Electronic Pen Resonance Circuit for Digitizer-Free Magnetic Input

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Solution Overview

Problem

Existing electronic devices lack efficient and intuitive input methods beyond keyboards and mice, particularly for multimedia devices, where an electronic pen capable of intuitive input and command execution is needed.

Innovation Solution

An electronic pen with a signal generator, power supply, and resonance circuit that operates as both active and passive types, generating and detecting magnetic fields to communicate with interface devices, and includes a pressure detector for varying signal frequency based on applied pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electronic pen uses an active type with signal generator and resonance circuit, then communication capability and input precision are improved, but device complexity and power consumption increase

Engineering Contradiction:
Improvecommunication capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electronic pen dynamically switches between active and passive operation modes. In active mode, the signal generator and resonance circuit are activated for precise communication. In passive mode, these components remain inactive to reduce complexity and power consumption. This dynamic adaptability allows the pen to optimize performance based on operational requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The electronic pen is designed with multi-functionality to operate in both active and passive modes. The resonance circuit can function as either an active transmitter or a passive detector depending on the operational context. This universal design enables the pen to communicate with different types of interface devices (those with digitizers and those without) using the same hardware architecture.

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

2Power

If an electronic pen operates as active type with signal generator, then signal transmission capability is improved, but power consumption increases

Engineering Contradiction:
Improvesignal transmission capabilityVSAvoidbattery consumption
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The signal generator operates periodically rather than continuously. The control circuit activates the signal generator only during necessary communication intervals, allowing the resonance circuit to charge and discharge in periodic cycles. This periodic operation maintains signal transmission capability while significantly reducing average power consumption compared to continuous operation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The electronic pen dynamically switches between active and passive operation modes based on communication requirements. During active mode, the signal generator transmits signals at full power. During passive mode, the pen detects external magnetic fields without active transmission. This dynamic switching optimizes the balance between signal transmission capability and power consumption.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If an electronic pen includes pressure detector and signal generator, then input precision and control capability are improved, but device complexity increases

Engineering Contradiction:
Improvepressure detection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The pressure detector is integrated with the resonance circuit in a unified architecture. The pressure detector measures applied pressure and modulates the resonance frequency or amplitude of the resonance circuit accordingly. This merging combines the pressure sensing function with the existing communication infrastructure, achieving precise pressure detection without proportionally increasing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The resonance circuit serves multiple functions: it acts as both the communication transmitter and the pressure-sensitive sensor. When pressure is applied to the pen tip, it directly affects the resonance characteristics of the circuit, which are then transmitted to the interface device. This multi-functional design enables pressure detection without requiring a completely separate sensing system.

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

4Measurement precision

If an interface device includes digitizer for generating external magnetic field, then electronic pen detection accuracy is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvepen detection accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of requiring the interface device to actively generate magnetic fields for detection, the invention inverts the approach by enabling the electronic pen to generate its own magnetic field through the signal generator and resonance circuit. The interface device then detects these actively generated fields from the pen, improving detection accuracy without requiring complex digitizer infrastructure in the interface device.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The electronic pen becomes self-sufficient by generating its own magnetic field signals through the integrated signal generator and resonance circuit. This self-service capability eliminates the dependency on the interface device to provide external magnetic fields, allowing the pen to operate accurately with or without a digitizer in the interface device, thereby reducing the complexity requirements for the interface device.

Inventive Principle:
Principle #25Self-service

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 efficient and flexible input methods for multimedia devices, allowing for precise control and data transmission, including tilt, pressure, and button information, without the need for a digitizer in the device, enhancing user interaction and battery efficiency.

Implementation Method 1

a resonance circuit configured to be charged by a current based on the AC signal during a section in which the enable signal is activated, and configured to be discharged and emit a magnetic field during an output section in which the enable signal is inactivated

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a pressure detector electrically connected to the resonance circuit and configured to detect a physical pressure applied to the pen tip

Methodology Applied
Scientific EffectPressure detection:

Implementation Method 3

a signal detector for detecting an external magnetic field provided from the outside of the electronic pen and controlling the transmission of the AC signal according to whether the external magnetic field is detected

Methodology Applied
Scientific EffectMagnetic field detection:

Data Source

PatentEP4047459B1Electronic pen and interface device including the same
Publication Date: 2024.04.03 SAMSUNG DISPLAY CO LTD
  • EP4047459B1 patent drawingFigure 1A
  • EP4047459B1 patent drawingFigure 1B
  • EP4047459B1 patent drawingFigure 2

AI summary

An electronic pen (PN) includes a signal generator (PN200, PN401), a power supply (PN300, PN501), and a resonance circuit (PN100, PN101). The signal generator is configured to generate a signal. The power supply (PN300, PN501) is configured to supply power to the signal generator. The resonance circuit (PN100, PN101) is configured to generate a current based on the signal and emit a magnetic field based on the current.