Shielding Layer Magnetic Permeability for Touch Sensor Signal Integrity
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Solution Overview
Problem
Existing electronic devices with touch sensors face challenges in maintaining high sensing sensitivity, especially when dealing with resistance differences across the sensing area, which can lead to signal attenuation and reduced accuracy.
Innovation Solution
The implementation of a first shielding layer with higher resistance and magnetic permeability than copper, which is disposed between lower members under the display layer, helps to reduce signal attenuation by providing a magnetic path for the magnetic field emitted from the input device and shielding it from interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional shielding layer (e.g., copper) is used under the display layer, then the device structure is simple and cost-effective, but signal attenuation occurs due to resistance differences across the sensing area, reducing sensing sensitivity
Solution Approach 1:
The patent changes the material parameter of the shielding layer from conventional copper to a material with higher magnetic permeability (such as mu-metal or amorphous alloy). This parameter change enables the shielding layer to provide magnetic flux shunting, which compensates for signal attenuation caused by resistance differences across the sensing area, thereby improving sensing sensitivity without requiring structural modifications
Solution Approach 2:
The shielding layer acts as an intermediary element between the sensor layer and the lower member. By introducing this intermediate layer with high magnetic permeability, the patent creates a magnetic flux path that redirects magnetic field lines away from high-resistance areas, thereby compensating for signal loss without directly modifying the sensor layer or lower member structures
2Area of stationary object
If the sensing area is increased to improve user interaction, then the touch coverage is enhanced, but resistance differences across the larger area cause greater signal attenuation and reduced measurement accuracy
Solution Approach 1:
By changing the magnetic permeability parameter of the shielding layer material, the patent enables effective signal compensation across expanded sensing areas. The high magnetic permeability material creates distributed magnetic flux paths that maintain signal integrity even over larger distances, allowing the sensing area to be increased without sacrificing input coordinate accuracy
3Measurement precision
If a shielding layer with higher magnetic permeability material is used, then sensing sensitivity is improved by compensating signal attenuation, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The shielding layer is designed to serve multiple functions simultaneously: it provides electromagnetic shielding, acts as a magnetic flux shunt for signal compensation, and serves as a structural support element. This multi-functionality reduces the need for additional components and simplifies the overall device architecture, offsetting the increased material complexity
Solution Approach 2:
The patent employs composite material structures where the high magnetic permeability shielding layer is integrated with the lower member or other structural components. This composite approach allows the beneficial magnetic properties to be achieved while maintaining manufacturing feasibility through established composite material fabrication techniques
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 enhances the sensing sensitivity of the sensor layer by compensating for signal attenuation due to resistance differences, ensuring that the current value remains equal to or greater than a predetermined value, even at points of greatest resistance.
Implementation Method 1
providing a magnetic path for the magnetic field emitted from the input device and shielding it from interference
Implementation Method 2
shielding layer with higher resistance and magnetic permeability than copper, which is disposed between lower members under the display layer, helps to reduce signal attenuation by providing a magnetic path for the magnetic field
Implementation Method 3
a resonator that generates the magnetic field according to the signal
Implementation Method 4
a resonator that generates the magnetic field according to the signal
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An electronic device includes a display layer, a sensor layer disposed on the display layer, and a lower member that is disposed under the display layer and includes a first shielding layer. The sensor layer operates in a first touch mode for sensing a first input based on a capacitance change and a second touch mode for sensing a second input of an input device that is configured to emit a magnetic field, and the first shielding layer shields the magnetic field that is transmitted through the sensor layer.