Test Circuit Impedance Compensation for OLED Substrate Utilization
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Solution Overview
Problem
In the production of small-sized OLED products, group testing requires significant equipment and manpower, and the voltage drop along signal lines due to different impedances leads to reliability risks and luminance uniformity issues during aging and electrical tests, necessitating increased line widths that reduce substrate utilization.
Innovation Solution
A test circuit with independent output channels and a signal generating device that compensates test signals based on signal line impedance, allowing for accurate testing without increasing line width, ensuring each sub-board receives a consistent test signal by calculating compensation values based on line length and cross-sectional area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the line width of signal lines is increased to reduce voltage drop, then voltage stability is improved, but substrate utilization rate deteriorates
Solution Approach 1:
The patent changes the electrical parameters (voltage, current) of the signal lines dynamically to compensate for voltage drops caused by different line lengths and impedances. By adjusting the output signal parameters based on pre-calculated compensation values, the system maintains stable voltage at test points without requiring increased line width, thus preserving substrate utilization rate.
2Measurement precision
If independent testing of each product is performed, then test accuracy is improved, but equipment and manpower requirements increase
Solution Approach 1:
The patent segments the substrate into multiple independently testable regions with separate signal line groups. Each region has its own signal lines connected to different output terminals, allowing simultaneous independent testing of multiple products. This segmentation enables parallel testing that maintains accuracy while reducing overall equipment and manpower requirements.
Solution Approach 2:
The test circuit design allows a single testing system to handle multiple products simultaneously through multiple output channels. The signal generating device can provide compensated signals to multiple regions at once, making the testing equipment multi-functional and capable of testing several products in parallel, thereby reducing overall equipment requirements.
3Adaptability or versatility
If signal lines with different lengths are used for different sub-boards, then individual test requirements are met, but voltage drop variation increases
Solution Approach 1:
The patent implements a feedback mechanism where the signal generating device receives feedback information about line length and impedance characteristics, then automatically adjusts output signal parameters to compensate for voltage drops. This closed-loop control ensures voltage consistency across different sub-boards with varying line lengths while maintaining the flexibility to accommodate different test configurations.
Data Source
AI summary
The present disclosure belongs to the field of display technology, and particularly relates to a test circuit, a display substrate, a test method of a display substrate and a display apparatus. The test circuit includes a signal generating device and a plurality of output channels that are mutually independent. Each output channel includes a signal line configured to transmit a test signal. The signal generating device is coupled to the plurality of output channels, and is configured to provide, to each of at least one of the plurality of output channels, the test signal corresponding to an impedance of the signal line in the output channel, and provide the test signal to the signal line in the output channel.