Magnetic Path Plate for Position Detector Noise Shielding
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Solution Overview
Problem
The integration of a pen tablet in mobile electronic devices is hindered by electromagnetic interference from metallic components in the electronic circuit, leading to attenuation of the magnetic field and noise interference, which affects the accuracy of position detection and increases the device's weight and cost.
Innovation Solution
A magnetic path plate using an amorphous layer and aluminum, with relative magnetic permeability lower than the amorphous layer, is employed to act as electromagnetic shielding, preventing attenuation of the magnetic field and reducing noise interference while maintaining a lightweight and cost-effective design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a magnetic path plate is used for electromagnetic shielding, then noise interference is reduced, but the magnetic field is attenuated
Solution Approach 1:
The magnetic path plate is divided into multiple regions with different magnetic permeabilities: a first region with high magnetic permeability for shielding electromagnetic noise, and a second region with low magnetic permeability for transmitting the magnetic field to the sensor. This segmentation allows the plate to simultaneously perform noise shielding and magnetic field transmission functions.
Solution Approach 2:
Different regions of the magnetic path plate are assigned different local properties (magnetic permeability values) according to their specific functional requirements. The first region has high magnetic permeability to attract and shield external magnetic noise, while the second region has low magnetic permeability to allow the sensor's magnetic field to pass through to the detection surface.
2Object-affected harmful factors
If conventional electromagnetic shielding materials are used, then noise interference is reduced, but the device weight increases
Solution Approach 1:
The magnetic path plate uses a composite structure combining materials with different magnetic permeability characteristics. This composite approach provides effective electromagnetic shielding while maintaining a lightweight design, avoiding the need for heavy conventional shielding materials.
3Object-affected harmful factors
If conventional electromagnetic shielding materials are used, then noise interference is reduced, but the device cost increases
Solution Approach 1:
The magnetic path plate employs a composite material structure that achieves effective electromagnetic shielding at lower cost. By using materials with appropriate magnetic permeability differences and optimizing their arrangement, the design reduces manufacturing costs compared to conventional shielding solutions.
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 magnetic path plate effectively shields the sensor coils from electromagnetic noise, enhancing the accuracy of position detection and reducing the overall weight and cost of the mobile electronic device without attenuating the magnetic field, thus improving the pen tablet's performance and portability.
Implementation Method 1
the sensor coil 21 receives an electromagnetic wave output from the position indicator 10
Implementation Method 2
the magnetic path plate 30 functions to prevent the sensor coil 21 from receiving electromagnetic noise
Data Source
AI summary
A position detector is disclosed, which includes a sensor substrate having a sensor coil for receiving an electromagnetic wave output from a position indicator, and a magnetic path plate that has an area equal to or larger than an area in which the sensor coil is arranged on the sensor substrate. The magnetic path plate is formed by stacking an amorphous layer and a non-amorphous layer, which is formed of metal with relative magnetic permeability lower than that of the amorphous layer. Such magnetic path plate is arranged on a side of the sensor substrate opposite to a side facing the position indicator.