Low Power Touch Sensing During Sleep State

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Solution Overview

Problem

Existing touch sensor panels in electronic devices are unable to efficiently sense touch inputs during a sleep state while minimizing power consumption, limiting their ability to respond to touch events without fully awakening the device.

Innovation Solution

Implementing a touch sensing system that utilizes self-capacitance and mutual capacitance techniques, where the touch screen can detect touch inputs by measuring changes in capacitance through a matrix of conductive plates and integrated touch sensing circuitry, even when the device is in a low-power sleep state, allowing for selective wake-up based on specific touch events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electronic device performs touch sensing during sleep state, then the ability to detect touch inputs is improved, but power consumption increases

Engineering Contradiction:

Improvetouch detection capabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The touch sensing system performs periodic scanning at reduced frequency during sleep state compared to awake state. The controller alternates between active touch sensing during awake periods and periodic, lower-frequency scanning during sleep periods, enabling touch detection while minimizing power consumption through intermittent operation

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

During sleep state, the system performs only essential touch sensing operations rather than full touch processing. The sensing continues at a reduced level to detect wake-triggering gestures, but full touch processing and display updates are suspended until wake is detected, performing just enough action to maintain core functionality

Inventive Principle:

Principle #16Partial or excessive action

2Ease of operation

If the electronic device remains in awake state to detect touch inputs, then touch response capability is maintained, but power consumption increases

Engineering Contradiction:

Improvetouch response capabilityVSAvoidpower consumption

Core Design Contradiction:

Ease of operationVSUse of energy by stationary object

Solution Approach 1:

The system transitions from continuous touch sensing in awake state to periodic, lower-frequency scanning in sleep state. This allows the device to maintain touch detection capability while operating at reduced power levels during sleep, only fully activating touch processing when needed

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The touch sensing system dynamically adjusts its operational state based on device state. During sleep, the sensing operates in a low-power mode with reduced scanning frequency, and automatically transitions to full operational mode when touch wake is detected, providing adaptive power management

Inventive Principle:

Principle #15Dynamics

3Loss of energy

If the electronic device enters sleep state to reduce power consumption, then power efficiency is improved, but the ability to respond to touch inputs is reduced

Engineering Contradiction:

Improvepower efficiencyVSAvoidtouch input response

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The system implements periodic touch scanning during sleep state that is sufficient to detect wake-triggering gestures. This periodic scanning maintains basic touch detection reliability while operating at reduced power levels, balancing energy efficiency with functional responsiveness

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The touch sensing system during sleep state is designed to autonomously detect wake-triggering gestures and initiate device wake without requiring full system activation. The periodic scanning automatically identifies touch events that should trigger wake, enabling the system to serve itself by detecting when full operational mode should resume

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 the electronic device to detect touch inputs during sleep state with reduced power consumption, allowing for efficient wake-up upon specific touch events, such as taps, while maintaining low power usage.

Implementation Method 1

measuring changes in capacitance through a matrix of conductive plates

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

fringing electrical fields used to detect touch can extend beyond the surface of the display

Methodology Applied

Scientific EffectElectrical field: Electric Field

Data Source

PatentUS11614788B2Low power touch sensing during a sleep state of an electronic device

Publication Date: 2023.03.28 APPLE INC

AI summary

An electronic device is disclosed. The electronic device can sense touch on its touch screen while in a sleep state in a manner that allows the electronic device to respond to certain touch inputs, while consuming less power due to touch sensing than while in an awake state. For example, sensing touch during the sleep state can allow the electronic device to wake (e.g., transition from the sleep state to the awake state) in response to detecting a certain touch input (e.g., a tap or other touch input) on its touch screen while in the sleep state. Various ways for the electronic device to sense touch during the sleep state are disclosed.