LCD Panel Test Transistors Eliminate Shorting Bar Corrosion
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Solution Overview
Problem
Conventional LCD manufacturing methods require shorting bars for testing, which can lead to reliability issues due to potential corrosion and contamination, and involve a complex process for their removal.
Innovation Solution
Incorporating test transistors on the LCD panel that can be selectively activated during testing and permanently turned off after the attachment of the driving integrated circuit, eliminating the need for shorting bars and simplifying the testing and manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If shorting bars are used for testing signal lines and transistors, then defect detection capability is improved, but device complexity and manufacturing steps increase
Solution Approach 1:
The patent extracts the testing function from the peripheral shorting bar structure and integrates it directly into the pixel array by using test transistors formed within the display region. This eliminates the need for separate shorting bars and their associated removal processes, reducing device complexity while maintaining defect detection capability.
Solution Approach 2:
The test transistors serve multiple functions: they act as both testing elements for defect detection and as functional elements of the pixel array when activated during normal operation. This multi-functionality eliminates the need for separate dedicated testing structures like shorting bars.
2Productivity
If shorting bars are removed after testing, then testing process is completed, but reliability deteriorates due to potential corrosion and contamination at cut surfaces
Solution Approach 1:
The patent removes the harmful element (shorting bars that require cutting and removal) by extracting the testing function into the pixel array itself. The test transistors are formed within the display region and can be selectively activated without requiring any cutting or removal processes, thereby eliminating the source of reliability issues.
Solution Approach 2:
Instead of using shorting bars that create harmful cut surfaces requiring removal, the patent converts the testing function into a beneficial integrated feature. The test transistors provide a clean, contamination-free testing mechanism that actually improves reliability by eliminating the need for destructive removal processes.
3Device complexity
If test transistors are permanently turned off after Driver IC attachment, then manufacturing complexity is reduced, but adaptability for future testing is limited
Solution Approach 1:
The test transistors are designed with dynamic control capability, allowing them to be selectively activated or deactivated based on operational needs. During manufacturing and testing phases, they can be activated for defect detection, and after Driver IC attachment, they can be permanently turned off to simplify the structure, or reactivated if future testing is needed.
Solution Approach 2:
The patent employs parameter changes in the control signals to the test transistors, allowing their operational state to be changed from active during testing to inactive during normal operation. This dynamic parameter control provides flexibility for different manufacturing stages and future testing requirements without permanent structural modifications.
Data Source
AI summary
A liquid crystal display (LCD) panel simplifying its testing and manufacturing. The LCD panel includes (formed on a substrate) gate lines, data lines, and pixels including pixel transistors. The LCD panel further includes a plurality test transistors (e.g., data test transistors for driving the odd and even data lines) formed in a package region of a driving IC (integrated circuit) configured to drive the data lines. The plurality of test transistors may be selectively activated (turned ON) during testing before the driving integrated circuit (Driver IC package) is attached (e.g., fixed) to the driving IC package region. The LCD panel may further include a plurality of gate test transistors configured to drive the odd and even gate lines.