Transparent Shielding Layer for In-Cell Touch LCD Electrostatic Disruption
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Solution Overview
Problem
Liquid crystal displays are susceptible to disruptions from electrostatic charges, which can create electric fields that interfere with the operation of the display, especially when touch sensor electrodes are located below the liquid crystal layer, as they do not effectively prevent charge-induced electric fields from reaching the liquid crystal layer.
Innovation Solution
Incorporating one or more transparent electric field shielding layers above the liquid crystal layer, formed from conductive materials such as metal oxides, conductive polymers, or carbon nanotubes, with controlled resistivity to prevent disruptions while allowing touch sensor functionality, and using conductive rings or switches to ground the shielding layer effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If touch sensor electrodes are located below the liquid crystal layer, then the display can achieve in-cell configuration, but the display becomes susceptible to disruptions from electrostatic charges
Solution Approach 1:
A transparent electric field shielding layer is introduced as an intermediary component between the external environment and the liquid crystal layer. This shielding layer, formed from conductive materials such as metal oxides, conductive polymers, or carbon nanotubes, acts as a mediator that blocks electrostatic charge-induced electric fields from reaching the liquid crystal layer, thereby protecting the display while maintaining the in-cell configuration
Solution Approach 2:
The shielding layer is constructed using composite conductive materials that combine transparency with electrical conductivity. These materials, including metal oxides, conductive polymers, and carbon nanotubes, create a composite structure that simultaneously provides electrostatic shielding and maintains optical transparency, allowing the display to function properly while protecting against electrostatic disruptions
2Object-affected harmful factors
If a conductive shielding layer is added above the liquid crystal layer, then electrostatic charge-induced electric fields are blocked, but the resistivity must be carefully controlled to maintain touch sensor functionality
Solution Approach 1:
The resistivity of the shielding layer is precisely controlled and optimized to a specific range that allows it to block electrostatic charge-induced electric fields while simultaneously permitting the passage of touch sensor signals. By adjusting the resistivity parameter of the conductive material, the shielding layer achieves dual functionality: protecting against electrostatic disruptions and maintaining touch sensor operation
Solution Approach 2:
The shielding layer exhibits different electrical properties at different locations and for different types of electrical signals. It provides high impedance to electrostatic charge-induced electric fields while maintaining appropriate conductivity for touch sensor signals, achieving location and signal-type dependent electrical characteristics that satisfy both protection and functionality requirements
3Object-affected harmful factors
If the shielding layer resistivity is too low, then electrostatic charge is effectively blocked, but touch sensor operation may be interfered with
Solution Approach 1:
The resistivity of the shielding layer is precisely controlled and optimized to a specific range that allows it to block electrostatic charge-induced electric fields while simultaneously permitting the passage of touch sensor signals. By adjusting the resistivity parameter of the conductive material, the shielding layer achieves dual functionality: protecting against electrostatic disruptions and maintaining touch sensor operation
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
The shielding layers effectively prevent electrostatic charge-induced electric fields from disrupting the liquid crystal layer operation while maintaining touch sensor functionality, ensuring stable and clear display performance.
Implementation Method 1
one or more transparent electric field shielding layers may be incorporated into the display above the liquid crystal layer... The shielding layers may be formed from conductive adhesive, metal oxides, conductive polymers, materials that include nanostructures such as carbon nanotubes
Implementation Method 2
The shielding layers may be formed from conductive adhesive, metal oxides, conductive polymers, materials that include nanostructures such as carbon nanotubes... and using conductive rings or switches to ground the shielding layer effectively
Data Source
AI summary
Displays such as liquid crystal displays may be used in electronic devices. During operation of a display, electrostatic charges on the surface of the display may give rise to electric fields. One or more electric field shielding layers may be provided in the display to prevent the electric fields from disrupting operation of the liquid crystals material in the display. The shielding layers may be formed at a location in the stack of layers that make up the display that is above the liquid crystal material of the display. Touch sensors and thin film transistors may be located below the shielding layer.