AMOLED Pixel Circuit Testing Apparatus Using De-multiplexers
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Solution Overview
Problem
The existing technologies for fabricating Active Matrix Organic Electroluminescent Diode (AMOLED) panels face reduced yield due to defects in the pixel circuit before the organic electroluminescent material is evaporated, leading to wastage of expensive materials.
Innovation Solution
An apparatus and method for testing the pixel circuit on an organic electroluminescent display panel using a detecting control circuit, gate de-multiplexer, and source de-multiplexer to apply test signals and record output voltages, determining whether the pixel circuit functions properly before the organic electroluminescent material is formed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pixel circuit testing is performed before organic electroluminescent material evaporation, then manufacturing yield is improved and material wastage is reduced, but device complexity and testing time increase
Solution Approach 1:
The testing apparatus is divided into separate functional modules: detecting control circuit for signal generation and coordination, gate de-multiplexer for scan line signal distribution, source de-multiplexer for data line signal distribution, and level translation circuit for voltage level adaptation. This modular segmentation allows each component to perform its specific function efficiently while reducing overall system complexity.
Solution Approach 2:
The pixel circuit testing is performed before the organic electroluminescent material is evaporated onto the substrate. By conducting the defect detection in advance, the system identifies faulty pixel circuits early in the manufacturing process, preventing wastage of expensive organic materials on defective circuits and improving overall manufacturing yield.
2Productivity
If point-by-point pixel circuit testing is performed, then manufacturing yield is improved, but testing time and productivity are reduced
Solution Approach 1:
The testing apparatus continuously applies test signals to pixel circuits through the scan lines and data lines without interruption. The detecting control circuit generates continuous gate test signals and source test signals, allowing the testing process to proceed without stopping, thereby reducing overall testing time while maintaining comprehensive defect detection coverage.
Solution Approach 2:
The testing system uses periodic clock signals to control the sequential activation of scan lines and data lines. The detecting control circuit generates clock signals that rhythmically drive the testing process through the pixel array, enabling systematic and efficient point-by-point testing while maintaining continuous operation.
3Loss of substance
If comprehensive pixel circuit testing is performed before material evaporation, then material wastage is reduced, but manufacturing cost increases due to additional testing equipment
Solution Approach 1:
The testing apparatus utilizes the existing scan lines and data lines of the AMOLED substrate for testing purposes, rather than requiring completely separate dedicated test electrodes. The same gate and source circuits that will drive the display during normal operation are repurposed for testing, making the testing system multi-functional and reducing the need for additional expensive equipment.
Solution Approach 2:
The detecting control circuit acts as an intermediary that coordinates between the test signal generation and the pixel circuit under test. It generates appropriate gate test signals and source test signals, controls the timing and sequencing of tests, and processes the output signals to determine pixel circuit functionality, thereby simplifying the overall testing architecture.
Data Source
AI summary
An apparatus for testing an organic electroluminescent display panel having a plurality of data and scan lines comprises a detecting control circuit, a gate de-multiplexer and a source de-multiplexer. The detecting control circuit generates a gate test signal and a source test signal respectively to the gate de-multiplexer and the source de-multiplexer according to the position coordinate of a testing pixel in the organic electroluminescent display panel. The gate de-multiplexer and the source de-multiplexer send a gate testing voltage and a source testing voltage to one of the scan lines and one of the data lines respectively according to the gate and source test signals. In addition, the detecting control circuit further records an output voltage of the testing pixel.