Position Indicator Cartridge Segmentation for Ferrite Core Strength
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Solution Overview
Problem
Conventional position indicators face challenges in thickness reduction due to the difficulty in forming precise through-holes in ferrite cores, leading to susceptibility to breakages and weak electromagnetic coupling with sensors.
Innovation Solution
A position indicator design featuring a tubular chassis with a core body unit and tubular body unit integrated in a cartridge configuration, where the magnetic core is covered with a protective material to form a pen tip, allowing for thinning without through-holes and enhancing electromagnetic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a through-hole is formed in the ferrite core to insert a core body, then the position indicator can detect writing pressure, but the ferrite core becomes susceptible to breakages and thickness reduction is difficult
Solution Approach 1:
The invention divides the position indicator into two separate functional units: a magnetic core unit containing the ferrite core and coil, and a core body unit containing the writing pressure detector and pen tip. This segmentation allows the ferrite core to be thin and strong without requiring a through-hole, while the core body can be inserted into the magnetic core through magnetic attraction rather than mechanical fitting.
Solution Approach 2:
The invention introduces a magnetic field as an intermediary force to hold the core body unit to the magnetic core unit. Instead of mechanically fixing the core body through a through-hole (which weakens the ferrite), the magnetic field provides the necessary holding force, eliminating the need for a through-hole and preserving the structural integrity of the ferrite core.
2Length of moving object
If the ferrite core is thinned to reduce position indicator thickness, then the overall size is reduced, but forming precise through-holes becomes difficult and breakage risk increases
Solution Approach 1:
The invention separates the ferrite core into a thin magnetic core unit that does not require through-holes, and the core body unit that contains the pen tip and writing pressure detector. This allows the ferrite core to be optimized for thinness and strength independently of the mechanical requirements for pressure detection.
Solution Approach 2:
The invention extracts the core body (pen tip and pressure detector) from the ferrite core structure, allowing the ferrite core to be a separate, thin magnetic component without through-holes. The core body is then attached to the magnetic core through magnetic attraction, enabling thickness reduction without compromising manufacturing precision or structural integrity.
3Measurement precision
If a core body is inserted through a through-hole in the ferrite core, then writing pressure can be detected, but electromagnetic coupling with the sensor becomes weak
Solution Approach 1:
The invention segments the position indicator into a magnetic core unit with the coil and ferrite core, and a core body unit with the pen tip. By keeping the ferrite core intact without through-holes and positioning the coil optimally around it, the electromagnetic coupling between the position indicator and the position detecting device sensor is strengthened while the core body is attached through magnetic attraction for pressure detection.
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
Enables significant thickness reduction while reinforcing the magnetic core, improving electromagnetic coupling and compatibility with commercially available ballpoint pens, reducing the risk of breakages.
Implementation Method 1
The resonant circuit of the position indicator is configured to have a resonant frequency according to the frequency of the transmission signal and stores the electromagnetic energy based on an electromagnetic induction effect between the resonant circuit and the loop coil of the sensor
Implementation Method 2
Then, the position indicator returns the electromagnetic energy stored in the resonant circuit to the loop coil of the sensor of the position detecting device
Implementation Method 3
The loop coil of the sensor detects the electromagnetic energy from this position indicator
Data Source
AI summary
A position indicator includes a tubular chassis in which an opening is made on one end in an axial direction as a pen tip side and another end. A position indicator cartridge is housed in a hollow part of the chassis. The position indicator cartridge includes a core body unit having a coil that forms part of a resonant circuit that is wound partly around a bar-shaped magnetic core, part of the magnetic core around which the coil is not wound forming a pen tip part, and a tubular body unit that houses at least a capacitor that forms part of the resonant circuit. A change circuit also forms part of the resonant circuit and is configured to change a resonant frequency or a phase of the resonant circuit according to a writing pressure applied to the core body unit.