In-cell Touch Panel Static Discharge via Segmented Shielding
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Solution Overview
Problem
In-cell touch panels face issues with static electricity affecting both display and touch detection sensitivity due to high sheet resistance of transparent conductive films, which impede quick discharge and enhance sensitivity deterioration.
Innovation Solution
An in-cell touch panel design featuring a conductive shielding layer with a higher sheet resistance overlapping the touch detection region and a conductive layer with a lower sheet resistance in the frame region, electrically connected to a reference potential, facilitates quick discharge of static electricity while maintaining high touch detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sheet resistance of the transparent conductive film is increased to maintain touch detection sensitivity, then sensitivity deterioration is suppressed, but static electricity discharge time increases and the effect of static electricity on display and touch detection worsens
Solution Approach 1:
The conductive film is divided into two separate layers: a shielding layer with high sheet resistance (10^7 to 10^9 Ω/sq) positioned over the touch detection region to maintain sensitivity, and a frame conductive layer with low sheet resistance (10^-1 to 10^3 Ω/sq) positioned in the frame region to enable rapid static electricity discharge. This segmentation allows each layer to optimize for its specific function without compromise.
Solution Approach 2:
Different regions of the conductive structure are assigned different electrical properties: the shielding layer in the touch detection region has high sheet resistance to minimize impact on touch sensitivity, while the frame conductive layer has low sheet resistance to maximize static electricity discharge capability. This local differentiation of electrical properties resolves the contradiction between sensitivity and static electricity management.
2Reliability
If the sheet resistance of the transparent conductive film is decreased to improve static electricity discharge, then static electricity effect is reduced, but touch detection sensitivity deteriorates
Solution Approach 1:
The conductive film is divided into two separate layers: a shielding layer with high sheet resistance (10^7 to 10^9 Ω/sq) positioned over the touch detection region to maintain sensitivity, and a frame conductive layer with low sheet resistance (10^-1 to 10^3 Ω/sq) positioned in the frame region to enable rapid static electricity discharge. This segmentation allows each layer to optimize for its specific function without compromise.
Solution Approach 2:
Different regions of the conductive structure are assigned different electrical properties: the shielding layer in the touch detection region has high sheet resistance to minimize impact on touch sensitivity, while the frame conductive layer has low sheet resistance to maximize static electricity discharge capability. This local differentiation of electrical properties resolves the contradiction between sensitivity and static electricity management.
3Measurement precision
If a single transparent conductive film is used with high sheet resistance to maintain sensitivity, then touch detection sensitivity is preserved, but the duration of static electricity discharge is prolonged
Solution Approach 1:
The conductive film is divided into two separate layers: a shielding layer with high sheet resistance (10^7 to 10^9 Ω/sq) positioned over the touch detection region to maintain sensitivity, and a frame conductive layer with low sheet resistance (10^-1 to 10^3 Ω/sq) positioned in the frame region to enable rapid static electricity discharge. This segmentation allows each layer to optimize for its specific function without compromise.
Solution Approach 2:
Different regions of the conductive structure are assigned different electrical properties: the shielding layer in the touch detection region has high sheet resistance to minimize impact on touch sensitivity, while the frame conductive layer has low sheet resistance to maximize static electricity discharge capability. This local differentiation of electrical properties resolves the contradiction between sensitivity and static electricity management.
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 reduces the impact of static electricity on both display and touch detection while preventing sensitivity deterioration, ensuring effective and rapid discharge of static electricity.
Implementation Method 1
a conductive layer (40) having a lower sheet resistance value than the sheet resistance value of the shielding layer (30), and that is electrically connected to the shielding layer (30)
Implementation Method 2
a shielding layer (30) having a sheet resistance value of 1.0×10^7Ω/sq. or higher and 1.0×10^9Ω/sq. or lower, and that is disposed between the touch electrode (11) and the touch surface (70a)
Data Source
AI summary
An in-cell touch panel includes a touch electrode, a shielding layer that is conductive and that is disposed between the touch electrode and the touch surface, a conductive layer that is electrically connected to the shielding layer, and a conductive member and a wiring portion that connect the conductive layer to a reference potential. At least part of the shielding layer is disposed so as to overlap a touch detection region. At least part of the conductive layer is disposed so as to overlap a frame region. A sheet resistance value of the conductive layer is lower than a sheet resistance value of the shielding layer.