Planar Coil Position Detection for Electronic Pen Waterproofing
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Solution Overview
Problem
Existing position detection devices in mobile information terminals face challenges in achieving a waterproof specification, simplifying the fabrication process, reducing thickness, and minimizing power consumption, especially when using electromagnetic induction type sensors.
Innovation Solution
A position detection device with a planar coil disposed adjacent to an accommodation portion for an electronic pen, where the planar coil's center axis crosses the axial direction of the electronic pen, allowing for efficient signal transfer and detection of the pen's accommodation state without mechanical or magnetic switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical switch is used to detect electronic pen accommodation, then the detection function is achieved, but waterproof specification cannot be implemented due to gaps at the switch portion
Solution Approach 1:
The patent replaces the mechanical switch with an electromagnetic induction-based detection system. A coil is provided in the accommodation portion to detect the electronic pen through electromagnetic induction, eliminating mechanical components that create gaps and enable waterproof design while maintaining detection functionality.
Solution Approach 2:
The patent introduces a coil as an intermediary detection element between the electronic pen and the detection system. The coil detects the electronic pen's presence through electromagnetic induction without requiring direct mechanical contact or creating gaps, thus enabling waterproof specification.
2Reliability
If a magnet is incorporated in the electronic pen with a magnetic sensor on the terminal, then accommodation detection is achieved, but the magnet influences the resonance circuit and position detection circuits
Solution Approach 1:
The patent replaces the magnetic field-based detection system with an electromagnetic induction-based system using a coil. This substitution eliminates the need for magnets in the electronic pen, removing the source of magnetic interference with resonance and position detection circuits while maintaining accommodation detection capability.
3Ease of operation
If the electromagnetic induction type sensor is kept operative to enable fine input by electronic pen, then the detection function is available, but battery power is exhausted faster
Solution Approach 1:
The patent implements a dynamic control system where the electromagnetic induction type sensor is activated only when the electronic pen is detected in the accommodation portion. The control circuit switches between capacitive type sensor operation (for general touch input) and electromagnetic induction type sensor operation (for fine input with electronic pen), optimizing power consumption based on usage mode.
4Reliability
If a coil is disposed in the accommodation portion to cover the electronic pen coil, then electromagnetic induction detection works, but the fabrication process becomes complicated and thickness increases
Solution Approach 1:
The patent designs the coil in the accommodation portion to serve multiple functions: it detects the electronic pen's presence through electromagnetic induction and also functions as part of the position detection system. This multi-functionality reduces the need for separate components, simplifying fabrication and reducing overall thickness.
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 enables efficient signal transfer between the electronic pen and the planar coil, allows for accurate detection of the pen's accommodation state, and facilitates a waterproof design while reducing the complexity of the fabrication process and minimizing power consumption.
Implementation Method 1
A first control circuit controls supply processes in which a first signal is supplied to the planar coil and reception processes in which a second signal is received through the planar coil by electromagnetic induction are performed alternately
Implementation Method 2
a second signal is received through the planar coil by electromagnetic induction
Data Source
AI summary
A position detection device includes a main body with a housing that encloses an electronic pen while the electronic pen is accommodated in an accommodation portion included in the housing, and a planar coil having a rectangular cross-sectional area and disposed adjacent to the accommodation portion at a position at which a direction perpendicular to the rectangular cross-sectional area of the planar coil crosses an axial direction of the electronic pen while the electronic pen is accommodated in the accommodation portion.