Capacitive Seat Sensor Dielectric Constant Optimization
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Solution Overview
Problem
Existing seat configurations with capacitive coupling sensors for detecting body potential face challenges in maintaining detection accuracy due to limited installation space and changes in electrostatic capacitance caused by occupant posture and vehicle vibration, which degrades the comfort and quality of seating.
Innovation Solution
Incorporating a dielectric material with a higher dielectric constant into the seat's cover member, such as titanium oxide or barium titanate, to increase electrostatic capacitance between the sensor and the occupant's skin, while maintaining comfort and flexibility through the use of application agents, films, or wadding materials with air bubbles, and attachment members made of silicon rubber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the area of the potential detection surface is increased to improve detection accuracy, then the electrostatic capacitance increases, but the installation space in the seat is insufficient
Solution Approach 1:
The patent changes the dielectric constant parameter of the material between the sensor and occupant skin by introducing a dielectric layer with higher dielectric constant than air. This allows increasing electrostatic capacitance without increasing sensor area, resolving the contradiction between detection accuracy and installation space constraints.
Solution Approach 2:
The patent introduces a dielectric layer as an intermediary substance between the sensor electrode and the occupant's skin. This dielectric layer has higher dielectric constant than air, thereby increasing the electrostatic capacitance and improving detection accuracy without requiring larger sensor area.
2Reliability
If the space between the sensor and skin changes due to posture or vibration, then the electrostatic capacitance changes, but the detection accuracy degrades
Solution Approach 1:
The patent changes the dielectric constant parameter from air (low) to dielectric material (high), which increases the electrostatic capacitance value and makes it less sensitive to distance changes. This improves reliability by reducing the impact of posture and vibration-induced space variations.
3Measurement precision
If a dielectric is added to increase electrostatic capacitance, then detection accuracy improves, but the comfort and sense of seating may be degraded
Solution Approach 1:
The patent employs porous dielectric material or dielectric material with air bubbles that maintains flexibility and conformability to the occupant's body. This porous structure allows the dielectric layer to adapt to body contours without creating discomfort, while still providing the high dielectric constant needed for improved detection accuracy.
Solution Approach 2:
The patent carefully selects dielectric materials with appropriate physical properties (flexibility, softness, conformability) in addition to high dielectric constant. This ensures that the dielectric layer improves detection accuracy while maintaining seating comfort by adapting to body contours.
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 the detection accuracy of body potential without compromising the comfort and quality of seating, effectively addressing the issues of reduced capacitance due to posture changes and vehicle vibrations.
Implementation Method 1
a portion of the seat facing the sensor includes a dielectric configured to increase a dielectric constant of the portion
Implementation Method 2
The sensor is a capacitive coupling sensor configured to detect the body potential through the cover member
Data Source
AI summary
A seat configured so that the accuracy of detection of each sensor provided in the seat to detect the body potential of a seated occupant can be improved without degrading the sense and comfort of the seat. A seat includes a trim cover having a contact surface for a seated occupant, and sensors arranged opposite to the contact surface and configured to detect the body potential of the seated occupant. Each sensor is a capacitive coupling sensor configured to detect the body potential through the trim cover. Moreover, a portion of the seat facing each sensor includes a dielectric configured to increase the dielectric constant of such a portion.