OLED Mother Substrate Test Circuit for Signal Integrity
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Solution Overview
Problem
High-resolution organic light emitting displays face issues with voltage drop and signal delay when using pulse-shaped alternating current signals along long sheet wiring lines during sheet unit testing of mother substrates, affecting the effectiveness of the sheet unit test and aging process.
Innovation Solution
The implementation of a pixel arrangement structure where first and second sub-pixels are alternately arranged in the same columns, with separated data lines, and the use of a test circuit unit with transistors to supply test signals in direct current form, allowing for effective sheet unit testing by reducing distortion caused by voltage drop and signal delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulse-shaped alternating current signals are supplied along long sheet wiring lines for sheet unit testing, then the mother substrate can be tested, but voltage drop and signal delay occur causing waveform distortion
Solution Approach 1:
The patent segments the data lines into separate first data lines for first sub-pixels and second data lines for second sub-pixels. This segmentation allows independent routing and testing of different pixel types, reducing signal interference and distortion on long wiring lines while maintaining testing capability across the entire mother substrate.
Solution Approach 2:
The patent introduces a test circuit unit as an intermediary component that includes transistors coupled to the data lines. This test circuit unit mediates between the signal source and the pixels, allowing for signal conditioning, level shifting, and distortion compensation that ensures reliable signal integrity across long sheet wiring lines during sheet unit testing.
2Manufacturing precision
If first and second sub-pixels share the same columns to achieve high resolution, then display resolution is improved, but data lines for different sub-pixels must be separated increasing wiring complexity
Solution Approach 1:
The patent segments data lines by sub-pixel type, creating dedicated first data lines for first sub-pixels and second data lines for second sub-pixels. This segmentation strategy maintains high display resolution through alternating column arrangements while managing wiring complexity through systematic separation and routing of data lines for different pixel types.
Solution Approach 2:
The patent resolves wiring complexity by transitioning from a two-dimensional planar routing challenge to a three-dimensional solution using multiple wiring layers. Data lines for different sub-pixel types are routed on different layers, allowing high-resolution pixel arrangements without excessive planar wiring complexity.
3Adaptability or versatility
If sheet unit testing is performed on mother substrates with multiple high resolution panels, then testing capability is improved, but voltage drop and signal delay affect test accuracy
Solution Approach 1:
The test circuit unit acts as an intermediary that compensates for voltage drop and signal delay effects during sheet unit testing. The transistors in the test circuit unit can be controlled to provide signal regeneration and level restoration, ensuring that test measurements remain accurate even across long sheet wiring lines connecting multiple high-resolution panels on the mother substrate.
Solution Approach 2:
The patent employs parameter changes in the test circuit unit, specifically using controllable transistors that can adjust signal characteristics dynamically. By changing transistor operating states and signal parameters, the system compensates for voltage drop and signal delay, maintaining test accuracy across varying sheet substrate configurations and wiring lengths.
Data Source
AI summary
An organic light emitting display includes a display unit that includes scan lines and data lines. First sub-pixels, second sub-pixels, and third sub-pixels that emit light corresponding to different colors are repeatedly arranged in a uniform pattern. The organic light emitting display also includes a scan driver for supplying scan signals to the scan lines; a data driver coupled to one end of each of the data lines for supplying data signals to the data lines; a switch unit coupled between the one end of each of the data lines and the data driver to transmit the data signals supplied from output lines of the data driver to the data lines; and a test circuit unit including transistors coupled to other ends of the data lines. The first sub-pixels and the second sub-pixels are alternately arranged in same columns and the third sub-pixels are arranged in columns adjacent to the same columns.