pad structure, allowing the same physical infrastructure to serve both display functionality and testing functionality, thereby reducing the need for entirely separate test components.
Solution Approach 2:
The patent merges the test circuitry with the display circuitry by integrating test pads alongside display pads and using switching elements that function in both test and display modes. This merging allows comprehensive testing to be performed using the existing display panel structure, reducing the need for separate dedicated test components and minimizing additional complexity.
Data Source
AI summary
The present invention relates to a display device. The display device includes a display panel having gate lines and data lines, a driving chip mounted on the display panel, and a flexible printed circuit film (FPC) attached to the display panel. The display panel includes a plurality of first to third pads, a first switching element, a second switching element, a first test pad, and a second test pad. The plurality of first to third pads are sequentially disposed and electrically connected with each other. The first switching element is interposed between the first pad and the second pad. The second switching element is connected to the third pad. The first test pad is commonly connected to control terminals of the first and second switching elements. The second test pad is connected to an input terminal of the second switching element. According to the present invention, processing time and production yield can be increased by improving the detection performance in a visual inspection test process.