Electronic Pen Cartridge Inductive Charging via Rear Coil

Solution Overview

Problem

Existing electronic pens of the active capacitance type require a power supply circuit using primary or secondary batteries, making it difficult to create an electronic pen cartridge compatible with a ballpoint pen refill, as it necessitates a dedicated and expensive primary battery with limited capacity.

Innovation Solution

An electronic pen cartridge with a tubular cartridge housing containing an electronic circuit, a rechargeable power storage device, and a coil wound around the rear end portion, allowing the power storage device to be charged by an induced current from an external magnetic field, thus eliminating the need for frequent battery replacements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a primary battery is mounted in an electronic pen cartridge to supply power, then the electronic pen can operate as an active capacitance type, but the cartridge becomes incompatible with standard ballpoint pen refills and requires frequent battery replacement

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the chemical energy storage system (primary battery) with an electromagnetic energy transfer system. A coil is wound around a ferrite core to form a charging unit that receives electromagnetic induction from an external charging device, converting electromagnetic energy to electrical energy to charge the power storage device. This substitution eliminates the need for a large primary battery while maintaining active capacitance functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent embeds the charging unit (coil and ferrite core) within the electronic pen cartridge structure. The coil is wound around the ferrite core, and this charging unit is integrated into the cartridge housing, allowing the power storage device to be recharged internally without requiring battery replacement or external power connections.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Duration of action of moving object

If a primary battery with sufficient capacity is used, then the electronic pen can operate for extended periods, but the battery becomes expensive and requires a dedicated housing design

Engineering Contradiction:

Core Design Contradiction:

Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent implements a rechargeable power storage device that can be recharged multiple times through the charging unit. Instead of relying on a single-use primary battery with sufficient capacity, the system allows preliminary charging actions to be repeated, extending the operational duration without increasing housing complexity or cost.

Inventive Principle:

Principle #10Preliminary action

3Use of energy by moving object

If a coil is wound around a ferrite core in the cartridge, then the power storage device can be charged by electromagnetic induction, but the cartridge thickness increases

Engineering Contradiction:

Core Design Contradiction:

Use of energy by moving objectVSLength of stationary object

Solution Approach 1:

The patent positions the coil and ferrite core charging unit at the rear end portion of the cartridge housing, concentrating the electromagnetic charging components in a specific local area. This allows the front portion of the cartridge to remain thin and compatible with ballpoint pen refill dimensions, while the rear portion accommodates the charging mechanism.

Inventive Principle:

Principle #3Local quality

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 the electronic pen cartridge to maintain compatibility with a ballpoint pen refill, allowing the housing of a ballpoint pen to be used as is, and provides efficient charging of the power storage device, reducing the need for frequent battery replacements.

Implementation Method 1

a coil wound around an outside of a rear end portion of the cartridge housing... The power storage device is configured to be charged by an induced current that is induced in the coil based on an externally supplied magnetic field

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The electronic pen of the active capacitance type transmits a signal from the signal transmission circuit to a position detection sensor via the conductive axial center body through capacitive coupling

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS12271539B2Electronic pen, electronic pen cartridge, and electronic pen charging tray

Publication Date: 2025.04.08

AI summary

An electronic pen cartridge is replaceable with a refill of a stationery ballpoint pen such that the stationery ballpoint pen housing can be reused as the electronic pen housing. The electronic pen cartridge is of a capacitance type and includes a pen tip which is projectable from an opening on one side in an axial direction of the pen housing. Inside the tubular cartridge housing are an electronic circuit including a signal transmission circuit configured to generate a signal to be supplied to a position detection sensor, and a rechargeable power storage device configured to supply a power supply voltage to the electronic circuit. A coil is wound around a portion of the cartridge housing, the portion located at a position where there is room in the pen housing. The power storage device is charged by a current induced in the coil based on an externally supplied magnetic field.