Capacitive Position Indicator Tilt Detection Circuit

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Solution Overview

Problem

The existing capacitive position indicator systems face high capacitance and current consumption issues due to the direct supply of signals to multiple electrodes, which hinders accurate tilt angle detection and increases power consumption.

Innovation Solution

A position indicator with a pen-shaped chassis, a first electrode, and a second electrode that surrounds the first electrode, featuring a signal sending control circuit to manage capacitive interaction with the sensor, allowing for controlled detection regions and reduced current consumption by switching the signal supply through an inductance circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If signals are directly supplied to multiple electrodes (first electrode and second electrode) for position and tilt detection, then detection accuracy is improved, but capacitance and current consumption increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidcurrent consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by alternately supplying signals to the first electrode and second electrode in time-division multiplexing manner. The signal supply is performed in periodic cycles where one electrode is activated at a time, rather than continuously activating all electrodes. This periodic switching enables both position and tilt detection while significantly reducing current consumption compared to simultaneous multi-electrode activation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent employs dynamics by making the electrode configuration adaptive and switchable. The system dynamically switches between different electrode activation states based on detection requirements. The signal sending control circuit dynamically adjusts which electrode receives the signal at any given moment, enabling flexible detection modes that optimize both accuracy and power consumption.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If signals are supplied to multiple electrodes simultaneously for comprehensive detection, then detection capability is improved, but capacitance increases

Engineering Contradiction:
Improvedetection capabilityVSAvoidcapacitance
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent uses periodic action to activate electrodes in alternating time slots rather than simultaneously. The signal sending control circuit implements periodic switching between the first electrode and second electrode, ensuring that at any moment only one electrode is active. This approach maintains comprehensive detection capability while keeping the total capacitance load low, as capacitive elements are not all charged simultaneously.

Inventive Principle:
Principle #19Periodic action

3Use of energy by moving object

If the signal supply is switched using a switching circuit, then power consumption is reduced, but circuit complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidcircuit complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The signal sending control circuit is designed with multi-functionality to perform multiple tasks: it generates detection signals, switches between different electrodes, controls signal timing, and manages power distribution. By consolidating these functions into a single control circuit, the patent reduces the need for separate dedicated circuits for each function, thereby limiting the increase in overall circuit complexity while achieving power consumption reduction through selective electrode activation.

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

This configuration enables efficient detection of the position and tilt angle with reduced power consumption, allowing for accurate positioning and tilt detection without the need for correction based on detected tilt angles.

Implementation Method 1

a signal from this signal generating circuit is transmitted to a sensor of a position detecting device through an electrically-capacitive core body based on capacitive coupling

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

switching the signal supply through an inductance circuit

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3702890B1Position indicator and associated method and system
Publication Date: 2023.03.15 WACOM CO LTD
  • EP3702890B1 patent drawingFigure 1
  • EP3702890B1 patent drawingFigure 2
  • EP3702890B1 patent drawingFigure 3

AI summary

The tilt of a position indicator can be detected with low current consumption. There is provided a position indicator that has a pen-shaped chassis and includes a first electrode and a second electrode disposed on the side of one end of the chassis and a signal generating circuit that generates a signal supplied to at least the first electrode and carries out capacitive interaction with a sensor of a position detecting device. The second electrode is disposed to surround the first electrode in such a manner that the first electrode is partly exposed in the axis-center direction of the chassis and the second electrode is composed of at least one electrode. The position indicator includes a signal sending control circuit that is coupled to the second electrode and controls the second electrode to give change to the capacitive interaction between the first electrode and the sensor formed through supply of a signal from the signal generating circuit to the first electrode.