LCD Panel ESD Protection via Segmented Short-Ring Circuits
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Solution Overview
Problem
Existing LCD panels face challenges in effectively eliminating electrostatic discharge during manufacturing, which can cause damage to thin-film transistor (TFT) devices and are also susceptible to electromagnetic interference (EMI) from current discharge protection methods.
Innovation Solution
The integration of inner and outer short-ring circuits around the LCD panel, where the outer rings are removable after edge grinding, allowing the inner rings to serve as both electrostatic discharge pathways and repair lines without occupying additional routing space, thereby minimizing EMI impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a short-ring circuit is used to disperse static electricity, then electrostatic discharge protection is improved, but electromagnetic interference (EMI) increases and interferes with LCD panel signals
Solution Approach 1:
The short-ring circuit is divided into two segments: inner short-rings adjacent to the display area and outer short-rings adjacent to the panel edge. This segmentation allows the inner short-rings to provide ESD protection while the outer short-rings can be removed after manufacturing to eliminate EMI sources, thus resolving the contradiction between protection effectiveness and interference reduction.
Solution Approach 2:
The outer short-rings are designed to be temporarily present during manufacturing to provide complete ESD protection, then removed via edge grinding after the manufacturing process is complete. This preliminary action approach allows the system to have full protection during the critical manufacturing phase when ESD risk is highest, while eliminating the EMI source for the final product.
2Reliability
If the resistance of the short-ring circuit is reduced to disperse static electricity more effectively, then electrostatic discharge protection is improved, but electromagnetic interference (EMI) generation increases
Solution Approach 1:
The circuit is segmented into inner and outer short-rings with different resistance characteristics. The inner short-rings have lower resistance to effectively disperse static electricity, while the outer short-rings can be removed to eliminate the EMI generation source, thus resolving the contradiction between effective static dispersion and EMI reduction.
3Reliability
If additional short-ring circuits are added for electrostatic discharge protection, then protection effectiveness is improved, but device complexity and routing layout increase
Solution Approach 1:
The inner short-rings are designed to serve dual functions: providing ESD protection during manufacturing and serving as laser repair lines after the outer short-rings are removed. This multi-functionality approach allows the same circuit element to provide both protection and repair capabilities, reducing overall device complexity while maintaining enhanced ESD protection.
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 provides enhanced electrostatic discharge protection and laser-repairing functionality without compromising display quality, improving manufacturing yield and reliability by effectively dispersing static electricity and reducing EMI interference.
Implementation Method 1
the static electricity generated by the manufacturing process accumulates in the LCD panel to cause high potential difference between the LCD panel and the TFT. When the accumulated static electricity is discharged, an instantaneous current with high voltage can affect the function of the TFT
Implementation Method 2
the remaining inner short-rings can be used as repairing lines for repairing the defects occurring on the display area
Data Source
AI summary
A liquid crystal display with electrostatic discharge protection includes an inner short-ring which surrounds the display region and an outer short-ring which surrounds the inner short-ring, wherein the inner short-ring and the outer short-ring are both located near the panel edge. The inner short-ring is connected with the display region indirectly, and the outer short-ring is electrically connected with the display region and the inner short-ring at the same time. The inner short-ring is electrically connected with the display region through the outer short-ring, and the inner short-ring can serve as a repair line after edge grinding the panel.