LCD ESD Tolerance via Segmented Short-Circuit Paths
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Solution Overview
Problem
Liquid crystal display (LCD) devices have low electrostatic discharge (ESD) tolerance, which can damage thin film transistors during ESD testing, leading to potential device failure.
Innovation Solution
The LCD device incorporates a common line and a plurality of short-circuit portions with varying contact surface sizes and numbers of contact holes, strategically positioned to enhance ESD discharge, including larger contact surfaces at the corners of the substrate to efficiently manage and discharge ESD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LCD structure is used, then manufacturing is simple, but ESD tolerance is low causing TFT damage
Solution Approach 1:
The invention divides the discharge path into multiple segments by creating several short-circuit portions distributed across the substrate. Each short-circuit portion includes contact holes penetrating through insulating layers to establish discharge paths from the common line to the common electrode. This segmentation allows ESD to be discharged through multiple distributed paths rather than a single path, improving ESD tolerance while maintaining manageable structural complexity
Solution Approach 2:
The invention introduces short-circuit portions as intermediary structures between the common line and common electrode. These short-circuit portions serve as controlled discharge paths that mediate the ESD energy dissipation process, protecting the TFT from direct ESD damage. The intermediary structures include conductive layers and contact holes that facilitate safe energy dissipation
2Reliability
If uniform short-circuit portions are used, then manufacturing is easier, but ESD discharge efficiency at corners is insufficient
Solution Approach 1:
The invention applies local quality by making short-circuit portions at corner regions different from those in central regions. Specifically, corner short-circuit portions have larger contact hole diameters or greater numbers of contact holes compared to central short-circuit portions. This local differentiation optimizes ESD discharge efficiency at corners where ESD is more likely to occur, while maintaining simpler structures in central regions for easier manufacturing
Solution Approach 2:
The invention introduces asymmetry in the distribution and dimensions of short-circuit portions across the substrate. Corner short-circuit portions are designed with different characteristics (larger contact holes or more contact holes) compared to central short-circuit portions. This asymmetric design optimizes ESD protection where it is most needed at corners, while maintaining manufacturing feasibility through clear differentiation rules
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 configuration effectively reduces damage to switching elements by facilitating the external discharge of ESD, thereby improving the overall ESD tolerance of the LCD device.
Implementation Method 1
a plurality of short-circuit portions between the common line and the common electrode. Each of the plurality of short-circuit portions includes a contact surface contacting the common line, and at least two of the short-circuit portions respectively include contact surfaces having different sizes
Data Source
AI summary
A liquid crystal display (“LCD”) device is improved in terms of electrostatic discharge (“ESD”) tolerance, the LCD device including: a first substrate and a second substrate spaced apart from each other; a liquid crystal layer between the first substrate and the second substrate; a common line on the first substrate; a common electrode on the second substrate; and a plurality of short-circuit portions between the common line and the common electrode. Each of the plurality of short-circuit portions includes a contact surface contacting the common line, and at least two of the short-circuit portions respectively include contact surfaces having different sizes.