Pyroelectric Gesture Switch Actuation for Low-Power Mobile Devices

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Solution Overview

Problem

Existing non-tactile gesture recognition systems for mobile devices are hindered by large size, high costs, and high energy consumption, making them unsuitable for miniaturized designs, and conventional touch screens only recognize tactile gestures.

Innovation Solution

A switch actuation device using a gesture sensor with four pixels made of pyroelectric material to detect heat emitted by a hand, a signal evaluation unit to identify specific non-tactile gestures, and an actuator to activate switches based on these gestures, allowing for reliable and error-free operation with low energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a camera is used to capture non-tactile gestures, then gesture recognition capability is achieved, but device size and cost increase significantly

Engineering Contradiction:
Improvegesture recognition capabilityVSAvoiddevice size
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent replaces the optical camera-based gesture recognition system with a capacitive sensor system that detects gestures through electrical field interactions. This substitution eliminates the need for bulky camera hardware while maintaining gesture recognition functionality, directly resolving the contradiction between gesture recognition capability and device size.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from optical signals (camera-based) to electrical field/capacitive signals. By measuring changes in capacitance caused by hand proximity and gestures, the system achieves gesture recognition without requiring the large physical dimensions of a camera, thus reducing device size while preserving adaptability.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a camera is used to capture non-tactile gestures, then gesture recognition capability is achieved, but investment costs increase

Engineering Contradiction:
Improvegesture recognition capabilityVSAvoidinvestment costs
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive camera hardware with cost-effective capacitive sensors that are already integrated into mobile devices. This substitution significantly reduces investment costs while maintaining gesture recognition capability, as capacitive sensors are standard components in modern smartphones.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent leverages the existing capacitive touchscreen infrastructure of mobile devices for additional gesture recognition functionality. By using the same sensor array that serves as the touchscreen interface, the system achieves gesture recognition without requiring separate dedicated hardware, thereby reducing manufacturing costs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If high-speed spectrometers are used to detect gestures, then detection precision is improved, but miniaturization becomes difficult

Engineering Contradiction:
Improvegesture detection precisionVSAvoiddevice size
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent replaces high-speed spectrometers with capacitive sensors that detect gestures through electrical field interactions. This substitution maintains sufficient detection precision for gesture recognition while enabling miniaturization, as capacitive sensors can be fabricated in standard semiconductor processes with minimal physical footprint.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If camera-based gesture recognition is implemented, then non-tactile gesture detection is achieved, but energy consumption increases

Engineering Contradiction:
Improvenon-tactile gesture detectionVSAvoidenergy consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces energy-intensive camera-based gesture recognition with low-power capacitive sensing. Capacitive sensors consume minimal energy as they operate by detecting changes in electrical fields without requiring active illumination or complex image processing, thus reducing energy consumption while maintaining non-tactile gesture detection capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

5Use of energy by moving object

If four pixels with pyroelectric material are used to detect heat, then energy consumption is reduced, but gesture recognition reliability must be maintained

Engineering Contradiction:
Improveenergy consumptionVSAvoidgesture recognition reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent uses pyroelectric pixels that detect thermal radiation from the hand instead of capacitive sensors. This substitution reduces energy consumption as pyroelectric detection is passive and requires minimal power, while the thermal signature of the hand provides reliable gesture information through the approach, wait, and translation phases.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent incorporates a waiting phase in the gesture sequence where the hand remains stationary near the sensor before executing the gesture. This preliminary action allows the pyroelectric sensor to stabilize and accurately detect the thermal signature, ensuring reliable gesture recognition despite the low-power passive detection method.

Inventive Principle:
Principle #10Preliminary 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

Enables reliable recognition of non-tactile gestures with low energy consumption and cost-effective miniaturization, suitable for mobile devices, allowing for safe and error-free switch actuation.

Implementation Method 1

each have a thin film of pyroelectric material, with a signal deflection corresponding to the temporal intensity profile of the heat detected by the thin film of the corresponding pixel

Methodology Applied
Scientific EffectPyroelectric effect: Pyroelectric Effect

Data Source

PatentEP3224955B1Switch actuating device, mobile device, and method for actuating a switch by means of a non-tactile gesture
Publication Date: 2020.02.26 PERLOS OY
  • EP3224955B1 patent drawingFigure 1~3
  • EP3224955B1 patent drawingFigure 4~5
  • EP3224955B1 patent drawingFigure 6~7

AI summary

The invention relates to a method for operating a switch actuating device (11), having the following steps: outputting the pixels of the signal excursions (49, 79) caused in the approach phase (3) and the signal excursions (50, 80) caused in the translation phase to a signal analyzing unit, wherein the non-tactile gestures are performed using the heat-emitting part, and a waiting level which has a lower value than the values of the extreme values of the signal excursions is reached between the signal excursions during the waiting phase (4) of the signal; monitoring the signal and identifying the occurrence of a sequence of the signal excursions and the signal waiting level lying chronologically between the signal excursions; proceeding with the next step as soon as the sequence has been identified; checking whether the signal excursions caused in the approach phase have a direction opposite the signal excursions caused in the translation phase; proceeding with the next step if the check is positive; checking whether the time offset of the signal excursions caused in the approach phase lie within a first specified span of time; proceeding with the next step if the check is positive; and checking whether the time offset of the chronologically first and the chronologically last signal excursion caused in the translation phase lies within two thresholds, the lower threshold of which is larger than null.