Test Circuit for AMOLED Pixel Current Characteristic Diagnosis
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Solution Overview
Problem
In active-matrix organic light-emitting diode (AMOLED) technologies, diagnosing issues with EL devices is challenging due to the need for inline random inspection and high development costs associated with fabricating individual masks for debugging, which complicates identifying problem locations and causes within the array and EL substrates.
Innovation Solution
A test circuit with field-effect thin film transistors is integrated at the output terminal of a scan driving circuit, allowing for the testing of pixel unit current output characteristics without driving the scan driving circuit, using an enable signal line, scanning signal ON line, and switch transistors to determine the location of negative effects on light emission, eliminating the need for individual masks during EL recipe debugging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual masks are fabricated to shield the array substrate effect during EL recipe debugging, then EL device testing can be performed, but product development costs increase significantly
Solution Approach 1:
The patent extracts the testing function from the complete display module by introducing a test circuit that can independently activate pixel units without requiring the scan driving circuit. This allows EL device testing to be performed without fabricating individual masks to shield the array substrate, thereby reducing development costs while maintaining testing capability
Solution Approach 2:
The patent introduces a test circuit as an intermediary component between the pixel unit and the external testing equipment. This test circuit includes switch transistors that can be independently controlled to activate pixel units for EL current output characteristic testing, eliminating the need for complex mask fabrication processes
2Reliability
If inline random inspection is used to monitor device characteristics, then EL device problems can be detected, but problem location and cause analysis becomes difficult
Solution Approach 1:
The patent segments the pixel unit activation control by introducing switch transistors in the test circuit that can individually or selectively activate specific pixel units. This segmentation capability allows precise localization of problems by testing individual pixel units or groups, making it easier to identify the specific location and cause of EL device failures
Solution Approach 2:
The patent establishes a feedback mechanism where the EL current output characteristics are measured and can be used to determine the location of negative effects on light emission. The test circuit provides controlled activation and measurement capability that feeds back information about pixel unit performance, enabling systematic problem location and cause analysis
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
This solution enables efficient identification of problem locations within EL light-emitting devices, reducing product development costs by allowing for direct detection of current output characteristics without affecting the drive circuit, thereby pinpointing issues within the EL device or array substrate.
Implementation Method 1
a plurality of switch transistors, which are field-effect thin film transistors. Each of the switch transistors includes a first terminal, a second terminal, and a third terminal
Data Source
AI summary
The present disclosure discloses a test circuit, an array substrate, and a light-emitting display apparatus. The test circuit is arranged at an output terminal of a scan driving circuit and is configured to test a current output characteristic of a pixel unit when the scan driving circuit does not provide a drive signal for the pixel unit. Test circuit includes an enable signal line, a scanning signal ON line, and a plurality of switch transistors. Each of the switch transistors includes a first terminal, a second terminal, and a third terminal, wherein the first terminal of each of the switch transistors connects the enable signal line, the second terminal connects the scanning signal ON line, and the third terminal connects the pixel unit.