Capacitive Proximity Sensor With Collision Threshold Detection
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Solution Overview
Problem
Current proximity detection systems in medical imaging systems, such as ultrasound and capacitive sensors, fail to provide adequate collision detection in safety-critical environments like operating theaters, as they can be influenced by liquids and do not meet the required safety standards for immediate error recognition, leading to potential injuries from collisions during device movement.
Innovation Solution
A capacitive sensor apparatus with a compressible insulator layer and dual conductor track arrangements, capable of distinguishing between proximity and collision thresholds, using a flexible design to enhance sensitivity and robustness, and incorporating temperature compensation and self-supervision features to prevent false readings and ensure reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive sensors are used for proximity detection, then proximity can be detected, but measurement precision deteriorates when liquids are present on the device surface
Solution Approach 1:
The sensor system is segmented into two independent sensor types: capacitive sensors for proximity detection and contact sensors for collision detection. This segmentation allows each sensor type to operate in its optimal condition without being affected by liquids, as contact sensors detect mechanical contact directly rather than through dielectric changes.
Solution Approach 2:
The evaluation device acts as an intermediary that processes signals from both capacitive and contact sensors, combining their outputs to provide reliable proximity and collision detection. The contact sensor serves as an intermediary mechanism that detects collision through mechanical contact independent of liquid presence.
2Loss of time
If proximity sensor systems are used, then early warning of approach can be provided, but safety class requirements for immediate error recognition are not met
Solution Approach 1:
The capacitive proximity sensor provides preliminary warning by detecting objects before contact occurs, allowing the system to prepare for potential collisions. The contact sensor then provides the definitive safety-critical detection when actual contact happens, ensuring immediate error recognition meets safety class requirements.
Solution Approach 2:
The system merges the early detection capability of capacitive sensors with the safety-critical detection capability of contact sensors into a unified safety system. This combination allows the system to benefit from both early warning and immediate error recognition, satisfying both response time and safety class requirements.
3Reliability
If separate systems are used for proximity detection and collision recognition, then each function can be optimized, but device complexity increases
Solution Approach 1:
The evaluation device is designed with multi-functionality, processing signals from both capacitive proximity sensors and contact collision sensors through a unified evaluation architecture. This universal evaluation approach reduces overall system complexity while maintaining the reliability benefits of separate optimized sensor systems.
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 sensor apparatus effectively detects both proximity and collision events, providing a safer interaction with medical devices by reducing the risk of injuries and maintaining reliability under varying environmental conditions, including those with liquid contamination.
Implementation Method 1
repeated acquisition of a capacitance value of the sensor element
Implementation Method 2
the dielectricity constant of the medium (e.g., of the measurement range) is so high that an intrusion of a part of a body into the measurement range will no longer be perceived at all
Implementation Method 3
capacitive sensor element with a compressible insulator layer
Implementation Method 4
compressible insulator layer made of a plastic or a foam for example
Data Source
AI summary
Systems and methods are provided for detecting proximity to and collisions with medical devices. A capacitive sensor element includes a compressible insulator layer that has a first conductor track arrangement on a first surface and a second conductor track arrangement on a second surface. The second surface lies opposite the first surface. The sensor apparatus further includes an evaluation device for repeated acquisition of a capacitance value of the sensor element. The evaluation device is configured to output a proximity signal when the respective capacitance value reaches or exceeds a predetermined first threshold value, and is configured to output a collision signal when the respective capacitance value reaches or exceeds a predetermined second threshold value. The second predetermined threshold value is higher than the first predetermined threshold value.