In-Cell Touch Panel Shielding Layer Noise Isolation
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Solution Overview
Problem
In-cell touch panels face noise interference and reduced accuracy due to finger pressure causing uncertain capacitance changes between self-capacitive electrodes and metal layers, leading to decreased signal-to-noise ratio and touch sensing accuracy.
Innovation Solution
A touch panel structure incorporating a transparent conductive layer as a shielding layer, which forms capacitors with a metal layer below, allowing the touch detection chip to detect changes in capacitance only between the shielding layer and the metal layer, thereby isolating the touch detection electrodes from deformation-induced capacitance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If self-capacitive electrodes are used for touch detection, then touch sensing accuracy is improved, but noise interference from finger pressure increases
Solution Approach 1:
The patent segments the conductive layer into two distinct parts: touch detection electrodes for sensing touch positions and transparent conductive regions serving as shielding layers. This segmentation allows the shielding regions to isolate the detection electrodes from capacitance changes caused by finger pressure, thereby reducing noise interference while maintaining touch sensing accuracy.
Solution Approach 2:
The patent introduces transparent conductive regions as intermediary shielding layers between the finger and the touch detection electrodes. These shielding layers act as mediators that block the harmful capacitance changes from propagating to the detection electrodes, thus reducing noise interference without affecting the touch detection function.
2Measurement precision
If shielding layer is added to reduce noise, then touch sensing accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the conductive layer serve multiple functions: it acts as both the touch detection electrode and the shielding layer in different regions. This multi-functionality reduces device complexity by eliminating the need for separate shielding structures while still achieving noise reduction and improved touch sensing accuracy.
Solution Approach 2:
The patent uses the same transparent conductive material for both the touch detection electrodes and the shielding layers, maintaining material homogeneity. This approach simplifies the manufacturing process and reduces device complexity while still providing effective noise shielding to improve touch sensing accuracy.
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 solution effectively improves the accuracy of touch sensing by isolating the capacitance changes caused by finger pressure from the touch detection electrodes, enhancing the signal-to-noise ratio and maintaining the structural integrity and light transmittance of the touch panel.
Implementation Method 1
a transparent conductive layer arranged on a side of the array substrate away from the opposite substrate, where the transparent conductive layer functions as a shielding layer
Implementation Method 2
The existing in cell touch panel detects a finger touching position based on mutual capacitance principle or self capacitance principle
Data Source
AI summary
A touch panel, a display device and a driving method thereof are provided. In the touch panel, a transparent conductive layer is arranged on a side of an array substrate away from an opposite substrate. The transparent conductive layer, functioning as a shielding layer, and touch detection electrodes are applied with an identical touch detection signal at a touch stage. A capacitor is formed by the shielding layer and a metal layer below the touch panel, and a change in distance from the touch panel to the metal layer due to deformation of the touch panel pressed by a finger only affects capacitance between the shielding layer and the metal layer and causes a change in the touch detection signal applied to the shielding layer, while capacitances of the touch detection electrodes are not affected. Therefore, the accuracy of touch sensing is effectively improved.