Electronic Pen Resonance Circuit Tuning with Capacitor Array Feedback

Solution Overview

Problem

Existing methods for adjusting the resonance frequency of electronic pens face inefficiencies due to manufacturing errors in capacitors, leading to improper adjustment of the reference resonance frequency, often requiring repeated processes to disconnect capacitors.

Innovation Solution

A method involving an electronic pen with a coil, external capacitor, and integrated circuit containing an internal capacitor array, where the state of capacitive elements is changed to adjust the resonance frequency using an external apparatus for precise capacitance measurement and adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple capacitors are pre-arranged in parallel and lines are cut by laser to disconnect capacitors based on standard capacitance values, then the reference resonance frequency can be matched to the standard value, but the adjustment process becomes inefficient due to manufacturing errors in actual capacitor values

Engineering Contradiction:

Improvereference resonance frequency matchingVSAvoidadjustment process efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-arranging multiple capacitors in parallel with different capacitance values before the adjustment process. This allows the system to have multiple capacitance options available from the start, enabling efficient adjustment without needing to repeatedly add or modify capacitors during the tuning process. The capacitors are prepared in advance with specific capacitance values that cover the expected range of resonance frequency adjustments.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by measuring the actual reference resonance frequency after capacitor selection and using this measurement information to determine which capacitors to connect or disconnect. The system continuously monitors the resonance frequency and adjusts the capacitor configuration based on the measured deviation from the standard value, creating a closed-loop adjustment process that compensates for manufacturing errors in capacitor values.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If capacitor lines are cut by laser based on calculated selections, then the reference resonance frequency can be adjusted, but repeated measurement and adjustment processes are required due to capacitance value variations

Engineering Contradiction:

Improvereference resonance frequency accuracyVSAvoidrepeated adjustment cycles

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-arranging multiple capacitors in parallel with different capacitance values before the adjustment process. This allows the system to have multiple capacitance options available from the start, enabling efficient adjustment without needing to repeatedly add or modify capacitors during the tuning process. The capacitors are prepared in advance with specific capacitance values that cover the expected range of resonance frequency adjustments.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by measuring the actual reference resonance frequency after capacitor selection and using this measurement information to determine which capacitors to connect or disconnect. The system continuously monitors the resonance frequency and adjusts the capacitor configuration based on the measured deviation from the standard value, creating a closed-loop adjustment process that compensates for manufacturing errors in capacitor values.

Inventive Principle:

Principle #23Feedback

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 approach allows for suitably adjusting the reference resonance frequency by estimating capacitance variations, ensuring accurate resonance frequency matching without repeated processes.

Implementation Method 1

When the resonance circuit enters the magnetic field, the coil generates an induced electromotive force that allows the resonance circuit to accumulate electric power

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a method of transmitting the pen information in terms of resonance frequency variations by changing the resonance frequency of the resonance circuit according to the content of the pen information

Methodology Applied

Scientific EffectResonance frequency variation: Resonance

Data Source

PatentUS12498807B2Method for adjusting resonance frequency of resonance circuit included in electronic pen, electronic pen, and method for manufacturing electronic pen

Publication Date: 2025.12.16 WACOM CO LTD

AI summary

A method is provided for adjusting the resonance frequency of a resonance circuit included in an electronic pen. The method uses adjusting means for adjusting the capacitance of an internal capacitor array and measuring means for measuring an alternating magnetic field generated by the resonance circuit. The method includes (1) a step of changing the state of a predetermined portion of multiple capacitive elements constituting the internal capacitor array, and (2) a step of changing, according to reference resonance frequency variations of the resonance circuit before and after the state change, the state of a portion or all of at least one capacitive element constituting the inner capacitor array other than said predetermined portion of the capacitive elements.