Liquid Crystal Display Dummy Wiring for ESD Protection
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Solution Overview
Problem
Existing liquid crystal display devices, particularly in FFS mode, face challenges in achieving sufficient electrostatic discharge resistance, leading to issues like decreased contrast and display non-uniformity due to static electricity-induced vertical electric fields.
Innovation Solution
The implementation of a liquid crystal display device design that includes a first substrate with pixel electrodes, a peripheral circuit, and dummy wiring, along with a second substrate featuring a translucent conductive film on its outer surface. The dummy wiring is grounded or connected through protective resistances to manage static electricity effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a translucent conductive film is formed over the entire outer surface of the opposite substrate and connected to ground, then electrostatic discharge resistance is improved, but device complexity increases
Solution Approach 1:
The patent divides the electrostatic discharge protection function into multiple segments: a translucent conductive film on the opposite substrate and separate dummy wiring on the element substrate. This segmentation allows each component to be optimized independently while collectively providing comprehensive ESD protection, resolving the contradiction between reliability improvement and device complexity by distributing the protection function across multiple simplified components.
Solution Approach 2:
The patent introduces dummy wiring as an intermediary component that provides a dedicated electrostatic discharge path separate from the functional peripheral circuit. This intermediary structure allows static electricity to be safely discharged to ground without interfering with the normal operation of the liquid crystal display device, improving reliability while maintaining circuit simplicity through functional separation.
2Reliability
If static electricity is discharged through the peripheral circuit, then electrostatic discharge resistance is improved, but circuit functionality is compromised
Solution Approach 1:
The patent segments the electrostatic discharge path from the functional peripheral circuit by introducing separate dummy wiring. This segmentation ensures that static electricity is discharged through a dedicated path that does not intersect with or interfere with the signal and power lines of the peripheral circuit, simultaneously achieving ESD protection and circuit functionality.
Solution Approach 2:
The patent extracts the electrostatic discharge function from the peripheral circuit by providing a separate dummy wiring path. This extraction allows the peripheral circuit to maintain its original functionality without being compromised by ESD discharge currents, as the harmful static electricity is diverted through the dedicated dummy wiring to ground.
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 significantly enhances the electrostatic discharge resistance of the liquid crystal display device, preventing static electricity from interfering with the liquid crystal alignment and maintaining display quality by reducing contrast decrease and chrominance non-uniformity.
Implementation Method 1
releasing the electrostatic charge to the ground electric potential (GND) of an external circuit
Implementation Method 2
a translucent conductive film is formed over the entire outer surface of the opposite substrate, and this translucent conductive film is connected to a case or an FPC (Flexible Printed Circuit) terminal
Implementation Method 3
The dummy wiring is located on an outer peripheral side of the substrates than the peripheral circuit and is provided independently of the peripheral circuit in terms of circuit. The dummy wiring is grounded outside the first substrate.
Data Source
AI summary
A liquid crystal display device includes a first substrate, a second substrate and liquid crystal. The first substrate includes pixel electrodes, a peripheral circuit and a dummy wiring. The peripheral circuit and the dummy wiring are provided outside a pixel area in which the pixel electrodes are arranged. The second substrate is opposed to the first substrate through the liquid crystal. The second substrate includes a translucent conductive film that is provided on an opposite side of the second substrate to a side where the liquid crystal is present. The dummy wiring is located on an outer peripheral side of the substrates than the peripheral circuit and is provided independently of the peripheral circuit in terms of circuit. The dummy wiring is grounded outside the first substrate.