Three-Electrode Capacitive Sensor Module for Proximity and Tactility
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Solution Overview
Problem
Capacitive measuring systems for detecting object approach and contact lack functional safety, often resulting in uninterpretable signals due to electrode failure or damage, requiring redundant verification and additional electrodes for testing.
Innovation Solution
A sensor module with a three-electrode configuration that allows for self-capacitive and double-sided capacitive modes, enabling simultaneous detection of proximity and tactility events without additional electrodes, by using a central sensor element for active shielding and a passive test circuit to check for electrode functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional electrodes are added for testing functionality, then functional safety is improved, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by enabling the existing three sensor elements to serve multiple purposes: proximity detection, tactility detection, and functionality testing. The controller dynamically configures the electrode connections to implement different measurement configurations (self-capacitive, double-sided capacitive, and test configurations) without requiring additional dedicated test electrodes, thus achieving functional safety while maintaining structural simplicity
Solution Approach 2:
The patent merges the testing function with the existing sensor elements by using the same three electrodes for both measurement and self-testing. The test configuration utilizes the existing electrode connections and controller resources to monitor electrode functionality, integrating the safety testing capability into the original sensor structure rather than adding separate testing components
2Reliability
If additional electrodes are added for testing, then functionality testing capability is improved, but manufacturing cost increases
Solution Approach 1:
The sensor module is designed with multi-functional sensor elements that can operate in different configurations (proximity detection, tactility detection, and functionality testing) using the same three electrodes. This eliminates the need for additional dedicated test electrodes, reducing manufacturing complexity and cost while maintaining comprehensive testing capability
Solution Approach 2:
The sensor module performs self-testing of electrode functionality using its own existing electrodes and controller resources. The test configuration enables the sensor elements to monitor their own operational status without requiring external testing equipment or additional test electrodes,实现ing cost-effective self-diagnosis
3Reliability
If measurement signal is modulated for testing, then functionality monitoring is improved, but measurement precision deteriorates
Solution Approach 1:
The controller implements periodic switching between different measurement configurations (self-capacitive, double-sided capacitive, and test configurations) to monitor electrode functionality. This time-multiplexed approach allows functionality testing without continuous signal modulation, maintaining measurement precision during normal operation while enabling periodic safety monitoring
Solution Approach 2:
The test configuration enables preliminary detection of electrode failures before they affect normal measurement operations. By monitoring electrode functionality in advance through the test configuration, the system can identify and flag potential issues before they compromise measurement accuracy in the primary measurement modes
4Reliability
If redundant verification is implemented, then functional safety is improved, but processing time increases
Solution Approach 1:
The patent combines multiple measurement functions (proximity detection, tactility detection, and functionality testing) into a single integrated sensor module with three sensor elements. The controller simultaneously manages multiple measurement configurations without requiring separate redundant verification systems, reducing processing time while maintaining functional safety through integrated self-monitoring
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
This configuration enhances functional safety by allowing synchronous recording of proximity and tactility events and functionality testing without additional electrodes, ensuring reliable detection of object approach and contact without time gaps or interruptions.
Implementation Method 1
capacitive sensor module...capacitively detect the approach of an object...capacitively detect tactile events
Implementation Method 2
capacitive measuring systems used to detect the approach of objects...electrical potential can be applied to each of the sensor elements
Data Source
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AI summary
The invention relates to a sensor module (100) for capacitively detecting the approach of an object (1) to the sensor module (100) and for capacitively detecting tactile events between an object (1) and the sensor module (100), comprising: at least three sensor elements (13, 8a, 8b), the sensor elements (13, 8a, 8b) being at least partially electrically conductive and arranged one above the other and spaced apart from one another in such a way that a sensor element stack arrangement is formed and an electric potential can be applied to each of the sensor elements (13, 8a, 8b) and the sensor elements are electrically insulated from one another, and the sensor element stack arrangement having at least a first and a second outer sensor element (13, 8b) and at least one central sensor element (8a) arranged between the two outer sensor elements; at least one compressible layer (10), which is arranged between two of the sensor elements (8a, 8b); characterised in that the sensor module (100) is designed in such a way that it can be operated with three different measuring configurations and at least one test configuration which is capacitive on both sides, the measuring configurations comprising: a self-capacitive approach configuration, an approach configuration which is capacitive on both sides, and a tactility configuration which is capacitive on both sides, and it being possible to operate simultaneously the approach configuration and the tactility configuration which is capacitive on both sides.