Active Stylus State Circuit Time Constant Management

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Solution Overview

Problem

Existing touchscreens have limitations in spatial resolution and functionality when using passive styluses, which restrict fine line drawing and detail selection, and lack features like pressure sensing.

Innovation Solution

An active stylus with a battery and energy-conservative controller that transitions between dormant and active states based on user input, utilizing a POPAT circuit and state circuit with adjustable time constants to optimize battery usage and enable enhanced functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an active stylus operates continuously in active state to provide fine spatial resolution and pressure sensing, then functionality and measurement precision are improved, but battery energy consumption increases

Engineering Contradiction:

Improvespatial resolutionVSAvoidbattery energy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The stylus dynamically transitions between dormant and active states based on user interaction detection. The POPAT circuit periodically tests for user presence, and when detected, the stylus transitions to active state with enhanced functionality. This dynamic state management allows the stylus to maintain measurement precision when needed while minimizing energy consumption during non-use periods.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The POPAT (Popup and Test) circuit implements periodic action by repeatedly testing for user presence at predetermined intervals while the stylus is in dormant state. This periodic testing mechanism allows the stylus to remain in low-power dormant state while still being able to quickly transition to active state when user interaction is detected, thus balancing energy efficiency with functionality.

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If the stylus remains in dormant state to conserve battery energy, then energy consumption is reduced, but responsiveness to user input is delayed

Engineering Contradiction:

Improvebattery energy consumptionVSAvoidresponsiveness

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The POPAT circuit performs preliminary actions by periodically testing for user presence even while the stylus is in dormant state. This preliminary detection mechanism ensures that when a user does interact with the stylus, the system is already aware of their presence and can quickly transition to active state, minimizing response delay while maintaining energy efficiency during non-use periods.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If the stylus operates in active state with enhanced functionality, then pressure sensing and fine line drawing are enabled, but device complexity increases

Engineering Contradiction:

ImprovefunctionalityVSAvoidcontroller complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The controller is designed to perform multiple functions depending on the operational state. In dormant state, it performs minimal population and testing functions. In active state, it enables pressure sensing, fine line drawing, and other enhanced functionalities. This multi-functionality approach allows a single controller to handle both simple and complex operations, reducing the need for separate dedicated circuits for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10474258B2Active stylus

Publication Date: 2019.11.12 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Apparatus for determining user operation of an actuator, based on determining a time constant of a state circuit coupled to the actuator.