Position Pointer Signal Supply Control for Hovering Detection

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Solution Overview

Problem

Existing active capacitive pens lack the ability to detect inclination angles and hovering distances effectively, with existing technologies failing to simultaneously improve hovering performance and reduce power consumption.

Innovation Solution

A position pointer with a signal supply controlling circuit that selectively supplies signals of different levels to electrodes, allowing for enhanced detection of inclination angles and hovering states while minimizing power consumption by adjusting signal levels based on the pointer's position relative to the sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a high signal level is continuously supplied to electrodes to improve hovering detection sensitivity, then the detection precision of hovering distance is improved, but the power consumption increases

Engineering Contradiction:
Improvehovering distance detection sensitivityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic switching between first and second signal levels rather than continuous high-level signal supply. The signal supply control circuit alternates between the first signal level (higher power, better detection) and second signal level (lower power), enabling the system to maintain detection sensitivity while reducing average power consumption through time-based modulation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent dynamically adjusts the signal level based on detected hovering distance. When the position pointer is close to the sensor (small hovering distance), the first signal level is supplied to maintain high detection sensitivity. When the hovering distance increases, the signal level switches to the second level to conserve power, creating a dynamic adaptation to operational conditions.

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If the signal level is reduced to minimize power consumption, then the power consumption is reduced, but the detection sensitivity of hovering distance and inclination angle deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoiddetection sensitivity
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The system periodically supplies the first signal level at predetermined intervals even when operating at the second signal level. This periodic high-level signal injection maintains detection sensitivity for hovering distance and inclination angle without requiring continuous high power consumption, allowing the system to balance power savings with measurement capability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent performs preliminary detection using the second signal level to assess hovering distance. Based on this preliminary assessment, it determines whether switching to the first signal level is necessary for accurate measurement, enabling the system to maintain low power consumption while being ready to enhance sensitivity when needed.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If multiple electrodes are activated simultaneously to improve angle detection accuracy, then the measurement precision of inclination angle is improved, but the device complexity increases

Engineering Contradiction:
Improveinclination angle detection accuracyVSAvoidsignal supply control complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the electrode activation into distinct time periods - a first period for hovering distance detection and a second period for inclination angle detection. Different electrodes are activated in different segments of the detection cycle, allowing accurate angle measurement through multiple electrode interactions without requiring all electrodes to be simultaneously active, thus managing complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The signal supply control circuit uses periodic timing to activate different electrodes in different cycles. By alternating which electrodes receive signals during different periods, the system achieves comprehensive angle detection capability while maintaining a relatively simple control structure that manages electrode activation through time-based segmentation rather than complex simultaneous control.

Inventive Principle:
Principle #19Periodic action

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 high-sensitivity detection of hovering distances and inclination angles, extending the battery life of the active capacitive pen by optimizing signal strength and power usage.

Implementation Method 1

The position detection apparatus detects a position pointed to by an active capacitive pen by receiving, at the first conductors of the first direction and the second conductors of the second direction of the sensor thereof, signals from the active capacitive pen through capacitive coupling

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP3059665B1Position pointer, signal processing circuit, signal supply controlling method and signal processing method
Publication Date: 2020.09.16 WACOM CO LTD
  • EP3059665B1 patent drawingFigure 1
  • EP3059665B1 patent drawingFigure 2A~2B
  • EP3059665B1 patent drawingFigure 3

AI summary

A position pointer includes a first electrode disposed so as to project from one end portion of a pen-shaped housing in an axial direction; a second electrode disposed in a proximity of the first electrode so as to surround a center axis of the pen-shaped housing; and a signal generation circuit which, in operation, generates a given signal. The signal generated by the signal generation circuit is outputted to a sensor provided in a position detection apparatus. The signal generation circuit, in operation, generates a signal of a first signal level and a signal of a second signal level lower than the first signal level. A signal supply controlling circuit, in operation, selectively supplies the signal of the first signal level and the signal of the second signal level generated by the signal generation circuit to the second electrode.