Position Indicator Shock-Absorbing Ferrite Core Design

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Solution Overview

Problem

Ferrite cores and rods in existing position indicators are prone to damage from external impact forces due to their inability to absorb or alleviate such forces, leading to potential malfunction of the device.

Innovation Solution

A shock-absorbing member made of elastic material, such as silicon rubber, is attached to the ferrite core to absorb or alleviate external impact forces, and the position detecting coil is N-fold wound around the ferrite core to maintain a strong magnetic field, with the use of magnetic-plated wire to reduce proximity effect-induced attenuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a ferrite core and rod are used in the position indicator, then the magnetic field intensity is increased and position detection accuracy is improved, but the device becomes vulnerable to damage from external impact forces

Engineering Contradiction:
Improveposition detection accuracyVSAvoidresistance to impact force
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A shock-absorbing member is attached to the ferrite core in advance to provide cushioning protection. This member is configured to absorb or alleviate impact forces before they can damage the ferrite core and rod, thereby protecting the fragile components while maintaining position detection functionality.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The position indicator combines the ferrite core (for magnetic field enhancement) with a shock-absorbing member (for impact protection). This composite structure integrates components with different functions - one optimized for magnetic performance and another for mechanical protection - allowing both high measurement precision and improved reliability.

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If the position detecting coil is wound around the ferrite core to increase magnetic field intensity, then position detection accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improveposition detection accuracyVSAvoidstructural complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The ferrite core serves multiple functions: it concentrates and enhances the magnetic field for position detection, and it provides a structural platform for mounting the shock-absorbing member. This multi-functionality reduces the need for additional separate components, thereby managing device complexity while maintaining high measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 shock-absorbing member prevents damage to the ferrite core and rod from impact, while N-fold winding and magnetic-plated wire ensure a strong magnetic field for accurate position detection, enhancing the device's durability and detection sensitivity.

Implementation Method 1

A shock-absorbing member made of elastic material, such as silicon rubber, is attached to the ferrite core to absorb or alleviate external impact forces

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

there is a drive method called 'electromagnetic induction method' in which the position indicator is provided with a resonant circuit, which resonates with an electromagnetic wave of a specified frequency transmitted from the position detecting device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

the position detecting coil is N-fold wound around the ferrite core to maintain a strong magnetic field, with the use of magnetic-plated wire to reduce proximity effect-induced attenuation

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP2045696B1Position indicator and coordinate input device
Publication Date: 2013.11.13 WACOM CO LTD
  • EP2045696B1 patent drawingFigure 1
  • EP2045696B1 patent drawingFigure 2
  • EP2045696B1 patent drawingFigure 3

AI summary

A position indicator includes a case (2), and a rod (3) housed in the case (2). The rod (3) is passed through a cylindrical ferrite core (6) so that its indicating portion (31) (e.g., pen tip) protrudes from an end of the ferrite core (6). A position detecting coil (4) is wound around the periphery of the ferrite core (6). A switch section (5) (e.g., pressure detector) for detecting the pen pressure of the rod (3) is arranged on the other end of the ferrite core (6). An elastic shock-absorbing member (7) is also attached to the other end of the ferrite core (6), so that the shock-absorbing member (7) is fitted between the ferrite core (6) and the switch section (5). Since any impact force applied to the ferrite core (6) and the rod (3) is alleviated by the shock-absorbing member (7), damage to the ferrite core (6) and the rod (3) can be prevented or reduced.