Directional Capacitive Sensing for Longer-Range Proximity Detection
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Solution Overview
Problem
Existing capacitive sensor technologies for detecting object proximity, such as touch pads, are limited in detecting objects at distances greater than a few millimeters and lack effective directivity and high detection distance capabilities.
Innovation Solution
A capacitive sensor device with electrodes formed on an electrically insulating medium deposited on a conductive shield, featuring a control circuit that simultaneously activates all electrodes to measure capacitance, and includes an electrically conductive edge and insulating layer to enhance detection field directivity and range, allowing for detection of objects several centimeters away.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional touch pad electrodes are used, then object detection is possible, but detection distance is limited to a few millimeters
Solution Approach 1:
The patent transitions from a two-dimensional touch pad surface to a three-dimensional detection volume by using multiple electrodes at different heights (first electrodes on front surface, second electrodes on rear surface) to create a volumetric detection field that extends several centimeters from the device surface
Solution Approach 2:
The patent embeds multiple electrode systems within the device thickness - first electrodes are formed on the front surface while second electrodes are formed on the rear surface, nesting detection capabilities within the device body to achieve extended range without increasing footprint
2Ease of operation
If conventional touch pad electrodes are used, then object presence can be detected, but directivity is poor
Solution Approach 1:
The patent divides the detection system into functionally distinct first electrodes and second electrodes positioned at opposite surfaces, with each electrode type contributing to different aspects of the detection field, enabling directional control through selective activation and measurement combinations
Solution Approach 2:
The patent creates an asymmetric electrode arrangement where first electrodes and second electrodes have different spatial positions and orientations relative to the device surfaces, allowing the detection field to be shaped with preferred directions rather than uniform omnidirectional response
3Adaptability or versatility
If capacitance measurement circuitry is added to detect proximity, then object detection capability is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing touch pad electrode structure serve dual functions - maintaining its original touch detection capability while simultaneously functioning as a proximity sensor through the same capacitance measurement circuitry, eliminating the need for separate dedicated proximity detection hardware
Solution Approach 2:
The patent enables the touch pad's own electrode structure to provide proximity detection functionality without requiring external or additional specialized components, using the inherent capacitance properties of the existing electrodes for both touch and proximity sensing applications
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 solution enables accurate detection of objects at greater distances with improved directivity and range, effectively activating or deactivating system functions based on user proximity, such as keyboard backlighting or screen energy modes.
Implementation Method 1
capacitive sensor-type device for detecting the proximity of an object
Implementation Method 2
electrodes formed on an electrically insulating medium deposited on a conductive shield
Data Source
AI summary
The present disclosure relates to a method for detecting an object near an electronic system, comprising steps of: forming electrodes around a central area, on an electrically insulating medium, determining measurements representative of the capacitance of the electrodes, and comparing the measurements with a detection threshold, and deducing whether or not an object is near the central area in a detection, the electrically insulating medium on which the electrodes are formed being deposited on an electrically conductive medium forming a shield, the capacitance measurements being taken by simultaneously activating all the electrodes.