Pyroelectric Push Gesture Sensing for Low-Power Switch Actuation
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Solution Overview
Problem
Existing gesture recognition systems for mobile devices face challenges in miniaturization, cost-effectiveness, and energy efficiency, particularly when recognizing non-tactile gestures, as camera-based systems consume high energy and occupy large space, while alternative solutions like high-speed spectrometers are costly and unsuitable for miniaturized designs.
Innovation Solution
A switch actuation device utilizing a gesture sensor with pyroelectric material, such as lead zirconate titanate, to detect non-tactile 'push' gestures through heat emission, featuring an approach, waiting, and retraction phase, with a signal evaluation unit controlling an actuator to activate switches safely and with low energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If camera-based devices are used for gesture recognition, then gesture recognition capability is achieved, but device size increases and costs rise
Solution Approach 1:
The patent replaces camera-based optical detection with a pyroelectric sensor array that detects thermal radiation from gestures. This substitution of detection mechanism enables gesture recognition without requiring large camera modules, thus reducing device size while maintaining recognition capability
Solution Approach 2:
The patent changes the detection parameter from optical (camera-based) to thermal (pyroelectric sensor-based). This parameter change allows for a more compact sensor design since pyroelectric sensors can be miniaturized more effectively than camera systems, resolving the contradiction between recognition capability and device size
2Reliability
If camera-based devices are used for gesture recognition, then gesture recognition capability is achieved, but energy consumption increases
Solution Approach 1:
The patent replaces continuous operation camera systems with pyroelectric sensors that detect thermal changes. Pyroelectric sensors consume significantly less energy as they only require minimal power for signal processing, thereby reducing overall energy consumption while maintaining gesture recognition functionality
Solution Approach 2:
The patent utilizes the periodic nature of thermal radiation detection from moving gestures. The pyroelectric sensors detect thermal changes only when gestures occur, rather than requiring continuous high-power operation, thus reducing average energy consumption while maintaining recognition capability
3Measurement precision
If high-speed spectrometers are used for gesture detection, then detection precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive high-speed spectrometers with relatively inexpensive pyroelectric sensors. While individual sensors are simpler and less precise than spectrometers, the array configuration maintains adequate detection precision while dramatically reducing manufacturing costs and enabling mass production
Solution Approach 2:
The patent uses an array of multiple pyroelectric sensors to replicate detection functionality across multiple detection points. This copying approach with simpler sensors achieves comparable overall system precision to a single complex spectrometer while being more cost-effective and manufacturable
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, error-free, and energy-efficient recognition of non-tactile gestures in a miniaturized design, suitable for mobile devices, with low production costs and reduced interference from environmental signals.
Implementation Method 1
the gesture sensor being set up to detect heat emitted by the part when the gesture is performed by means of at least one pixel having a thin film made of pyroelectric material and per Pixel to output a signal with signal deflections corresponding to the intensity curve over time of the heat detected by the pixel
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A switch actuation system (100) comprising: a gesture sensor (1) for actuating a switch (103) using a non-tactile push gesture (115) which is to be executed with a heat-emitting part (114) and is composed of an approach phase (111) in which the part (114) approaches the gesture sensor (1), a waiting phase (113) in which the part (114) remains in the vicinity of the gesture sensor, (1) and a retreat phase (112) in which the part (114) moves away from the gesture sensor (1), the gesture sensor (1) being configured to detect heat emitted by the part (114) during execution of the gesture (115), using at least one pixel (21 to 24) containing a thin film of pyroelectric material, and for each pixel (21 to 24) to emit a signal (51 to 54) with signal excursions (56, 57) that correspond to the temporal variation in the intensity of the heat detected by the pixels (21 to 24); a signal analysis unit (101) by means of which the execution of the gesture (115) can be determined from the temporal sequence of signal excursions (56, 57); and an actuator (104) which is controlled by the signal analysis unit (101) and actuates the switch (103) when the execution of the gesture (115) is detected.