Vehicle Seat Sensor Mat with Incompressible Spacer
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Solution Overview
Problem
Existing occupant sensing systems in vehicle seats face variability in capacitive coupling between the sensor electrode and the heater element, leading to inaccurate determination of occupant presence due to variable capacitive coupling, which is exacerbated by the need for additional components like shield electrodes to mitigate this issue, increasing system complexity and cost.
Innovation Solution
The integration of an incompressible spacer between the sensor electrode and the heater element, formed from flexible, thermally conductive materials like silver ink and PTC layers, maintains consistent capacitive coupling and reduces thermal and capacitive variability, eliminating the need for a shield electrode, thereby simplifying the system and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shield electrode is added between the sensor electrode and heater element to reduce capacitive coupling variability, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the shield electrode from the system entirely. Instead of adding a guard element between the sensor electrode and heater element, the invention uses the heater element itself as the sole sensing element, eliminating the need for separate shield components and reducing system complexity while maintaining detection accuracy through alternative signal processing methods
Solution Approach 2:
The heater element serves dual functions: it provides thermal heating to the occupant and simultaneously acts as the sensing element for occupant detection. By making the heater element multi-functional, the patent eliminates the need for separate sensor and shield electrodes, thereby reducing device complexity while maintaining measurement precision through sophisticated signal analysis
2Measurement precision
If a shield electrode is added between the sensor electrode and heater element to reduce capacitive coupling variability, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the shield electrode from the system entirely. Instead of adding a guard element between the sensor electrode and heater element, the invention uses the heater element itself as the sole sensing element, eliminating the need for separate shield components and reducing system complexity while maintaining detection accuracy through alternative signal processing methods
Solution Approach 2:
The heater element serves dual functions: it provides thermal heating to the occupant and simultaneously acts as the sensing element for occupant detection. By making the heater element multi-functional, the patent eliminates the need for separate sensor and shield electrodes, thereby reducing device complexity while maintaining measurement precision through sophisticated signal analysis
3Device complexity
If variable capacitive coupling between sensor electrode and heater element is allowed, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The heater element serves its own dual purpose as both the heating element and the sensing element. By using the heater element itself to detect occupant presence and characteristics, the system eliminates the need for separate sensor electrodes and shield elements. The signal processing circuitry analyzes the electrical characteristics of the heater element to determine occupant information, achieving accurate detection without increasing physical system complexity
Solution Approach 2:
The heater element serves dual functions: it provides thermal heating to the occupant and simultaneously acts as the sensing element for occupant detection. By making the heater element multi-functional, the patent eliminates the need for separate sensor and shield electrodes, thereby reducing device complexity while maintaining measurement precision through sophisticated signal analysis
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 accuracy and reliability of occupant detection by minimizing capacitive coupling variability, allowing for precise determination of occupant presence and size, reducing system complexity and cost, while maintaining comfort and thermal efficiency.
Implementation Method 1
variable capacitive coupling between the sensor electrode and the heater element causes undesirable variability when determining occupant presence
Implementation Method 2
formed from flexible, thermally conductive materials like silver ink and PTC layers
Data Source
Figure 1
Figure 2
AI summary
An occupant sensor mat (40) configured to be located proximate to a seating surface (34) of a vehicle seat assembly (12). The mat (40) includes a sensor electrode (24) formed of conductive material and configured to radiate an electric field (25) in response to an excitation signal (26) for determining an occupant (16) presence proximate to the seating surface (34). A heater element (28) is configured to underlie the sensor electrode (24). The heater element (28) is formed of conductive material and configured to radiate heat in response to electrical current for warming an occupant (16) residing on the seating surface (34). An incompressible spacer (46) is interposed between the sensor electrode (24) and the heater element (28). The incompressible spacer (46) formed of a material sufficiently flexible for locating proximate to a seating surface (34), and sufficiently incompressible to prevent a substantial change in capacitive coupling between the sensor electrode (24) and the heater element (28) from before to while an occupant (16) resides on the seating surface (34).