Display Panel Test Circuit Design for High Accuracy and Compact Pads
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Solution Overview
Problem
Current visual test (VT) methods for display panels have low accuracy and are inadequate in effectively testing the quality of display panels, leading to potential defective products in the assembly process.
Innovation Solution
A display panel configuration that includes a test circuit, display control circuit, and selection circuit with specific switch and signal line connections, allowing for precise testing while minimizing the area occupied by test pads, thereby improving test accuracy and reducing the non-display region, which enhances the screen-to-body ratio and facilitates easier identification of abnormalities during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional VT test configuration is used, then the test can be performed, but the test accuracy is low and cannot effectively test quality of the display panel
Solution Approach 1:
The patent divides the testing function into separate dedicated test circuits and test switches, distinct from the display control circuits. This segmentation allows independent testing operations that do not interfere with normal display functions, enabling accurate detection of data line abnormalities without being affected by display control signals.
Solution Approach 2:
The patent introduces test switches as intermediary components between the test signal source and the data lines. These test switches act as controlled access points that allow test signals to be injected into specific data lines without affecting the normal display signal path, thereby enabling accurate testing while maintaining display functionality.
2Ease of operation
If test pads are provided to control display switch during VT test, then the display switch can be turned off, but the area of non-display region increases excessively
Solution Approach 1:
The patent designs test switches that share control lines with display control circuits, allowing the same control infrastructure to serve both display control and test functions. This multi-functionality eliminates the need for separate dedicated pads solely for test operations, reducing the non-display region area while maintaining full control capability during testing.
Solution Approach 2:
The patent merges the test control functionality with the existing display control circuitry by using shared control lines and integrated switch designs. This consolidation allows the display control lines to serve dual purposes during test modes, eliminating redundant control pads and reducing the overall non-display region area.
3Measurement precision
If test circuits are added to improve test accuracy, then test quality improves, but the device complexity increases
Solution Approach 1:
The patent uses test switches that are identical in structure and control mechanism to the display switches already present in the display panel. This homogeneity allows the test circuits to be manufactured using the same processes and materials as the display circuits, minimizing additional complexity while achieving accurate testing functionality.
Data Source
AI summary
A display panel is provided, including a test circuit, a display control switch and a selection circuit. In the test circuit, the test switch has a control terminal connected to the test control line, a first terminal connected to the test signal line, and a second terminal connected to the data line. In the display control circuit, the display switch has a control terminal connected to the display control line, a first terminal connected to the display signal line, and a second terminal connected to the data line. In the selection circuit, the selection switch has a control terminal connected to the selection control line, a first terminal connected to the selection signal terminal, and a second terminal connected to the display control line. The selection signal terminal provides a signal for turning off the display switch when the test switch and the selection switch are turned on.