Touch-Sensing Display Anti-Static Layer for Capacitive Detection
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Solution Overview
Problem
Touch sensing capabilities are hindered in IPS and FFS mode LCD devices due to the anti-static layer made of transparent conductive materials like ITO and IZO, which causes static electricity discharge, preventing the detection of capacitance changes generated by user touch.
Innovation Solution
Incorporating an anti-static layer on the outer side of the upper substrate comprising an organic material and carbon nano-tubes, with a sheet resistance of about 106 to 109 ohms per square, allowing for effective static electricity dissipation while enabling touch sensing by forming a capacitor between the finger and the common electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an anti-static layer made of transparent conductive materials (ITO, IZO) is used, then static electricity protection is achieved, but touch sensing capability is lost due to capacitance discharge
Solution Approach 1:
The patent changes the electrical parameters of the anti-static layer by using organic conductive materials with adjustable conductivity. By controlling the doping level and molecular structure of the organic material, the sheet resistance can be optimized to allow touch sensing while maintaining static protection. This parameter adjustment resolves the contradiction between static electricity dissipation and capacitance change detection.
Solution Approach 2:
The patent employs composite materials combining organic conductive materials with specific molecular structures and doping agents. This composite approach creates a multi-functional anti-static layer that simultaneously provides static electricity protection and maintains touch sensing capability, resolving the contradiction between these two requirements.
2Reliability
If a conventional anti-static layer is used, then device protection from static damage is achieved, but accurate touch detection becomes impossible
Solution Approach 1:
The organic conductive material acts as an intermediary layer between the transparent substrate and the touch surface. It mediates between the conflicting requirements of static protection and touch sensing by providing a controlled electrical pathway that dissipates harmful static charges while allowing capacitive coupling for touch detection. This intermediary function resolves the contradiction between device protection and measurement precision.
3Reliability
If transparent conductive materials with low sheet resistance are used for anti-static purposes, then static electricity is effectively dissipated, but the material interferes with touch sensing by discharging capacitance
Solution Approach 1:
The patent optimizes the electrical parameters of the organic conductive material by adjusting doping concentration, molecular weight, and chain structure. This allows precise control of sheet resistance to achieve the optimal balance between static dissipation and touch sensing, transforming the harmful capacitance discharge effect into a useful touch detection mechanism.
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 anti-static layer with carbon nano-tubes effectively manages static electricity, allowing for accurate touch detection without device damage, as it serves as a dielectric layer during touch events, enabling the operation of touch sensing LCD devices without compromising on static protection.
Implementation Method 1
an anti-static layer on an outer side of the second substrate and including an organic material and a carbon nano-tube
Implementation Method 2
allowing for effective static electricity dissipation while enabling touch sensing by forming a capacitor between the finger and the common electrode
Data Source
AI summary
A display device includes a first substrate; a second substrate facing the first substrate; a plurality of first electrodes and a plurality of second electrodes disposed between the first substrate and the second substrate; a third electrode on an outer side of the first substrate or the second substrate, the third electrode including an organic material and a carbon nano-tube; a plurality of first conductive lines extending along a first direction; a plurality of second conductive lines extending along the first direction; a plurality of third conductive lines extending along a second direction; and a thin film transistor including a semiconductor layer, a gate electrode, a source electrode, and a drain electrode. A sheet resistance of the third electrode may be greater than a sheet resistance of each of the plurality of first electrodes and a sheet resistance of each of the plurality of second electrodes.