Active Stylus Power Management via Wireless Energy Allocation

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Solution Overview

Problem

Current touch-sensitive systems, particularly capacitive touch screens, face challenges in accurately detecting the presence and location of objects, especially when multiple objects are in close proximity or when the touch is light, leading to interference and reduced accuracy.

Innovation Solution

The implementation of an active stylus with a capacitive touch sensor system that includes a touch-sensor controller, drive electrodes, and sense electrodes, which use capacitive coupling to detect changes in capacitance, allowing for precise detection of object proximity and location, and a power management system for efficient energy allocation between the stylus and the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If capacitive touch sensor is used to detect object proximity, then touch detection capability is enabled, but detection accuracy deteriorates when multiple objects are in close proximity or when touch is light

Engineering Contradiction:

Improvetouch detection capabilityVSAvoiddetection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The touch-sensitive display is divided into multiple segments including a first touch-sensitive area, a second touch-sensitive area, and a third touch-sensitive area. Each area can independently detect touch inputs, allowing the system to distinguish between multiple objects by analyzing which segments are activated and the pattern of activation across segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A processor acts as an intermediary that receives signals from multiple touch-sensitive areas and object identifiers from the active stylus. The processor analyzes these intermediate signals to determine the identity and location of objects, resolving the ambiguity that arises when multiple objects are in close proximity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If active stylus with internal power source is implemented, then functionality is enhanced, but energy consumption increases

Engineering Contradiction:

Improvestylus functionalityVSAvoidenergy consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The system implements periodic wireless charging by establishing a magnetic coupling between the portable device and the active stylus at predetermined intervals. This allows the power source in the stylus to be recharged periodically while maintaining normal operation, thereby extending functionality without proportionally increasing continuous energy consumption.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The active stylus is equipped with an internal power source that enables it to function independently without requiring constant external power supply. The stylus serves itself by containing its own power source and being capable of recharging through wireless power transfer when in proximity to a portable device.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If wireless power transfer is implemented between device and stylus, then energy allocation flexibility is improved, but system complexity increases

Engineering Contradiction:

Improveenergy allocation flexibilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system replaces mechanical or wired power transfer mechanisms with wireless electromagnetic power transfer. A transmitter in the portable device and a receiver in the active stylus enable contactless power transfer through electromagnetic fields, eliminating the need for physical connections and reducing mechanical complexity while improving energy allocation flexibility.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The wireless power transfer system serves multiple functions: it charges the stylus power source, monitors power levels, and enables bidirectional energy management between the device and stylus. This multi-functional approach consolidates several operations into a single system, managing complexity through versatility rather than adding separate dedicated systems.

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

Enhances the accuracy and reliability of touch detection, enabling precise interaction with touch-sensitive devices by minimizing interference and optimizing energy usage, thereby improving user experience and device functionality.

Implementation Method 1

a touch-sensor controller, drive electrodes, and sense electrodes, which use capacitive coupling to detect changes in capacitance

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

Power management systems and power sources may allocate to one or more components electric energy existing on or incoming to one or more components

Methodology Applied

Scientific EffectElectromagnetic energy transfer: Electromagnetic Induction

Data Source

PatentUS9874920B2Power management system for active stylus

Publication Date: 2018.01.23 WACOM CO LTD

AI summary

In one embodiment, a stylus includes one or more electrodes and one or more computer-readable non-transitory storage media embodying logic for transmitting signals wirelessly to a device through a touch sensor of the device. The computer-readable non-transitory storage media of the stylus further embodies logic for allocating between the stylus and the device electric energy available at the stylus or the device based on one or more first criteria.