Fringe-Field Capacitive Sensor Layout for Compact Air Gesture Detection
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Solution Overview
Problem
Existing gesture recognition systems, such as those using electromagnetic waves and machine vision, require large space and high energy consumption due to the need for dedicated sensors and complex signal processing, making them inefficient for compact devices.
Innovation Solution
A capacitive sensor utilizing fringe field effect with a specific ratio of plate length to spacing, made of conductive materials, detects air gestures with a small size and low energy consumption, enabling efficient gesture recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic wave-based gesture recognition (radar, millimeter wave) is used, then gesture detection capability is achieved, but device size and energy consumption increase due to dedicated sensor chips and complex signal processing
Solution Approach 1:
The patent replaces electromagnetic wave-based radar systems with a capacitive sensing system that uses electrical field effects. Instead of using dedicated radar sensor chips and complex signal processing circuits, the invention employs simple capacitive electrodes that detect gestures through changes in capacitance caused by proximity of conductive objects (fingers). This substitution dramatically reduces device size while maintaining gesture detection functionality.
Solution Approach 2:
The patent uses the electrical field pattern (fringe field) created by capacitive electrodes as a simplified model for gesture detection, replacing the need for complex electromagnetic wave transmission and reception systems. The capacitive field acts as a proxy for the more complex radar electromagnetic fields, achieving similar detection purposes with much simpler hardware.
2Reliability
If electromagnetic wave-based gesture recognition system is implemented, then gesture recognition function is provided, but energy consumption increases due to continuous operation of sensor and signal processing circuit
Solution Approach 1:
The capacitive sensing system operates by periodically sampling capacitance values at different electrode positions rather than continuously processing electromagnetic signals. This periodic sampling approach significantly reduces energy consumption while still providing reliable gesture recognition functionality.
Solution Approach 2:
The patent employs simple capacitive electrodes with basic readout circuitry instead of expensive, power-hungry radar sensor chips and complex signal processing units. The simplified hardware architecture consumes much less energy while achieving the same gesture detection purpose.
3Measurement precision
If dedicated radar sensor chip is used for gesture recognition, then accurate gesture detection is achieved, but occupied space increases
Solution Approach 1:
The patent divides the gesture detection function into multiple distributed capacitive electrodes arranged in arrays across the device surface. Instead of using a single dedicated radar sensor chip, multiple simple capacitive sensing elements work together to provide accurate gesture detection across different zones, reducing the space required for each individual sensing element.
Solution Approach 2:
The capacitive electrode arrays serve multiple functions: they detect gestures, determine position, and identify gesture types, replacing the need for specialized radar sensor hardware. This multi-functional approach achieves accurate gesture detection while minimizing occupied space.
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
The capacitive sensor effectively detects air gestures with reduced space and energy usage, enhancing the usability of electronic devices by allowing compact integration and lower power consumption.
Implementation Method 1
The capacitive sensor includes M plate pairs. In the M plate pairs, each plate pair includes a first plate and a second plate that are placed opposite to each other. In each plate pair, a ratio of a plate length of each plate pair to a spacing in each plate pair is greater than 1 and less than or equal to 30.
Data Source
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AI summary
A capacitive sensor, an electronic device, and an electronic device control method are disclosed, and relate to the field of sensor technologies. The capacitive sensor includes at least one plate pair. Each plate pair includes a first plate and a second plate that are placed opposite to each other. A ratio of a plate length of each plate pair to a spacing in the plate pair is greater than 1 and less than or equal to 30. The capacitive sensor can detect an air gesture of a user based on fringe field effect, and has advantages of a small size and low energy consumption.