Position Indicator With Shared Ferrite Core

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Solution Overview

Problem

The existing electronic pens with interchangeable cartridges face interference issues due to adjacent resonance circuits and high costs due to the need for coils and circuits in each cartridge, making them expensive and prone to malfunction.

Innovation Solution

A position pointer design that accommodates two refill bodies within a single housing, where only one is projected at a time, using a common ferrite core and coil, and variable capacitors for writing pressure detection, eliminating the need for special cartridges and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple position pointer cartridges with resonance circuits are accommodated in a single housing, then multi-color and multi-function capabilities are improved, but signal interference between adjacent resonance circuits occurs and device complexity increases

Engineering Contradiction:
Improvemulti-color and multi-function capabilitiesVSAvoidsignal interference between resonance circuits
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the resonance circuit components (coil and ferrite core) from individual cartridges and relocates them to a common housing structure. This separation allows multiple cartridges to be accommodated without each containing its own resonance circuit, thereby eliminating signal interference while maintaining multi-functionality through the shared resonance circuit architecture.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the resonance circuit components into a single common housing that serves multiple cartridges. The coil and ferrite core are shared among multiple cartridges, allowing them to function together as a unified system rather than independent units, which reduces complexity and eliminates interference.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If coils and circuits are incorporated in each cartridge, then individual cartridge functionality is improved, but manufacturing cost increases

Engineering Contradiction:
Improveindividual cartridge functionalityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent makes the housing and resonance circuit components universal by designing them to support multiple different cartridge types. The common housing with shared coil and ferrite core can accommodate various cartridges (ballpoint, electronic pen, etc.), eliminating the need for dedicated resonance circuits in each cartridge type and reducing manufacturing costs through component standardization.

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

Solution Approach 2:

Instead of replicating expensive resonance circuit components in each cartridge, the patent uses a single set of coil and ferrite core components that serve multiple cartridges. This copying approach allows multiple cartridges to benefit from the same resonance circuit infrastructure, significantly reducing per-unit manufacturing costs.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If multiple position pointer cartridges are accommodated in a single housing, then versatility is improved, but the housing structure becomes more complex

Engineering Contradiction:
ImproveversatilityVSAvoidhousing structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the position pointer into two distinct parts: a simple common housing containing the resonance circuit components, and interchangeable cartridges that can be easily removed and replaced. This segmentation allows the housing to remain structurally simple while achieving versatility through the modular cartridge system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic configurability to the housing structure, allowing it to adapt to different cartridge types through a knocking mechanism that selectively projects the desired cartridge. This dynamic element enables the housing to serve multiple functions without requiring complex internal structures for each possible configuration.

Inventive Principle:
Principle #15Dynamics

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 allows for low-cost production, reduces signal interference, and enables efficient operation with interchangeable refill bodies, such as ballpoint and electronic pen refills, without the need for complex cartridges.

Implementation Method 1

a coil 162 wound around the ferrite core 161... exchange electromagnetically induced signals with a sensor section of a position detection device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

variable capacitors for writing pressure detection

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3252571B1Position indicator
Publication Date: 2021.03.03 WACOM CO LTD
  • EP3252571B1 patent drawingFigure 1
  • EP3252571B1 patent drawingFigure 2(A)~2(B)
  • EP3252571B1 patent drawingFigure 3

AI summary

There is provided a position pointer having a plurality of refill bodies that can be configured at low cost and ensure freedom from malfunction during exchange of signals with a sensor section of a position detection device. The position pointer includes a tubular housing having an opening portion on one end side, a plurality of refill bodies accommodated in the housing, a refill body selection mechanism section that selectively causes at least a tip of one of the plurality of refill bodies to project from the opening portion, and a magnetic material core disposed on the one end side of the housing having the opening portion, and a coil is wound around the magnetic material core. The magnetic material core has a through hole into which and through which one of the plurality of refill bodies can be inserted and that communicates with the opening portion. The refill bodies not selected by the refill body selection mechanism section are located away from the through hole of the magnetic material core, and at least the tip of the refill body selected by the refill body selection mechanism section is caused to project externally from the opening portion via the through hole.