Position Detection Device Shield Layer Noise Reduction
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Solution Overview
Problem
Position detection devices with electromagnetic induction type sensors face issues with magnetic field attenuation and noise interference due to the proximity of electronic circuits, particularly in compact mobile devices where space constraints and increased component density exacerbate these problems.
Innovation Solution
A position detection device configuration with a sensor-substrate main body having electrodes on both surfaces, a shield layer covering the electrodes on the opposing surface, and a circuit board connected to the cable section on the same surface as the sensor-substrate main body, ensuring the connection portion is not exposed and reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the position detection sensor and electronic circuit are arranged in close proximity in an overlapping manner, then the device complexity is reduced and space is saved, but the magnetic field is attenuated and noise interference increases
Solution Approach 1:
A magnetic path plate is introduced as an intermediary component between the position detection sensor and the electronic circuit. This plate serves as a mediator that guides magnetic field lines through its high-permeability material structure, preventing direct interference between the sensor and circuit while maintaining compact arrangement. The magnetic path plate effectively isolates the sensor from electronic noise without requiring increased separation distance.
Solution Approach 2:
The electronic circuit, which generates electromagnetic noise that interferes with the sensor, is positioned in close proximity to the sensor. By introducing the magnetic path plate, the harmful electromagnetic interference is converted into a beneficial arrangement where the plate's magnetic shielding properties protect the sensor while allowing compact integration. The proximity that causes harm is transformed into an opportunity for efficient space utilization with proper shielding.
2Volume of moving object
If the position detection sensor and electronic circuit are arranged in close proximity in an overlapping manner, then space is saved in compact devices, but magnetic field attenuation occurs and noise affects coordinate detection accuracy
Solution Approach 1:
The magnetic path plate acts as a mediator that preserves measurement precision despite close proximity arrangement. By providing a dedicated magnetic flux path through its structured design, it prevents noise from the electronic circuit from reaching the sensor, thereby maintaining coordinate detection accuracy while enabling compact device volume.
Solution Approach 2:
The magnetic path plate is divided into multiple regions with different functions: some regions provide magnetic shielding for the sensor, while other regions guide magnetic field lines away from the electronic circuit. This segmentation allows the plate to simultaneously protect the sensor from noise and maintain efficient magnetic field coupling for accurate position detection, all within a compact form factor.
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 effectively prevents noise from entering or being emitted, enhancing the reliability of the position detection device by maintaining the integrity of the magnetic field and reducing electromagnetic interference, suitable for integration in mobile devices.
Implementation Method 1
a shield layer configured to cover the electrodes formed on the second surface
Implementation Method 2
the position detection sensor of, for example, an electromagnetic induction type
Data Source
AI summary
A position detection device includes a position detection sensor that is used with a position indicator and includes a sensor-substrate main body including electrodes and a cable section to which the electrodes are led out. The position detection device includes a circuit board including a position detection circuitry to which the position detection sensor is connected. The sensor-substrate main body includes an insulating substrate having a first surface that is located on a side where a position is to be indicated by the position indicator and a second surface opposite from the first surface. The circuit board is connected to the cable section on a surface of the cable section contiguous with the first surface of the sensor-substrate main body, and when the cable section is bent toward the second surface of the sensor-substrate main body, the circuit board is positioned at a lowermost layer of the position detection device.