Touch Device Shielding Layer for Peripheral Interference
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Solution Overview
Problem
Conventional touch display panels suffer from signal interference due to induced capacitance at the peripheral area, leading to erroneous touch operations when the device is held by one hand and operated by another.
Innovation Solution
A touch device with a sensing area and a peripheral area features a touch-sensing layer, a shielding layer separated from the touch-sensing layer, and an insulating layer in between, along with a conductive layer that reduces impedance and enhances shielding, effectively isolating the induced capacitance from the signal conveying traces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signal traces are disposed at the peripheral area to convey touch signals, then the touch signals can be transmitted from the sensing electrodes to external circuits, but the signal traces are interfered by induced capacitance generated when the device is held by one hand and operated by another
Solution Approach 1:
An insulating layer is introduced as an intermediary between the touch-sensing layer (containing sensing electrodes) and the shielding layer (containing signal traces). This insulating layer mediates the interaction between the two layers, preventing direct capacitive coupling while allowing signal transmission through the shielding layer to external circuits, thereby reducing induced capacitance interference on the touch signals
Solution Approach 2:
The touch device is segmented into functionally distinct layers: a touch-sensing layer for detecting touch input, an insulating layer for electrical isolation, and a shielding layer for signal transmission. This segmentation allows each layer to perform its specific function independently, with the insulating layer specifically addressing the interference problem by separating the sensing electrodes from the signal traces
2Measurement precision
If a shielding layer is added at the peripheral area to reduce induced capacitance interference, then the touch signal accuracy is improved, but the device structure and fabrication process become more complex
Solution Approach 1:
The shielding layer serves multiple functions simultaneously: it acts as an electrical shield to block induced capacitance interference from reaching the signal traces, and it also serves as a structural support layer that can be integrated with the overall device architecture. This multi-functionality reduces the need for additional separate shielding components, thereby limiting the increase in device complexity
Solution Approach 2:
The insulating layer is nested between the touch-sensing layer and the shielding layer, creating a compact multi-layer structure where each layer is integrated within the others. The signal traces are nested within the shielding layer, which itself is nested within the overall device structure. This nested arrangement achieves effective shielding while maintaining a compact form factor and manageable fabrication process
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 solution effectively shields interference at the peripheral area, ensuring accurate touch operations by conveying induced capacitance to a ground terminal, thereby preventing erroneous actions and enhancing the reliability of touch inputs.
Implementation Method 1
an insulating layer disposed between the touch-sensing layer and the shielding layer
Implementation Method 2
a shielding layer disposed at the peripheral area of and separated from the touch-sensing layer
Implementation Method 3
A conductive layer is disposed on the induced layer and electrically connected with the induced layer
Data Source
AI summary
A touch device is provided. The touch device, having a sensing area and a peripheral area, includes a touch-sensing layer, a shielding layer disposed at the peripheral area of and separated from the touch-sensing layer, and an insulating layer disposed between the touch-sensing layer and the shielding layer. Moreover, a fabrication method of a touch device is provided.